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Sample records for quaternary sediments mineralogy

  1. Clay Mineralogy of Soils on Quaternary Sediment in Northeast of Urmia

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    Parisa Farzamnia

    2017-03-01

    Full Text Available Introduction: Minerals are one of the main components of soils which play different roles in the soils. Minerals make up about 50% of the volume of most soils. They provide physical support for plants, and create the water- and air-filled pores that make plant growth possible. Mineral weathering releases plant nutrients which are retained by other minerals through adsorption, cation exchange, and precipitation. Minerals are indicators of the amount of weathering that has taken place, and the presence or absence of particular minerals gives clues to how soils have been formed. The physical and chemical characteristics of soil minerals are important consideration in planning, constructing, and maintaining of buildings, roads, and airports. Clay minerals can be used for understanding of soil formation, optimum management of dry and wet lands and interpretation of paleo environments. Moreover, clay minerals can provide some valuable information such as the origin of sediments, transportation and precipitation of sediments and also some information about intercontinental weathering regimes. Quaternary sediments have occupied most of the agricultural and natural resources of Urima plain and recognition of mineralogical of these soils is essential to optimum and stabile use of these soils. Additionally, caly mineralogical investigation can provide some information about the intensity of weathering processes and climate change in this area. Thus, in this study clay minerals of quaternary sediments in northeast of Urmia and the mechanisms of their formation and also tracing probable climate change in this area were investigated. Materials and Methods: This study was performed in theUrmia plain in west Azerbaijan Province. The study area is located on quaternary sediments and physiographically, this area is a part of a river alluvial plain with the gentle slope toward Urmia Lake. The mean annual precipitation and temperature of this area are 345.37 mm and

  2. Grain surface features and clay mineralogy of the quaternary sediments from Western Deccan Trap Region, India, and their palaeoclimatic significance

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    Veena U. Joshi

    2011-06-01

    Full Text Available Quartz sand grains obtained from a deeply gullied topography along the banks of two tributaries of River Pravara in Maharashtra (India have been examined with a scanning electron microscope (SEM. Quartz grains have been selected after a heavy mineral separation and micro-photographs of each grain were taken at various angles and magnifications. The sediments reveal features resulting from mechanical grinding as well as from chemical alteration. Conchoidal fractures, cleavage planes, grooves, v-shaped indentations etc. are the mechanical features documented on the grains whereas solution pits of varying sizes and intensity, precipitation surfaces, oriented v-pits, solution crevasses and etching are the features of chemical origin. Several evidences indicate that the samples have undergone digenetic changes. Few grains show the features of intense chemical breakdown. The overall assemblages of the grain surface features suggest that the samples have been subjected to subaqueous transport for a considerable period of time. The minor chemical features such as solution pits or semi circular arcuate steps found in abundance on these grains are due to the dissolution of the sediments in a low energy fluviatile environment. For clay mineralogy, fractions between <2 and <0.2 mm were separated out from the sediments. The clay fractions were then subjected to examination by X-ray diffraction (XRD of oriented K/Ca saturated samples using a Philips Diffractometer and Ni-filtered Cu Ka radiation with the scanning speed of 10 2Ө min -1. The main clay minerals for all the samples are identical and show the presence of hydroxy-interlayered smectites with minor quantities of mica, kaolinite, smectites, quartz and feldspar. The first weathering product of the Deccan Basalt (DB is the dioctahedral smectite. Since the present semi aridic climatic condition of the study area can not transform a smectite to HIS and either smectite to kaolin, it is quite likely that

  3. Magnetism of quaternary sediments

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    Heller, Friedrich

    Magnetism of Quaternary sediments was the topic of a well-attended symposium held during the 13th INQUA (International Union of Quaternary Research) congress in Beijing, China, August 2-9. More than 40 papers were delivered by scientists from Belgium, England, France, Germany, Japan, New Zealand, Sweden, Switzerland, Taiwan, the United States, the Soviet Union, Yugoslavia, and other countries. The host country contributed to a productive session that was part of the first large scientific meeting to take place in Beijing after the June 4, 1989, upheaval.Nearly half of the studies focused on paleomagnetic and rock magnetic properties of loess in Alaska, Central Asia, China, and New Zealand. Magnetostratigraphic polarity dating was done at some sections in the western (Shaw et al.) and central Chinese loess plateau (Bai and Hus; Wang and Evans; Yue). The interpretation of the polarity pattern found in the western loess plateau still is not unambiguous. In the central part, certain polarity boundaries, such as the Brunhes/Matuyama (B/M) boundary, are found in slightly different stratigraphic positions (Hus et al.; Yue). In deep-sea sediments the lock-in depth of natural remanent magnetization (NRM) at the B/M boundary seems to be a linear function of sedimentation rate (de Menocal et al.). Although the magnetization process in the Chinese loess is not well understood, detailed records of polarity transitions have been reported for the B/M and the Jaramillo R→N transition (Ma et al.; Rolph).

  4. Mineralogical and geological study of quaternary deposits and weathering profiles

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Gi Young; Lee, Bong Ho [Andong National Univ., Andong (Korea, Republic of)

    2004-01-15

    Movement history of a quaternary reverse fault cutting marine terrace deposit and tertiary bentonite in the Yangnammyon, Gyoungju city was studied by the mineralogical and microtextural analysis of the fault clays and weathered terrace deposits. Two types of fault clays were identified as greenish gray before the deposition of the marine terrace deposits and reddish brown after deposition. Greenish gray fault clay is composed mostly of smectite probably powdered from bentonite showing at least two events of movement from microtextures. After the bentonite was covered by quaternary marine gravel deposits, the reverse fault was reactivated cutting marine gravel deposits to form open spaces along the fault plane which allowed the hydrological infiltration of soil particles and deposition of clays in deep subsurface. The reddish brown 'fault' clays enclosed the fragments of dark brown ultrafine varved clay, proving two events of faulting, and slicken sides bisecting reddish brown clays suggest another faulting event in the final stage. Mineralogical and microtextural analysis of the fault clay show total five events of faulting, which had not been recognized even by thorough conventional paleoseismological investigation using trench, highlighting the importance of microtextural and mineralogical analysis in paleoseismology.

  5. Mineralogical Signatures in Electrically Coupled Marine Sediments

    Science.gov (United States)

    Bauermeister, A.; Gorby, Y. A.; Schramm, J.

    2014-12-01

    'Electric cable bacteria' are organisms of the family Desulfobulbaceaethat exhibit a novel method of electron transport. Cells form conductive filaments that function like electric wires, transferring electrons over distances of more than 1 cm from deep sulfidic sediments to oxygen or other electron acceptors near the soil/water interface. The rate of electron transfer across redox boundaries far exceeds that of diffusion limited processes and generates pH gradients that can significantly influence geochemical reactions, leading to the formation of distinct mineralogical profiles unlikely to be created by abiotic means. Electrically coupled sediments are characterized by carbonate and iron sulfide dissolution reactions occurring at depth and formation of carbonate and metal oxide crusts at the surface, exhibiting a reverse pattern compared to conventional sediment geochemistry. Our research seeks to address the following questions: How prevalent are electric cable bacteria in diverse environments? How do biogeochemical conditions such as ion concentration influence mineral formation? Do biogenic minerals participate in charge transfer? What is the importance of electric charge transfer in the subsurface or other low energy habitats? Can mineral banding patterns caused by cable bacteria activity be preserved in the geologic record? With this research we hope to further elucidate the impact of biologically-induced electric fields on the mineralogy of sediments.

  6. Paleomagnetic research on Black Sea Quaternary sediments

    Science.gov (United States)

    Kalcheva, V.; Nozharov, P.; Kovacheva, M.; Shopov, V.

    1990-10-01

    The paper reports the first paleomagnetic study of a Black Sea Quaternary sediment core made by a Bulgarian research group. The experimental results show an important difference in magnetic behaviour between the samples from the Holocene part and those from the Pleistocene part of the core. Suggestions are made for the character of the remanent magnetization and the main carriers of it. The presence of greigite (Fe 3S 4) and pyrite (FeS 2) is discussed. A rough correlation is established between the variation of inclination for the Holocene part of the sediment and for the Bulgarian archeomagnetic curve. On the basis of the comparison of inclination data obtained from the Pleistocene part of the core and previously studied Black Sea core (related to the absolute time scale), it is suggested that the lower boundary of the Pleistocene part is ˜ 16000 years old (BP).

  7. Mineralogy of Rocks and Sediments at Gale Crater, Mars

    Science.gov (United States)

    Achilles, Cherie; Downs, Robert; Blake, David; Vaniman, David; Ming, Doug; Rampe, Elizabeth; Morris, Dick; Morrison, Shaunna; Treiman, Allan; Chipera, Steve; Yen, Albert; Bristow, Thomas; Craig, Patricia; Hazen, Robert; Crisp, Joy; Grotzinger, John; Des Marias, David; Farmer, Jack; Sarrazin, Philippe; Morookian, John Michael

    2017-04-01

    The Mars Science Laboratory rover, Curiosity, is providing in situ mineralogical, geochemical, and sedimentological assessments of rocks and soils in Gale crater. Since landing in 2012, Curiosity has traveled over 15 km, providing analyses of mudstones and sandstones to build a stratigraphic history of the region. The CheMin X-ray diffraction (XRD) instrument is the first instrument on Mars to provide quantitative mineralogical analyses of drilled powders and scooped sediment based on X-ray crystallography. CheMin identifies and determines mineral abundances and unit-cell parameters of major crystalline phases, and identifies minor phases at abundances >1 wt%. In conjunction with elemental analyses, CheMin-derived crystal chemistry allows for the first calculations of crystalline and amorphous material compositions. These mineralogy, crystal chemistry, and amorphous chemistry datasets are playing central roles in the characterization of Gale crater paleoenvironments. CheMin has analyzed 17 rock and sediment samples. In the first phase of the mission, Curiosity explored the sedimentary units of Aeolis Palus (Bradbury group), including two mudstones from Yellowknife Bay. CheMin analyses of the Yellowknife Bay mudstones identified clay minerals among an overall basaltic mineral assemblage. These mineralogical results, along with imaging and geochemical analyses, were used to characterize an ancient lacustrine setting that is thought to have once been a habitable environment. Following the investigations of the Bradbury group, Curiosity arrived at the lower reaches of Aeolis Mons, commonly called Mt. Sharp. A strategic sample campaign was initiated, drilling bedrock at primary sandstone and show decreased abundances of feldspar and pyroxene, and an increase in the amorphous component, specifically high-silica phases. The Murray formation is the most sampled stratigraphic unit in Gale crater. Composed mainly of finely laminated mudstones and interpreted as lacustrine

  8. Late Quaternary sedimentation in eastern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O; Mascarenhas, A; Paropkari, A; Rao, Ch.M.

    This study presents variations in various size measures, calcium carbonate, organic carbon, clay mineralogy and major and trace elements in a core (5.40 m long, 2713 m depth) from the eastern Bay of Bengal. On a CM diagram, the sediments of the core...

  9. Carbonate mineralogy and faunal relationship in tropical shallow water marine sediments: Cape Comorin, India

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Nair, R.R.; Kidwai, R.M.; Rao, V.P.

    The carbonate mineralogy of Recent sediments from the western and eastern continental shelves around Cape Comorin off the southern tip of India was determined by X-ray diffraction analyses. The results show that in the sediments where benthic...

  10. Provenance of the Quaternary Southern Kalahari sediments: A wetland that became dry

    Science.gov (United States)

    Vainer, Shlomy; Erel, Yigal; Matmon, Ari

    2017-04-01

    The ca. 140 Ma vast Kalahari basin is characterized by uplifted margins, terrestrial sedimentation within semi endorheic sub-basins, subdued morphology and tectonic quiescence. This intracratonic basin has been subjected to a prolonged period of subsidence affecting its sedimentary fill by changing plate motion and climatic cycles. Provenance studies of Kalahari Group sediments mainly focused on the easily accessible uppermost part that represents only the last phase of sedimentation, leaving unresolved questions for the rest of the strata. The Southern Kalahari Group succession exposed along the walls of the Mamatwan Mine, Northern Cape, South Africa, reveals three main depositional environments; a bottom pluvial, low-energy water body, a middle fluvial, high-energy environment and an upper aeolian sandy unit. The entire section, which was deposited within the Quaternary, records significant environmental and depositional changes suggesting a highly dynamic landscape. The fully exposed section (55 m) of the Kalahari Group at Mamatwan Mine was analysed for its mineralogy, elemental composition, Sr, Nd and Pb isotopic ratios and iron species. Mineralogical assemblage imply that a saline and alkaline shallow water-body existed during the early-middle Pleistocene contemporaneous with relative dense hominine occupation of the area. Isotopic ratios were used to determine the source of the sediments, which was found to be mainly of mafic rocks located to the north-east of Mamatwan. Weathering sensitive indices of both elemental ratios and iron phases show that sediments carried to the basin underwent considerable weathering indicative to a greater availability of surface water than the present. The lacustrine environment was rapidly filled with clasts that were derived mainly from the surrounding hills and experienced limited degree of chemical weathering during transport, but underwent subsequent groundwater alteration by iron-rich solution and precipitation of celcrete

  11. Detrital cave sediments record Late Quaternary hydrologic and climatic variability in northwestern Florida, USA

    Science.gov (United States)

    Winkler, Tyler S.; van Hengstum, Peter J.; Horgan, Meghan C.; Donnelly, Jeffrey P.; Reibenspies, Joseph H.

    2016-04-01

    Detrital sediment in Florida's (USA) submerged cave systems may preserve records of regional climate and hydrologic variability. However, the basic sedimentology, mineralogy, stratigraphic variability, and emplacement history of the successions in Florida's submerged caves remains poorly understood. Here we present stratigraphic, mineralogical, and elemental data on sediment cores from two phreatic cave systems in northwestern Florida (USA), on the Dougherty Karst Plain: Hole in the Wall Cave (HITW) and Twin Cave. Water flowing through these caves is subsurface flow in the Apalachicola River drainage basin, and the caves are located just downstream from Jackson Blue (1st magnitude spring, > 2.8 m3 s- 1 discharge). Sedimentation in these caves is dominated by three primary sedimentary styles: (i) ferromanganese deposits dominate the basal recovered stratigraphy, which pass upsection into (ii) poorly sorted carbonate sediment, and finally into (iii) fine-grained organic matter (gyttja) deposits. Resolving the emplacement history of the lower stratigraphic units was hampered by a lack of suitable material for radiocarbon dating, but the upper organic-rich deposits have a punctuated depositional history beginning in the earliest Holocene. For example, gyttja primarily accumulated in HITW and Twin Caves from ~ 5500 to 3500 cal yr. BP, which coincides with regional evidence for water-table rise of the Upper Floridian Aquifer associated with relative sea-level rise in the Gulf of Mexico, and evidence for invigorated drainage through the Apalachicola River drainage basin. Gyttja sediments were also deposited in one of the caves during the Bølling/Allerød climate oscillation. Biologically, these results indicate that some Floridian aquatic cave (stygobitic) ecosystems presently receive minimal organic matter supply in comparison to prehistoric intervals. The pre-Holocene poorly sorted carbonate sediment contains abundant invertebrate fossils, and likely documents a period

  12. Determination of sediment provenance by unmixing the mineralogy of source-area sediments: The "SedUnMix" program

    Science.gov (United States)

    Andrews, John T.; Eberl, D.D.

    2012-01-01

    Along the margins of areas such as Greenland and Baffin Bay, sediment composition reflects a complex mixture of sources associated with the transport of sediment in sea ice, icebergs, melt-water and turbidite plumes. Similar situations arise in many contexts associated with sediment transport and with the mixing of sediments from different source areas. The question is: can contributions from discrete sediment (bedrock) sources be distinguished in a mixed sediment by using mineralogy, and, if so, how accurately? To solve this problem, four end-member source sediments were mixed in various proportions to form eleven artificial mixtures. Two of the end-member sediments are felsic, and the other two have more mafic compositions. End member and mixed sediment mineralogies were measured for the Elsevier B.V..

  13. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152310 Hao Penghao(National Defense Key Discipline Lab.of Nuclear Waste and Environmental Safety,Southwest University of Science and Technology,Mianyang 621010,China);Lu Xirui Structural Evolvement and the Capability of Resistance toγ-Ray Irradiation on Zircon Originated from the North Qaidam(Journal of Mineralogy and Petrology,

  14. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20130742 Huang Dubin (School of Geoscience and Surveying Engineering , China University of Mining and Technology , Beijing 100083 , China); Guan Xinbang Study on the Minera-logical Features of Chloritoid in Hongmiaoling Formation of Dongshan , Tanzhesi , West Beijing , China (Acta Mineralogica Sinica , ISSN1000-4734 , CN52-1045/P

  15. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20112225Du Guangpeng(Shanghai Jianqiao College,Shanghai 201319,China);Fan Jianliang Characteristics of Raman Spectral of Calcite Group Minerals(Journal of Mineralogy and Petrology,ISSN1001 - 6872, CN51-1143/TD,30(4),2010,p.32-35, 2illus.,2tables,6refs.)

  16. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>20080144 Ma Guohua(Southwest University of Science and Technology,Mianyang 621002,China);Peng Tongjiang A Study of Chrysotile Asbestos Nanotube Synthesized by Hydrothermal Reaction(Journal of Mineralogy and Petrology,ISSN1001-6872,CN51-1143/TD,27(1),2007,p.40-45,2 illus.,2 photos,11 refs.)

  17. Mineralogical, geochemical, and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)

    Science.gov (United States)

    Gamboa, Adriana; Montero-Serrano, Jean-Carlos; St-Onge, Guillaume; Rochon, André; Desiage, Pierre-Arnaud

    2017-02-01

    Mineralogical, geochemical, magnetic, and siliciclastic grain-size signatures of 34 surface sediment samples from the Mackenzie-Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox-sensitive elements (Mn, Fe, V, Cr, Zn) indicate that modern sedimentary deposition within the Mackenzie-Beaufort Sea Slope and Amundsen Gulf took place under oxic bottom-water conditions, with more turbulent mixing conditions and thus a well-oxygenated water column prevailing within the Amundsen Gulf. The analytical data obtained, combined with multivariate statistical (notably, principal component and fuzzy c-means clustering analyses) and spatial analyses, allowed the division of the study area into four provinces with distinct sedimentary compositions: (1) the Mackenzie Trough-Canadian Beaufort Shelf with high phyllosilicate-Fe oxide-magnetite and Al-K-Ti-Fe-Cr-V-Zn-P contents; (2) Southwestern Banks Island, characterized by high dolomite-K-feldspar and Ca-Mg-LOI contents; (3) the Central Amundsen Gulf, a transitional zone typified by intermediate phyllosilicate-magnetite-K-feldspar-dolomite and Al-K-Ti-Fe-Mn-V-Zn-Sr-Ca-Mg-LOI contents; and (4) mud volcanoes on the Canadian Beaufort Shelf distinguished by poorly sorted coarse-silt with high quartz-plagioclase-authigenic carbonate and Si-Zr contents, as well as high magnetic susceptibility. Our results also confirm that the present-day sedimentary dynamics on the Canadian Beaufort Shelf is mainly controlled by sediment supply from the Mackenzie River. Overall, these insights provide a basis for future studies using mineralogical, geochemical, and magnetic signatures of Canadian Arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late Quaternary climate and oceanographic changes.

  18. Estimated Thickness of Quaternary Sediment in the Wood River Valley aquifer system, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is the estimated thickness of Quaternary sediment of the Wood River Valley aquifer system. This isopach map was constructed by subtracting the estimated...

  19. Influence of mineralogical and heavy metal composition on natural radionuclide concentrations in the river sediments.

    Science.gov (United States)

    Suresh, G; Ramasamy, V; Meenakshisundaram, V; Venkatachalapathy, R; Ponnusamy, V

    2011-10-01

    The natural radiation level has been determined for the sediment samples of the Ponnaiyar River with an aim of evaluating the radiation hazard. The mineralogical characterizations of the sediments have been carried out using the Fourier Transform Infrared (FTIR) spectroscopic technique. The relative distribution of major minerals is determined by calculating extinction coefficient. The concentration and spatial distribution of heavy metals (Pb, Cr, Cu, Zn and Ni) have been studied to understand the heavy metal contamination and its level of toxicity. To evaluate the potential toxicity, heavy metal concentrations are compared with different toxicological and geological reference values. The comparison results suggest that the present metals create an adverse effect on the aquatic ecosystems associated with this river. To assess the sediment contamination due to the studied heavy metals, the Pollution Load Index (PLI) is calculated. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from radioactivity, mineralogical and geochemical analysis to know the existing relations. Obtained results showed that the effect of mineralogy on level of radioactivity should be significant. However, mineralogy effect on heavy metal composition in the sediments should be limited, indicating that other factors such as vicinity of the pollution sources are more important. Also, the influence of mineralogical characterization on level of radioactivity is significant, whereas the influence of the heavy metal composition on level of radioactivity should be limited.

  20. Geochemical and mineralogical evidence for Sahara and Sahel dust additions to Quaternary soils on Lanzarote, eastern Canary Islands, Spain

    Science.gov (United States)

    Muhs, D.R.; Budahn, J.; Skipp, G.; Prospero, J.M.; Patterson, D.; Bettis, E. Arthur

    2010-01-01

    Africa is the most important source of dust in the world today, and dust storms are frequent on the nearby Canary Islands. Previous workers have inferred that the Sahara is the most important source of dust to Canary Islands soils, with little contribution from the Sahel region. Soils overlying a late Quaternary basalt flow on Lanzarote, Canary Islands, contain, in addition to volcanic minerals, quartz and mica, exotic to the island's bedrock. Kaolinite in the soils also likely has an exotic origin. Trace-element geochemistry shows that the soils are derived from varying proportions of locally derived basalt and African dust. Major-element geochemistry, clay mineralogy and interpretation of satellite imagery suggest that dust additions to the Canary Islands come not only from the Sahara Desert, but also from the Sahel region. ?? Published 2010. This article is a US Government work and is in the public domain in the USA.

  1. The mineralogy and chemistry of fine-grained sediments, Morphou Bay, Cyprus

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    C. Neal

    2002-01-01

    Full Text Available The mineralogy and chemistry of the less than 20μm fraction of marine sediments at Morphou Bay, north-west Cyprus, are presented to characterise fine-grained sediment supplies from basic and ultrabasic rocks of the Troodos Massif within a typological setting. The sediments comprise a mixture of smectite, illite, kaolinite and iron rich chlorite. They also contain amorphous iron oxides/hydroxides, calcite (with some magnesium substitution for calcium and an amphibole. Spatial patterns in mineralogy occur: the near-shore sediments are rich in smectite, chlorite, amphibole and amorphous iron oxides/hydroxides, while the offshore sediments are rich in illite and calcite. The sediments are calcium, magnesium, iron, aluminium and potassium bearing, due to the presence of significant amounts of calcite (for Ca, clay minerals and aluminium and iron oxides/hydroxides. Potassium is present within the micaceous mineral illite, but it is also contained within other phases that are difficult to pinpoint. Statistical analysis reveals that the chemical composition of the sediments broadly follows the mineralogy with the dominant feature being related to spatial changes in the mineralogy. The patterns of change reflect a three component mix of clay-sized sediment types: (1 localised lithogenous sources rich in smectite with subsidiary amounts of amorphous iron oxides/hydroxides and amphibole, from Cyprus, the Troodos in particular, (2 illite rich and smectite chlorite and chlorite bearing material of lithogenous origin from other parts of the eastern Mediterranean and (3 calcite, mainly of marine origin. Keywords: smectite, illite, chlorite, kaolinite, calcite, sediments, Morphou Bay, Troodos, Cyprus, Mediterranean, calcium, potassium, magnesium, iron, silicon, phosphorus.

  2. Clay mineralogical and geochemical proxies of the East Asian summer monsoon evolution in the South China Sea during Late Quaternary

    Science.gov (United States)

    Chen, Quan; Liu, Zhifei; Kissel, Catherine

    2017-01-01

    The East Asian summer monsoon controls the climatic regime of an extended region through temperature and precipitation changes. As the East Asian summer monsoon is primarily driven by the northern hemisphere summer insolation, such meteorological variables are expected to significantly change on the orbital timescale, influencing the composition of terrestrial sediments in terms of both mineralogy and geochemistry. Here we present clay mineralogy and major element composition of Core MD12-3432 retrieved from the northern South China Sea, and we investigate their relationship with the East Asian summer monsoon evolution over the last 400 ka. The variability of smectite/(illite + chlorite) ratio presents a predominant precession periodicity, synchronous with the northern hemisphere summer insolation changes and therefore with that of the East Asian summer monsoon. Variations in K2O/Al2O3 are characterized by eccentricity cycles, increasing during interglacials when the East Asian summer monsoon is enhanced. Based on the knowledge of sediment provenances, we suggest that these two proxies in the South China Sea are linked to the East Asian summer monsoon evolution with different mechanisms, which are (1) contemporaneous chemical weathering intensity in Luzon for smectite/(illite + chlorite) ratio and (2) river denudation intensity for K2O/Al2O3 ratio of bulk sediment. PMID:28176842

  3. Clay mineralogical and geochemical proxies of the East Asian summer monsoon evolution in the South China Sea during Late Quaternary.

    Science.gov (United States)

    Chen, Quan; Liu, Zhifei; Kissel, Catherine

    2017-02-08

    The East Asian summer monsoon controls the climatic regime of an extended region through temperature and precipitation changes. As the East Asian summer monsoon is primarily driven by the northern hemisphere summer insolation, such meteorological variables are expected to significantly change on the orbital timescale, influencing the composition of terrestrial sediments in terms of both mineralogy and geochemistry. Here we present clay mineralogy and major element composition of Core MD12-3432 retrieved from the northern South China Sea, and we investigate their relationship with the East Asian summer monsoon evolution over the last 400 ka. The variability of smectite/(illite + chlorite) ratio presents a predominant precession periodicity, synchronous with the northern hemisphere summer insolation changes and therefore with that of the East Asian summer monsoon. Variations in K2O/Al2O3 are characterized by eccentricity cycles, increasing during interglacials when the East Asian summer monsoon is enhanced. Based on the knowledge of sediment provenances, we suggest that these two proxies in the South China Sea are linked to the East Asian summer monsoon evolution with different mechanisms, which are (1) contemporaneous chemical weathering intensity in Luzon for smectite/(illite + chlorite) ratio and (2) river denudation intensity for K2O/Al2O3 ratio of bulk sediment.

  4. Tertiary and Quaternary sedimentation in a part of the Duero Basin Palencia, (Spain)

    NARCIS (Netherlands)

    Mabesoone, J.M.

    1959-01-01

    Sediments in the foreland of a mountain chain are sometimes suited to reconstitute the conditions in these mountains at the time of deposition of the sediments. The present study gives the results of a sedimentological investigation of the Tertiary and Quaternary deposits in a part of the Duero basi

  5. Sediment mineralogy in the Bay of Havana (Cuba): its relation to natural and anthropogenic processes

    Science.gov (United States)

    Fernández-Turiel, J. L.; Chinchón, J. S.; Maldonado, A.

    1996-02-01

    The mineralogical analysis by means of X-ray diffraction of the surficial sediments from the Bay of Havana (Cuba) allows us to identify and quantify the presence of quartz, feldspars, calcite, magnesium calcite, aragonite and dolomite. The distribution of these minerals permits us to distinguish the occurrence of five sedimentary environments (coastal marine, transitional bay-marine, bay, prodelta and Luyanó Drain environments) and related them to the general trends of sedimentary dynamics in the bay. The mineralogy of the coastal marine sediments is dominated by the composition of the local calcareous substratum, i.e., by magnesium calcite and dolomite. These minerals are associated with aragonite in the transitional environment existing between the marine and the bay environments. The sediments in the bay show high contents of aragonite and calcite, while quartz and feldspars are in important quantities in the sediments from the prodelta environments. These mineralogical features are consistent with the natural processes occuring in the Bay of Havana, while the composition of the sediments from the Luyanó Drain environment seem affected by the anthropogenic supply of this drain, showing very high contents of calcitic biogenic products.

  6. Mineralogy of the carbonate sediments - western continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, R.R.; Hashimi, N.H.

    An X-ray diffraction study of forty-six sediment samples and three oolitic limestone samples from the western continental shelf of India shows that aragonite is the dominant carbonate mineral (99% maximum), followed by low-magnesium calcite (77...

  7. Towards dating Quaternary sediments using the quartz Violet Stimulated Luminescence (VSL) signal

    DEFF Research Database (Denmark)

    Ankjærgaard, C.; Jain, Mayank; Wallinga, J.

    2013-01-01

    Quartz optically stimulated luminescence (OSL) dating is widely used to determine the time of deposition and burial of Late Quaternary sediments. Application of the method is usually limited to the past 150,000 years due to early saturation of the OSL signal. Here we explore the potential to date...... Quaternary sediments using the violet (402 nm) stimulated luminescence (VSL) signal of quartz.We develop and test a new post-blue VSL single aliquot regenerative dose dating protocol, and demonstrate that the VSL signal originates from a deep trap at about 1.9 eV with a thermal lifetime of 1011 years at 10...

  8. Clay Mineralogy of Soils and Sediments from an Alluvial Aquifer, Rifle, Colorado

    Science.gov (United States)

    Elliott, W. C.; Zaunbrecher, L. K.; Lim, D.; Pickering, R. A.; Williams, K. H.; Long, P. E.; Qafoku, N. P.

    2014-12-01

    Alluvial aquifers along the Colorado River corridor in central to western Colorado contain legacy contamination including U, V, As and Se. These alluvial aquifers host important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface that are both significant on their own, but also influence contaminant behavior. Mineral phases likely active in the sequestration of metal contaminants are chlorite, smectite-vermiculite, illite, and smectite. These minerals are also important biogeofacies markers. The Colorado alluvial sediments include lenses of silt and clay that are commonly more reduced than coarser grained materials. The clay minerals that make up the alluvial aquifer sediments include these mineral phases important for metal sequestration (chlorite, smectite, illite), as well as kaolinite and quartz. More specifically, the clay mineralogy of soils derived from these sediments at Rifle are composed of the same suite of minerals found in the alluvial sediments plus a vermiculite-smectite intergrade. The vermiculite-smectite intergrade is a weathering product of illite. The presence of illite and chlorite in both the sediments and the soils at Rifle reflect a mineralogically immature character of the source rocks. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate, indicative of mixed provence of immature (chlorite, smectite, illite) and mature (kaolinite) minerals relative to their source areas.

  9. Lack of cross-shelf transport of sediments on the western margin of India: Evidence from clay mineralogy

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Nair, R.R.

    transported long distances along the shelf, cross-shelf transport appears to be minimal. Confirmatory evidence of qualitative differences in outer and inner shelf clays is provided by sediment trap clay mineralogy on the outer shelf. Clay bound pollutant...

  10. Mineralogical study of surface sediments in the western Arctic Ocean and their implications for material sources

    Institute of Scientific and Technical Information of China (English)

    DONG Linsen; SHI Xuefa; LIU Yanguang; FANG Xisheng; CHEN Zhihua; WANG Chunjuan; ZOU Jianjun; HUANG Yuanhui

    2014-01-01

    Mineralogical analysis was performed on bulk sediments of 79 surface samples using X-ray diffraction. The analytical results, combined with data on ocean currents and the regional geological background, were used to investigate the mineral sources. Mineral assemblages in sediments and their distribution in the study area indicate that the material sources are complex. (1) Feldspar is abundant in the sediments of the middle Chukchi Sea near the Bering Strait, originating from sediments in the Anadyr River carried by the Anadyr Current. Sediments deposited on the western side of the Chukchi Sea are rich in feldspar. Compared with other areas, sediments in this region are rich in hornblende transported from volcanic and sedimentary rocks in Siberia by the Anadyr Stream and the Siberian Coastal Current. Sediments in the eastern Chukchi Sea are rich in quartz sourced from sediments of the Yukon and Kuskokwim rivers carried by the Alaska Coastal Current. Sediments in the northern Chukchi Sea are rich in quartz and carbonates from the Mackenzie River sediments. (2) Sediments of the southern and central Canada Basin contain little calcite and dolomite, mainly due to the small impact of the Beaufort Gyre carrying carbonates from the Canadian Arctic Islands. Compared with other areas, the mica content in the region is high, implying that the Laptev Sea is the main sediment source for the southern and central Canada Basin. In the other deep sea areas, calcite and dolomite levels are high caused by the input of large amounts of sediment carried by the Beaufort Gyre from the Canadian Arctic Islands (Banks and Victoria). The Siberian Laptev Sea also provides small amounts of sediment for this region. Furthermore, the Atlantic mid-water contributes some fine-grained material to the entire deep western Arctic Ocean.

  11. Elemental composition and mineralogical characteristics of coastal marine sediments of Tutuila, American Samoa.

    Science.gov (United States)

    Morrison, R J; Peshut, P J; Lasorsa, Brenda K

    2010-06-01

    Surface sediment samples were collected from 5 pristine coastal areas and 1 potentially contaminated coastal site on Tutuila, the main island of American Samoa, an isolated island group in the South Pacific Ocean. Samples were analysed for total element analysis (15 elements) and mineralogy. The results indicated no evidence of trace element contamination at any site, including Pago Pago Harbour. Inter-site variations could be explained assuming the sediments consisted predominantly of coralline sand and rubble with varying quantities of basaltic materials derived from local catchments.

  12. Mineralogical study on quaternary soils of the Olkiluoto investigation trench OL-TK19

    Energy Technology Data Exchange (ETDEWEB)

    Lukkari, S.; Marmo, J. [Geological Survey of Finland, Espoo (Finland)

    2014-07-15

    Six till samples representing three vertical profiles in a research trench OL TK19 from Olkiluoto were studied for their mineralogy. The client, Posiva Oy, was interested especially in carbonates and sulphides. The study is based on size and density classified subsamples. Mineral distributions were determined by a Scanning Electron Microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), using the INCA FEATURE phase detection and classification software. Lithologies within the cobble fraction are also measured. The study revealed unhomogeneity in the sample material. Sample TK 19/2 POH is rich in calcareous sedimentary rocks and older till compared to the other samples. Three main carbonate-bearing sedimentary rock types are: limestone, carbonate cemented quartz feldspar rock, and quartz graywacke, containing clasts of the carbonate cemented quartz feldspar rock. The contents of heavy minerals (0.1-1.2%) and semi heavy minerals (1.3-3.3%) are low in every sample. Carbonate concentrates of the semi heavy mineral separates are low (0.04-0.57 %). Sulfide is predominately pyrite (1.3-8.6%). Pyrite grains have commonly goethite crusts, which are ubiquitous in the surface samples. Both sulphide and carbonate occurs as liberated grains and as fine grained matrix, enveloping other mineral grains. Phosphorites and phosphorous rock fragments are also common in the till samples. The mode of occurrence of phosphate resembles that of carbonate and sulphides that makes the quantification of these buffer minerals impossible. Sedimentary rocks are interpreted to have been derived from the sedimentary rock pile preserved under the Gulf of Bothnia. (orig.)

  13. Shift in detrital sedimentation in the eastern Bay of Bengal during the late Quaternary

    Digital Repository Service at National Institute of Oceanography (India)

    PrakashBabu, C.; Pattan, J.N.; Dutta, K.; Basavaiah, N.; Prasad, G.V.K.; Ray, D.K.; Govil, P.

    the late Quaternary period. Units 2 (43-24 cm) and 1 (24-0 cm) represent enhanced and reduced supply of coarse-grained detrital sediments from the Ganges River during early and late Holocene period, respectively. Increased terrigenous supply dilutes calcium...

  14. Relationship between water chemistry and sediment mineralogy in the Cerro Prieto geothermal field: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N. (Univ. de Perpignan, France); Thompson, J.M.; Ball, J.W.

    1981-01-01

    The chemical compositions of waters collected from the Cerro Prieto geothermal production wells and hydrothermal emanations are different. Compared to the Cerro Prieto well waters, the surficial waters generally contain significantly less potassium, slightly less calcium and chloride, and significantly more magnesium and sulfate. In comparison to the unaltered sediments, the changes in the mineralogy of the altered sediments appear to be controlled by the type of emanation (well, spring, mud pot, geyser, fumarole, or cold pool). However, an increase in quartz and potassium feldspar percentages seems to be characteristic of the majority of the sediments in contact with geothermal fluids. Preliminary attempts to model the chemical processes occurring in the Cerro Prieto geothermal field using chemical equilibrium calculations are reported. For this purpose the chemical compositions of thermal waters (well and surficial emanation) were used as input data to make calculations with SOLMNEQ and WATEQ2 computer programs. Then the theoretical mineral composition of altered sediments was predicted and compared to the mineralogy actually observed in the solid samples.

  15. Luminescence dating of Late Quaternary sediments from East Greenland

    DEFF Research Database (Denmark)

    Mejdahl, V.; Funder, Svend Visby

    1994-01-01

    Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow-marine/coastal-fluvial and ......Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow...

  16. Luminescence dating of Late Quaternary sediments from East Greenland

    DEFF Research Database (Denmark)

    Mejdahl, V.; Funder, Svend Visby

    1994-01-01

    Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow-marine/coastal-fluvial and ......Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow...

  17. Combined mineralogical and EXAFS characterization of polluted sediments for the definition of technological variables and constraints

    Science.gov (United States)

    Brigatti, M. F.; Elmi, C.; Laurora, A.; Malferrari, D.; Medici, L.

    2009-04-01

    An extremely severe aspect, both from environmental and economic viewpoint, is the management of polluted sediments removed from drainage and irrigation canals. Canals, in order to retain their functionality over the time, need to have their beds, periodically cleaned from sediments there accumulating. The management of removed sediments is extremely demanding, also from an economical perspective, if these latter needs to be treated as dangerous waste materials, as stated in numerous international standards. Furthermore the disposal of such a large amount of material may introduce a significant environmental impact as well. An appealing alternative is the recovery or reuse of these materials, for example in brick and tile industry, after obviously the application of appropriate techniques and protocols that could render these latter no longer a threat for human health. The assessment of the effective potential danger for human health and ecosystem of sediments before and after treatment obviously requires both a careful chemical and mineralogical characterization and, even if not always considered in the international standards, the definition of the coordination shell of heavy metals dangerous for human health, as a function of their oxidation state and coordination (e.g. Cr and Pb), and introducing technological constraints or affecting the features of the end products. Fe is a good representative for this second category, as the features of the end product, such as color, strongly depend not only from Fe concentration but also from its oxidation state, speciation and coordination. This work will first of all provide mineralogical characterization of sediments from various sampling points of irrigation and drainage canals of Po river region in the north-eastern of Italy. Samples were investigated with various approaches including X-ray powder diffraction under non-ambient conditions, thermal analysis and EXAFS spectroscopy. Obtained results, and in particular

  18. Palaeoclimatic Indicators of China's Quaternary Saline Lake Sediments and Hydrochemistry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and give climatic parameters under the conditions of typical cold phase (mirabilite and natron), warm phase (thenardite) and slightly warm phase (bloedite) saline lake deposition.

  19. Cretaceous to Quaternary Siliciclastic Sediments of the Tarfaya Basin, Marginal Atlantic, SW Morocco Petrography, Geochemistry, Provenance, Climate and Weathering

    OpenAIRE

    Ali, Sajid

    2012-01-01

    This dissertation is prepared to attain the doctorate under the title "Cretaceous to Quaternary Siliciclastic Sediments of the Tarfaya Basin, Marginal Atlantic, SW Morocco Petrography, Geochemistry, Provenance, Climate and Weathering".

  20. Eolian sediment responses to late Quaternary climate changes: Temporal and spatial patterns in the Sahara

    Science.gov (United States)

    Swezey, C.

    2001-01-01

    This paper presents a compilation of eolian-based records of late Quaternary climate changes in the Sahara. Although the data are relatively sparse, when viewed as a whole, they reveal a general pattern of widespread eolian sediment mobilization prior to 11,000 cal. years BP, eolian sediment stabilization from 11,000 to 5000 cal. years BP, and a return to widespread eolian sediment mobilization after 5000 cal. years BP. Furthermore, an eolian-based record from southern Tunisia reveals the existence of millennial-scale changes in eolian sediment behavior. These millennial-scale variations provide examples of eolian sediment responses to climate changes at a scale intermediate between seasonal and orbital ('Milankovitch') changes, and they are also coincident with abrupt atmospheric and oceanic changes. The general synchroneity of the eolian stratigraphic records and their coincidence with various oceanic and atmospheric changes suggest that global forcing mechanisms have influenced late Quaternary eolian sediment behavior in the Sahara. ?? 2001 Elsevier Science B.V.

  1. Sources and contamination rate of port sediments: evidences from dimensional, mineralogical, and chemical investigations

    Science.gov (United States)

    Lucchetti, Gabriella; Cutroneo, Laura; Carbone, Cristina; Consani, Sirio; Vagge, Greta; Canepa, Giuseppe; Capello, Marco

    2017-04-01

    Ports are complex environments due to their complicated geometry (quays, channels, and piers), the presence of human activities (vessel traffic, yards, industries, and discharges), and natural factors (stream and torrent inputs, sea action, and currents). Due to the many activities that take place in a port, sediments and waters are often contaminated by different kinds of chemicals, such as hydrocarbons, dioxins, pesticides, nutrients, and metals. The contamination rate of a port basin is site specific and depends on the sources of contamination in the nearby urban system as well as the port system itself, such as city discharges and sewers, river intake, vessel traffic, factories (Taylor and Owens, 2009). Moreover, two important sources and vehicles of contaminants are: a) anthropogenic road deposited sediments derived from the runoff of the port and city area, and natural road deposited sediments derived from rivers and torrents, and b) airborne particulate matter and sediments (Taylor and Owens, 2009). The Port of Genoa is situated at the apex of the Ligurian Sea in the north western Mediterranean Sea and is characterised by the presence of several commercial activities that have contributed, over the years, and still contribute today, to the contaminant accumulation in both the water column and the bottom sediments. This port basin includes the mouth of several streams and the mouth of the Bisagno and the Polcevera Torrents, along the banks of which can be found several small towns, quarries, factories, and the suburbs of the city of Genoa, a ferry terminal, different container terminals, marinas, dry docks, the coal power plant of Genoa, and different wastewater treatment plant discharges. Starting from these considerations, we have examined the marine environment of a port from the point of view of the water mass circulation, hydrological characteristics, distribution of the sediment grain size, mineralogical characteristics, and metal concentrations of the

  2. Mineralogical, optical, geochemical, and particle size properties of four sediment samples for optical physics research

    Science.gov (United States)

    Bice, K.; Clement, S. C.

    1981-01-01

    X-ray diffraction and spectroscopy were used to investigate the mineralogical and chemical properties of the Calvert, Ball Old Mine, Ball Martin, and Jordan Sediments. The particle size distribution and index of refraction of each sample were determined. The samples are composed primarily of quartz, kaolinite, and illite. The clay minerals are most abundant in the finer particle size fractions. The chemical properties of the four samples are similar. The Calvert sample is most notably different in that it contains a relatively high amount of iron. The dominant particle size fraction in each sample is silt, with lesser amounts of clay and sand. The indices of refraction of the sediments are the same with the exception of the Calvert sample which has a slightly higher value.

  3. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R.; Smith, R.P.

    1992-09-01

    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  4. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R.; Smith, R.P.

    1992-01-01

    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  5. Shifting sources and transport paths for the late Quaternary Escanaba Trough sediment fill (northeast Pacific)

    Science.gov (United States)

    Zuffa, G.G.; De Rosa, R.; Normark, W.R.

    1997-01-01

    Escanaba Trough, which forms the southernmost part of the axial valley of the actively spreading Gorda Ridge, is filled with several hundred meters of sediment of presumed late Quaternary age. Surficial sediment samples from gravity cores, deeper samples (as much as 390 m) from Site 35 of the Deep Sea Drilling Program (Leg 5), and the acoustic character of the sediment fill observed on seismic-reflection profiles indicate that much of the sediment fill is of turbidite origin. Gross composition and heavy- mineral analyses of sand samples show that two distinct petrofacies comprise the sediment fill. The lower part of the fill was derived primarily from the Klamath River source of northern California while the younger fill, including the surficial sand beds, are from the Columbia River drainage much farther north. The Escanaba Trough sediment provides an opportunity to evaluate concepts for paleogeographic and paleotectonic reconstructions that are based on facies analysis and compositional and textural data for the volcanic components because both intrabasinal and extrabasinal sources are present as well as coeval (neovolcanic) and non coeval (paleovolcanic) sourcre This study of a modern basin shows, that although the sediment sources could be identified, it was useful to have some knowledge of the sediment pathway(s), the effects of diagenesis, and the possible effects of sediment sorting as a result of long transport distances from the source area for some components. Application of these same techniques to ancient deposits without benefit of the additional parameters will face limitations.

  6. Enrichment of arsenic in the Quaternary sediments from Ankaleshwar industrial area, Gujarat, India: an anthropogenic influence.

    Science.gov (United States)

    Shirke, K D; Pawar, N J

    2015-09-01

    Arsenic (As) contamination of sediments and waters is known from Bengal and other parts of eastern and central India. However, there is paucity of reports that document occurrence of As in Quaternary sediments from western India. In this paper, we report the enrichment of As in the Quaternary sediments of Ankaleshwar area in the western Indian state of Gujarat. Twenty-five surface and five profile samples were analyzed that indicated spatial and vertical distribution of As in the sediments. The As content of fine size fractions (63 μm) compared with upper continental crust (UCC) and standard shale indicates anomalous As enrichment that is supported by moderate to high geo-accumulation index (Igeo) as well as pollution index (Pi). Enrichment of As is seen in surface sediments from the industrial and urban land use regions, followed by oil field and agricultural land suggesting strong influence of anthropogenic factors. Although the arsenic concentration decreases with depth, the relatively higher values of As coupled with Igeo and Pi index values suggest downward migration of metal that is likely to contaminate groundwater. This calls for urgent remediation so that the ill effects of As contamination can be minimized.

  7. Late Quaternary transgressive large dunes on the sediment-starved Adriatic shelf

    Science.gov (United States)

    Correggiari, A.; Field, M.E.; Trincardi, F.

    1996-01-01

    The Adriatic epicontinental basin is a low-gradient shelf where the late-Quaternary transgressive systems tract (TST) is composed of thin parasequences of backbarrier, shoreface and offshore deposits. The facies and internal architecture of the late-Quaternary TST in the Adriatic epicontinental basin changed consistently from early transgression to late transgression reflecting: (1) fluctuations in the balance between sediment supply and accommodation increase, and (2) a progressive intensification of the oceanographic regime, driven by the transgressive widening of the basin to as much as seven times its lowstand extent. One of the consequences of this trend is that high-energy marine bedforms such as sand ridges and sand waves characterize only areas that were flooded close to the end of the late-Quaternary sea-level rise, when the wind fetch was maximum and bigger waves and stronger storm currents could form. We studied the morphology, sediment composition and sequence-stratigraphical setting of a field of asymmetric bedforms (typically 3 m high and 600 m in wavelength) in 20-24 m water depth offshore the Venice Lagoon in the sediment-starved North Adriatic shelf. The sand that forms these large dunes derived from a drowned transgressive coastal deposit reworked by marine processes. Early cementation took place over most of the dune crests limiting their activity and preventing their destruction. Both the formation and deactivation of this field of sand dunes occurred over a short time interval close to the turn-around point that separates the late-Quaternary sea-level rise and the following highstand and reflect rapid changes in the oceanographic regime of the basin.

  8. Shift in detrital sedimentation in the eastern Bay of Bengal during the late Quaternary

    Indian Academy of Sciences (India)

    C Prakash Babu; J N Pattan; K Dutta; N Basavaiah; G V Ravi Prasad; D K Ray; P Govil

    2010-06-01

    Down-core variations of granulometric, geochemical and mineral magnetism of a 70-cm long sediment core retrieved from the eastern Bay of Bengal abyssal region were studied to understand sedimentation pattern and sediment provenance during the last ∼12 kyr BP. Based on down-core physical and elemental variations, three units were identified: unit 3 (70–43 cm) is a ∼30 cm thick clayey silt organic carbon-rich (0.5–0.92%) turbidite probably delivered by the Brahmaputra River during the late Quaternary period. Units 2 (43–24 cm) and 1 (24–0 cm) represent enhanced and reduced supply of coarse-grained detrital sediments from the Ganges River during early and late Holocene period, respectively. Increased terrigenous supply dilutes calcium carbonate (CaCO3) and biogenic elements (P, Ba and Cu) in units 3 and 2. On the contrary, a reduction in detrital input enhances CaCO3 and biogenic elements in unit 1. Lithogenic elements (Ti, Al, K and Rb) and shale-normalized REE patterns in all three units suggest terrigenous source. The shift in provenance from the Brahmaputra to the Ganges derived sediments is evident by a sharp increase in sediment grain size, increased concentration and grain size assemblages of magnetic minerals, lithogenic elements concentration and Lan/Ybn ratio. This study highlights terrigenous dilution on biogenic sedimentation in the eastern Bay of Bengal sediments.

  9. Physicochemistry and Mineralogy of Storm Dust and Dust Sediment in Northern China

    Institute of Scientific and Technical Information of China (English)

    刘蔚; 冯起; 王涛; 张艳武; 施建华

    2004-01-01

    Dust sediments collected from 1995 to 1998 in Beijing, Dunhuang, Inner Mongolia, Kashi, the Kunlun Mountains, Lanzhou, Ningxia, the Taklimakan Desert, and Xi'an, China, were characterized in terms of their physical, chemical, and mineralogical properties. Most aerosols and dust analysed ranged in texture from silty clay to clay loam. Their median particle diameters (Mds) generally ranged between 5 to 63μm,coinciding with those of loess from central China and the finest sand from northwestern China. The dust sediments were characterized by a predominance of SiO2 and Al2O3, followed by K2O. Their SiO2/Al2O3and K2O/SiO2 molar ratios ranged from 5.17 to 8.43 and from 0.009 to 0.0368, respectively. The mass concentration spectrum during a dust storm showed a single peak, rather than the triple peak generally observed under clear sky conditions. The dominant minerals were chlorite, illite, calcite, and dolomite.These physical, chemical, and mineralogical properties were consistent with those of aeolian soils and loess in western and central China. The results suggest that aerosols and fine-gained fractions of dust sediments collected in northern China are mainly composed of soil material transported from the arid and semiarid regions of China and Mongolia by prevailing winds. The rate of deposition and properties of dust falling on eastern China were strongly influenced by meteorological conditions, season, latitude, longitude, and altitude of the sampling sites.

  10. Mineralogical correlation of surficial sediment from area drainages with selected sedimentary interbeds at the Idaho National Engineering Laboratory, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomay, R.C.

    1990-08-01

    Ongoing research by the US Geological Survey at the INEL involves investigation of the migration of radioactive elements contained in low-level radioactive waste, hydrologic and geologic factors affecting waste movement, and geochemical factors that influence the chemical composition of the waste. Identification of the mineralogy of the Snake River Plain is needed to aid in the study of the hydrology and geochemistry of subsurface waste disposal. The US Geological Surveys project office at the Idaho National Engineering Laboratory, in cooperation with the US Department of Energy, used mineralogical data to correlate surficial sediment samples from the Big Lost River, Little Lost River, and Birch Greek drainages with selected sedimentary interbed core samples taken from test holes at the RWMC (Radioactive Waste Management Complex), TRA (Test Reactors Area), ICPP (Idaho Chemical Processing Plant), and TAN (Test Area North). Correlating the mineralogy of a particular present-day drainage area with a particular sedimentary interbed provides information on historical source of sediment for interbeds in and near the INEL. Mineralogical data indicate that surficial sediment samples from the Big Lost River drainage contained a larger amount of feldspar and pyroxene and a smaller amount of calcite and dolomite than samples from the Little Lost River and Birch Creek drainages. Mineralogical data from sedimentary interbeds at the RWMC, TRA, and ICPP correlate with surficial sediment of the present-day big Lost River drainage. Mineralogical data from a sedimentary interbed at TAN correlate with surficial sediment of the present-day Birch Creek drainage. 13 refs., 5 figs., 3 tabs.

  11. Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece

    Directory of Open Access Journals (Sweden)

    K.G. PEHLIVANOGLOU

    2004-06-01

    Full Text Available The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite. The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral

  12. Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece

    Directory of Open Access Journals (Sweden)

    K.G. PEHLIVANOGLOU

    2012-12-01

    Full Text Available The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite. The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral

  13. PERMEABILITY AND CONSOLIDATION OF SEDIMENT MIXTURES AS FUNCTION OF SAND CONTENT AND CLAY MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The current study is the first step in a systematic experimental research on the erosion behaviour of sand-mud mixtures. It concerns the effect of a varying sand content and clay mineralogy on the porosity, structure, strength and permeability of artificially generated sediment mixtures. The permeability of a sediment mixture is an especially significant parameter concerning the type of erosion that occurs. It determines ifthe erosion of the bed is either a drained or an undrained process,respectively indicating surface erosion or mass erosion. Measurements on various mixtures concerning the consolidation coefficient and the permeability have been executed. Results show a distinct transition of behaviour between a sand-silt dominated network structure and a clay-water matrix. The occurrence of these two types of structures appears to depend on the porosity of the volume fraction of sand related to silt, which is, therefore, an important parameter concerning the type of erosion. Finally, the study provides a valuable data set that can be used as a reference for following stages of this research on the erosion behaviour of natural cohesive sediments.

  14. The mineralogy of suspended matter, fresh and Cenozoic sediments in the fluvio-deltaic Rhine–Meuse–Scheldt–Ems area, the Netherlands: An overview and review

    NARCIS (Netherlands)

    Griffioen, J.; Klaver, G.; Westerhoff, W.E.

    2016-01-01

    Minerals are the building blocks of clastic sediments and play an important role with respect to the physico-chemical properties of the sediment and the lithostratigraphy of sediments. This paper aims to provide an overview of the mineralogy (including solid organic matter) of sediments as well as s

  15. The mineralogy of suspended matter, fresh and Cenozoic sediments in the fluvio-deltaic Rhine–Meuse–Scheldt–Ems area, the Netherlands: An overview and review.

    NARCIS (Netherlands)

    Griffioen, J.; Klaver, G.; Westerhoff, W.E.

    2016-01-01

    Minerals are the building blocks of clastic sediments and play an important role with respect to the physico-chemical properties of the sediment and the lithostratigraphy of sediments. This paper aims to provide an overview of the mineralogy (including solid organic matter) of sediments as well as s

  16. Significant differences in late Quaternary bedrock erosion and transport

    DEFF Research Database (Denmark)

    Andrews, John; Bjørk, Anders Anker; Eberl, Dennis;

    2015-01-01

    We use quantitative X-ray diffraction to determine the mineralogy of late Quaternary marine sediments from the West and East Greenland shelves offshore from early Tertiary basalt outcrops. Despite the similar basalt outcrop area (60 000–70 000 km2), there are significant differences between East ...

  17. A semiquantitative X-ray diffraction method to determine mineral composition in stream sediments with similar mineralogy

    Science.gov (United States)

    Webster, D.M.

    1989-01-01

    A semiquantitative X-ray diffraction procedure has been developed that can be used to acquire reproducible mineralogic data from geographically unrelated stream-sediment samples having similar mineralogy. Weight percentages for quartz, total-feldspar, and total-clay can be determined by direct comparison of intensities with standard-mineral mixtures of known weight percent. Matrix effects and mass-absorption differences are circumvented by taking the ratio of peak-intensity, in counts per second, for quartz relative to that of other minerals being quantified. Mineral percentages generally are reproducible to within 10 percent.

  18. Late Quaternary stratigraphy and sedimentation patterns in the western Arctic Ocean

    Science.gov (United States)

    Polyak, L.; Bischof, J.; Ortiz, J.D.; Darby, D.A.; Channell, J.E.T.; Xuan, C.; Kaufman, D.S.; Lovlie, R.; Schneider, D.A.; Eberl, D.D.; Adler, R.E.; Council, E.A.

    2009-01-01

    Sediment cores from the western Arctic Ocean obtained on the 2005 HOTRAX and some earlier expeditions have been analyzed to develop a stratigraphic correlation from the Alaskan Chukchi margin to the Northwind and Mendeleev-Alpha ridges. The correlation was primarily based on terrigenous sediment composition that is not affected by diagenetic processes as strongly as the biogenic component, and paleomagnetic inclination records. Chronostratigraphic control was provided by 14C dating and amino-acid racemization ages, as well as correlation to earlier established Arctic Ocean stratigraphies. Distribution of sedimentary units across the western Arctic indicates that sedimentation rates decrease from tens of centimeters per kyr on the Alaskan margin to a few centimeters on the southern ends of Northwind and Mendeleev ridges and just a few millimeters on the ridges in the interior of the Amerasia basin. This sedimentation pattern suggests that Late Quaternary sediment transport and deposition, except for turbidites at the basin bottom, were generally controlled by ice concentration (and thus melt-out rate) and transportation distance from sources, with local variances related to subsurface currents. In the long term, most sediment was probably delivered to the core sites by icebergs during glacial periods, with a significant contribution from sea ice. During glacial maxima very fine-grained sediment was deposited with sedimentation rates greatly reduced away from the margins to a hiatus of several kyr duration as shown for the Last Glacial Maximum. This sedimentary environment was possibly related to a very solid ice cover and reduced melt-out over a large part of the western Arctic Ocean.

  19. Mineralogy and arsenic mobility in arsenic-rich Brazilian soils and sediments

    Science.gov (United States)

    de Mello, J.W.V.; Roy, W.R.; Talbott, J.L.; Stucki, J.W.

    2006-01-01

    Background. Soils and sediments in certain mining regions of Brazil contain an unusually large amount of arsenic (As), which raises concerns that mining could promote increased As mobility, and thereby increase the risks of contaminating water supplies. Objectives. The purpose of t his study was to identify the most important factors governing As mobility in sediments and soils near three gold-mining sites in the State of Minas Gerais, Brazil. Methods. Surface and sub-surface soil samples were collected at those sites and characterized by chemical and mineralogical analyses. Oxalate (Feo) and citrate-bicarbonate-dithionite (Fed) iron contents were determined by atomic absorption spectroscopy (AAS). Arsenic mobilization was measured after incubating the samples in a 2.5 mM CaCl2 solution under anaerobic conditions for 1, 28, 56, 84, or 112 days. The solution concentrations of As, Fe, and Mn were then measured by inductively coupled plasma-mass spectrometry (ICP-MS) and AAS, respectively. Results and Discussion. Results indicated that As mobilization is largely independent of both the total As and the Feo/Fed ratio of the solid phase. Soluble As is roughly controlled by the Fe (hydr)oxide content of the soil, but a closer examination of the data revealed the importance of other highly weathered clay minerals and organic matter. Large amounts of organic matter and a low iron oxide content should favor As leaching from soils and sediments. Under reducing conditions, As is mobilized by the reductive dissolution of Fe and/or Mn oxides. However, released As may be readsorbed depending on the sorptive properties of the soil. Gibbsite is particularly effective in adsorbing or readsorbing As, as is the remaining unreduced fraction of the iron (hydr)oxides. Conclusion and Outlook. In general, low soluble As is rel ated to the presence of gibbsite, a large amount of iron oxides, and a lack of organic matter in the solid phase. This has environmental significance because

  20. Application of DOI index to analysis of selected examples of resistivity imaging models in Quaternary sediments

    Directory of Open Access Journals (Sweden)

    Glazer Michał

    2014-12-01

    Full Text Available Interpretation of resistivity cross sections may be in many cases unreliable due to the presence of artifacts left by the inversion process. One way to avoid erroneous conclusions about geological structure is creation of Depth of Investigation (DOI index maps, which describe durability of prepared model with respect to variable parameters of inversion. To assess the usefulness of this interpretation methodology in resistivity imaging method over quaternary sediments, it has been used to one synthetic data set and three investigation sites. Two of the study areas were placed in the Upper Silesian Industrial District region: Bytom - Karb, Chorzów - Chorzow Stary; and one in the Southern Pomeranian Lake District across Piława River Valley. Basing on the available geological information the results show high utility of DOI index in analysis of received resistivity models, on which areas poorly constrained by data has been designated.

  1. Pulsed IRSL: A stable and fast bleaching luminescence signal from feldspar for dating Quaternary sediments

    DEFF Research Database (Denmark)

    Tsukamoto, Sumiko; Kondo, Reisuke; Lauer, Tobias

    2017-01-01

    Elevated temperature post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR) dating method using feldspar has led to a significant advancement in dating Quaternary sediments, as this signal has been shown to be stable on geological time scales. In comparison to the conventional IRSL...... fading, when the signal is recorded during the off-time of LED stimulation pulses. In this study, we compare the signal bleachability, thermal and athermal stability, and age estimates derived using different measurement methods, i.e., pulsed IRSL measured at 50 °C (pulsed IR50; subscripts refers...... and tephrochronology. We observe that under exposure to solar simulator, the pulsed IR50 signal bleaches as rapidly as the CW IR50, and much more rapidly than the pIRIR signals. Furthermore, the pulsed IR50 signal is also as stable as the pIRIR signals, especially when the middle part of the decay curve is used...

  2. Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

    Directory of Open Access Journals (Sweden)

    M.-C. Ciobanu

    2012-09-01

    Full Text Available An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion. Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG, within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG and Halobacteria within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence

  3. Thermodynamic simulation on mineralogical composition of CaO-SiO2-Al2O3-MgO quaternary slag system.

    Science.gov (United States)

    Liu, Chao; Zhang, Yu-Zhu; Li, Jie; Li, Jun-Guo; Kang, Yue

    2016-01-01

    It is necessary to elucidate the crystallization thermodynamic of mineralogical phases during the cooling process of the molten BFS with different chemical composition, because the high-melting point mineral phase maybe crystallized during the fiber forming and thereafter cooling process. Thermodynamic calculation software FactSage6.4 and the hot remelting experiments were performed to explore the influence of basicity, Al2O3 content and MgO content on the crystallization of mineralogical components and their transformation. The results showed that the main mineralography of the CaO-SiO2-Al2O3-MgO quaternary slag system was melilite, and a certain amount of anorthite and calcium metasilicate. The crystallographic temperature of melilite is increased with the increasing of basicity, MgO and Al2O3 content, which has a significant impact on the utilization performance of the mineral wool prepared with the hot blast furnace slag directly. With the increasing of basicity, there was a tendency that crystallographic amount of melilite increased to the summit and then declined, while the amount of anorthite and calcium metasilicate decreased consistently. Finally, these two mineralogical components could be replaced by magnesium rhodonite and spinel with the increasing of basicity. When the basicity and MgO content were 1.0 and 9 %, the crystallographic mass ratio of melilite and anorthite increased, while that of calcium silicate declined, and replaced by spinel finally with the increasing of Al2O3 content. When the basicity and Al2O3 content were 1.0 and 13 %, the crystallographic mass ratio of melilite increased, while that of anorthite and calcium silicate declined, and replaced by pyroxene and spinel with the increasing of MgO content. To decline fiberization temperature of the melt BFS, the basicity, MgO and Al2O3 content should be decreased during the modification process of chemical composition, because the crystallization temperature of the primary crystalline

  4. Quaternary sedimentation and active faulting along the Ecuadorian shelf: preliminary results of the ATACAMES Cruise (2012)

    Science.gov (United States)

    Michaud, F.; Proust, J. N.; Collot, J. Y.; Lebrun, J. F.; Witt, C.; Ratzov, G.; Pouderoux, H.; Martillo, C.; Hernández, M. J.; Loayza, G.; Penafiel, L.; Schenini, L.; Dano, A.; Gonzalez, M.; Barba, D.; De Min, L.; Ponce, G.; Urresta, A.; Calderon, M.

    2015-03-01

    Selected high-resolution seismic-reflection profiles and multibeam bathymetry acquired along the convergent Ecuador margin during the ATACAMES cruise on onboard the R/V L'Atalante (Jan.15-Feb.18, 2012) allow a preliminary evaluation of the neotectonic development and stratigraphic evolution of the margin based on the sismo-stratigraphic analysis of Quaternary sediment preserved on the margin shelf and upper slope. We present three major preliminary results. (1) The evolution of the Esmeraldas, Guayaquil and Santa Elena canyons. The head of the Esmeraldas canyon is the location of a continuous significant sediment transport. The Guayaquil canyon shows several episodes of deposition and incision. Aggrading sedimentation pattern in the canyon records several changes in relative sea-level. The subsidence of the Gulf of Guayaquil probably contributes to the good preservation of the canyon filling stages. The Santa Elena canyon is controlled by a SW-NE trending normal fault. (2) Variations of sediment accumulation and relative vertical motions are shown along-strike the shelf edge. Offshore the uplifted Manta peninsula, a pronounced subsidence of the shelf edge is documented by sedimentary clinoforms that have deposited in a morphological reentrant, and have migrated upslope testifying of a local subsidence meanwhile the adjacent La Plata Island area underwent uplift. In the Esmeraldas canyon area, a local uplift of the shelf is documented. (3) Two neotectonic fault systems with a possible transcurrent component are imaged across the shelf edge and upper margin slope offshore Jama, and Cape Galera. This possible transcurrent motion could be related to the reactivation of ancient faults of the upper plate by the subduction. These preliminary results indicate that the ATACAMES data set has a strong potential to evaluate the spatial and temporal contribution of tectonic and climate changes on the structural development and stratigraphic evolution of the Ecuador continental

  5. Geochemistry and mineralogy of recent sediments of Guanabara Bay (NE sector and its major rivers - Rio de Janeiro State - Brazil

    Directory of Open Access Journals (Sweden)

    FARIA MARCIA DE MELO

    2001-01-01

    Full Text Available Geochemical and clay mineralogical studies of bottom sediments collected along the Macacu and Caceribu rivers and Guanabara Bay were carried out in order to investigate the relationship between major source areas and recent sediments of the bay. Clay mineralogy includes different groups with selective distribution conditioned by geomorphic features and depositional settings. Micaceous clay minerals are abundant near parent rock in the upper course, whereas kaolinite derived from varied sources is gradually concentrated towards the estuary. In the Guanabara Bay, kaolinite accumulates near river mouths, while micaceous clay minerals are converted into mixed layers in the estuary. Analyses of heavy metal contents reveal higher levels of Zn and Cu in sediments of the bay than in river sediments. Profiles along rivers indicate a downstream decrease of heavy metals, whereas in the bay geochemical trends display greater variations. In general river mouth sediments present the lowest concentrations. At the north and east of Paquetá Island anomalous areas with the highest heavy metal contents occur. Cu tends to concentrate in < 2mum grain-size fraction and indicates an association with micaceous clay minerals in the upper river course. However, Cu retention seems to be further controlled by other components of bottom sediments due to changes in physical and chemical conditions of the estuarine environment. Zn shows unstable behavior along the rivers and concentrates in the bay. Pb displays small variations from river to bay sediments, and accumulates mainly in the < 63mum grain-size fraction without any association with clay mineral. Geoaccumulation indexes of Cu, Pb and Zn classify the study area as unpolluted in both studied rivers and in the NE sector of the bay, though the enrichment factors are higher in the bay. The study does not indicate those rivers as major sources of heavy metal pollution to the bay.

  6. Plio-Quaternary sedimentation in the Mozambique Channel and in the Zambezi Fan

    Science.gov (United States)

    Fierens, Ruth; Droz, Laurence; Toucanne, Samuel; Jorry, Stephan; Raisson, François

    2017-04-01

    The classical stratigraphic framework stating minimum land-to-sea transfers during periods of high relative sea-level is challenged by marine sedimentary systems in regions where climate (low latitude, monsoon-type) is dominated by the 23-ky cyclicity. Known turbidite systems at the lowest latitudes, like the Nile and Bengal systems (Ducassou et al., 2009; Weber et al., 1997) show that the supply of sediments to the deep oceanic domain could persist during relative high sea-level periods. But turbidite systems at low-latitudes still remain poorly understood. In this work, we use the Zambezi turbidite system as a case study to develop our understanding of the reactivity of deep marine sedimentary systems and land-sea transfers to low-latitude climate variability. The Zambezi Plio-Quaternary turbidite system ( 2000 km long x 500 km wide) is located within the Mozambique Channel (Indian Ocean; 11°-30°S), separating Madagascar from the African continent, in a context of high hydronamic conditions. An extensive dataset acquired strategically along the turbidite system was obtained within the scope of the PAMELA project (scientific project leaded by Ifremer and TOTAL in collaboration with Université de Bretagne Occidentale, Université Rennes 1, Université Pierre and Marie Curie, CNRS et IFPEN) and includes multibeam bathymetry, seismic reflection data and sediment cores. Preliminary results of morphological, seismic and sedimentological study suggest that this turbidite system in the Mozambique Channel is particular: i) The Zambezi Valley currently appears to be dominated by erosional or vacuity process over its entire length, which is observed within the valley as well as on the flanks; ii) Only two restricted zones of tubiditic deposition are identified; iii) The sedimentary record of the last 375 ky shows few turbidites that occurs both during glacial and interglacial periods, with a rate of recurrence of several tens of thousands of years. Additional

  7. Quaternary clay mineralogy in the northern South China Sea (ODP Site 1146)--Implications for oceanic current transport and East Asian monsoon evolution

    Institute of Scientific and Technical Information of China (English)

    LIU Zhifei(刘志飞); Alain Trentesaux; Steven C. Clemens; WANG Pinxian(汪品先)

    2003-01-01

    Measurement of clay mineralogy at ODP Site 1146 in the northern South China Sea (SCS) indicates that illite, chlorite, and kaolinite contents increased during glacials and smectite content increased during interglacials. The smectite/(illite+chlorite) ratio and the smectite abundance were determined as mineralogical indicators for the East Asian monsoon evolution. At a 10 ka timescale, prevailing southeasterly surface oceanic currents during interglacials transported more smectite from the south and east areas to the north, showing a strengthened summer monsoon circulation, whereas dominated counter-clockwise surface currents during glacials carried more illite and chlorite from Taiwan as well as from the Yangtze River via the Luzon Strait to the northern SCS, indicating a strongly intensified winter monsoon. Based on a 100 ka timescale, a linear correlation between the smectite/(illite+chlorite) ratio and the sedimentation rate reflects that the winter monsoon has prevailed in the northern SCS in the intervals 2000-1200 ka and 400-0 ka and the summer monsoon did the same in the interval 1200-400 ka. The evolution of the summer monsoon provides an almost linear response to the summer insolation of Northern Hemisphere, implying an astronomical forcing of the East Asian monsoon evolution.

  8. Lithostratigraphic development and neotectonic significance of the Quaternary sediments along the Kachchh Mainland Fault (KMF) zone, western India

    Indian Academy of Sciences (India)

    V Chowksey; D M Maurya; Parul Joshi; N Khonde; Archana Das; L S Chamyal

    2011-12-01

    The Kachchh Mainland Fault (KMF) is a major E–W trending seismically active fault of the Kachchh palaeorift basin whose neotectonic evolution is not known. The present study deals with the eastern part of the KMF zone where the fault is morphologically expressed as steep north facing scarps and is divisible into five morphotectonic segments. The Quaternary sediments occurring in a narrow zone between the E–W trending KMF scarps and the flat Banni plain to the north are documented. The sediments show considerable heterogeneity vertically as well as laterally along the KMF zone. (The Quaternary sediments for a northward sloping and are exposed along the north flowing streams which also show rapid decrease in the depth of incision in the same direction.) The deposits, in general, comprise coarse as well as finer gravelly deposits, sands and aeolian and fluvial miliolites. The Quaternary sediments of the KMF zone show three major aggradation phases. The oldest phase includes the colluvio-fluvial sediments occurring below the miliolites. These deposits are strikingly coarse grained and show poor sorting and large angular clasts of Mesozoic rocks. The sedimentary characteristics indicate deposition, dominantly by debris flows and sediment gravity flows, as small coalescing alluvial fans in front of the scarps. These deposits suggest pre-miliolite neotectonic activity along the KMF. The second aggradation phase comprises aeolian miliolites and fluvially reworked miliolites that have been previously dated from middle to late Pleistocene. The youngest phase is the post-miliolite phase that includes all deposits younger than miliolite. These are represented by comparatively finer sandy gravels, gravelly sands and sand. The sediment characteristics suggest deposition in shallow braided stream channels under reduced level of neotectonic activity along the KMF during post-miliolite time evidenced by vertical dips of miliolites and tilting of gravels near the scarps. The

  9. Mineralogy, chemistry, and grain size composition of recent sediments in the northern Tyrrhenian Sea: Contribution to the study of sediment transport and distribution

    Science.gov (United States)

    Leoni, Leonardo; Sartori, Franco; Saitta, Maurizio; Damiani, Vincenzo; Ferretti, Ornella; Viel, Monique

    1991-01-01

    As a contribution to an environmental study on Tuscany's marine shelf, textural, mineralogical, and chemical characteristics of recent sediments in the northern Tyrrhenian Sea between Elba Island and Livorno have been analyzed. The data provide clear information on sediment sources and movement patterns. The main sediment source appears to be the Cecina River; very subordinate is the contribution of the Fine River. As to sediment movement patterns, the surveyed basin appears to be divided into two subbasins: (1) a greater, southern subbasin, bounded by Tuscany mainland, Elba Island and Elba Ridge, and Capraia Isle, and Vada Shoals; and (2) a smaller, northern subbasin, enclosed between Vada Shoals and Meloria Shoals (off Livorno port). In the former the coarse-grade Cecina River sediments are transported southward along most of the mainland coast by littoral drift and coastal current; a northward flowing countercurrent seems to be active only in the southernmost part. Silts and clays are distributed in concentric belts around basin's central part, being transported mainly by slow circular water movements. In the marginal western zone, very little terrigenous influx is coupled with a high biologic productivity, and biogenic debris sedimentation prevails there. In the northern subbasin the sediment contribution from Fine River is more appreciable. Here the environmental energies are very low and the coarse sediments are restricted to a few small pocket beaches where they are deposited by local creeks. Most of the subbasin area is occupied by sapropelitic muds, again distributed by slow small-scale gyres.

  10. Occurrence of pesticides in groundwater and sediments and mineralogy of sediments and grain coatings underlying the Rutgers Agricultural Research and Extension Center, Upper Deerfield, New Jersey, 2007

    Science.gov (United States)

    Reilly, Timothy J.; Smalling, Kelly L.; Meyer, Michael T.; Sandstrom, Mark W.; Hladik, Michelle L.; Boehlke, Adam R.; Fishman, Neil S.; Battaglin, William A.; Kuivila, Kathryn M.

    2014-01-01

    Water and sediment samples were collected from June through October 2007 from seven plots at the Rutgers Agricultural Research and Extension Center in Upper Deerfield, New Jersey, and analyzed for a suite of pesticides (including fungicides) and other physical and chemical parameters (including sediment mineralogy) by the U.S. Geological Survey. Plots were selected for inclusion in this study on the basis of the crops grown and the pesticides used. Forty-one pesticides were detected in 14 water samples; these include 5 fungicides, 13 herbicides, 1 insecticide, and 22 pesticide degradates. The following pesticides and pesticide degradates were detected in 50 percent or more of the groundwater samples: 1-amide-4-hydroxy-chorothalonil, alachlor sulfonic acid, metolachlor oxanilic acid, metolachlor sulfonic acid, metalaxyl, and simazine. Dissolved-pesticide concentrations ranged from below their instrumental limit of detection to 36 micrograms per liter (for metolachlor sulfonic acid, a degradate of the herbicide metolachlor). The total number of pesticides found in groundwater samples ranged from 0 to 29. Fourteen pesticides were detected in sediment samples from continuous cores collected within each of the seven sampled plots; these include 4 fungicides, 2 herbicides, and 7 pesticide degradates. Pesticide concentrations in sediment samples ranged from below their instrumental limit of detection to 34.2 nanograms per gram (for azoxystrobin). The total number of pesticides found in sediment samples ranged from 0 to 8. Quantitative whole-rock and grain-coating mineralogy of sediment samples were determined by x-ray diffraction. Whole-rock analysis indicated that sediments were predominantly composed of quartz. The materials coating the quartz grains were removed to allow quantification of the trace mineral phases present.

  11. Estimated Altitude of the Consolidated Rock Surface Underlying Quaternary Sediments of the Wood River Valley aquifer system, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is the estimated altitude of the consolidated rock surface underlying Quaternary sediment of the Wood River Valley aquifer system. This surface is...

  12. Mineralogy, chemistry, and grain size composition of recent sediments in the northern Tyrrhenian Sea: Contribution to the study of sediment transport and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, L.; Sartori, F.; Saitta, M. (Univ. of Pisa (Italy)); Damiani, V.; Ferretti, O.; Viel, M. (ENEA, La Spezia (Italy))

    As a contribution to an environmental study on Tuscany's marine shelf, textural, mineralogical, and chemical characteristics of recent sediments in the northern Tyrrhenian Sea between Elba Island and Livorno have been analyzed. The data provide clear information on sediment sources and movement patterns. The main sediment sources and movement patterns. The main sediment source appears to be the Cecina River; very subordinate is the contribution of the Fine River. As to sediment movement patterns, the surveyed basin appears to be divided into two subbasins: (1) a greater, southern subbasin, bounded by Tuscany mainland, Elba Island and Ridge, and Capraia Isle, and Vada Shoals; and (2) a smaller, northern subbasin, enclosed between Vada Shoals and Meloria Shoals (off Livorno port). In the former the coarse-grade Cecina River sediments are transported southward along most of the mainland coast by littoral drift and coastal current; a northward flowing counter-current seems to be active only in the southernmost part. Silts and clays are distributed in concentric belts around basin's central part, being transported mainly by slow circular water movements. In the marginal western zone, very little terrigenous influx is coupled with a high biologic productivity, and biogenic debris sedimentation prevails there. In the northern subbasin the sediment contribution from Fine River is more appreciable. Here the environmental energies are very low and the coarse sediments are restricted to a few small pocket beaches where they are deposited by local creeks. Most of the subbasin area is occupied by sapropelitic muds, again distributed by slow small-scale gyres.

  13. Quaternary Branched Alkanes: A Geologic Proxy for Biological Sulfur Oxidation in Pleistocene Coastal Sediments of California

    Science.gov (United States)

    Zinniker, D. A.; Green Nylen, N.; Moldowan, J. M.; Denisevich, P.; Ingle, J. C.

    2003-12-01

    Branched alkanes with quaternary substituted carbon atoms (QBAs) have been identified in two Pleistocene sedimentary sequences exposed along the California coastline. While these compounds have yet to be isolated from cultured microorganisms, a growing body of evidence points towards their origin as membrane components of colorless sulfur oxidizing bacteria (Kenig et al., 2002). This evidence includes an association with sulfide minerals, an association with environments or paleoenvironments with sharp sulfide:oxygen gradients, a positive correlation with the bacterial lipid diploptene, and (in this study) a positive correlation between the abundance of QBAs and the abundance of elemental sulfur in organic extracts. The wide distribution of QBAs in modern environments (deep sea hydrothermal systems, Arctic shelf sediments, and sediment traps from an oligotrophic marine site) may implicate chemoautotrophic and/or chemoorganotrophic members of the epsilon Proteobacteria as the source of QBAs. Sediments of the neritic to nonmarine Merced Formation near San Francisco and the bathyal to neritic Rio Dell Formation north of Cape Mendocino have been found to contain QBAs - predominantly 5,5-diethylalkanes and 2,2-dimethylalkanes. 5,5-diethylalkanes were identified by comparison of their spectra and elution time with published reports. 2,2-dimethylalkanes were identified through the chemical synthesis of authentic standards. In both sedimentary sequences, QBAs vary in abundance by more than two orders of magnitude over glacial-interglacial cycles. This variation appears to be crudely correlated with the abundance of elemental sulfur. In the Rio Dell Formation QBAs show an inverse correlation with the neritic benthic foraminifer biofacies as well as trace and macrofossil assemblages indicative of higher benthic oxygen concentrations. The occurrence of QBAs in shelf deposits of the lower Merced Formation supports previous interpretations that suggest a restricted basin

  14. Sources and cycling of mercury in the paleo Arctic Ocean from Hg stable isotope variations in Eocene and Quaternary sediments

    Science.gov (United States)

    Gleason, J. D.; Blum, J. D.; Moore, T. C.; Polyak, L.; Jakobsson, M.; Meyers, P. A.; Biswas, A.

    2017-01-01

    Mercury stable isotopic compositions were determined for marine sediments from eight locations in the Arctic Ocean Basin. Mass dependent fractionation (MDF) and mass independent fractionation (MIF) of Hg stable isotopes were recorded across a variety of depositional environments, water depths, and stratigraphic ages. δ202Hg (MDF) ranges from -2.34‰ to -0.78‰; Δ199Hg (MIF) from -0.18‰ to +0.12‰; and Δ201Hg (MIF) from -0.29‰ to +0.05‰ for the complete data set (n = 33). Holocene sediments from the Chukchi Sea and Morris Jesup Rise record the most negative Δ199Hg values, while Pleistocene sediments from the Central Arctic Ocean record the most positive Δ199Hg values. The most negative δ202Hg values are recorded in Pleistocene sediments. Eocene sediments (Lomonosov Ridge) show some overlap in their Hg isotopic compositions with Quaternary sediments, with a sample of the Arctic Ocean PETM (56 Ma) most closely matching the average Hg isotopic composition of Holocene Arctic marine sediments. Collectively, these data support a terrestrially-dominated Hg source input for Arctic Ocean sediment through time, although other sources, as well as influences of sea ice, atmospheric mercury depletion events (AMDEs), and anthropogenic Hg (in core top samples) on Hg isotopic signatures must also be considered.

  15. Mineralogical and geochemical characters of surface sediments from the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.

    and siliceous sediments of the northern part of the basin indicate the influence of continental influx. This influence, however, decreases in the southern part of the basin where smectite is predominant, indicating volcanic input. The basinal sediments...

  16. Chemical and mineralogical proxies of erosion episodes in the dried lake sediments (Amik Lake, Southern Turkey): paleoenvironmental implications

    Science.gov (United States)

    El Ouahabi, Meriam; Hubert-Ferrari, Aurélia; Lebeau, Héléne; Fagel, Nathalie; Vander Auwera, Jacquelinec; Karabacak, Volkan; Schmidt, Sabine

    2016-04-01

    The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its golden age. The basin also sustained a high seismic activity (M≥7) as it is a releasing step-over along the Dead Sea Fault. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. High resolution of mineralogical (XRD) and geochemical (XRF) analyses were performed. Quantitative mineralogical phases of sediments by the Rietveld method were computed using Topaz software. The age of the record is constrained combining radionuclide and radiocarbon dating, and checked using the correlation between the earthquake history and rapidly deposited layer identified. A high sedimentation rate of 0.12 cm/yr was inferred at the coring site. The 4000 years old record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand leaded to punctual dryings of the lake at the end of the Bronze/Iron transition marked by the collapse of the Hittite Empire and during the Dark ages. At that time, the riverine was carrying a large terrigenous input linked to strong soil erosion related to deforestation, exploitation of mineral resources and the beginning of upland cultivation. During the Roman Period and in the later periods, upland soils were partly depleted and the riverine system completely transformed by channelization that leaded to a mashification of the Amik Basin. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation

  17. Wrench tectonics control on Neogene-Quaternary sedimentation along the Mid-Hungarian Mobile Belt

    Science.gov (United States)

    Pogacsas, Gyorgy; Juhász, Györgyi; Mádl-Szőnyi, Judit; Simon, Szilvia; Lukács, Szilveszter; Csizmeg, János

    2010-05-01

    The Neogene Pannonian basin is underlain by a large orogenic collage which is built up by several tectonostratigraphic terrains. The basement of the Pannonian Basin became imbricate nappes during the Cretaceous Alpine collision. Nappes of Late Cretaceous in age have been proven below the Great Hungarian Plain (Grow et al 1994). The boundary of the two main terrains, the northwestern ALCAPA (Alpine-Carpathian-Pannonian) and the southeastern TISZA, is the Mid-Hungarian Mobile Belt. It is the most significant neotectonic zone of the Pannonian Basin. The structural analysis of the middle section of the Mid-Hungarian Mobile Belt was carried out on a 120km x 50km area, between the Danube and the Tisza river, on the basis of interpretation of seismic data. The structural analysis of the Neogene-Quaternary sediments was supported by sequence stratigraphic interpretation of seismic, well log and core-sample data. Regional seismic profiles were both oriented in the dip direction, which highlights sediment supply routes into the basin, and strike-oriented. The studied segment of the Mid-Hungarian Mobile Belt consists of several long (some ten kilometres long) strike slip fault zones. The offset lengths of the individual strike slipe faults varies between a few and a dozens of kilometres. Activity along the Mid-Hungarian Mobile Belt can be characterised by four periods, the size and shape of facies zones of each development period were controlled by tectonics: 1. During the early Miocene, the ALPACA moved eastward, bounded by sinistral strike-slipe system along its northern side and dextral strike-slipe fault system along its contact with the Southern Alps and the TISZA terrain. The largest movement took part during the Ottnangian-Karpatian (19-16.5 Ma). The TISZA unit moved northeastward over the remnant Carpathian Flysch Basin (Nemcok et al 2006). These terrains movements resulted in right lateral, convergent wide wrench along the Mid-Hungarian Mobile Belt. The ALPACA

  18. Quaternary forest and climate history of Hokkaido, Japan, from marine sediments

    Science.gov (United States)

    Igarashi, Yaeko

    Pollen data from Quaternary marine sediments deposited in central Hokkaido, northern Japan provide insight into northeast Asian vegetation and climatic changes over the last few million years. During the Early Pleistocene, coniferous forest, dominated by Picea and Cryptomeria japonica, and taiga composed of Larix and Picea developed under cool/wet and cold/dry climates, respectively. Strong climatic contrasts are inferred from Late Pleistocene interglacial and glacial pollen assemblages which precede the last glacial cycle. In the former, cool temperate broad-leaf forest, mainly composed of Fagus, reflects a warmer and wetter climate than now. In the latter, taiga similar to that now found in northern Sakhalin apparently flourished in Hokkaido. The composition of pollen assemblages correlated with Oxygen Isotope Stage 5, changed from cool temperate forest of Quercus, Ulmus and Juglans (Substage 5e), to Picea-Larix taiga (Substage 5d), cool temperate forest of Quercus and Ulmus (Substage 5c) and Picea-Abies forest (Substage 5b). Compared with present conditions, climate during Stage 5 in northern Japan apparently fluctuated from warmer/wetter to colder/drier. Taiga composed of Picea, Pinus and Larix indicating colder/dry conditions during Stage 4, was replaced by Picea-Abies forest and Picea-Larix taiga in Stage 3, suggesting relatively cool and cold/dry environments. Taiga and mixed forest with taiga and cool temperate components characterize Stage 2. Holocene forests with Juglans-Betula and Quercus-Juglans were succeeded by Picea and Abies during the early Holocene warm interval ˜7000 BP. Subsequently, Quercus-Ulmus and Abies-Alnus assemblages reflect climatic deterioration. 'Pan-mixed' forest has been developed in Hokkaido since 2000 BP.

  19. Mineralogy of Fluvio-Lacustrine Sediments Investigated by Curiosity During the Prime Mission: Implications for Diagenesis

    Science.gov (United States)

    Rampe, Elizabeth B.; Morris, R. V.; Bish, D. L.; Vaniman, D. T.; Bristow, T. F.; Chipera, S. J.; Blake, D. F.; Ming, D. W.; Farmer, J. D.; Morrison, S. M.; Treiman, A. H.; Archilles, C. N.; Crisp, J. A.; DesMarais, D. J.; Downs, R. T.; Morookian, J. M.; Sarrazin, P.; Spanovich, N.; Yen, A. S.

    2014-01-01

    The Mars Science Laboratory rover Curiosity investigated sedimentary rocks that were deposited in a diversity of fluvio-lacustrine settings. The entire science payload was employed to characterize the mineralogy and chemistry of the Sheepbed mudstone at Yellowknife Bay and the Windjana sandstone at the Kimberley. Data from the CheMin instrument, a transmission Xray diffractometer, were used to determine the quantitative mineralogy of both samples. The Sheepbed mudstone contains detrital basaltic minerals, calcium sulfates, iron oxides or hydroxides, iron sulfides, trioctahedral smectite, and amorphous material. The mineral assemblage and chemical data from APXS suggest that the trioctahedral smectite and magnetite formed authigenically as a result of alteration of olivine. The apparent lack of higher-grade phyllosilicates (e.g., illite and chlorite) and the presence of anhydrite indicate diagenesis at 50- 80 ºC. The mineralogy of the Windjana sandstone is different than the Sheepbed mudstone. Windjana contains significant abundances of K-feldspar, low- and high-Ca pyroxenes, magnetite, phyllosilicates, and amorphous material. At least two distinct phyllosilicate phases exist: a 10 Å phase and a component that is expanded with a peak at 11.8 Å. The identity of the expanded phase is currently unknown, but could be a smectite with interlayer H2O, and the 10 Å phase could be illite or collapsed smectite. Further work is necessary to characterize the phyllosilicates, but the presence of illite could suggest that Windjana experienced burial diagenesis. Candidates for the cementing agents include fine-grained phyllosilicates, Fe-oxides, and/or amorphous material. Interpretations of CheMin data from the Windjana sandstone are ongoing at the time of writing, but we will present an estimate of the composition of the amorphous material from mass balance calculations using the APXS bulk chemistry and quantitative mineralogy from CheMin.

  20. Geological provenance of Quaternary deposits from the southeastern Brazilian coast

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.M. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Campus da Praia Vermelha, 24210-346, Niteroi, R.J. (Brazil)]. E-mail: meigikos@if.uff.br; Veiga, R. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Campus da Praia Vermelha, 24210-346, Niteroi, R.J. (Brazil); Carvalho, C. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Campus da Praia Vermelha, 24210-346, Niteroi, R.J. (Brazil); Macario, K.D. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Campus da Praia Vermelha, 24210-346, Niteroi, R.J. (Brazil); Gomes, P.R.S. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Campus da Praia Vermelha, 24210-346, Niteroi, R.J. (Brazil)

    2007-05-01

    Natural gamma radiation measurements of beach sand deposits were performed with the aim of understanding the provenance and transport processes of sediments along the coastal zone of three Brazilian States. The method employs thorium, uranium and potassium as tracers of the mineralogical properties of beach sand minerals, which reflect the geological history of transport and sorting processes. A considerable positive correlation with the geological evolution of these Quaternary coastal deposits was observed.

  1. Late Quaternary evolution of the East Asian summer monsoon: Clay and magnetic mineralogical records retrieved from the northern South China Sea

    Science.gov (United States)

    Chen, Q.; Liu, Z.; Kissel, C.

    2016-12-01

    East Asian monsoon is a major component of global monsoon system. Acting as the largest marginal sea in the western Pacific, the South China Sea is a natural laboratory recording East Asian monsoon evolution. In order to reconstruct the late Quaternary evolution of the monsoon, we analyzed in details the 50.8-m-long Core MD12-3432 retrieved from the northern South China Sea at 2125 m water depth. Carbonate and magnetic stratigraphy indicates that Core MD12-3432 covers the last 400 ka. Clay mineralogical analysis was performed every 10 cm using XRD method. Bulk magnetic properties (susceptibility, NRM, ARM, and IRM) were measured on u-channel samples with a resolution of 2 cm. Cumulative log Gaussian decomposition analysis was performed on 33 high resolution IRM acquisition curves to evaluate the contribution of coercivity components. Three-axis thermal demagnetization was conducted on 14 samples to identify the nature of magnetic minerals. Clay mineral assemblage of Core MD12-3432 is dominated by smectite (23-59%) and illite (22-43%), with minor chlorite (13-27%) and kaolinite (4-13%). Because smectite is formed by rapid chemical weathering of volcanic rocks in Luzon, while illite and chlorite are primary minerals formed by physical erosion, smectite/(illite+chlorite) ratio constitutes a proxy of chemical weathering intensity. Magnetic fraction of Core MD12-3432 is composed by minerals with different coercivities, the relative proportion of which varies along the core. The high coercivity is carried by hematite and the low coercivity fraction is mainly composed by magnetite with some iron-sulphides. Luzon is the most efficient source of magnetite because of the rapid eluviation and weathering of volcanic rocks, while the Pearl River basin is the only source that produces hematite mainly through physical degradation of bedrocks. Thus, the bulk coercivity as indicated by S-ratio can serve as a proxy of chemical weathering. Both indicators, smectite

  2. LATE QUATERNARY SEISMIC SEQUENCES AND SEDIMENTATION ALONG THE COAST OFF TAISHAN,GUANGDONG,AS REVEALED BY HIGH RESOLUTION SEISMIC DATA

    Institute of Scientific and Technical Information of China (English)

    吴时国; 黄孝健

    2002-01-01

    Seismic stratigraphic analysis of 150 km of high-resolution seismic profiles (G E OPULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong pr ovided valuable information on the offshore Quaternary stratigraphy, tectonics, sedimentary evol ution, and environmental and engineering geology of this area.The following late Quaternary stratigraphic sequences were mapped. (1) Pleistoce ne alluvial silty sand and shallow marine clay; (2) coarse fluvial channel sand; (3 ) nearshore and bay clayey sediments. The incision of fluvial channels occurred in two stages: duri ng the Late Pleistocene and at the beginning of the Holocene. The Pleistocene fluvial channe ls have been filled by coarse sand overlain by more than 10 m of late Pleistocene clay and 20-30 m o f Holocene clay.The coastal area is dissected by two major fault systems: the first group strike s ENE-WSW and controls the evolution of the adjacent Quaternary basin, while the second one tr ends NNE-SSW. These fault systems must be taken into account in any coastal engineering consid erations. In addition, both granitic and metamorphic basements were recognized.

  3. Clay mineralogy of innershelf sediments off Cochin, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, N.V.N.D.; Dora, Y.L.

    Kaolinite, montmorillonite and illite are the clay minerals occurring in decreasing order of abundance in the Holocene sediments of inner shelf and adjacent coastal environments of Cochin Region. Southern part of Vembanad Lake, estuarine part...

  4. Mineralogy of polymetallic nodules and associated sediments from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.

    Todorokite is the dominant mineral phase in the nodules of the northern Central Indian Ocean Basin. These nodules are characterised by a rough surface texture, are relatively rich in Mn, Cu and Ni, and are associated with radiolarian sediments rich...

  5. Geochemical and Mineralogical Characteristics of Pleistocene Lignites and Associated Sediments of Marathousa Coal Field,Central Peloponnese,Greece

    Institute of Scientific and Technical Information of China (English)

    A.E.KELEPERTSIS; E.KONTIS

    1997-01-01

    The mineralogy and geochemistry data are presented for thirty-seven shales,four concretions,two carbonate sediments and seven lignites from the Marathousa coal field of the Megalopolis Basin in Greece.The argillaceous rocks consist of chlorite,illite,kaolinte,albite,quartz.opal-A,calcite and dolomite;the concretions of aragonite,gypsum and pyrite;and the carbonate rocks of calcite,quartz and illite.The mineral matter in the lignites consists of gypsum,quartz,albite,chlorite,illite,opal-A,dolomite,pyrite,and rarely calcite and kaolinite Athree-factor model explains the total variaition of major and trace elements in the argillaceous sediments.The first factor is an aluminosilicate factor and involves the following elements:Al,Si,Mg,Na,K,Ti,Mn,Nb,Y,Rb,Zn,Cu,Ni,Cr,Nband V,associated with chlorite,albite and illite.The second factor involves the elements Ca,Sr,Ba,Znand Sc and is related to carbonate lithology and mainly the carbonate concretions with gypsum.The third factor involves Fe and Ce with a weak association with Mn.The diagenesis of the Marathousa sediments and lignites was not very advanced as indicated by (a) the total thickness of the sequence (500m),(b) the presence of biogenic silica(opal-A) and (c) the age of the deposit(Pleistocene).FOr these reasons the rpresence of chlorite,illite and kaolinite in the sediments and lignite is due not to diagenetic reactions but to weathering of the flysch and metamorphic rocks at the edges of the Megalopolis Basin and transport of the weathering products(illite,chlorite,kaolinite)into the basin of deposition.The diagenetic minerals of the Marathousa sequence include pyrite,gypsum,dolomite and aragonite.

  6. Palynology and clay mineralogy of the Deccan volcanic associated sediments of Saurashtra, Gujarat: Age and paleoenvironments

    Indian Academy of Sciences (India)

    Bandana Samant; D M Mohabey; P Srivastava; Deepali Thakre

    2014-02-01

    The intertrappean sediments associated with Deccan Continental Flood Basalt (DCFB) sequence at Ninama in Saurashtra, Gujarat yielded palynoassemblage comprising at least 12 genera and 14 species including Paleocene taxa such as Intrareticulites brevis, Neocouperipollis spp., Striacolporites striatus, Retitricolpites crassimarginatus and Rhombipollis sp. The lava flows of Saurashtra represent the northwestern most DCFB sequence in India. It is considered that the Saurashtra lava flows represent the earliest volcanic activity in the Late Cretaceous of the Reunion Mantle Plume on the northward migrating Indian Plate. The present finding of the Paleocene palynoflora from Ninama sediments indicate Paleocene age for the associated lava flows occurring above the intertrappean bed which suggests that the Saurashtra plateau witnessed eruption of Deccan lava flows even during Paleocene. The clay mineral investigation of the Ninama sediments which are carbonate dominated shows dominance of low charge smectite (LCS) along with the presence of mica and vermiculite. Based on the clay mineral assemblage it is interpreted that arid climatic conditions prevailed during the sedimentation. The smectite dominance recorded within these sediments is in agreement with global record of smectite peak close to the Maastrichtian-Paleocene transition and climatic aridity.

  7. Strong magnetic levels in Lake Chapala sediments (western Mexico) : their mineralogy and stratigraphic significance

    OpenAIRE

    Michaud, François; Ramirez Sanchez, H.U.; Parron, C.; Zarate del Valle, P.F.; Fernex, F.; Barci Funel, G.

    2006-01-01

    Lake Chapala, located 120 km northeast of Colima Volcano, lies at the north and northeast of the Citala rift in the Trans-Mexican Volcanic Belt. It belongs to the watershed of the Lerma River, which originates from the Mexico City area, 450 km to the east. Sediment cores, 0.5-2 m long, were collected from the lake. Magnetic susceptibility of the lake sediments generally ranges from 400 to 800 x 10(-9) m(3) kg(-1); but in some layers it exceeds 1000 or 1500 x 10(-9) m(3) kg(-1). The magnetic s...

  8. Mineralogy of smectites in the surface sediments from the East Pacific and its significance

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    XRD, TEM, SEM and EDS are employed to analyze smectites in the clay fraction of the surface sediments from the East Pacific. It is shown from the XRD results that the clay fraction consists of about 20% smectites. Three types of smectites are identified, Fe-rich (TypeⅠ), Fe, Mg-rich (Type Ⅱ) and Na,Ca smectite (Type Ⅲ), and most of them are not well-crystallized. TypeⅠ is widely distributed in sediments, showing honeycomblike in the SEM, and aggregated or dispersive hairlike, or cloudy assemblage with a bit curl near its edge in the TEM. This type is considered to be typomorphic type of authigenic smectite in the East Pacific. TypeⅡ is similar to TypeⅠ in micromorphology in the TEM, showing a transition micronite, while Type Ⅲ is tabletlike in the TEM with an unclear edge. TypeⅠ may be altered from volcanics and some of them even precipitated from the low subthermal water. TypeⅡ could also be form- ed in the ocean floor, while Type Ⅲ comes from dry and distant continental area. This study suggests that the characteristic of chemical composition and morphology of smectite may give a clue to understand sediment source, origin of minerals and sedimentation in the deep sea.

  9. Mineralogy of smectites in the surface sediments from the East Pacific and its significance

    Institute of Scientific and Technical Information of China (English)

    ZHANGHaiping; SHIXuefa; CHENJin; XUEYongfang; HEJinfa; ZHUDesheng; XINChunying; WEIJianwei

    2003-01-01

    XRD, TEM, SEM and EDS are employed to analyze smectites in the clay fraction of the surface sediments from the East Pacific. It is shown from the XRD results that the clay fraction consists of about 20% smectites.Three types of smectites are identified, Fe-rich (Type Ⅰ), Fe,Mg-rich (Type Ⅱ) and Na,Ca smectite (Type Ⅲ), and most of them are not well-crystallized. Type Ⅰ is widely distributed in sediments, showing honeycomblike in the SEM, and aggregated or dispersive hairlike, or cloudy assemblage with a bit curl near its edge in the TEM. This type is considered to be typomorphic type of authigenic smectite in the East Pacific. Type Ⅱ is similar to Type Ⅰ in micromorphology in the TEM, showing a transition micronite, while Type Ⅲ is tabletlike in the TEM with an unclear edge. Type Ⅰ may be altered from voleanics and some of them even precipitated from the low subthermal water. Type Ⅱ could also be formed in the ocean floor, while Type Ⅲ comes from dry and distant continental area. This study suggests that the characteristic of chemical composition and morphology of smectite may give a clue to understand sediment source, origin of minerals and sedimentation in the deep sea.

  10. Land-sea duel in the late Quaternary at the mouth of a small river with high sediment yield

    Science.gov (United States)

    Yang, Rick J.; Liu, James T.; Fan, Daidu; Burr, George S.; Lin, Hui-Ling; Chen, Ting-Ting

    2017-08-01

    The transition between sedimentary environments is compressed along land-sea boundaries in space and time. At river mouths on high standing islands, sedimentary records with high temporal resolutions formed as a result of large sediment loads and pervasive post-glacial sea level rise. Here we report on sediment core records covering the late Quaternary from the mouth of a small mountainous river in Taiwan. Results show that the study site was initially terrestrial under fluvial control. Beginning at about 10,000 yr BP (before present) the site became inundated by the rising sea and the environmental facies transitioned from a floodplain/incised river valley to a succession of marine environments, from shoreface to offshore. As the rising sea level came to a pause at 6000 yr BP, fluvial processes became dominant and sediments began to aggrade at the river mouth. After 4500 yr BP, the accumulated sediment began to prograde seaward, taking on the form of a river delta, and subtidal sand ridges appeared in the nearshore. This also introduces the deltaic development, which was limited by topography of the receiving basin. The chronology expresses the duel between sea level and fluvial processes that determined the depositional environments along the land-sea boundary at the study site.

  11. Multiple ash layers in late Quaternary sediments from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas-Pereira, M.B.L.; Nath, B.N.; Iyer, S.D.; Borole, D.V.; Parthiban, G.; Jijin, R.; Khedekar, V.D.

    and dispersed shards. Rhyolitic glass shards of bubble wall, platy, angular and blocky types were retrieved from various stratigraphic horizons in the cores. The abundance of glass shards, composition of bulk sediments, and 230Thexcess ages of the host sediments...

  12. Geochemical and Mineralogical Investigation of Uranium in Multi–element Contaminated, Organic–rich Subsurface Sediment

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla; Gartman, Brandy N.; Kukkadapu, Ravi K.; Arey, Bruce W.; Williams, Kenneth H.; Mouser, Paula J.; Heald, Steve M.; Bargar, John R.; Janot, Noemie; Yabusaki, Steven B.; Long, Philip E.

    2014-03-02

    Alluvial sediments characterized by an abundance of refractory or lignitic organic carbon compounds and reduced Fe and S bearing mineral phases have been identified through drilling activities at the U.S. Department of Energy’s (DOE) Integrated Field Research Challenge (IFRC) site at Rifle, CO. Regions of the subsurface from which such sediments are derived are referred to as Naturally Reduced Zones (NRZ). We conducted a study with NRZ sediments with the objective to: i.) Characterize solid phase contamination of U and other co-contaminants; ii.) Document the occurrence of potential U host minerals; iii.) Determine U valence state and micron scale spatial association with co-contaminants. Macroscopic (wet chemical batch extractions and a column experiment), microscopic (SEM-EDS), and spectroscopic (Mössbauer, µ-XRF and XANES) techniques were employed. Results showed that sediments’ solid phase had significant concentrations of U, S, As, Zn, V, Cr, Cu and Se, and a remarkable assortment of potential U hosts (sorbents and/or electron donors), such as Fe oxides (hematite, magnetite, Al-substituted goethite), siderite, reduced Fe(II) bearing clays, sulfides of different types, Zn sulfide framboids and multi – element sulfides. Multi-contaminants, micron size (ca. 5 to 30 µm) areas of mainly U(IV) and some U(VI), and/or other electron scavengers or donors such as Se, As, Cr, and V were discovered in the sediments, suggesting complex micron-scale system responses to transient redox conditions, and different extent and rates of competing U redox reactions than those of single contaminant systems. Collectively, the results improve our understanding and ability to predict U and NRZ’s complex behavior and will delineate future research directions to further study both the natural attenuation and persistence of contaminant plumes and their contribution to groundwater contamination.

  13. Signatures and significance of aeolian, fluvial, bacterial and diagenetic magnetic mineral fractions in Late Quaternary marine sediments off Gambia, NW Africa

    NARCIS (Netherlands)

    Just, A.; Dekkers, M.J.; Dobeneck, T. von; Hoesel, A. van; Bickert, T.

    2012-01-01

    Two gravity cores retrieved off NW Africa at the border of arid and subtropical environments (GeoB 13602–1 and GeoB 13601–4) were analyzed to extract records of Late Quaternary climate change and sediment export. We apply end-member (EM) unmixing to 350 acquisition curves of isothermal remanent magn

  14. Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

    Directory of Open Access Journals (Sweden)

    D. McIlroy

    2004-09-01

    Full Text Available By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

  15. Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

    Directory of Open Access Journals (Sweden)

    S. J. Needham

    2004-01-01

    Full Text Available By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

  16. Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer.

    Science.gov (United States)

    Zhang, Shouliang; Kent, Douglas B; Elbert, David C; Shi, Zhi; Davis, James A; Veblen, David R

    2011-06-01

    Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy (TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle mechanical grinding method and focused ion beam (FIB) milling. The former method can make abundant electron-transparent coating assemblages for comprehensive and quantitative X-ray analysis and the latter technique protects the coating texture from being destroyed. Characterization of the samples from both a pristine area and an area heavily impacted by wastewater discharge shows similar coating textures and chemical compositions. Major constituents of the coating include Al-substituted goethite and illite/chlorite clays. Goethite is aggregated into well-crystallized domains through oriented attachment resulting in increased porosity. Illite/chlorite clays with various chemical compositions were observed to be mixed with goethite aggregates and aligned sub-parallel to the associated quartz surface. The uniform spatial distribution of wastewater-derived phosphorus throughout the coating from the wastewater-contaminated site suggests that all of the coating constituents, including those adjacent to the quartz surface, are accessible to groundwater solutes. Both TEM characterization and chemical extraction results indicate there is a significantly greater amount of amorphous iron oxide in samples from wastewater discharge area compared to those from the pristine region, which might reflect the impact of redox cycling of iron under the wastewater-discharge area. Coating compositions are consistent with the moderate metal and oxy-metalloid adsorption capacities, low but significant cation exchange capacities, and control of iron(III) solubility by goethite observed in reactive transport

  17. Changes in Magnetic Mineralogy Through a Depth Sequence of Hydrocarbon Contaminated Sediments

    Science.gov (United States)

    Ameen, N. N.; Klüglein, N.; Appel, E.; Petrovsky, E.; Kappler, A.

    2013-12-01

    Sediments, soils and groundwater can act as a natural storage for many types of pollution. This study aims to investigate ferro(i)magnetic phase formation and transformation in the presence of organic contaminants (hydrocarbons) and its relation to bacterial activity, in particular in the zone of fluctuating water levels. The work extends previous studies conducted at the same site. The study area is a former military air base at Hradčany, Czech Republic (50°37'22.71"N, 14°45'2.24"E). Due to leaks in petroleum storage tanks and jet fuelling stations over years of active use the site was heavily contaminated with petroleum hydrocarbons, until the base was closed in 1991. This site is one of the most important sources of high quality groundwater in the Czech Republic. During remediation processes the groundwater level in the sediments fluctuated, driving the hydrocarbon contaminants to lower depth levels along with the groundwater and leading to magnetite formation (Rijal et al., Environ.Pollut., 158, 1756-1762, 2010). In our study we drilled triplicate cores at three locations which were studied earlier. Magnetic susceptibility (MS) profiles combined with other magnetic properties were analyzed to obtain the ferro(i)magnetic concentration distributions along the depth sections. Additionally the sediment properties, hydrocarbon content and bacterial activity were studied. The triplicate cores were used to statistically discriminate outliers and to recognize significant magnetic signatures with depth. The results show that the highest concentration of ferrimagnetic phases (interpreted as newly formed magnetite) exists at the probable top of the groundwater fluctuation (GWF) zone. For example at one of the sites this zone is found between 1.4-1.9 m depth (groundwater table at ~2.3 m depth). High S-ratio and the correlation of ARM with MS values confirm the contribution of magnetite for the ferro(i)magnetic enhancement in the GWF zone. In the previous studies the MS

  18. Study of environmental pollution and mineralogical characterization of sediment rivers from Brazilian coal mining acid drainage

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis F.O., E-mail: felipeqma@hotmail.com [Environmental Science and Nanotechnology Department, Institute of Environmental Research and Human Development – IPADH, Capivari de Baixo, Santa Catarina (Brazil); Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Fdez- Ortiz de Vallejuelo, Silvia; Martinez-Arkarazo, Irantzu; Castro, Kepa [Department of Analytical Chemistry, University of the Basque Country (EHU/UPV), P.O. Box 644, 48080 Bilbao, Basque Country (Spain); Oliveira, Marcos L.S. [Environmental Science and Nanotechnology Department, Institute of Environmental Research and Human Development – IPADH, Capivari de Baixo, Santa Catarina (Brazil); Sampaio, Carlos H.; Brum, Irineu A.S. de [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Gonçalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre, RS (Brazil); Leão, Felipe B. de; Taffarel, Silvio R. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Madariaga, Juan M. [Department of Analytical Chemistry, University of the Basque Country (EHU/UPV), P.O. Box 644, 48080 Bilbao, Basque Country (Spain)

    2013-03-01

    Acid drainage from coal mines and metal mining is a major source of underground and surface water contamination in the world. The coal mining acid drainage (CMAD) from mine contains large amount of solids in suspension and a high content of sulphate and dissolved metals (Al, Mn, Zn, Cu, Pb, Fe, etc.) that finally are deposited in the rivers. Since this problem can persist for centuries after mine abandonment, it is necessary to apply multidisciplinary methods to determine the potential risk in a determinate area. These multidisciplinary methods must include molecular and elemental analysis and finally all information must be studied statistically. This methodology was used in the case of coal mining acid drainage from the Tubarao River (Santa Catarina, Brazil). During molecular analysis, Raman Spectroscopy, electron bean, and X-ray diffraction (XRD) have been proven very useful for the study of minerals present in sediment rivers near this CMAD. The obtained spectra allow the precise identification of the minerals as jarosite, quartz, clays, etc. The elemental analysis (Al, As, Fe, K, Na, Ba, Mg, Mn, Ti, V, Zn, Ag, Co, Li, Mo, Ni, Se, Sn, W, B, Cr, Cu, Pb and Sr) was realised by inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis (Principal Component Analysis) of these dates of concentration reveals the existence of different groups of samples with specific pollution profiles in different areas of the Tubarao River. Highlights: ► Increasing coal drainage sediments geochemical information will increase human health information in this area. ► Brazilian coal mining information will increase recuperation planning information. ► The nanominerals showed strong sorption ability to aqueous hazardous elements.

  19. Chronology and processes of late Quaternary hillslope sedimentation in the eastern South Island, New Zealand

    DEFF Research Database (Denmark)

    Borella, Josh; Quigley, Mark; Sohbati, Reza

    2016-01-01

    ) for sediment aggradation (i.e. colluvial wedges) and upbuilding soil formation. Sediment accumulation rates increased considerably (>10 factor increase) following human arrival and associated anthropogenic burning of hillslope vegetation. Our study presents new numerical ages to place the evolution of loess...

  20. Clay mineralogy, grain size distribution and their correlations with trace metals in the salt marsh sediments of the Skallingen barrier spit, Danish Wadden Sea

    DEFF Research Database (Denmark)

    He, Changling; Bartholdy, Jesper; Christiansen, Christian

    2012-01-01

    metals. The clay assembly of the sediment consists of illite, kaolinite and much less chlorite and smectite. The major clay minerals of illite, kaolinite as well as chlorite correlate very poorly with all the trace metals investigated, due probably to the weak competing strength of these clays compared...... with the other adsorbents and to low availability of the mobile trace metals in the system. Correlation between trace metals and clay minerals may therefore be used as an indicator in environmental assessment. Fine grain fractions of the sediment increased markedly after salt marsh invasion in about 1931......To understand the behavior of trace metals in the salt marsh at Skallingen, Danish Wadden Sea, we investigated a profile from surface to 25 cm depth of the salt marsh sediment, focusing primarily on clay mineralogy and grain size distribution of the sediments and their relationship with trace...

  1. Provenance of late Oligocene to quaternary sediments of the Ecuadorian Amazonian foreland basin as inferred from major and trace element geochemistry and Nd-Sr isotopic composition

    Science.gov (United States)

    Roddaz, Martin; Christophoul, Frédéric; Burgos Zambrano, José David; Soula, Jean-Claude; Baby, Patrice

    2012-08-01

    Oligocene to Quaternary deposits from the Oriente Amazonian foreland basin (Ecuador and Peru) were analyzed for major and trace element geochemistry (46 and 32 samples respectively) and Nd-Sr isotopic systematics (n = 10). Chemical Index of Alteration values lower than those of other Amazonian foreland basin sediments and scattering along the AK join in the A-CN-K diagram indicate that the Oriente foreland basin has been continuously fed by poorly to moderately weathered sediments having an overall Andesitic composition since the Oligocene. Chemical ratios such as Cr/Th and Th/Sc as well as Eu anomaly and Nd-Sr isotopic compositions indicate that most of the analyzed sediments contained a greater proportion of volcanic arc rock material than the other Amazonian foreland basin sediments. When compared with the older sediments The Quaternary sediments are characterized by a greater contribution of the volcanic arc source. The composition of the sediments deposited in the Ecuadorian Amazonian foreland basin is mainly controlled by geodynamic processes. We suspect the Late Pliocene-Pleistocene subduction of the Carnegie ridge to be responsible for the back arc volcanism feeding the Amazonian foreland with more basic materials. Input of young Ecuadorian volcanic rocks may explain the difference in Sr and Nd isotopic ratios of suspended sediments between the Solimoes and the Madeira rivers.

  2. Geomorphological map and preliminary analysis of Quaternary sediments in the Planica-Tamar valley (Julian Alps, NW Slovenia)

    Science.gov (United States)

    Novak, Andrej; Šmuc, Andrej

    2016-04-01

    moderately sorted clast or sandy matrix-supported angular gravels occur. In cross-sections of alluvial fans distinct palaeosoil horizons are present indicating longer inactivity of that part of the fan. The geomorphological map forms a base for further research and thorough analysis of Quaternary deposits in order to reconstruct the Holocene dynamic of triggering and sedimentation of different types of slope deposits and relate them to base rock geology, tectonic and local/regional climate events. Key words: geomorphological mapping, Holocene slope deposits, alluvial fans, debris fans, Alpine geomorphology.

  3. Study of environmental pollution and mineralogical characterization of sediment rivers from Brazilian coal mining acid drainage.

    Science.gov (United States)

    Silva, Luis F O; Fdez-Ortiz de Vallejuelo, Silvia; Martinez-Arkarazo, Irantzu; Castro, Kepa; Oliveira, Marcos L S; Sampaio, Carlos H; de Brum, Irineu A S; de Leão, Felipe B; Taffarel, Silvio R; Madariaga, Juan M

    2013-03-01

    Acid drainage from coal mines and metal mining is a major source of underground and surface water contamination in the world. The coal mining acid drainage (CMAD) from mine contains large amount of solids in suspension and a high content of sulphate and dissolved metals (Al, Mn, Zn, Cu, Pb, Fe, etc.) that finally are deposited in the rivers. Since this problem can persist for centuries after mine abandonment, it is necessary to apply multidisciplinary methods to determine the potential risk in a determinate area. These multidisciplinary methods must include molecular and elemental analysis and finally all information must be studied statistically. This methodology was used in the case of coal mining acid drainage from the Tubarao River (Santa Catarina, Brazil). During molecular analysis, Raman Spectroscopy, electron bean, and X-ray diffraction (XRD) have been proven very useful for the study of minerals present in sediment rivers near this CMAD. The obtained spectra allow the precise identification of the minerals as jarosite, quartz, clays, etc. The elemental analysis (Al, As, Fe, K, Na, Ba, Mg, Mn, Ti, V, Zn, Ag, Co, Li, Mo, Ni, Se, Sn, W, B, Cr, Cu, Pb and Sr) was realised by inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis (Principal Component Analysis) of these dates of concentration reveals the existence of different groups of samples with specific pollution profiles in different areas of the Tubarao River.

  4. Mineralogy and fluid content of sediments entering the Costa Rica subduction zone - Results from Site U1414, IODP Expedition 344

    Science.gov (United States)

    Charpentier, D.; Buatier, M.; Kutterolf, S.; Straub, S. M.; Nascimento, D.; Millan, C.

    2013-12-01

    Subduction zones are characterized by the largest thrust earthquakes, as quantified by both rupture area and seismic moment release. Offshore Costa Rica, the oceanic Cocos Plate subducts under the Caribbean plate forming the southern end of the Middle America trench. A high convergence rate and almost complete subduction of incoming sediments make the Costa Rica convergent margin an extremely dynamic environment. The Costa Rica Seismogenesis Project (CRISP) is designed to understand the processes that control nucleation and seismic rupture of large earthquakes at erosional subduction zones. Site U1414 of IODP Exp.344 was drilled to investigate the material from the incoming Cocos Plate. A key parameter of incoming plate is fluid content and release because it impacts deformation within the subduction complex. The deposition, compaction and diagenesis of sedimentary rocks control the distribution of fluids, fluid pressures and fluid flow patterns within subduction zones. We therefore decided to characterize sediment composition and quantify the different types of water at Site U1414. Mineralogical investigations were performed using optical and electronic microscope observations, X Ray Diffraction (on bulk and clay fractions), Cation Exchange Capacity measurements, carbon analyses (to determine carbonate contents), and sequenced extractions in NaOH (to quantify the biogenic opal content). Fluid characteristics were approached by thermal gravimetric analyses. The entire sedimentary sequence was recovered at Site U1414 and can be divided into three major sedimentary units. The first one is a hemipelagic silty clay to clay with a gradual increase of calcareous nannofossils. The dominant mineral is smectite associated in the clay fractions with kaolinite and zeolites. Small amounts of biogenic opal have been analyzed. Other minerals like quartz, feldspar and calcite are also present. The second unit is composed of nannofossil-rich calcareous ooze. The proportion of

  5. ESR dating of quartz extracted from quaternary and neogene sediments: method, potential and actual limits

    Science.gov (United States)

    Laurent, M.; Falguères, C.; Bahain, J. J.; Rousseau, L.; Van Vliet Lanoé, B.

    ESR dating of fluvial, fluvio-marine and beach sediment has been tested using the Al centre in quartz grains from a basin and fossil beaches located around the Manche Channel. Dating was performed in conjunction with sedimentological, stratigraphical and neotectonical studies. The technical basis of the method is presented in the light of the study made on recent and fossil sediment in order to establish a procedure for the determination of the palaeodose. The application on a Neogene Basin samples allows to push back the dating ESR limits. Results show that ESR dating of sediment can provide chronozons which are necessary to the uderstanding of the history of a basin where classical chronological markers do not exist.

  6. Isotopic and geochemical signatures of Late Quaternary sediments in the Fram Strait area

    Science.gov (United States)

    Maccali, J.; Hillaire-Marcel, C.; Carignan, J.; Reisberg, L. C.

    2010-12-01

    Arctic freshwater/sea-ice export through Fram Strait contributes to the Atlantic Meridional Overturning Circulation (AMOC) and acts as a trigger or feedback mechanism in the climate/ocean system. Here, geochemical and isotopic analyses of cores raised along a transect through the Strait are used to document changes in sediment sources and sea-ice transport since the LGM. Radiogenic isotope and elemental data in leachable fractions vs residues are used as proxies for water mass vs sediment source signatures, respectively. Unequivocal linkage between leachates and water-mass properties are illustrated by the anthropogenic-lead overprint in leachates from core-top sediments. Below this polluted layer, leachates and residues from late Holocene sediments carry distinct geochemical signatures E and W of the Strait. Eastward, below the North Atlantic Water (NAW) mass flowing northward, Th/Zr and Th/Pb concentration ratios ranging 0.040-0.041 and 0.85-0.90, respectively, label GIN seas and western Spitzbergen sediment-sources. Westward, below outflowing Arctic waters and sea-ice routes, these ratios range 0.032-0.035 and 0.72-0.75, respectively, and label NE Greenland and Arctic sediment sources. Pb-isotopes exhibit a similar pattern with sediment carrying a mixed Variscan-Pan-African signature below the NAW route, and a mixture of less radiogenic sources in sediments deposited below the outflowing Arctic waters and sea-ice route. Back in time, divergent trends in some radiogenic isotope values are recorded westward, below the outflowing Arctic waters and sea-ice route. Whereas isotopic properties of residues suggest sedimentary supplies originating from the Canadian Arctic and/or the NW Greenland margin, lead data from leachates bear an "Arctic Ocean" signature illustrating variable relative contributions from the Russian vs Canadian ice-margins and/or rivers. During deglacial times, a significant change in sedimentary supplies is recorded at ~ 14 ka along with some

  7. Paleo-environmental imprint on microbiology and biogeochemistry of coastal quaternary sediments

    Directory of Open Access Journals (Sweden)

    M. Beck

    2010-07-01

    Full Text Available To date, North Sea tidal flat sediments have been intensively studied down to a depth of 5 m below sea floor (mbsf. However, little is known about the biogeochemistry, microbial abundance, and activity of sulfate reducers as well of methanogens in deeper layers. For this study, we hypothesized that the imprint of the paleo-environment is reflected in current microbiogeochemical processes. Therefore, 20 m-long cores were retrieved from the tidal-flat area of Spiekeroog Island, NW Germany. Two drill sites were selected with a close distance of only 900 meters, but where sedimentation occurred under different environmental conditions: first, a paleo-channel filled with Holocene sediments and second, a mainly Pleistocene sedimentary succession. In general, the numbers of bacterial 16S rRNA genes are one to two orders of magnitude higher than those of Archaea. The abundances of key genes for sulfate reduction and methanogenesis (dsrA and mcrA correspond to the sulfate and methane profiles. A co-variance of these key genes at sulfate-methane interfaces and enhanced potential AOM rates suggest that anaerobic oxidation of methane may occur in these layers. Microbial and biogeochemical profiles are vertically stretched relative to 5 m-deep cores from shallower sediments in the same study area. Compared to the deep marine environment, the profiles are transitional between the shallow subsurface and the marine deep biosphere. Our interdisciplinary analysis shows that the microbial abundances and metabolic rates are elevated in the Holocene compared to Pleistocene sediments. However, this is mainly due to present environmental conditions such as pore water flow and organic matter availability. The paleo-environmental imprint is still visible but superimposed by these processes.

  8. Imprint of past and present environmental conditions on microbiology and biogeochemistry of coastal Quaternary sediments

    Directory of Open Access Journals (Sweden)

    M. Beck

    2011-01-01

    Full Text Available To date, North Sea tidal-flat sediments have been intensively studied down to a depth of 5 m below seafloor (mbsf. However, little is known about the biogeochemistry, microbial abundance, and activity of sulfate reducers as well as methanogens in deeper layers. In this study, two 20 m-long cores were retrieved from the tidal-flat area of Spiekeroog Island, NW Germany. The drill sites were selected with a close distance of 900 m allowing to compare two depositional settings: first, a paleo-channel filled with Holocene sediments and second, a mainly Pleistocene sedimentary succession. Analyzing these cores, we wanted to test to which degree the paleo-environmental imprint is superimposed by present processes.

    In general, the numbers of bacterial 16S rRNA genes are one to two orders of magnitude higher than those of Archaea. The abundances of key genes for sulfate reduction and methanogenesis (dsrA and mcrA correspond to the sulfate and methane profiles. A co-variance of these key genes at sulfate-methane interfaces and enhanced ex situ AOM rates suggest that anaerobic oxidation of methane may occur in these layers. Microbial and biogeochemical profiles are vertically stretched relative to 5 m-deep cores from shallower sediments in the same study area, but still appear compressed compared to deep sea sediments. Our interdisciplinary analysis shows that the microbial abundances and metabolic rates are elevated in the Holocene compared to Pleistocene sediments. However, this is mainly due to present environmental conditions such as pore water flow and organic matter availability. The paleo-environmental imprint is still visible but superimposed by these processes.

  9. Geochemistry of late Quaternary tephra-sediment sequence from north-eastern Basin of Mexico (Mexico): implications to tephrochronology, chemical weathering and provenance

    OpenAIRE

    Priyadarsi D. Roy; José Luis Arce; Rufino Lozano; M.P. Jonathan; Elena Centeno; Socorro Lozano

    2012-01-01

    A ca.30 m thick tephra-sediment sequence from the north-eastern Basin of Mexico (Pachuca subbasin, central Mexico) is investigated for stratigraphy and multi-element geochemistry to understand the tephrochronology, provenance and conditions of chemical weathering during Late Quaternary. Chemical compositions of tephra layers are compared with products from surrounding volcanic structures (Apan- Tezontepece, Acoculco, Huichapan, Sierra de las Cruces and Tláloc) in order to identify their sourc...

  10. Linking glacial melting to Late Quaternary sedimentation in climatically sensitive mountainous catchments of the Mount Chlemos compex, Kalavryta, southern Greece

    Science.gov (United States)

    Pope, Richard; Hughes, Philip

    2014-05-01

    local last glacial maximum and are coeval with the later part of the Tymphian stage in the Pindus range. Refs: Hughes, P.D., Woodward, J.C., Gibbard, P.L., Macklin, M.G., Gilmour, M.A. & Smith G.R. (2006) The glacial history of the Pindus Mountains, Greece. Journal of Geology 114, 413-434. Hughes, P.D., Woodward, J.C., van Calsteren, P.C. and Thomas, L.E. (2011) The Glacial History of The Dinaric Alps, Montenegro. Quaternary Science Reviews 30, 3393-3412. Woodward, J.C., Hamlin, R.H.B., Macklin, M.G., Hughes, P.D. & Lewin, J. (2008) Pleistocene catchment dynamics in the Mediterranean: glaciation, fluvial geomorphology and the slackwater sediment record. Geomorphology 101, 44-67.

  11. Nannofossils in upper quaternary bottom sediments of back-arc basins in the southwestern Pacific

    Science.gov (United States)

    Dmitrenko, O. B.

    2015-05-01

    The analysis of calcareous nannoplankton assemblages in bottom sediments sampled during Cruise 21 of the R/V Akademik Mstislav Keldysh in three areas located in back-arc basins of the southwestern Pacific (western Woodlark in the Solomon Sea, Manus in the Bismarck Sea, Central Lau) reveal that they belong to the Emiliania huxleyi Acme Zone, the most detailed one in the Gartner's scale of 1977. The content of coccoliths and their taxonomic composition indicate warm subtropical-tropical conditions. Long cores demonstrate a decrease in species diversity reflecting the transition from the cold late Pleistocene to the Holocene. The changes in species diversity and presence/absence of thermophilic representatives indicate transformation of depositional environments with unstable conditions in the water column and bottom layer, seismic activity, and widely developed processes of sediment redistribution and reworking.

  12. Subdivision of Pantanal Quaternary Wetlands: Modis Ndvi Timeseries in the Indirect Detection of Sediments Granulometry

    Science.gov (United States)

    Penatti, N. C.; de Almeida, T. I. R.

    2012-07-01

    The Pantanal is the world's largest wetland presenting a variety of ecological sub-regions. The region is characterized by seasonal floods followed by long droughts. At this period, some areas rapidly dry, while others remain soaked. The study hypothesis was based on the statement that this phenomenon cannot be totally explained by small relief variations but by the sediment granulometry: the pelitic sediments allow the soil to retain moisture longer, implying that the vegetation has greater possibilities of continuing photosynthetically active even during the drought. It was developed based on the spectral behaviour of MODIS products, validated by previous fieldwork. Using MODIS, we studied a large scale patterns in spatial and seasonal dynamics of the vegetation in different regions of Pantanal. So, two indirect parameters of the local physical environment - sediment granulometry and water availability - potentially can be estimated. We calculated the NDVI from MOD09GQ for rainy and dry seasons, generating triplets (NDVI/NIR and Red bands) that allowed to identify vegetation changes in those periods. The 16-days composites of NDVI (MOD13Q1) were used to generate a 5-year time-series for pixels associated with 161 locals sampled for granulometric analyses. The samples were taken in 10 different areas from the 20 geological and environmentally homologous areas delimited in this research. The clear tendency in the time-series confirms the working hypothesis, indicating that there is a high relationship between drought-related changes in vegetation extracted from NDVI and sediment texture, parameter that plays an important role in soil moisture, influencing the vegetation response to droughts.

  13. Seismically-induced structures in the Quaternary sediments of the NE Fennoscandian Shield: Features and age

    OpenAIRE

    Nikolaeva S. B.

    2016-01-01

    Results of studying secondary seismogenic deformations of the vibrational type (termed "seismites") in loose sediments of the north-eastern Baltic Shield (the Kola region) have been provided. The features, types, formation patterns and age of seismites have been considered. On the basis of previous results the major periods of the region activation in the Holocene have been defined. Criteria of identifying similar structures with widely spread glaciodislocations have been suggested. Results o...

  14. Recent and Late Quaternary sedimentation processes in the area of the SE Mediterranean Sea

    Science.gov (United States)

    Hamann, Y.; Ehrmann, W.; Schmiedl, G.; Dulski, P.; Kuhnt, T.

    2007-12-01

    The present distribution of clay minerals in the southeastern Levantine Sea reveals a complex pattern of different source areas and dispersions of the main clay minerals smectite, illite, kaolinite, chlorite, and palygorskite. Smectite dominates the suspension load of the Nile River and rivers of the Near East. Sources of illite are dust- bearing winds blowing from the Saharan desert and the northern mainland of the Levantine Sea. Kaolinite is prevalent in the sediment yield of rivers which drain the Sinai, in sediments of wadis which discharge into the Nile River, and in dust loads of African storms. Palygorskite and chlorite are mainly derived from several dust bearing wind systems of the North and Central African continent, whereas chlorite is also provided by dust-bearing winds of the northeastern Mediterranean mainland. The clay mineral distributions and XRF element data of a sediment core from the southeastern Levantine Sea, spanning the last 27,000 years, show that the sediments are mainly affected by the discharge of the Nile River. The provenance of clay minerals provides a sensitive recorder of changes in the Nile River discharge and therefore in the climate conditions in the catchment of its tributaries. The glacial section of the core is characterized by low smectite concentrations, high K/Al ratios and low linear sedimentation rates when compared to the Holocene suggesting a low influence by the Nile outflow. Subsequently, during the early and middle Holocene, when the North African continent was influenced by more humid conditions during the African Humid Period, our record shows high proportions of smectite and low K/Al ratios which likely reflect higher discharge rates of the River Nile. In contrast to the sharp beginning and end of the African Humid Period as recorded in West African records at 15 and 5.5 kyr BP, our record in the southeastern Levantine Sea shows more transitional patterns and trend towards slightly lower Nile discharge rates at

  15. Using SOTEM Method to Detect BIF Bodies Buried Under Very Thick and Conductive Quaternary Sediments, Huoqiu Deposit, China

    Science.gov (United States)

    Chen, Weiying; Xue, Guoqiang; Khan, Muhammad Younis; Li, Hai

    2016-09-01

    Huoqiu iron deposit is a typical Precambrian banded iron-formation (BIF) field which is located in the North China Craton (NCC). To detect the deep ore bodies around Dawangzhuang Village in Yingshang County, north of the Huoqiu deposit field, electromagnetic methods were tested. As the ore bodies are buried under very thick conductive Quaternary sediments, the use of EM methods is a great challenge. Short-offset transient electromagnetic method (SOTEM) was applied in the area as we wanted to test due to its detection depth and resolution. A 2D model was first built according to the geology information and magnetic measurement results. Then, 2D forward and 1D inversion were carried out using FDTD and Occam's algorithm, respectively. The synthetic modeling results helped us with the survey design and interpretation. Two 1400-m-long survey lines with offset of 500 and 1000 m were laid perpendicular to the BIF's strike, and the transmitting parameters were selected by a test measurement at the vicinity of a local village. Finally, the structure of survey area and BIF bodies were determined based on the 1D inversion results of real data, and showed a consistency with the subsequent drill results. Our application of SOTEM in detecting hidden BIF buried under very thick conductive layer has shown that the method is capable of penetrating great depth more than 1000 m even in a very conductive environment and will be an effective tool for deep resources investigation.

  16. The age measures and its layer sequence tratigraphy of Late Quaternary sediment in Lushan Dajiaochang of China

    Institute of Scientific and Technical Information of China (English)

    Hu Dongsheng; Hu Rong; Li Xiaoyu; Hu Wenxuan; Wang Xulong; Tian Xingong; Liu Weiguo; Zhang Guowei

    2013-01-01

    Through the scientific investigation on Lushan for a long time,detailed studies have been carried out on the geologic stratum section of Late Quaternary in Dajiaochang. The series age data of complete stratigraphic section and full time formation since 400 kaBP were based on the results of the analyses using the dating methods with various instruments such as the ancient geomagnetism,electronics spin resonance (ESR),36Cl and lumines-cence dating,etc. Corresponding to these data,it identified the paleomagnetic polarity events including Biwa-Ⅲevent (320 kaBP),Biwa-Ⅱevent (260 kaBP),Biwa-Ⅰevent (180 kaBP,scarcity due to the disturbance of the iron dish),Blake event (100 kaBP) and Laschamp event (20 kaBP,didn’t grow due to the activities of the surface), etc. Combined with the sequence stratigraphy,layer type characteristics and its sediment environment,the strati-graphic can be divided into 4 stages of development respectively:StageⅠis the climate period of glacial epoch (200~400 kaBP);stageⅡis the climate period of interglacial epoch (100~200 kaBP);stageⅢis the climate peri-od of periglacial epoch (10~100 kaBP);stageⅣis the climate period of postglacial epoch (0~10 kaBP).

  17. Using SOTEM Method to Detect BIF Bodies Buried Under Very Thick and Conductive Quaternary Sediments, Huoqiu Deposit, China

    Science.gov (United States)

    Chen, Weiying; Xue, Guoqiang; Khan, Muhammad Younis; Li, Hai

    2017-03-01

    Huoqiu iron deposit is a typical Precambrian banded iron-formation (BIF) field which is located in the North China Craton (NCC). To detect the deep ore bodies around Dawangzhuang Village in Yingshang County, north of the Huoqiu deposit field, electromagnetic methods were tested. As the ore bodies are buried under very thick conductive Quaternary sediments, the use of EM methods is a great challenge. Short-offset transient electromagnetic method (SOTEM) was applied in the area as we wanted to test due to its detection depth and resolution. A 2D model was first built according to the geology information and magnetic measurement results. Then, 2D forward and 1D inversion were carried out using FDTD and Occam's algorithm, respectively. The synthetic modeling results helped us with the survey design and interpretation. Two 1400-m-long survey lines with offset of 500 and 1000 m were laid perpendicular to the BIF's strike, and the transmitting parameters were selected by a test measurement at the vicinity of a local village. Finally, the structure of survey area and BIF bodies were determined based on the 1D inversion results of real data, and showed a consistency with the subsequent drill results. Our application of SOTEM in detecting hidden BIF buried under very thick conductive layer has shown that the method is capable of penetrating great depth more than 1000 m even in a very conductive environment and will be an effective tool for deep resources investigation.

  18. Geochemical characteristics of late Quaternary sediments from the southern Aegean Sea (Eastern Mediterranean)

    OpenAIRE

    A. SIOULAS; CH. ANAGNOSTOU; A.P. KARAGEORGIS; C.D. GARBE-SCHONBERG

    2012-01-01

    Ten cores from the southern Aegean Sea have been logged for their lithological composition and seventy-three sub-samples were analysed for the determination of major and trace elements concentrations. Four lithological units were identified, namely, mud, volcanic, turbidite and sapropel. On the basis of the “Z-2” Minoan ash layer radiocarbon age sedimentation rates for the southern Aegean Sea were estimated at 3.26 to 4.15 cm kyr -1. Simple correlation analysis revealed three groups of elemen...

  19. Seismically-induced structures in the Quaternary sediments of the NE Fennoscandian Shield: Features and age

    Directory of Open Access Journals (Sweden)

    Nikolaeva S. B.

    2016-03-01

    Full Text Available Results of studying secondary seismogenic deformations of the vibrational type (termed "seismites" in loose sediments of the north-eastern Baltic Shield (the Kola region have been provided. The features, types, formation patterns and age of seismites have been considered. On the basis of previous results the major periods of the region activation in the Holocene have been defined. Criteria of identifying similar structures with widely spread glaciodislocations have been suggested. Results of studying the sections with seismites in certain areas of the region have been provided

  20. Geochemical characteristics of late Quaternary sediments from the southern Aegean Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    A. SIOULAS

    2012-12-01

    Full Text Available Ten cores from the southern Aegean Sea have been logged for their lithological composition and seventy-three sub-samples were analysed for the determination of major and trace elements concentrations. Four lithological units were identified, namely, mud, volcanic, turbidite and sapropel. On the basis of the “Z-2” Minoan ash layer radiocarbon age sedimentation rates for the southern Aegean Sea were estimated at 3.26 to 4.15 cm kyr -1. Simple correlation analysis revealed three groups of elements associated with: (1 biogenic carbonates; (2 terrigenous alumino-silicates and (3 sapropelic layers. R-mode factor analysis applied on the carbonate-free corrected data-set defined four significant factors: (1 the “detrital alumino-silicate factor” represented by Si, Al, Na, K, Rb, Zr, Pb and inversely related to Ca, Mg, and Sr; (2 a “hydrothermal factor” loaded with Cr, Ni, Co, Cu, Fe; (3 the “volcanic ash factor” with high loadings for Ti, Al, Fe, Na and (4 a “sapropel factor” represented by Ba, Mo, and Zn. High factor scores for the “hydrothermal factor” were observed in sediment samples proximal to Nisyros Isl., suggesting a potential hydrothermal influence. Red-brown oxides and crusts dredged from this area support further this possibility. The use of factor analysis enabled for a better understanding of the chemical elements associations that remained obscured by correlation analysis.

  1. Geochemical characteristics of late Quaternary sediments from the southern Aegean Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    A. SIOULAS

    2000-12-01

    Full Text Available Ten cores from the southern Aegean Sea have been logged for their lithological composition and seventy-three sub-samples were analysed for the determination of major and trace elements concentrations. Four lithological units were identified, namely, mud, volcanic, turbidite and sapropel. On the basis of the “Z-2” Minoan ash layer radiocarbon age sedimentation rates for the southern Aegean Sea were estimated at 3.26 to 4.15 cm kyr -1. Simple correlation analysis revealed three groups of elements associated with: (1 biogenic carbonates; (2 terrigenous alumino-silicates and (3 sapropelic layers. R-mode factor analysis applied on the carbonate-free corrected data-set defined four significant factors: (1 the “detrital alumino-silicate factor” represented by Si, Al, Na, K, Rb, Zr, Pb and inversely related to Ca, Mg, and Sr; (2 a “hydrothermal factor” loaded with Cr, Ni, Co, Cu, Fe; (3 the “volcanic ash factor” with high loadings for Ti, Al, Fe, Na and (4 a “sapropel factor” represented by Ba, Mo, and Zn. High factor scores for the “hydrothermal factor” were observed in sediment samples proximal to Nisyros Isl., suggesting a potential hydrothermal influence. Red-brown oxides and crusts dredged from this area support further this possibility. The use of factor analysis enabled for a better understanding of the chemical elements associations that remained obscured by correlation analysis.

  2. Fine grain IRSL and GLSL dating of late Quaternary sediments from North China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A possible approach to assess the fine grain OSL dating isdiscussed through comparison of equivalent dose (DE) values and ages obtained by IRSL and GLSL of fine grains for 31 sediment samples from North China. The IRSL and GLSL were measured with the same aliquots for each sample, i.e. shine-down was by 100 s of IRSL (880 nm) followed by 100 s of GLSL (514 nm) on the same discs. The DE values and ages found by IRSL are in good agreement with those by GLSL within 1-2σfor 80% samples, especially for aeolian loess samples. Considering that IRSL from feldspar differs obviously from GLSL dominated from quartz in dose response, thermal stability and optical bleaching characteristic, the agreement between the DE values may be taken as evidence that the two clocks of IRSL and GLSL had been well reset during deposition. The consistent ages of IRSL and GLSL, in turn, may be referred to an indicator to evaluate the fine grain OSL dating of sediments.

  3. Quaternary terrestrial climatic response to orbital forcing printed in Lake Baikal sediment

    Institute of Scientific and Technical Information of China (English)

    OCHIAI Shinya; KASHIWAYA Kenji

    2011-01-01

    The long sediment core BDP98 obtained from Lake Baikal was analyzed in order to discuss the periodicity of glacial cycles in the terrestrial climatic record of the past 2.6 Ma. Spectral analysis shows that the Baikal grain size record has been dominated by orbit-related cycles with periods of about 100 ka, 41 ka, and 23 ka, similar to those in the marine isotope record. However, there are some notable differences between the Baikal and oceanic records. In the marine isotope record, the 41 ka cycle was dominant before 1 Ma and the 100 ka cycle became signiifcant only afterward. Conversely, in the Baikal record, the 100 ka period has appeared continuously throughout the past 2.6 Ma, and no appreciable shift in period is detected. These results suggest that the terrestrial climatic response to orbital forcing, as imprinted in the Baikal sediment, is different from the oceanic response. The 100 ka cycle detected in the Baikal record from before 1 Ma may be attributable to relatively long interglacials with skipping of two or three 41 ka obliquity cycles. This result may support the hypothesis that the 100 ka cycle is paced by the obliquity cycle.

  4. Tectonic and eustatic controls of late quaternary shelf sedimentation along the Central California (Santa Cruz) continental margin: high-resolution seismic stratigraphic evidence

    Science.gov (United States)

    Mullins, Henry T.; Nagel, David K.; Dominguez, Laura L.

    1985-07-01

    A high-resolution "uniboom", seismic stratigraphic investigation of a portion of the central California continental shelf has demonstrated that depositional patterns and sequences are controlled largely by an interplay of glacioeustatic sea-level fluctuations superimposed on local tectonics. Wrench tectonics, associated with active right-lateral shear along the San Gregorio fault zone, and the Pigeon Point Basement High control the location, distribution and overall geometry of depositional sequences via en echelon folding and differential subsidence. Areas of relatively thick and thin late Quaternary sediments conform in large part with structures produced during wrenching. Glacioeustatic sea-level oscillations have also shaped depositional patterns and sequences. Correlation of our seismic stratigraphic data with a southern California continental margin sea-level curve, suggests that during the last glacial maximum, approximately 18,000 yrs ago, a relative lowstand resulted in the erosion of a distinct unconformity upon which late Quaternary sediments have accumulated. A rapid rise of sea level to a relative stillstand, approximately 12,000 yrs ago, produced a concave-up, marine terrace profile across the mid-shelf, that has since been infilled with as much as 22 m of Holocene clastic sediments. A relative drop of sea level, approximately 11,000 yrs ago, allowed sediments to build seaward as a series of prograding clinoforms that form the basal sequences of the late Quaternary sediment fill. The succeeding Holocene transgression partially eroded the top of this earlier regressive sequence, and has now established a typical, wave-graded shelf along which sediments fine in a seaward direction to water depths of 90-100 m. At greater shelf water depths, surface sediments coarsen and appear to be relicts of previous relative sea-level lowstands. The presence of now submerged and buried marine terraces along both the central and southern California continental margins

  5. Mineralogía de arenas y limos en suelos, sedimentos fluviales y eólicos actuales del sector austral de la cuenca Chacoparanense: Regionalización y áreas de aporte Sands and clay mineralogy in soils, fluvial and eolian Present sediments in the southern sector of the Chacoparanense basin: Different regions and source areas

    Directory of Open Access Journals (Sweden)

    M. C. Etchichury

    2004-06-01

    Corrientes provinces allowed to define two zones characterized by two genetically different mineralogical associations. Minerals of volcanic - pyroclastic origin (heavy: green, basaltic and brown hornblende, hypersthene, enstatite, augite, magnetite, hematite, ilmenite, leucoxene, epidote, zoicite, and light: plagioclase, volcanic fragments, pumice and glass shards, quartz, orthoclase are observed over a broad area including whole Buenos Aires and Cordoba provinces, northwestern regions of La Pampa, central and southern Santa Fe and southern Entre Ríos. The provenence of these minerals included the pampean and post-pampean sediments and scarce contribution from volcanic Mesozoic rocks of north Patagonia, Sierras Pampeanas and also Quaternary pyroclastic eruptions. Conversely, a heavy suite of metamorphic provenence (staurolite, kyanite, sillimanite, andalusite, hornblende, epidote, opaques and a light association composed of igneous and metamorphic clast (monocrystalline and polycrystalline quartz, orthoclase,microcline, schists and others of sedimentary origin (quartz arenites is recorded in Corrientes and northern Santa Fe and Entre Ríos provinces. These minerals are coming from older basement rocks outcropping in Brazil and Uruguay and the younger overlain sedimentary succession. The peculiar material distribution is related to the drainage systems and wind pattern. Quartz 30% frecuency isoplet points out the limit between both mineralogical associations.

  6. Mineralogy and Geochemistry from Trollveggen Vent Field Chimneys and Metalliferous Sediments (Mohns Ridge, West Jan Mayen Fracture Zone at 71°N)

    Science.gov (United States)

    Dias, S.; Cruz, I.; Fonseca, R.; Barriga, F. J.; Pedersen, R.

    2010-12-01

    The Jan Mayen vent fields were discovered in the Mohns Ridge during an expedition with the Norwegian research vessel "G.O. Sars" in July 2005. They comprise two main active areas: (1) Soria Moria and (2) Gallionella Garden & Trollveggen. The Trollveggen vent field is located at depths of 700-750 m. Venting takes place mainly through white smoker chimneys with fluid temperatures reaching up to 260-270°C. Here we present mineralogical and geochemical data from vent chimneys and metalliferous sediments collected at the Trollveggen vent field with an ROV. Cross-sections of chimneys present evident mineralogical zonation, showing acicular barite crystals in the outer parts and sulfide enrichments in the interior (Sph + Cpy +/- Py - Po). Sediments are mainly formed by vent fragments but also by minerals precipitated by diffuse fluid circulation, showing a mineral assemblage similar to that of chimneys. Microprobe analyses were obtained both in sulfates and sulphides revealing a particular sphalerite composition, characterized by low Fe (trace metal contents (up to 4%, including Cu, Ag and Au). Geochemical profiles of gravity cores collected in the area surrounding Jan Mayen were also performed in order to investigate the presence of additional hydrothermal activity in the area. Total geochemical analyses showed a slight enrichment in trace metals, such as Cu, Zn and Fe, with exception of one core that reached 85 ppm for Cu, 150 ppm for Zn and 20% for Fe. The metal enrichment in this core suggests hydrothermal activity in the neighboring area.

  7. An integrated geochemical, geophysical and mineralogical study of river sediments in alpine area and soil samples near steel plant, in Austria

    Science.gov (United States)

    Irfan, M. I.; Meisel, T.

    2012-04-01

    Concentration of nickel and chromium in any part of the ecosystem is important for environmental concerns in particular human health due to the reason that some species of them can cause health problem e.g. dermatitis and cancer. Sediment samples collected form a river Vordernberger Bach (Leoben, Austria) in an alpine region and soil samples collected in an area adjacent to steel production unit in same narrow valley were investigated. In previous studies a correlation between magnetic susceptibility values and concentration of nickel and chromium showed that a magnetic susceptibility meter can be used to point out the contaminated areas as in-situ device. The purpose of the whole study is to understand the real (point or diffuse, anthropogenic or geogenic) sources of contamination of soils, water and river sediments through heavy metal deposition. Unseparated, magnetic and non-magnetic fractions of soil samples were investigated for geochemical and mineralogical aspects with XRF, ICP-MS, EMPA, Multi-Functional Kappabridge (MFK1) and laser ablation coupled with ICP-MS. Mineralogical study of sediment samples for several sampling points with higher Ni and Cr content was performed. Sediment samples were sieved below 1.4 mm and then a concentrate of heavy minerals was prepared in the field through panning. Concentrated heavy minerals were then subjected for heavy liquid separation in the laboratory. Separated magnetic and non-magnetic fractions below 0.71/0.1 mm and density greater than 2.9 g/cm3 were selected for mineralogical investigation. The abundance of typical anthropogenic particles, e.g., spherical, tinder, roasted ores, iron and steel mill slag was observed under the microscope. Magnetite (mostly anthropogenic), maghemite, chromspinel, chromite (type I & II), (Ca,Al)-ferrite, wustite, apatite (anthropogenic), olivine mixed crystals, calcium silicate and spinel (anthropogenic) are found in magnetic fraction. Non-magnetic fractions contain hematite, siderite

  8. Late quaternary floodplain sedimentation along the Pomme de Terre River, southern Missouri

    Science.gov (United States)

    Brakenridge, G. Robert

    1981-01-01

    New cross sections and dates from along the Pomme de Terre River clarify the complex local history of valley development and floodplain sedimentation. The observed history begins with a series of ancient bedrock strath terraces that record past bedrock valley positions at 15.5 to more than 58 m above the modern bedrock floor. Each strath is capped by 1-2 m of channel gravel and sand permeated by red clay. Sometime previous to ca. 140,000 yr B.P., a much lower bedrock valley only about 5-6 m above the modern level was excavated. By 140,000 yr B.P., accumulation of red and gray mottled silty clay had commenced, and had reached to 8.5 m above the modern floodplain before 48,900 ± 900 14C yr B.P. Sometime between ca. 49,000 and 45,000 14C yr B.P., erosion caused abandonment of an oxbow meander, and lowered the bedrock valley to about its present depth. Younger yellowish-red and gray mottled silty clay alluvium then began accumulating. This mid-Wisconsinan fill reached to 2.5 m above the modern floodplain sometime before 31,800 ± 1340 14C yr B.P., at which time another erosional phase was in progress. A late Wisconsinan olive clay accumulated between 27,480 ± 1950 and ca. 23,000 14C yr B.P., followed by approximate stability until 13,550 ± 400 14C yr B.P. After stability, an erosional episode began, but by 10,200 ± 330 14C yr B.P., deposition of a distinctive brown clayey silt was underway. This early Holocene fill reached to about the same level as the mid-Wisconsinan fill by 8100 ± 140 14C yr B.P. Erosion occurred between this date and 7490 ± 170 14C yr B.P., but the former floodplain level was rapidly reattained, and was apparently stable until ca. 5000 14C yr B.P. Finally, erosional unconformities and 17 dates from the brown clayey silt, and from younger grayish-brown silty sand underlying the modern floodplain, record subsequent episodes of floodplain erosion at ca. 5000, 2900, 1500 and 350 14C yr B.P. The timing of Pomme de Terre floodplain sedimentary

  9. The Southern Brazilian shelf: general characteristics, quaternary evolution and sediment distribution

    Directory of Open Access Journals (Sweden)

    Michel Michaelovitch de Mahiques

    2010-01-01

    Full Text Available Extending from latitude 34ºS to 22ºS the Southern Brazilian shelf constitutes the only part of the Brazilian shelf with a subtropical to temperate environment. The studies on the different geological aspects of the area began in the 1960's and have recently been reassessed after studies related to the determination of the Economic Exclusive Zone. In terms of morphology, the Southern Brazilian shelf may be divided into three sectors, the São Paulo Bight, the Florianópolis-Mostardas Sector and the Rio Grande Cone, characterized by conspicuous differences in terms of geological determining factors, bathymetry, declivities and the presence of canyons and channels. Despite the existence of hundreds of radiocarbon datings the sea level changes curve of southern Brazil during the Last Glacial Cycle is still a matter of debate. A recent controversy on the Middle and late Holocene sea level changes curve raised the question of the amplitude of the oscillations which occurred in the period. Also, a few but relatively consistent radiocarbon datings suggest the occurrence of a high sea level during Isotope Stage 3. In terms of sedimentary cover the Southern Brazilian shelf exhibits a very strong hydrodynamic control, both latitudinal and bathymetrical. The sector southward from 25ºS is characterized by the influence of the plume of water carrying sediments originating from the Río de La Plata. Actually its presence is conspicuous up to 28ºS, with the area between this latitude and 25ºS constituting a transitional zone. In terms of bathymetry the outer shelf is marked by the "floor-polisher" effect of the Brazil Current, which is responsible for the maintenance of a relict facies in areas deeper than 100 meters.Estendendo-se entre as latitudes 34ºS e 22ºS, a plataforma continental sul-brasileira constitui o único setor que corresponde a um ambiente subtropical a temperado. Os estudos dos diferentes aspectos geológicos da área iniciaram-se na d

  10. Source to sink element geochemistry and clay mineralogy in Lake Towuti, Indonesia: understanding climate-induced controls on sediment composition during the past 60 kyr BP

    Science.gov (United States)

    Morlock, Marina; Vogel, Hendrik; Nigg, Valentin; Hasberg, Ascelina; Melles, Martin; Russell, James M.; Bijaksana, Satria

    2016-04-01

    Lake Towuti is a large (560 km2 surface area; 198 m max. water depth) ultraoligotrophic lake hosted in the East Sulawesi ophiolite, characterised by high iron and very low sulphur contents. The lake is surrounded by several 10s of metres thick deeply weathered laterite soils and closed-canopy rainforest. In May-July 2015, we recovered more than 1000 m of sediment core capturing the entire sediment infill to bedrock in the course of the ICDP Towuti Drilling Project. In the tropics very little is known about the influence of climatic changes on weathering and erosion on glacial-interglacial time-scales. It is expected that varying hydroclimatic conditions will lead to changes in the weathering and erosion rates and greatly influence terrestrial elemental cycling. The direction of change and more quantitative estimates of the rates of changes are, however, unknown. In order to characterise modern erosional processes and element cycling in the lake and its catchment, we collected catchment-characteristic bedrock samples and profiles of their overlying laterites, riverine sediments, and 85 samples of surface sediments from the lake. All samples were analysed for their geochemical and clay-mineralogical (changes in sediment composition, and assess the spatial variability in Lake Towuti. The relationships found in the modern system were then applied to two sediment cores, dating back 30,000 and 60,000 years BP, respectively. The laterite soils in the catchment show a characteristic zonation with high concentrations of Al, Ti, Fe, and Cr in the uppermost horizon, while Mg is enriched in the saprolite zone directly above bedrock. Weathering intensity increases from bedrock (least weathered) across river bedload of the 15 inlets to the sediments in the deepest basin of the lake (most weathered). The largest inlet to Lake Towuti, the Mahalona River, supplies sediments with low Al and high Mg concentrations and exerts a dominant control on the present-day sediment composition

  11. Sequential Extraction Results and Mineralogy of Mine Waste and Stream Sediments Associated With Metal Mines in Vermont, Maine, and New Zealand

    Science.gov (United States)

    Piatak, N.M.; Seal, R.R.; Sanzolone, R.F.; Lamothe, P.J.; Brown, Z.A.; Adams, M.

    2007-01-01

    We report results from sequential extraction experiments and the quantitative mineralogy for samples of stream sediments and mine wastes collected from metal mines. Samples were from the Elizabeth, Ely Copper, and Pike Hill Copper mines in Vermont, the Callahan Mine in Maine, and the Martha Mine in New Zealand. The extraction technique targeted the following operationally defined fractions and solid-phase forms: (1) soluble, adsorbed, and exchangeable fractions; (2) carbonates; (3) organic material; (4) amorphous iron- and aluminum-hydroxides and crystalline manganese-oxides; (5) crystalline iron-oxides; (6) sulfides and selenides; and (7) residual material. For most elements, the sum of an element from all extractions steps correlated well with the original unleached concentration. Also, the quantitative mineralogy of the original material compared to that of the residues from two extraction steps gave insight into the effectiveness of reagents at dissolving targeted phases. The data are presented here with minimal interpretation or discussion and further analyses and interpretation will be presented elsewhere.

  12. Mineralogical and chemical composition of the mud fraction from the surface sediments of Sharm Al-Kharrar, a Red Sea coastal lagoon

    Directory of Open Access Journals (Sweden)

    Ali S. Basaham

    2008-12-01

    Full Text Available Interaction between continental and marine end-members gives rise to thenatural biogeochemical processes in Sharm Al-Kharrar, a lagoon in the arid RedSea region. Twenty-nine surface sediment samples were collected from the areaand their mud fraction analysed for grain size, OC, CaCO$_3$, mineralogy andelemental composition. The mud fraction consisted of a mixture ofsiliciclastic/calcareous materials, dominated by silt size materials andcharacterised by low OC (average 0.71% $pm$0.13; CaCO$_3$ varied widely,with anaverage of 45\\% $pm$18. Concentrations of Al, Fe, Mn, Cu, Ni, Cr, V and Bashoweda wide range of variation throughout the Sharm. The results were normalised toAl and subjected to cluster analysis in order to examine the relations betweenthe mineralogy and the elemental composition. The contents of Al, Fe, Mn, Cu,Ni, Cr, V and Ba appeared to be influenced by the mixing of the twoend-members in addition to the physiochemical processes associated with themixing between episodic freshwater flooding and seawater. Zn was the singleelement that showed a slight departure from the mixing model.

  13. Mineralogy and source rock evaluation of the marine Oligo-Miocene sediments in some wells in the Nile Delta and North Sinai, Egypt

    Science.gov (United States)

    El sheikh, Hassan; Faris, Mahmoud; Shaker, Fatma; Kumral, Mustafa

    2016-06-01

    This paper aims to study the mineralogical composition and determine the petroleum potential of source rocks of the Oligocene-Miocene sequence in the Nile Delta and North Sinai districts. The studied interval in the five wells can be divided into five rock units arranged from the top to base; Qawasim, Sidi Salem, Kareem, Rudeis, and Qantara formations. The bulk rock mineralogy of the samples was investigated using X-Ray Diffraction technique (XRD). The results showed that the sediments of the Nile Delta area are characterized by the abundance of quartz and kaolinite with subordinate amounts of feldspars, calcite, gypsum, dolomite, and muscovite. On the other hand, the data of the bulk rock analysis at the North Sinai wells showed that kaolinite, quartz, feldspar and calcite are the main constituents associated with minor amounts of dolomite, gypsum, mica, zeolite, and ankerite. Based on the organic geochemical investigations (TOC and Rock-Eval pyrolysis analyses), all studied formations in both areas are thermally immature but in the Nile delta area, Qawasim, Sidi Salem and Qantara formations (El-Temsah-2 Well) are organically-rich and have a good petroleum potential (kerogen Type II-oil-prone), while Rudeis Formation is a poor petroleum potential source rock (kerogen Type III-gas-prone). In the North Sinai area, Qantara Formation has a poor petroleum potential (kerogen Type III-gas-prone) and Sidi Salem Formation (Bardawil-1 Well) is a good petroleum potential source rock (kerogen Type II-oil-prone).

  14. The features of the chemical and mineralogical composition and the formation conditions of sediments in the filters and filtrational zones of the oil wells in the Velizhansk water inlet

    Energy Technology Data Exchange (ETDEWEB)

    Lobachev, A.D.; Drydin, V.M.; Sidorenkov, A.I.

    1979-01-01

    Based on a study of the chemical composition of the silt sediment taken from the filters of operational oil wells in the Velizhansk water inlet located in the Tyumen region, where iron hydroxide and calcium carbonate are the primary compounds, the silt deposition conditions are determined. Hydrochloric acid treatment is recommended for cleaning the filters, based on the feature of the chemicals and mineralogical composition of the silt sediment.

  15. Late Quaternary sediment deposition of core MA01 in the Mendeleev Ridge, the western Arctic Ocean: Preliminary results

    Science.gov (United States)

    Park, Kwang-Kyu; Kim, Sunghan; Khim, Boo-Keun; Xiao, Wenshen; Wang, Rujian

    2014-05-01

    Late Quaternary deep marine sediments in the Arctic Ocean are characterized by brown layers intercalated with yellowish to olive gray layers (Poore et al., 1999; Polyak et al., 2004). Previous studies reported that the brown and gray layers were deposited during interglacial (or interstadial) and glacial (or stadial) periods, respectively. A 5.5-m long gravity core MA01 was obtained from the Mendeleev Ridge in the western Arctic Ocean by R/V Xue Long during scientific cruise CHINARE-V. Age (~450 ka) of core MA01 was tentatively estimated by correlation of brown layers with an adjacent core HLY0503-8JPC (Adler et al., 2009). A total of 22 brown layers characterized by low L* and b*, high Mn concentration, and abundant foraminifera were identified. Corresponding gray layers are characterized by high L* and b*, low Mn concentration, and few foraminiferal tests. Foraminifera abundance peaks are not well correlated to CaCO3 peaks which occurred with the coarse-grained (>0.063 mm) fractions (i.e., IRD) both in brown and gray layers. IRDs are transported presumably by sea ice for the deposition of brown layers and by iceberg for the deposition of gray layers (Polyak et al., 2004). A strong correlation coefficient (r2=0.89) between TOC content and C/N ratio indicates that the major source of organic matter is terrestrial. The good correlations of CaCO3 content to TOC (r2=0.56) and C/N ratio (r2=0.69) imply that IRDs contain detrital CaCO3 which mainly originated from the Canadian Arctic Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond to CaCO3 peaks, which suggests that the fine-grained particles in the Mendeleev Ridge are transported from the north coast Alaska and Canada where Mesozoic and Cenozoic strata are widely distributed. Thus, the Beaufort Gyre, the predominant surface current in the western Arctic Ocean, played an important role in the sediment delivery to the Mendeleev Ridge. It is worthy of note that the TOC and CaCO3 peaks are

  16. A record of Late Quaternary continental weathering in the sediment of the Caspian Sea: evidence from U-Th, Sr isotopes, trace element and palynological data

    Science.gov (United States)

    Pierret, M. C.; Chabaux, F.; Leroy, S. A. G.; Causse, C.

    2012-09-01

    This study presents combined mineralogical, chemical, isotopic (87Sr/86Sr and U-Th disequilibria series) and palynological analyses on bulk sediments and on distinct mineral phases (carbonates and clays) from a 10-m-long core drilled in the southern Caspian Sea and containing a Late Pleistocene and Early Holocene record. The data allowed identifying 1) the main variations in sedimentation, 2) the processes causing these variations, 3) the modification of erosion vs weathering, and 4) the influence of climatic and/or Caspian Sea level changes in the region since the Late Pleistocene. The chemical and mineralogical results allowed the division of the sedimentary sequence into three main units and a transition zone. The lower unit (unit U1) primarily consists of silicate and carbonate-rich detritus. Sedimentation characteristics, including observation of detritus in secular equilibrium, are relatively constant within this unit and reflect mechanical erosion in a cold climate. Unit U1 probably corresponds to a glacial period when the vegetation cover was sparse and wind and river transport of pollen were strong. Subsequently, global increase in temperatures has greatly modified the sedimentation in the Caspian Sea south basin. Biogenic sedimentation is higher in units U2 and U3, and detrital inputs varied from unit U1. Variations in detrital input are likely to be caused by decreasing aeolian contribution and by relative changes in river volumes and origins. The study of the bulk sediments, clays and carbonates reflects an increase in chemical weathering since about 10 14C ka BP ago (base of unit U2), in line with an increase in the vegetation cover. Our results suggest an evolution of continental weathering conditions in the catchment area of the Caspian Sea, from dominantly mechanical/physical erosion during the cold period to a continuous increase in weathering since the Lateglacial period, as climate improved, which illustrates the strong relation between climate

  17. Geochemical-mineralogical characteristics of spring sediment of the iron-sulfate mineral water Ljepotica near Srebrenica, RS

    Directory of Open Access Journals (Sweden)

    Dangić Adam V.

    2002-01-01

    Full Text Available The Srebrenica area in Eastern Bosnia (Republika Srpska is characterized by numerous Pb-Zn sulfide ore bodies and several iron-sulfate mineral water springs. The spring Ljepotica appears in the central part of the area and has similar water composition and spring sediment "limonite" mass like nearby the famous medical iron-arsenic water spring Crni Guber. The sequential chemical analysis of iron and XRD-studies of the relative shortly aged spring sediment showed that it is composed by ferrihydrite, jarosite and some goethite. The ratio Fedit/Fetot of 0.76 indicates that jarosite appears as a main constituent, in contrast to the Crni Guber spring sediment in which occurs irregularly and in traces. Trace elements pattern is characterized by appearance of As, Pb, Sb, and Sr as the most abundant (>5000 and up to 1450, 780, and 210 ppm, respectively, small contents of Cr, Cu, Ti, V, and Zn (up to 60 ppm, and traces of Mn, Ni and Sc (below 10 ppm. Chemical analysis of the sediment indicates that jarosite is of the jarosite-hydronium jarosite type.

  18. Glacial meltwater impounding: Evidence from the late Quaternary glaciogenic sediments in the Sangla valley, district Kinnaur, Himachal Pradesh, India

    Indian Academy of Sciences (India)

    R K Ganjoo; M N Koul

    2005-08-01

    Sangla valley is situated at an altitude of ∼3500m above mean sea level and lies in the Kinnaur district of Himachal Pradesh. It is fed by river Baspa, a tributary of river Sutlej, that entrenches through the Quaternary glaciogenic deposits before emerging out of the valley and joining the river Sutlej at Karcham. The unstratified to stratified glaciogenic deposits consist of large boulders to fine silt and are classified into four major depositional facies on the basis of sedimentary texture and depositional environment. The facies — basal conglomerates, debris flow, water/sheet flow and laminites — represents the change in the environment of deposition from glaciofluvial to lacustrine and also the extent of the glacier to the valley floor during late Quaternary.

  19. Petrographic, mineralogical and geochemical characterization of the Serrinha coal waste pile (Douro Coalfield, Portugal) and the potential environmental impacts on soil, sediments and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, J. [Centro de Geologia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Ferreira da Silva, E. [GeoBioTec, Geobiosciences, Geotechnologies and Geoengineering Research Center, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Li, Z.; Ward, C. [School of Biological, Earth and Environmental Sciences, University of New South Wales. Sydney, NSW 2052 (Australia); Flores, D. [Departamento de Geociencias, Ambiente e Ordenamento do Territorio, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

    2010-09-01

    Serrinha is the largest coal waste pile resulting from mining activities in the Douro Coalfield, Portugal. The exploitation of anthracite in tens of small mines caused some environmental impacts, as is the case of the coal waste piles that exist in old mines and adjacent areas. The Serrinha waste pile is essentially made up of 2 million tonnes of shales and carbonaceous shales, deposited in a topographical depression over about 30 years. Despite the environmental restoration accomplished in the Serrinha waste pile, some environmental problems seem to persist. In this study a petrographic, mineralogical and geochemical characterization was done in order to recognize and understand these problems. The materials studied were coal waste, sediments and waters from the drainage system and decanting basins, soils from the surrounding areas, leachates from waste material and neoformed minerals formed at the bottom of the waste pile. The main lithologies (carbonaceous shale and lithic arenite) and coal from the Douro Coalfield were also analyzed. Petrographic analysis shows some evidence of weathering (on organic and inorganic matter) related to the time of exposure to the weathering agents and the easy access of air within the waste pile (due to both the poor compaction and the heterogeneity of the material). Mineralogically, the composition of coal waste material has contributions from both the coal and the associated lithologies. R-type cluster analysis of the waste pile material allows two distinct clusters to be identified. In the first cluster a sulfide fraction is represented by the association of As, Cd, Cu, Pb, Ni and Zn, while Fe clustered with Al, Co, and Ti indicates that some of the Fe and the other elements are likely associated with silicate minerals such as clays. The second cluster, represented by Cr, V, Zr, Rb, REE, Mn, Li and Ba, probably represent a silicate fraction, perhaps detrital accessory minerals. The waste pile material, leachates, soils

  20. Surface (sea floor) and near-surface (box cores) sediment mineralogy in Baffin Bay as a key to sediment provenance and ice sheet variations

    Science.gov (United States)

    Andrews, John T.; Eberl, D.D.

    2011-01-01

    To better understand the glacial history of the ice sheets surrounding Baffin Bay and to provide information on sediment pathways, samples from 82 seafloor grabs and core tops, and from seven box cores were subjected to quantitative X-ray diffraction weight percent (wt.%) analysis of the 2000 m) all show an abrupt drop in calcite wt.% (post-5 cal ka BP?) following a major peak in detrital carbonate (mainly dolomite). This dolomite-rich detrital carbonate (DC) event in JR175BC06 is possibly coeval with the Younger Dryas cold event. Four possible glacial-sourced end members were employed in a compositional unmixing algorithm to gain insight into down core changes in sediment provenance at the deep central basin. Estimates of the rates of sediment accumulation in the central basin are only in the range of 2 to 4 cm/cal ka, surprisingly low given the glaciated nature of the surrounding land.

  1. Bryophyte and pteridophyte spores and other palynomorphs in quaternary marine sediments from Campos Basin, southeastern Brazil: Core BU-91-GL-05

    Directory of Open Access Journals (Sweden)

    Aline Gonçalves de Freitas

    2015-06-01

    Full Text Available This paper presents morphological descriptions and ecological data of cryptogam spores and other non-pollen palynomorphs from Quaternary sediments of Campos Basin, Rio de Janeiro, SE Brazil. The ages were derived from biostratigraphy of planktonic foraminifers and two radiocarbon dates, and suggest that sediment deposition started in the last 140,000 years BP. Thirty different types of palynomorphs were identified, described, and photographed: two bryophyte spores (sensu lato; 21 pteridophyte spores; four freshwater microalgae; onePseudoschizaea; and two microfungi. Some of the identified spores (Sphagnum, Blechnum, Cyatheaceae, Dennstaedtiaceae, Lycopodiella, Microgramma, Polypodium, Acrostichum, Pityrogramma, and Lygodium are related to the modern flora found on the northern coast of Rio de Janeiro State, at the Restinga of Jurubatiba, from vegetation types such as shrub swamp/coastal swamp formation, seasonally flooded forest, Clusia and Ericaceae woods, and disturbed vegetation. The freshwater microalgae and the microfungi are also presently recorded from the coastal lagoons of this region. The high spore concentration in slope sediments reflects the intense terrigenous influx, caused by a relative low sealevel during glacial stages. Palynological analysis suggests the presence of taxa from flooded forests and humid areas in the coastal plain during glacial and interglacial stages of the Late Pleistocene.

  2. Multivariate statistic and time series analyses of grain-size data in Quaternary sediments of Lake El'gygytgyn, NE Russia

    Directory of Open Access Journals (Sweden)

    A. Francke

    2013-01-01

    Full Text Available Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the ICDP Lake El'gygytgyn Drilling Project obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to Principal Component Analyses (PCA, the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser grain sizes in the lake center is supposed to be caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment, and the availability of water as transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice-cover with sedimentation being restricted to seasonal moats and vertical conducts through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight in the frequency of the grain-size data showed grain-size variations predominately on Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary imply that climate conditions at Lake El'gygytgyn are mainly triggered by global glacial/interglacial variations (eccentricity, obliquity and local insolation forcing (precession, respectively.

  3. Glaciomarine sedimentation and bottom current activity on the north-western and northern continental margins of Svalbard during the late Quaternary

    Science.gov (United States)

    Chauhan, Teena; Noormets, Riko; Rasmussen, Tine L.

    2016-04-01

    Palaeo-bottom current strength of the West Spitsbergen Current (WSC) and the influence of the Svalbard-Barents Sea Ice Sheet (SBIS) on the depositional environment along the northern Svalbard margins are poorly known. Two gravity cores from the southern Yermak Plateau and the upper slope north of Nordaustlandet, covering marine isotope stage (MIS) 1 to MIS 5, are investigated. Five lithofacies, based on grain size distribution, silt/clay ratio, content and mean of sortable silt (SS), are distinguished to characterise the contourite-dominated sedimentary environments. In addition, depositional environments are described using total organic carbon (TOC), total sulphur (TS) and calcium carbonate (CaCO3) contents of sediments. Facies A, containing coarse SS, suggests strong bottom current activity and good bottom water ventilation conditions as inferred from low TOC content. This facies was deposited during the glacial periods MIS 4, MIS 2 and during the late Holocene. Facies B is dominated by fine SS indicating weak bottom current and poor ventilation (cf. high TOC content of 1.2-1.6%), and correlates with the MIS 4/3 and MIS 2/1 transition periods. With an equal amount of clay and sand, fine SS and high content of TOC, facies C indicates reduced bottom current strength for intervals with sediment supply from proximal sources such as icebergs, sea ice or meltwater discharge. This facies was deposited during the last glacial maximum. Facies D represents mass-flow deposits on the northern Svalbard margin attributed to the SBIS advance at or near the shelf edge. Facies E sediments indicating moderate bottom current strength were deposited during MIS 5 and MIS 3, and during parts of MIS 2. This first late Quaternary proxy record of the WSC flow and sedimentation history from the northern Svalbard margin suggests that the oceanographic conditions and ice sheet processes have exerted first-order control on sediment properties.

  4. Novel imaging techniques, integrated with mineralogical, geochemical and microbiological characterizations to determine the biogeochemical controls on technetium mobility in FRC sediments

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan R. Lloyd

    2009-02-03

    -200 MBq; half life 6 hours) and its mobility was monitored using a {gamma}-camera. Incorporation of low concentrations of the long-lived 99Tc gave a tracer that can be followed by scintillation counting, should the metastable form of the radionuclide decay to below detection limits before the end of the experiment (complete immobilization or loss of the Tc from the column). After the Tc was reduced and immobilized, or passed through the system, the columns were dismantled carefully in an anaerobic cabinet and the pore water geochemistry and mineralogy of the columns profiled. Microbial community analysis was determined, again using molecular and culture-dependent techniques. Experimental results were also modeled using an established coupled speciation and transport code, to develop a predictive tool for the mobility of Tc in FRC sediments. From this multidisciplinary approach, we hoped to obtain detailed information on the microorganisms that control the biogeochemical cycling of key elements at the FRC, and we would also be able to determine the key factors that control the mobility of Tc at environmentally relevant concentrations at this site.

  5. Paleo-fluid flow in folded, poorly lithified Quaternary sediments revealed by diagenetic concretions developed during the growth of Quattro Castella Anticline (Northern Apennines, Italy)

    Science.gov (United States)

    Pizzati, Mattia; Balsamo, Fabrizio; Iacumin, Paola; Swennen, Rudy; Storti, Fabrizio

    2017-04-01

    Diagenetic concretions and mineral masses may provide a useful tool to better understand paleo-fluid flows in transforming porous media. Moreover, the selective cementation responsible of diagenetic alterations formation, plays a key role in diminishing sediments porosity and permeability and hence reservoir quality. In compressive settings of a fold-and-thrust-belt, the presence of deep or blind thrusts could lead to the generation of folds which may influence syn-kinematic sedimentation, deep fluids migration and shallow fluid flow pattern. In this contribution we present a multidisciplinary field and laboratory study on carbonate concretions developed in Quaternary poorly lithified, shallow marine syn-kinematic sediments of the Quattro Castella Anticline in Northern Apennines (Italy). The study site is located along the Enza River, where shallow marine to continental sediments are exposed along the forelimb of the fold nucleated during Late Miocene and still active today. Field mapping was aimed to link bedding attitude of syn-kinematic sediments with the geometry, arrangement, shape and size of concretionary bodies. The studied concretions are both tabular (i.e. parallel to sediment bedding) and elongate single or coalescent concretionary bodies (i.e. plunging at different angle to bedding dip throughout the stratigraphic section). Concretions dimensions range from a few centimeters in single elongate concretions, up to a few meters in tabular and coalescent ones. In situ permeability measurements and laboratory grain size analyses were performed along the studied section to constrain the petrophysical properties of sediments hosting carbonate concretions. Carbon and oxygen stable isotopes analyses on carbonate concretions (performed both on hand specimens and also on thin sections), together with petrographic and cathodoluminescence observations, were used to better constrain the diagenetic environment in which calcite precipitation occurred. Our results

  6. Geochemistry and mineralogy approaches to characterize brick and its lake sediments sources: Antioch Roman City (Southern Turkey)

    OpenAIRE

    El Ouahabi, Meriam; Hubert, Aurelia; Benjelloun, Yacine; Chene, Grégoire; Strivay, David; De Sigoyer, Julia; Pamir, Hatice; Karabacak, Volkan; Fagel, Nathalie

    2016-01-01

    The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active Dead Sea fault and the East Anatolian fault. During the Roman period, the Amik Plain was more densely occupied than at any time in its history [1]. The study focuses on the bricks and the lake sediments characterization in order to determine the source area as well as the technical productio...

  7. Mineralogical-chemical composition and environmental risk potential of pond sediments at the geothermal field of Los Azufres, Mexico

    Science.gov (United States)

    Birkle, P.; Merkel, B.

    2002-01-01

    Since 1982, estimated amounts of 9,400 t, 15,000 kg, 720 kg and 105 kg of Si, Fe, As and Cs respectively have accumulated at the bottom of 18 evaporation ponds as part of the geothermal production cycle at Los Azufres. This accumulation is caused by precipitation of brine solutes during the evaporation of 10% of the total pond water volume before its re-injection into the reservoir. Extraction experiments with pond precipitates and geochemical simulations with the PHREEQC program indicate the high solubility of most precipitates under natural environmental conditions. The comparisons with the primary brine composition indicate that less than 1% of most dissolved brine solutes, except for Co, Cu, Mn, Pb, Ag, Fe and Si, are accumulated at the pond bottom. Arsenic has maximum values of 160 mg/kg in the pond sediments, and Mo, Hg and Tl also exceed international environmental standards for contaminated soils. Elevated concentrations and the mobility potential of several metals and non-metals require the application of remediation techniques for the final disposal of the sediments in the future.

  8. Effects of grain size, mineralogy, and acid-extractable grain coatings on the distribution of the fallout radionuclides 7Be, 10Be, 137Cs, and 210Pb in river sediment

    Science.gov (United States)

    Singleton, Adrian A.; Schmidt, Amanda H.; Bierman, Paul R.; Rood, Dylan H.; Neilson, Thomas B.; Greene, Emily Sophie; Bower, Jennifer A.; Perdrial, Nicolas

    2017-01-01

    Grain-size dependencies in fallout radionuclide activity have been attributed to either increase in specific surface area in finer grain sizes or differing mineralogical abundances in different grain sizes. Here, we consider a third possibility, that the concentration and composition of grain coatings, where fallout radionuclides reside, controls their activity in fluvial sediment. We evaluated these three possible explanations in two experiments: (1) we examined the effect of sediment grain size, mineralogy, and composition of the acid-extractable materials on the distribution of 7Be, 10Be, 137Cs, and unsupported 210Pb in detrital sediment samples collected from rivers in China and the United States, and (2) we periodically monitored 7Be, 137Cs, and 210Pb retention in samples of known composition exposed to natural fallout in Ohio, USA for 294 days. Acid-extractable materials (made up predominately of Fe, Mn, Al, and Ca from secondary minerals and grain coatings produced during pedogenesis) are positively related to the abundance of fallout radionuclides in our sediment samples. Grain-size dependency of fallout radionuclide concentrations was significant in detrital sediment samples, but not in samples exposed to fallout under controlled conditions. Mineralogy had a large effect on 7Be and 210Pb retention in samples exposed to fallout, suggesting that sieving sediments to a single grain size or using specific surface area-based correction terms may not completely control for preferential distribution of these nuclides. We conclude that time-dependent geochemical, pedogenic, and sedimentary processes together result in the observed differences in nuclide distribution between different grain sizes and substrate compositions. These findings likely explain variability of measured nuclide activities in river networks that exceeds the variability introduced by analytical techniques as well as spatial and temporal differences in erosion rates and processes. In short, we

  9. Provenance of eastern Magallanes foreland basin sediments: Mineralogical and geochemical analyses reveal Paleogene tectonic unroofing of the Fuegian Andes

    Science.gov (United States)

    Zahid, Khandaker

    Though southern South America and the Antarctic Peninsula were previously connected through a Paleozoic-Mesozoic subduction system on the western margin of Gondwana, this connection was tectonically disrupted in the Cenozoic by forming the Drake Passage in the Scotia Sea. Heavy mineral composition data from the eastern Magallanes basin of southernmost South America indicate that Campanian to middle Eocene sediments had a mafic/ophiolitic provenance which is interpreted as being derived from the Patagonian-Fuegian magmatic arc and the mafic floor of the preceding Rocas Verdes marginal basin. Upper middle Eocene to lower Miocene heavy minerals, on the other hand, indicate a metamorphic/metasedimentary provenance, which suggest being derived from the Cordillera Darwin metamorphic complex. While the rare earth element patterns of all of these samples are typical to those of average post-Archean upper continental crustal types, the younger middle-upper Eocene and lower Oligocene samples contain a higher concentration of the light REEs (LaN/SmN) ratio compared to the older upper Cretaceous to middle Eocene samples suggesting an eastern Andean metamorphic complex provenance for younger sediments. Trace elements plot of stratigraphically older samples exhibit a lower Th/Sc ratio compared to the younger samples suggesting a mafic origin. Nd isotope data show a shift in epsilonNd values from a less negative to a more negative value also during the middle to late Eocene. Together, these data indicate an abrupt shift in sediment provenance in middle to late Eocene time, thereby corroborating recent interpretations of the basin's detrital-zircon geochrononology and thermochronology, and providing further support for temporal and possibly genetic relationships between development of the Patagonian orocline, the opening of Drake Passage and the Oi-1 glaciation of Antarctica. Quantifying the relative abundance of different framework mineral components of sandstone is a common

  10. Quaternary phosphorites off the southeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Michard, A.; Naqvi, S.W.A.; Boettcher, M.E.; Krishnaswamy, R.; Thamban, M.; Natarajan, R.; Borole, D.V.

    Detailed petrological, mineralogical, geochemical and radiogenic (U, Sr, Nd) and stable isotope (C, O, S) studies have been carried out on the Quaternary phosphorites of the continental margin off Chennai, southeast coast of India...

  11. Sedimentary ancient DNA and pollen reveal the composition of plant organic matter in Late Quaternary permafrost sediments of the Buor Khaya Peninsula (north-eastern Siberia)

    Science.gov (United States)

    Hildegard Zimmermann, Heike; Raschke, Elena; Saskia Epp, Laura; Rosmarie Stoof-Leichsenring, Kathleen; Schwamborn, Georg; Schirrmeister, Lutz; Overduin, Pier Paul; Herzschuh, Ulrike

    2017-02-01

    Organic matter deposited in ancient, ice-rich permafrost sediments is vulnerable to climate change and may contribute to the future release of greenhouse gases; it is thus important to get a better characterization of the plant organic matter within such sediments. From a Late Quaternary permafrost sediment core from the Buor Khaya Peninsula, we analysed plant-derived sedimentary ancient DNA (sedaDNA) to identify the taxonomic composition of plant organic matter, and undertook palynological analysis to assess the environmental conditions during deposition. Using sedaDNA, we identified 154 taxa and from pollen and non-pollen palynomorphs we identified 83 taxa. In the deposits dated between 54 and 51 kyr BP, sedaDNA records a diverse low-centred polygon plant community including recurring aquatic pond vegetation while from the pollen record we infer terrestrial open-land vegetation with relatively dry environmental conditions at a regional scale. A fluctuating dominance of either terrestrial or swamp and aquatic taxa in both proxies allowed the local hydrological development of the polygon to be traced. In deposits dated between 11.4 and 9.7 kyr BP (13.4-11.1 cal kyr BP), sedaDNA shows a taxonomic turnover to moist shrub tundra and a lower taxonomic richness compared to the older samples. Pollen also records a shrub tundra community, mostly seen as changes in relative proportions of the most dominant taxa, while a decrease in taxonomic richness was less pronounced compared to sedaDNA. Our results show the advantages of using sedaDNA in combination with palynological analyses when macrofossils are rarely preserved. The high resolution of the sedaDNA record provides a detailed picture of the taxonomic composition of plant-derived organic matter throughout the core, and palynological analyses prove valuable by allowing for inferences of regional environmental conditions.

  12. Environmental magnetic studies on some Quaternary sediments of varied depositional settings in the Indian sub-continent

    Digital Repository Service at National Institute of Oceanography (India)

    Sangode, S.J.; Sinha, R.; Phartiyal, B.; Chauhan, O.S.; Mazari, R.K.; Bagati, T.N.; Suresh, N.; Mishra, S.; Kumar, R.; Bhattacharjee, P.

    Depo sitional settin g D e positional en vironmen t, me an annu al precip itation and tempe rature Siwa lik (Sf) C24 18–0.5 Ma (Sam pling done for C24 2–0.5 Ma inte rval) 32 1 N77 1 E App rox. 3800 m thick comb ination of Chann el sandsto ne, overb ank... a 32 1 N77 1 E App rox. 50 m thic kness of friable sand-silt and mud sequen ce Siwa liks, Lower Tertiarie s and Lesse r Himalayan sediments and met asedimen ts Inte rmonta ne bas in w ith allu vial fan sedimentation (100– 600) msl Fresh wat er flu...

  13. Process mineralogy IX

    Energy Technology Data Exchange (ETDEWEB)

    Petruk, W.; Hagni, R.D.; Pignolet-Brandom, S.; Hausen, D.M. (eds.) (Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada))

    1990-01-01

    54 papers are presented under the headings: keynote address; process mineralogy applications to mineral processing; process mineralogy applications to gold; process mineralogy applications to pyrometallurgy and hydrometallurgy; process mineralogy applications to environment and health; and process mineralogy applications to synthetic materials. Subject and author indexes are provided. Three papers have been abstracted separately.

  14. Geomorphic evolution and sediment partitioning in the Tista Fan and Barind Tract areas, NW Bangladesh, during the Late Quaternary

    Science.gov (United States)

    Grimaud, J. L.; Grall, C.; Paola, C.; Goodbred, S. L., Jr.; Hossain, S.; Sincavage, R.; Pickering, J.; Steckler, M. S.; Seeber, L.; Cojan, I.; Franke, C.

    2016-12-01

    Characterizing surface dynamics at the input of deltas is key for understanding the behavior of rivers as well as the large scale partitioning of their sediments which has implications on stratigraphic architectures and delta-surface evolution. Indeed, the ability of a river system to either efficiently migrate laterally or to persist at a single location through time has repercussions downstream. At the front of mountain ranges, underlying surface deformation and transverse sediment delivery from large alluvial fans (megafans) can steer rivers thus affecting their behavior. In this study, we are interested in the area of NW Bangladesh that is bounded by the Brahmaputra and Ganges rivers (Barind Tract and Tista Fan). We use field reconnaissance as well as a survey of 70 boreholes to characterize surface geomorphology and subsurface deposits. Bulk sediment Sr measurements have enabled us to identify provenance and map the evolution of the Tista Fan boundaries through the Holocene. We find that these boundaries are overall stable despite some changes through time to the east. The distribution of soils and paleosols shows distinctive patterns between the Tista Fan area and the Barind Tract: while the former shows the alternations of soils with various degrees of weathering and fine to coarse sand bodies, the latter forms a more consistently weathered sand accumulation capped by outcropping paleosols. Borehole samples show different types of paleosols between the East Barind Tract and the West Barind Tract, which forms a relative topographic high incised by both the Ganges and Tista rivers. We then analyze both sediment partitioning and geomorphic evolution with emphasis on the geometry of deep-structures. We combine gravity analysis and 2D flexural models that account for differential loading associated to both the tectonics (of the Himalaya Front mainly) and the sedimentation (of the Tista Fan and the Brahmaputra valley). We show that the Barind Tract is under

  15. A record of Quaternary humidity fluctuations on the NE Tibetan Plateau based on magnetic susceptibility variations in lacustrine sediments of the Qaidam Basin

    Science.gov (United States)

    Herb, Christian; Koutsodendris, Andreas; Zhang, Weilin; Appel, Erwin; Pross, Jörg; Fang, Xiaomin

    2013-04-01

    Magnetic susceptibility (?) and other magnetic proxies play an important role in paleoclimatic studies as they hold the potential for high-resolution records of past environmental change. Nevertheless, it is necessary to understand the cause of the variation in magnetic proxies by comparing them to more direct climate proxies such as pollen or stable isotopes. In this study we have compiled a high-resolution magnetic proxy dataset of the ca. 940-m-long core SG-1, which was drilled in the lacustrine sediments of the western Qaidam Basin on the northeastern Tibetan Plateau. Our record spans the entire Quaternary (~2.8 to 0.1 Ma). The magnetic susceptibility record is compared to the Artemisia/Chenopodiaceae (A/C) ratio, which is used to discriminate between dry and more humid phases in the Qaidam Basin, based on (i) 41 samples spanning the Middle Pleistocene Transition (MPT; ~1 Ma BP) and (ii) additional 40 samples selected from intervals of minimum and maximum ? values throughout the core. For the drill core SG-1, we observe a high correlation of the A/C ratio with ? results: minima of ? correspond to maxima of the A/C ratio (representing more humid phases) and vice versa. Additionally, spectral analysis of the ? record shows the emergence of the 100-ka Milankovitch cycle after the MPT. This testifies to the fact that cyclic variation of ? represents a response to global climate change.

  16. Full-vector paleomagnetic secular variation records from latest quaternary sediments of Lake Malawi (10.0°S, 34.3°E)

    Science.gov (United States)

    Lund, Steve; Platzman, Ellen; Johnson, Tom

    2016-07-01

    We have conducted a paleomagnetic study of Late Quaternary sediments from Lake Malawi, East Africa, in order to develop a high-resolution record of paleomagnetic secular variation (PSV). This study has recovered PSV records from two cores (3P, 6P) in northern Lake Malawi (10.0°S, 34.3°E). The PSV appears to be recorded in fine-grained detrital magnetite/titanomagnetite grains. Detailed af demagnetization of the natural remanence (NRM) shows that a distinctive characteristic remanence (ChRM) is demagnetized from ∼20 to 80 mT, which decreases simply toward the origin. The resulting directional PSV records for 3P and 6P are easily correlatable with 29 distinct inclination features and 29 declination features. The statistical character of the PSV in both cores is consistent with Holocene PSV noted at other Holocene equatorial sites. Radiocarbon dating of the cores is based on 18 independent radiocarbon dates and four dated stratigraphic horizons that can be correlated into each core. The final directional PSV time series cover the last 24,000 years with an average sediment accumulation rate of ∼30 cm/kyr. We have also developed a relative paleointensity estimate for these PSV records based on normalizing the NRM (after 20 mT af demagnetization) by the SIRM (after 20 mT af demagnetization). Changing sedimentation patterns complicate any attempt to develop a single paleointensity record for the entire core lengths. We have developed a relative paleointensity record for the last 6000 years that has 14 correlatable features including 5 notable peaks in intensity. Three of these peaks are synchronous with paleointensity highs farther north in SE Europe/SW Asia/Egypt but two of the peaks are at times of low paleointensity farther north. We interpret this to indicate that Lake Malawi (10°S) is at least partly under the influence of a different flux-regeneration region of the outer-core dynamo. A relative paleointensity record was also developed for ∼11,000-24,000 YBP

  17. Changes of planktonic and benthic foraminiferal assemblages in upper quaternary sediments of the Deryugin Basin, Sea of Okhotsk

    Science.gov (United States)

    Khusid, T. A.; Belyaeva, N. V.; Demina, L. L.; Domanov, M. M.; Chekhovskaya, M. P.

    2013-03-01

    The analysis of foraminiferal assemblages in sediments that were deposited during the last 30 kyr revealed similar patterns in their distribution in the central and marginal parts of the Deryugin Basin. The similar composition of foraminifers through the entire basin implies similarity in natural environments within its limits. The absence of benthic foraminifers or extreme impoverishment of the assemblages during the maximum of the last glaciation could result from a combination of several factors: drastic decrease in bioproductivity due to general cooling, development of bottom anoxia, and presumably unfavorable influence of seeps on geochemical parameters of bottom waters. The weak activity of barite-methane seeps in the central part of the basin during the Holocene is evident from some variations in the structure of benthic foraminiferal assemblages against the background of their similar taxonomic compositions.

  18. An investigation of upland erosion and sources of fine-sediment using aerial and terrestrial LiDAR, mineralogy, geochemistry, and particle-size, Humbug Creek and Malakoff Diggings State Historic Park, California

    Science.gov (United States)

    Curtis, J.; Alpers, C. N.; Howle, J.; Monohan, C.; Ward, J.; Bailey, T. L.; Walck, C.

    2015-12-01

    One of the largest hydraulic mines (1.6 km2) is located in California's Sierra Nevada within the Humbug Creek watershed and Malakoff Diggins State Historic Park (MDSHP). Previous work indicates typical annual discharge from Humbug Creek of > 500,000 kg of sediment and > 100 g of mercury. This study uses photogrammetry and repeat high-resolution topographic surveys to quantify erosion rates and geomorphic processes, and sediment "fingerprinting" to quantify contributions of fine-sediment sources. The headwaters of Humbug Creek are underlain by volcanic mudflows, whereas MDSHP's denuded and dissected landscape is composed of weathered auriferous sediments susceptible to chronic rill and gully erosion with block failures and debris flows occurring in more cohesive terrain. Aerial LiDAR (November 2014) was used to create a 1-meter digital elevation model (DEM); photogrammetry will be used to create a pre-1997 DEM from historic aerial photographs. DEM differencing will provide an integrated estimate of long-term erosion averaged over ~20 years in unvegetated areas. Finer-resolution (1-cm) terrestrial LiDAR (T-LiDAR) scans were made in late 2014 at four pit locations and will be repeated in the fall of 2015 and 2016. The T-LiDAR time series will provide annual erosion rates under modern conditions, allowing assessment of relative contributions from shallow surface processes and deeper gravity-driven processes. In 2014‒15 we collected storm runoff and in-situ hillslope samples. Sediment fingerprints (mineralogy, major elements, trace elements, and particle size) for source sediments will be used to assess relative contributions from fine-sediment sources using a statistical mixing model. We will present our approach, preliminary results, and discuss how this study supports selection and implementation of management and remediation strategies to ameliorate the discharge of sediment and mercury and mitigate downstream water-quality impacts.

  19. Partitioning the Quaternary

    Science.gov (United States)

    Gibbard, Philip L.; Lewin, John

    2016-11-01

    We review the historical purposes and procedures for stratigraphical division and naming within the Quaternary, and summarize the current requirements for formal partitioning through the International Commission on Stratigraphy (ICS). A raft of new data and evidence has impacted traditional approaches: quasi-continuous records from ocean sediments and ice cores, new numerical dating techniques, and alternative macro-models, such as those provided through Sequence Stratigraphy and Earth-System Science. The practical usefulness of division remains, but there is now greater appreciation of complex Quaternary detail and the modelling of time continua, the latter also extending into the future. There are problems both of commission (what is done, but could be done better) and of omission (what gets left out) in partitioning the Quaternary. These include the challenge set by the use of unconformities as stage boundaries, how to deal with multiphase records in ocean and terrestrial sediments, what happened at the 'Early-Mid- (Middle) Pleistocene Transition', dealing with trends that cross phase boundaries, and the current controversial focus on how to subdivide the Holocene and formally define an 'Anthropocene'.

  20. Quaternary sediment dynamics in the Belgica mound province, Porcupine Seabight: ice-rafting events and contour current processes

    Science.gov (United States)

    van Rooij, D.; Blamart, D.; Richter, T.; Wheeler, A.; Kozachenko, M.; Henriet, J.-P.

    2007-02-01

    The Belgica cold-water coral banks on the eastern slope of the Porcupine Seabight are closely associated with bottom currents. In order to better understand the local temporal and spatial characteristics, as well as the palaeoclimatologic influences, a 26 m long core, taken on a small contourite drift, was studied. This sediment record of approximately 100 ka BP reveals new insights into the regional glacial and sedimentary processes, which are intrinsically linked to several geological, climatological, biological and hydrodynamic variables. The glacial sequences in the core contain six ice-rafting events (IRE). They are comparable with the North Atlantic Heinrich Events, although their characteristics show dominant influences from the proximal British-Irish Ice Sheet (BIIS). These IRE have a low magnetic susceptibility and are deposited during two or three ice-rafting pulses. The record of ice-rafting suggests a millennial-scaled BIIS destabilisation and confirms the start of a final retreat about 25 ka ago. Additionally, the glacial sequence corresponds to a muddy contourite, influenced by bottom-current strength variations during interstadials, possibly triggered by sporadic reintroductions of Mediterranean Outflow Water in a glacial North Atlantic Ocean. The interglacial sequence features an 11-m thick deep-water massive sand unit, probably deposited under a high-energy bottom-current regime.

  1. Use of OSL dating to establish the stratigraphic framework of Quaternary eolian sediments, Anton scarp upper trench, Northeastern Colorado High Plains, USA

    Science.gov (United States)

    Mahan, S.A.; Noe, D.C.; McCalpin, J.P.

    2009-01-01

    This paper contains the results of the optically stimulated luminescence (OSL) dating used to establish stratigraphic ages and relationships of eolian sediments in a trench in northeastern Colorado, USA. This trench was located in the upper face of the Anton scarp, a major topographic lineament trending NW-SE for a distance of 135 km, in anticipation of intersecting near-surface faulting. The trench was 180 m long, 4.5-6.0 m deep, and exposed 22 m of stratigraphic section, most of which dipped gently west and was truncated by gulley channeling at the face of the scarp. No direct evidence of faulting was found in the upper trench. The stratigraphy from the trench was described, mapped and dated using OSL on quartz and potassium feldspar, and 14C obtained from woody material. OSL dating identified two upper loess units as Peoria Loess and Gilman Canyon Loess, deposited between 16 and 30 ka ago. The bottom layers of the trench were substantially older, giving OSL ages in excess of 100 ka. These older ages are interpreted as underestimates, owing to saturation of the fast component of OSL. Using OSL and 14C dating, we can constrain the erosion and down cutting of the scarp face as occurring between 16 and 5.7 ka. As the trenching investigation continues in other parts of the scarp face, the results of this preliminary study will be of importance in relating the ages of the strata that underlie different parts of the scarp, and in determining whether Quaternary faulting was a mechanism that contributed to the formation of this regional geomorphic feature.

  2. Paleoclimate change recorded in the red earth and brown-yellow sediment of Late Quaternary for northeastern part of Guangdong Province, south to the Nanling Mountains, China

    Institute of Scientific and Technical Information of China (English)

    LI BaoSheng; NIU DongFeng; YANG Yi; WEN XiaoHao; DAVID DianZhang; QIU ShiFan; DONG YüXiang; LI ZhiWen; DU ShuHuan; QIU XianJiao; LI HouXin

    2008-01-01

    The paleoenvironment indicated by the geochronology, major oxides-SiO2, AI203 and TOFE (Fe203 +FeO), and CIA (Chemical Index of Alteration) value of the red earth and brown-yellow silt primarily characterized by the Linjiang stratigraphic section, based on the geological investigation of Late Quaternary along the river banks of northeastern part of China's Guangdong Province, south to the Nanling Mountains, allow us to hypothesize that the red earth on the first terrace in northeastern part of Guangdong belongs to reticulated red clay developed in a hot-wet environment of the last interglacial period (132-73 ka BP), similar to the monsoon environment in the northern margin of modern tropical zone, while the overlying brown-yellow silt layer mainly accumulated in a monsoon environment of warm temperate zone in the last glacial period (73-11 ka BP), with the aeolian sand LJ3 representing an extreme period of worsening climate. Such a hypothesis corresponds well with predecessors' research on the paleoenvironment indicated by abundant fossils in both south and east to the Nanling Mountains. Hence, it follows that the bioclimatic zone did experience a large and rapid vicissitude in northeastern part of China's Guangdong Province, and even in the full extent of the region south to the Nanling Mountains from the last interglacial period to the last glacial period, with the red earth being replaced by the brown-yellow silty sediment, and even maybe with the Ailuropoda-Stegodon Fauna being replaced by the Penghu Fauna. This study may provide an important geological demonstration for the environmental response to global change in China's low latitudes on a 10 ka scale.

  3. Time-integrated 3D approach of late Quaternary sediment-depocenter migration in the Tagus depositional system: From river valley to abyssal plain

    NARCIS (Netherlands)

    Vis, G.J.; Kasse, C.; Kroon, D.; Vandenberghe, J.; Jung, S.; Lebreiro, S.M.; Rodrigues, T.

    2016-01-01

    Quantification of sediment volumes in continental to deep ocean basins is key to understanding processes of sediment distribution in source-to-sink depositional systems. Using our own and published data we present the first quantification of sediment-volume changes in basins along the course of a ma

  4. Forsmark site investigation. Investigation of marine and lacustrine sediment in lakes. Field data 2003

    Energy Technology Data Exchange (ETDEWEB)

    Hedenstroem, Anna [SGU, Uppsala (Sweden)

    2003-04-01

    The aim of this activity is to describe the aerial and stratigraphical distribution of marine and lacustrine sediment i.e. sediment overlaying the glacial till and/or bedrock surface, in lakes in the Forsmark area. The investigation is carried out within areas where mapping of unconsolidated Quaternary deposits is presently carried out. Since small and shallow lakes cover a large part of the region, this work will give important information on the distribution and stratigraphy of sedimentary deposits not included in the regular mapping of unconsolidated Quaternary deposits within the site investigation programme. Samples were also collected for laboratory analyses of grain size distribution, mineralogical composition as well as the total content of C, N and S and calcium carbonate. The analyses will be carried out on selected samples of representative sedimentary units in order to characterise the chemical and physical properties of the unconsolidated deposits. The analytical data will be useful for the hydrogeological modelling and for models of the Quaternary evolution of the area. The mineralogical analyses of clay may provide information on the origin of the clay particles. One stratigraphic sequence from Lake Eckarfjaerden will be stored for later analyses, e.g. pollen analysis. This report includes field data from spring 2003. Together, the field data and the forthcoming results from the laboratory analyses will form the basis for construction of stratigraphical profiles to be presented in a following report in the fall 2003.

  5. Mineralogy of Holocene Sediments from the Southwestern Black Sea Shelf (Turkey) in Relation to Provenance, Sea-level and Current Regimes

    Institute of Scientific and Technical Information of China (English)

    Emel BAYHAN; Mustafa ERG(I)N; Abidin TEMEL; Seref KESK(I)N

    2005-01-01

    Grain size and mineral composition of core sediments were used to investigate influences of various terrestrial and marine conditions,which have prevailed on the southwestern Black Sea shelf during the Holocene.Siliciclastic mud with small amounts of sand and gravel from nearby coastal hinterland is the principal sediment type,whereas sediments deposited near the shelf edge and the (I)stanbul Strait and off the Duru Lake (a paleo-river mouth)constitued large quantities of sand and gravel of both biogenic and terrigenic origin.Variable amounts of aragonite,1 nm-micas,quartz,feldspars,calcite and dolomite constitute the dominant non-clay minerals in bulk sediments.The clay mineral assemblage in the < 2 μm fraction is made up of smectite,illite,kaolinite and chlorite.Aragonite and calcite are mainly derived from benthic accumulations,whereas feldspars (mainly plagioclase) and smectite reflect magmaticvolcanic provenance and the distribution of 1 nm-micas and chlorite correlate with nearby metamorphic sources onland.Nevertheless,grain size and mineral distribution generally indicate a combination of effects of wind and wave climate,longshore and offshore cyclonic currents,changing sea-level stands and nearby source rock and morphological conditions.It is also suggested that at least part of clay minerals could be derived from the northwesterly Danube River input.

  6. Identifying the pollen of an extinct spruce species in the Late Quaternary sediments of the Tunica Hills region, south-eastern United States

    Science.gov (United States)

    Luke Mander,; Jacklyn Rodriguez,; Pietra G. Mueller,; Jackson, Stephen T.; Surangi W. Punyasena,

    2014-01-01

    Late Quaternary fluvial deposits in the Tunica Hills region of Louisiana and Mississippi are rich in spruce macrofossils of the extinct species Picea critchfieldii, the one recognized plant extinction of the Late Quaternary. However, the morphology of P. critchfieldii pollen is unknown, presenting a barrier to the interpretation of pollen spectra from the last glacial of North America. To address this issue, we undertook a morphometric study of Picea pollen from Tunica Hills. Morphometric data, together with qualitative observations of pollen morphology using Apotome fluorescence microscopy, indicate that Picea pollen from Tunica Hills is morphologically distinct from the pollen of P. glauca, P. mariana and P. rubens. Measurements of grain length, corpus width and corpus height indicate that Picea pollen from Tunica Hills is larger than the pollen of P. mariana and P. rubens, and is slightly larger than P. glauca pollen. We argue that the morphologically distinctive Tunica Hills Picea pollen was probably produced by the extinct spruce species P. critchfieldii. These morphological differences could be used to identify P. critchfieldii in existing and newly collected pollen records, which would refine its paleoecologic and biogeographic history and clarify the nature and timing of its extinction in the Late Quaternary.

  7. Magnetic Mineralogy as Indicator of dry Conditions in Lacustrine Sediments From Santa María del Oro, Nayarit, Central Mexico

    Science.gov (United States)

    Ortega, B.; Vazquez, G.; Rodriguez, A.

    2007-05-01

    Combined magnetic and geochemical analysis were conducted on laminated sediments from Santa Maria del Oro, a crater lake in Nayarit (Mexico), to build up a model of paleoenvironmental conditions for the late Holocene. The occurrence of a severe drought at the end of the archeological Classic period (100 - 900 AD) has been documented in sites of central Mexico (Zirahuen lake and Lerma basin), the Gulf of Mexico coast (Los Tuxtlas) and the Yucatan peninsula. The effects of this climatic event are considered to have stressed the social and political situation in the Yucatan area and other sites in Mesoamerica, and resulted in the "collapse" of the Maya civilization. Santa Maria del Oro sediments between ca. 600 - 1140 AD are characterized by repeated sequences of ocher silt laminae with high inorganic carbon content, authigenic siderite, and low concentration of SD magnetic minerals, followed upward by an increase of concentrations of fine grained SD and SP ferrimagnetic minerals in brown silt laminae. This sequence is considered to represent dissolution-precipitation cycles of magnetic minerals in low erosion, concentrated waters and anoxic water-sediment interface environments. Dissolution of magnetite occurs in reductive conditions, which are considered as warmer and dryer periods. Above the ocher silt, precipitation of fine grained magnetite occurs when conditions change to oxic environments. Ostracode C and O isotopy document a negative precipitation/evaporation balance during this time period.

  8. Reconstructing the pre-Quaternary landscape in Agnew-Lawlers area, Western Australia with emphasis on the Permo-Carboniferous glaciation and post-glacial weathering

    Science.gov (United States)

    Salama, Walid; Anand, Ravi R.

    2017-01-01

    The pre-Quaternary stratigraphic section in Agnew-Lawlers area consists of Permo-Carboniferous glacial sediments, unconformably overlain by Tertiary clastics of palaeochannel sequence and Quaternary alluvial and colluvial sediments. The unique Permo-Carboniferous glacial sedimentary succession in the Yilgarn Craton has not been studied in detail in terms of vertical chemostratigraphic variations, basin and landscape evolution, diagenesis and post-Permian weathering overprints. In Agnew-Lawlers district, continental facies of glacial diamictites, glaciofluvial sandstones and glaciolacustrine rhythmites vary in thickness from 28 m to 181 m and is preserved beneath Cenozoic sediments as relict landforms in highly irregular, asymmetrical and poorly drained basins. The Permo-Carboniferous sediments were mechanically weathered and eroded by glaciers from the surrounding Archaean basement palaeohighs under a cold arid climate. Textural relationships of diamictites indicate that they were derived from proximal and distal source rocks. The denuded palaeotopography of the basement palaeohighs (source rocks) and Permo-Carboniferous sediments were subjected simultaneously to an intensive, post-Permian chemical weathering. The exposed basement rocks were deeply weathered into residual saprolite, whereas the Permo-Carboniferous sediments were differentiated into three chemostratigraphic units. The diamictite and rhythmite of the lower unit are unweathered and preserves the signature of the glacial/interglacial weathering. Mineralogical and geochemical changes dominated in this unit are related mainly to diagenesis at shallow depth (eogenesis) with no significant compaction. The formation of a paragenetic diagenetic sequence of chlorite, ferroan dolomite and pyrite indicates diagenesis has occurred under reducing and alkaline conditions below the permafrost and modern water table. Mineralogical and geochemical changes dominated in the middle unit are linked mainly to eogenetic

  9. 长江三角洲第四纪沉积记录与古环境响应%RECORDS FROM QUATERNARY SEDIMENT AND PALAEO-ENVIRONMENT IN THE YANGTZE RIVER DELTA

    Institute of Scientific and Technical Information of China (English)

    黎兵; 魏子新; 李晓; 何中发; 张开均; 王张华

    2011-01-01

    The SG7 borehole ( 30°57'32"N , 121°52'03"E) is located at Lin-Gang-Xin-Cheng ( means near harbor new town ) in Nanhui district in Shanghai city in southeastern part of the Yangtze River Delta ( YRD) . This borehole has a thickness of 322m which is filled with the whole Quaternary and part of Pliocene strata. In order to distinguish the sediment change in Quaternary strata in the YRD and to figure out its palaeo-environment, the synthetical experiments were carried out , including grain size analyses, magnetic susceptibility measure , geochemical testing,spore and pollen analysis , OSL dating and paleomagnetic dating. The following results are obtained : ( 1 ) there is a large-scale fining sedimentary sequence upwards in Quaternary strata in SG7 ,composed of six fining sub-sequences upwards ,indicating six different evolution phases in this area during Quaternary. ( 2 ) The sediment of the Quaternary strata in the YRD was changed dramatically at 1. 2MaB. P. During 2. 6MaB. P. to 1. 2MaB. P. , the paleao-Yangtze River flowed through Jiangsu province and entered into the Yellow Sea,while the main sediment from a local small drainage basin, situated southwest to the modern YRD, discharged to the Yangtze River estuary, with the major components originated from upper Jurassic tuff. During 1. 2MaB. P., because of palaeo-climate change and neotectonic movements, the palaeo-Yangtze River channel migrated southwards, and flowed through the present estuary area, and entered into the East China Sea. As a result,current Yangtze River Drainage Basin ( YRDB) became the main sediment source and discharged the sediment to the Yangtze River estuary to form the modern YRD. ( 3 ) Since 1. 2MaB. P. , the magnetic susceptibility of the strata showed the periodic variation accompany with the stratigraphic and geochronological sequences ,and its periods could compare with the orbital parameter periods of the Earth. Thus, it's high probably that the palaeo-climate change in the YRDB was

  10. Reconstruction of late Quaternary marine and terrestrial environmental conditions of Northwest Africa and Southeast Australia : a multiple organic proxy study using marine sediments

    NARCIS (Netherlands)

    Alfama Lopes dos Santos, R.

    2012-01-01

    NW Africa and SE Australia are regions which are particularly vulnerable to climate change. In this thesis, organic proxies are used from marine sediment cores to reconstruct past environmental conditions from these areas. In sediments from NW Africa, the UK'37 showed an efficient proxy for sea sur

  11. Geochemistry of buried river sediments from Ghaggar Plains, NW India: Multi-proxy records of variations in provenance, paleoclimate, and paleovegetation patterns in the Late Quaternary

    DEFF Research Database (Denmark)

    Singh, Ajit; Paul, Debajyoti; Sinha, Rajiv;

    2016-01-01

    are overlain by fluvial sediments (~75 ka-recent). Major oxide compositions of the core sediments (n = 35) generally vary between that observed for the modern-day Ghaggar/Sutlej and Yamuna river sand. The isotopic composition (87Sr/86Sr: 0.7365 to 0.7783 and εNd: -14.6 to -19.0) of core sediments (n = 18...... periods can be explained by increasing sediment contribution from LH (high 87Sr/86Sr and low εNd) due to an increase in glacial cover over HH. Whereas relatively less glacial cover over HH during interglacial periods resulted in more erosion and sediment contribution from HH. The down-core Sr-Nd isotopic...

  12. Introduction to Mineralogy

    Science.gov (United States)

    Knittle, Elise

    A course in mineralogy is a rite of passage for most undergraduate Earth sciences majors. As fluency with minerals is so basic for deciphering a range of geologic processes, many Earth scientists can recall long hours in the lab memorizing mineral samples, their chemical formulae and crystal systems, and perhaps staring through a petrographic microscope wondering, what exactly is 2V? In this venerable field with so many classic textbooks, one might ask why another mineralogy text is warranted.Introduction to Mineralogy is organized in a traditional way, with Part I covering the topics of symmetry, crystallography, crystal chemistry and structure, and crystal growth. Part II covers physical properties of minerals and methods for studying mineral structures and chemistry (including optical mineralogy and x-ray diffraction), and Part III presents the systematic mineralogy of all of the mineral groups.

  13. The provenance of Cretaceous to Quaternary sediments in the Tarfaya basin, SW Morocco: Evidence from trace element geochemistry and radiogenic Nd-Sr isotopes

    Science.gov (United States)

    Ali, Sajid; Stattegger, Karl; Garbe-Schönberg, Dieter; Frank, Martin; Kraft, Steffanie; Kuhnt, Wolfgang

    2014-02-01

    We present trace element compositions, rare earth elements (REEs) and radiogenic Nd-Sr isotope analyses of Cretaceous to recent sediments of the Tarfaya basin, SW Morocco, in order to identify tectonic setting, source rocks composition and sediments provenance. The results suggest that the sediments originate from heterogeneous source areas of the Reguibat Shield and the Mauritanides (West African Craton), as well as the western Anti-Atlas, which probably form the basement in this area. For interpreting the analyzed trace element results, we assume that elemental ratios such as La/Sc, Th/Sc, Cr/Th, Th/Co, La/Co and Eu/Eu∗ in the detrital silicate fraction of the sedimentary rocks behaved as a closed system during transport and cementation, which is justified by the consistency of all obtained results. The La/Y-Sc/Cr binary and La-Th-Sc ternary relationships suggest that the Tarfaya basin sediments were deposited in a passive margin setting. The trace element ratios of La/Sc, Th/Sc, Cr/Th and Th/Co indicate a felsic source. Moreover, chondrite-normalized REE patterns with light rare earth elements (LREE) enrichment, a flat heavy rare earth elements (HREE) and negative Eu anomalies can also be attributed to a felsic source for the Tarfaya basin sediments. The Nd isotope model ages (TDM = 2.0-2.2 Ga) of the Early Cretaceous sediments suggest that sediments were derived from the Eburnean terrain (Reguibat Shield). On the other hand, Late Cretaceous to Miocene--Pliocene sediments show younger model ages (TDM = 1.8 Ga, on average) indicating an origin from both the Reguibat Shield and the western Anti-Atlas. In contrast, the southernmost studied Sebkha Aridal section (Oligocene to Miocene-Pliocene) yields older provenance ages (TDM = 2.5-2.6 Ga) indicating that these sediments were dominantly derived from the Archean terrain of the Reguibat Shield.

  14. Paleoclimatic and diagenetic history of the Late Quaternary sediments in a core from the southeastern Arabian Sea: Geochemical and magnetic signals

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Kessarkar, P.M.; Thamban, M.; Patil, S.K.

    and oxygenated bottom waters in the Holocene are responsible for their variation. The core exhibits different stages of diagenesis at different sediment intervals. The occurrence of fine-grained, low-coercivity, ferrimagnetic mineral during glacial periods...

  15. Lithology, mineralogy and geochemical characterizations of sediment-hosted Sr-F deposits in the eastern Neo-Tethyan region - With special reference to evaporation and halokinesis in Tunisia

    Science.gov (United States)

    Dill, H. G.; Nolte, N.; Hansen, B. T.

    2014-04-01

    The Neo-Tethyan basin is known for its sediment-hosted Sr deposits in Spain, Turkey, Cyprus, and the Gulf Region. Sediment-hosted Sr-F deposits with base metals formed in the rim sinks and on top of salt domes resulting from halokinesis of Triassic evaporites near the southern edge of the Mediterranean Sea in Tunisia. These evaporites delivered part of the elements, created a basin-and-swell topography and provided the local and regional unconformities to which many of the mineral deposits are related. Five mineralizing processes, each with characteristic sedimentary ore textures, are related to this subsurface salt movement: (1 + 2) Early- and late-stage replacement ("zebra rocks"), (3) hydraulic fracturing ("fitting breccia" sensuDill and Weber, 2010b), (4) remobilization ("spinifex structures"), and (5) open-space filling ("caves and vein-like deposits"). Basinal brines from Mesozoic aquifers delivered Pb, Zn, Cd, REE, Y, Hg, and Se, while Sr, Cs, Be, Li, Cu and Co have been derived from Cenozoic salinas of the Neo-Tethyan basin. Mixing of Mesozoic and Cenozoic brines between 28 and 19 Ma provoked the emplacement of Sr-F mineralization at temperatures below 200 °C under strong alkaline conditions. Epigenetic polyphase Sr-F deposits bearing base-metals which are closely related to salt domes (Tunisian-Type) may be traced into epigenetic monophase Sr deposits within bioherms (Cyprus-Type) devoid of Pb, Zn and F. Moving eastward, syndiagenetic monophase Sr deposits in biostromes (Gulf-Type) herald the beginning of Sr concentration in Miocene sabkhas of the Neo-Tethys. The current results are based upon field-related sediment petrography and on mineralogical studies, which were supplemented by chemical studies. The present studies bridge the gap between epigenetic carbonate-hosted MVT and syndiagenetic evaporite deposits, both of which developed during the same time span (Neogene) and were hosted by the same environment (near-shore marine marginal facies of the Neo

  16. Provenance and supply of Fe-enriched terrigenous sediments in the western equatorial Pacific and their relation to precipitation variations during the late Quaternary

    NARCIS (Netherlands)

    Wu, J.W.; Liu, Z.; Zhou, nn.

    2013-01-01

    Iron (Fe) deposition in the equatorial Pacific has important implications for the global carbon cycle, while the provenance of Fe supply and its change remain highly debated. Here, we geochemically characterize the provenance of terrigenous sediments deposited on the pathways of the Equatorial Under

  17. Mineralogy and geochemistry of trace metals and REE in volcanic massive sulfide host rocks, stream sediments, stream waters and acid mine drainage from the Lousal mine area (Iberian Pyrite Belt, Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, E. [GeoBioTec - GeoBiosciences, Technologies and Engineering Research Center, Departamento de Geociencias, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)], E-mail: eafsilva@ua.pt; Bobos, I. [Departamento de Geologia, Faculdade de Ciencias da Universidade do Porto, Rua Campo Alegre 687 4169-007 Porto (Portugal); Xavier Matos, J. [Centro de Estudos Geologicos e Mineiros de Beja, Rua Frei Amador Arrais No. 39 r/c, Apartado 104, 7801-902 Beja (Portugal); Patinha, C.; Reis, A.P.; Cardoso Fonseca, E. [GeoBioTec - GeoBiosciences, Technologies and Engineering Research Center, Departamento de Geociencias, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

    2009-03-15

    Acid mine drainage represents a major source of water pollution in the Lousal area. The concentrations of trace metals and the rare earth elements (REE) in the host rocks, stream sediment, surface waters and acid mine drainage (AMD) associated with abandoned mine adits and tailings impoundments were determined, in order to fingerprint their sources and to understand their mobility and water-rock interaction. The results show that the Fe-SO{sub 4}-rich acid waters vary substantially in composition both spatially and seasonally. These waters include very low pH (mostly in the range 1.9-3.0), extreme SO{sub 4} concentrations (4635-20,070 mg L{sup -1}SO{sub 4}{sup 2-}), high metal contents (Fe, Al, Cu, Zn and Mn) and very high REE contents. The trace metal concentrations decrease downstream from the discharge points either due to precipitation of neoformed phases or to dilution. The North-American shale composite (NASC)-normalized patterns corresponding to sediment from one stream (Corona stream) show a flat tendency or are slightly enriched in light-REE (LREE). The NASC-normalized patterns corresponding to acidic mine waters show enrichment in the middle REE (MREE) with respect to the LREE and heavy REE (HREE). Moreover, the REE concentrations in acidic mine waters are 2 or 3 orders of magnitude higher than those of the surface waters. Changes of REE concentrations and variation of Eu anomaly show two spatially distinct patterns: (a) pond and spring waters with higher REE concentrations (ranging from 375 to 2870 {mu}g L{sup -1}), that records conspicuous negative Eu anomaly, and (b) seeps from tailings impoundments corresponding to lower REE concentrations than the first pattern (ranging from 350 to 1139 {mu}g L{sup -1}) with typically negative Eu anomaly. The stream water samples collected from the impacted stream during the spring show a low pH (2.8-3.1) and contain high concentrations of Fe and trace elements (up to 61 mg L{sup -1}). Also, temporal variations of

  18. Paleoclimatic implications of magnetic susceptibility in Late Pliocene-Quaternary sediments from deep drilling core SG-1 in the western Qaidam Basin (NE Tibetan Plateau)

    Science.gov (United States)

    Zhang, Weilin; Appel, Erwin; Fang, Xiaomin; Yan, Maodu; Song, Chunhui; Cao, Liwan

    2012-06-01

    Lake sediments are important archives of paleoclimate change and erosion history. A 938.5 m long core (SG-1) of lacustrine sediments, dated at 2.77 Ma to 0.1 Ma, was obtained from the western Qaidam Basin in the northeastern Tibetan Plateau, consisting of dark grayish mudstone and grayish siltstone, intercalated with salts and fine sandstones in the upper part. Magnetic susceptibility data, combined with detailed rock magnetic properties, were analyzed for revealing the significance of ferro(i)magnetic concentration for past changes of climate and erosion. Mass-specific susceptibility (χ) shows a striking cyclic and long-term variation. Samples with high χ values are dominated by magnetite and maghemite with pseudo-single-domain properties. In contrast, samples with low χ values contain maghemite from single-domain to multidomain and, additionally, a significant fraction of hematite. The driving mechanism of χ variation can be explained by three alternative models: (1) different source regions with alternations of wind and cryoclastic erosion in a wider hinterland (dry-cold climate) and surface runoff erosion from a narrower area (more humid climate) and (2 and 3) low-temperature oxidation, occurring either in the lake sediments (dry climate) or in the catchment area during weathering (more humid climate). Trends of χ match with changes in sedimention rates and are roughly synchronous with the deep-sea δ18O record on a glacial-interglacial timescale. Therefore, the concentration of magnetic minerals in the western Qaidam Basin sediments is likely controlled by both tectonic influence and paleoenvironmental changes but can be best interpreted by alternations and trends of dry-cold and more humid periods due to Asian drying and global cooling.

  19. Regional variations in provenance and abundance of ice-rafted clasts in Arctic Ocean sediments: Implications for the configuration of late Quaternary oceanic and atmospheric circulation in the Arctic

    Science.gov (United States)

    Phillips, R.L.; Grantz, A.

    2001-01-01

    The composition and distribution of ice-rafted glacial erratics in late Quaternary sediments define the major current systems of the Arctic Ocean and identify two distinct continental sources for the erratics. In the southern Amerasia basin up to 70% of the erratics are dolostones and limestones (the Amerasia suite) that originated in the carbonate-rich Paleozoic terranes of the Canadian Arctic Islands. These clasts reached the Arctic Ocean in glaciers and were ice-rafted to the core sites in the clockwise Beaufort Gyre. The concentration of erratics decreases northward by 98% along the trend of the gyre from southeastern Canada basin to Makarov basin. The concentration of erratics then triples across the Makarov basin flank of Lomonosov Ridge and siltstone, sandstone and siliceous clasts become dominant in cores from the ridge and the Eurasia basin (the Eurasia suite). The bedrock source for the siltstone and sandstone clasts is uncertain, but bedrock distribution and the distribution of glaciation in northern Eurasia suggest the Taymyr Peninsula-Kara Sea regions. The pattern of clast distribution in the Arctic Ocean sediments and the sharp northward decrease in concentration of clasts of Canadian Arctic Island provenance in the Amerasia basin support the conclusion that the modem circulation pattern of the Arctic Ocean, with the Beaufort Gyre dominant in the Amerasia basin and the Transpolar drift dominant in the Eurasia basin, has controlled both sea-ice and glacial iceberg drift in the Arctic Ocean during interglacial intervals since at least the late Pleistocene. The abruptness of the change in both clast composition and concentration on the Makarov basin flank of Lomonosov Ridge also suggests that the boundary between the Beaufort Gyre and the Transpolar Drift has been relatively stable during interglacials since that time. Because the Beaufort Gyre is wind-driven our data, in conjunction with the westerly directed orientation of sand dunes that formed during

  20. Quaternary magnetic and oxygen isotope stratigraphy in diatom-rich sediments of the southern Gardar Drift (IODP Site U1304, North Atlantic)

    Science.gov (United States)

    Xuan, Chuang; Channell, James E. T.; Hodell, David A.

    2016-06-01

    The sediment sequence from Integrated Ocean Drilling Program (IODP) Site U1304 (53°03.40‧N, 33°31.78‧W; water depth, 3024 m) on the southern Gardar Drift, North Atlantic Ocean, covers the last ∼1.8 Myr with a mean sedimentation rate of ∼15 cm/kyr. At Site U1304, paleomagnetic directional and relative paleointensity (RPI) records have been generated for the last ∼1.5 Myr, and benthic oxygen isotope data for the last ∼1 Myr. The age model for Site U1304 was established by matching δ18O and RPI data to calibrated reference records. Prominent intervals of diatom mats at Site U1304 are associated with the latter stages of interglacial marine isotope stages (MIS) 9, 11, 13, 15, 21, 27 and 35, and with the weak glacial of MIS 14. The deposition of diatom mats, and associated diluted magnetic mineral concentrations, leads to weak magnetizations and susceptibilities in these intervals. Comparison of histograms of paleomagnetic directions and RPI from diatom-rich sediments and from surrounding silty clays indicates that, although results from diatom-rich sediments are more scattered, the occurrence of diatom mats does not appreciably distort the paleomagnetic directional and RPI records. Site U1304 sediments record the Matuyama/Brunhes boundary (∼772 ka), the Jaramillo Subchron (∼993-1071 ka) and the Cobb Mountain Subchron (∼1193-1219 ka), as well as three apparent geomagnetic excursions in the Matuyama Chron, interpreted as the "Kamikatsura/Santa Rosa", "Punaruu", and "Gardar" excursions, at ∼888 ka, ∼1124 ka, and ∼1463 ka, respectively. The Site U1304 RPI record can be correlated with the PISO-1500 RPI stack and with other high-resolution RPI records from the North Atlantic Ocean. Wavelet analyses performed on the Site U1304 RPI record and a new high-resolution North Atlantic paleointensity stack for the last 1500 kyr (HINAPIS-1500), comprising Ocean Drilling Program (ODP) Sites 983, 984 and IODP Sites U1306 and U1304, did not reveal significant

  1. PROGRESS IN QUATERNARY AEOLIAN ENVIRONMENT RESEARCH

    Institute of Scientific and Technical Information of China (English)

    LU Rui-jie; CHEN Yuan; HASI Eerdun; YUE Xing-ling

    2005-01-01

    Quaternary aeolian environment researches were mainly conducted by analyzing the information carri-ers, extracting valuable evidences about aeolian environment changes, so to presume and reconstruct paleoenviron-ments. This paper formulated progress in Quaternary aeolian environment research using dune-morphological records,sedimentological records and bio-fossils records, as well as advances about chronology; presented that people shouldpay more attention to further synthetic study of multi-types of records including dune morphology, size, formationtime, sediment supply, and their relations with wind regime in future, especially the research on dating method.

  2. Mineralogy in Geotechnical Engineering

    Directory of Open Access Journals (Sweden)

    A. Namdar

    2010-01-01

    Full Text Available The several investigations on soils by different researchers have been executed, but research on soil mechanical propertiesbased on mineralogy is very meager, in this regard the author intention is employee of natural minerals for evaluation of soilcohesion, it may leads to developments of a soil with appropriates characteristics in permeability, transmitting load, resistingagainst deformation and settlement. This paper deals with analysis of soil cohesion based on mineralogy. The result revealedcohesion of a plastic soil could be improve by mineral presented in an non plastic soil, and also carbonate has negative affecton soil cohesion and some other soil minerals also have same affect on cohesion that required to be more investigate.

  3. Evaluation of simple geochemical indicators of aeolian sand provenance: Late Quaternary dune fields of North America revisited

    Science.gov (United States)

    Muhs, Daniel R.

    2017-09-01

    Dune fields of Quaternary age occupy large areas of the world's arid and semiarid regions. Despite this, there has been surprisingly little work done on understanding dune sediment provenance, in part because many techniques are time-consuming, prone to operator error, experimental, highly specialized, expensive, or require sophisticated instrumentation. Provenance of dune sand using K/Rb and K/Ba values in K-feldspar in aeolian sands of the arid and semiarid regions of North America is tested here. Results indicate that K/Rb and K/Ba can distinguish different river sands that are sediment sources for dunes and dune fields themselves have distinctive K/Rb and K/Ba compositions. Over the Basin and Range and Great Plains regions of North America, the hypothesized sediment sources of dune fields are reviewed and assessed using K/Rb and K/Ba values in dune sands and in hypothesized source sediments. In some cases, the origins of dunes assessed in this manner are consistent with previous studies and in others, dune fields are found to have a more complex origin than previously thought. Use of K/Rb and K/Ba for provenance studies is a robust method that is inexpensive, rapid, and highly reproducible. It exploits one of the most common minerals found in dune sand, K-feldspar. The method avoids the problem of using simple concentrations of key elements that may be subject to interpretative bias due to changes in mineralogical maturity of Quaternary dune fields that occur over time.

  4. Meiofauna, microflora and geochemical properties of the late quaternary (Holocene) core sediments in the Gulf of Izmir (Eastern Aegean Sea, Turkey)

    Science.gov (United States)

    Yümün, Zeki Ü.; Meriç, Engin; Avşar, Niyazi; Nazik, Atike; Barut, İpek F.; Yokeş, Baki; Sagular, Enis K.; Yildiz, Ayşegül; Eryilmaz, Mustafa; Kam, Erol; Başsari, Asiye; Sonuvar, Bora; Dinçer, Feyza; Baykal, Kubilay; Kaya, Seyhan

    2016-12-01

    The Gulf of Izmir has seen the construction of marinas at four locations; Karşıyaka, Bayraklı, İnciraltı and Urla (Çeşmealtı). Six drilling holes have been structured for each location. Morphological abnormities observed in foraminifer tests, obtained from these core drillings, and coloring encountered in both foraminifer tests and ostracod carapeces, provide evidence of natural and unnatural environmental pollution. The objectives of this study are to identify micro and macro fauna, foraminifers in particular, contained within sediments in the above-mentioned locations; to investigate the background of pollution in the Gulf Region; and to determine pollution's impact upon benthic foraminifer and ostracods. Çeşmealtı foraminifera tests did not lead to color and morphological changes. But foraminifera tests samples collected from Karşıyaka, Bayraklı and İnciraltı led them to turn black (Plate 4-6). However, concentrations of heavy metals (Ni, Cr and Mn) obtained from the sediments of Karşıyaka, Bayraklı and İnciraltı locations are higher than those obtained from the Çeşmealtı samples and high concentrations of these elements may be the cause of the color change in the samples during the foraminifera tests. In Karşıyaka and Bayraklı ostracod samples, Bosquetina carinella, Pterygocythereis jonesi, Semicytherura species; in the Çeşmealtı/Urla zone, Cyprideis torosa; in İnciraltı, Pseudopsammocythere reniformis; and in four zones, Loxoconcha and Xestoleberis species were observed in the range of relative frequency. The same analyses were done on nannoplankton but they did not lead to color and morphological changes.

  5. Variable scale channel avulsion history using fan architecture and stratigraphy, and sediment provenance of Sutlej-Yamuna fans in northwest Gangetic plains during Late Quaternary

    Science.gov (United States)

    Singh, Ajit; Gupta, Sanjeev; Sinha, Rajiv; Densmore, Alexander; Buylaert, Jan-Pieter; Carter, Andrew; Van-Dijk, Wout M.; Joshi, Suneel; Nayak, Nibedita; Mason, Philippa J.; Kumar, Dewashish; Mondal, Setbandhu; Murray, Andrew; Rai, Shiv P.; Shekhar, Shashank

    2016-04-01

    Channel avulsion during fan development controls distribution and deposition of channel sandbodies and hence alluvial architecture of a fan system. Variable scale spatio-temporal information of fluvial responses to past climate changes is stored in these channel sandbodies. Further these channel sandbodies form fluvial aquifers in alluvial fans and therefore understanding of alluvial architecture and stratigraphy of a fan is crucial for development of groundwater management strategies. In this study we used multiple approaches to map subsurface fluvial aquifer architecture and alluvial stratigraphy, and to estimate sediment provenance using U-Pb dating of detrital zircon grains of Sutlej-Yamuna fan system in northwest India. Satellite imagery based geomorphic mapping shows two large fan system with interfan area. The fan surfaces show presence of major and minor paleochannels. 2D resistivity tomography along several transects across fan surfaces shows distinct layers with contrasting resistivity values. These geo-electric facies corresponds to presence of channel sandbodies beneath surface signature of paleochannels and finer floodplain deposits useful to demarcate lateral extent of subsurface channel sandbodies. A more detailed subsurface stratigraphy using ~50m deep sediment cores and their luminescence ages from across fan surface shows presence of multi-storey sandbodies (MSB) separated by floodplain fines. Within the MSB, individual channel deposits are identified by presence of channel scour surfaces located at coarse sand overlying fine sand layer. Depositional ages of MSB's ranges from ~81 ka (late MIS5) to ~15 ka (MIS2) with major depositional break during MIS3 in parts of the fans. Sediment aggradation rate varies laterally across fan surface as well as vertically down the depth with an average rate of 0.54 mm/year. Fluvial channel persistence for studied time interval (about last 81 ka BP) shows major depositional breaks (and possible incision) at ~41 ka

  6. Age determination and development of experimental methods for quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Kim, Jeong Min; Lee, S. H.; Han, J. H.; Shin, H. S.; Cheong, Y. J. [Korea Basic Science Institute, Daejeon (Korea, Republic of); Lee, H. S. [Pukyong National Univ., Busan (Korea, Republic of); Hong, D. G. [Kangwon National Univ., Gangneung (Korea, Republic of)

    2006-02-15

    Correlation of palaeo-shoreline elevations indicates that the MQt{sub 4} terrace in Suryum site has formed during MIS 5e, which is supported by stratigraphically concordant OSL ages for NQt{sub 3} terrace sediments in Yonghan area. Sedimentological features of the trench site of the Eupcheon fault suggest multiple fault movements during the Late Quaternary. All of these observations imply that uplift rate in the middle part of the coast has been much larger than that in the northern part during 125 ka {approx} 80 ka, requiring the revision of conventional view that the Korean peninsula is tectonically very stable. The ESR data suggest that the Ilkwang fault zone has been formed by the initial surface fault activity at 2-3 Ma and reactivated at least 4 times at 1.2-1.3 Ma, 1 Ma, 0.6 Ma and 0.5 Ma, with part of adjacent NNE and NE trending faults. The Eupcheon fault has been reactivated along the boundary between fault breccia originated from Cretaceous sedimentary rocks and Tertiary lithic tuff at around 2 Ma, 1.3 Ma, and 1 Ma. It has been reactivation again along the boundary between Cretaceous sandstone and fault breccia at 0.8 Ma, and between fault breccia and Tertiary lithic tuff at 0.6 Ma. During the late Quaternary after MIS 5e, the Eupcheon fault reactivated along the boundary between fault gouges, cutting Quaternary marine terrace deposits. The ESR data for the Eupcheon fault, however, should be carefully reexamined because it is probable that the samples contain clay components of weathering, not cataclastic origin. A weathering profile developed in the Suryum site was disturbed by tectonic movement that appears to be a simple one-time reverse faulting event based on field observations. A comparative analysis of the mineralogy, micromorphology, and chemistry of the weathering profile and fault gouge, however, reveals that both the microfissures in the deformed weathering profile and larger void spaces along the fault plane were filled with multi

  7. Paleomagnetism on the Quaternary marine sediment at the DH-1 long-core site in the Korean continental margin of the East Sea

    Science.gov (United States)

    Ryang, Woo Hun; Lee, Byungju

    2014-05-01

    A long core of 23.6 m was acquired in the Korean continental margin of the western East Sea. The core site of the DH-1 is located in the offshore of the Donghae City and the water depth is 357.8 m deep. In this area, the paleomagnetism and magnetostratigraphy were firstly reported using 420 samples collected from the long-core sediments. Based on the inclination distribution of the depositional remanent magnetization, the DH-1 core could be divided into two upper and lower units at the boundary of 1750 cm below seafloor. The upper unit is characterized by a positive polarity, whereas the lower unit by a negative polarity. The boundary of the upper and lower units was interpreted as the Brunhes-Matuyama boundary (778 ka). The chemical components of tephra layer at 2014 cm below seafloor belong to alkaline series, plotted between the tephra components of the Mount Baekdu and Ulleung Island. Key words: magnetostratigraphy, Brunhes-Matuyama boundary, tephra, East Sea Acknowledgements: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0025733) and by the Ministry of Knowledge Economy through the grant of Marine Geology and Geophysical Mapping Project (GP2010-013).

  8. 甘肃玉门地区非海相第四系中的微体化石%MICROFOSSILS IN NON-MARINE QUATERNARY SEDIMENTS FROM YUMEN OF GANSU PROVINCE, CHINA

    Institute of Scientific and Technical Information of China (English)

    勾韵娴; 章炳高

    2013-01-01

    本文对甘肃玉门花海地区中更新世内陆盐湖相沉积物中保存完好的广盐性介形类Eucypris mareotia (Fischer,1855)和广盐性有孔虫Ammonia beccarii(Linné,1758),以及极少量保存很差的钙质超微化石为代表的微体化石群特征进行了简述;对化石群中各门类化石的保存和埋葬状况进行了分析;探讨了有孔虫和钙质超微化石的来源;对非海相沉积物中有孔虫的变异进行了分析和研究.研究结果进一步证实,广盐性有孔虫在远离海洋的内陆盐湖环境中,在适宜的盐度条件下,有生存和繁殖的可能性.%Fifteen nonmarine Quaternary samples are analyzed from the Middle Pleistocene saline-lacustrine deposits of Yumen, Gansu Province. A plentiful valves of Eucypris mareotica (Fisher, 1855) (Ostracoda) associated with a small number of Ammonia beccarii (Linne, 1758) (Foraminifera) are encountered in some of these samples, however sometimes E. mareotica presents alone in another samples. Besides, a few nannofossils are also found in some samples. E. mareotica is a typical salt lake ostracod species, appearing from the Pleistocene to Recent, and it is exactly an euryhaline one. Its saline tolerance ranges from 5‰ to >100‰. A. beccarii, emerging from the Miocene to Recent, is a shallow-water benthic form. It is also an euryhaline species, with the salinity from 0‰ to >90‰. A. beccarii is widely spread in the sea and marine-continental trasitional areas, while it is also found in recent salt lakes and Quter-nary saline-lacustrine sediments in inland basins in China, which are located far from the sea. Both E. mareotica and A. beccarii comprise adults and a large number of juveniles. They are well preserved almost without broken and dissolved specimens. The variation, distinguished from the normal marine forms of A. beccarii, shows in the juveniles. Based on the state of the preservation, the population composition and the special variation in juveniles

  9. Late Quaternary record of pteropod preservation from the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sijinkumar, A.V.; Nath, B.N.; Guptha, M.V.S.

    . Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments. Geochimica et Cosmochimica Acta 73, 6771–6788. Brown, B.E., 2007. Coral reefs... Quaternary millennial-scale variability in pelagic aragonite preservation off Somalia. Marine Micropaleontology 59, 171- 183. Klöcker, R., Henrich, R., 2006. Recent and Late Quaternary pteropod preservation on the Pakistan shelf and continental slope...

  10. Effects of a regional décollement level for gravity tectonics on late Neogene-Quaternary deep-sea clastic sedimentation in the Foz do Amazonas Basin, Brazil

    Science.gov (United States)

    Cruz, A. M.; Gorini, C.

    2015-12-01

    Sets of 2D multi-channel seismic and chronostratigraphic data allowed us to undertake analyses of source to sink processes and triggering mechanisms of the gigantic megaslides previously documented off the NW and SE steep slope settings of the Foz do Amazonas basin. These megaslides comprise two sets of stacked allochthonous masses within the Upper Miocene-Quaternary sedimentary record, now described as Mass-Transport Complexes (MTCs): the Amapá Megaslide Complex (AMC) and the Pará-Maranhão Megaslide Complex (PMMC). Individual megaslides of both MTCs can mobilize to deep waters up to kilometer thick sedimentary series as allochthonous masses with different flow directions, degrees of sediment disruption and internal coherence. Megaslides spread downslope over areas as large as thousands of km2, attaining dimensions comparable to the world's largest mass-transport deposits. The basal and largest megaslide of the AMC (AM1 megaslide) is a quite unique example of mass-transport deposit, since it is interpreted as a dominant carbonate allochthonous mass sourced from a mixed carbonate-siliciclastic platform. According to stratigraphic correlations with global sea-level positions, platform instability would have been triggered between the late Miocene and the end of the Early Pliocene by gravitational collapse of the mixed platform under its own weight, after successive subaerial exposures which were able to generate karstification processes. Siliciclastic-type megaslides, on the other hand, are all sourced from large upslope slide and/or rotated blocks (up to 60 km large in the case of the PMMC).Stratigraphic correlations evidenced that horizon equally acts as the upper décollement level for the gravity tectonic system that operates in the regional scale of the Foz do Amazonas basin. In such a context, results of this work evidence complex links between variable modes of gravity deformation (gravity tectonics and mass wasting), all induced by instability created from

  11. Environmental Mineralogical Materials

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Basic properties, including surface absorption, porous filtration, ion exchange, heat effect and chemical solubility of environmental mineralogical materials, are widely applied to the pollution prevention environment improvement. The pollunian prevenition environmenr means the quality improvement of surface water, groundwater, river, lake and ground reservoir: the improvement of soil, the disposal of nuclear waste, the purification of domestic sewage, the collection of smoke and dust and the treatment of waste water. The prospective investigation and utilization of environmental mineralogical materials have been dealt with in more detail by the author of this paper with emphases on the prevention and control of soil contamination by heavy metals, on the quality im provement and treatment of surface water and groundwater,and on the collection of smoke and dust arising from burning coals.

  12. Sulfide Mineralogy and Geochemistry

    Science.gov (United States)

    Dilles, John

    2007-02-01

    Reviews in Mineralogy and Geochemistry Series, Volume 61 David J. Vaughan, Editor Geochemical Society and Mineralogical Society of America; ISBN 0-939950-73-1 xiii + 714 pp.; 2006; $40. Sulfide minerals as a class represent important minor rock-forming minerals, but they are generally known as the chief sources of many economic metallic ores. In the past two decades, sulfide research has been extended to include important roles in environmental geology of sulfide weathering and resultant acid mine drainage, as well as in geomicrobiology in which bacteria make use of sulfides for metabolic energy sources. In the latter respect, sulfides played an important role in early evolution of life on Earth and in geochemical cycling of elements in the Earth's crust and hydrosphere.

  13. Biostratigraphic and paleoclimatic zoning of upper quaternary sediments from the Campos basin slope, RJ, Brazil; Zoneamento bioestratigrafico e paleoclimatico dos sedimentos do quaternario superior do talude da bacia de Campos, RJ, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Vicalvi, Marco Aurelio [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Setor de Bioestratigrafia e Paleoecologia

    1997-12-01

    Classic methods to analyze the post-Pliocene climatic changes were applied to samples from the Campos Basin. Twenty-six samples were piston cored from the sloping bank, and 1 306 samples were collected from three continuously cored drill holes. A selection was made among planktonic foraminifera indicating warm and cold waters and profiles were plotted and their percentages generated paleoclimatic curves. The comparison of these curves with those by Ericson and Wollin, permitted the identification of several glacial and interglacial intervals, and the age determination of the main climatic events that took place in the Campos Basin slope during the last 145 to 150 thousand years of the Upper Quaternary. Based on the frequency variations of the Globorotalia menardii s.l., Globorotalia inflata and Globorotalia truncatulinoides, complemented with observations on the disappearance/reappearance of the Pulleniatina complex, it was possible to subdivide the Z (Holocene), Y and X (Pleistocene) zones of the long cores (drill holes), into 15 sub zones (Z 1, Z 2, Y 1, Y 2 and X 1 to X 11). With this result it is possible to refine the correlation exercises for the cores and improve the calculations of sedimentation rates for these sections. The piston cores, relatively short, were useful to establish precisely the Pleistocene/Holocene boundary for many areas of the Campos Basin slope, and calibrate the bio-horizon where the Pulleniatina obliquiloculata disappeared. The disappearance of the Pulleniatina complex within the median section of the Y Zone establishes an age of approximately 42 000 years, and the disappearance of the Globorotalia flexuosa within the top portion of X Zone, indicates the end of the last interglacial period (84 000 years). This collection of data, when correlated with Bolli and Premoli Silva's bio stratigraphic zoning, shows that the sampled sediments are located in the upper portion of the Globorotalia truncatulinoides truncatulinoides Zone. The

  14. Clay mineralogy of the mud banks of Cochin

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, R.R.; Murty, P.S.N.

    The mineralogy of the sediments constituting the mud banks formed off Cochin, Kerala, India was studied. The clay mineral composition was used as a means of understanding the nature and source of origin of the muds. Fine fraction of the mud samples...

  15. A case for wind enhanced tectonics: Plio-Quaternary sedimentation, erosion, and structural evolution controlled by wind within the Qaidam Basin, China

    Science.gov (United States)

    Heermance, R. V.; Kapp, P. A.; Pullen, A.; Garzione, C. N.

    2012-12-01

    The interplay between tectonics and localized erosion through fluvial and/or glacial processes has been widely documented. Wind erosion, however, has gone largely un-recognized as a potentially important process in this concept. We document an acceleration in shortening in response to wind deflation above actively deforming fault propagation anticlines since ~3.0 Ma in the Qaidam Basin, China. Evidence for this comes from a 1750 m measured section along the southwestern flank of an intra-basin anticline (38.33°N, 93.46°E) and regional cross-sections. Magnetostratigraphy provides age control for prominent stratigraphic and isotopic changes within the section. A positive shift of ~6‰ in the δ18O values of lake carbonates occurs at 1090 m (3.1 Ma), interpreted to be the result of increased aridity at that time. An intraformational angular unconformity, associated with anticline growth, appears at 1172 m (3.0 Ma) and records the initiation of growth strata deposition. At 1235 m (2.6 Ma), a marked lithofacies change to sub-aerial, evaporitic conditions is observed, and is associated with a 3-fold reduction in sedimentation rate. Paleo-yardangs, which are wind-eroded landforms preserved in the stratigraphic record, appear at 1260 m (2.4 Ma). These observations indicate that regional aridification at 3.1 Ma was followed closely by or coincident with fold growth. Facies changes to more evaporitic strata and erosion of the basin floor (based on paleo-yardangs) trailed initial climate and tectonic changes by 500,000-700,000 years. Although the on-lap relationship of post-growth strata implies that syn-tectonic strata may have pinched-out along the flanks of the anticline, our new analysis indicates that at least 1172 m of pre-growth strata must have been eroded from the core of the anticline since 3.0 Ma at a time-averaged rate of ~0.4 mm/year, comparable to fluvial and glacial erosion rates within active tectonic settings. The lack of an integrated fluvial channel

  16. Quaternary Arctic Climate Change of the past 2.8 Ma as reconstructed from sediments of Lake El'gygytgyn, NE Russia (Invited)

    Science.gov (United States)

    Wennrich, V.; Melles, M.; Brigham-Grette, J.; Minyuk, P.; Nowaczyk, N. R.; Deconto, R. M.; Anderson, P. A.; Andreev, A. A.; Haltia, E.; Kukkonen, M.; Lozhkin, A. V.; Rosen, P.; Tarasov, P. E.

    2013-12-01

    Scientific deep drilling at Lake El'gygtygyn in Chukotka, northeastern Russia (67.5° N, 172° E) revealed the first high-resolution record of environmental history in the Arctic that spans the past 3.6 Ma continuously (Melles et al. 2012, Brigham-Grette et al. 2013). In this presentation we focus on the end-member glacial and interglacial climatic conditions of the past 2.8 Ma as clearly reflected in the pelagic lake sediments recovered. Peak glacial conditions, when mean annual air temperatures at least 3.3 (×0.9) °C lower than today led to perennial lake ice (Nolan 2013), first appeared at Lake El'gygytgyn 2.602 - 2.598 Ma ago, during marine isotope stage (MIS) 104. These pervasive glacial episodes gradually increase in frequency from ~2.3 to ~1.8 Ma, eventually concurring with all glacials and several stadials reflected globally in stacked marine isotope records. Particularly warm interglacials, in contrast, experienced a long ice-free season and enhanced nutrient supply from the catchment, which allowed for significantly higher primary production than today. These settings were most pronounced for MIS 11c, 31, 49, 55, 77, 87, 91, and 93. Their exceptional character becomes evident based upon pollen-based climate reconstructions in selected interglacials, showing that the mean temperature of the warmest month and the annual precipitation during the thermal maxima of MIS 11c and 31 ('super' interglacials) were 4-5 °C and ~300 mm higher than those of MIS 1 and 5e ('normal' interglacials), respectively. According to climate simulations, the exceptional warm and moist climates at least during MIS 11c cannot be explained by the natural variability in Earth's orbital parameters and greenhouse gas concentrations alone. A remarkable coincidence of the super interglacials at Lake El'gygytgyn with diatomite layers in the Antarctic ANDRILL 1B, which reflect periods of a diminished West Antarctic Ice Sheet (WAIS) (Naish et al. 2009, Pollard and DeConto 2009), suggests

  17. QUATERNARY GEOLOGY & GEOMORPHOLOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20112526Bai Daoyuan (Hunan Institute of Geology Survey,Changsha 410011,China); Liu Bo Quaternary Tectonic-Sedimentary Characteristics and Environmental Evolution of Linli Sag,Dongting Basin (Journal of

  18. QUATERNARY GEOLOGY & GEOMORPHOLOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111129 Bai Daoyuan(Hunan Institute of Geological Survey,Changsha 410011,China);Li Chang’an Quaternary Tectonic-Sedimentary Characteristics and Environmental Evolution of Anxiang Sag in Dongting Basin and Its West Periphery(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,32(2),2010,p.120-129,6 illus.,1 table,48 refs.)Key words:Quaternary,sedimentary environment,structural evolution,Dongtinghu Basin Detailed geologic mapping and bore data was conducted to study on the Quaternary tectonic and sedimentary characteristics and environmental evolution of Anxiang Sag and its west periphery of Dongting Basin,which provided new materials for Quaternary geology of Jianghan-Dongting Basin.The sag trends north-south direction and is surrounded by normal faults.The thickness of Quaternary deposits in the sag is commonly 100~220 m with maximun thickness of 300 m,and from lower to upper,the Quaternary strata is composed of Early Pleistocene Huatian Formation and Miluo Formation,Middle Pleistocene Dongtinghu Formation

  19. Cycling of phosphorus and manganese in the Arabian Sea during the Late Quaternary

    NARCIS (Netherlands)

    Scheanu, S.J.

    1999-01-01

    This thesis investigates phosphorus and manganese cycling in the Arabian Sea during the Late Quaternary, using sediment records recovered during the Netherlands Indian Ocean Programme (NIOP) in 1992. The first part is concerned with the reconstruction of Late Quaternary variability in

  20. Cycling of phosphorus and Manganese in the Arabian Sea during the Late Quaternary

    NARCIS (Netherlands)

    Schenau, S.J.

    1999-01-01

    This thesis investigates phosphorus and manganese cycling in the Arabian Sea during the Late Quaternary, using sediment records recovered during the Netherlands Indian Ocean Programme (NIOP) in 1992. The first part is concerned with the reconstruction of Late Quaternary variability in

  1. The Sediment Sequence in the Southern Gulf of California — Distribution, Thickness, Sedimentlogical and Rock Magnetic Properties

    Science.gov (United States)

    Fucugauchi, J. U.; Perez-Cruz, L.

    2008-05-01

    The Gulf of California is a young tectonic ocean basin formed by sea-floor spreading and transform faulting along the Pacific-North America plate boundary. The Gulf of California is an elongated narrow basin oriented almost N- S, and bordered by the Baja California peninsula and mainland Mexico. To the north, it limits with the basins and transform fault of the San Andreas, and in the south with the East Pacific Rise and transform faults of the Rivera and Cocos plates. Here we focus on the sediment sequence in the southern sector at the mouth of the Gulf and the margin and central basins, which constitute a rich archive of the Gulf tectonic opening, plate boundary reorganizations and the paleoclimatic and paleoenvironmental evolution. Marine magnetic anomalies can be traced to approximately 3.6 Ma ago in the area of the mouth of the Gulf. There are relatively few studies of magnetic mineralogy, rock magnetism, magnetostratigraphy and paleomagnetism in these marine sediments. Here we present initial results of a study on the distribution and relative thickness of the sediment sequences in the mouth of the Gulf from geophysical surveys. Relative distribution and thicknes of sediments correlate with the bathymetry and location with respect to spreading center, transform faults and margins of the peninsula and mainland Mexico. Main sediment sources are silicic rocks from the Comondu Formation in the Baja California peninsula and the intrusive and volcanic rocks in Jalisco and Nayarit, including the Puerto Vallarta batholith. Pluvial terrigenous, fine-grained eolian and biogenic sediments are present in the sediment cores with less frequent turbiditic and tephra deposits. Core analyses of rock magnetic properties and mineralogy at few locations are summarized and discussed in terms of sediment sources, transport and deposition processes, diagenesis, paleoceanographic and paleoclimatic evolution during the Late Quaternary.

  2. Journal of Mineralogical and Petrological Sciences

    Science.gov (United States)

    Official journal of Japan Association of Mineralogical Sciences (JAMS), focusing on mineralogical and petrological sciences and their related fields. Journal of Mineralogical and Petrological Sciences (JMPS) is the successor journal to both “Journal of Mineralogy, Petrology and Economic Geology” and “Mineralogical Journal”. Journal of Mineralogical and Petrological Sciences (JMPS) is indexed in the ISI database (Thomson Reuters), the Science Citation Index-Expanded, Current Contents/Physical, Chemical & Earth Sciences, and ISI Alerting Services.

  3. Quaternary Tipping Points in Tropical Northern Australia

    Science.gov (United States)

    Moss, Patrick; Dunbar, Gavin; Croke, Jacky; Katunar, Rosie

    2016-04-01

    Tropical northern Queensland, particularly the volcanic Atherton Tableland, contains some of the most detailed and longest terrestrial palaeoenvironmental archives in Australia and when combined with adjacent marine sediment records provides key insight into potential environmental 'tipping points' for the entire Quaternary period and beyond. This presentation will provide an overview of some of the key tipping points (i.e. significant landscape transformation) that have occurred within the tropical northern Australian region over the Quaternary, as well as discussing potential causes and subsequent impacts of these transformation episodes. These events include the development of the Great Barrier Reef, transition from obliquity to eccentricity dominated glacial-interglacial cycles, the Mid-Brunhes event, the Oxygen Isotope Stage 6 episode, the arrival of people into the region, Last Glacial-Interglacial Transition and European settlement.

  4. Mineralogy and Geochemistry of Upper Maastrichtian-Middle Eocene Clay - Rich Volcano - Sedimentary Units from South-Eastern of Elazıg Basin (Eastern Turkey)

    Science.gov (United States)

    Akkoca, Dicle Bal; Daş, Burhan

    2017-04-01

    Clay-rich Hazar-Maden volcano-sediments were deposited along the southern branch of the Neotethys Ocean margin during Upper Maastrichtian - Middle Eocene times. Mineralogy and geochemistry of Hatunkoy section from the south - easthern of Elazıg were studied by X-ray powder diffraction (XRD), ICP-AES, ICP-MS. The Upper Jurassic - Lower Cretaceous Guleman Ophiolites, Upper Maastrichtian - Middle Eocene Hazar Group, the Middle Eocene Maden Group, Pliocene-Quaternary alluvial deposits are situated in the study area. The Guleman Ophiolites are composed of dunite, harzburgite with podiform chromite, alternating dunite-wherlite, clinopyroxenite banded gabbro, quartz gabbro/diorite or plagiogranite and volcanites. The Hazar Group consists of limestone and interbedded shale and sandstone. The Maden Group has a complex lithology consisting of limestones, red-green clayey limestones, sandstone, agglomerate, tuffs, reddish mudstone and basaltic-andesitic pillow lavas. Mineralogy and geochemistry of Hazar and Maden Group samples are similar in Hatunkoy section. All samples consist of clay minerals (chlorite, illite), calcite, quartz, and feldspar. SiO2, Al2O3, Fe2O3, K2O contents show that samples are convenient with Fe shales and shales. The ratios of Zr/TiO2, Th/Sc, Zr/Sc, Y/Ni-Cr/V, Al/(Al+Fe+Mn) show dominance of neutral-basic volcanism in the area. Rare earth elements (REE) concentrations of samples are normalized to chondrite values and it is determined that low light rare earth elements (LREEs) are enriched in comparison to high rare earth elements (HREEs), and the absence of Eu anomalies shows that our samples are generally neutral-basic in composition. REE of samples were compared with North American shale composite (NASC), European shale (ES) and Post-Archean Australian shale (PAAS). Elements are not in concurrence with these compositions. Key Words:Mineralogy, Geochemistry, Volcano sedimentary Units, Eastern Turkey.

  5. Latest Pannonian and Quaternary evolution at the transition between Eastern Alps and Pannonian Basin: new insights from geophysical, sedimentological and geochronological data

    Science.gov (United States)

    Zámolyi, A.; Salcher, B.; Draganits, E.; Exner, U.; Wagreich, M.; Gier, S.; Fiebig, M.; Lomax, J.; Surányi, G.; Diel, M.; Zámolyi, F.

    2016-08-01

    The transition zone between Eastern Alps and Pannonian Basin is a key area for the investigation of the interplay between regional uplift, local tectonic subsidence and depositional environment. Our study area, the western margin of the Little Hungarian Plain, is characterized by gentle hills, plateaus and depressions, of which several are filled by lakes—including one of Austria's largest and shallowest lakes, Lake Neusiedl. Geological investigation is hampered by the scarcity of outcrops, and thus direct observation of sedimentological or structural features is difficult. Despite a long research history in the area, a consistent landscape evolution model considering all relevant constraints is lacking so far. In this study, we apply multidisciplinary methods to decipher the complex tectonic and fluvial depositional evolution of the region. Local data from shallow-lake drilling and seismic investigation are combined with regional data from industrial seismics and core data to gain new insights into the latest Pannonian (Late Miocene) and Quaternary evolution. Shallow-lake seismic data show the erosionally truncated Pannonian sediments dipping and thickening toward southeast, toward the modern depocenter of the Little Hungarian Plain. Overlying Quaternary fluvial sediments show a very similar thickening trend except for the area on the plateau north of the lake indicating ongoing subsidence in major parts of the basin. Drill cores from locations along the lake seismic lines were analyzed concerning their age, mineralogy and heavy minerals and compared with outcrop samples from the surrounding plains and the plateau to derive indications on sediment provenance. A key observation is the apparent lack of a significant gravel layer on top of the tilted Pannonian sediments beneath Lake Neusiedl. Small-scale faults can be observed in the lake seismic sections along with key sedimentary features. Significant differences of the current elevation of the top Pannonian

  6. Latest Pannonian and Quaternary evolution at the transition between Eastern Alps and Pannonian Basin: new insights from geophysical, sedimentological and geochronological data

    Science.gov (United States)

    Zámolyi, A.; Salcher, B.; Draganits, E.; Exner, U.; Wagreich, M.; Gier, S.; Fiebig, M.; Lomax, J.; Surányi, G.; Diel, M.; Zámolyi, F.

    2017-07-01

    The transition zone between Eastern Alps and Pannonian Basin is a key area for the investigation of the interplay between regional uplift, local tectonic subsidence and depositional environment. Our study area, the western margin of the Little Hungarian Plain, is characterized by gentle hills, plateaus and depressions, of which several are filled by lakes—including one of Austria's largest and shallowest lakes, Lake Neusiedl. Geological investigation is hampered by the scarcity of outcrops, and thus direct observation of sedimentological or structural features is difficult. Despite a long research history in the area, a consistent landscape evolution model considering all relevant constraints is lacking so far. In this study, we apply multidisciplinary methods to decipher the complex tectonic and fluvial depositional evolution of the region. Local data from shallow-lake drilling and seismic investigation are combined with regional data from industrial seismics and core data to gain new insights into the latest Pannonian (Late Miocene) and Quaternary evolution. Shallow-lake seismic data show the erosionally truncated Pannonian sediments dipping and thickening toward southeast, toward the modern depocenter of the Little Hungarian Plain. Overlying Quaternary fluvial sediments show a very similar thickening trend except for the area on the plateau north of the lake indicating ongoing subsidence in major parts of the basin. Drill cores from locations along the lake seismic lines were analyzed concerning their age, mineralogy and heavy minerals and compared with outcrop samples from the surrounding plains and the plateau to derive indications on sediment provenance. A key observation is the apparent lack of a significant gravel layer on top of the tilted Pannonian sediments beneath Lake Neusiedl. Small-scale faults can be observed in the lake seismic sections along with key sedimentary features. Significant differences of the current elevation of the top Pannonian

  7. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  8. Surficial sediments of the continental shelf off Karnataka

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Nair, R.R.

    on the inner shelf. X-ray mineralogy of the silt fraction of the sediments shows the presence of quartz, calcite, aragonite and orthoclase as major minerals. Some of the sedimentary processes effecting the distribution of these sediments are discussed...

  9. High resolution variability in the Quaternary Indian monsoon inferred from records of clastic input and paleo-production recovered during IODP Expedition 355

    Science.gov (United States)

    Hahn, Annette; Lyle, Mitchell; Kulhanek, Denise; Ando, Sergio; Clift, Peter

    2016-04-01

    The sediment cores obtained from the Indus fan at Site U1457 during Expedition 355 of the International Ocean Discovery Program (IODP) contain a ca. 100m spliced section covering the past ca. 1Ma. We aim to make use of this unique long, mostly continuous climate archive to unravel the millennial scale atmospheric and oceanic processes linked to changes in the Indian monsoon climate over the Quaternary glacial-interglacial cycles. Our aim is to fill this gap using fast, cost-efficient methods (Fourier Transform Infrared Spectroscopy [FTIRS] and X-ray Fluorescence [XRF] scanning) which allow us to study this sequence at a millennial scale resolution (2-3cm sampling interval). An important methodological aspect of this study is developing FTIRS as a method for the simultaneous estimation of the sediment total inorganic carbon and organic carbon content by using the specific fingerprint absorption spectra of minerals (e.g. calcite) and organic sediment components. The resulting paleo-production proxies give indications of oceanic circulation patterns and serve as a direct comparison to the XRF scanning data. Initial results show that variability in paleo-production is accompanied by changes in the quantity and composition of clastic input to the site. Phases of increased deposition of terrigenous material are enriched in K, Al, Fe and Si. Both changes in the weathering and erosion focus areas affect the mineralogy and elemental composition of the clastic input as grain size and mineralogical changes are reflected in the ratios of lighter to heavier elements. Furthermore, trace element compositions (Zn, Cu, Mn) give indications of diagenetic processes and contribute to the understanding of the depositional environment. The resulting datasets will lead to a more comprehensive understanding of the interplay of the local atmospheric and oceanic circulation processes over glacial-interglacial cycles; an essential prerequisite for regional predictions of global climate

  10. Uranium-series comminution ages of continental sediments: Case study of a Pleistocene alluvial fan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Victoria E.; DePaolo, Donald J.; Christensen, John N.

    2010-04-30

    Obtaining quantitative information about the timescales associated with sediment transport, storage, and deposition in continental settings is important but challenging. The uranium-series comminution age method potentially provides a universal approach for direct dating of Quaternary detrital sediments, and can also provide estimates of the sediment transport and storage timescales. (The word"comminution" means"to reduce to powder," reflecting the start of the comminution age clock as reduction of lithic parent material below a critical grain size threshold of ~;;50 mu m.) To test the comminution age method as a means to date continental sediments, we applied the method to drill-core samples of the glacially-derived Kings River Fan alluvial deposits in central California. Sediments from the 45 m core have independently-estimated depositional ages of up to ~;;800 ka, based on paleomagnetism and correlations to nearby dated sediments. We characterized sequentially-leached core samples (both bulk sediment and grain size separates) for U, Nd, and Sr isotopes, grain size, surface texture, and mineralogy. In accordance with the comminution age model, where 234U is partially lost from small sediment grains due to alpha recoil, we found that (234U/238U) activity ratios generally decrease with age, depth, and specific surface area, with depletions of up to 9percent relative to radioactive equilibrium. The resulting calculated comminution ages are reasonable, although they do not exactly match age estimates from previous studies and also depend on assumptions about 234U loss rates. The results indicate that the method may be a significant addition to the sparse set of available tools for dating detrital continental sediments, following further refinement. Improving the accuracy of the method requires more advanced models or measurements for both the recoil loss factor fa and weathering effects. We discuss several independent methods for obtaining fa on individual samples

  11. QUATERNARY GEOLOGY & GEOMORPHOLOGY

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>20050939 An Chengbang (Key Lab. of Western Chinese Environment System, Ministry of Education, Lanzhou University, Lanzhou, Gansu 730000, China); Feng Zhaodong Humid Climate During 9-3. 8 KaBP in the Western Part of Chinese Loess Plateau (Marine Geology & Quaternary Geology, ISSN0256-1492, CN37-1117/P, 24 (3), 2004, p. 111-116, 3 illus. , 1 table, 40 refs. , with English abstract)

  12. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  13. Cyanines Bearing Quaternary Azaaromatic Moieties

    OpenAIRE

    Sbliwa, Wanda; Matusiak, Grazyna; Bachowska, Barbara

    2006-01-01

    Selected cyanines bearing quaternary azaaromatic moieties are presented, showing their monomers, dimers and polymers, as well as their possible applications. Cyanines having NLO properties are also briefly described.

  14. Physicochemical Properties, Micromorphology and Clay Mineralogy of Soils Affected by Geological Formations, Geomorphology and Climate

    Directory of Open Access Journals (Sweden)

    A. Bayat

    2017-01-01

    Full Text Available Introduction: Soil genesis and development in arid and semi-arid areas are strongly affected by geological formations and geomorphic surfaces. Various morphological, physical, and geochemical soil properties at different geomorphic positions are usually attributed to different soil forming factors including parent material and climate. Due to variations in climate, geological formations (Quaternary, Neogene and Cretaceous and geomorphology, the aim of the present research was the study of genesis, development, clay mineralogy, and micromorphology of soils affected by climate, geology and geomorphology in Bardsir area, Kerman Province. Materials and Methods: The study area, 25000 ha, starts from Bardsir and extends to Khanesorkh elevations close to Sirjan city. The climate of the area is warm and semi-arid with mean annual temperature and precipitation of 14.9 °C and 199 mm, respectively. Soil moisture and temperature regimes of the area are aridic and mesic due to 1:2500000 map, provided by Soil and Water Research Institute. Moving to west and southwest, soil moisture regime of the area changes to xeric with increasing elevation. Using topography and geology maps (1:100000 together with Google Earth images, geomorphic surfaces and geologic formations of the area were investigated. Mantled pediment (pedons 1, 3, 7, and 8, rock pediment (pedon 2, semi-stable alluvial plain (pedon 6, unstable alluvial plain (pedon 5, piedmont plain (pedons 9 and 11, intermediate surface of alluvial plain and pediment (pedon 4, and old river terrace (pedon 10 are among geomorphic surfaces investigated in the area. Mantled pediment is composed of young Quaternary sediments and Cretaceous marls. Rock pediments are mainly formed by Cretaceous marls. Quaternary formations are dominant in alluvial plains. Alluvial terraces and intermediate surface of alluvial plain and pediment are dominated by Neogene conglomerates. Siltstone, sandstone, and Neogene marls together with

  15. A mineralogical and geochemical investigation of street sediment near a coal-fired power plant in Hamilton, Ohio: an example of complex pollution and cause for community health concerns.

    Science.gov (United States)

    LeGalley, Erin; Krekeler, Mark P S

    2013-05-01

    The Hamilton Municipal Electric Plant is a 125 MW coal-fired power plant, owned and operated by the City of Hamilton in Butler County, Ohio. The plant is located within 110 m of 50 homes. Bulk chemical investigation of street sediment near these homes indicates average concentrations of 25 ppm Cr, 40 ppm Cu, 15 ppm Ni, 215 ppm Pb, and 500 ppm Zn. Lead and Zn have maximum concentrations of 1207 ppm and 1512 ppm, respectively. Scanning electron microscopy indicates coal ash spherules are present in the street sediment as well as a variety of Pb, Ni, Cr, W, and BaSO4 particulates. Transmission electron microscopy indicates heavy metals are sorbed onto clay particles with some preference for illite over chlorite. This investigation shows bulk chemistry and electron microscopy approaches are very effective tools to investigate particulate pollutants and identify contexts in complex urban settings involving coal pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Mineralogical Results from the Mars Science Laboratory Rover Curiosity

    Science.gov (United States)

    Blake, David Frederick.

    2017-01-01

    NASA's CheMin instrument, the first X-ray Diffractometer flown in space, has been operating on Mars for nearly five years. CheMin was first to establish the quantitative mineralogy of the Mars global soil (1). The instrument was next used to determine the mineralogy of a 3.7 billion year old lacustrine mudstone, a result that, together with findings from other instruments on the MSL Curiosity rover, documented the first habitable environment found on another planet (2). The mineralogy of this mudstone from an ancient playa lake was also used to derive the maximum concentration of CO2 in the early Mars atmosphere, a surprisingly low value that calls into question the current theory that CO2 greenhouse warming was responsible for the warm and wet environment of early Mars. CheMin later identified the mineral tridymite, indicative of silica-rich volcanism, in mudstones of the Murray formation on Mt. Sharp. This discovery challenges the paradigm of Mars as a basaltic planet and ushers in a new chapter of comparative terrestrial planetology (3). CheMin is now being used to systematically sample the sedimentary layers that comprise the lower strata of Mt. Sharp, a 5,000 meter sequence of sedimentary rock laid down in what was once a crater lake, characterizing isochemical sediments that through their changing mineralogy, document the oxidation and drying out of the Mars in early Hesperian time.

  17. Clay minerals as palaeomonsoon proxies: Evaluation and relevance to the late Quaternary records from SE Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Thamban, M.; Rao, V.P.

    as palaeoclimatic proxies are evaluated and discussed. Systematic investigations using several sediment cores from the SE Arabian Sea reveal that despite the influence of several complicating factors, variations in clay mineral composition during the late Quaternary...

  18. Clay Mineralogy of AN Alluvial Aquifer in a Mountainous, Semiarid Terrain, AN Example from Rifle, Colorado

    Science.gov (United States)

    Elliott, W. C.; Lim, D.; Zaunbrecher, L. K.; Pickering, R. A.; Williams, K. H.; Navarre-Sitchler, A.; Long, P. E.; Noel, V.; Bargar, J.; Qafoku, N. P.

    2015-12-01

    Alluvial sediments deposited along the Colorado River corridor in the semi-arid regions of central to western Colorado can be important hosts for legacy contamination including U, V, As and Se. These alluvial sediments host aquifers which are thought to provide important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface. Relatively little is known about the clay mineralogy of these alluvial aquifers and the parent alluvial sediments in spite of the fact that they commonly include lenses of silt-clay materials. These lenses are typically more reduced than coarser grained materials, but zones of reduced and more oxidized materials are present in these alluvial aquifer sediments. The clay mineralogy of the non-reduced parent alluvial sediments of the alluvial aquifer located in Rifle, CO (USA) is composed of chlorite, smectite, illite, kaolinite and quartz. The clay mineralogy of non-reduced fine-grained materials at Rifle are composed of the same suite of minerals found in the sediments plus a vermiculite-smectite intergrade that occurs near the bottom of the aquifer near the top of the Wasatch Formation. The clay mineral assemblages of the system reflect the mineralogically immature character of the source sediments. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate and suggestive of minimal transport of the alluvial sediments from their source areas. Chlorite, smectite, smectite-vermiculite intergrade, and illite are the likely phases involved in the sorption of organic carbon and related microbial redox transformations of metals in these sediments. Both the occurrence and abundance of chlorite, smectite-vermiculite, illite and smectite can therefore exert an important control on the contaminant fluxes and are important determinants of biogeofacies in mountainous, semiarid terrains.

  19. Late Quaternary Environmental Changes Inferred from the stable Oxygen Isotope Composition of Aquatic Insects (Chironomidae: Diptera) and Stable Hydrogen Isotope Composition of bulk sediments from Idavain Lake, Southwest Alaska

    Science.gov (United States)

    Wang, Y.; Finney, B.; Wooller, M. J.

    2007-12-01

    Several techniques are available to examine the isotopic composition of historic lake waters, providing data that can subsequently be used to examine environmental changes. Recently-developed techniques are the stable oxygen isotope analysis of subfossil chironomid (Diptera: Chironomidae) head capsules (mostly chitin) preserved in lake sediments and stable hydrogen isotope analyses directly on bulk sediments. An advantage of using δ18O of chironomids is that the chitinous chironomid headcapsules preserve well in lake sediments, retaining the stable oxygen isotope signature of the lake in which they lived. An advantage of δD analyses of bulk sediments is that a sediment core can be analyzed relatively easily and when the %C (total organic carbon) and %H profiles correlate the data can be used to infer past δD changes of the organics in the sediments. We present results from these analyses of a lake sediment core from Idavain Lake (58°46'N, 155°57'W, 223m above sea level) in southwest Alaska in concert with other paleolimnological proxies, including δ15N, δ13C, LOI, magnetic susceptibility, organic content and opal concentrations for a better understanding of paleolimnological changes since deglaciation for the region. Our preliminilary result shows that downcore shifts of δ18O analyzed from chironomid head capsules coincide well with LOI and pollen changes. The δD of sediments and TOM showed large magnitude changes and reflected the relative lake level changes during the record. This study aim to test the correlation between stable isotope analyese on chiornomid head capsules, lake water, and bulk sediments. In the addition, our study will add to the relatively small database of paleoenvironmental reconstructions from terrestrial sites in Southwest Alaska.

  20. Mineralogia e química dos sedimentos de fundo do médio e baixo Madeira e de seus principais tributários: Amazonas - Brasil Mineralogy and chemistry of bottom sediments of the middle and lower Madeira River and its main tributaries: Amazonas - Brazil

    Directory of Open Access Journals (Sweden)

    Maria Mireide Andrade Queiroz

    2011-01-01

    Full Text Available O objetivo deste trabalho foi investigar a variação composicional e mineralógica dos sedimentos de fundo transportados pelos grandes rios da Amazônia, com nascentes nos Andes provenientes de rochas cratônicas. O estudo foi realizado com base em análises granulométricas, mineralógicas e químicas, incluindo isótopos de Pb, no rio Madeira e seus tributários. O conjunto de dados mostra que os sedimentos de fundo do rio Madeira são granulométrica, mineralógica e quimicamente distintos de seus principais tributários. Os sedimentos do rio Madeira são mais arenosos; têm maior quantidade de quartzo; menor conteúdo de Al2O3, Fe2O3, K2O, MgO, Na2O, PF, TiO2, P2O5, MnO e elementos-traço; e a maturidade aumenta de montante para jusante. Dentre os sedimentos dos tributários, os rios Machado e secundariamente o rio Marmelos são os que mais se aproximam da composição dos sedimentos do rio Madeira, enquanto que o Jamari com sedimentos com maior proporção de TiO2, Zr, Y, Nb, Ga, Hf, U, Ta e ETR, é o mais distinto. Apesar do ambiente de intenso intemperismo e erosão, em condições tropicais úmidas, a que estão submetidas as rochas drenadas pela bacia do rio Madeira, os valores das razões Th/Co, Th/Pb, Th/Yb, Al/Pb, Zr/Co e a composição isotópica de Pb indicam fontes distintas para os sedimentos de fundo estudados. Os sedimentos do rio Madeira são provenientes, principalmente, de rochas máficas, enquanto que os sedimentos de seus tributários têm como fonte essencialmente rochas félsicas.This study reports the granulometric, mineralogic and chemical analyses, including Pb isotope, carried out on the bottom sediments of the Madeira River, whose headwaters are in the Andes Mountain, and its tributaries that come from the cratonic region, in order to investigate the compositional variation of the sediments transported by the major rivers of the Amazon. The analytical data show that the bottom sediments of the Madeira River have

  1. Clay mineral records of East Asian monsoon evolution during late Quaternary in the southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Zhifei; C. Colin; A. Trentesaux; D. Blamart

    2005-01-01

    High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 190 ka during late Quaternary from core MD01-2393 off the Mekong River in the southern South China Sea are reported to reconstruct a history of East Asian monsoon evolution.The dominating clay mineral components indicate a strong glacial-interglacial cyclicity, with high glacial illite, chlorite, and kaolinite contents and high interglacial smectites content. The provenance analysis indicates the direct input of clay minerals via the Mekong River drainage basin.Illite and chlorite derived mainly from the upper reach of the Mekong River, where physical erosion of meta-sedimentary rocks is dominant. Kaolinite derived mainly from active erosion of inhered clays from reworked sediments in the middle reaches. Smectites originated mainly through bisiallitic soils in the middle to lower reaches of the Mekong River. The smectites/(illite+chlorite)and smectites/kaolinite ratios are determined as mineralogical indicators of East Asian monsoon variations. Relatively high ratios occur during interglacials and indicate strengthened summer-monsoon rainfall and weakened winter-monsoon winds; relatively lower ratios happened in glacials, indicating intensified winter monsoon and weakened summer monsoon. The evolution of the summer and winter monsoons provides an almost linear response to the summer insolation of the Northern Hemisphere, implying an astronomical forcing of the East Asian monsoon evolution.

  2. Geomorphology and Quaternary geology of the Dakhla Oasis Region, Egypt

    Science.gov (United States)

    Brookes, Ian A.

    Dakhla Oasis (25.5°N, 29°E) occupies a structurally localized depression at 90-140 m above sea level, ˜1200 km 2 in area, below a 300 m escarpment bordering the Libyan Plateau, Western Desert of Egypt. Semi-arid intervals of the Quaternary period generated eight sedimentary formations, separated by erosion during hyper-arid intervals. Sediments comprise three generations of colluvial/fluvial fanglomerates, two generations of tabular spring-laid clastic and chemical sediments, two generations of mound springs and basinal sediments. of fluvio-lacustrine, evaporitic, pluvio-aeolian and aeolian origins. Discussion of these sediments is organized according to geomorphic region, from north to south, plateau, scarp and piedmont, lowland and cuesta plain. Chronological evidence is restricted to many radiocarbon dates of Holocene cultural material associated with playa sediments (9-4.5 ka), a {Th}/{U} isochron age of ˜62.0 ±7.6 ka for basinal evaporites, and two {Th}/{U} ages of ˜176 and ˜170 ka for a boulder of derived travertine. The regional Quaternary sequence is reconstructed from stratigraphic and geomorphic relationships of the sediments and erosion surfaces. It is broadly similar to sequences earlier reconstructed in the topographically similar Kharga Oasis region 150 km to the east, and Kurkur Oasis, 400 km to the south-southeast. Speculations on chronology and driving mechanism are offered in conclusion.

  3. Occurrence of volcanic ash in the Quaternary alluvial deposits, lower Narmada basin, western India

    Indian Academy of Sciences (India)

    Rachna Raj

    2008-02-01

    This communication reports the occurrence of an ash layer intercalated within the late Quaternary alluvial succession of the Madhumati River, a tributary of the lower Narmada River. Petrographic, morphological and chemical details of glass shards and pumice fragments have formed the basis of this study. The ash has been correlated with the Youngest Toba Tuff. The finding of ash layer interbedded in Quaternary alluvial sequences of western Indian continental margin is significant, as ash being datable material, a near precise time-controlled stratigraphy can be interpreted for the Quaternary sediments of western India. The distant volcanic source of this ash requires a fresh re-assessment of ash volume and palaeoclimatic interpretations.

  4. Verdine and glaucony facies from surficial sediments of the eastern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Thamban, M.; Lamboy, M.

    The present paper reports the first mineralogical description of green grains (verdine and glaucony) from sediments of the eastern continental margin of India. Only 24 of the 82 sediment samples studied, at depths between 18 and 247 m, contain green...

  5. Ground Truth Mineralogy vs. Orbital Observations at the Bagnold Dune Field

    Science.gov (United States)

    Achilles, C. N.; Downs, R. T.; Ming, D. W.; Rampe, E. B.; Morris, R. V.; Treiman, A. H.; Morrison, S. M.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.

    2017-01-01

    The Mars Science Laboratory (MSL) rover, Curiosity, is analyzing rock and sediments in Gale crater to provide in situ sedimentological, geochemical, and mineralogical assessments of the crater's geologic history. Curiosity's recent traverse through an active, basaltic eolian deposit, informally named the Bagnold Dunes, provided the opportunity for a multi-instrument investigation of the dune field.

  6. Size, surface texture, chemical composition and mineralogy interrelations in ferromanganese nodules of central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Pattan, J.N.; Jauhari, P.

    Fiftyseven ferromanganese nodules, classified into 3 size class (4,4-6 and 6-8 cm diam.), from the siliceous sediments of central Indian Ocean were analysed for transition metals and representative sample from each size class for mineralogy. Smaller...

  7. Uplift history of a Betic fold nappe inferred from Neogene-Quaternary sedimentation and tectonics (in the Sierra Alhamilla and Almeria, Sorbas and Tabernas Basins of the Betic Cordilleras, SE Spain)

    NARCIS (Netherlands)

    Weijermars, R.; Roep, Th.B.; Eeckhout, B. van den; Postma, G.; Kleverlaan, K.

    2007-01-01

    Structural, stratigraphical and sedimentological studies of the Alhamilla region show that the Sierra Alhamilla was elevated relative to the surrounding basins by open folding towards the end of the Tortonian period (about 7 Ma ago) and before the onset of Messinian sedimentation. The main arguments

  8. SG06, a fully continuous and varved sediment core from Lake Suigetsu, Japan: stratigraphy and potential for improving the radiocarbon calibration model and understanding of late Quaternary climate changes

    Science.gov (United States)

    Nakagawa, Takeshi; Gotanda, Katsuya; Haraguchi, Tsuyoshi; Danhara, Toru; Yonenobu, Hitoshi; Brauer, Achim; Yokoyama, Yusuke; Tada, Ryuji; Takemura, Keiji; Staff, Richard A.; Payne, Rebecca; Bronk Ramsey, Christopher; Bryant, Charlotte; Brock, Fiona; Schlolaut, Gordon; Marshall, Michael; Tarasov, Pavel; Lamb, Henry; Suigetsu 2006 Project Members

    2012-03-01

    The high potential of the varved sediments of Lake Suigetsu, central Japan, to provide a purely terrestrial radiocarbon calibration model and a chronology of palaeoclimatic changes has been widely recognised for the last two decades. However, this potential has not been fully realised since the only available long sediment core from the lake ('SG93') was extracted from a single bore hole and was therefore interrupted by gaps of unknown duration between successive core sections. In the summer of 2006, a new sediment core ('SG06') was recovered from the lake. Four separate boreholes were drilled and the parallel sets of cores recovered were found to overlap completely, without gaps between segments. This new record provides the ability to test existing atmospheric radiocarbon calibration models, as well as to assess the scale of inter-regional leads and lags in palaeoclimatic changes over the last Glacial-Interglacial cycle. Multi-disciplinary analyses from SG06 are still ongoing, but a reliable description of the sedimentary sequence needs to be provided to the wider science community before major outputs from the project are released, thereby allowing fully-informed critical evaluation of all subsequent releases of data based on the SG06 record. In this paper, we report key litho-stratigraphic information concerning the SG06 sediment core, highlighting changes in the clarity of annual laminations (varves) with depth, and possible implications for the mechanism of the climate change. We also discuss the potential of the SG06 record to meet the fundamental goals of the INQUA-INTIMATE project.

  9. A Quaternary Geomagnetic Instability Time Scale

    Science.gov (United States)

    Singer, B. S.

    2013-12-01

    Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states recorded by lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which O isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments yields a GITS comprising 10 polarity reversals and 27 excursions during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Guass-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron; 19 have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought

  10. Quartz grains SEM surface microtextures of Quaternary glacial sediments along the Diancang Mountain in Yunnan,Southwest China%云南大理点苍山末次冰期冰碛物石英砂扫描电镜形态特征分析

    Institute of Scientific and Technical Information of China (English)

    陈安东; 顾佳妮; 赵志中; 钱方; 王海雷

    2016-01-01

    Diancang Mountain is the place where the concept of Dali Glaciation was put forward,and it is synon-ymous with the Last Glaciation in China. In this study,we applied Scanning Electron Microscopy(SEM)to the samples of Quaternary glacial sediments from the Diancang Mountain. According to the SEM analysis,the main surface microtextures of quartz grains from the Quaternary glacial sediments in Diancang Mountain are as fol-lows:the quartz grains are mainly subangular and sharp angular outline,subedge ridge,high relief in shape;mechanical characters are mainly conchoidal fractures,parallel cleavages,crevasses,adhering particles,stria-tions,V-shaped percussion cracks;chemical features are dissolution pits and grooves,honeycombed solution surface,SiO2 precipitates and silicon film. The features most related to glacial genesis are striations,with its fre-quency of 8%- 32%;adhering particles,with its frequency of 16%- 40%;cracks with its frequency of 12%-32%. According to the SEM of glacial sediments of Diancang Mountain,we obtained the microtextures and its frequency of maritime cirque glacier and hanging glacier. The quartz grains of the glacial sediments are characterized by original features,and glacial mechanical microtextures are not well developed.%云南大理点苍山是大理冰期的命名地,保存有确切的末次冰期冰川作用遗迹。对点苍山冰碛物石英砂进行了扫描电镜形态特征分析,获得了其石英砂形态特征及其频率,并在冰川成因的典型特征的频率上取得了新的认识。扫描电镜分析表明,点苍山冰碛物石英砂形态特征主要为:石英砂形状主要为次棱角状、尖棱角状和多棱角状,边缘多可见次棱脊和棱脊磨损,表面起伏度高;机械特征主要有贝壳状断口、平行解理面、裂隙、粘附碎片、擦痕、机械V形坑;化学特征主要有蚀坑和蚀缝、蜂窝状溶蚀表面、无定形硅沉淀和硅质薄膜。在石英砂表面

  11. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110079 Ding Kuiying(Weifang Entry-Exit Inspection and Quarantine Bureau of the People’s Republic of China,Weifang 261041,China);Zhu Maoxu The Effect of Low Molecular Weight Organic Acids to Phosphate Adsorption by Hydroxyaluminum/Iron-Montmorillonite Complexes(Acta Mineralogica Sinica,ISSN1000-4734,CN52-1045/P,30(1),2010,p.56-62,4 illus.,3 tables,13 refs.)Key words:organic acids,montmorillonit

  12. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20090867 Chen Quanli(Gemmological Institute, China University of Geosciences, Wuhan 430074,China);Qi Lijian Thermal Property of the Apatite Pseudomorphic Turquoise(Earth Science,ISSN1000-2383, CN42-1233/P,33(3),2008,p.416-422, 6 illus.,1 table,11 refs.)

  13. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20090143 Cao Ke (Research Center for Tibeten Plateau Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China); Li Xianghui Cretaceous Clay Minerals and Paleoclimate in Sichuan Basin (Acta Geologica Sinica, ISSN0001-5717, CN11-1951, 82(1), 2008, p.115-123, 3 illus., 3 tables, 30 refs., with English abstract)

  14. MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20150124Ji Liming(Key Laboratory of Petroleum Resources Research of Gansu Province,Lanzhou 730000,China);Ma Xiangxian Relationship between Methane Adsorption Capacity of Clay Minerals and Micropore Volume(Natural Gas Geoscience,ISSN1672-1926,CN62-1177/TE,25(2),2014,p.141-152,7illus.,4tables,21refs.)Key words:clay minerals The pore size,surface area and methane adsorption isotherm of clay-rich rocks are measured.Clay minerals mainly contain micropore of 3~100nm,and have two main in-

  15. Provenance of a prominent sediment drift on the northern slope of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    SHAO; Lei

    2001-01-01

    [1]Sarnthein, M., Pflaumann, U., Wang, P. X. et al., Preliminary report on Sonne-95 cruise “Monitor Monsoon“ to the South China Sea, Reports, Geol.-Palaont. Inst. Univ. Kiel, 68, 1994, 125.[2]Wang, L., Sarnthein, M., High-reso1ution paleoceanographic records during the last 4000 years from the northern slope of the South China Sea, Quaternary Sciences, 1999, 1:27-31.[3]Wang, P.X., Prell, W. L., Blum, P. et al., Proceedings of the Ocean Drilling Program, Initial Reports South China Sea,Volume 184, College Station TX (Ocean Drilling Program), 2000, 18-20.[4]Shao, L., Dong, W., Liu, Z. et al., Trace elements analysis of sediments from the South China Sea, Journal of Tong ji Uni versity, 1999, 27(supp.): 55-60.[5]Taylor, S. R., McLennan, S. M., The Continental Crust: Its Composition and Evolution, in An Examination of the Geo chemical Record Preserved in Sedimentary Rocks, Oxford: Blackwell Scientific Publication, 1985, 1-301.[6]McLennan, S. M., Rare earth elements in sedimentary rocks, Influence of provenance and sedimentary processes, in Geo chemistry and Mineralogy of Rare Earth Elements (ed. Lipin, B. R. et al.), Washington: The Mineralogical Society of America, 1989, 169-200.[7]McLennan, S. M., Hemming, S., McDaniel, M. J. et al., Geochemical approaches to sedimentation, provenance and tec tonics, in Processes Controlling the Composition of Clastic Sediments (ed. Jonhanson, M. J. et al.), Boulder: Geological Society of America, Special Paper 284, 1993, 21-40.[8]Rollinson, H. R., Using Geochemical Data: Evaluation, Presentation, Interpretation, London: Longman Scientific, Tech nical, 1993, 352.[9]Cullers, R. L., Basu, A., Suttner, L. J., Geochemical signature of provenance in sand-mixed material in soils and stream sediments near the Tobacco Root batholith, Montana, USA, Chem. Geol., 1988, 70: 335-348.[10]Bhatia, M. R., Crook, K. A. W., Trace element characteristics of graywackes and tectonic setting discrimination of

  16. Nature and distribution of manganese nodules from three sediment domains of the Central Indian Basin, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Mukhopadhyay, R.

    Manganese nodules from the Central Indian Basin (5 degrees-10 degrees S) vary in abundance, morphology, mineralogy, and chemistry with water depth and sediment type. Nodules from the southern region, dominatEd. by siliceous sediment, differ markedly...

  17. Evidence of seismites in coastal Quaternary deposits of western Oranie (northwestern Algeria)

    Science.gov (United States)

    Boukhedimi, Mohamed Amine; Louni-Hacini, Amina; Bouhadad, Youcef; Ritz, Jean-François; Machane, Djamel; Benhamouche, Azzeddine; Bourenane, Hamid

    2016-10-01

    Coastal Quaternary deposits of western Oranie show typical soft-sediment deformations including sedimentary dykes, sand volcanoes, sismoslumps, thixotropic bowls, thixotropic wedges, diapir-like structures, and faults grading. Field observations indicate that these deformations exist at several levels of the studied deposits along the west Oranian coast. This study demonstrated that these structures are earthquakes-related, by analysis of potential trigger sources. Several arguments demonstrate the seismic origin: the depositional environment rich in water that located in an active tectonic region, the thixotropic nature of deformations and their large vertical and horizontal diffusion in the Quaternary series consistent with a seismic recurrence. This allows characterizing these Quaternary soft-sediment deformations as seismites that were triggered by earthquakes.

  18. 西北冰洋阿尔法脊晚第四纪的陆源沉积物记录及其古环境意义%Late Quaternary Terrigenous Sedimentation in the Western Arctic Ocean as Exemplified by a Sedimentary Record from the Alpha Ridge

    Institute of Scientific and Technical Information of China (English)

    刘伟男; 王汝建; 陈建芳; 程振波; 陈志华; 孙烨忱

    2012-01-01

    通过西北冰洋阿尔法脊B84A孔中—晚第四纪以来的沉积物颜色旋回,Mn、Ca元素相对含量、颜色反射率、有孔虫丰度、冰筏碎屑(IRD)含量、粒度组分及其敏感性分析的综合研究,建立了B84A孔的地层年代框架,其沉积物被划分为MIS 12~MIS 1的沉积序列。阿尔法脊B84A孔可以识别出12个IRD事件,它们大多出现在冰消期,并认为其源区为加拿大北极群岛地区。这些IRD事件反映了加拿大北极冰盖的崩塌和气候变化。阿尔法脊B84A孔沉积物的环境敏感组分分别为细组分(4~9μm)和粗组分(19~53μm),两者的变化趋势相反,主要由海冰和洋流进行搬运,指示了洋流的强度变化。B84A孔的平均沉积速率约为0.4 cm/ka,与阿尔法脊周围地区沉积速率相近。相比于近岸的高沉积速率,其限制因素主要为大面积海冰覆盖造成的较低的生产力和由于长距离搬运造成的较低的陆源输入量。%Terrigenous components in sediment core B84A from the Alpha Ridge,western Arctic Ocean,have been investigated to reconstruct the Mid to Late Quaternary variations in sedimentation,source regions,and related climate changes.The core stratigraphy,evaluated by a combination of variations in Mn content,color cycles,foraminiferal abundance,and lithological correlation,extends back to estimated Marine Isotope Stage(MIS) 12.Twelve ice rafted detritus(IRD,〉250 μm) events were identified and interpreted to mostly occur during the deglacial periods.The Canadian Arctic covered by ice sheets during glacial periods is suggested to be the major source region.The IRD events likely indicate the collapses of ice sheets,possibly in relation to abrupt climate changes.Grain size analysis of B84A indicates sedimentologically sensitive components in core B84A in the silt subfractions 4~9 μm and 19~53 μm,which are inferred to be mainly transported by currents and sea ice

  19. Systematic paleontology of Quaternary ostracode assemblages from the Gulf of Alaska; Part 3, Family Cytheruridae

    Science.gov (United States)

    Brouwers, E.M.

    1994-01-01

    Forty-six species of podocopid ostracodes, most belonging to the Family Cytheruridae, are reported from Quaternary continental-shelf sediments of the Gulf of Alaska. Descriptions and illustrations are provided for 27 new species, 11 previously described species, and 8 species retained in open nomenclature. This report is based on 198 bottom grab samples collected during 1975, 1979, and 1980.

  20. Mineralogy of Selected Paddy Soils in Southeastern China

    Institute of Scientific and Technical Information of China (English)

    F.L.WANG; P.M.HUANG

    1997-01-01

    Limited information is available concerning the mineralogy of paddy soils in the southeastern China, Using chemical methods in conjunction with X-ray diffractometry,we studied the mineral composition of three paddy soils:Jinghua (paddy soil on Quaternary red clay),Fuyang (Hapl-percogenic loamy paddy soil),and Shaoxing(gleyic clayey paddy soil).All the soils contained quartz,mica,vermiculite,chlorite and kaolinite ,and the distribution of these minerals varied with soil prticle size fractions.The clay fraction of the Fuyang and Shaoxing soils aso contained smectite.Although X-ray data did not show the presence of smectite in the Jinghua soil,this mineral was identified by the chemical method.suggesting a transitional property of the mineral in the soil.Hydroxy-Al interlayered minerals were also present in the clay fraction.The amount of smectite in the soils was 31.6(Shaoxing),16.5(Fuyang),and 21.4(Jinghua)g kg-1;for vermiculite it was 33.3(Shaoxing),16.5(Fuyang),and 8.5(Jinghua) g kg-1,Smectite was only Found in the clay fraction,In contrast,amounts of vermiculite in soil particle size fractions were 3.0-11.4(sand), 2.1-6.0(coarse silt),4.6-18.9(medium silt),0.9-40.0(fine silt),and 17.0-108(clay)g kg-1,The amount of noncrystalline aluminosilicates in the soils in g kg-1 decreased in the order:Shaoxing(2.4)>Jinghua (1.9)>Fuyang(1.7).This study has provided useful mineralogical information that is fundamental in future development of management strategies of soils.

  1. Proposal to redefine the Quaternary

    Institute of Scientific and Technical Information of China (English)

    BradPillans

    2004-01-01

    The following proposal has been circulated, via the Executive of the International Union for Quaternary Research (INQUA), to all INQUA members for discussion. It also appears on the ICS web site (www.stratigraphy.org). Comments may be sent to John Clague, President of INQUA (jclague@sfu.ca), and Brad Pillans(brad.pillans@anu.edu.au).

  2. Diagenetic Mineralogy at Gale Crater, Mars

    Science.gov (United States)

    Vaniman, David; Blake, David; Bristow, Thomas F.; Chipera, Steve; Gellert, Ralf; Ming, Douglas; Morris, Richard; Rampe, E. B.; Rapin, William

    2015-01-01

    Three years into exploration of sediments in Gale crater on Mars, the Mars Science Laboratory rover Curiosity has provided data on several modes and episodes of diagenetic mineral formation. Curiosity determines mineralogy principally by X-ray diffraction (XRD), but with supporting data from thermal-release profiles of volatiles, bulk chemistry, passive spectroscopy, and laser-induced breakdown spectra of targeted spots. Mudstones at Yellowknife Bay, within the landing ellipse, contain approximately 20% phyllosilicate that we interpret as authigenic smectite formed by basalt weathering in relatively dilute water, with associated formation of authigenic magnetite as in experiments by Tosca and Hurowitz [Goldschmidt 2014]. Varied interlayer spacing of the smectite, collapsed at approximately 10 A or expanded at approximately 13.2 A, is evidence of localized diagenesis that may include partial intercalation of metal-hydroxyl groups in the approximately 13.2 A material. Subsequent sampling of stratigraphically higher Windjana sandstone revealed sediment with multiple sources, possible concentration of detrital magnetite, and minimal abundance of diagenetic minerals. Most recent sampling has been of lower strata at Mount Sharp, where diagenesis is widespread and varied. Here XRD shows that hematite first becomes abundant and products of diagenesis include jarosite and cristobalite. In addition, bulk chemistry identifies Mg-sulfate concretions that may be amorphous or crystalline. Throughout Curiosity's traverse, later diagenetic fractures (and rarer nodules) of mm to dm scale are common and surprisingly constant and simple in Ca-sulfate composition. Other sulfates (Mg,Fe) appear to be absent in this later diagenetic cycle, and circumneutral solutions are indicated. Equally surprising is the rarity of gypsum and common occurrence of bassanite and anhydrite. Bassanite, rare on Earth, plays a major role at this location on Mars. Dehydration of gypsum to bassanite in the

  3. Rare earth element records from core sediments of southern Pearl River Delta: Geochemical response to palaeoenvironmental changes during the Late Quaternary%珠江三角洲南部晚第四纪环境变化的稀土元素记录

    Institute of Scientific and Technical Information of China (English)

    刘春莲; 吴洁; 杨婷婷; Franz T Fürsich; 张素青

    2011-01-01

    The rare earth element (BEE) distribution in Core PRD05 is closely related to sedimentary environmental changes during the Late Quaternary in the southern Pearl River Delta. Before approximately 31 000 cai a BP, a fluvial setting developed in the study area. The sediments have a lower ∑REE concentration and show HREE enrichment, which are effects of grain size and heavy mineral concentration. The sediments dated to 31 000 to 16 600 cai a BP were possibly deposited in a brackish-water environment, with a high ∑REE and a clear enrichment of LREE relative to HREE. The upper part of these sediments underwent subaerial weathering and erosion during the last glacial maximum. Their REE pattern is subparallel to that of the lower part of sediments, with a slightly higher enrichment of LREE. During the first phase of the postglacial sea-level rise (from around 16600 to 10300 cal a BP), a swamp environment developed in the study area. Organic-rich conditions resulted in high ∑REE concentrations.Since 10 300 cai a BP, an estuarine environment with short-term fluctuations developed and persisted until 5600 cai a BP. Correspondingly, the sediments generally exhibit an enrichment of ∑REE, particularly LREE. A fluvial environment developed at around 5600 cai a BP, and was succeeded by an alluvial plain setting with occasional tidal influence. REE concentrations strikingly decreased and frequently fluctuated.%珠江三角洲南部平原PRD05孔稀土元素(REE)的分布特征与晚第四纪沉积环境变化密切相关.随着不同时期沉积环境的波动,稀土元素分布也发生相应的变化.约31 000 cal a BP以前,研究区发育河流环境,受矿物组成和沉积物粒度的影响,∑REE含量偏低,且重稀土元素(HREE)相对富集.31 000-16600cal a BP期间,∑REE含量明显高于前一阶段,并显示轻稀土元素(LREE)富集;稀土元素分布模式表现为河口半咸水环境特征;其上部沉积物经历了末次冰盛期的风化作用,稀

  4. Mineralogical and geochemical aspects of the marine sediments off Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.

    -Mati beaches and off Mandovi and Zuari Rivers indicates predominant metamorphic source rocks. In the nearshore areas the concentrations of organic carbon and phosphorus have been controlled by detrital supply and organic productivity and that of carbonate...

  5. Oribatid mite fossils from pre-Quaternary sediments in Slovenian caves II. Amiracarus pliocennatus n.gen., n.sp. (Microzetidae) from Pliocene, with comments on the other species of the genus.

    Science.gov (United States)

    Miko, Ladislav; Mourek, Jan; Meleg, Ioana N; Moldovan, Oana T

    2013-01-01

    Amiracarus pliocennatus n. gen., n. sp. is described based on fossils found in Pliocene and Pleistocene clastic sediments in caves of the Slovenian Classical Karst (Kras). Diagnosis and relationships of the new genus are given and relationships within the extant species of the genus are discussed as well as variability and reliability of some characters, used for species differentiation. Amiracarus senensis (Bernini 1975) n. comb. is proposed as a type species of the new genus, and other four extant species are newly placed in Amiracarus n. gen.: A. abeloosi (Lions 1978) n. comb., A. discrepans (Mahunka 1966) n. comb., A. grootaerti (Wauthy &Ducarme 2011) n. comb. and A. similis (Subìas & Iturrondobeitia 1978) n. comb. Finding of a fossil individual of M. senensis Bernini 1975 in Ponicova Cave of South-West Carpathians in Romania is reported and a description of this individual is given. Relationships with the genus Miracarus Kunst 1959 are discussed and a new diagnosis of this genus is also given, along with the redescription of its type species, M. hurkai Kunst 1959.

  6. Clay mineralogy, organic carbon burial, and redox evolution in Proterozoic oceans

    Science.gov (United States)

    Tosca, Nicholas J.; Johnston, David T.; Mushegian, Alexandra; Rothman, Daniel H.; Summons, Roger E.; Knoll, Andrew H.

    2010-03-01

    Clay minerals formed through chemical weathering have long been implicated in the burial of organic matter (OM), but because diagenesis and metamorphism commonly obscure the signature of weathering-derived clays in Precambrian rocks, clay mineralogy and its role in OM burial through much of geologic time remains incompletely understood. Here we have analyzed the mineralogy, geochemistry and total organic carbon (TOC) of organic rich shales deposited in late Archean to early Cambrian sedimentary basins. Across all samples we have quantified the contribution of 1 M and 1 Md illite polytypes, clay minerals formed by diagenetic transformation of smectite and/or kaolinite-rich weathering products. This mineralogical signal, together with corrected paleo-weathering indices, indicates that late Archean and Mesoproterozoic samples were moderately to intensely weathered. However, in late Neoproterozoic basins, 2 M1 illite/mica dominates clay mineralogy and paleo-weathering indices sharply decrease, consistent with an influx of chemically immature and relatively unweathered sediment. A late Neoproterozoic switch to micaceous clays is inconsistent with hypotheses for oxygen history that require an increased flux of weathering-derived clays (i.e., smectite or kaolinite) across the Precambrian-Cambrian boundary. Compared to previous studies, our XRD data display the same variation in Schultz Ratio across the late Neoproterozoic, but we show the cause to be micaceous clay and not pedogenic clay; paleo-weathering signals cannot be recovered from bulk mineralogy without this distinction. We find little evidence to support a link between these mineralogical variations and organic carbon in our samples and conclude that modal clay mineralogy cannot by itself explain an Ediacaran increase in atmospheric oxygen driven by enhanced OM burial.

  7. 青藏高原东缘第四纪泥石流沉积物地球化学分析%The Geochemistry Analysis of the Debris Flow Sediment in the Quaternary at the Eastern Fringe of Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    魏东岚; 李永化

    2012-01-01

    以甘肃武都地区、云南小江流域发育的泥石流体为研究对象,采用地球化学元素分析方法,分析不同地区,不同时代泥石流体中化学元素的分布、分配、迁移和富集的规律,并对泥石流沉积物中的硅铝系数(SiO2/Al2O3)、CaCO3含量、pH值、有机质含量所反映的气候变化特点进行了探讨。结果表明:第四纪泥石流的地球化学特征有别于其它类型的第四纪沉积物;青藏高原东缘第四纪泥石流体中SiO2、CaCO3、有机质含量表现为时代越老含量越高,而Al2O3、K2O含量则表现为时代越老含量越低;硅铝系数表现为时代越老越高,显示了第四纪时期该地区气候波动的总体趋势是干燥程度逐渐增加。研究结果对分析青藏高原的阶段性隆升具有一定的借鉴意义。%The debris flow of the Wudu region in Gansu and Xiaojiang River Basin in Yunnan was taken as study Sites.By geochemical analysis,the chemical elements distribution,allocation and migration of chemical elements in debris flow in different times at different areas were investigated.Then the characteristics of climate change which influenced by the SiO2/Al2O3,the content of CaCO3,pH and organic matter in the sediment of debris flows were analyzed.The results showed that the geochemistry features of debris flow in Quaternary were distinct from other types of sediment.With the ages varying from oldness to youth,the content of SiO2,the content of CaCO3 and organic matter changed from high to low values,whereas the content of Al2O3 and the content of K2O increased.The SiO2/Al2O3 in debris flow became low from old to new ages,which showed that the tendency of climatic change became dry in this regional of Quaternary period.This result have some referential significance for the analysis of the uplift of Tiber.

  8. Late Quaternary glaciation of the Upper Soca River Region (Southern Julian Alps, NW Slovenia)

    Science.gov (United States)

    Bavec, Milos; Tulaczyk, Slawek M.; Mahan, Shannon; Stock, Gregory M.

    2004-01-01

    Extent of Late Quaternary glaciers in the Upper Soc??a River Region (Southern Julian Alps, SE Europe) has been analyzed using a combination of geological mapping, glaciological modeling, and sediment dating (radiocarbon, U/Th series and Infrared Stimulated Luminescence-IRSL). Field investigations focused mainly on relatively well preserved Quaternary sequences in the Bovec Basin, an intramontane basin located SW of the Mediterranean/Black Sea divide and surrounded by mountain peaks reaching from approximately 2100 up to 2587 m a.s.l. Within the Basin we recognized two Late Quaternary sedimentary assemblages, which consist of the same facies association of diamictons, laminated lacustrine deposits and sorted fluvial sediments. Radiocarbon dating of the upper part of the lake sediments sequence (between 12790??85 and 5885??60 14C years b.p.) indicates that the younger sedimentary assemblage was deposited during the last glacial maximum and through early Holocene (Marine Isotope Stage 21, MIS 2-1). Sediment ages obtained for the older assemblage with U/Th and IRSL techniques (between 154.74??22.88 and 129.93??7.90 ka b.p. for selected samples) have large errors but both methods yield results consistent with deposition during the penultimate glacial-interglacial transition (MIS 6-5). Based on analyses of field data combined with glaciological modeling, we argue that both sediment complexes formed due to high sediment productivity spurred by paraglacial conditions with glaciers present in the uplands around the Bovec Basin but not extending down to the basin floor. Our study shows that the extent and intensity of direct glacial sedimentation by Late Quaternary glaciers in the region was previously significantly overestimated. ?? 2004 Elsevier B.V. All rights reserved.

  9. Quaternary rhyolite from the Mineral Mountains, Utah, USA. Final report, Volume 77-10

    Energy Technology Data Exchange (ETDEWEB)

    Evans, S.H. Jr.; Nash, W.P.

    1978-03-01

    A suite of silicic volcanic rocks is associated with the Roosevelt Hot Springs geothermal area in southwestern Utah. The volcanic sequence includes Tertiary rhyolite 8 My old and obsidian, ash and rhyolite of Quaternary age. The Quaternary lavas are characterized by high silica content (76.5% Si0/sub 2/) and total alkalies in excess of 9 percent. Obsidians commonly contain greater amounts of fluorine than water. Two older flows (0.8 My) can be distinguished from younger dome and pyroclastic material (approximately 0.5 My) by subtle differences in their chemistry. The mineralogy of the rhyolites consists of alkali feldspar, plagioclase, and small amounts of Fe-Ti oxides, biotite, hornblende and rare allanite. Fe-Ti oxide temperatures are 740 to 785/sup 0/C for the flows and 635 to 665/sup 0/C for the domes; two feldspar temperatures give similar results. The phase relationships of bulk rock, glass and feldspar compositions demonstrate that the younger Quaternary rhyolites could have been derived from the earlier magma type, represented by the obsidian flows, by a process of crystal fractionation. The major phases which must fractionate are alkali feldspar, plagioclase and quartz with minor amounts of biotite, magnetite and ilmenite participating also. Trace element patterns support this scheme as well. The Tertiary lavas cannot be related to the Quaternary rhyolites and are thought to represent a separate event.

  10. Phobos surface spectra mineralogical modeling

    Science.gov (United States)

    Pajola, M.; Lazzarin, M.; Dalle Ore, C. M.; Cruikshank, D. P.; Roush, T. L.; Pendleton, Y.; Bertini, I.; Magrin, S.; Carli, C.; La Forgia, F.; Barbieri, C.

    2014-04-01

    A mineralogical model composed of a mixture of Tagish Lake meteorite (TL) and Pyroxene Glass (PM80) was presented in [1] to explain the surface reflectance of Phobos from 0.25 to 4.0 μm. The positive results we obtained, when comparing the OSIRIS data [2] extended in wavelength to include the [3,4] spectra, forced us to perform a wider comparison between our TL-PM80 model and the CRISM and OMEGA Phobos spectra presented in [5]. Such spectra cover three different regions of interest (ROIs) situated in the Phobos sub-Mars hemisphere: the interior of the Stickney crater, its eastern rim, and its proximity terrain southeast of the Reldresal crater. We decided to vary the percentage mixture of the components of our model (80% TL, 20% PM80), between pure TL and pure PM80, by means of the radiative transfer code based on the [6] formulation of the slab approximation. Once this spectral range was derived, see Fig. 1, we attempted to compare it with the [5] spectra between 0.4 and 2.6 μm, i.e. below the thermal emitted radiation, to see if any spectral match was possible. We observed that CRISM scaled spectra above 1.10 μm fall within pure Tagish Lake composition and the [1] model. The CRISM data below 1.10 μm present more discrepancies with our models, in particular for the Stickney's rim spectrum. Nevertheless the TL and PM80 components seem to be good mineralogical candidates on Phobos. We performed the same analysis with the OMEGA data and, again, we found out that the Stickney's rim spectrum lies out of our model range, while the two remaining spectra still lie between pure TL and 80% TL - 20% PM80, but indicating that a different, more complicated mixture is expected in order to explain properly both the spectral trend and the possible absorption bands located above 2.0 μm. Within this analysis, we point out that a big fraction of TL material (modeled pure or present with a minimum percentage of 80% mixed together with 20% PM80) seems to explain Phobos spectral

  11. Asignación sistemática y paleocomunidades inferidas a partir del estudio fitolítico de sedimentos cuaternarios de Entre Ríos, Argentina Systematic assignation and paleocommunities inferred by a phytolite study of quaternary sediments from Entre Ríos, Argentina

    Directory of Open Access Journals (Sweden)

    Georgina Erra

    2010-12-01

    Full Text Available El análisis de los fitolitos es una de las disciplinas paleobotánicas utilizadas para la reconstrucción de ecosistemas pasados ya que proporcionan un registro preciso de una parte de la vegetación, en áreas concretas y en un momento determinado. Teniendo en cuenta la importancia de estos análisis se estudió la composición y variabilidad fitolítica de los sedimentos loéssicos cuaternarios de la Formación Tezanos Pinto en el sudoeste de la provincia de Entre Ríos. Los datos de base obtenidos permitieron caracterizar la paleocomunidad existente al momento de depositación de los sedimentos loéssicos. Las formas encontradas corresponden tanto a microfitolitos como a macrofitolitos, siendo del tipo bilobados y polilobados (asignables a gramíneas de la subfamilia Panicoideae, tipo saddle (subfamilia Chloridoideae y tipo cónico o rondel (subfamilia Pooideae. También fueron hallados fitolitos provenientes de pelos, aguijones y ganchos, de células buliformes y de células largas (todos tipos celulares de origen epidérmico de gramíneas sin capacidad diagnóstica para diferenciar subfamilias, y otros producidos por taxones no graminoides (esféricos equinados provenientes de la familia Arecaceae.Phytolith analysis is one of the paleobotanic disciplines used for the reconstruction of past ecosystems, because they provide a precise record of part of the vegetation for a specific time and place. In this context, the composition and variability of phytoliths in Quaternary loessic sediments from the Tezanos Pinto Formation in southwestern Entre Ríos province was studied. The data obtained allowed characterizing the paleocommunity that existed at the time when the loessic sediments were deposited. The found forms correspond to microphytoliths and to macrophytoliths, being of the bilobate and polylobate type (described for Poaceae subfamily Panicoideae, saddle type (subfamily Chloridoideae and conical or rondel type (subfamily Pooideae. Also

  12. Late Quaternary geomorphic history of a glacial landscape - new sedimentary and chronological data from the Cordillera de Cochabamba (Bolivia)

    Science.gov (United States)

    May, J.-H.; Preusser, F.; Zech, R.; Ilgner, J.; Veit, H.

    2009-04-01

    Throughout the Central Andes, glacial landscapes have long been used for the reconstruction of Late Quaternary glaciations and landscape evolution. Much work has focused on the Andes in Peru, Chile and the Bolivian Altiplano, whereas relatively little data has been published on glaciation history in the eastern Andean ranges and slopes. Even less is known with regard to the postglacial evolution of these glacial landscapes. In the Cordillera de Cochabamba (Bolivia), local maximum advances probably peaked around 20-25 ka BP and were followed by significant readvances between ~12-16 ka BP. This generally points to temperature controlled maximum glacial advances along the humid eastern slopes of the Central Andes, which is supported by glacier-climate-modelling studies. However, most studies include only marginal information with regard to the complex geomorphic and sedimentary situation in the Cordillera de Cochabamba. Furthermore, the chronological results are afflicted with several methodological uncertainties inherent to surface exposure dating and call for application of alternative, independent age dating methods. Therefore this study aims at i) documenting and interpreting the complex glacial geomorphology of the Huara Loma valley in the Cordillera de Cochabamba (Bolivia), ii) analyzing the involved units of glacial sediments, and iii) improving the chronological framework by applying optically stimulated luminescence (OSL) and radiocarbon dating (14C). For this purpose, geomorphic mapping was combined with field documentation of sedimentary profiles. The involved sediments were subject to geochemical and mineralogical analysis in order to deduce information on their erosional and weathering histories. In addition, the interpretation of OSL ages from glacial and proglacial sediments integrated several methodological procedures with regard to sample preparation and statistical analysis of the measurements in order to increase the degree of confidence. These

  13. Microstructure development in Al-Cu-Ag-Mg quaternary alloy

    Science.gov (United States)

    Zhou, Bin; Froyen, L.

    2012-01-01

    The solidification behaviour of multi-component and multi-phase systems has been largely investigated in binary and ternary alloys. In the present study, a quaternary model system is proposed based on the well known Al-Cu-Ag and Al-Cu-Mg ternary eutectic alloys. The quaternary eutectic composition and temperature were determined by EDS (Energy Dispersive Spectrometry) and DSC (Differential Scanning Calorimetry) analysis, respectively. The microstructure was then characterised by SEM (Scanning Electron Microscope). In the DSC experiments, two types of quaternary eutectics were determined according to their phase composition. For each type of eutectic, various microstructures were observed, which result in different eutectic compositions. Only one of the determined eutectic compositions was further studied by the controlled growth technique in a vertical Bridgeman type furnace. In the initial part of the directionally solidified sample, competing growth between two-phase dendrites and three-phase eutectics was obtained, which was later transformed to competing growth between three-phase and four-phase eutectics. Moreover, silver enrichment was measured at the solidification front, which is possibly caused by Ag sedimentation due to gravity and Ag rejection from dendritic and three-phase eutectic growth, and its accumulation at the solidification front.

  14. Tectonic, climatic and hydrothermal control on sedimentation and water chemistry of northern Lake Malawi (Nyasa), Tanzania

    Science.gov (United States)

    Branchu, Philippe; Bergonzini, Laurent; Delvaux, Damien; De Batist, Marc; Golubev, Vladimir; Benedetti, Marc; Klerkx, Jean

    2005-11-01

    This paper presents a multi-disciplinary characterisation of processes that influence sedimentation and lake water chemistry in the northern part of the Lake Malawi (or Lake Nyasa), East Africa. This characterisation is based on geophysical (heat-flow), tectonic, hydrological, hydrochemical (major elements, stable isotopes) and sedimentological (seismic profiles, core mineralogy) studies of data acquired from 1990 to 1994 during the CASIMIR project (Comparative Analysis of Sedimentary Infill Mechanisms in Rifts). Sub-surface activity is expressed through seismic and volcanic activity, as well as elevated heat-flow values, both beneath the lake and the surrounding area; hydrothermal activity is observed in the watershed however it was not clearly identified in the sub-lacustrine environment. Relatively high heat-flow values (80-90 mW/m 2) and the chemical composition of hydrothermal fluids in hot springs suggest the presence of a magmatic body at depth. The influence of Quaternary tectonic activity on sedimentary dynamics and infilling is observed not only on land but also in the lake through high-resolution seismic profiles. The main feature is a general tilting of the Kyela Plain as shown by a shift in the river course. The Quaternary stacking pattern of seven sedimentary sequences identified on a grid of high-resolution seismic reflection profiles represents a complete long-term lake-level cycle, from a lake lowstand at about 320 m below the present level to the present-day lake highstand. The North-Kiwira and Songwe River delta systems, composed of a number of stacked lobes, were developed in response to the interplay between gradual lake-level rise, tectonic movement and sediment input. The river dynamics is also recorded in a short core by a mineralogical evolution probably due to a decrease of detrital inputs from the Songwe River in response to hydroclimatic changes. Such changes are very important as this northern part of the watershed is considered as a

  15. Quaternary tectonic movements in the Argentine Puna, 24/sup 0/ to 27/sup 0/ s latitude

    Energy Technology Data Exchange (ETDEWEB)

    Strecker, M.R.; Alonso, R.; Rivelli, F.; Mon, R.

    1985-01-01

    The Puna of NW Argentina, one of the highest plateaus in the world, is the southern continuation of the Andean Altiplano geomorphic province of Peru and Bolivia. The region is not seismically active and reports of neotectonic movements are scarce. However, the areas of Salar de los Pastos Grandes, Salar del Hombre Muerto and Sierra Calalaste clearly have experienced Quaternary tectonic movements. At Salar de los Pastos Grandes, early Pleistocene lake sediments are offset by reverse faulting. At Salar del Hombre Muerto, Quaternary pyroclastic and debris-flow deposits are unconformable over sediments 5.86 m.y. old that were folded during the Pliocene-Pleistocene Diaguita deformation. Within the Quaternary sediments two separate deformational phases with reverse faulting and shallow thrusting are recognized. The timing of movement is well defined since the deformed strata are covered by a basalt flow 0.75 m.y. old. The flow in turn is affected by normal faulting. Similar normal faults associated with basalt flows were found at Sierra Calalaste. These observations are in accord with pronounced extensional movements and basaltic volcanism at the Calama-Olacapato-Toro Lineament (0.2 m.y. old flows) and might document the Quaternary transition from a compressive to an extensional tectonic regime in the southern Puna.

  16. Coupling among Microbial Communities, Biogeochemistry, and Mineralogy across Biogeochemical Facies

    Energy Technology Data Exchange (ETDEWEB)

    Stegen, James C.; Konopka, Allan; McKinely, Jim; Murray, Christopher J.; Lin, Xueju; Miller, Micah D.; Kennedy, David W.; Miller, Erin A.; Resch, Charles T.; Fredrickson, Jim K.

    2016-07-29

    Physical properties of sediments are commonly used to define subsurface lithofacies and these same physical properties influence subsurface microbial communities. This suggests an (unexploited) opportunity to use the spatial distribution of facies to predict spatial variation in biogeochemically relevant microbial attributes. Here, we characterize three biogeochemical facies—oxidized, reduced, and transition—within one lithofacies and elucidate relationships among facies features and microbial community biomass, diversity, and community composition. Consistent with previous observations of biogeochemical hotspots at environmental transition zones, we find elevated biomass within a biogeochemical facies that occurred at the transition between oxidized and reduced biogeochemical facies. Microbial diversity—the number of microbial taxa—was lower within the reduced facies and was well-explained by a combination of pH and mineralogy. Null modeling revealed that microbial community composition was influenced by ecological selection imposed by redox state and mineralogy, possibly due to effects on nutrient availability or transport. As an illustrative case, we predict microbial biomass concentration across a three-dimensional spatial domain by coupling the spatial distribution of subsurface biogeochemical facies with biomass-facies relationships revealed here. We expect that merging such an approach with hydro-biogeochemical models will provide important constraints on simulated dynamics, thereby reducing uncertainty in model predictions.

  17. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  18. 钱塘江河口区晚第四纪古环境演化及其元素地球化学特征%PALEOENVIRONMENT EVOLUTION DURING THE LATE QUATERNARY IN THE QIANTANG RIVER MOUTH AREA: EVIDENCE FROM THE SE2 CORE SEDIMENT AND ITS RARE EARTH ELEMENTS GEOCHEMISTRY

    Institute of Scientific and Technical Information of China (English)

    李艳丽; 林春明; 张霞; 周健; 曲长伟; 潘峰; 姚玉来

    2011-01-01

    In 2009, a 51. 5-m-long core SE2 was drilled at 120°21'57" E, 30°12'38" N, from the Kanshan town, Hangzhou city, in the south bank of the Qiantang River. The ground surface elevation of the core is 6. Om above mean sea level. Core SE2,10. 8cm in diameter,was obtained by rotary drilling with a 96% recovery. A total of 294 samples were collected at 10 ~20cm intervals along the cored succession for grain size analysis,93 samples at 20 ~ 80cm intervals for foraminifera identification, and 27 samples at 200cm intervals for rare earth elements analysis. The lithology, grain size, sedimentary structure, foraminifera, and rare earth elements of Late Quaternary sediments in the borehole SE2 were analyzed to research the sedimentary environment evolution, and the associated distribution variation of rare earth elements in the Qiantang River mouth area. The results indicate that five sedimentary facies, including fluvial channel,floodplain,tidal flat,shallow marine,and estuarine sand bar,can be distinguished,and the rare earth elements distribution is closely related to sedimentary environment. Fluvial channel facies consists of sandy gravel,gravelly sand, and fine sand, with high content of rolling and saltation population. Foraminifera are absent. The sediments have the lowest total rare earth elements content in all sedimentary facies,and high light rare earth elements concentration. The fractionation degree of light and heavy rare earth elements, and fractionation degree of heavy rare earth elements are positively related with the total rare earth elements content. The fractionation of light rare earth elements shows negative correlation with the total rare earth elements content, heavy rare earth elements concentration, the fractionation of light and heavy rare earth elements, and fractionation in heavy rare earth elements. Floodplain facies are dominated by clay, with foraminifera and rolling population absent. Total rare earth elements content is the highest. The

  19. STUDY ON STARTING VELOCITY OF COHESIVE SEDIMENTATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, with the starting velocity experiments of natural cohesive sedimentation, the author proposes an assumption concerning the starting mechanism of cohesive sedimentation and gives a formula to determine the starting velocity of compact clay. It is pointed out that the fluctuating function of flow is a main factor for the starting of sedimentation. And the component and the structure of cohesive sedimentation are also the affecting factors for the starting. Consequently, the study shows that modern results of soil mechanics, clay mineralogy and fluid mechanics are helpful in the investigation of this kind of engineering problem.

  20. Mineralogical and geochemical influences on sediment color of Amazon wetlands analyzed by visible spectrophotometry Influências mineralógicas e geoquímicas na cor dos sedimentos das zonas úmidas da Amazônia analisada através da espectrofotometria no visível

    Directory of Open Access Journals (Sweden)

    José Tasso Felix Guimarães

    2013-09-01

    Full Text Available Based on sedimentological and geochemical data, this work relates spectrophotometric measurements with sediment composition and its application in palaeoecological studies of Amazon wetlands. The CIELAB values are directly related to mineralogical and chemical composition, mostly involving quartz, iron oxyhydroxides and sulfides (e.g. pyrite, and total organic carbon. Total organic carbon contents between 0.4-1%, 1-2%, 3-5% and 15-40% were related to L* (lightness data of 27, 26-15, 7-10 and 7 or less, respectively. The CIELAB values of a deposit in Marabá, Pará, were proportional to variations in quartz and total organic carbon contents, but changes in zones of similar color, mainly in the +a* (red and +b* (yellow values of deposits in Calçoene, Amapá and Soure, Pará, indicate a close relationship between total organic carbon content and iron oxyhydroxides and sulfides. Furthermore, the Q7/4 diagram (ratio between the % re?ectance value at 700 nm to that at 400 nm, coupled with L* indicated iron-rich sediments in the bioturbated mud facies of the Amapá deposit, bioturbated mud and bioturbated sand facies of Soure deposit, and cross-laminated sand and massive sand facies of the Marabá core. Also, organic-rich sediments were found in the bioturbated mud facies of the Amapá deposit, lenticular heterolithic and bioturbated mud facies of the Soure deposit, and laminated mud and peat facies of the Marabá deposit. At the Marabá site, the data suggest an autochthonous influence with peat formation. The coastal wetland sites at Marajó and Amapá represent the development of a typical tidal flat setting with sulfide and iron oxyhydroxides formation during alternated flooding and drying.Com base em dados sedimentológicos e geoquímicos, este trabalho relaciona medições espectrofotométricas com a composição do sedimento, e sua aplicação em estudos paleoecológicos das áreas alagáveis da Amazônia. Os dados CIELAB estão diretamente

  1. Mineralogical Controls on Carbon Cycling in a Floodplain Environment

    Science.gov (United States)

    Arora, B.; Dwivedi, D.; Steefel, C. I.; Spycher, N.; Fox, P. M.; Nico, P. S.

    2016-12-01

    With the overarching goal of understanding mineral-organic-microbe interactions on carbon and nutrient cycles, we are developing a reactive transport model that includes carbon (C) pools and transformations, a realistic treatment of protected C pools, multiple decomposition pathways, and radiocarbon (14C) dynamics. The objective of the modeling is to understand the impact of mineralogy on carbon turnover and residence times in a floodplain site in Rifle, CO. Previous studies have identified naturally reduced zones (NRZs) in the saturated zone of the Rifle site to be C hotspots and regions characterized by diffusion-limited transport and high rates of microbially-mediated biogeochemical reactions. Detailed characterization of the soil organic matter in both the NRZ and non-NRZ sediments at the Rifle site including radiocarbon dating, and extraction and chemical characterization of mineral-bound pool of organic matter, is used to inform the modeling. In this study, we describe the development of a coupled unsaturated-saturated flow and biogeochemical reactive transport model of the Rifle site along a two-dimensional cross-section (parallel to groundwater flow). The biogeochemical reaction network includes representations of bacterial and fungal activity, archetypal polymer and monomer carbon substrate groups, kinetic and equilibrium mineral precipitation and dissolution reactions, and aqueous and surface complexation. We use this model to explore fungal and bacterial community emergence at the site and compare organo-mineral interactions across NRZ and non-NRZ regions. Observed 14C profiles suggest that sediment-associated carbon in NRZ locations is much older than both the depositional age of the floodplain sediments and dissolved organic carbon in the groundwater. Model simulations were able to capture the observed soil organic matter (SOM) and ∆14C profiles across the Rifle site. Modeling results show higher lignin content in the NRZ sediments and greater Fe

  2. Effect of grain-coating mineralogy on nitrate and sulfate storage in the unsaturated zone

    Science.gov (United States)

    Reilly, T.J.; Fishman, N.S.; Baehr, A.L.

    2009-01-01

    Unsaturated-zone sediments and the chemistry of shallow groundwater underlying a small (???8-km2) watershed were studied to identify the mechanisms responsible for anion storage within the Miocene Bridgeton Formation and weathered Coastal Plain deposits in southern New Jersey. Lower unsaturated-zone sediments and shallow groundwater samples were collected and concentrations of selected ions (including NO3- and SO42-) from 11 locations were determined. Grain size, sorting, and color of the lower unsaturated-zone sediments were determined and the mineralogy of these grains and the composition of coatings were analyzed by petrographic examination, scanning electron microscopy and energy dispersive analysis of x-rays, and quantitative whole-rock x-ray diffraction. The sediment grains, largely quartz and chert (80-94% w/w), are coated with a very fine-grained (Soil Science Society of America. All rights reserved.

  3. Reconstructing the Holocene depositional environments along the northern coast of Sfax (Tunisia): Mineralogical and sedimentological approaches

    Science.gov (United States)

    Lamourou, Ali; Touir, Jamel; Fagel, Nathalie

    2017-05-01

    A sedimentological and mineralogical study of sedimentary cores allowed reconstructing the evolution of depositional environments along the Northern coast of Sfax (Tunisia). The aim of this research work is to identify the factors controlling the sedimentation from the Holocene to the Present time. Three 30-m sediment cores collected by drilling at 30 m water depth were analyzed for their color, magnetic susceptibility signal, grain size by laser diffraction, organic matter content by loss of ignition, carbonate content by calcimetry and mineralogy by X-ray diffraction on bulk powder and clay <2 μm. They broadly present the same sedimentological and mineralogical features. Microscopical observations of petrographic slides allowed identifying six main sedimentary facies. Bulk mineralogical assemblages comprised clay minerals, quartz, calcite, gypsum and K-feldspars were examined. Considerable change was observed in the carbonate content that mimicked the bioclaste abundance and diluted the detrital minerals (clay minerals, quartz and feldspars). The gypsum mainly occurred in the lower sedimentary columns (SC12 and SC9) and in the upper/middle of core SC6. The clay fraction was made of a mixture of kaolinite, illite, smectite and palygorskite with no clear variation through core depth. Both grain-size parameters and magnetic susceptibility profile showed a sharp transition in the upper 2-5 m of the sedimentological columns. Coarse, sandy to gravely sediments characterized by a low magnetic susceptibility signal were replaced by fine bioclastic-rich clayey sediments. The analysis of vertical succession of depositional facies revealed a fluvial depositional environment (coastal plain) basically marked by fluvial channels and inundation plains at the bottom of all cores. However, core-top sediments recorded a littoral marine environment with sand depositions rich in gastropods, lamellibranches and algæ. Depositional facies, sedimentological and mineralogical

  4. Gold process mineralogy: Objectives, techniques, and applications

    Science.gov (United States)

    Zhou, Joe Y.; Cabri, Louis J.

    2004-07-01

    The extractive metallurgy of gold is largely driven by mineralogical factors such as gold particle size; association with other minerals; coatings; presence of cyanicides, oxygen consumers, and preg-robbers; presence of refractory gold minerals; and locking of submicroscopic gold in sulfide and sulfarsenide mineral structures. Gold process mineralogy addresses all issues related to gold ore processing by the detailed study of an ore or a mill product. The methodology is widely used as a predictive tool in feasibility studies and during the process development stage, and as a trouble-shooting tool for mineral processing and hydrometallurgical operations.

  5. Late Quaternary eolian dust in surficial deposits of a Colorado Plateau grassland: Controls on distribution and ecologic effects

    Science.gov (United States)

    Reynolds, R.L.; Reheis, M.C.; Neff, J.C.; Goldstein, H.; Yount, J.

    2006-01-01

    In a semi-arid, upland setting on the Colorado Plateau that is underlain by nutrient-poor Paleozoic eolian sandstone, alternating episodes of dune activity and soil formation during the late Pleistocene and Holocene have produced dominantly sandy deposits that support grass and shrub communities. These deposits also contain eolian dust, especially in paleosols. Eolian dust in these deposits is indicated by several mineralogic and chemical disparities with local bedrock, but it is most readily shown by the abundance of titaniferous magnetite in the sandy deposits that is absent in local bedrock. Magnetite and some potential plant nutrients (especially, P, K, Na, Mn, and Zn) covary positively with depth (3-4 m) in dune-crest and dune-swale settings. Magnetite abundance also correlates strongly and positively with abundances of other elements (e.g., Ti, Li, As, Th, La, and Sc) that are geochemically stable in these environments. Soil-property variations with depth can be ascribed to three primary factors: (1) shifts in local geomorphic setting; (2) accumulation of relatively high amounts of atmospheric mineral dust inputs during periods of land-surface stability; and (3) variations in dust flux and composition that are likely related to changes in dust-source regions. Shifts in geomorphic setting are revealed by large variations in soil texture and are also expressed by changes in soil chemical and magnetic properties. Variable dust inputs are indicated by both changes in dust flux and changes in relations among magnetic, chemical, and textural properties. The largest of these changes is found in sediment that spans late Pleistocene to early Holocene time. Increased dust inputs to the central Colorado Plateau during this period may have been related to desiccation and shrinkage of large lakes from about 12 to 8 ka in western North America that exposed vast surfaces capable of emitting dust. Soil properties that result from variable dust accumulation and redistribution

  6. The late Quaternary tephrostratigraphical record of the San Gregorio Magno basin (southern Italy)

    Science.gov (United States)

    Munno, R.; Petrosino, P.

    2007-03-01

    Twenty-one primary pyroclastic layers were found embedded in the lacustrine sediments of the San Gregorio Magno basin (Southern Apennines). These sand-sized layers were characterised by a noticeable juvenile fragments content and by a sharp basal contact with the underlying clay and silt sediments. The tephra layers have been correlated with terrestrial counterparts from well-known eruptive events of the Campanian volcanic area, or with reference layers from deep sea sediment cores and from the Monticchio maar sequence. The investigation of the San Gregorio Magno tephra layers made it possible to deduce that lacustrine sedimentation at San Gregorio Magno basin began before 170k yr BP and lasted at least until the emplacement of the Neapolitan Yellow Tuff, which occurred about 15k yr BP. The tephrochronology allowed determination of the varying sedimentation rate that occurred in the basin. Correlation of the lacustrine record with marine sequences has allowed development of a late Quaternary tephrostratotype for southern Italy. Copyright

  7. Late Quaternary faunal change in coastal Arabian sea sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Borole, D.V.; Rao, K.K.; Krishnamurthy, R.V.; Somayajulu, B.L.K.

    Carbonate content and faunal composition of two gravity cores from the coastal Arabian Sea provide evidence of a major environmental change in surface ocean waters about 13,000 yr B.P. Radiocarbon dating indicates that deposition rates ranged from 1...

  8. Novel Quaternary Quantum Decoder, Multiplexer and Demultiplexer Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2017-05-01

    Multiple valued logic is a promising approach to reduce the width of the reversible or quantum circuits, moreover, quaternary logic is considered as being a good choice for future quantum computing technology hence it is very suitable for the encoded realization of binary logic functions through its grouping of 2-bits together into quaternary values. The Quaternary decoder, multiplexer, and demultiplexer are essential units of quaternary digital systems. In this paper, we have initially designed a quantum realization of the quaternary decoder circuit using quaternary 1-qudit gates and quaternary Muthukrishnan-Stroud gates. Then we have presented quantum realization of quaternary multiplexer and demultiplexer circuits using the constructed quaternary decoder circuit and quaternary controlled Feynman gates. The suggested circuits in this paper have a lower quantum cost and hardware complexity than the existing designs that are currently used in quaternary digital systems. All the scales applied in this paper are based on Nanometric area.

  9. Novel Quaternary Quantum Decoder, Multiplexer and Demultiplexer Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2017-02-01

    Multiple valued logic is a promising approach to reduce the width of the reversible or quantum circuits, moreover, quaternary logic is considered as being a good choice for future quantum computing technology hence it is very suitable for the encoded realization of binary logic functions through its grouping of 2-bits together into quaternary values. The Quaternary decoder, multiplexer, and demultiplexer are essential units of quaternary digital systems. In this paper, we have initially designed a quantum realization of the quaternary decoder circuit using quaternary 1-qudit gates and quaternary Muthukrishnan-Stroud gates. Then we have presented quantum realization of quaternary multiplexer and demultiplexer circuits using the constructed quaternary decoder circuit and quaternary controlled Feynman gates. The suggested circuits in this paper have a lower quantum cost and hardware complexity than the existing designs that are currently used in quaternary digital systems. All the scales applied in this paper are based on Nanometric area.

  10. Severnaya Zemlya, Arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    NARCIS (Netherlands)

    Moller, P.; Lubinski, D.J.; Ingolfsson, O.; Forman, S.L.; Seidenkrantz, M.S.; Bolshiyanov, D.Y.; Lokrantz, H.; Antonov, O.; Pavlov, M.; Ljung, K.; Zeeberg, J.J.; Andreev, A.

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from

  11. Tectonic and climatic controls on late quaternary sedimentary processes in a neotectonic intramontane basin. (The Pitalito Basin, South Colombia).

    NARCIS (Netherlands)

    Bakker, J.

    1990-01-01

    The present study deals with the influence of tectonics and climatic changes on sedimentation patterns in the Quaternary Pitalito Basin (lat. 1°52'N, long. 76°02'W). This intramontane sedimentary basin is 15 km in width and 20 kin in length and is located in the Eastern Cordillera of the southern Co

  12. Quaternary climate change and Heinrich events in the southern Balkans : Lake Prespa diatom palaeolimnology from the last interglacial to present

    NARCIS (Netherlands)

    Cvetkoska, Aleksandra; Levkov, Zlatko; Reed, Jane M.; Wagner, Bernd; Panagiotopoulos, Konstantinos; Leng, Melanie J.; Lacey, Jack H.

    2015-01-01

    Lake Prespa, in the Balkans, contains an important palaeo-archive in a key location for understanding Quaternary climate variability in the transition between Mediterranean and central European climate zones. Previous palaeoenvironmental research on sediment cores indicates that the lake is highly s

  13. Severnaya Zemlya, arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    DEFF Research Database (Denmark)

    Möller, Per; Lubinski, David J.; Ingólfsson, Ólafur

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from...

  14. Severnaya Zemlya, Arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    NARCIS (Netherlands)

    Moller, P.; Lubinski, D.J.; Ingolfsson, O.; Forman, S.L.; Seidenkrantz, M.S.; Bolshiyanov, D.Y.; Lokrantz, H.; Antonov, O.; Pavlov, M.; Ljung, K.; Zeeberg, J.J.; Andreev, A.

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from ra

  15. The geology, mineralogy and rare element geochemistry of the gem deposits of Sri Lanka

    Directory of Open Access Journals (Sweden)

    C. B. Dissanayake

    2000-01-01

    Full Text Available The gem deposits of Sri Lanka are studied from the point of view of their geology, mineralogy and geochemistry. Nearly all the gem formations are located in the central high-grade metamorphic terrain of the Highland Complex. The gem deposits are classified as sedimentary, metamorphic and magmatic; the sedimentary types being the most abundant. The mineralogy of the gem deposits varies widely with, among others, corundum, chrysoberyl, beryl, spinel, topaz,zircon, tourmaline, garnet and sphene being common.Rare element concentrations in sediments from the three main gem fields of Sri Lanka, namely Ratnapura, Elahera and Walawe, were studied. It was found that some sediments are considerably enriched in certain elements compared to their average continental crustal abundances. The Walawe Ganga sediments show anomalous enrichments of the high field strength and associated elements, particularly Zr, Hf, W and Ti. This is attributed to the presence of accessory mineralssuch as zircon, monazite and rutile. Some of these heavy minerals comprise as much as 50 wt% of sediment. The geochemical enrichment of some trace elements compared to their average crustal abundances indicates that highly differentiated granites and associated pegmatites have provided the source materials for enrichment.

  16. The isotope hydrology of Quaternary climate change.

    Science.gov (United States)

    Darling, W G

    2011-04-01

    Understanding the links between climate change and human migration and culture is an important theme in Quaternary archaeology. While oxygen and hydrogen stable isotopes in high-latitude ice cores provide the ultimate detailed record of palaeoclimate extending back to the Middle Pleistocene, groundwater can act as a climate archive for areas at lower latitudes, permitting a degree of calibration for proxy records such as lake sediments, bones, and organic matter. Not only can oxygen and hydrogen stable isotopes be measured on waters, but the temperature of recharge can be calculated from the amount of the atmospheric noble gases neon, argon, krypton, and xenon in solution, while residence time can be estimated from the decay of the radioisotopes carbon-14, chlorine-36, and krypton-81 over timescales comparable to the ice core record. The Pleistocene-Holocene transition is well characterised in aquifers worldwide, and it is apparent that isotope-temperature relationships of the present day are not necessarily transferable to past climatic regimes, with important implications for the interpretation of proxy isotope data. Groundwaters dating back to one million years, i.e., to beyond the Middle Pleistocene, are only found in major aquifer basins and information is relatively sparse and of low resolution. Speleothem fluid inclusions offer a way of considerably increasing this resolution, but both speleothem formation and large-scale groundwater recharge requires humid conditions, which may be relatively infrequent for areas currently experiencing arid climates. Both types of record therefore require caution in their interpretation when considering a particular archaeological context.

  17. Silicate mineralogy at the surface of Mercury

    Science.gov (United States)

    Namur, Olivier; Charlier, Bernard

    2017-01-01

    NASA's MESSENGER spacecraft has revealed geochemical diversity across Mercury's volcanic crust. Near-infrared to ultraviolet spectra and images have provided evidence for the Fe2+-poor nature of silicate minerals, magnesium sulfide minerals in hollows and a darkening component attributed to graphite, but existing spectral data is insufficient to build a mineralogical map for the planet. Here we investigate the mineralogical variability of silicates in Mercury's crust using crystallization experiments on magmas with compositions and under reducing conditions expected for Mercury. We find a common crystallization sequence consisting of olivine, plagioclase, pyroxenes and tridymite for all magmas tested. Depending on the cooling rate, we suggest that lavas on Mercury are either fully crystallized or made of a glassy matrix with phenocrysts. Combining the experimental results with geochemical mapping, we can identify several mineralogical provinces: the Northern Volcanic Plains and Smooth Plains, dominated by plagioclase, the High-Mg province, strongly dominated by forsterite, and the Intermediate Plains, comprised of forsterite, plagioclase and enstatite. This implies a temporal evolution of the mineralogy from the oldest lavas, dominated by mafic minerals, to the youngest lavas, dominated by plagioclase, consistent with progressive shallowing and decreasing degree of mantle melting over time.

  18. Geological and geomorphological evolution of a sedimentary periglacial landscape in Northeast Siberia during the Late Quaternary

    OpenAIRE

    2007-01-01

    A wide variety of environmental records is necessary for analysing and understanding the complex Late Quaternary dynamics of permafrost-dominated Arctic landscapes. A NE Siberian periglacial key region was studied in detail using sediment records, remote sensing data, and terrain modelling, all incorporated in a geographical information system (GIS). The study area consists of the Bykovsky Peninsula and the adjacent Khorogor Valley in the Kharaulakh Ridge situated a few kilometres southeast o...

  19. SITE-94. Mineralogy of the Aespoe site

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Karin [Chalmers Univ. of Technology, Goeteborg (Sweden). Technical Environmental Planning

    1996-12-01

    The water composition has several impacts on the repository. It will influence the behaviour of the engineered materials (e.g. corrosion). It may also determine the possible solubility and speciation of released radionuclides. It also acts as a transport medium for the released elements. The groundwater composition and the potential development of the composition due to the presence of the repository as well as due to external variations is thus an important issue in a safety analysis. The development of the groundwater composition is strongly dependent on reactions with the minerals present in water bearing fractures. Here equilibrium chemistry may be of importance, but also reaction kinetics is important to the long-term behaviour. Within the SITE-94 project, a safety analysis is performed for the conditions at the Aespoe site. The mineralogy of the area has been evaluated from drill cores at various places at the site. In this report a recommendation for selection of mineralogy to be used in geochemical modelling of the repository is given. Calcite and iron containing minerals dominate the fracture filling mineralogy at the Aespoe site. Some typical fracture filling mineralogies may be identified in the fractures: epidote, chlorite, calcite, hematite, some illite/smectite + quartz, fluorite, pyrite and goethite. In addition to these a number of minor minerals are found in the fractures. Uncertainties in the fracture filling data may be due to problems when taking out the drill cores. Drilling water may remove important clay minerals and sealed fractures may be reopened mechanically and treated as water conducting fractures. The problem of determining the variability of the mineralogy along the flow paths also remains. This problem will never be solved when the investigation is performed by drilling investigation holes

  20. Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

    Science.gov (United States)

    Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.; hide

    2015-01-01

    The Mars Science Laboratory (MSL) rover Curiosity recently completed its fourth drill sampling of sediments on Mars. The Confidence Hills (CH) sample was drilled from a rock located in the Pahrump Hills region at the base of Mt. Sharp in Gale Crater. The CheMin X-ray diffractometer completed five nights of analysis on the sample, more than previously executed for a drill sample, and the data have been analyzed using Rietveld refinement and full-pattern fitting to determine quantitative mineralogy. Confidence Hills mineralogy has several important characteristics: 1) abundant hematite and lesser magnetite; 2) a 10 angstrom phyllosilicate; 3) multiple feldspars including plagioclase and alkali feldspar; 4) mafic silicates including forsterite, orthopyroxene, and two types of clinopyroxene (Ca-rich and Ca-poor), consistent with a basaltic source; and 5) minor contributions from sulfur-bearing species including jarosite.

  1. Quantitative x-ray diffraction mineralogy of Los Angeles basin core samples

    Science.gov (United States)

    Hein, James R.; McIntyre, Brandie R.; Edwards, Brian D.; Lakota, Orion I.

    2006-01-01

    This report contains X-ray diffraction (XRD) analysis of mineralogy for 81 sediment samples from cores taken from three drill holes in the Los Angeles Basin in 2000-2001. We analyzed 26 samples from Pier F core, 29 from Pier C core, and 26 from the Webster core. These three sites provide an offshore-onshore record across the Southern California coastal zone. This report is designed to be a data repository; these data will be used in further studies, including geochemical modeling as part of the CABRILLO project. Summary tables quantify the major mineral groups, whereas detailed mineralogy is presented in three appendices. The rationale, methodology, and techniques are described in the following paper.

  2. Characterisation of some Clays Used for Whiteware Ceramics I. Mineralogical composition

    Directory of Open Access Journals (Sweden)

    Marcel Benea

    2002-04-01

    Full Text Available In order to obtain a semiquantitative mineralogical composition of raw materials used for whiteware ceramics, four different clay types were analysed by X-ray diffraction. Studies were carried out by using a combination of analyses of the bulk sample, and of the fine fraction. Using a well-established pre-treatment methodology (use of chemicals, ultrasonic treatment, dispersion procedures, clay mineral concentration by centrifugation and sedimentation, oriented and random powder preparation, cation saturation, expansion/dehydration methods, 12 X-ray diffractometer traces were obtained from each sample. Based on these informations it was possible to establish the qualitative mineralogical composition, and also a semiquantitative one using peak intensities and peak area corrected by various factors. Scanning electron microscopy was also used in order to illustrate the identified mineral phases.

  3. Buried Quaternary Valleys In NW Europe - Aquifers and Drilling Hazards

    Science.gov (United States)

    Huuse, M.; Lykke-Andersen, H.; Piotrowski, J.

    Buried Quaternary valleys are extremely widespread in the formerly glaciated, low- land areas of NW Europe (Huuse &Lykke-Andersen 2000, Fig. 4). The valleys may be several hundred metres deep, some kilometres across and few to several tens of kilometres long. Most of the deep valleys have irregular length profiles with sills and basins, unlike standard subaerial river systems. We interpret these as overdeepened valleys, formed mainly by subglacial meltwater erosion. Buried valleys located on- shore often provide sheltered reservoirs of clean groundwater, and much attention is presently focused on locating onshore valleys and quantifying their potential as groundwater aquifers. In nearshore areas, buried valleys may be a risk factor by pro- viding pathways of salt-water intrusion of onshore groundwater aquifers. Far offshore, buried valleys are located in the shallow subsurface above the prolific oil and gas fields of the central North Sea. Here, the valleys pose a risk for drilling operations by hosting shallow gas and potentially unstable sediments. The central North Sea is now largely covered by 3D seismic data, which often image the buried valleys in a level of de- tail much greater than that available onshore. Hence offshore valleys imaged by 3D seismic data may be used as analogues for groundwater reservoirs onshore NW Eu- rope. Here, we present examples of buried valleys from onshore, nearshore and far offshore locations, to illustrate how genetically and morphologically identical valleys may benefit or hamper the exploitation of subsurface accummulations of groundwater and hydrocarbons. Huuse, M. &Lykke-Andersen, H. 2000. Buried Quaternary valleys in the eastern Dan- ish North Sea: morphology and origin. Quaternary Science Reviews 19, 1233-1253.

  4. Petrography and petrology of Quaternary volcanic rocks from Ghezel Ghaleh, northwest Qorveh

    Directory of Open Access Journals (Sweden)

    Alireza Bajelan

    2014-10-01

    Full Text Available Introduction In the east and northeast of Sanandaj in the Qorveh-Bijar-Takab axis, there are series of basaltic composition volcanoes with Quaternary age. The study area is part of the Sanandaj-Sirjan zone and is located between 47°52' and 47°57' E longitudes and 35°26 and '35°30' N latitudes. Due to the location of the volcanic cone on Pliocene clastic sediments and Quaternary travertine, the age of these volcanoes is considered to be Quaternary. The cones mostly consist of low scoria, ash, volcanic bombs, lapilli deposits and basaltic lava (Moein Vaziri and Aminsobhani, 1985. Petrological and geochemical studies have been carried out to evaluate Quaternary magmatism in the area and to determine the nature of the lithological characteristics, such as the evaluation of source rocks and magma type, degree of partial melting and the tectonic setting of Ghezel Ghaleh rocks (Moein Vaziri, 1997. Simplified geological map of the study area is characterized by ER-Mapper software. Materials and methods In the course of field studies in the region, 40 samples were taken, 30 thin sections were prepared and polished. XRD analyses were performed on some whole rock samples. All major, minor and trace elements were assessed by ICP-MS at Lab Weft Laboratory in Australia. Results Based on the classification of structural zones, the area is located in the Sanandaj-Sirjan zone, hundred kilometers away from the main Zagros thrust along the NW-SE direction. After early Cimmerian orogeny, andesitic volcanic activity took place (Moein Vaziri and Aminsobhani, 1985. A major secondary mineral in these rocks is iddingsite, formed by hydration and oxidation of the olivine (Shelley, 1993. According to SiO2 against Na2O + K2O (TAS diagram (Irvine and Baragar , 1971 and cationic R1 and R2 diagram (De La Roche et el., 1980, volcanic rocks of the area indicate alkaline series. Discussion To obtain more information on the tectonic setting of these rocks, the Zr/Y-Zr diagram

  5. Late Quaternary carbonate accumulation along eastern South Atlantic Ocean

    Science.gov (United States)

    Crabill, K.; Slowey, N. C.; Foreman, A. D.; Charles, C. D.

    2015-12-01

    Water masses originating from both the North Atlantic Ocean and the Southern Ocean intersect the Walvis Ridge and Namibian margin of southwest Africa. Changes in the distribution and properties of these water masses through time are reflected by variations in the nature of the sediments accumulating along this margin. As part of our ongoing studies, we are investigating the interrelationships between oceanographic/climatic change and the accumulation of carbonate minerals during the late Quaternary. A suite of cores that possess sediment records corresponding to the most recent glacial-interglacial cycles was collected from the water depth range of 500 to 3000 meters. Cores that preserve records of key water masses were selected for detailed analyses. Sediment bulk density, the concentration of calcium carbonate, and the relative proportions of carbonate minerals were precisely determined at regular depth intervals in these cores. Foraminiferal d18O and C-14 dates provide chronologic control. Results will be used to calculate how the accumulation rates of carbonate minerals on the seafloor vary through time, and the correspondence of such variation to changes in ocean circulation and climate will be assessed.

  6. Of ice and water: Quaternary fluvial response to glacial forcing

    Science.gov (United States)

    Cordier, Stéphane; Adamson, Kathryn; Delmas, Magali; Calvet, Marc; Harmand, Dominique

    2017-06-01

    Much research, especially within the framework of the Fluvial Archives Group, has focused on river response to climate change in mid-latitude non-glaciated areas, but research into the relationships between Quaternary glacial and fluvial dynamics remains sparse. Understanding glacial-fluvial interactions is important because glaciers are able to influence river behaviour significantly, especially during glacial and deglacial periods: (1) when they are located downstream of a pre-existing fluvial system and disrupt its activity, leading to hydrographical, hydrosedimentary and isostatic adjustments, and (2) when they are located upstream, which is a common scenario in mid-latitude mountains that were glaciated during Pleistocene cold periods. In these instances, glaciers are major water and sediment sources. Their role is particularly significant during deglaciation, when meltwater transfer towards the fluvial system is greatly increased while downstream sediment evacuation is influenced by changes to glacial-fluvial connectivity and basin-wide sediment storage. This means that discharge and sediment flux do not always respond simultaneously, which can lead to complex fluvial behaviour involving proglacial erosion and sedimentation and longer-term paraglacial reworking. These processes may vary spatially and temporally according to the position relative to the ice margin (ice-proximal versus ice-distal). With a focus on the catchments of Europe, this paper aims to review our understanding of glacial impacts on riversystem behaviour. We examine the methods used to unravel fluvial response to 'glacial forcing', and propose a synthesis of the behaviour of glacially-fed rivers, opening perspectives for further research.

  7. Control of Quaternary sea-level changes on gas seeps

    Science.gov (United States)

    Riboulot, Vincent; Thomas, Yannick; Berné, Serge; Jouet, Gwénaël.; Cattaneo, Antonio

    2014-07-01

    Gas seeping to the seafloor through structures such as pockmarks may contribute significantly to the enrichment of atmospheric greenhouse gases and global warming. Gas seeps in the Gulf of Lions, Western Mediterranean, are cyclical, and pockmark "life" is governed both by sediment accumulation on the continental margin and Quaternary climate changes. Three-dimensional seismic data, correlated to multi-proxy analysis of a deep borehole, have shown that these pockmarks are associated with oblique chimneys. The prograding chimney geometry demonstrates the syn-sedimentary and long-lasting functioning of the gas seeps. Gas chimneys have reworked chronologically constrained stratigraphic units and have functioned episodically, with maximum activity around sea level lowstands. Therefore, we argue that one of the main driving mechanisms responsible for their formation is the variation in hydrostatic pressure driven by relative sea level changes.

  8. The geological characteristics during the quaternary period around Japan island

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Shigeru [Chuo Kaihatsu Corp., Enterprises Promotion Bureau, Tokyo (Japan); Sakamoto, Yoshiaki; Ogawa, Hiromichi; Nakayama, Shinichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    Radioactive wastes arising from radioisotope facilities and nuclear research facilities should be disposed of in the surface of the earth, the shallow underground, the adequate depth and the deep underground according to radioactivity concentrations, and should be managed during several hundreds years. The earth scientific phenomena observed in Japan island at present occurred continuously from the past, and the same phenomena at the future should occur in the similar factor. Therefore, for the purpose to get the fundamental data for the selection of disposal site, this report reviewed on the genesis and classification of the sediments, earth scientific phenomena observed in Japan island and the feature of each place (10 districts) concerning to the Quaternary period in the newest geological time unit. (author)

  9. Mineralogy and Surface Composition of Asteroids

    CERN Document Server

    Reddy, Vishnu; Thomas, Cristina A; Moskovitz, Nicholas A; Burbine, Thomas H

    2015-01-01

    Methods to constrain the surface mineralogy of asteroids have seen considerable development during the last decade with advancement in laboratory spectral calibrations and validation of our interpretive methodologies by spacecraft rendezvous missions. This has enabled the accurate identification of several meteorite parent bodies in the main asteroid belt and helped constrain the mineral chemistries and abundances in ordinary chondrites and basaltic achondrites. With better quantification of spectral effects due to temperature, phase angle, and grain size, systematic discrepancies due to non-compositional factors can now be virtually eliminated for mafic silicate-bearing asteroids. Interpretation of spectrally featureless asteroids remains a challenge. This paper presents a review of all mineralogical interpretive tools currently in use and outlines procedures for their application.

  10. Mineralogical Evolution in Extreme Debris Disks

    Science.gov (United States)

    Su, Kate

    2015-10-01

    Young (10-200 Myr), luminous (fractional luminosity on the order of 1.E-2) extreme debris disks provide a unique opportunity to explore exo-asteriod and exo-planetesimal collisions during the oligarchic and chaotic phases of terrestrial planet-building. We propose to obtain low-resolution grism spectra of four extreme debris disks to document and characterize the mineralogy changes in the mid-IR region where strong peaks originating from silica and forsterite dust can be easily identified. The proposed observations will supplement our on-going warm Spitzer monitoring program studying disk variability at 3.6 and 4.5 microns, provide immediate insights on the long-term mineralogical evolution in comparison with the existing Spitzer IRS spectra, and will bridge to similar studies that JWST will provide in the near future.

  11. An unpublished text of Jovellanos about mineralogy

    Directory of Open Access Journals (Sweden)

    Jorge ORDAZ GARGALLO

    2012-02-01

    Full Text Available An unpublished manuscript of Gaspar Melchor de Jovellanos about the history of mineralogy, written during his captivity in Bellver Castle (Palma de Mallorca is presented and analyzed. In this writing the importance of the chemical knowledge as a source of other branches of science and its applications in different fields of agriculture, mining and industry is considered. The author made a historical synthesis reviewing the men of science that contributed in a great extent to the advance of the chemistry and mineralogy. The text clearly supports the new contributions of Lavoisier and other supporters of experimentation as a scientific method, which agrees with Jovellanos’ ideas about the development of the «useful» sciences for the progress of the countries.

  12. Late Quaternary changes in climate

    Energy Technology Data Exchange (ETDEWEB)

    Holmgren, K.; Karlen, W. [Stockholm Univ. (Sweden). Dept. of Physical Geography

    1998-12-01

    This review concerns the Quaternary climate with an emphasis on the last 200 000 years. The present state of art in this field is described and evaluated. The review builds on a thorough examination of classic and recent literature. General as well as detailed patterns in climate are described and the forcing factors and feed-back effects are discussed. Changes in climate occur on all time-scales. During more than 90% of the Quaternary period earth has experienced vast ice sheets, i.e. glaciations have been more normal for the period than the warm interglacial conditions we face today. Major changes in climate, such as the 100 000 years glacial/interglacial cycle, are forced by the Milankovitch three astronomical cycles. Because the cycles have different length climate changes on earth do not follow a simple pattern and it is not possible to find perfect analogues of a certain period in the geological record. Recent discoveries include the observation that major changes in climate seem to occur at the same time on both hemispheres, although the astronomical theory implies a time-lag between latitudes. This probably reflects the influence of feed-back effects within the climate system. Another recent finding of importance is the rapid fluctuations that seem to be a normal process. When earth warmed after the last glaciation temperature jumps of up to 10 deg C occurred within less than a decade and precipitation more than doubled within the same time. The forcing factors behind these rapid fluctuations are not well understood but are believed to be a result of major re-organisations in the oceanic circulation. Realizing that nature, on its own, can cause rapid climate changes of this magnitude put some perspective on the anthropogenic global warming debate, where it is believed that the release of greenhouse gases will result in a global warming of a few C. To understand the forcing behind natural rapid climate changes appears as important as to understand the role

  13. An unpublished text of Jovellanos about mineralogy

    OpenAIRE

    Ordaz Gargallo, Jorge; Gutiérrez Claverol, Manuel; De Lorenzo Álvarez, Elena

    2012-01-01

    An unpublished manuscript of Gaspar Melchor de Jovellanos about the history of mineralogy, written during his captivity in Bellver Castle (Palma de Mallorca) is presented and analyzed. In this writing the importance of the chemical knowledge as a source of other branches of science and its applications in different fields of agriculture, mining and industry is considered. The author made a historical synthesis reviewing the men of science that contributed in a great extent to the advance of t...

  14. Talc pneumoconiosis: a pathologic and mineralogic study.

    Science.gov (United States)

    Gibbs, A E; Pooley, F D; Griffiths, D M; Mitha, R; Craighead, J E; Ruttner, J R

    1992-12-01

    Seventeen cases of "talc pneumoconiosis" were examined pathologically and mineralogically to ascertain whether a true talc pneumoconiosis existed and also to compare these results in primary, secondary, and tertiary exposures. Mineralogic analyses were performed on wet tissue or tissue blocks by a variety of techniques, including analytical transmission electron microscopy and x-ray diffraction. Overall, the pathologic appearance of the tissues was similar in primary, secondary, and tertiary exposures, although ferruginous bodies and foreign body giant cells were not always present in cases caused by secondary exposures. Mixed dust fibrotic lesions were found in two cases in which there were substantial quantities of quartz present. There was great variation in the minerals found within the lung tissues. Several cases showed significant quantities of mica and kaolin in addition to talc. One case consisted predominantly of mica and in fact could be regarded as "mica pneumoconiosis"; this diagnosis was correctly attributed because of the mineralogic findings. Tremolite fibers were found in only two cases. Substantial quantities of crocidolite and amosite fibers were found in one case. This study shows that "talcosis" frequently represents disease associated with a variety of minerals and that talc is a common denominator. It shows also the usefulness of lung dust mineral analysis, particularly in secondary industries, for evaluating the cause of a pathologic reaction when exposures are especially complex.

  15. Arsenic concentrations in soils and sediments of the southern Pampean Plain, within Claromecó River Basin (Argentina)

    Science.gov (United States)

    Sosa, N. N.; Datta, S.; Zarate, M.

    2015-12-01

    The Pampean plain is an extensive flatland covering ~1000000 km2 of central and northern Argentina. The region, dominated by Neogene and quaternary volcanoclastic loess and loess-like deposits, shows one of the highest groundwater As concentrations of the world which cause serious problems to human health. The oxidising and high pH conditions of the Pampean groundwater leads to the dissolution of volcanic glass and Fe oxy-hydroxides and the release of As to water. Variation of As content related to lithogenic factors is evident from our study in Claromecó River Basin (Southern Pampean plain): the Mio-Pliocene fluvial facies (MPFF) show low As content (2.6mg/kg) compared to the Late Pleistocene fluvial facies (11.6mg/kg; LPFF). Furthermore, the pedogenic calcrete and the paleosols developed in fluvial facies present significantly different As content: 3.9 mg/Kg in MPFF pedogenic calcrete and 16.5 mg/Kg in LPFF paleosols. Modern soils show the highest As content, especially in the illuvial horizons (23.3 mg/Kg) controlled by grain size and clay mineralogy constituents. Preliminary results demonstrate a sedimentological control embarking differences in As concentrations. These differences are probably attributed to a major hydraulic gradient during the MPFF, which is reflected in grain size and in fluvial structures, which probably was followed by washed out sediments. A geomorphological control was observed through an increase of As concentrations from the interfluves (MPFF) to the valleys (LPFF) as well as from the upper to the lower basin zone within the LPFF. Pedogenic calcrete and paleosols developed in MPFF and LPFF respectively reflect the different geomorphological conditions showing high As content in LPFF paleosols (attributed to Fe oxy-hydroxides). This study relates mineralogy and sedimentological environment to groundwater, surface water from wetlands to understand the hydrochemical processes in controlling As within the Claromecó basin.

  16. Mineralogical discrimination of the pleistocene loess/paleosol sections in Srijem and Baranja, Croatia

    Science.gov (United States)

    Galović, Lidija; Peh, Zoran

    2016-06-01

    Previous investigations of the mineralogical composition of loess sections (loess, loess-like sediments, paleosols, alluvial intercalations) in the Carpathian Basin have concluded that the Danube River is the dominant control on the loessitic parent material. These investigations also identify a significant role for the Danube's tributaries in creating local variations. The north-south alignment of these sections forms a transect from the central part of the Carpathian Basin to its southern edge. In this work, the mineral origin of loess sediments was identified by using the multivariate statistical method of discriminant function analysis. Two models were constructed based on the modal composition as the suite of predictor (independent) variables: one is using geographic location as the a priori grouping criterion (SECTION); another employing the difference between the sampling media (LITHOLOGY). Both of the examined discriminant models demonstrate the existence of the mixing zones. The Erdut section is a clear mixture of the mineralogies at the other studied locations, while loesses appear generally intermediate in mineralogy between alluvium and paleosol. The main rationale for the observed difference in modal composition between the Šarengrad and other analyzed sections is the proximity of the Šarengrad section to the Sava River floodplain and Dinaric Ophiolite Zone (DOZ), both important source areas for aeolian sediments in the southern edge of the Carpathian Basin that transport material from the Central Bosnian Mountains unit of DOZ. Chemically, the most resistant heavy minerals together with opaque minerals are exclusively associated with paleosols, being typical products of geochemical pedogenic processes.

  17. Ferricretes of the Early Tertiary Dammam Formation in the Dukhan Area, Western Qatar: mineralogy, geochemistry, and environment of deposition

    OpenAIRE

    Nasir, Sobhi J. [صبحي جابر نصر; Al-Saad, Hamad; Al-Sayigh, Abdul Razak; Al-Harthy, Abdul Rahman; Almishwat, Ali; Dill, Harald

    2003-01-01

    Ferricretes of the Middle Eocene Dammam Formation, Western Qatar, were investigated using petrographic and ore microscopy, IR TGA, XRD, and geochemical analyses. The ferricretes mainly consist of goethite, which is very varigated in habit and texture. Geochemical analyses show that the ferricretes consist of impure chemical sediments, iron hydroxides plus variable amounts of carbonate and siliciclastic materials. The ferricretes resemble with respect to texture, mineralogy and chemistry mo...

  18. Mineralogical, geochemical and hydrocarbon potential of subsurface Cretaceous shales, Northern Western Desert, Egypt

    Directory of Open Access Journals (Sweden)

    D.A. Mousa

    2014-03-01

    Full Text Available Twenty four Cretaceous shale core samples of Gibb Afia-1, Betty-1, Salam-1X and Mersa Matruh-1 wells were mineralogically and geochemically studied using XRD, XRF and Rock Eval Pyrolysis. Kaolinite, smectite and illite are the main clay minerals in addition to rare chlorite, while the non-clay minerals include quartz, calcite, dolomite and rare siderite. The shales were derived through intensive chemical weathering of mafic basement and older sedimentary rocks. These sediments were deposited in a near-shore shallow marine environment with some terrestrial material input. The shales have poor to fair organic content. It is marginally to rarely mature.

  19. Soil mineralogy and chemistry on Mars - Possible clues from salts and clays in SNC meteorites

    Science.gov (United States)

    Gooding, James L.

    1992-01-01

    If the shergottite, nakhlite, and chassignite (SNC) meteorites' parent planet is Mars, then the aqueous precipitates found in them imply that oxidizing, water-based solutions may have been chemically active on that planet over the past 200-1300 million yrs. It is suggested that the mixture of aqueous precipitates found in the SNCs furnish a self-consistent model for the bulk elemental composition of surface sediments at the Viking Lander sites. Further mineralogical and stable-isotope studies of the secondary minerals may establish the limits for biological activity over the last 1300 million years of Mars' water-based chemistry.

  20. A New Method to Identify Quaternary Moraine:Acoustic Emission Stress Measurement

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhizhong; QIAO Yansong; TIAN Jiaorong; WANG Min; LI Mingze; HE Peiyuan; QIAN Fang

    2006-01-01

    How to effectively identify glacial sediments, especially Quaternary moraine, has been in dispute for decades. The traditional methods, e.g., sedimentary and geomorphologic ones, are facing challenge in eastern China where controversial moraine deposits are dominatingly distributed. Here,for the first time, we introduce the acoustic emission (AE) stress measurement, a kind of historical stress measurement, to identify Quaternary moraine. The results demonstrate that it can be employed to reconstruct stress information of glaciation remaining in gravels, and may shed light on the identification of Quaternary moraine in eastern China. First, we measured the AE stress of gravels of glacial origin that are underlying the Xidatan Glacier, eastern Kunlun Mountains in western China.Second, we calculated the stress according to the actual thickness of the glacier. The almost identical stress values suggest that the glacial gravels can memorize and preserve the overlying glacier-derived aplomb stress. And then we introduce this new approach to the controversial moraine in Mount Lushan, eastern China. The results indicate that the stress is attributed to the Quaternary glacier, and the muddy gravels in the controversial moraine in Mount Lushan are moraine deposits but not others.

  1. Paleovalley systems: Insights from Quaternary analogs and experiments

    Science.gov (United States)

    Blum, M.; Martin, J.; Milliken, K.; Garvin, M.

    2013-01-01

    Ancient fluvial valley systems are long recognized as important features in the stratigraphic record, but emerged as a specific focus of attention with publication of first-generation sequence-stratigraphic concepts. This paper reviews current understanding of paleovalley systems from the perspective of Quaternary analogs and experimental studies. Paleovalley systems can include distinct mixed bedrock-alluvial, coastal-plain, and cross-shelf segments. Mixed bedrock-alluvial segments are long-lived, cut across bedrock of significantly older age, and have an overall degradational architecture. By contrast, coastal-plain and cross-shelf segments are non-equilibrium responses to high-frequency cycles of relative sea-level change: most coastal-plain and cross-shelf segments form as a geometric response to relative sea-level fall, as river systems cut through coastal-plain and inner shelf clinothems, and extend basinward to track the shoreline. After incision and cross-shelf extension, lateral channel migration and contemporaneous channel-belt deposition creates a valley-scale feature. Coastal-plain and cross-shelf paleovalley widths are set by the number of channel-belt sandbodies deposited during this time. Paleovalley systems play a key role in source-to-sink sediment routing. Early views included the model of incision and complete sediment bypass in response to relative sea-level fall. However, this model does not stand up to empirical, theoretical, or experimental scrutiny. Instead, there is a complex dynamic between incision, deposition, and sediment export from an evolving valley: periods of incision correspond with sediment export minima, whereas periods of lateral migration and channel-belt construction result in increased flux to the river mouth. Sediment export from evolving valleys, and merging of drainages during cross-shelf transit, play key roles in sediment transfer to the shelf-margin and genetically-linked slope to basin-floor systems. Connection

  2. Corrosion mineralogy of an 1800 Spanish piece of eight

    Energy Technology Data Exchange (ETDEWEB)

    Craig, J.R. [Virginia Polytechnic Inst. and State Univ., Dept. of Geological Sciences, Blacksburg, Virginia (United States); Callahan, J.E. [Appalachain State Univ., Dept. of Geology, Boone, North Carolina (United States); Kimbell, J.T. [Tavernier, Florida (United States); Solberg, T.N. [Virginia Polytechnic Inst. and State Univ., Dept. of Geological Sciences, Blacksburg, Virginia (United States)

    2002-04-01

    Spanish colonial eight real silver coins, commonly called Pieces of Eight, were used throughout the Spanish-speaking world for hundreds of years. We undertook a detailed mineralogical, textural, and chemical investigation of an 1800 Carlos IIII eight real coin recovered from the wreck of the Spanish frigate Santa Leocadia, which sank on the rocky shore of Ecuador on November 16, 1800, with a loss of more than 140 lives and of 2,100,000 pesos of gold and silver coins. The coin is a typical eight real piece, composed of about 90% Ag and 10% Cu. It was buried in elastic sediments beneath the oxidized zone, such that it reacted with sulfur released by sulfate-reducing bacteria. Consequently, the coin has been totally encapsulated in a mixture of sand, gravel, and shell fragments cemented by metal sulfides. The residual coin consists of silver with small interspersed micrometric grains of copper. Reaction of the dissolved metal with the bacterially generated diagenetic sulfur in the intergranular fluids resulted in extensive cementation of the sediment particles by Ag and Cu sulfides. In the 1-mm zone immediately adjacent to the coin, Cu-bearing acanthite occurs as concentric layers with intervening zones of sand and clay. Beyond this zone, acanthite formed from Ag dissolved from the coin occurs as a more or less continuous interstitial cement with local small islands of covellite, CuS. Copper also occurs as films of Cu carbonate on quartz grains, as isolated grains of jalpaite Ag{sub 3}CuS{sub 2}, stromeyerite AgCuS, mckinstryite (Ag,Cu){sub 2}S, and as atacamite Cu{sub 2}C1(OH){sub 3}, which rim and replace detrital carbonate grains. (author)

  3. Chemical, Mineralogical, and Physical Properties of Martian Dust and Soil

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2017-01-01

    Global and regional dust storms on Mars have been observed from Earth-based telescopes, Mars orbiters, and surface rovers and landers. Dust storms can be global and regional. Dust is material that is suspended into the atmosphere by winds and has a particle size of 1-3 micrometer. Planetary scientist refer to loose unconsolidated materials at the surface as "soil." The term ''soil'' is used here to denote any loose, unconsolidated material that can be distinguished from rocks, bedrock, or strongly cohesive sediments. No implication for the presence or absence of organic materials or living matter is intended. Soil contains local and regional materials mixed with the globally distributed dust by aeolian processes. Loose, unconsolidated surface materials (dust and soil) may pose challenges for human exploration on Mars. Dust will no doubt adhere to spacesuits, vehicles, habitats, and other surface systems. What will be the impacts on human activity? The objective of this paper is to review the chemical, mineralogical, and physical properties of the martian dust and soil.

  4. Mineralogical and Geochemical Trends in a Fluviolacustrine Sequence in Gale Crater, Mars

    Science.gov (United States)

    Rampe, E.; Ming, D.; Morris, R.; Blake, D.; Vaniman, D.; Bristow, T.; Chipera, S.; Yen, A.; Grotzinger, J.; DesMarais, D.

    2016-01-01

    The Mars Science Laboratory rover, Curiosity, landed at Gale crater in August 2012 and has been investigating a sequence of dominantly fluviolacustrine sediments deposited 3.6-3.2 billion years ago. Curiosity collects quantitative mineralogical data with the CheMin XRD/XRF instrument and quantitative chemical data with the APXS and ChemCam instruments. These datasets show stratigraphic mineralogical and geochemical variability that suggest a complex aqueous history. The Murray Formation, primarily composed of fine-laminated mudstone, has been studied in detail since the arrival at the Pahrump Hills in September 2014. CheMin data from four samples show variable amounts of iron oxides, phyllosilicates, sulfates, amorphous and crystalline silica, and mafic silicate minerals. Geochemical data throughout the section show that there is significant variability in Zn, Ni, and Mn concentrations. Mineralogical and geochemical trends with stratigraphy suggest one of possibly several aqueous episodes involved alteration in an open system under acidic pH, though other working hypotheses may explain these and other trends. Data from the Murray Formation contrast with those collected from the Sheepbed mudstone located approximately 60 meters below the base of the Murray Formation, which showed evidence for diagenesis in a closed system at circumneutral pH. Ca-sulfates filled late-stage veins in both mudstones.

  5. Micropaleontologic record of Quaternary paleoenvironments in the Central Albemarle Embayment, North Carolina, U.S.A.

    Science.gov (United States)

    Culver, Stephen J.; Farrell, Kathleen M.; Mallinson, David J.; Willard, Debra A.; Horton, Benjamin P.; Riggs, Stanley R.; Thieler, E. Robert; Wehmiller, John F.; Parham, Peter; Snyder, Scott W.; Hillier, Caroline

    2011-01-01

    To understand the temporal and spatial variation of eustatic sea-level fluctuations, glacio-hydro-isostacy, tectonics, subsidence, geologic environments and sedimentation patterns for the Quaternary of a passive continental margin, a nearly complete stratigraphic record that is fully integrated with a three dimensional chronostratigraphic framework, and paleoenvironmental information are necessary. The Albemarle Embayment, a Cenozoic regional depositional basin in eastern North Carolina located on the southeast Atlantic coast of the USA, is an ideal setting to unravel these dynamic, interrelated processes.Micropaleontological data, coupled with sedimentologic, chronostratigraphic and seismic data provide the bases for detailed interpretations of paleoenvironmental evolution and paleoclimates in the 90. m thick Quaternary record of the Albemarle Embayment. The data presented here come from a transect of cores drilled through a barrier island complex in the central Albemarle Embayment. This area sits in a ramp-like setting between late Pleistocene incised valleys.The data document the episodic infilling of the Albemarle Embayment throughout the Quaternary as a series of transgressive-regressive (T-R) cycles, characterized by inner shelf, midshelf, and shoreface assemblages, that overlie remnants of fluvial to estuarine valley-fill. Barrier island and marginal marine deposits have a low preservation potential. Inner to mid-shelf deposits of the early Pleistocene are overlain by similar middle Pleistocene shelf sediments in the south of the study area but entirely by inner shelf deposits in the north. Late Pleistocene marine sediments are of inner shelf origin and Holocene deposits are marginal marine in nature. Pleistocene marine sediments are incised, particularly in the northern half of the embayment by lowstand paleovalleys, partly filled by fluvial/floodplain deposits and in some cases, overlain by remnants of transgressive estuarine sediments. The shallowing

  6. Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman

    Science.gov (United States)

    Blechschmidt, Ingo; Matter, Albert; Preusser, Frank; Rieke-Zapp, Dirk

    2009-09-01

    A vast bajada consisting of coalescing low-gradient (veneer of weakly cemented Quaternary gravels. A combination of remote sensing, lithological analyses and luminescence dating is used to interpret the complex aggradation history of the Quaternary alluvial fans from the interior of Oman in the context of independent regional climate records. From satellite imagery and clast analysis four fans can be discerned in the study area. While two early periods of fan formation are tentatively correlated to the Miocene-Pliocene and the Early Pleistocene, luminescence dating allows the distinction of five phases of fan aggradation during the Middle-Late Pleistocene. These phases are correlated with pluvial periods from Marine Isotope Stage (MIS) 11 through 3, when southern Arabia was affected by monsoonal precipitation. It is concluded that the aggradation of the alluvial fans was triggered by the interplay of increased sediment production during arid periods and high rainfall with enhanced erosion of hillslopes and transport rates during strong monsoon phases. However, the lack of fine-grained sediments, bioturbation and organic material implies that although the Quaternary fans are sourced by monsoonal rains they formed in a semi-arid environment. Thus, it appears that, in contrast to the Oman Mountains, the interior was not directly affected by monsoonal precipitation.

  7. Quaternary fluvial response to climate change in glacially influenced river systems

    Science.gov (United States)

    Cordier, Stéphane; Adamson, Kathryn; Delmas, Magali; Calvet, Marc; Harmand, Dominique

    2016-04-01

    Over the last few decades, many studies in Europe and other continents have focused on the fluvial response to climate forcing in unglaciated basins. However, glacial activity may have a profound impact on the behaviour of the fluvial systems located downstream. In comparison to ice-free basins, these systems are characterised by distinctive hydrological and sediment supply regimes. Over Quaternary timescales, the fluvial records are influenced by periglacial (in non-glaciated areas), proglacial, and paraglacial processes. Understanding the impacts of these processes on the formation and preservation of the Quaternary geomorphological and sedimentary archives is key for our understanding of glacial-fluvial interactions. We investigate the impact of Quaternary glacial activity on fluvial sediment transfer, deposition, and preservation. Using existing studies from across Europe, we create a database of glaciofluvial geomorphology, sedimentology, and geochronology. This is used to examine how glacial forcing of fluvial systems varies spatially in different basin settings, and temporally over successive Milankovitch cycles. In particular, we focus on the ways in which the primary glacial-fluvial depositional signal could be distinguished from periglacial and paraglacial reworking and redeposition.

  8. A model of the Quaternary geological deposits of Bucharest City

    Science.gov (United States)

    Serpescu, Irina; Radu, Emil; Radu Gogu, Constantin; Amine Boukhemacha, Mohamed; Gaitanaru, Dragos; Bica, Ioan

    2013-04-01

    Bucharest city is located in the central part of the Moesic Platform, in the Romanian Plain with micro-relief resulting from erosion and sedimentary processes which extended along the valleys of the Dambovita River to the south and the Colentina River to the north. The city is located in the axial area of a syncline where the thickness of the sedimentary deposits is up to 1000 m. The area lies on a rigid base is made of metamorphites, and various igneous intrusions (granodiorite, granite). The sedimentary deposits covering this rigid base are made by different phases of erosion and sedimentary processes of marine, lacustrian or continental sediments ending with Quaternary sediments. As a result, different alluvial deposits (such as piedmont, deltaic, alluvial cones, terrace, waterside and lacustrine deposits) can be met. Furthermore one also can find loess deposits which in turn cover totally the older deposits where rivers dug the present relief. To highlight the spatial extent of these geological structures, a geological model of Bucharest city is developed. A set of information coming from different sources as geological and geotechnical boreholes showing a detailed geological and lithological description, geological and topographical maps, geological and hydrogeological reports have been used to develop the 3D geological model of this region. 33 geological cross sections were defined and interpreted by using lithological and sedimentological criteria. Using these geological cross sections and prior geological knowledge, the Quaternary deposits have been described and classified into 6 structural units given from top to down as follows: (1) Superficial deposits represented by loess and anthropogenic materials. The geological model indicates that these deposits show a sporadic development becoming more concentrated in the central west part of the city. (2) Colentina Formations composed by of poorly sorted, cross-stratified sand and gravel with clayey lens

  9. Consolidation and strength properties of calcareous sediments from Kaneohe and Kailua Bays, Hawaii

    Digital Repository Service at National Institute of Oceanography (India)

    Brandes, H.G.; Khadge, N; Nakayama, D.D

    -carbonate sediments do not seem to have a large effect on consolidation and triaxial behavior. Due to contrasting mineralogies between the land-derived volcanic soils and the calcareous sediment of marine origin, carbonate content is a useful property that serves...

  10. Paleo-redox fronts and their formation in carbonate mound sediments from the Rockall Trough

    NARCIS (Netherlands)

    van der Land, C.; Mienis, F.; de Haas, H.; de Stigter, H.C.; Swennen, R.; Reijmer, J.J.G.; van Weering, T.C.E.

    2011-01-01

    Piston cores from the summits of coral topped carbonate mounds at the south west Rockall Trough margin reveal that the sediments have undergone significant post-depositional modifications affecting the original geochemical signature and mineralogical composition of the sediments. This diagenetic imp

  11. PRN 88-2: Clustering of Quaternary Ammonium Compounds

    Science.gov (United States)

    This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds

  12. Sedimentary sources and processes in the eastern Arabian Sea: Insights from environmental magnetism, geochemistry and clay mineralogy

    Directory of Open Access Journals (Sweden)

    Kumar Avinash

    2016-03-01

    Full Text Available The spatial distribution patterns of surficial sediment samples from different sedimentary domains (shallow to deep-sea regions of the eastern Arabian Sea were studied using sediment proxies viz. environmental magnetism, geochemistry, particle size and clay mineralogy. Higher concentrations of magnetic minerals (high χlf were recorded in the deep-water sediments when compared with the shallow water sediments. The magnetic mineralogy of one of the shallow water samples is influenced by the presence of bacterial magnetite as evidenced from the χARM/χlf vs. χARM/χfd biplot. However, the other samples are catchment-derived. The high correlation documented for χlf, anhysteretic remanent magnetisation (χARM and isothermal remanent magnetisation (IRM with Al indicates that the deep-sea surficial sediments are influenced by terrigenous fluxes which have been probably derived from the southern Indian rivers, the Sindhu (the Indus and the Narmada-Tapti rivers. A lower Mn concentration is recorded in the upper slope sediments from the oxygen minimum zone (OMZ but a higher Mn/Al ratio is documented in the lower slope and deep-sea sediments. Clay minerals such as illite (24–48.5%, chlorite (14.1–34.9%, smectite (10.6–28.7% and kaolinite (11.9–27.5% dominate the sediments of shallow and deep-sea regions and may have been derived from different sources and transported by fluvial and aeolian agents. Organic carbon (OC data indicate a low concentration in the shallow/shelf region (well oxygenated water conditions and deeper basins (increased bottom-water oxygen concentration and low sedimentation rate. High OC concentrations were documented in the OMZ (very low bottom-water oxygen concentration with high sedimentation rate. The calcium carbonate concentration of the surface sediments from the continental shelf and slope regions (<1800 m up to the Chagos-Laccadive Ridge show higher concentrations (average = 58% when compared to deep basin

  13. Catalytic enantioselective synthesis of quaternary carbon stereocentres

    Science.gov (United States)

    Quasdorf, Kyle W.; Overman, Larry E.

    2014-12-01

    Quaternary carbon stereocentres--carbon atoms to which four distinct carbon substituents are attached--are common features of molecules found in nature. However, before recent advances in chemical catalysis, there were few methods of constructing single stereoisomers of this important structural motif. Here we discuss the many catalytic enantioselective reactions developed during the past decade for the synthesis of single stereoisomers of such organic molecules. This progress now makes it possible to incorporate quaternary stereocentres selectively in many organic molecules that are useful in medicine, agriculture and potentially other areas such as flavouring, fragrances and materials.

  14. Climate predictors of late quaternary extinctions

    DEFF Research Database (Denmark)

    Nogués-Bravo, David; Ohlemüller, Ralf; Batra, Persaram

    2010-01-01

    Between 50,000 and 3,000 years before present (BP) 65% of mammal genera weighing over 44 kg went extinct, together with a lower proportion of small mammals. Why species went extinct in such large numbers is hotly debated. One of the arguments proposes that climate changes underlie Late Quaternary...... extinctions, but global quantitative evidence for this hypothesis is still lacking. We test the potential role of global climate change on the extinction of mammals during the Late Quaternary. Our results suggest that continents with the highest climate footprint values, in other words, with climate changes...

  15. Chromite Enrichment in the Recent Fluviatile Sediments, North Iraq

    OpenAIRE

    Al Juboury, Ali I. [علي الجبوري; Ismail, Sabah A.; Ghazal, Mohsin M.

    1999-01-01

    The Recent sediments from North Iraq are characterized by a higher content of chromite. This paper deals with the mineralogy and geochemistry of chromite in the heavy mineral assemblages from Recent fluvial sediments in an attempt to elucidate its distribution and source rock. The heavy fraction is composed of iron oxides and chromite forming about 50% of the total heavies. Chromite forms up to 80% of the opaque minerals at some areas in North Iraq. The non-opaque heavy minerals are composed ...

  16. 21 CFR 172.165 - Quaternary ammonium chloride combination.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Quaternary ammonium chloride combination. 172.165... HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food additive, quaternary ammonium chloride combination, may be safely used in food in accordance with...

  17. Significance of Quaternary and Experimental Fluvial Systems to Interpretation of the Stratigraphic Record

    Science.gov (United States)

    Blum, M. D.; Martin, J. M.

    2012-12-01

    Studies of Quaternary and experimental fluvial systems provide significant insight for interpretation of fluvial deposits in the stratigraphic record, ranging from measurement of processes and relevant scales of key architectural elements, to process-based understanding of fluvial systems in sequence stratigraphic models. One key advantage for Quaternary and experimental systems is they commonly provide the ability to test, in a classical verification or falsification sense, interpretations, models and their alternatives that were developed from the stratigraphic record alone. First, scaling relationships developed from Quaternary fluvial deposits can be utilized to constrain interpretations of ancient strata, as well as predict the scale of channel fills, channel-belt sand bodies, and incised valleys. Scaling relationships are defined by power laws, with absolute dimensions that scale to drainage area, water flux, and sediment flux. Width-to-thickness ratios for channel fills range from 10-20:1, whereas channel-belt sand bodies upstream from backwater effects commonly range from 70-300:1, and 20-40:1within the backwater zone, where channel migration is limited. Quaternary incised valleys range from 25-150 m in thickness, and ~5-100 km in width, with width-to-thickness ratios of ~500-800. Scales of Quaternary channel fills and channel-belt sand bodies overlap are consistent with compilations from the ancient record. However, even the smallest Quaternary incised valleys reside in the uppermost part of the domain of published ancient valleys, with ancient examples overlapping significantly with modern channel fills and channel belts. We suggest that many ancient examples have been overinterpreted because of a lack of objective criteria for differentiating channel fills, channel belts, and incised valleys. Second, incised valleys have long played a key role in sequence-stratigraphic interpretations. For incised valleys in the stratigraphic record, either in outcrop or

  18. Astronomical tuning of long pollen records reveals the dynamic history of montane biomes and lake levels in the tropical high Andes during the Quaternary

    NARCIS (Netherlands)

    Torres, V.; Hooghiemstra, H.; Lourens, L.; Tzedakis, P.C.

    2013-01-01

    Long pollen records from two sediment cores of the basin of Bogotá (Colombia) are presented, reflecting the dynamic history of environmental and vegetation changes in the tropical high Andes during the Quaternary. An astronomically tuned age model has been developed by using the visual correlation

  19. Understanding the major transitions in Quaternary climate dynamics

    Science.gov (United States)

    Willeit, Matteo; Ganopolski, Andrey

    2017-04-01

    Climate dynamics over the past 3 million years was characterized by strong variability associated with glacial cycles and several distinct regime changes. The Pliocene-Pleistocene Transition (PPT), which happened around 2.7 million years ago, was characterized by the appearance of the large continental ice sheets over Northern Eurasia and North America. For two million years after the PPT climate variability was dominated by relatively symmetric 40 kyr cycles. At around 1 million years ago the dominant mode of climate variability experienced a relatively rapid transition from 40 kyr to strongly asymmetric 100 kyr cycles of larger amplitude (Mid-Pleistocene Transition). Additionally, during the past 800 kyr there are clear differences between the earlier and the later glacial cycles with the last five cycles characterized by larger magnitude of variability (Mid-Brunhes Event). Here, we use the Earth system model of intermediate complexity CLIMBER-2 to explore possible mechanisms that could explain these regime shifts. CLIMBER-2 incorporates all major components of the Earth system - atmosphere, ocean, land surface, northern hemisphere ice sheets, terrestrial biota and soil carbon, marine biogeochemistry and aeolian dust. The model was optimally tuned to reproduce climate, ice volume and CO2 variability over the last 400,000 years. Using the same model version, we performed a large set of simulations covering the entire Quaternary (3 million years) starting from identical initial conditions and using a parallelization in time technique which consists of starting the model at different times (every 100,000 years) and running each simulation for 500,000 years. The Earth's orbital variations are the only prescribed radiative forcing. Several sets of the Northern Hemisphere orography and sediment thickness representing different stages of landscape evolution during the Quaternary are prescribed as boundary conditions for the ice sheet model and volcanic CO2 outgassing is

  20. Topographical mineralogy of the Bamble sector, south Norway

    NARCIS (Netherlands)

    Nijland, T.G.; Zwaan, J.C.; Touret, L.

    1998-01-01

    The Bamble sector of southern Norway is a classic high grade metamorphic gneiss region, which provided specimens to many mineralogical collections all over the world. The topographical mineralogy of this area is described and reviewed. All minerals known to occur in the area are listed according to

  1. Mapping the North Sea base-Quaternary: using 3D seismic to fill a gap in the geological record

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    The identification and mapping of the base-Quaternary boundary in the central parts of the North Sea is problematic due to the change from an unconformable transition between Pliocene and Pleistocene deltaic deposits in the southern North Sea to a conformable one further north (Sejrup et al 1991; Gatliff et al 1994). The best estimates of the transition use seismic reflection data to identify a 'crenulated reflector' (Buckley 2012), or rely on correlating sparse biostratigraphy (Cameron et al 1987). Recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) allows greater confidence in the correlation to a regional 3D seismic dataset and show that the base-Quaternary can be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The mapped horizon is presented here alongside the difference between this new interpretation and the previously interpreted base-Quaternary (Buckley 2012). The revised base-Quaternary surface reaches a depth of 1248 ms TWT or approximately 1120 m (assuming average velocity of 1800 m/s) showing an elongate basin shape that follows the underlying structure of the Central Graben. The difference between the revised base-Quaternary and the traditional base-Quaternary reaches a maximum of over 600 ms TWT or approximately 540 m in the south-west with over 300 ms TWT or approximately 270 m at the Josephine well (56° 36.11'N, 2° 27.09'E) in the centre of the basin. Mapping this new base-Quaternary allows for the interpretation of the paleo-envionrment during the earliest Quaternary. Seismic attribute analysis indicates a deep water basin with sediment deposition from multiple deltas and redistribution by deep

  2. Quaternary geologic map of the Winnipeg 4 degrees x 6 degrees quadrangle, United States and Canada

    Science.gov (United States)

    Fullerton, D. S.; Ringrose, S.M.; Clayton, Lee; Schreiner, B.T.; Goebel, J.E.

    2000-01-01

    The Quaternary Geologic Map of the Winnipeg 4? ? 6? Quadrangle, United States and Canada, is a component of the U.S. Geological Survey Quaternary Geologic Atlas of the United States map series (Miscellaneous Investigations Series I-1420), an effort to produce 4? ? 6? Quaternary geologic maps, at 1:1 million scale, of the entire conterminous United States and adjacent Canada. The map and the accompanying text and supplemental illustrations provide a regional overview of the areal distributions and characteristics of surficial deposits and materials of Quaternary age (~1.8 Ma to present) in parts of North Dakota, Minnesota, Manitoba, and Saskatchewan. The map is not a map of soils as soils are recognized in agriculture. Rather, it is a map of soils as recognized in engineering geology, or of substrata or parent materials in which agricultural soils are formed. The map units are distinguished chiefly on the basis of (1)genesis (processes of origin) or environments of deposition: for example, sediments deposited primarily by glacial ice (glacial deposits or till), sediments deposited in lakes (lacustrine deposits), or sediments deposited by wind (eolian deposits); (2) age: for example, how long ago the deposits accumulated; (3) texture (grain size)of the deposits or materials; (4) composition (particle lithology) of the deposits or materials; (5) thickness; and (6) other physical, chemical, and engineering properties. Supplemental illustrations show (1) temporal correlation of the map units, (2) the areal relationships of late Wisconsin glacial ice lobes and sublobes, (3) temporal and spatial correlation of late Wisconsin glacial phases, readvance limits, and ice margin stillstands, (4) temporal and stratigraphic correlation of surface and subsurface glacial deposits in the Winnipeg quadrangle and in adjacent 4? ? 6? quadrangles, and (5) responsibility for state and province compilations. The database provides information related to geologic hazards (for example

  3. Extensive Quaternary glaciations in eastern Turkey

    Science.gov (United States)

    Yeşilyurt, Serdar; Akçar, Naki; Doǧan, Uǧur; Yavuz, Vural; Ivy-Ochs, Susan; Vockenhuber, Christof; Schlunegger, Fritz; Schlüchter, Christian

    2016-04-01

    During cold periods in the Quaternary, global ice volume increased and as a result valley glaciers advanced and the vice versa occurred during the warm periods. Quaternary glacier fluctuations had been also recorded in the Turkish mountains. Recently, the chronology of Late Quaternary advances in the northern and western Turkish mountains was reconstructed by surface exposure dating. However, these advances in the eastern Turkey are not dated yet. In this study, we investigated paleoglaciations in Kavuşşahap Mountains, which is located to the south of Lake Van in eastern Turkey. These mountains are one of the extensively glaciated areas in Turkey. Glacial activity is evidenced by more than 20 U-shaped valleys. For instance, one of the prominent and well-preserved glacial landscapes of Turkey is situated in the Narlıca valley system. Lateral and terminal moraines in the valley system indicate more than 10 glacial advances. To build their chronology, 39 erratic carbonaceous boulders were sampled for surface exposure dating with cosmogenic 36Cl. We also reconstructed the ice margin reconstruction of the Narlıca paleoglacier using the accumulation area ratio and area-altitude balance ratio approaches. We estimated an equilibrium line altitude (ELA) of ca. 2900 m above sea level based on the maximum ice extend, which implied ca. 800 m decrease in the ELA during the Late Quaternary in comparison to the lower bound of the modern ELA estimate. The first results of the surface exposure dating will be presented.

  4. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and pr

  5. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  6. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.|info:eu-repo/dai/nl/304828971; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  7. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and pr

  8. Hydrothermal alteration of sediments associated with surface emissions from the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N.; Esquer P., I.; Elders, W.A.; Collier, P.C.; Hoagland, J.R.

    1981-01-01

    A study of the mineralogical changes associated with these hydrothermal vents was initiated with the aim of developing possible exploration tools for geothermal resources. The Cerro Prieto reservoir has already been explored by extensive deep drilling so that relationships between surface manifestations and deeper hydrothermal processes could be established directly. Approximately 120 samples of surface sediments were collected both inside and outside of the vents. The mineralogy of the altered sediments studied appears to be controlled by the type of emission. A comparison between the changes in mineralogy due to low temperature hydrothermal activity in the reservoir, seen in samples from boreholes, and mineralogical changes in the surface emission samples shows similar general trends below 180 C: increase of quartz, feldspar and illite, with subsequent disappearance of kaolinite, montmorillonite, calcite and dolomite. These mineral assemblages seem to be characteristic products of the discharge from high intensity geothermal fields.

  9. Composition and provenance of Late Pleistocene-Holocene alluvial sediments of the eastern Andean piedmont between 33 and 34° S (Mendoza Province, Argentina)

    Science.gov (United States)

    Mehl, A.; Blasi, A.; Zárate, M.

    2012-12-01

    The Andean cordillera, and its piedmont in the central western Argentina, has been long considered as one of the main source areas of detritus for the Chaco-Pampean plain sand dune fields and loess/loess-like deposits of central Argentina. The main goal of this study is to evaluate the composition of the late Pleistocene-Holocene alluvial deposits of the Andes cordillera piedmont, from 33° to 34° S. The results are interpreted in the context of the regional geology, tectonic setting of the study area and its implications in the continent-wide perspective of modern alluvial sands proposed by Potter (1994). Sampling was conducted at the alluvial stratigraphic sequences of four study sites along three Andean piedmont arroyos; modal mineralogy in the very fine sand fraction (3 phi to 4 phi) was determined using standard petrographic microscope methods. Q:F:LF average compositions indicate that the Late Pleistocene-Holocene very fine-grained alluvial sands of the Cordillera Frontal piedmont reflects the modern lithic arenites of the Argentine Association reported by Potter (1994). The results show two geologically distinct sources in the catchment areas, volcaniclastic and metamorphic rocks. High concentrations of mica and volcanic glass are likely related to particle morphologies and to the deposition sedimentary environment recorded in the alluvial sequences—floodplains. The overabundance of micas over the volcanic glass in the mid-late Holocene alluvial sequence indicates the drainage of a metamorphic area at the expense of other lithological sources. Source areas are located mainly in the Frontal cordillera, and to a lesser extent, in the piedmont Tertiary deposits, another likely source for the analyzed Quaternary alluvial sediments. The mineralogical signature of the late Pleistocene and Holocene alluvial sequences is in agreement with the composition of the southern Pampean sand mantles, loess and loess-like deposits mainly formed by a volcanic mineral

  10. Mineralogy and composition of the oceanic mantle

    Science.gov (United States)

    Putirka, Keith; Ryerson, F.J.; Perfit, Michael; Ridley, W. Ian

    2011-01-01

    The mineralogy of the oceanic basalt source region is examined by testing whether a peridotite mineralogy can yield observed whole-rock and olivine compositions from (1) the Hawaiian Islands, our type example of a mantle plume, and (2) the Siqueiros Transform, which provides primitive samples of normal mid-ocean ridge basalt. New olivine compositional data from phase 2 of the Hawaii Scientific Drilling Project (HSDP2) show that higher Ni-in-olivine at the Hawaiian Islands is due to higher temperatures (T) of melt generation and processing (by c. 300°C) related to the Hawaiian mantle plume. DNi is low at high T, so parental Hawaiian basalts are enriched in NiO. When Hawaiian (picritic) parental magmas are transported to shallow depths, olivine precipitation occurs at lower temperatures, where DNi is high, leading to high Ni-in-olivine. Similarly, variations in Mn and Fe/Mn ratios in olivines are explained by contrasts in the temperatures of magma processing. Using the most mafic rocks to delimit Siqueiros and Hawaiian Co and Ni contents in parental magmas and mantle source compositions also shows that both suites can be derived from natural peridotites, but are inconsistent with partial melting of natural pyroxenites. Whole-rock compositions at Hawaii and Siqueiros are also matched by partial melting experiments conducted on peridotite bulk compositions. Hawaiian whole-rocks have elevated FeO contents compared with Siqueiros, which can be explained if Hawaiian parental magmas are generated from peridotite at 4-5 GPa, in contrast to pressures of slightly greater than 1 GPa for melt generation at Siqueiros; these pressures are consistent with olivine thermometry, as described in an earlier paper. SiO2-enriched Koolau compositions are reproduced if high-Fe Hawaiian parental magmas re-equilibrate at 1-1·5 GPa. Peridotite partial melts from experimental studies also reproduce the CaO and Al2O3 contents of Hawaiian (and Siqueiros) whole-rocks. Hawaiian magmas have TiO2

  11. Evidence of Himalayan erosional event at approx. 0.5 Ma from a sediment core from the equatorial Indian Ocean in the vicinityof ODP Leg 116 sites

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Gupta, S.M.; Mislankar, P.G.; Rao, B.R.; Parthiban, G.; Roelandts, I.; Patil, S.K.

    A sediment core collected from an area _100 miles south of the ODP Leg 116 (distal Bengal Fan) in the equatorial Indian Ocean was investigated for microfossils, mineralogy, mineral chemistry, magnetic susceptibility, grain size, major, minor...

  12. Surface chemistry and mineralogy. [of planet Mars

    Science.gov (United States)

    Banin, A.; Clark, B. C.; Waenke, H.

    1992-01-01

    The accumulated knowledge on the chemistry and mineralogy of Martian surface materials is reviewed. Pertinent information obtained by direct analyses of the soil on Mars by the Viking Landers, by remote sensing of Mars from flyby and orbiting spacecraft, by telescopic observations from earth, and through detailed analyses of the SNC meteorites presumed to be Martian rocks are summarized and analyzed. A compositional model for Mars soil, giving selected average elemental concentrations of major and trace elements, is suggested. It is proposed that the fine surface materials on Mars are a multicomponent mixture of weathered and nonweathered minerals. Smectite clays, silicate mineraloids similar to palagonite, and scapolite are suggested as possible major candidate components among the weathered minerals.

  13. Stable NRM and mineralogy in Allende - Chondrules

    Science.gov (United States)

    Wasilewski, P. J.; Saralker, C.

    The main objective of the present investigation is related to a description of the magnetic and mineralogic contrasts between chondrules which have a natural remanent magnetization (NRM) vector that is ultrastable during alternating field (AF) demagnetization, and those which have unstable NRM vectors when subjected to the same treatment. The results presented in the present investigation together with new magnetic results from Allende listed in a summary provided by Wasilewski (1981) are used as a basis to argue that the stable NRM in Allende was acquired during a sulfidation event. Attention is given to magnetic phases in Allende, experimental results obtained in magnetic studies conducted with 20 chondrules, and a magnetization model for Allende.

  14. Clay mineralogy in agrochernozems of western Ukraine

    Science.gov (United States)

    Papish, I. Ya.; Chizhikova, N. P.; Poznyak, S. P.; Varlamov, E. B.

    2016-10-01

    The mineralogy of clay fractions separated from deep low-humus deep-gleyic loamy typical agrochernozems on loess-like loams of the Upper Bug and Dniester uplands in the Central Russian loess province of Ukraine consists of complex disordered interstratifications with the segregation of mica- and smectite-type layers (hereafter, smectite phase), tri- and dioctahedral hydromicas, kaolinite, and chlorite. The distribution of the clay fraction is uniform. The proportions of the layered silicates vary significantly within the profile: a decrease in the content of the smectite phase and a relative increase in the content of hydromicas up the soil profile are recorded. In the upper horizons, the contents of kaolinite and chlorite increase, and some amounts of fine quartz, potassium feldspars, and plagioclases are observed. This tendency is observed in agrochernozems developed on the both Upper Bug and Dniester uplands. The differences include the larger amounts of quartz, potassium feldspars, and plagioclases in the clay material of the Upper Bug Upland, while the contents of the smectite phase in the soil profiles of the areas considered are similar. An analogous mineral association is noted in podzolized agrochernozems on loess-like deposits in the Cis-Carpathian region of the Southern Russian loess province developed on the Prut-Dniester and Syan-Dniester uplands. The distribution of particle-size fractions and the mineralogy of the clay fraction indicate the lithogenic heterogeneity of the soil-forming substrate. When the drifts change, the mineral association of the soils developed within the loess-like deposits gives place to minerals dominated by individual smectite with some mica-smectite inter stratifications, hydromicas, and chlorite.

  15. Date noi privind compozitia mineralogica a siltului lutitic de la Dumbrava, judetul Cluj (New Mineralogical Data on the Clayey Silt from Dumbrava (Cluj County

    Directory of Open Access Journals (Sweden)

    Lucret̡ia Ghergari

    2000-04-01

    Full Text Available New Mineralogical Data on the Clayey Silt from Dumbrava (Cluj County. New mineralogical data on the lutitic silt occurrence from the Dumbrava (Cluj County, Romania, based on TEM and X-ray diffraction studies, are presented in the paper. Mainly kaolinite, and subordinately illite and illite/montmorillonite represent the mineralogical compounds of the clayey fraction of the rock. The lutitic silt represents a local facies, sedimented in subaquatic environments (a small lake or pool after a short-distance transport from the sources. The source for the brown clays was probably a paleosoil formed nearby magmatic rocks. The source for the light coloured clays (creamy gray was the alterated zone of metamorphic rocks.

  16. Sand sources and transport pathways for the San Francisco Bay coastal system, based on X-ray diffraction mineralogy

    Science.gov (United States)

    Hein, James R.; Mizell, Kira; Barnard, Patrick L.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The mineralogical compositions of 119 samples collected from throughout the San Francisco Bay coastal system, including bayfloor and seafloor, area beaches, cliff outcrops, and major drainages, were determined using X-ray diffraction (XRD). Comparison of the mineral concentrations and application of statistical cluster analysis of XRD spectra allowed for the determination of provenances and transport pathways. The use of XRD mineral identifications provides semi-quantitative compositions needed for comparisons of beach and offshore sands with potential cliff and river sources, but the innovative cluster analysis of XRD diffraction spectra provides a unique visualization of how groups of samples within the San Francisco Bay coastal system are related so that sand-sized sediment transport pathways can be inferred. The main vector for sediment transport as defined by the XRD analysis is from San Francisco Bay to the outer coast, where the sand then accumulates on the ebb tidal delta and also moves alongshore. This mineralogical link defines a critical pathway because large volumes of sediment have been removed from the Bay over the last century via channel dredging, aggregate mining, and borrow pit mining, with comparable volumes of erosion from the ebb tidal delta over the same period, in addition to high rates of shoreline retreat along the adjacent, open-coast beaches. Therefore, while previously only a temporal relationship was established, the transport pathway defined by mineralogical and geochemical tracers support the link between anthropogenic activities in the Bay and widespread erosion outside the Bay. The XRD results also establish the regional and local importance of sediment derived from cliff erosion, as well as both proximal and distal fluvial sources. This research is an important contribution to a broader provenance study aimed at identifying the driving forces for widespread geomorphic change in a heavily urbanized coastal-estuarine system.

  17. Mineralogy and geochemistry of Bobov Dol coals, Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Vassilev, S.V.; Yossifova, M.G.; Vassileva, C.G. (Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Applied Mineralogy)

    1994-10-01

    The mineralogy, elemental composition and modes of occurrence of 49 elements in nine composite samples of Bobov Dol high-ash coals were studied by optical microscopy, scanning and transmission electron microscopy, X-ray diffractometry and chemical analysis. The major minerals were quartz, kaolinite, illite, plagioclase and K-feldspar and the minor minerals and phases were pyrite, marcasite, siderite, calcite, dolomite, gypsum, muscovite, montmorillonite and volcanic glass. The accessory minerals include a wide variety of minerals, such as galena, pyrrhotite, magnetite, hematite, goethite, chromite, rutile, anatase, corundum, gibbsite, biotite, chlorite, zircon, enstatite, garnet, jarosite, alunite, barite, polyhalite, aragonite, ankerite, witherite, apatite, halite and sylvite. The modes of occurrence and some genetic peculiarities of the above-mentioned minerals are described. Thirty-three elements occurred in concentrations higher than the respective Clarke values; especially S, Rb, Nb, Hf, Zn, Cu, Pb, Mn, Ti and U. The concentration trends and modes of occurrence of the trace elements are also discussed. In decreasing order of significance, the trace elements probably occur as element-organic compounds, as impurities in the mineral constituents, as major components in the minerals, as major and impurity components in the inorganic amorphous constituents, and in the fluid constituents. The Bobov Dol coals have undergone complex syngetenic, diagenetic and epigenetic mineralization processes associated with hydrothermal and volcanic activities. These processes were also accompanied by intensive tectonic movements, and possibly, by a later change from continental to marine sedimentation in the area after burial of the coal. 38 refs., 1 fig., 6 tabs., 5 plates.

  18. Gela submarine slide: gigantic basin-wide event in the Plio-Quaternary foredeep of Sicily

    Energy Technology Data Exchange (ETDEWEB)

    Argnani, A.; Trincardi, F.

    1988-08-01

    The Gela basin is a Pliocene-Quaternary foredeep basin located at the front of the Maghrebian fold-thrust belt of Sicily, filled with 2,500 m-thick shallowing-upward marine sediments. An important contribution to the basin fill comes from a huge, basin-wide submarine slide which extends for 3,500 km/sup 2/ and thickens as much as 450 m; the estimated sediment volume involved in the slide is close to 1,000 km/sup 3/. The authors investigation used more than 3,000 km of multichannel and single-channel seismic reflection profiles. The slide depositional geometries and facies relationships have been reconstructed from seismic interpretation to provide insight into transport and emplacement mechanisms. Apparently, the slide was not simply deposited via mass transfer from the slope into the basin. Indeed, the bulk of the slide is composed of basin sediments plastically deformed under the gravitational force driven by the correspondent slope sediments. Such a deformation occurred above an extremely effective decollement surface which controlled the slide distribution throughout the basin. More localized decollement planes are, however, present within the slide body and contributed to its complex deformation. The slide can thus be considered the result of a generalized gravitational collapse which affected the sediments lying above a peculiar decollement horizon. A general uplift characterized the late Quaternary evolution of the area, and volcanic activity was quite widespread and documented in the historical record. A punctuated episode of energy release (volcanic related ), superimposed to the uplift trend, may have triggered the slide in conjunction with potentially easy detachment of a decollement.

  19. Environmental Magnetic Signature Of Late Quaternary Climate and Paleoceanography in the Bering Sea

    Science.gov (United States)

    Platzman, E. S.; Lund, S.; Kirby, M. E.

    2014-12-01

    High latitude drilling during IODP expedition 323 in the Bering Sea provides a unique opportunity to study in detail the evolution of Quaternary paleoceanography, climate and glacial history of the Bering Sea gateway to the Arctic Ocean. Our study focuses on a 400 ky interval of Quaternary marine sediments cored along the Bering Slope. Samples for magnetic analysis were obtained from sites U1339, U1343, U1344, U1345, at depths of 1008-3484 m. Sediments in these cores are a mixture of siliclastic material, derived primarily from terrigeneous sources, and biogenic material. Detailed measurements of the variation in bulk magnetic properties including natural remanent magnetization (NRM), susceptibility, ARM, and IRM, have been used to monitor changes in concentration, composition and grainsize of the magnetic components. In addition, sediment grain size analysis was preformed on biogenic free aliquots at selected intervals. Our results indicate that the dramatic bimodal magnetic intensity signal that alternates between a strong and weak NRM and magnetic susceptibility is associated with relatively course and fine grain sizes repectively. This is the opposite to the pattern estimated by our initial IODP Ex. 323 reports. Current models propose that, as has been observed in the North Atlantic, high intensities are likely to be related to high contributions of terrigenous and glaciomarine sediments deposited during glacial periods and low intensities are likely to occur during interglacials when continental sediments become trapped on the on the shelf. Contrary to this hypothesis, however, we find compelling evidence for a substantial increase in terrigenous input during the interglacial periods and what appears to be a predominantly pelagic signal during the glacial periods. Comparison of our data with other proxy data including oxygen isotopes, NGR, GRA allows us to investigate the possible causal links between these changes and the environmental history of the North

  20. Reviving legacy clay mineralogy data and metadata through the IEDA-CCNY Data Internship Program

    Science.gov (United States)

    Palumbo, R. V.; Randel, C.; Ismail, A.; Block, K. A.; Cai, Y.; Carter, M.; Hemming, S. R.; Lehnert, K.

    2016-12-01

    Reconstruction of past climate and ocean circulation using ocean sediment cores relies on the use of multiple climate proxies measured on well-studied cores. Preserving all the information collected on a sediment core is crucial for the success of future studies using these unique and important samples. Clay mineralogy is a powerful tool to study weathering processes and sedimentary provenance. In his pioneering dissertation, Pierre Biscaye (1964, Yale University) established the X-Ray Diffraction (XRD) method for quantitative clay mineralogy analyses in ocean sediments and presented data for 500 core-top samples throughout the Atlantic Ocean and its neighboring seas. Unfortunately, the data only exists in analog format, which has discouraged scientists from reusing the data, apart from replication of the published maps. Archiving and preserving this dataset and making it publicly available in a digital format, linked with the metadata from the core repository will allow the scientific community to use these data to generate new findings. Under the supervision of Sidney Hemming and members of the Interdisciplinary Earth Data Alliance (IEDA) team, IEDA-CCNY interns digitized the data and metadata from Biscaye's dissertation and linked them with additional sample metadata using IGSN (International Geo-Sample Number). After compilation and proper documentation of the dataset, it was published in the EarthChem Library where the dataset will be openly accessible, and citable with a persistent DOI (Digital Object Identifier). During this internship, the students read peer-reviewed articles, interacted with active scientists in the field and acquired knowledge about XRD methods and the data generated, as well as its applications. They also learned about existing and emerging best practices in data publication and preservation. Data rescue projects are a fun and interactive way for students to become engaged in the field.

  1. Stratigraphy, mineralogy, and origin of layered deposits inside Terby crater, Mars

    Science.gov (United States)

    Ansan, V.; Loizeau, D.; Mangold, N.; Le Mouélic, S.; Carter, J.; Poulet, F.; Dromart, G.; Lucas, A.; Bibring, J.-P.; Gendrin, A.; Gondet, B.; Langevin, Y.; Masson, Ph.; Murchie, S.; Mustard, J. F.; Neukum, G.

    2011-01-01

    The 174 km diameter Terby impact crater (28.0°S-74.1°E) located on the northern rim of the Hellas basin displays anomalous inner morphology, including a flat floor and light-toned layered deposits. An analysis of these deposits was performed using multiple datasets from Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter missions, with visible images for interpretation, near-infrared data for mineralogical mapping, and topography for geometry. The geometry of layered deposits was consistent with that of sediments that settled mainly in a sub-aqueous environment, during the Noachian period as determined by crater counts. To the north, the thickest sediments displayed sequences for fan deltas, as identified by 100 m to 1 km long clinoforms, as defined by horizontal beds passing to foreset beds dipping by 6-10° toward the center of the Terby crater. The identification of distinct sub-aqueous fan sequences, separated by unconformities and local wedges, showed the accumulation of sediments from prograding/onlapping depositional sequences, due to lake level and sediment supply variations. The mineralogy of several layers with hydrated minerals, including Fe/Mg phyllosilicates, supports this type of sedimentary environment. The volume of fan sediments was estimated as >5000 km 3 (a large amount considering classical martian fan deltas such as Eberswalde (6 km 3)) and requires sustained liquid water activity. Such a large sedimentary deposition in Terby crater is characteristic of the Noachian/Phyllosian period during which the environment favored the formation of phyllosilicates. The latter were detected by spectral data in the layered deposits of Terby crater in three distinct layer sequences. During the Hesperian period, the sediments experienced strong erosion, possibly enhanced by more acidic conditions, forming the current morphology with three mesas and closed depressions. Small fluvial valleys and alluvial fans formed subsequently

  2. Automated Quantitative Rare Earth Elements Mineralogy by Scanning Electron Microscopy

    Science.gov (United States)

    Sindern, Sven; Meyer, F. Michael

    2016-09-01

    Increasing industrial demand of rare earth elements (REEs) stems from the central role they play for advanced technologies and the accelerating move away from carbon-based fuels. However, REE production is often hampered by the chemical, mineralogical as well as textural complexity of the ores with a need for better understanding of their salient properties. This is not only essential for in-depth genetic interpretations but also for a robust assessment of ore quality and economic viability. The design of energy and cost-efficient processing of REE ores depends heavily on information about REE element deportment that can be made available employing automated quantitative process mineralogy. Quantitative mineralogy assigns numeric values to compositional and textural properties of mineral matter. Scanning electron microscopy (SEM) combined with a suitable software package for acquisition of backscatter electron and X-ray signals, phase assignment and image analysis is one of the most efficient tools for quantitative mineralogy. The four different SEM-based automated quantitative mineralogy systems, i.e. FEI QEMSCAN and MLA, Tescan TIMA and Zeiss Mineralogic Mining, which are commercially available, are briefly characterized. Using examples of quantitative REE mineralogy, this chapter illustrates capabilities and limitations of automated SEM-based systems. Chemical variability of REE minerals and analytical uncertainty can reduce performance of phase assignment. This is shown for the REE phases parisite and synchysite. In another example from a monazite REE deposit, the quantitative mineralogical parameters surface roughness and mineral association derived from image analysis are applied for automated discrimination of apatite formed in a breakdown reaction of monazite and apatite formed by metamorphism prior to monazite breakdown. SEM-based automated mineralogy fulfils all requirements for characterization of complex unconventional REE ores that will become

  3. Distribution of surficial sediments in the Southern Evoikos and Petalioi Gulfs, Greece

    Directory of Open Access Journals (Sweden)

    A.P. KARAGEORGIS

    2012-12-01

    Full Text Available A series of 123 surficial sediment samples from the Southern Evoikos and Petalioi Gulfs was studied for grain-size properties, carbonate content and mineralogical composition. Distribution of the sediments revealed two sedimentary provinces. The first concerns the Southern Evoikos Gulf, characterised by silty sediments with relatively low carbonate content. Quartz, feldspars, micas, clay and carbonate minerals are the major mineralogical components of the sediments. These sediments are the result of the Asopos River supply during Holocene and they contribute to the formation of smooth bottom morphology. The second province concerns the Petalioi Gulf (Northern and Southern, where the surficial sediments are mainly sandy and characterised by very high carbonate content. Their mineralogical composition reflects the lithology of the drainage basin. Since the modern terrigenous solid supply is limited, these sediments are not considered as products of recent sedimentation, but older deposits (relict sands. Their presence at such depths is justified by sea-level fluctuations and their preservation is due to the low sedimentation rate in the Petalioi Gulf, in combination with the strong hydrodynamic status of the area.

  4. Meteorite falls in Bulgaria: Reappraisal of mineralogy, chemistry, and classification

    Science.gov (United States)

    Dekov, Vesselin; Rochette, Pierre; Gattacceca, JéRôMe

    2017-08-01

    We present a summary of the mineralogy, mineral chemistry, and magnetic characteristics of all the five Bulgarian meteorite falls. We report the first mineralogical descriptions, chemical analyses, and magnetic measurements of the Konevo (1931) and Silistra (1917) meteorites. We classify Konevo as LL5, and Silistra as an ungrouped achondrite with HED affinities. Pavel (1966; previously classified as an H5) is reclassified as H3-anomalous. We also provide precise mineralogy and mineral chemistry of the Virba meteorite (1873, L6), and more details on the mineral chemistry of Gumoschnik (1904, H5).

  5. Quaternary transgressive and regressive depositional sequences in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the interpretation more than 4000 km sparker single channel seismic profiles and the comparison with Borehole DZQ4 on the outer shelf of the East China Sea (ECS), the seismic sequences, sedimentary facies and paleo-sedimentary environment are studied to establish the chronology framework and discuss the Quaternary transgressive and regressive sequences of the ECS shelf as well as their response to glacio-eustatic sea-level changes. The sea level of the ECS fluctuated with global climate changes in the Quaternary. During the sea level rise, the Pacific tidal wave impacted actively on the ECS continental shelf and the reciprocating tidal currents in NW-SE direction formed tidal sand ridges, which represent large transgressive deposits visible on the seismic profiles. In response to sea level fall, the Yangtze River deltas prograded seaward and built massive subaqueous deltas to form regressive sequences on the seismic profiles. Alternative transgression and regression sequences were vertically distributed on the ECS shelf with the frequent eustacy in the Quaternary. The gentle slope of the ECS shelf makes it possible for the coastline to migrate hundreds of kilometers forth and back on the shelf because of tens of meters sea level changes, in the meanwhile, the Yangtze River discharged large amounts of sediments into the ECS resulting in large-scale subaqueous deltas and tidal sand ridges. There have developed 3 stages of tidal sand ridges and 4 stages of deltas on the ECS shelf since oxygen isotope stage 8.

  6. [Quaternary prevention: containment as an ethical necessity].

    Science.gov (United States)

    Martínez González, C; Riaño Galán, I; Sánchez Jacob, M; González de Dios, J

    2014-12-01

    The growing capacity of medicine to generate more iatrogenic events than ever, and the risk of unsustainability of health systems have led to new prevention concept: quaternary prevention aimed at restraining medicalization. Quaternary prevention is essential in the phenomenon called disease mongering, which could be translated as commercialization of disease. Encouraging this sort of prevention and halting the consequences of disease mongering requires the development of all the institutional potential for prevention, as well as all the personal willingness for restraint; it involves separating us from the unnecessary auspices of industry, being critical of our work, not being maleficent, respecting the principle of justice as managers of the limited public resources and making ourselves feel responsible for the social cost resulting from medical decisions. From this point of view, this work analyses neonatal screening, developments in the area of neonatology and primary health care.

  7. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  8. Geochemistry and mineralogy of mafic Icelandic hyaloclastites

    Science.gov (United States)

    Hudak, M. R.; Feineman, M. D.; Eyer, C.; Bindeman, I. N.; Sigmarsson, O.

    2016-12-01

    Hyaloclastite in the crust may be a cryptic contaminant contributing to some volatile-rich Icelandic basalts and in some places reach 2.5 km1. Hyaloclastites are highly fragmented composites of lithics, glass, and crystals in a palagonite matrix that form as a result of magma-ice or magma-water interactions. These rocks have high water content and porosity and a high initial glass content, which makes them susceptible to rapid alteration by ambient or hydrothermal waters and potentially fast digestion by magmas. Due to low density and ductility, they have the potential to stall ascending mantle-derived magmas to form sills, and in the process may contribute exotic volatile or fluid-mobile components. We have characterized the geochemistry and mineralogy of 18 hyaloclastite samples from the Reykjanes Peninsula (RP), Vestmannajyar, and the southern coast of Iceland. Major and trace elements were obtained using ICP-AES and ICP-MS, respectively, and mineralogy was determined by XRD. Loss on ignition is highly variable (0.44 - 15.7 wt.%) and positively correlated with alkali loss reflected in the Chemical Index of Alteration [34.8 - 51.3; CIA = Al2O3/(Al2O3+CaO+Na2O+K2O)]. Primitive mantle normalized multi-element plots for RP hyaloclastites are broadly similar to those for unaltered RP Holocene basalts. Two samples have trace element profiles resembling those of picrites in the region. The samples from the south coast and Vestmannaeyjar have OIB-like enrichments similar to local Holocene basalts. Five well-sorted hyaloclastite samples have broad humps in their XRD patterns from 20-50° 2q. These samples contain only primary magmatic mineral phases (plagioclase, olivine, and pyroxene), if any, while other hyaloclastites contain both primary phases and secondary alteration phases including halite, calcite, clays, chlorite, and zeolites. Preliminary O and H isotope investigation demonstrates large ranges in both parameters. Future work will include oxygen isotope analyses

  9. PCA for predicting quaternary structure of protein

    Institute of Scientific and Technical Information of China (English)

    Tong WANG; Hongbin SHEN; Lixiu YAO; Jie YANG; Kuochen CHOU

    2008-01-01

    The number and arrangement of subunits that form a protein are referred to as quaternary structure. Knowing the quaternary structure of an uncharacterized protein provides clues to finding its biological function and interaction process with other molecules in a biological system. With the explosion of protein sequences generated in the Post-Genomic Age, it is vital to develop an automated method to deal with such a challenge. To explore this prob-lem, we adopted an approach based on the pseudo position-specific score matrix (Pse-PSSM) descriptor, proposed by Chou and Shen, representing a protein sample. The Pse-PSSM descriptor is advantageous in that it can combine the evolution information and sequence-correlated informa-tion. However, incorporating all these effects into a descriptor may cause 'high dimension disaster'. To over-come such a problem, the fusion approach was adopted by Chou and Shen. A completely different approach, linear dimensionality reduction algorithm principal component analysis (PCA) is introduced to extract key features from the high-dimensional Pse-PSSM space. The obtained dimension-reduced descriptor vector is a compact repre-sentation of the original high dimensional vector. The jack-knife test results indicate that the dimensionality reduction approach is efficient in coping with complicated problems in biological systems, such as predicting the quaternary struc-ture of proteins.

  10. An Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient

    Science.gov (United States)

    Jakobsson, M.; Dowdeswell, J. A.; Canals, M.; Todd, B. J.; Dowdeswell, E. K.; Hogan, K. A.

    2014-12-01

    In the past two decades there have been several advances that make the production of an atlas of submarine glacial landforms timely. First is the development of high-resolution imaging technologies; multi-beam echo-sounding or swath bathymetry that allows the detailed mapping of the sea floor at water depths of tens to thousands of metres across continental margins, and 3-D seismic methods that enable the visualisation of palaeo-continental shelves in Quaternary sediments and ancient palaeo-glacial rocks (e.g. Late Ordovician of Northern Africa). A second technological development is that of ice-breaking or ice-strengthened ships that can penetrate deep into the ice-infested waters of the Arctic and Antarctic, to deploy the multibeam systems. A third component is that of relevance - through both the recognition that the polar regions, and especially the Arctic, are particularly sensitive parts of the global environmental system and that these high-latitude margins (both modern and ancient) are likely to contain significant hydrocarbon resources. An enhanced understanding of the sediments and landforms of these fjord-shelf-slope systems is, therefore, of increasing importance to both academics and industry. We are editing an Atlas of Submarine Glacial Landforms that presents a series of individual contributions that describe, discuss and illustrate features on the high-latitude, glacier-influenced sea floor. Contributions are organised in two ways: first, by position on a continental margin - from fjords, through continental shelves to the continental slope and rise; secondly, by scale - as individual landforms and assemblages of landforms. A final section provides discussion of integrated fjord-shelf-slope systems. Over 100 contributions by scientists from many countries contain descriptions and interpretation of swath-bathymetric data from both Arctic and Antarctic margins and use 3D seismic data to investigate ancient glacial landforms. The Atlas will be

  11. Reply to the comment on "Geochemistry of buried river sediments from Ghaggar Plains, NW India: Multi-proxy records of variations in provenance, paleoclimate, and paleovegetation patterns in the Late Quaternary" by Singh et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 449 (2016) 85-100

    DEFF Research Database (Denmark)

    Singh, Ajit; Paul, Debajyoti; Sinha, Rajiv;

    2016-01-01

    In the comment on our paper (this issue), Clift et al. (2016) compared our recently reported radiogenic Nd-isotopic record in two drill cores (Singh et al., 2016) with those from the Hakra floodplain sediments and Indus Delta sediments. While they agree with the concept of erosion patterns...... in the western Himalayan sources being climatically modulated, they offer an alternative interpretation for our reported variability in the radiogenic Nd-isotopic values. Here, we show that the Nd-isotopic values for the Holocene succession instead can be explained by the bedrock geology of the source region...

  12. Late Quaternary environments, vegetation and agriculture in northern New Zealand

    Science.gov (United States)

    Horrocks, M.; Nichol, S. L.; Augustinus, P. C.; Barber, I. G.

    2007-03-01

    A sedimentological and plant microfossil history of the Late Quaternary is preserved in two sediment cores from early Polynesian ditch systems on southern Aupouri Peninsula. The study places human activities into a geomorphological and ecological context and allows comparison of natural and anthropogenic effects on two different geological settings: a floodplain and a relatively closed peat swamp. The data fill part of the current gap in the environmental record from northern New Zealand, namely MIS 3 (57k-26k yr BP). There is evidence for an increase in fire frequency in the region after 40k 14C yr BP, suggesting a shift to drier (and cooler) conditions. Pollen records show that conifer-hardwood forest dominated by podocarps (especially Dacrydium) prevailed prior to Polynesian arrival and deforestation within the last millennium, with Fuscopsora insignificant throughout. Both cores show sections with gaps in deposition or preservation, possible flood-stripping of peat during the pre-Holocene and mechanical disturbance by early Polynesians. The identification of prehistoric starch grains and other microremains of introduced Colocasia esculenta (taro) in both cores supports indirect evidence that the ditch systems of far northern New Zealand were used for the extensive cultivation of this crop. Copyright

  13. Sediment magnetic and paleomagnetic data from Buck Lake, Oregon

    Science.gov (United States)

    Rosenbaum, J.G.; Reynolds, R.L.; Fitzmaurice, P.L.; Drexler, J.W.; Whitney, C.G.; Adam, D.P.

    1994-01-01

    Sediment magnetic and paleomagnetic studies were conducted on a core from Buck Lake, Klamath County, Oregon, that was collected as part of an investigation into the Quaternary climate history of the western United States. This report documents the methods used to obtain paleomagnetic directions, magnetic properties, and ancillary data, and presents these data in tabular form. Adam (1993) and Adam and others (1994) describe the site, the drilling methods, and lithology of the lacustrine sediments. Rosenbaum and others (1994) present preliminary interpretations of the sediment magnetic data and show that variations in magnetic properties closely reflect changes in climate as interpreted from the pollen record.

  14. Geochemical and Mineralogical Proxies for characterizing Tsunami and Paleotsunami Deposits

    Science.gov (United States)

    Löwhagen, L.; Jankaew, K.; Kylander, M. E.; Skelton, A.; Wohlfarth, B.

    2015-12-01

    In this study we show how geochemistry and mineralogy can be used to correlate between previously dated tsunami and paleotsunami deposits in western Thailand. We do this based on cores from three parallel swales along a transect from the shoreline inland. Stratigraphy, together with geochemical and mineralogical analyses was used to correlate between tsunami and paleotsunami layers at these sites. Using element biplots (Ti-Zr, Ti-Y and Zr-Y) and mineralogical constraints, source signatures of each of the tsunami and paleotsunami layers were used to correlate between sand layers representing the 2004 tsunami and sand layers representing at least three paleotsunamis. Based on our correlations between these swales, we predict different inundation distances and directions for these paleotsunamis. Our study shows that a combination of geochemical and mineralogical analysis provides a powerful tool for correlation between tsunami and paleotsunami layers.

  15. Quaternary grabens in southernmost Illinois: Deformation near an active intraplate seismic zone

    Science.gov (United States)

    Nelson, W.J.; Denny, F.B.; Follmer, L.R.; Masters, J.M.

    1999-01-01

    Narrow grabens displace Quaternary sediments near the northern edge of the Mississippi Embayment in extreme southern Illinois, east-central United States. Grabens are part of the Fluorspar Area Fault Complex (FAFC), which has been recurrently active throughout Phanerozoic time. The FAFC strikes directly toward the New Madrid Seismic Zone (NMSZ), scene of some of the largest intra-plate earthquakes in history. The NMSZ and FAFC share origin in a failed Cambrian rift (Reelfoot Rift). Every major fault zone of the FAFC in Illinois exhibits Quaternary displacement. The structures appear to be strike-slip pull-apart grabens, but the magnitude and direction of horizontal slip and their relationship to the current stress field are unknown. Upper Tertiary strata are vertically displaced more than 100 m, Illinoian and older Pleistocene strata 10 to 30 m, and Wisconsinan deposits 1 m or less. No Holocene deformation has been observed. Average vertical slip rates are estimated at 0.01 to 0.03 mm/year, and recurrence intervals for earthquakes of magnitude 6 to 7 are on the order of 10,000s of years for any given fault. Previous authors remarked that the small amount of surface deformation in the New Madrid area implies that the NMSZ is a young feature. Our findings show that tectonic activity has shifted around throughout the Quaternary in the central Mississippi Valley. In addition to the NMSZ and southern Illinois, the Wabash Valley (Illinois-Indiana), Benton Hills (Missouri), Crowley's Ridge (Arkansas-Missouri), and possibly other sites have experienced Quaternary tectonism. The NMSZ may be only the latest manifestation of seismicity in an intensely fractured intra-plate region.

  16. The grain-size characteristics of Quaternary deposits at Xingshan near Siping in Jilin province, China

    Institute of Scientific and Technical Information of China (English)

    Maxwell A Boateng; Xikui Wang

    2006-01-01

    This research paper analyses the grain-size characteristics of the Quaternary deposits at Xingshan near Siping, Jilin province in China by employing graphic measures to study the grain size distribution and its mode of transport and deposition. The Quaternary deposits at Xingshan lie unconformable on Cretaceous rocks made of siltstone, mudstone and sandstone. The average grain size is between 8.06 to 8.55Φ (0.002 6 ~0.003 7 mm). The Quaternary deposits at Xingshan mainly compose of very fine silt to clay. The compositions of the grade are clay 63% and silt 37%. The clay size components are weathered debris transported and deposited by flowing water from the SE highlands or hills to the low lying NW Xingshan plains whereas the silty components accumulated by aoelian process. The Quaternary deposits at Xingshan accumulated in the middle and late Pleistocene interglacial periods from (459.12~39.03) ka to (88.92~7.56) ka. The standard deviation ranged from 0.96 to 1.36Φ, indicating that the sediments are moderately to poorly sorted, Coefficient of skewness ranged from 0.16~0.31 with an average skewness of 0.218, (Positively skewed towards fine). Kurtosis values (0.84~1.05) from the grain size distribution and visual inspection of the frequency curves indicate platykurtic to mesokurtic curves and unimodal to bimodal grain-size distribution. The type of deposit formation is sand dune and the source is at a distal from its provenance.

  17. Late Quaternary sedimentary features of Bear Lake, Utah and Idaho

    Science.gov (United States)

    Smoot, J.P.

    2009-01-01

    Bear Lake sediments were predominantly aragonite for most of the Holocene, reflecting a hydrologically closed lake fed by groundwater and small streams. During the late Pleistocene, the Bear River flowed into Bear Lake and the lake waters spilled back into the Bear River drainage. At that time, sediment deposition was dominated by siliciclastic sediment and calcite. Lake-level fluctuation during the Holocene and late Pleistocene produced three types of aragonite deposits in the central lake area that are differentiated primarily by grain size, sorting, and diatom assemblage. Lake-margin deposits during this period consisted of sandy deposits including well-developed shoreface deposits on margins adjacent to relatively steep gradient lake floors and thin, graded shell gravel on margins adjacent to very low gradient lake-floor areas. Throughout the period of aragonite deposition, episodic drops in lake level resulted in erosion of shallow-water deposits, which were redeposited into the deeper lake. These sediment-focusing episodes are recognized by mixing of different mineralogies and crystal habits and mixing of a range of diatom fauna into poorly sorted mud layers. Lake-level drops are also indicated by erosional gaps in the shallow-water records and the occurrence of shoreline deposits in areas now covered by as much as 30 m of water. Calcite precipitation occurred for a short interval of time during the Holocene in response to an influx of Bear River water ca. 8 ka. The Pleistocene sedimentary record of Bear Lake until ca. 18 ka is dominated by siliciclastic glacial fl our derived from glaciers in the Uinta Mountains. The Bear Lake deep-water siliciclastic deposits are thoroughly bioturbated, whereas shallow-water deposits transitional to deltas in the northern part of the basin are upward-coarsening sequences of laminated mud, silt, and sand. A major drop in lake level occurred ca. 18 ka, resulting in subaerial exposure of the lake floor in areas now covered by

  18. Late Quaternary climate variability in the Sahel: inferences from marine dust records offshore Senegal

    Science.gov (United States)

    Stuut, J. W.; Meyer, I.; Fischer, H.; Mollenhauer, G.; Mulitza, S.; Pittauerova, D.; Zabel, M.; Schulz, M.

    2008-12-01

    Societies and ecosystems in northern Africa are strongly affected by the availability of water. As a consequence, long-term absence of rainfall has very dear effects on the ecosystems, as was dramatically shown in the 70'ies and 80'ies of the 20th century. Recent high-resolution reconstructions of Sahel palaeoclimate allow for new insights into these drastic climate variations and to disentangle the effects of the different components of the climate system on African climate change. In this study we extend the instrumental record of climate variability using marine sediment cores that were retrieved off the coast of Senegal, northwest Africa. The sediment records contain continuous high-resolution records of dust sedimentation ranging from about 4,000 to about 57,000 years. A 210Pb age model for the youngest sediments allows for a matching of the proxy rainfall record with instrumental precipitation data. Specifically, variations in the grain-size distributions of the terrigenous sediment fraction, deconvolved with an end-member modelling algorithm (Weltje, 1997) are used to reconstruct rainfall variability on land throughout the late Quaternary.

  19. Magnetic mineralogy of the Mercurian lithosphere

    Science.gov (United States)

    Strauss, B. E.; Feinberg, J. M.; Johnson, C. L.

    2016-11-01

    Mercury and Earth are the only inner solar system planets with active, internally generated dynamo magnetic fields. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission recently detected magnetic fields on Mercury that are consistent with lithospheric magnetization. We investigate the physical and chemical environment of Mercury's lithosphere, past and present, to establish the conditions under which magnetization may have been acquired and modified. Three factors are particularly crucial to the determination of crustal composition and iron mineralogy: redox conditions in the planet's crust and mantle, the iron content of the lithosphere, and, for any remanent magnetization, the temperature profile of the lithosphere and its evolution over time. We explore potential mechanisms for remanence acquisition and alteration on Mercury, whose surface environment is both hot and highly reducing. The long-term thermal history of Mercury's crust plays an important role in the longevity of any remanent crustal magnetization, which may be subject to remagnetization through thermal, viscous, and shock mechanisms. This thermal and compositional framework is used both to constrain plausible candidate minerals that could carry magnetic remanence on Mercury and to evaluate their capacity to acquire and retain sufficient magnetization to be detectable from satellite orbit. We propose that iron metal and its alloys are likely to be the dominant contributors to induced and remanent magnetization in Mercury's lithosphere, with additional contributions from iron silicides, sulfides, and carbides.

  20. Olivine-dominated Asteroids: Mineralogy and Origin

    CERN Document Server

    Sanchez, Juan A; Kelley, Michael S; Cloutis, Edward A; Bottke, William F; Nesvorný, David; Lucas, Michael P; Hardersen, Paul S; Gaffey, Michael J; Abell, Paul A; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. Within our sample we distinguish two classes, one that we call pure-olivine asteroids and another referred to as olivine-rich asteroids. For the pure-olivine asteroids the olivine chemistry was found to range from ~ Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined thei...

  1. The mineralogy of ordinary chondrites and implications for asteroid spectrophotometry

    Science.gov (United States)

    Mcsween, Harry Y., Jr.; Bennett, Marvin E., III; Jarosewich, Eugene

    1991-01-01

    Published data from bulk chemical analyses of 94 ordinary chondrites are compiled in a table of normative mineralogy and discussed in detail. Significant variations in olivine, pyroxene, and metal abundance ratios are found within each chondrite class and attributed to redox processes superimposed on initial differences in metal/silicate ratios. The use of the diagrams constructed here to predict the mineralogic characteristics of asteroids on the basis of spectrophotometric observations is suggested.

  2. Synthesis of novel quaternary ammonium surfactants containing adamantane

    Institute of Scientific and Technical Information of China (English)

    Jian Wei Guo; Xing Zhong; Hua Zhu; Li Juan Feng; Ying De Cui

    2012-01-01

    A series of novel quaternary ammonium surfactants containing adamantane were designed and synthesized from 1-adamantanecarboxylic acid.The structures of target surfactants were confirmed by 1H NMR,elements analysis and FTIR.Surface properties of these surfactants were investigated.Due to the lipophilicity of adamantane,the critical micelle concentration (CMC) and C20 values of the synthesized quaternary ammonium surfactants are lower than that of conventional quaternary ammonium surfactants.

  3. River terraces and alluvial fans: The case for an integrated Quaternary fluvial archive

    Science.gov (United States)

    Mather, A. E.; Stokes, M.; Whitfield, E.

    2017-06-01

    The fluvial archive literature is dominated by research on river terraces with appropriate mention of adjacent environments such as lakes. Despite modern sedimentary basins comprising a significant (>88%) volume of distributive fluvial systems, of which alluvial fans (>1 km, archive community. Published literature is used to examine both thematic and geographical based benefits of alluvial fan research that can assist understanding of Quaternary fluvial archives. 3 regional case studies are presented that illustrate the interaction between alluvial fan and river terrace archives at Quaternary time-scales at 3 different stages of landscape evolution. These are i) continuous mountain front alluvial fans interacting with a non incising but laterally eroding axial fluvial system; ii) alluvial fans which transition into fluvial terraces as sedimentary basins shift from net aggradation to net incision and iii) tributary-junction alluvial fans that develop predominantly within incising river valley systems. A simple conceptual model is proposed to summarise the dynamic role of alluvial fans within this landscape context. The alluvial fans act as potential 'buffers' between hillslopes and river terrace records under 'top down' climate-driven high sediment supply and alluvial fan aggradation, and 'couplers' during periods of less sediment (in relation to water) discharge and alluvial fan incision. These dynamics will change with the addition of 'bottom up' controls such as main river incision, which will typically enhance the coupling effect of both systems.

  4. IODP Expeditions 303 and 306 Monitor Miocene- Quaternary Climate in the North Atlantic

    Directory of Open Access Journals (Sweden)

    Carlos Alvarez-Zarikian

    2006-03-01

    Full Text Available Introduction The IODP Expeditions 303 and 306 drilling sites were chosen for two reasons: (1 to capture Miocene-Quaternary millennial-scale climate variability in sensitive regions at the mouth of the Labrador Sea and in the North Atlantic icerafted debris (IRD belt (Ruddiman et al., 1977, and (2 to provide the sedimentary and paleomagnetic attributes, including adequate sedimentation rates, for constructinghigh-resolution isotopic and magnetic stratigraphies.High accumulation rates, reaching 20 cm ky-1, permit the study of millennial-scale variations in climate and in the Earth's magnetic fi eld over the past several million years, when the amplitude and frequency of climate variability changed substantially. Shipboard logging and scanning data (magnetic susceptibility and remanence, density, natural gamma radiation, digital images and color refl ectance and post-expedition x-ray fl uorescence (XRF scanning datahave revealed that the sediment cores recovered on Expeditions 303 and 306 contain detailed histories of millennial-scale climate and geomagnetic fi eld variability throughout the late Miocene to Quaternary epochs. The climate proxies will be integrated with paleomagnetic data to place the records of millennial-scale climate change into a high resolution stratigraphy based on oxygen isotope andrelative paleomagnetic intensity (RPI. The paleomagnetic record of polarity reversals, excursions and RPI in these cores is central to the construction of the stratigraphic template and will provide detailed documentation of geomagnetic fi eld behavior.

  5. Revised mineralogic summary of Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Bish, D.L.; Chipera, S.J.

    1989-03-01

    We have evaluated three-dimensional mineral distribution at Yucca Mountain, Nevada, using quantitative x-ray powder diffraction analysis. All data were obtained on core cuttings, or sidewall samples obtained from drill holes at and around Yucca Mountain. Previously published data are included with corrections, together with new data for several drill holes. The new data presented in this report used the internal standard method of quantitative analysis, which yields results of high precision for the phases commonly found in Yucca Mountain tuffs including opal-CT and glass. Mineralogical trends with depth previously noted are clearly shown by these new data. Glass occurrence is restricted almost without exception to above the present-day static water level (SWL), although glass has been identified below the SWL in partially zeolitized tuffs. Silica phases undergo well-defined transitions with depth, with tridymite and cristobalite occurring only above the SWL, opal-CT occurring with clinoptilolite-mordenite tuffs, and quartz most abundant below the SWL. Smectite occurs in small amounts in most samples but is enriched in two distinct zones. These zones are at the top of the vitric nonwelded base of the Tiva Canyon Member and at the top of the basal vitrophyre of the Topopah Spring Member. Our data support the presence of several zones of mordenite and clinoptilolite-heulandite as shown previously. New data on several deep clinoptililite-heulandite samples coexisting with analcime show that they are heulandite. Phillipsite has not been found in any Yucca Mountain samples, but erionite and chabazite have been found once in fractures. 21 refs., 17 figs.

  6. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2......, 4 and 5, respectively. It is not the intention of the book to give a broad review of the literature on this very wide topic. The book tries to pick up information which is of engineering importance. An obstacle to the study of sedimentation is the scale effect in model tests. Whenever small...

  7. Palaeomagnetic research on karst sediments in Slovenia

    Directory of Open Access Journals (Sweden)

    Zupan Hajna Nadja

    2010-07-01

    Full Text Available We have conducted palaeomagnetic and magnetostratigraphic research on karst sediments in Slovenia since 1997. More than 2,000samples were taken and analysed in 36 different profiles at 21 locations in caves and on the surface. Standard palaeomagnetic analyseswere used (thermal and alternating field demagnetisation, magnetic susceptibility measurements, etc.. There is no evidence of youngermarine deposition than Eocene in the SW part of Slovenia. Younger sediments occur only in caves and very rarely on the karst surface(different soils and a few remains of terrigeneous sediments. Marine and terrestrial Tertiary to Plio–Quaternary deposition occurs in theSE and E Slovenia. Chronostratigraphy of cave sediments in SW Slovenia completed by Rado Gospodarič in the 1980s was basedon Pleistocene warm/cold cycles. Later Th/U dating indicated that speleothems from different caves in Slovenia are older. New datingprincipally results from palaeomagnetism and magnetostratigraphy of cave sediments calibrated, in some sites, by Th/U, palaentologicaland geomorphological analyses. Calibrated data contributed to the reconstruction of speleogenesis, deposition in caves, and indirectly tothe evolution of karst surfaces and succession of tectonic movements. The evolution of caves in the Slovenian territory took part withinone post-Eocene karstification period. This period continues to the present, and can be subdivided into individual, but not well limited,phases related to Cenozoic palaeogeographical changes. The period contains distinct phases of massive deposition in caves with as yetstill preserved sediments dated to about 5.4–4.1 Ma (Miocene–Pliocene, 3.6–1.8 Ma (Pliocene and Quaternary, following the cessationof Miocene deposition in the Pannonian Basin in the central, E and SE Slovenia and post-Messinian evolution in the SW and W Slovenia.

  8. Proglacial hydrochemistry and sediment characteristics observed across a spectrum of glacier dynamic regimes

    Science.gov (United States)

    Crompton, J. W.; Flowers, G. E.

    2015-12-01

    The broad influence of bedrock geology on glacier dynamics has received comparatively little attention in the alpine glacier literature. Geological influences vary widely from subglacial hydrochemistry to deformable till rheology, which may be governed by the mineralogy and grain size distribution within the till. In an investigation of borehole and proglacial water at an unnamed glacier in the Donjek Range of the St. Elias Mountains, Yukon, Canada, we find that subglacial mineral precipitation exerts a significant control on the proglacial hydrochemistry and suspended sediment flux. To understand if this process is common to glaciers across the range, we collected proglacial water samples from 20 glaciers in and around the Donjek Range. From each sample, we analyzed the hydrochemistry, measured the grain size distribution (GSD) using a Mastersizer laser diffraction particle size analyzer, and analyzed the mineralogy of the suspended sediments using X-ray diffraction. We also analyzed thin sections from bedrock samples collected at the glacier margins to constrain the mineralogical input to the system. This suite of measurements permits us to investigate the discrepancies between the secondary minerals predicted by the proglacial hydrochemistry and the observed mineralogy. Given that glaciers in the sample set exhibit a range of dynamic behaviour (including surging), we investigate how the mineralogy, GSDs, and hydrochemistry vary as a function of glacier dynamics. Where we have identified correlations between surging glaciers and proglacial GSDs, we investigate the possible controls of hydrochemistry and/or mineralogy on the GSDs and thus on subglacial dynamics.

  9. Palladium-catalyzed asymmetric quaternary stereocenter formation.

    Science.gov (United States)

    Gottumukkala, Aditya L; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G; Minnaard, Adriaan J

    2012-05-29

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl(2), PhBOX, and AgSbF(6), and provides products in up to 99% enantiomeric excess, with good yields. Based on this strategy, (-)-α-cuparenone has been prepared in only two steps. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. New insights into the earliest Quaternary environments in the Central North Sea from 3D seismic

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    In the past the transition between an unconformable surface in the south to a conformable horizon towards the north has made identification and mapping the base-Quaternary in the central North Sea difficult (Sejrup et al 1991; Gatliff et al 1994). However recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) has allowed greater confidence in the correlation to the region 3D seismic datasets and thus has allowed the base-Quaternary to be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The revised base-Quaternary surface reaches a depth of 1248 ms TWT with an elongate basin shape which is significantly deeper than the traditionally mapped surface. Using RMS amplitudes and other seismic attributes the revised base-Quaternary has been investigated along the horizon and in time slice to interpret the environments of the earliest Quaternary prior to the onset of glaciation. Combined with analysis of aligned elongate furrows over 10 km long, 100 m wide and 100 m deep suggest a deep marine environment in an almost enclosed basin with persistent strong NW-SE bottom currents in the deepest parts. Pockmarks were formed by the escape of shallow gas on the sides of a small delta in the eastern part of the basin. The progradation of large deltas from both the north and south into the basin make up the majority of the deposition of sediment into the basin. Key Words: base-Quaternary; seismic interpretation; paleoenvironments References: Gatliff, R.W, Richards, P.C, Smith, K, Graham, C.C, McCormac, M, Smith, N.J.P, Long, D, Cameron, T.D.J, Evans, D, Stevenson, A.G, Bulat, J, Ritchie, J.D, (1994) 'United Kingdom offshore regional

  11. THE BINARY IMAGE OF THE DUAL OF QUATERNARY GOETHALS CODE

    Institute of Scientific and Technical Information of China (English)

    崔杰

    2002-01-01

    The 2-adic representations of codewords of the dual of quaternary Goethals code are given. By the 2-adic representations, the binary image of the dual of quaternary Goethals code under the Gray map is proved to be the nonlinear code constructed by Goethals in 1976.

  12. Investigation of hexavalent chromium sorption in serpentine sediments

    Science.gov (United States)

    Mpouras, Thanasis; Chrysochoou, Maria; Dermatas, Dimitris

    2017-02-01

    In this study the removal of hexavalent chromium (Cr6 +) by serpentine sediments was investigated in order to delineate Cr6 + sorption behavior in aquifers with ultramafic geologic background. Batch experiments were conducted in order to determine the influence of several parameters on Cr6 + removal, including the pH of the sediment solution, mineralogy, sediment's particle size and Cr6 + initial concentration. The results showed that Cr6 + removal was due to both adsorption and reduction phenomena. Reduction was attributed to the presence of a magnetic fraction in the sediment, mostly related to magnetite, which contributed almost 50% of the total removal in the pH range 3-7. Adsorption behavior was dominated by the finer sediment fraction (d transport modeling.

  13. Mineralogy and Microbial Survival During Carbon Sequestration

    Science.gov (United States)

    Santillan, E. U.; Gilbert, K.; Bennett, P.

    2010-12-01

    When CO2 is sequestered in deep saline aquifers, a region of high dissolved CO2 surrounds the supercritical CO2 plume. While microbial life will doubtless be perturbed as a result of the CO2 injection, survival may be possible in the region of high dissolved CO2. Mineralogy of the aquifer may influence which microorganisms survive by providing substrates for lithotrophic microbes and determining the competitiveness of microbes in the subsurface. Iron-rich minerals like hematite, for example, provide a terminal electron acceptor for dissimilatory iron reducing bacteria (DIRB) that is essential for their respiration. Mineral dissolution may also provide toxicity for microbes providing increased concentration of toxic elements like Al in groundwater as a result of feldspar or clay dissolution. We investigated, Shewanella oneidensis MR-1, a model DIRB, grown in the presence of representative minerals found in deep saline aquifers including carbonate minerals, silicate minerals, and clays. Cultures were subjected to 20 to 25 atm of CO2 at 30° C for 2 to 8 hours in modified Parr reactors. Cultures were plated to determine viability after CO2 stress and imaged using environmental scanning electron microscopy (ESEM). Preliminary results show that MR-1 grown in the presence of dolomite and subjected to 20 atm of CO2 for 2 hours results in decreased viability in comparison to cells grown with hematite or no minerals present. This suggests there is selective toxicity with dolomite, possibly due to an increase in dissolved Mg. Additionally, ESEM imaging revealed a change in cell morphology from plump rods to thin, pointy cells after incubating in CO2 for 8 hours at 25 atm. This change in cell morphology may be the result of cell damage due to CO2 stress. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic

  14. Novel Visualization Approaches in Environmental Mineralogy

    Science.gov (United States)

    Anderson, C. D.; Lopano, C. L.; Hummer, D. R.; Heaney, P. J.; Post, J. E.; Kubicki, J. D.; Sofo, J. O.

    2006-05-01

    Communicating the complexities of atomic scale reactions between minerals and fluids is fraught with intrinsic challenges. For example, an increasing number of techniques are now available for the interrogation of dynamical processes at the mineral-fluid interface. However, the time-dependent behavior of atomic interactions between a solid and a liquid is often not adequately captured by two-dimensional line drawings or images. At the same time, the necessity for describing these reactions to general audiences is growing more urgent, as funding agencies are amplifying their encouragement to scientists to reach across disciplines and to justify their studies to public audiences. To overcome the shortcomings of traditional graphical representations, the Center for Environmental Kinetics Analysis is creating three-dimensional visualizations of experimental and simulated mineral reactions. These visualizations are then displayed on a stereo 3D projection system called the GeoWall. Made possible (and affordable) by recent improvements in computer and data projector technology, the GeoWall system uses a combination of computer software and hardware, polarizing filters and polarizing glasses, to present visualizations in true 3D. The three-dimensional views greatly improve comprehension of complex multidimensional data, and animations of time series foster better understanding of the underlying processes. The visualizations also offer an effective means to communicate the complexities of environmental mineralogy to colleagues, students and the public. Here we present three different kinds of datasets that demonstrate the effectiveness of the GeoWall in clarifying complex environmental reactions at the atomic scale. First, a time-resolved series of diffraction patterns obtained during the hydrothermal synthesis of metal oxide phases from precursor solutions can be viewed as a surface with interactive controls for peak scaling and color mapping. Second, the results of

  15. Late Quaternary climate change shapes island biodiversity.

    Science.gov (United States)

    Weigelt, Patrick; Steinbauer, Manuel Jonas; Cabral, Juliano Sarmento; Kreft, Holger

    2016-04-07

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration-extinction dynamics, or as geologically dynamic with biodiversity resulting from immigration-speciation-extinction dynamics influenced by changes in island characteristics over millions of years. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels and caused massive changes in island area, isolation and connectivity, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory. Consequences of these oscillations for present biodiversity remain unassessed. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics.

  16. Mineralogy and thermal properties of clay from Slatina (Ub, Serbia)

    Science.gov (United States)

    Milosevic, Maja; Logar, Mihovil; Kaludjerovic, Lazar; Jelic, Ivana

    2017-04-01

    The "Slatina" deposit, Ub, Serbia was opened in 1965 and represents one of few deposits exploited by "Kopovi" a.d., Ub, company. Deposit is composed of clay layers belonging to Neogene sediments that are widespread transgressive over granitoid rocks of Cer mountain and Paleozoic and Mesozoic sediments. Clay is mostly of illite-montmorillonite-kaolinite type and they are generally used as ceramic materials while some of the layers are used as fire-resistant materials. In this study we present mineralogical and thermal characterization of two samples to determine their application as industrial materials. Chemical and mineral composition was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD) on powder and oriented samples, infrared spectroscopy (IR) and granulometry. Cationic exchange capacity (CEC) and specific surface area (SSA) was determined using spectrophotometry and methylene blue (MB). Thermal properties where determined by gravimetry (120, 350, 600 and 1000 oC) and differential thermal analysis (DTA). Quantitative mineral composition obtained by Rietveld refinement of combined chemical and XRD data shows that the sample 1(SC) is mainly smectite-illite (45%) and kaolinite (14%) clay with 19% of quartz, 10% feldspars and 7% of limonite, while sample 2(SV) is smectite-illite (43%) and kaolinite (11%) clay with 10% of quartz, 15% feldspars and 7% of limonite. Both samples have low content of impurities (carbonate minerals). Medium grain size (μm) goes from 1.02 (SSA = 104 m2/g) for sample 1(SC) to 0.71 (SSA = 117 m2/g) for sample 2(SV) while their CEC is 12.7 and 14.9 mmol/100g for 1(SC) and 2(SV) respectively. IR spectra of the samples shows larger amount of smectite clays with quartz and carbonate minerals for both samples which is in accordance with XRD data. DTA data shows couple of events that are endothermic. First one (100-200 oC) is associated with loss of moisture and constitutive water, second

  17. Scalable Generalization of Hydraulic Conductivity in Quaternary Strata for Use in a Regional Groundwater Model

    Science.gov (United States)

    Jatnieks, J.; Popovs, K.; Klints, I.; Timuhins, A.; Kalvans, A.; Delina, A.; Saks, T.

    2012-04-01

    The cover of Quaternary sediments especially in formerly glaciated territories usually is the most complex part of the sedimentary sequences. In regional hydro-geological models it is often assumed as a single layer with uniform or calibrated properties (Valner 2003). However, the properties and structure of Quaternary sediments control the groundwater recharge: it can either direct the groundwater flow horizontally towards discharge in topographic lows or vertically, recharging groundwater in the bedrock. This work aims to present calibration results and detail our experience while integrating a scalable generalization of hydraulic conductivity for Quaternary strata in the regional groundwater modelling system for the Baltic artesian basin - MOSYS V1. We also present a method for solving boundary transitions between spatial clusters of lithologically similar structure. In this study the main unit of generalization is the spatial cluster. Clusters are obtained from distance calculations combining the Normalized Compression Distance (NCD) metric, calculated by the CompLearn parameter-free machine learning toolkit, with normalized Euclidean distance measures for coordinates of the borehole log data. A hierarchical clustering solution is used for obtaining cluster membership identifier for each borehole. Using boreholes as generator points for Voronoi tessellation and dissolving resulting polygons according to their cluster membership attribute, allows us to obtain spatial regions representing a certain degree of similarity in lithological structure. This degree of similarity and the spatial heterogeneity of the cluster polygons can be varied by different flattening of the hierarchical cluster model into variable number of clusters. This provides a scalable generalization solution which can be adapted according to model calibration performance. Using the dissimilarity matrix of the NCD metric, a borehole most similar to all the others from the lithological structure

  18. The junction of Fensch and Moselle rivers, France; mineralogy and composition of river materials

    Science.gov (United States)

    Montarges-Pelletier, Emmanuelle; Jeanneau, Laurent; Faure, Pierre; Bihannic, Isabelle; Barres, Odile; Lartiges, Bruno S.

    2007-09-01

    The Moselle river flows in the north-east of France, from Vosges Mountains to neighboring countries Luxembourg and Germany. One of its tributaries, the Fensch river, drains a highly industrialized watershed, strongly impacted by mining, smelting and surfacing activities. The objective of this work, part of a general research program on Moselle watershed (Zone Atelier Moselle) was to assess the impact of the polluted Fensch river on the global quality of the Moselle river. For that purpose, water, sediments and suspended particulate matter were sampled in both rivers, upstream and downstream the junction. Four main sampling campaigns were carried out, in winter during a flood event and in spring at low water level. On a first step, mineralogical analyses (XRD and FTIR) and chemical analyses (ICP-MS, ICP-AES), were performed on sediments, suspended particulate matters and filtered waters. Major and trace elements concentrations were obtained on two different granulometric fractions (0-2 mm and 0-50 μm) revealing the enrichment in heavy metals of fine particles. From one collecting campaign to another, seasonal variations could be evidenced on suspended matter composition even though major minerals (calcite, quartz and kaolinite) were always present. Furthermore, spatial variations were evidenced for Fensch and Moselle downstream sediments. Thus, very fine-grained sediments, poorly crystallized, displaying at the same time higher metal concentrations and higher organic matter content than in Fensch river material, were collected downstream, in a low hydrodynamic conditions zone, assumed as a preferential sedimentary zone or even as a placer. Strong correlations could be revealed between iron content and contaminant concentrations, confirming the origin of polluted material.

  19. Fall, mineralogy and chemistry of Nathdwara H6 chondrite

    Directory of Open Access Journals (Sweden)

    V. Agarwal

    2014-05-01

    Full Text Available We report here for the first time the composition and mineralogical studies on a new meteorite, which fell in Dhayala ki Chappar (24°58′N, 73°48′27″E 5 km NW of Nathdwara in south Rajasthan, India, on Dec. 25th, 2012. Mineralogical and compositional studies were carried out on a representative piece of the Nathdwara meteorite sample. The mineralogical composition of the meteorite has been found to be olivine (42−45 vol.%, feldspar (10−15 vol.%, orthopyroxene (23−25 vol.%, troilite (6−8 vol.%, and titanium bearing minerals (6−8 vol.%. Our investigations show that the Nathdwara meteorite belongs to H6 group of ordinary chondrites.

  20. Fall, mineralogy and chemistry of Nathdwara H6 chondrite

    Institute of Scientific and Technical Information of China (English)

    V. Agarwal; G. Parthasarathy; M.S. Sisodia; N. Bhandari

    2014-01-01

    We report here for the first time the composition and mineralogical studies on a new meteorite, which fell in Dhayala ki Chappar (24º58'N, 73º48'27'' E) 5 km NW of Nathdwara in south Rajasthan, India, on Dec. 25th, 2012. Mineralogical and compositional studies were carried out on a representative piece of the Nathdwara meteorite sample. The mineralogical composition of the meteorite has been found to be olivine (42-45 vol.%), feldspar (10-15 vol.%), orthopyroxene (23-25 vol.%), troilite (6-8 vol.%), and titanium bearing minerals (6-8 vol.%). Our investigations show that the Nathdwara meteorite belongs to H6 group of ordinary chondrites.

  1. Impact of mineralogical heterogeneity on reactive transport modelling

    Science.gov (United States)

    Liu, Min; Shabaninejad, Mehdi; Mostaghimi, Peyman

    2017-07-01

    Impact of mineralogical heterogeneity of rocks in reactive modelling is investigated by applying a pore scale model based on the Lattice Boltzmann and Finite Volume Methods. Mass transport, chemical reaction and solid structure modification are included in the model. A two-dimensional mineral map of a sandstone rock is acquired using the imaging technique of QEMSCAN SEM with Energy-Dispersive X-ray Spectroscopy (EDS). The mineralogical heterogeneity is explored by conducting multi-mineral reaction simulations on images containing various minerals. The results are then compared with the prediction of single mineral dissolution modelling. Dissolution patterns and permeability variations of multi-mineral and single mineral reactions are presented. The errors of single mineral reaction modelling are also estimated. Numerical results show that mineralogical heterogeneity can cause significant errors in permeability prediction, if a uniform mineral distribution is assumed. The errors are smaller in high Péclet regimes than in low Péclet regimes in this sample.

  2. Mineralogy of the Culebra Dolomite Member of the Rustler Formation

    Energy Technology Data Exchange (ETDEWEB)

    Sewards, T.; Williams, M.L.; Keil, K. (New Mexico Univ., Albuquerque, NM (USA))

    1991-03-01

    This report characterizes the mineralogy of the Culebra Member of the Rustler Formation based on studies of samples from cores of eight boreholes surrounding the WIPP repository. This investigation has three main goals: to obtain accurate modal compositions of all the samples selected; to investigate both the lateral and vertical variation of the mineralogy of the Culebra unit; and, to characterize water-bearing fracture surfaces in particular detail. The Culebra Dolomite member of the Rustler Formation is mineralogically and texturally heterogeneous, both vertically and horizontally. Although the predominant mineral is dolomite, important constituents of the formation are clay, quartz, gypsum, and calcite. Trace minerals include halite, phyllosilicates of metamorphic origin, feldspar, and pyrite. 24 refs., 90 figs., 27 tabs.

  3. Determinative Mineralogy: An Essential Component of Planetary Exploration

    Science.gov (United States)

    Bish, D. T.; Vaniman, D. T.; Blake, D. F.; Green, J. R.; Johnston, C. T.; Kelly-Serrato, B. A.; Ming, D. W.; Papike, J. J.; Yen, A. S.; Zolensky, M. E.

    2002-08-01

    Mineralogy is a fundamental characteristic of extraterrestrial bodies because different mineral assemblages can be used to characterize present and past conditions of the atmosphere, the surface, the crust, and the deep interior of a planet. Many tools are used in space exploration, and the exploration of extraterrestrial mineralogy is no exception. The tools that are needed include remote observations, in-situ analysis with landed instruments, and analysis of returned samples in laboratories on Earth. In a balanced exploration program, all three sources of data are necessary. Likewise, no one method will provide the information needed to understand the makeup and history of extraterrestrial bodies. This paper is intended as a starting point for the development of truly integrated mineralogic instrumentation efforts that will combine the diverse capabilities of many analytical methods.

  4. Human impact on late Quaternary landscapes in the Central Spanish Pyrenees

    Science.gov (United States)

    Hirsch, F.; Raab, T. A.

    2011-12-01

    Like the Alps in Central Europe the Pyrenees in Southeast Europe are well known for their glacial history. Within the scope of the ongoing research project Post-LGM pedogenesis and geomorphodynamics in the Aragonese Pyrenees, Spain, funded by the Deutsche Forschungsgemeinschaft (DFG), we are studying the landscapes in the Gallego valley and the Aragon valley formed during the late Quaternary period. The aim of this research is to describe and characterize the soil development since the retreat of the valley glaciers from the LGM-moraines which are supposed to have an age of up to 60 ka yrs. To these purposes soil profiles are excavated in sediments and landforms of different ages (LGM to Holocene) and different genesis (glacigenic, glacifluvial, fluvial, gravitational). The soil profiles are arranged as catenas and provide insight into the pedo-stratigraphy of moraines, fluvial terraces, glacis and alluvial fans. Our preliminary results show that besides geogenic process past human land use must be considered as a main trigger of landscape development during the late Holocene. Truncated soil profiles in the backslopes and the correlate sediments of soil erosion burying soil horizons in the footslopes clearly indicate one or even more periods of re-shaping the landforms after deglaciation. Considerable amounts of small charcoal and tile fragments in the translocated sediments hint to an anthropogenic agent. The disturbance in the soil profiles and sediments is visible in the field and by micromorphology. Although 14C and OSL datings on the base of the correlate sediments of soil erosion indicate at least one phase of erosion and redeposition at the end of the 17th century, the onset of afresh pedogenic processes in the correlate sediments of soil erosion indicate young soil formation.

  5. Late Quaternary geology of the Lower Central Plain, Thailand

    Science.gov (United States)

    Sinsakul, Sin

    2000-08-01

    The Lower Central Plain or Chao Phraya Plain, located in the upper Gulf of Thailand, has an average elevation of 2 m above the present mean sea level. It is a fault bounded basin developed in the Plio-Pleistocene epoch. Consequently, the basin has been filled with Quaternary sediment reaching a thickness of almost 2000 m, of which only the upper 300 m is known. The Pleistocene deposits of the Lower Central Plain represent a complex interplay of alluvial, fluvial and deltaic environments of the Chao Phraya River and its tributaries. The upper sequence of sand and stiff clay with iron-oxide concretions on the surface was deposited in a fluviatile environment subjected to a regressive period in the late Pleistocene. The term "Chao Phraya delta" is used to define the landform where the Chao Phraya River interacted with marine processes as the sea level changed during the Holocene transgression. These strata indicated that the Holocene sea reached its maximum height of 4 m above the present mean sea level around 6000 years B.P.; from then on sea level fluctuated until it reached its present level around 1500 years B.P. This complex sea level history has caused the progradation of tidal flat, and tide-dominated delta deposits, consisting of soft marine clay, that covered the Lower Central Plain to an average depth of 15 m in the Bangkok area. The soft marine clay or Bangkok clay is the most important unit in the stratigraphic sequence in terms of land subsidence in the Lower Central Plain. Evidence of coastal erosion is also considerable in the low tidal flat area on the west bank of the Chao Phraya River mouth and adjacent coast.

  6. Quaternary Tectonism in a Collision Zone, Northwest Washington

    Science.gov (United States)

    McCrory, P. A.; Wolf, S. C.; Intelmann, S. S.; Danforth, W. W.; Weldon, R. J.; Blair, J. L.

    2004-12-01

    Kinematic, geodetic, and geologic observations define a region with 6-8 mm/y of north-south contraction between the Columbia River and Vancouver Island. We attribute this contraction to differential forearc-block motion within the Cascadia subduction system where the Oregon Coast Range block is moving northward relative to Vancouver Island. The contraction is accommodated by a combination of distributed uplift in the Olympic Mountains, and faulting along the margins of the Coast Range and Vancouver Island blocks. The tide gauge at Neah Bay, which records one of the highest rates of uplift anywhere along the Cascadia subduction margin, suggests that a significant portion of this north-south contraction occurs between the northern Olympic Peninsula and Vancouver Island. The northwest-trending Calawah fault, extending from Makah Bay eastward to near Lake Crescent, appears to mark the modern boundary between the Olympic Mountains block and the Vancouver Island block in northwestern Washington. Onshore, the 80+ km-long Calawah fault displaces late Quaternary glacial sediments and geodetic uplift rates increase abruptly across the fault zone. Offshore in Makah Bay, new multibeam, sidescan-sonar, and high-resolution seismic reflection data image a complex, multi-strand fault zone that offsets the seafloor and moves Cape Flattery rocks seaward. Two parallel, northwest-trending fault strands bound a down-dropped block that in turn terminates along a northward-trending anticlinal fold and thrust fault. These data suggest that the Calawah fault zone currently accommodates contraction both by uplift and by seaward translation of rocks north of the forearc-block boundary. Our geologic mapping in the Cape Flattery area indicates that differential block motion is accommodated by a combination of crustal uplift, folding, and left-lateral, strike-slip faulting.

  7. Quaternary deformation around the Palo Negro area, Pampa Norte, Argentina

    Science.gov (United States)

    Brunetto, E.; Iriondo, M.; Zamboni, L.; Gottardi, G.

    2010-04-01

    The Pampa Norte region is a great plain characterized by low slopes and accumulation of hundreds of meters of thick loose sediments. A high morphostructure denominated San Guillermo block stands out in the central plain, the Tostado-Selva scarp forming its western boundary. It is located in an intraplate setting characterized by low tectonic activity. However recent uplift can be inferred by means of terrain analysis and the sedimentology of the Palo Negro Fm. Pond deposits (Palo Negro Fm.) observed in the scarp suggest topographic inversion during the Late Quaternary in the Palo Negro area. The morphology indicates that the deformation was widely distributed, forming a gentle (ca. 5 m amplitude and 13 km wavelength) asymmetric fold. Low sinuosity lineaments located in the base of the scarp, coincident with knick points in the topographic profile, can be interpreted as the projection of tip-lines by high-angle fault-propagation. This geometry is compatible with reverse kinematics on blind faults. A deformation style with reactivation of pre-existing faults is consistent with structural observations. Seismic reflectors suggest the presence of Cretaceous high-angle normal faults, and the orientation of lineaments is similar to the orientation of the graben systems and transverse accommodation zones originated during the opening of the South Atlantic Ocean. One OSL dating of 67.4 ± 5.1 kyr B.P (from Palo Negro Fm. supposed as deposited on a flat plain floor) and a height difference of 9.5 m measured in the Tostado-Selva scarp account for an averaged uplift rate of 0.14 mm/year.

  8. Notas de mineralogía parte I

    OpenAIRE

    Henao Vásquez, Martha

    1987-01-01

    Resumen: El presente trabajo, llamado "Notas de mineralogía, parte I", es un resumen y recopilación de temas de varios textos, notas y de la misma experiencia docente. Existen dos razones que motivan la elaboración de estas notas, y son: en primer lugar, un requisito parcial para la promoción a la categoría de Profesor Asistente de la Facultad de Ciencias, Universidad Nacional, y en segundo, por ser la mineralogía una asignatura esencial en programas tales como geología, ingeniería de geol...

  9. MINERALOGICAL FEATURES OF ULTRAMAFIC HYPOXENOLITHS IN ALKALI-RICH PORPHYRY

    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; YANG Zhengxi; LIU Jiaduo; ZHANG Chengjiang; WU Dechao; LI Youguo

    2003-01-01

    Ultramafic hypoxenoliths found in the alkali-rich porphyry in the Liuhe Village, Heqing, Yunnan,China, are of great significance in understanding the origin and evolution of the porphyry. This paper discusses the mineralogical features of the hypoxenoliths. It shows that the xenoliths are characterized by the upper mantle rocks modified to certain extent by the enriched mantle fluid metasomatism in the mantle environment, with the enriched mantle property of Iow-degree partial melting. This constitutes the important mineralogical evidence for the petrogenesis and mineralization of alkali-rich porphyry.

  10. Mineralogy: a modern approach to teaching a traditional discipline

    Science.gov (United States)

    Cook, G. W.

    2011-12-01

    Mineralogy has traditionally been a primary component in undergraduate geoscience curriculum. In recent years, there has been a trend in which mineralogy and petrology have been combined into Earth Materials courses. This is unfortunate as these disciplines each have much to offer students, and content once considered essential is eliminated out of necessity. Mineralogy is still fundamental to students' understanding of the Earth and Earth processes. Using a modern approach to time-honored concepts, I teach a quarter-long Introductory Mineralogy class offered through the Scripps Institution of Oceanography at the University of California, San Diego. Student evaluations of this course unequivocally indicate a high degree of learning and interest in the material, confirming that mineralogy continues to be a valuable class into the 21st century. While much of the content remains similar to what has been taught over the last century, my strategy involves a well-balanced approach to old and new. The first third of the course is background including the relevance of mineralogy, crystal chemistry, and crystallography; the second third of the course is systematic mineralogy using the Dana system; the last third of the course is devoted to understanding optical mineralogy, using modern analytical equipment such as XRD and SEM, and learning to use the petrographic microscope. Throughout the quarter, a strong emphasis is placed on the importance of hand-sample identification. Field work, traditionally not emphasized in mineralogy courses, has been re-introduced to the curriculum. I use modern technology to facilitate and support student learning. A lecture-based approach is employed with carefully crafted and organized PowerPoint presentations. PowerPoint lectures can be effective and highly engaging. The key is to ensure that the lectures are not overly reliant on text, instead relying on diagrams, charts, photos, and embedded media such as 3-D animations (ex. to teach

  11. Suggested terminology for Quaternary dating methods

    Science.gov (United States)

    Colman, Steven M.; Pierce, K.L.; Birkeland, P.W.

    1987-01-01

    Classification of Quaternary dating methods should be based on the level of quantitative information and the degree of confidence contained in the age estimates produced by the dating methods. We recommend the use of the terms numerical-age, calibrated-age, relative-age, and correlated-age to describe these levels. We also classify dating methods by type into sideral, isotopic, radiogenic, chemical and biological, geomorphic, and correlation methods. The use of "absolute" is inappropriate for most dating methods, and should be replaced by "numerical." The use of "date" should be minimized in favor of "age" or "age estimate." We recommend use of the abbreviations ka and Ma for most ages; calender dates can be used where appropriate and yr B.P. can be used for radiocarbon ages. ?? 1987.

  12. Quaternary ammonium compounds – New occupational hazards

    Directory of Open Access Journals (Sweden)

    Agnieszka Lipińska-Ojrzanowska

    2014-10-01

    Full Text Available Quaternary ammonium compounds (QACs, quats belong to organic ionic chemical agents which display unique properties of both surfactants and disinfectants. Their wide distribution in the work environment and also in private households brings about new occupational hazards. This paper reviews reports about the health effects of QACs. QACs could play a role of sensitizers and irritants to the skin and mucous membranes. It is suspected that particular QACs can display an immunologic crossreactivity between each other and with other chemical compounds containing ammonium ion, such as muscle relaxants widely used in anesthesia. They may promote the development of airway allergy, however, the background mechanisms are still unclear and need to be further investigated. Until now, a few cases of occupational asthma induced by QACs have been described and their involvement in contact dermatitis has been documented. The possibility of anaphylaxis due to QACs cannot be excluded as well. Med Pr 2014;65(5:675–682

  13. Biosedimentology of Quaternary stromatolites in intertropical Africa

    Science.gov (United States)

    Casanova, J.

    Mineralizations of microbial origin constitute a non-negligeable part of Quaternary limestones in intertropical Africa. Stromatolites have colonized a wide range of environments corresponding to different hydroclimatic situations: travertines in fluviatile environments, oncolites in flood plains, encrustations in sebkha areas and shorelines of deep, fresh water lakes. The developed morphologies represent a complete catalogue of the microbial carbonated mineralizations: oncolites, chemneys, pool-rim dams, biocherms, planar or cylindrical encrustations. The building organisms may be either pure bacterial colonies (hydrothermal and lacustrine environments), cyanophyte associations (fluviatile and lacustrine environments) or complex microbial biocoenoses. Stromatolites have recorded the hydrologic, climatic and sedimentologic evolution of the continental environment in intertropical Africa for the past 240 000 years.

  14. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

    Two indicators of the hydropathicity of small solutes are introduced and tested by molecular dynamics simulations. These indicators are defined as probabilities of the orientation of water molecules\\' dipoles and hydrogen bond vectors, conditional on a generalized distance from the solute suitable for arbitrarily shaped molecules. Using conditional probabilities, it is possible to distinguish features of the distributions in close proximity of the solute. These regions contain the most significant information on the hydration structure but cannot be adequately represented by using, as is usually done, joint distance-angle probability densities. Our calculations show that using our indicators a relative hydropathicity scale for the interesting test set of the quaternary ammonium cations can be roughly determined. © 2010 American Chemical Society.

  15. Energy consumption maps for quaternary distillation sequences

    DEFF Research Database (Denmark)

    Gomez-Castro, F.I.; Ramírez-Vallejo, N.E.; Segovia-Hernandez, J.G.

    2016-01-01

    of the solutions space. For the separation of ternary mixtures, Tedder and Rudd (1978) presented a composition map for which thermally coupled systems allowed energy savings. However, the scenario is different for quaternary mixtures, since no similar information is available. Therefore, in this work, energy...... be generated for the separation of multicomponent mixtures. This fact is an advantage, since a wide portfolio of alternatives can be used to separate a specific mixture; however, this is also a disadvantage since a lot of alternatives must be explored in order to find the optimal one. The optimal configuration......, for a given mixture, depends on the nature of the mixture, usually quantified for ternary mixtures through the ease of separation index (ESI), and also on the feed composition. As can be noticed, the size of the design and optimization problem increases when these variables are considered in the generation...

  16. Thermal conductivity of sedimentary rocks - selected methodological, mineralogical and textural studies

    Energy Technology Data Exchange (ETDEWEB)

    Midttoemme, Kirsti

    1997-12-31

    The thermal conductivity of sedimentary rocks is an important parameter in basin modelling as the main parameter controlling the temperature within a sedimentary basin. This thesis presents measured thermal conductivities, mainly on clay- and mudstone. The measured values are compared with values obtained by using thermal conductivity models. Some new thermal conductivity models are developed based on the measured values. The values obtained are less than most previously published values. In a study of unconsolidated sediments a constant deviation was found between thermal conductivities measured with a needle probe and a divided bas apparatus. Accepted thermal conductivity models based on the geometric mean model fail to predict the thermal conductivity of clay- and mudstone. Despite this, models based on the geometric mean model, where the effect of porosity is taken account of by the geometric mean equation, seem to be the best. Existing models underestimate the textural influence on the thermal conductivity of clay- and mudstone. The grain size was found to influence the thermal conductivity of artificial quartz samples. The clay mineral content seems to be a point of uncertainty in both measuring and modelling thermal conductivity. A good universal thermal conductivity model must include many mineralogical and textural factors. Since this is difficult, different models restricted to specific sediment types and textures are suggested to be the best solution to obtain realistic estimates applicable in basin modelling. 243 refs., 64 figs., 31 tabs.

  17. Late Quaternary temperature change velocity in Mesoamerica

    Science.gov (United States)

    Correa-Metrio, A.; Lozano, S.; Sosa-Nájera, S.; Bush, M. B.

    2013-05-01

    Quaternary climate has been highly variable, and yet few quantitative continental reconstructions are available for tropical areas. Quantitative records of temperature change during the Quaternary are especially relevant for putting modern climate change into a historic context. Within this perspective, two aspects are of singular relevance: i) Identifying and quantifying past climatic variability, and ii) Providing a means to estimate the seed at which climate change happened in the past. Here we show temperature reconstructions and temperature change velocity calculations for two locations in northern tropical America. Temperature reconstruction was based on two sedimentary records form Lake Chalco (30,000 years), central Mexican highlands, and Lake Petén-Itzá, Guatemalan lowlands (86,000 years). Temperature reconstruction was based on the analysis of fossil pollen on the light of pollen-temperature transfer functions. These functions were calibrated through an extensive survey of modern pollen samples covering an elevational gradient from 0 to 4,218 m asl. Derived temperature profiles show a parallel long-term trend and a similar cooling of approximately 5 oC during the Last Glacial Maximum in the lowlands and highlands of Mexico and Guatemala. Using a digital elevation model, we ere able to reconstruct the velocity at which isotherms displaced to produce the observed temperature anomalies. Spatial velocities of temperature change in the studied areas were at least four times slower than values reported for the last 50 years, but also at least twice as fast as those obtained from recent models. This study demonstrates that modern temperature change has no precedent within the last 86,000 years, but also that tropical climate has been more variable than it has been assumed to date.

  18. Origin, Extent, and Thickness of Quaternary Geologic Units in the Willamette Valley, Oregon

    Science.gov (United States)

    O'Connor, Jim E.; Sarna-Wojcicki, Andrei M.; Wozniak, Karl C.; Polette, Danial J.; Fleck, Robert J.

    2001-01-01

    Stratigraphic and chronologic information collected for Quaternary deposits in the Willamette Valley, Oregon, provides a revised stratigraphic framework that serves as a basis for a 1:250,000-scale map, as well as for thickness estimates of widespread Quaternary geologic units. We have mapped 11 separate Quaternary units that are differentiated on the basis of stratigraphic, topographic, pedogenic, and hydrogeologic properties. In summation, these units reflect four distinct episodes in the Quaternary geologic development of the Willamette Valley: 1) Fluvial sands and gravels that underlie terraces flanking lowland margins and tributary valleys were probably deposited between 2.5 and 0.5 million years ago. They are the oldest widespread surficial Quaternary deposits in the valley. Their present positions and preservation are undoubtedly due to postdepositional tectonic deformation - either by direct tectonic uplift of valley margins, or by regional tectonic controls on local base level. 2) Tertiary and Quaternary excavation or tectonic lowering of the Willamette Valley accommodated as much as 500 m (meters) of lacustrine and fluvial fill. Beneath the lowland floor, much of the upper 10 to 50 m of fill is Quaternary sand and gravel deposited by braided channel systems in subhorizontal sheets 2 to 10 m thick. These deposits grade to gravel fans 40 to 100 m thick where major Cascade Range rivers enter the valley and are traced farther upstream as much thinner valley trains of coarse gravel. The sand and gravel deposits have ages that range from greater than 420,000 to about 12,000 years old. A widely distributed layer of sand and gravel deposited at about 12 ka (kiloannum, thousands of years before the present) is looser and probably more permeable than older sand and gravel. Stratigraphic exposures and drillers' logs indicate that this late Pleistocene unit is mostly between 5 and 20 m thick where it has not been subsequently eroded by the Willamette River and its

  19. Quaternary transgressive and regressive depositional sequences in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    LIUZhenxia; YINPing; XIONGYingqian; S.Beme; A.Trentesaux; LIChaoxin

    2003-01-01

    Based on the interpretation more than 4000 km sparker single channel seismic profiles and the comparison with Borehole DZQ4 on the outer shelf of the East China Sea (ECS),the seismic sequences,sedimentary facies and paleo-sedimentary environment are studied to establish the chronology framework and discuss the Quaternary transgressive and regressive sequences of the ECS shelf as well as their response to glacio-eustatic sea-level changes.The sea level of the ECS fluctuated with global climate changes in the Quaternary.During the sea level rise,the pacific tidal wave impacted actively on the ECS continental shelf and the reciprocating tidal currents in NW-SE direction formed tidal sand ridges,which represent large transgressive deposits visible on the seismic profiles.In response to sea level fall,the Yangtze River deltas prograded seaward and built massive subaqueous deltas to form regressive sequences on the seismic profiles.Alternative transgression and regression sequences were vertically distributed on the ECS shelf with the frequent eustacy in the Quaternary.The gentle slope of the ECS shelf makes it possible for the coastline to migrate hundreds of kilometers forth and back on the shelf because of tens of meters sea level changes,in the meanwhile,the Yangtze River discharged large amounts of sediments into the ECS resulting in large-scale subaqueous deltas and tidal sand ridges.There have developed 3 stages of tidal sand ridges and 4 stages of deltas on the ECS shelf since oxygen isotope stage 8.

  20. Transient Quaternary erosion and tectonic inversion of the Northern Range, Trinidad

    Science.gov (United States)

    Arkle, Jeanette C.; Owen, Lewis A.; Weber, John; Caffee, Marc W.; Hammer, Sarah

    2017-10-01

    Cosmogenic 10Be measured in sediments from Northern Range catchments on the island of Trinidad reveals low millennial-scale rates of erosion (average 40 mm/ka) that increase roughly eightfold, from 11 to 92 mm/ka, eastward across the mountain range. These results, in conjunction with an analysis of mountain morphometrics, are consistent with Quaternary east-side-up tilting of the Northern Range, which has occurred recently ( 100 ka). The highest millennial-scale erosion rates coincide spatially with Quaternary east-side surface uplift (albeit not in magnitude), high modern rainfall rates, low topographic relief, and convex longitudinal stream profiles, indicating transient Quaternary erosion. We interpret that hillslope adjustment and erosion of the Northern Range is buffered from climatic and tectonic forcings by dense tropical vegetation cover, thick saprolite, and porous regolith. Compared with longer-term, thermochronology exhumation rates, we document that an order of magnitude deceleration of and reversal in the locus of erosion and exhumation has occurred during the Pliocene to the Holocene. We suggest that these combined data sets highlight distinct syn- and post-collisional phases of Northern Range development that are related to a major change in relative Caribbean-South American plate motion from oblique convergence to transform motion. Oblique collision during the mid-Miocene likely caused relatively higher rates of and asymmetric exhumation of the Northern Range. Post-collisional mountain-scale tilting is likely caused by a combination of crustal extension in the Gulf of Paria and by deep subsurface lithospheric detachment processes that drives dynamic topography.

  1. Quaternary Logic and Applications Using Multiple Quantum Well Based SWSFETs

    Directory of Open Access Journals (Sweden)

    P. Gogna

    2012-11-01

    Full Text Available This paper presents Spatial Wavefunction-Switched Field-Effect Transistors (SWSFET to implement efficient quaternary logic and arithmetic functions. Various quaternary logic gates and digital building blocks are presented using SWSFETs. In addition, arithmetic operation with full adder using novel logic algebra is also presented. The SWSFET based implementation of digital logic, cache and arithmetic block results in up to 75% reduction in transistor count and up to 50% reduction in data interconnect densities. Simulations of quaternary logic gates using the BSIM equivalent models for SWSFET channels are also described.

  2. Antimicrobial Polymeric Materials with Quaternary Ammonium and Phosphonium Salts

    Directory of Open Access Journals (Sweden)

    Yan Xue

    2015-02-01

    Full Text Available Polymeric materials containing quaternary ammonium and/or phosphonium salts have been extensively studied and applied to a variety of antimicrobial-relevant areas. With various architectures, polymeric quaternary ammonium/phosphonium salts were prepared using different approaches, exhibiting different antimicrobial activities and potential applications. This review focuses on the state of the art of antimicrobial polymers with quaternary ammonium/phosphonium salts. In particular, it discusses the structure and synthesis method, mechanisms of antimicrobial action, and the comparison of antimicrobial performance between these two kinds of polymers.

  3. Assessment by X-ray diffraction the process of bentonite organophilization using a different quaternary ammonium salts; Avaliacao por difracao de raios X do processo de organofilizacao de uma bentonita utilizando diferentes sais quaternarios de amonio

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.A. da; Rosario, J.A. do; Lima, R.B.; Milioli, C.C.; Gusatti, M.; Linhares, R.H.; Kuhnen, N.C.; Riella, H.G., E-mail: lasqmc@hotmail.co [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Campus Reitor Joao David Ferreira Lima; Cumbane, A.J. [Universidade Eduardo Mondlane (UEM), Maputo (Mozambique)

    2010-07-01

    The process was conducted in an organophilization Bentonite originated from the Company of Industrial Minerals of Mozambique Ltd. (Mimoc). The transformation of bentonite organophilic clay were performed in laboratory procedures that aim to mechanochemical exchange of Na{sup +} and Ca{sup 2+} from the interlayer space of clay minerals by cations of quaternary ammonium salts. In this study we used two types of salts, which are: the cetyl trimethyl ammonium chloride and alkyl dimethyl benzyl ammonium chloride at different concentrations (30, 50, 80, 100 meq/100 g clay). The natural bentonite and organophilic clay samples were characterized by X-ray diffraction (XRD) to obtain the mineralogical constituents and analysis phases of the increase in interlayer distance confirming the incorporation of quaternary ammonium salts in the structure of clays. (author)

  4. Applied Mineralogy: A Critical Review and 5-Year Plan for Its Strategic Use within Teck

    OpenAIRE

    Nichola Ann McKay

    2015-01-01

    A strategic business case analysis and five-year plan are presented here for the Teck Applied Mineralogy group in Trail, British Columbia. Applied mineralogy is a key technical competency for Teck Resources that adds value in the fields of process mineralogy supporting optimization at the mining operations, and in ore characterization supporting evaluation of greenfield and brownfield properties. This 2016-2020 business plan for the applied mineralogy group is cognisant of the current mining ...

  5. CONTRAST IN CLAY MINERALOGY AND THEIR EFFECT ON ...

    African Journals Online (AJOL)

    a

    Petroleum Operations Department, Ministry of Mines and Energy, P.O. Box 486, Kotebe ... mineralogy impact on porosity permeability and other reservoir ..... iron is present as ferric oxides and enters into the crystal lattice of the clay or makes ...

  6. Mineralogy and geochemistry of density-separated Greek lignite fractions

    NARCIS (Netherlands)

    Iordanidis, A.; Doesburg, van J.D.J.

    2006-01-01

    In this study, lignite samples were collected from the Ptolemais region, northern Greece, homogenized, crushed to less than I nun, and separated in three density fractions using heavy media. The mineralogical investigation of the density fractions showed a predominance of pyrite in the light fractio

  7. Mineralogy and geochemistry of bauxite and bentonite deposits from Mozambique

    NARCIS (Netherlands)

    Dos Muchangos, A.C.

    2000-01-01

    Results of mineralogical and geochemical studies of bauxites, kaolinitic clays and bentoniteS from Mozambique are presented in this thesis. The bauxite and kaolinitic clay deposits in Penhalonga area (in the central western part of Mozambique) are associated with Precambrian magmatic rocks and the b

  8. Mineralogy and geochemistry of bauxite and bentonite deposits from Mozambique

    NARCIS (Netherlands)

    Dos Muchangos, A.C.

    2000-01-01

    Results of mineralogical and geochemical studies of bauxites, kaolinitic clays and bentoniteS from Mozambique are presented in this thesis. The bauxite and kaolinitic clay deposits in Penhalonga area (in the central western part of Mozambique) are associated with Precambrian magmatic rocks and the b

  9. Mineralogical and geochemical study of mud volcanoes in north ...

    African Journals Online (AJOL)

    AJL

    Key word: Mud volcano, clay mineralogy, geochemistry, mud breccias, North Moroccan Atlantic margin. INTRODUCTION .... The geochemical analysis of the metals shows a high Ti ..... smectite evolved into an illite, or because the initial source is not .... Pinheiro LM, Kopf A, Boetius A (2006): Microbial methane turnover at.

  10. Environmental factors of urinary stones mineralogy, Khouzestan Province, Iran

    Science.gov (United States)

    Zarasvandi, Alireza; Carranza, E. J. M.; Heidari, Majid; Mousapour, Esmaeil

    2014-09-01

    Urinary stone diseases in the Khouzestan province (southwest Iran) are growing in number and it required extensive studies on various factors of the urinary stones formation in this province. In this research, in addition to distribution of urinary stones in different areas of province, the role of bioenvironmental (race), climate (temperature) and geology (water hardness) factors in urinary stones diversity has been studied. Mineralogical studied using X-ray diffraction showed that uricite and whewellite are the most frequency mineral phases. Struvite, Cystine, hydroxyapatite, weddellite, and Niahite can be observed as urinary stones, too. These data show that the urinary stone in the Khouzestan province can divide into 7 groups: calcium oxalate, phosphate, calcium oxalate/ phosphate, Urate, Urate/calcium, Urate/calcium oxalate/phosphate, Cystine/calcium oxalate. Also the results which attained from temperature effect investigation on the mineralogy of urinary stones, confirms that from Mediterranean sub-humid climates (northeastern area) to warm and dry climates (south and southwest area), calcium oxalate stones and urate stones concentration decreases and increases respectively. Comparison of data related to the drinking water hardness and mineralogy of urinary stones in different areas of Khouzestan province show that the combination of drinking water (especially water hardness) affects mineralogy of urinary stones in some areas (such az Ramhormoz and Hendijan). Finally, the data suggest that frequency of calcium oxalate in women is more than that of men. Moreover, there is direct relationship between the age (>45 years) and the increase in frequency of Urate minerals.

  11. Variations in the Fe mineralogy of bright Martian soil

    Science.gov (United States)

    Murchie, Scott; Mustard, John; Erard, Stephane; Geissler, Paul; Singer, Robert

    1993-01-01

    Bright regions on Mars are interpreted as 'soil' derived by chemical alteration of crustal rocks, whose main pigmentary component is ferric oxide or oxyhydroxide. The mineralogy and mineralogic variability of ferric iron are important evidence for the evolution of Martian soil: mineralogy of ferric phases is sensitive to chemical conditions in their genetic environments, and the spatial distributions of different ferric phases would record a history of both chemical environments and physical mixing. Reflectance spectroscopic studies provide several types of evidence that discriminate possible pigmentary phases, including the position of a crystal field absorption near 0.9 microns and position and strengths of absorptions in the UV-visible wavelength region. Recent telescopic spectra and laboratory measurements of Mars soil analogs suggest that spectral features of bright soil can be explained based on a single pigmentary phase, hematite (alpha-Fe2O3), occurring in both 'nanophase' and more crystalline forms. Here we report on a systematic investigation of Martian bright regions using ISM imaging spectrometer data, in which we examined spatial variations in the position and shape of the approximately 0.9 microns absorption. We found both local and regional heterogeneities that indicate differences in Fe mineralogy. These results demonstrate that bright soils do not represent a single lithology that has been homogenized by eolian mixing, and suggest that weathering of soils in different geologic settings has followed different physical and chemical pathways.

  12. Models as an Aid to Courses in Crystallography and Mineralogy.

    Science.gov (United States)

    Brady, K. T.

    1983-01-01

    Three models used in teaching crystallography/mineralogy at the University of Technology (Papua, New Guinea) are described. These include stereographic projection model, optical indicatrix models for Istropic/Anisotropic minerals, and model showing effect of anisotropic minerals under crossed polars. Photographs of the models are also included.…

  13. Mineralogy and geochemistry of density-separated Greek lignite fractions

    NARCIS (Netherlands)

    Iordanidis, A.; Doesburg, van J.D.J.

    2006-01-01

    In this study, lignite samples were collected from the Ptolemais region, northern Greece, homogenized, crushed to less than I nun, and separated in three density fractions using heavy media. The mineralogical investigation of the density fractions showed a predominance of pyrite in the light fractio

  14. Evolución tectónica de la fosa de Loncopué: Estructura del depocentro cuaternario del Huecú y su relación con la sedimentación y el volcanismo Tectonic evolution of the Loncopué trough: Structure of the Quaternary Huecú depocenter and its relation to the sedimentation and volcanism

    Directory of Open Access Journals (Sweden)

    Emilio A. Rojas Vera

    2009-04-01

    Full Text Available El depocentro del Huecú constituye un depocentro alojado en el sector central del retroarco en la fosa de Loncopué. Su relleno de carácter volcánico, volcaniclástico, fluvial y lacustre, muestra una estrecha relación con la actividad tectónica que le diera origen. Los diferentes pulsos de efusión mayormente de composición basáltica reflejan la recurrencia de la actividad tectónica asociada a fallamiento extensional y al desarrollo de fisuras tensionales. A partir de métodos potenciales se ha podido verificar que el basamento de las secuencias terciarias participa de la deformación extensional que afectó a la zona durante los últimos 5 Ma. Asimismo rasgos neotectónicos en secuencias volcánicas cuaternarias sugieren la persistencia de los mecanismos de subsidencia en esta cuenca. Estas fallas se encuentran directamente relacionadas con la segmentación inferida del basamento a partir de la gravimetría y magnetometría. La inundación histórica de la zona a partir del endicamiento del río Agrio durante un pulso de eruptividad fisural de la cuenca, demuestra la alta probabilidad de que erupciones en el área del retroarco se repitan en el futuro. El reconocimiento de las áreas anegadas correspondientes a las últimas inundaciones del depocentro del Huecú permite estimar el alcance de estos procesos localizados en el retroarco de Neuquén asociados a tectónica activa y sismicidad.The Huecú basin is located at the central part of the large Loncopué retroarc trough. Its volcanic, volcaniclastic, lacustrine and fluvial filling is directly related to neotectonic activity in the area. The basaltic eruptions are reflecting different pulses associated with the development of extensional faults and tensional fractures. Geophysical potential methods have identified basement involvement in the extensional deformation that affected the Tertiary sequences of the area during the last 5 Mys. Neotectonic features in Quaternary volcanic

  15. Paleoclimatic, paleovegetational and provenance change in the Ganga Plain during the late Quaternary

    Indian Academy of Sciences (India)

    Shailesh Agrawal; Prasanta Sanyal; Melinda K Bera; Jitendra K Dash; Srinivasan Balakrishnan

    2013-08-01

    Present study aims at reconstructing the paleomonsoonal rainfall, paleovegetation and provenance change during the late Quaternary. Towards this, Bhognipur core, collected from the southern Ganga Plain, have been sampled for soil carbonate (SC) and soil. The 18O values of SC (18OSC) range from −7.6 to −4.9‰. The variations in 18OSC values suggest that during the late Quaternary, the monsoon intensified during MIS 3 and MIS 1 and the maximum lowering of rainfall intensity is observed during MIS 2. The 13C value of SC (13CSC), organic matter dispersed in the soil (13CSOM) and occluded in the carbonate nodules (13CNOM) ranges from −4.1 to +1.4‰, −25.6 to −16.3‰, and −27.7 to −25.0‰, respectively, implies mixed C3–C4 vegetation over the Ganga Plain. Variations in 13CSOM and 13CNOM values at same depth imply preservation problem of pristine organic matter signature. Therefore, it is important to assess the preservation of residual organic matter before using it for paleovegetational reconstruction. The monsoon-vegetation relationship indicates that relative abundances of C3–C4 vegetation were mainly driven by variations in monsoonal rainfall intensity. Using 87Sr/86Sr in SC, we show that the Himalayan river was supplying sediments in the southern part of the Ganga Plain during MIS 3.

  16. Pre-Wisconsinan mammals from Jamaica and models of late Quaternary extinction in the greater Antilles

    Science.gov (United States)

    MacPhee, R. D. E.; Ford, Derek C.; McFarlane, Donald A.

    1989-01-01

    The vertebrate fauna recovered from indurated conglomerates at Wallingford Roadside Cave (central Jamaica) is shown to be in excess of 100,000 yr old according to uranium series and electron spin resonance dating. The Wallingford local fauna is therefore pre-Wisconsinan in age, and Roadside Cave is now the oldest radiometrically dated locality in the West Indies containing identifiable species of land mammals. In the absence of a good radiometric record for Quaternary paleontological sites in the Caribbean, there is no satisfactory basis for determining whether most extinct Antillean mammals died out in a "blitzkrieg"-like event immediately following initial human colonization in the mid-Holocene. Fossils of Clidomys (Heptaxodontidae, Caviomorpha), the giant Wallingford rodent, have never been found in situ in sediments of demonstrably Holocene age, and its extinction may antedate the middle Holocene. This is also a possibility for the primate Xenothrix mcgregori, although its remains have been found in loose cave earth. A major, climate-driven bout of terrestrial vertebrate extinction at about 14,000-12,000 yr B.P. has been hypothesized for the West Indies by G. Pregill and S. L. Olson ( Annual Review of Ecology and Systematics12, 75-98, 1981), but at present there is nothing to connect the disappearance of Clidomys with this event either. Quaternary extinctions in the Caribbean may prove to be of critical significance for evaluating the reality of New World blitzkrieg, but not until an effort is mounted to constrain them rigorously using modern radiometric approaches.

  17. Late Quaternary relative sea level in Southern California and Monterey Bay

    Science.gov (United States)

    Reynolds, Laura C.; Simms, Alexander R.

    2015-10-01

    Few records of late Quaternary relative sea level (RSL) are available for the Pacific coast of North America south of San Francisco Bay, a region where RSL data would be particularly useful for constraining vertical rates of tectonic motion. This paper provides the first regional, uplift-corrected late Quaternary RSL history for southern California derived from a compilation of 132 previously published and unpublished radiocarbon ages from nearshore, estuarine, and freshwater deposits in sediment cores from coastal southern California. We also provide a local, uplift-corrected RSL history for Monterey Bay, central California, generated from 48 radiocarbon ages from Elkhorn Slough and surrounding environments. Our resulting compilations show rapid sea-level rise from 15 ka which begins to decelerate to present mean sea level (PMSL) between 6 and 8 ka. Late Holocene (Bay in central California. Both rates of late Holocene RSL rise calculated are lower than recent RSL rates from southern California (˜1.61 ± 0.34 to 2.4 ± 1.04 mm a-1) and Monterey Bay (1.49 ± 0.95 mm a-1), derived from uplift-corrected, 20th century tide gauge data. This new RSL data fills geographical gaps in relative sea-level histories, as well as provides important datums for local tectonic processes.

  18. Palinomorfos de fungos e criptógamas em sedimentos quaternários de duas matas com Araucária, Planalto leste do Rio Grande do Sul, Brasil Palynomorphs of fungi and cryptogams in Quaternary sediments from two Araucaria forests, Eastern Plateau of Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Caroline Scherer

    2008-03-01

    Full Text Available Pólen, esporos e demais palinomorfos preservados em sedimentos são material de referência básico em estudos paleoambientais. A presente pesquisa tem como objetivo apresentar a taxonomia de palinomorfos correspondentes a fungos e criptógamas contidos em sedimentos do interior de duas matas com Araucária do Planalto leste do Rio Grande do Sul e, assim, fornecer subsídios para reconstituições paleoambientais na região. A análise envolveu amostras de dois perfis sedimentares holocênicos de São Francisco de Paula (perfil 1, Alpes de São Francisco, 132 cm; perfil 2, Banhado Amarelo, 101 cm, coletados com o Amostrador de Hiller. O processamento químico das amostras seguiu o método padrão, com HCl, HF, KOH, acetólise e montagem das lâminas em gelatina-glicerinada. A análise foi realizada em microscopia óptica. São apresentados palinomorfos de oito fungos, seis algas, cinco briófitos e 19 pteridófitos. A descrição de cada material é acompanhada de ilustrações e, sempre que possível, de dados ecológicos do organismo de origem. A grande quantidade de palinomorfos distintos, bem preservados nos sedimentos, mostra a potencialidade deste material em oferecer informações ambientais relevantes, junto com grãos de pólen, no estudo da gênese e expansão da mata com Araucária.Pollen, spores and other palynomorphs preserved in sediments are basic reference material for palaeoenvironmental studies. The aim of this research is to present the taxonomy of fungal and cryptogamic palynomorphs contained in sediments from two Araucaria forests on the Eastern Plateau of Rio Grande do Sul, thus contributing to palaeoenvironmental reconstitution in the region. The analysis involved samples from two Holocene sedimentary profiles from São Francisco de Paula (profile 1, Alpes de São Francisco, 132 cm; profile 2, Banhado Amarelo, 101 cm, collected with a Hiller Sampler. Chemical processing of the samples followed standard methodology, using

  19. Reconstruction of the palaeoenvironment using biomarkers and clay mineralogy in loess deposits of northern Iran

    Directory of Open Access Journals (Sweden)

    A. Shahriari

    2016-10-01

    Full Text Available Introduction: Knowledge about palaeoenviroment and palaeovegetation provides information about how vegetation reacts on climate fluctuations in the past, what will help understanding current and future developments caused by e.g. climate change. Northern Iranian Loess-Plateau forms a strongly dissected landscape with steeply sloping loess hills. This loess record reflects numerous cycles of climate change and landscape evolution for the Middle to Late Quaternary period. therefore, this study was done for reconstruction of palaeoenvironment (climate and vegetation in loess-palaeosol sequences in northern Iran. Therefore, this study aims at a preliminary reconstruction of palaeovegetation and palaeoenvironment, in loess-palaeosol sequences along a cliomosequnce in Northern Iran. Materials and Methods: Two loess-palaeosol sequences (Agh Band and Nowdeh sections were chosen in Golestan province, in northern Iran and step-wise profiles were prepared. Agh Band section is located in the western most part of the Northern Iranian loess plateau and has about 50 m thickness of loess deposits. Nowdeh loess-palaeosol sequence is located about 20 km southeast of Gonbad-e Kavus, in the vicinity of the Nowdeh River. Soil sampling was done in several field campaigns in spring 2012. More than 30cm of the surface deposits were removed in order to reach for undisturbed loess and palaeosols and one mixed sample was taken from each horizonA comparison of palaeosols with modern soils formed under known Holocene climatic conditions, which are derived from substrates with similar granulometric and mineralogical composition are suited for reconstructing past climate and environment. Hence, six modern soil profiles were prepared along the climosequnce and the vegetation cover changed from grassland in the dry area to dense shrub land and forest in the moist part of the ecological gradient. For reconstruction of palaeoenvironment (climate and vegetation some basic physico

  20. Late Quaternary strata and carbon burial records in the Yellow River delta, China

    Science.gov (United States)

    Zhao, Guangming; Ye, Siyuan; Li, Guangxue; Ding, Xigui; Yuan, Hongming

    2015-06-01

    Sediment carbon sequestration plays an essential role in mitigating atmospheric CO2 increases and the subsequently global greenhouse effect. To clarify the late Quaternary strata and carbon burial records in Yellow River delta (YRD), detailed analysis of benthic foraminifera, total carbon (TC), organic carbon (Corg), sedimentary characteristics and moisture contents of sediments, was performed on core ZK3, 30.3 m in length and obtained from YRD in 2007. Eight depositional units (designated U1-U8 in ascending order) were identified. A comprehensive analysis method of historical geography and sedimentary geology was used to determine the precise depositional ages of the modern Yellow River delta (MYRD), from which pre-MYRD ages were deduced. The results indicates that the maximum burial rates of TC, inorganic carbon (IC) and Corg occurred in the delta front (U5), and the minimum in the shallow sea (U3). Remarkable high sedimentation rates in the MYRD are responsible for burial efficiency of carbon, with an average rate of Corg burial reaching 2087±251 g (m2 yr)-1, and that of IC reaching 13741±808 g (m2 yr)-1, which are much higher than those of other regions with high contents of Corg. Therefore, YRD has a significant burial efficiency for carbon sequestration.

  1. Fault imprint in clay units: magnetic fabric, structural and mineralogical signature

    Science.gov (United States)

    Moreno, Eva; Homberg, Catherine; Schnyder, Johann; Person, Alain; du Peloux1, Arthur; Dick, Pierre

    2014-05-01

    Fault-induced deformations in clay units can be difficult to decipher because strain markers are not always visible at outcrop scale or using geophysical methods. Previous studies have indicated that the anisotropy of magnetic susceptibility (ASM) provides a powerful and rapid technique to investigate tectonic deformation in clay units even when they appear quite homogenous and undeformed at the outcrop scale (Lee et al. 1990, Mattei et al. 1997). We report here a study based on ASM, structural analysis and magnetic and clay mineralogy from two boreholes (TF1 and ASM1)drilled horizontally in the Experimental Station of Tournemire of the Institute for Radiological Protection and Nuclear Safety (IRSN) in Aveyron (France). The boreholes intersect a N-S trending strike-slip fault from west to east. The ASM study indicates the evolution of the magnetic fabric from the undeformed host rock to the fault core. Also, all the fractures cutting the studied interval of the core have been measured as well as the slip vectors which are generally well preserved. In the two boreholes, the undeformed sediments outside the fault zone are characterized by an oblate fabric, a sub-vertical minimum susceptibility axis (k3) perpendicular to the bedding plane and without magnetic lineation. Within the fault zone, a tilt in the bedding plane has been observed in two boreholes TF1 and ASM1. In addition, in the TF1 core, the fault area presents a tectonic fabric characterized by a triaxial AMS ellipsoid. Moreover, the magnetic lineation increases and k3 switches from a vertical to a sub-horizontal plane. This kind of fabric has not been observed in borehole ASM1. The structural analysis of the individual fractures making the fault zone indicates a complex tectonic history with different imprint in the two fault segments cut by the two boreholes. The large majority of fractures correspond to dextral strike-slip faults but normal and reverse movements were observed and are more or less

  2. Quaternary Fault and Fold Database of the United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Quaternary Fault and Fold Database contains the results of thousands of scientific assessments of faults and associated folds in the United States that...

  3. Quaternary alluvial stratigraphy and palaeoclimatic reconstruction at the Thar margin

    DEFF Research Database (Denmark)

    Jain, M.; Tandon, S.K.

    2003-01-01

    Quaternary alluvial record at the Thar desert margin has been examined using the exposed succession along Mahudi, Sabarmati river, Western India. Different alluvial facies, their associations and granulometry have been studied for palaeoenvironmental reconstruction. Clay mineral indices smectite/...

  4. Late Quaternary fine silt deposits of Jammu, NW Himalaya: Genesis and climatic significance

    Indian Academy of Sciences (India)

    Rajinder K Ganjoo; Vinod Kumar

    2012-02-01

    The fine silt deposits of Jammu (J & K State, India) stretch all along the Siwalik foothills from Jammu to the Potwar Plateau in Pakistan. The post-Siwalik deposits, first discussed by de Terra and Paterson (1939), are attributed to wind action. The deposits termed as ‘Potwar loessic silt’ comprising sandy silt are essentially of late Quaternary age (75–18 ka) and are re-looked herein from the point of view of genesis and climatic significance. The sorting, skewness and kurtosis parameters of fine silts of Jammu suggest fluvial environment of the deposits wherein the water budget fluctuated. The weak pedogenesis of fine silts at certain intervals corroborate to periods of less or no sedimentation. The bivariant plot studies further suggest fluvial environment of deposition for the fine silt at Jammu, with regular fluctuations in the budget of river water that was perhaps in consonance with oscillations in the climate of the region.

  5. ARE QUATERNARY AMMONIUM ANTIBACTERIALS SUITABLE FOR DENTAL COMPOSITE RESINS?

    Directory of Open Access Journals (Sweden)

    Iman MOHAMMADZADEH

    2016-06-01

    Full Text Available The objective of this study was to answer the following question: are quaternary ammonium antibacterials suitable for dental materials? Reviewing the literature on quaternary ammonium compounds evidenced that this type of compounds is soluble in water. Our own findings also showed that they are well soluble in water and that their application as dental composites requires to check their solubility level in water.

  6. Mapping the late Quaternary evolution of the lower Mississippi Valley

    Science.gov (United States)

    Haugerud, R. A.; Simon, K. M.; James, T. S.

    2013-12-01

    The lower Mississippi Valley (LMV) extends from Cape Girardeau to Natchez and from Little Rock to Memphis. Extensive Quaternary terraces within the LMV have been considered to reflect downstream changes in base level (global sea level) and (or) upstream changes in water and sediment input because of glaciation. We suggest that the first-order control on terrace development was glacial-isostatic adjustment (GIA). Observed variation in heights of Quaternary alluvial surfaces at Memphis is 50 m (Rittenour et al., 2007). GIA modeling by Clark et al. (1994) predicted vertical displacement of as much as 130 m at Memphis over the last 18,000 years. ICE-5G models predict smaller displacement and reinforce the viability of GIA as the primary cause of LMV aggradation and incision. Existing analyses of LMV terraces are built on geomorphic maps by Saucier and colleagues (1974, 1994; Autin et al., 1991) that were interpreted from aerial photographs and inch-to-the-mile contour maps. Geomorphic mapping from high-resolution DEMs is more accurate, more rapid, and more reproducible than mapping from aerial photography and intermediate-resolution contours. Working from lidar DEMs (1-5 m XY resolution) and the 10 m National Elevation Dataset (NED) DEM largely derived from 1:24,000 scale contours, Haugerud is mapping the geomorphology of the LMV at ~1:500,000 scale. Goals are to explore the GIA-terrace hypothesis and improve the geomorphic and stratigraphic context for studies of New Madrid seismicity. Mapping leads to several observations: 1. The Holocene floodplain of the Mississippi River onlaps older surfaces. The river appears to be filling a hole created by collapse of the Laurentide forebulge. Continued filling of this accommodation space will, barring human intervention, enable the river to abandon its course through Thebes Gap in favor of a lower-elevation route through Oran Gap. 2. Within Holocene meander belts, younger levee crests are higher than older levee crests. The

  7. Known and suggested quaternary faulting in the midcontinent United States

    Science.gov (United States)

    Wheeler, R.L.; Crone, A.J.

    2001-01-01

    The midcontinent United States between the Appalachian and Rocky Mountains contains 40 known faults or other potentially tectonic features for which published geologic information shows or suggests Quaternary tectonic faulting. We report results of a systematic evaluation of published and other publicly available geologic evidence of Quaternary faulting. These results benefit seismic-hazard assessments by (1) providing some constraints on the recurrence intervals and magnitudes of large, prehistoric earthquakes, and (2) identifying features that warrant additional study. For some features, suggested Quaternary tectonic faulting has been disproved, whereas, for others, the suggested faulting remains questionable. Of the 40 features, nine have clear geologic evidence of Quaternary tectonic faulting associated with prehistoric earthquakes, and another six features have evidence of nontectonic origins. An additional 12 faults, uplifts, or historical seismic zones lack reported paleoseismological evidence of large. Quaternary earthquakes. The remaining 13 features require further paleoseismological study to determine if they have had Quaternary earthquakes that were larger than any known from local historical records; seven of these 13 features are in or near urbanized areas where their study could affect urban hazard estimates. These seven are: (1) the belt of normal faults that rings the Gulf of Mexico from Florida to Texas. (2) the Northeast Ohio seismic zone, (3) the Valmont and (4) Goodpasture faults of Colorado. (5) the Champlain lowlands normal faults of New York State and Vermont, and (6) the Lexington and (7) Kentucky River fault systems of eastern Kentucky. Published by Elsevier Science B.V.

  8. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  9. Mechanisms of fluoride release in sediments of Argentina's central region.

    Science.gov (United States)

    Borgnino, L; Garcia, M G; Bia, G; Stupar, Y V; Le Coustumer, Ph; Depetris, P J

    2013-01-15

    We analyze the sources and mechanisms that control the release of fluoride from sediments collected from two types of aquatic reservoirs in the central region of Argentina: 1) mountainous rivers draining crystalline rocks from the Sierras Pampeanas ranges, and 2) shallow aquifers in loessic sediments. The assessment was performed on the basis of experimental work and the study of chemical and mineralogical characteristics of sediments in contact with F-rich waters of the studied region. The chemical and mineralogical compositions of sediments were analyzed by ICP/OES, DRX, and SEM-EDS. Batch experiments were conducted to evaluate the kinetics of fluoride release under variable pH and ionic composition of the solution. The enhanced release of fluoride at more acidic pH, the inhibition of release in Ca-rich solutions and the positive significant linear trends between Ca(2+) and fluoride concentrations suggest that the dissolution of a Ca/F-bearing phase (like fluorapatite) strongly controls the dynamics of fluoride in the early stages of water-sediment interaction, particularly under acidic conditions. Calculations revealed that the dissolution of an amount of FAp equivalent to that estimated in the studied sediments may widely account for the values measured in the leaching experiments at pH6, whatever the dominant cation in the solution. Under such conditions, dissolution of FAp (present as coatings onto glass surfaces or as detritic grains) is likely the major primary source of fluorine in the studied sediments. Contribution from biotite may be also considered as a source in fluvial sediments. When adequate surfaces are present the released anions may partially be scavenged from the solution by adsorption at acidic pH. Increasing alkalinity in the aquatic reservoirs may then release the adsorbed fluoride through desorption or through competition with other anionic species. Comparing both mechanisms, dissolution predominates at lower pH while desorption is the main

  10. The Gediz River fluvial archive: A benchmark for Quaternary research in Western Anatolia

    Science.gov (United States)

    Maddy, D.; Veldkamp, A.; Demir, T.; van Gorp, W.; Wijbrans, J. R.; van Hinsbergen, D. J. J.; Dekkers, M. J.; Schreve, D.; Schoorl, J. M.; Scaife, R.; Stemerdink, C.; van der Schriek, T.; Bridgland, D. R.; Aytaç, A. S.

    2017-06-01

    The Gediz River, one of the principal rivers of Western Anatolia, has an extensive Pleistocene fluvial archive that potentially offers a unique window into fluvial system behaviour on the western margins of Asia during the Quaternary. In this paper we review our work on the Quaternary Gediz River Project (2001-2010) and present new data which leads to a revised stratigraphical model for the Early Pleistocene development of this fluvial system. In previous work we confirmed the preservation of eleven buried Early Pleistocene fluvial terraces of the Gediz River (designated GT11, the oldest and highest, to GT1, the youngest and lowest) which lie beneath the basalt-covered plateaux of the Kula Volcanic Province. Deciphering the information locked in this fluvial archive requires the construction of a robust geochronology. Fortunately, the Gediz archive provides ample opportunity for age-constraint based upon age estimates derived from basaltic lava flows that repeatedly entered the palaeo-Gediz valley floors. In this paper we present, for the first time, our complete dataset of 40Ar/39Ar age estimates and associated palaeomagnetic measurements. These data, which can be directly related to the underlying fluvial deposits, provide age constraints critical to our understanding of this sequence. The new chronology establishes the onset of Quaternary volcanism at ∼1320ka (MIS42). This volcanism, which is associated with GT6, confirms a pre-MIS42 age for terraces GT11-GT7. Evidence from the colluvial sequences directly overlying these early terraces suggests that they formed in response to hydrological and sediment budget changes forced by climate-driven vegetation change. The cyclic formation of terraces and their timing suggests they represent the obliquity-driven climate changes of the Early Pleistocene. By way of contrast the GT5-GT1 terrace sequence, constrained by a lava flow with an age estimate of ∼1247ka, span the time-interval MIS42 - MIS38 and therefore do not

  11. Grainsize and Mineralogy Data of Sediments Samples Collected at Crocker Reef, Florida, 2013-2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Understanding the processes that govern whether a coral reef is accreting (growing) or dissolving are fundamental to questions of reef health and resiliency. A total...

  12. Clay Mineralogy of Shallow Core Sediments of Lake Acigöl, Denizli, Turkey

    Science.gov (United States)

    Budakoglu, Murat; Karaman, Muhittin; Geredeli, Serpil; Unal, Hatice; Abdelnasser, Amr; Kiran Yildirim, Demet

    2014-05-01

    Lake Acıgöl is a hypersaline and active industrial salt production lake located in Denizli, Turkey. Lake Acıgöl has been investigated to elucidate the distribution clay minerals under the saline conditions of the lake and carbonate and ophiolitic rocks controlled lake basin. The lake is very shallow and generally characterized by an un-stratified and whole oxygenated water table. Determination clay minerals in the bulk samples via XRD method was not possible due to the their small amount. Therefore, the sequential clay enrichment procedure applied to the bulk samples such as sample dispersion, removal of soluble salts and ions, and particle-size fractionation. The XRD analyses of normal, glycolated and heat-treated shallow core samples show that the dominant clay minerals in the samples to be illite, including the swelling montmorillonite and kaolinite minerals are encountered less frequently. Glauberite, Blodite, Dansite and Nickelblodite have been also identified as soda minerals by XRD studies.

  13. Mineralogical and geochemical characterization of hydrocarbon seep sediments from the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Canet, Carles; Prol-Ledesma, Rosa Maria; Mortera-Gutierrez, Carlos; Linares, Carlos [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico); Escobar-Briones, Elva [Instituto de Ciencias del Mar y Limnologia, Unidad Academica Sistemas Oceanograficos y Costeros, A. P. 70-305 Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico); Lozano-Santa Cruz, Rufino; Cienfuegos, Edith; Morales-Puente, Pedro [Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico)

    2006-06-15

    A common characteristic of the Gulf of Mexico (GOM) seafloor, hydrocarbon seepage produces asphalt volcanism, brine pools, gas hydrates and authigenic carbonates. We studied authigenic carbonates from two areas: Green Canyon (Louisiana slope, 1000mbsl) and the Chapopote diapir (abyssal plain, southwestern GOM, 2900mbsl). Carbonates consist of oily, matrix-supported limestones with variable porosity and a fine-grained matrix of calcite. They occur in Green Canyon as both concretions formed below the seafloor and as slabs of seabed pavements. In each case, the carbonates are mudstones with a mud matrix consisting of high-Mg calcite, disseminated pyrite and detrital quartz. The carbonate slabs have vug microporosity and contain barite that occurs as vug lining. The precipitation of barite results from a reaction between barium-rich and sulfate-free seep fluids and downwards-diffusing seawater. The carbonates in Chapopote occur in relation to tar flows and form crusts of wackestones with bivalve shells. The matrix is composed by low-Mg calcite with disseminated pyrite and detrital quartz. The carbonate mud shows depletion in {sup 13}C, with {delta}{sup 13}C between -36.9%% and -23.0%%. Carbonates precipitate as a consequence of anaerobic methane oxidation coupled with seawater sulfate reduction. {delta}{sup 18}O values (3.4-4.4%%) suggest precipitation at temperatures between 5 and 9{sup o}C. (author)

  14. Pliocene-Quaternary contourites along the northern Gulf of Cadiz margin: sedimentary stacking pattern and regional distribution

    Science.gov (United States)

    Llave, Estefanía; Matias, Hugo; Hernández-Molina, F. Javier; Ercilla, Gemma; Stow, Dorrik A. V.; Medialdea, Teresa

    2011-12-01

    This study reports novel findings on the Pliocene-Quaternary history of the northern Gulf of Cadiz margin and the spatiotemporal evolution of the associated contourite depositional system. Four major seismic units (P1, P2, QI and QII) were identified in the Pliocene-Quaternary sedimentary record based on multichannel seismic profiles. These are bounded by five major discontinuities which, from older to younger, are the M (Messinian), LPR (lower Pliocene revolution), BQD (base Quaternary discontinuity), MPR (mid-Pleistocene revolution) and the actual seafloor. Unit P1 represents pre-contourite hemipelagic/pelagic deposition along the northern Gulf of Cadiz margin. Unit P2 reflects a significant change in margin sedimentation when contourite deposition started after the Early Pliocene. Mounded elongated and separated drifts were generated during unit QI deposition, accompanied by a general upslope progradation of drifts and the migration of main depocentres towards the north and northwest during both the Pliocene and Quaternary. This progradation became particularly marked during QII deposition after the mid-Pleistocene (MPR). Based on the spatial distribution of the main contourite depocentres and their thickness, three structural zones have been identified: (1) an eastern zone, where NE-SW diapiric ridges have controlled the development of two internal sedimentary basins; (2) a central zone, which shows important direct control by the Guadalquivir Bank in the south and an E-W Miocene palaeorelief structure in the north, both of which have significantly conditioned the basin-infill geometry; and (3) a western zone, affected in the north by the Miocene palaeorelief which favours deposition in the southern part of the basin. Pliocene tectonic activity has been an important factor in controlling slope morphology and, hence, influencing Mediterranean Outflow Water pathways. Since the mid-Pleistocene (MPR), the sedimentary stacking pattern of contourite drifts has been

  15. A Quaternary Fault Database for Central Asia

    Directory of Open Access Journals (Sweden)

    S. Mohadjer

    2015-09-01

    Full Text Available Earthquakes represent the highest risk in terms of potential loss of lives and economic damage for Central Asian countries. Knowledge of fault location and behavior is essential in calculating and mapping seismic hazard. Previous efforts in compiling fault information for Central Asia have generated a large amount of data that are published in limited-access journals with no digital maps publicly available, or are limited in their description of important fault parameters such as slip rates. This study builds on previous work by improving access to fault information through a web-based interactive map and an online database with search capabilities that allow users to organize data by different fields. The data presented in this compilation include fault location, its geographic, seismic and structural characteristics, short descriptions, narrative comments and references to peer-reviewed publications. The interactive map displays 1196 fault segments and 34 000 earthquake locations on a shaded-relief map. The online database contains attributes for 122 faults mentioned in the literature, with Quaternary and geodetic slip rates reported for 38 and 26 faults respectively, and earthquake history reported for 39 faults. This work has implications for seismic hazard studies in Central Asia as it summarizes important fault parameters, and can reduce earthquake risk by enhancing public access to information. It also allows scientists and hazard assessment teams to identify structures and regions where data gaps exist and future investigations are needed.

  16. Quaternary stratigraphy and palaeogeography of Poland

    Science.gov (United States)

    Marks, Leszek; Dzierżek, Jan; Janiszewski, Robert; Kaczorowski, Jarosław; Lindner, Leszek; Majecka, Aleksandra; Makos, Michał; Szymanek, Marcin; Tołoczko-Pasek, Anna; Woronko, Barbara

    2016-09-01

    Though the stratigraphical and palaeogeographical framework of the Quaternary in Poland is still to be completed, several crucial points have been confirmed recently. The preglacial series, accepted for years as belonging to the Lower Pleistocene, is undoubtedly of Early Pliocene age, with a huge hiatus above almost until the uppermost Lower Pleistocene. The earliest glaciation in Poland (Nidanian) occurred at about 900 ka BP when the ice sheet reached the mid-southern part of the country. The following Podlasian Interglacial embraced the Brunhes/Matuyama boundary in the middle, in a similar fashion to the corresponding Cromerian Complex in Western Europe. The late Early and early Middle Pleistocene interglacials in Poland comprised 2-3 optima each, whereas every one of the younger interglacials was characterised by a single optimum only. The Late Vistulian ice sheet was most extensive in the western part of Poland (Leszno Phase) whereas the younger Poznań Phase was more extensive in the central and eastern part of the country. This was due to the varied distance from the glaciation center in Scandinavia, making the ice sheet margin reach a terminal position in different times. Palaeoclimatological research in the Tatra Mountains has provided new evidence for the atmospheric circulation over Europe. During cold phases of the Pleistocene in Poland a continental climate extended further westwards, quite the opposite that occurring during warmer intervals.

  17. A Quaternary Fault Database for Central Asia

    Science.gov (United States)

    Mohadjer, S.; Ehlers, T. A.; Bendick, R.; Stübner, K.; Strube, T.

    2015-09-01

    Earthquakes represent the highest risk in terms of potential loss of lives and economic damage for Central Asian countries. Knowledge of fault location and behavior is essential in calculating and mapping seismic hazard. Previous efforts in compiling fault information for Central Asia have generated a large amount of data that are published in limited-access journals with no digital maps publicly available, or are limited in their description of important fault parameters such as slip rates. This study builds on previous work by improving access to fault information through a web-based interactive map and an online database with search capabilities that allow users to organize data by different fields. The data presented in this compilation include fault location, its geographic, seismic and structural characteristics, short descriptions, narrative comments and references to peer-reviewed publications. The interactive map displays 1196 fault segments and 34 000 earthquake locations on a shaded-relief map. The online database contains attributes for 122 faults mentioned in the literature, with Quaternary and geodetic slip rates reported for 38 and 26 faults respectively, and earthquake history reported for 39 faults. This work has implications for seismic hazard studies in Central Asia as it summarizes important fault parameters, and can reduce earthquake risk by enhancing public access to information. It also allows scientists and hazard assessment teams to identify structures and regions where data gaps exist and future investigations are needed.

  18. A Quaternary fault database for central Asia

    Science.gov (United States)

    Mohadjer, Solmaz; Ehlers, Todd Alan; Bendick, Rebecca; Stübner, Konstanze; Strube, Timo

    2016-02-01

    Earthquakes represent the highest risk in terms of potential loss of lives and economic damage for central Asian countries. Knowledge of fault location and behavior is essential in calculating and mapping seismic hazard. Previous efforts in compiling fault information for central Asia have generated a large amount of data that are published in limited-access journals with no digital maps publicly available, or are limited in their description of important fault parameters such as slip rates. This study builds on previous work by improving access to fault information through a web-based interactive map and an online database with search capabilities that allow users to organize data by different fields. The data presented in this compilation include fault location, its geographic, seismic, and structural characteristics, short descriptions, narrative comments, and references to peer-reviewed publications. The interactive map displays 1196 fault traces and 34 000 earthquake locations on a shaded-relief map. The online database contains attributes for 123 faults mentioned in the literature, with Quaternary and geodetic slip rates reported for 38 and 26 faults respectively, and earthquake history reported for 39 faults. All data are accessible for viewing and download via http://www.geo.uni-tuebingen.de/faults/. This work has implications for seismic hazard studies in central Asia as it summarizes important fault parameters, and can reduce earthquake risk by enhancing public access to information. It also allows scientists and hazard assessment teams to identify structures and regions where data gaps exist and future investigations are needed.

  19. Late Quaternary history of contourite drifts and variations in Labrador Current flow, Flemish Pass, offshore eastern Canada

    Science.gov (United States)

    Marshall, Nicole R.; Piper, David J. W.; Saint-Ange, Francky; Campbell, D. Calvin

    2014-10-01

    Contourite drifts of alternating sand and mud, shaped by the Labrador Current, formed during the late Quaternary in Flemish Pass seaward of the Grand Banks of Newfoundland, Canada. The drifts preserve a record of Labrador Current flow variations through the last glacial maximum. A high-resolution seismic profile and a transect of four cores were collected across Beothuk drift on the southeast side of Flemish Pass. Downcore and lateral trends in grain size and sedimentation rate provide evidence that, between 16 and 13 ka, sediment was partitioned across Beothuk drift and the adjacent Flemish Pass floor by a strong current flow but, from 29 to 16 ka, sedimentation was more of a blanketing style, represented by draped reflections interpreted as being due to a weaker current. The data poorly resolve the low sedimentation rates since 13 ka, but the modern Labrador Current in Flemish Pass is the strongest it has been in at least the past 29 ka. Pre-29 ka current flow is interpreted based on reflection architecture in seismic profiles. A prominent drift on the southwestern side of Flemish Pass formed above a mid-Miocene erosion surface, but was buried by a mass-transport deposit after the penultimate glacial maximum and after drift deposition switched to eastern Flemish Pass. These findings illustrate the temporal complexity of drift sedimentation and provide the first detailed proxy for Labrador Current flow since the last glacial maximum.

  20. Quaternary Sea-ice history in the Arctic Ocean based on a new Ostracode sea-ice proxy

    Science.gov (United States)

    Cronin, T. M.; Gemery, L.; Briggs, W.M.; Jakobsson, M.; Polyak, L.; Brouwers, E.M.

    2010-01-01

    Paleo-sea-ice history in the Arctic Ocean was reconstructed using the sea-ice dwelling ostracode Acetabulastoma arcticum from late Quaternary sediments from the Mendeleyev, Lomonosov, and Gakkel Ridges, the Morris Jesup Rise and the Yermak Plateau. Results suggest intermittently high levels of perennial sea ice in the central Arctic Ocean during Marine Isotope Stage (MIS) 3 (25-45 ka), minimal sea ice during the last deglacial (16-11 ka) and early Holocene thermal maximum (11-5 ka) and increasing sea ice during the mid-to-late Holocene (5-0 ka). Sediment core records from the Iceland and Rockall Plateaus show that perennial sea ice existed in these regions only during glacial intervals MIS 2, 4, and 6. These results show that sea ice exhibits complex temporal and spatial variability during different climatic regimes and that the development of modern perennial sea ice may be a relatively recent phenomenon. ?? 2010.

  1. The characteristics of soil and water loss in Pinus Massoniana forest in Quaternary red soil area of south China

    Science.gov (United States)

    Song, Yuejun; Huang, Yanhe; Jie, Yang

    2017-08-01

    The soil and water loss in Pinus massoniana forests is an urgent environmental problem in the red soil region of southern China.Using the method of field monitoring, by analogy and statistical analysis, The characteristics of soil and water loss of Pinus massoniana forests in Quaternary red soil region under 30 rainfall were analyzed,the results show that the relationship models of rainfall,runoff and sediment of pure Pinus massoniana plot were slightly different from the naked control plot,were all the univariate quadratic linear regression models.the contribution of runoff and sediment in different rain types were different, and the water and soil loss in Pinus massoniana forest was most prominent under moderate rain.The merging effect of sparse Pinus massoniana forest on raindrop, aggravated the degree of soil and water loss to some extent.

  2. Late Quaternary Faulting along the San Juan de los Planes Fault Zone, Baja California Sur, Mexico

    Science.gov (United States)

    Busch, M. M.; Coyan, J. A.; Arrowsmith, J.; Maloney, S. J.; Gutierrez, G.; Umhoefer, P. J.

    2007-12-01

    Los Planes highway, the fault steps to the right 2km with no overlap. The fault is inactive until ~3km south of the Los Planes highway where scarp heights in the Quaternary sediments rise to ~3-11m for ~11km with an average trend of 160°, implying increasing slip rate. The fault then steps left 2km with no overlap, trending 145°. Scarp heights range from 3-6m in the step. The southernmost 9km of the fault zone, trending 200°, is marked by discontinuous scarps and embayed bedrock, reflecting diminished fault activity. The footwall landscape in this area is characterized by a broad, gently-sloping, low-relief pediment surface with thin Quaternary cover, disrupted by inselberg-like hills. The young scarp-forming fault appears to have reactivated older faults to rupture this pediment, reflecting the episodic nature of slip along this fault zone. Preliminary OSL ages of the youngest faulted deposit imply a Late Pleistocene-Holocene slip rate of 0.1-1mm/yr. The SJPFZ is thus characterized by reactivation of pre-existing faults to rupture a pre-existing low relief erosional landscape. Whereas the entire region might have experienced the quiescent period that allowed for development of the low- relief, stable surface along the SJPFZ, we speculate that while the SJPFZ was dormant, other faults within the gulf-margin system were actively accommodating strain.

  3. Assessing Biological and Stratigraphic Determinants of Fossil Abundance: A Case Example from the Late Quaternary of Po Plain, Italy

    Science.gov (United States)

    Kowalewski, Michal; Azzarone, Michele; Kusnerik, Kristopher; Dexter, Troy; Wittmer, Jacalyn; Scarponi, Daniele

    2017-04-01

    Absolute fossil abundance [AFA] can be defined as a relative concentration of identifiable fossils per unit of sediment. AFA, or "sediment shelliness", is controlled by the interplay between the rate of input of skeletal remains (biological productivity), pace of shell destruction (taphonomy), rate of sedimentation, and sediment compaction. Understanding the relative importance of those drivers can augment both stratigraphic and biological interpretations of the fossil record. Using 336 samples from a network of late Quaternary cores drilled in Po Plain (Italy), we examined the importance of those factors in controlling the stratigraphic distribution of fossils. All samples were vertically and volumetrically equivalent, each representing a 10 cm long interval of a core with a diameter of 7 cm ( 0.375 dm3 sediment per sample). Sample-level estimates of AFA (1) varied over 4 orders of magnitudes (from 4000 specimens per dm3) were characterized by exceedingly low evenness reflecting dominance by one super-abundant species (Berger-Parker index > 0.8 in all cases). These super-abundant species were limited to small r-selective mollusks capable of an explosive population growth: the marine corbulid bivalve Lentidium mediterraneum and the brackish hyrdobiid gastropod Ecrobia ventrosa. Moreover, despite high mollusk diversity (534 species total), >80% of samples are dominated by one of the five mollusk species, which all represent small, r-selective, deposit and suspension feeders. Trends in absolute fossil abundance within late Quaternary deposits of the Po Plain appear to have been driven primarily by biological productivity of opportunistic shelly species from lowest trophic levels. In the studied system, biodiversity and shelliness of samples is unlikely to reflect stratigraphic or taphonomic overprints, but rather records the ecological importance of r-selective species that dominated the investigated area throughout the late Quaternary. The joint consideration of

  4. Compositional Data for Bengal Delta Sediment Collected from a Borehole at Rajoir, Bangladesh

    Science.gov (United States)

    Breit, George N.; Yount, James C.; Uddin, Md. Nehal; Muneem, Ad. Atual; Lowers, Heather; Berry, Cyrus J.; Whitney, John W.

    2007-01-01

    Processes active within sediment of the Bengal basin have attracted world concern because of the locally high content of arsenic dissolved in ground water drawn from that sediment. Sediment samples were collected from a borehole in the town of Rajoir, Rajoir upazila, Madaripur district, Bangladesh, to investigate the processes contributing to arsenic contamination. The samples were mineralogically and chemically analyzed to determine compositional variations related to the arsenic content of the sediment. Mineralogy of the sediment was determined using powder X-ray diffraction. Bulk chemical composition was measured by Combustion; Inductively Coupled Plasma Atomic Emission Spectroscopy; Energy Dispersive X-ray Fluorescence; and Hydride Generation Atomic Absorption Spectrophotometry. Sediment was treated with 0.5 N HCl and resulting solutions were analyzed, primarily to evaluate the abundance and oxidation state of acid-soluble iron. Acid-volatile sulfide, acid-soluble sulfate, and reducible sulfide were also measured on a few samples. Sediment sampled at Rajoir is typically unlithified, gray, micaceous, feldspathic arenaceous sand with a few silt and clay layers. Arsenic content of the sediment ranges from 0.6 to 21 ppm with a median of 1.2 ppm.

  5. Late Quaternary Advance and Retreat of an East Antarctic Ice Shelf System: Insights from Sedimentary Beryllium-10 Concentrations

    Science.gov (United States)

    Guitard, M. E.; Shevenell, A.; Domack, E. W.; Rosenheim, B. E.; Yokoyama, Y.

    2014-12-01

    Observed retreat of Antarctica's marine-based glaciers and the presence of warm (~2°C) modified Circumpolar Deep Water on Antarctica's continental shelves imply ocean temperatures may influence Antarctic cryosphere stability. A paucity of information regarding Late Quaternary East Antarctic cryosphere-ocean interactions makes assessing the variability, timing, and style of deglacial retreat difficult. Marine sediments from Prydz Bay, East Antarctica contain hemipelagic siliceous mud and ooze units (SMO) alternating with glacial marine sediments. The record suggests Late Quaternary variability of local outlet glacier systems, including the Lambert Glacier/Amery Ice Shelf system that drains 15% of the East Antarctic Ice Sheet. We present a refined radiocarbon chronology and beryllium-10 (10Be) record of Late Quaternary depositional history in Prydz Channel, seaward of the Amery Ice Shelf system, which provides insight into the timing and variability of this important outlet glacier system. We focus on three piston cores (NBP01-01, JPC 34, 35, 36; 750 m water depth) that contain alternating SMO and granulated units uninterrupted by glacial till; the record preserves a succession of glacial marine deposits that pre-date the Last Glacial Maximum. We utilize the ramped pyrolysis preparatory method to improve the bulk organic carbon 14C-based chronology for Prydz Channel. To determine if the SMO intervals reflect open water conditions or sub-ice shelf advection, we measured sedimentary 10Be concentrations. Because ice cover affects 10Be pathways through the water column, sedimentary concentrations should provide information on past depositional environments in Prydz Channel. In Prydz Channel sediments, 10Be concentrations are generally higher in SMO units and lower in glacial units, suggesting Late Quaternary fluctuations in the Amery Ice Shelf. Improved chronologic constraints indicate that these fluctuations occurred on millennial timescales during the Last Glacial

  6. On the relationship between luminescence excitation spectra and feldspar mineralogy

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

    1996-01-01

    Feldspar minerals can be used as naturally occurring radiation dosemeters, with dose assessment commonly using luminescence techniques. Since many feldspars contain radioactive K-40, knowledge of the mineralogy of the luminescent samples being measured is of high importance. Most feldspars contain...... more than trace amounts of highly luminescent Fe3+ impurities, and this article examines the relationship between features of the luminescence excitation spectrum of this ion with sample mineralogy. It is demonstrated that there is a near linear correspondence between the plagioclase feldspar...... groups. The results are compared with properties of the excitation spectra dose-dependent optically stimulated luminescence (OSL) in order to compare the chemical environment of the OSL donor defect, and the isolated Fe3+ centres....

  7. Polishing surgical metal pieces, granulomatosis and mineralogical analysis.

    Science.gov (United States)

    Catinon, Mickaël; Chemarin, C; Roux, E; Cavalin, C; Rosental, P-A; Thivolet-Bejui, F; Vincent, M

    2016-08-01

    This report describes the case of a 44-year-old man with pulmonary nodules whose histological analysis initially suggested tuberculosis. The Mycobacterium tuberculosis (MT) culture was negative and a questionnaire revealed a professional activity of brushing and polishing surgical instruments without any protection for 7 years.  A mineralogical analysis by optical and electron microscopy was performed on both a healthy lung tissue biopsy and a lung nodule in a paraffin block. Electron microscopy analysis revealed the presence of metal particles (iron oxide, titanium oxide, aluminum oxide and steel) in both samples. This study suggests that mineralogical analysis combined with a questionnaire on dust exposure could help redirect the diagnosis of a dust-related disease.

  8. Major, trace and REE geochemistry of recent sediments from lower Catumbela River (Angola)

    Science.gov (United States)

    Vinha, Manuela; Silva, M. G.; Cabral Pinto, Marina M. S.; Carvalho, Paula Cristina S.

    2016-03-01

    The mineralogy, texture, major, trace and rare earth elements, from recent sediment samples collected in the lower Catumbela River, were analysed in this study to characterize and discuss the factors controlling its geochemistry and provide data that can be used as tracers of Catumbela River inputs to the Angolan continental shelf. The sediments are mainly sands and silty-sands, but sandy-silt also occurs and the mineralogy is composed of quartz, feldspar, phyllosilicates, magnetite, ilmenite and also carbonates when the river crosses limestones and marls in the downstream sector. The hydraulic sorting originates magnetite-ilmenite and REE-enriched minerals placers. The mineralogy of the sediments is controlled by the source rocks and the degree of chemical weathering is lower than erosion. The texture is mainly controlled by location. There is enrichment in all the analysed trace elements in the fine grained, clay minerals and Fe-oxy-hydroxides rich sediments, compared to the coarse grained and quartz plus feldspar rich ones. The coarse grained sediments (without the placers) are impoverished in ΣREE when compared with UCC and NASC compositions, while the fine grained sediments have ΣREE contents similar to UCC and NASC. The placers have ΣREE contents up to 959.59 mg/kg. The source composition is the dominant factor controlling the REE geochemistry of the analysed sediments as there is no difference in the (La/Yb)N, (La/Sm)N and (Gd/Yb)N ratios in coarse and fine grained sediments. The sorting of magnetite, ilmenite, zircon, throrite, thorianite, rutile and titanite explain the HREE/LREE enriched patterns of the coarse grained sediments.

  9. Mineralogy and geochemistry of the main glauconite bed in the Middle Eocene of Texas: paleoenvironmental implications for the verdine facies.

    Directory of Open Access Journals (Sweden)

    Sherie C Harding

    Full Text Available The Main Glauconite Bed (MGB is a pelleted greensand located at Stone City Bluff on the south bank of the Brazos River in Burleson County, Texas. It was deposited during the Middle Eocene regional transgression on the Texas Gulf Coastal Plain. Stratigraphically it lies in the upper Stone City Member, Crockett Formation, Claiborne Group. Its mineralogy and geochemistry were examined in detail, and verdine facies minerals, predominantly odinite, were identified. Few glauconitic minerals were found in the green pelleted sediments of the MGB. Without detailed mineralogical work, glaucony facies minerals and verdine facies minerals are easily mistaken for one another. Their distinction has value in assessing paleoenvironments. In this study, several analytical techniques were employed to assess the mineralogy. X-ray diffraction of oriented and un-oriented clay samples indicated a clay mixture dominated by 7 and 14Å diffraction peaks. Unit cell calculations from XRD data for MGB pellets match the odinite-1M data base. Electron microprobe analyses (EMPA from the average of 31 data points from clay pellets accompanied with Mössbauer analyses were used to calculate the structural formula which is that of odinite: Fe(3+ 0.89 Mg0.45 Al0.67 Fe(2+ 0.30 Ti0.01 Mn0.01 Σ = 2.33 (Si1.77 Al0.23 O5.00 (OH4.00. QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy data provided mineral maps of quantitative proportions of the constituent clays. The verdine facies is a clay mineral facies associated with shallow marine shelf and lagoonal environments at tropical latitudes with iron influx from nearby runoff. Its depositional environment is well documented in modern nearshore locations. Recognition of verdine facies clays as the dominant constituent of the MGB clay pellets, rather than glaucony facies clays, allows for a more precise assessment of paleoenvironmental conditions.

  10. Mineralogy and geochemistry of the main glauconite bed in the Middle Eocene of Texas: paleoenvironmental implications for the verdine facies.

    Science.gov (United States)

    Harding, Sherie C; Nash, Barbara P; Petersen, Erich U; Ekdale, A A; Bradbury, Christopher D; Dyar, M Darby

    2014-01-01

    The Main Glauconite Bed (MGB) is a pelleted greensand located at Stone City Bluff on the south bank of the Brazos River in Burleson County, Texas. It was deposited during the Middle Eocene regional transgression on the Texas Gulf Coastal Plain. Stratigraphically it lies in the upper Stone City Member, Crockett Formation, Claiborne Group. Its mineralogy and geochemistry were examined in detail, and verdine facies minerals, predominantly odinite, were identified. Few glauconitic minerals were found in the green pelleted sediments of the MGB. Without detailed mineralogical work, glaucony facies minerals and verdine facies minerals are easily mistaken for one another. Their distinction has value in assessing paleoenvironments. In this study, several analytical techniques were employed to assess the mineralogy. X-ray diffraction of oriented and un-oriented clay samples indicated a clay mixture dominated by 7 and 14Å diffraction peaks. Unit cell calculations from XRD data for MGB pellets match the odinite-1M data base. Electron microprobe analyses (EMPA) from the average of 31 data points from clay pellets accompanied with Mössbauer analyses were used to calculate the structural formula which is that of odinite: Fe(3+) 0.89 Mg0.45 Al0.67 Fe(2+) 0.30 Ti0.01 Mn0.01) Σ = 2.33 (Si1.77 Al0.23) O5.00 (OH)4.00. QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) data provided mineral maps of quantitative proportions of the constituent clays. The verdine facies is a clay mineral facies associated with shallow marine shelf and lagoonal environments at tropical latitudes with iron influx from nearby runoff. Its depositional environment is well documented in modern nearshore locations. Recognition of verdine facies clays as the dominant constituent of the MGB clay pellets, rather than glaucony facies clays, allows for a more precise assessment of paleoenvironmental conditions.

  11. Mineralogy and Geochemistry of the Main Glauconite Bed in the Middle Eocene of Texas: Paleoenvironmental Implications for the Verdine Facies

    Science.gov (United States)

    Harding, Sherie C.; Nash, Barbara P.; Petersen, Erich U.; Ekdale, A. A.; Bradbury, Christopher D.; Dyar, M. Darby

    2014-01-01

    The Main Glauconite Bed (MGB) is a pelleted greensand located at Stone City Bluff on the south bank of the Brazos River in Burleson County, Texas. It was deposited during the Middle Eocene regional transgression on the Texas Gulf Coastal Plain. Stratigraphically it lies in the upper Stone City Member, Crockett Formation, Claiborne Group. Its mineralogy and geochemistry were examined in detail, and verdine facies minerals, predominantly odinite, were identified. Few glauconitic minerals were found in the green pelleted sediments of the MGB. Without detailed mineralogical work, glaucony facies minerals and verdine facies minerals are easily mistaken for one another. Their distinction has value in assessing paleoenvironments. In this study, several analytical techniques were employed to assess the mineralogy. X-ray diffraction of oriented and un-oriented clay samples indicated a clay mixture dominated by 7 and 14Å diffraction peaks. Unit cell calculations from XRD data for MGB pellets match the odinite-1M data base. Electron microprobe analyses (EMPA) from the average of 31 data points from clay pellets accompanied with Mössbauer analyses were used to calculate the structural formula which is that of odinite: Fe3+0.89 Mg0.45 Al0.67 Fe2+0.30 Ti0.01 Mn0.01) Σ = 2.33 (Si1.77 Al0.23) O5.00 (OH)4.00. QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) data provided mineral maps of quantitative proportions of the constituent clays. The verdine facies is a clay mineral facies associated with shallow marine shelf and lagoonal environments at tropical latitudes with iron influx from nearby runoff. Its depositional environment is well documented in modern nearshore locations. Recognition of verdine facies clays as the dominant constituent of the MGB clay pellets, rather than glaucony facies clays, allows for a more precise assessment of paleoenvironmental conditions. PMID:24503875

  12. Mineralogy and cooling history of magnesian lunar granulite 67415

    Science.gov (United States)

    Takeda, Hiroshi; Miyamoto, Masamichi

    1993-01-01

    Apollo granulite 67415 was investigated by mineralogical techniques to gain better understanding of cooling histories of lunar granulities. Cooling rates were estimated from chemical zoning of olivines in magnesian granulitic clasts by computer simulation of diffusion processes. The cooling rate of 10 deg C/yr obtained is compatible with a model of the granulite formation, in which the impact deposit was cooled from high temperature or annealed, at the depth of about 25 m beneath the surface.

  13. Fracture mineralogy of the Forsmark site. SDM-Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Sandstroem, Bjoern (Dept. of Earth Sciences, Univ. of Goeteborg (Sweden)); Tullborg, Eva-Lena (Terralogica AB, Graabo (Sweden)); Smellie, John (Conterra AB, Luleaa (Sweden)); MacKenzie, Angus B. (SUERC, Scottish Enterprise Technology Park, East Kilbride (United Kingdom)); Suksi, Juhani (Dept. of Chemistry, Univ. of Helsinki, Helsinki (Finland))

    2008-08-15

    Detailed investigations of the fracture mineralogy and altered wall rock have been carried out as part of the site characterisation programme between 2003 and 2007 at Forsmark. The results have been published in a number of P-reports and in contributions to scientific journals. This report summarises and evaluates the data obtained during the detailed fracture mineralogical studies. The report includes descriptions of the identified fracture minerals and their chemical composition. A sequence of fracture mineralisations has been distinguished and provides information of the low to moderate temperature (brittle) geological and hydrogeological evolution at the site. Special focus has been paid to the chemical and stable isotopic composition of calcite to obtain palaeohydrogeological information. Chemical analyses of bulk fracture filling material have been carried out to identify possible sinks for certain elements and also to reveal the presence of minor phases rich in certain elements which have not been possible to detect by X-ray diffraction (XRD). Statistical analysis of the mineralogy in fractures outside deformation zones (i.e. within fracture domains FFM01, FFM02, FFM03 and FFM06) have been carried out concerning variation of fracture mineral distribution at depth and in different fracture domains. Uranium contents and uranium-series isotopes have been analysed on fracture coating material from hydraulically conductive fractures. Such analyses are also available from the groundwaters and the results are combined in order to reveal recent (< 1 Ma) removal/deposition of uranium in the fracture system. The redox conditions in the fracture system have been evaluated based on mineralogical and chemical indicators as well as Moessbauer analyses

  14. Magnesium Isotopic Composition of Subducting Marine Sediments

    Science.gov (United States)

    Hu, Y.; Teng, F. Z.; Plank, T. A.; Huang, K. J.

    2015-12-01

    Subducted marine sediments have recently been called upon to explain the heterogeneous Mg isotopic composition (δ26Mg, ‰) found in mantle wehrlites (-0.39 to +0.09 [1]) in the context of a homogeneous mantle (-0.25 ± 0.07 [2]). However, no systematic measurements of δ26Mg on marine sediments are currently available to provide direct support to this model. To characterize the Mg inputs to global subduction zones, we measured δ26Mg data for a total of 90 marine sediments collected from 12 drill sites outboard of the world's major subduction zones. These sediments span a 1.73‰ range in δ26Mg. The detritus-dominated sediments have δ26Mg (-0.59 to +0.53) comparable to those of weathered materials on continents (e.g. -0.52 to +0.92 [3]), while the calcareous oozes yield δ26Mg (as light as -1.20) more similar to the seawater value (-0.83 [4]). The negative correlation between δ26Mg and CaO/Al2O3 in these sediments indicates the primary control of mineralogy over the Mg isotopic distribution among different sediment types, as carbonates are enriched in light Mg isotopes (-5.10 to -0.40 [5]) whereas clay-rich weathering residues generally have heavier δ26Mg (e.g. up to +0.65 in saprolite [6]). In addition, chemical weathering and grain-size sorting drive sediments to a heavier δ26Mg, as indicated by the broad positive trends between δ26Mg with CIA (Chemical Index of Alteration [7]) and Al2O3/SiO2, respectively. Collectively, the arc systems sampled in this study represent ~30% of global arc length and the extrapolated global Mg flux of subducting marine sediments accounts for ~9% of the yearly Mg riverine input with a flux-weighted average δ26Mg at -0.26. Subduction of these heterogeneous sediments may not cause significant mantle heterogeneity on a global scale, but the highly variable Mg fluxes and δ26Mg of sediments delivered to different trenches are capable of producing local mantle variations. Volcanic rocks sourced from these mantle domains are thus

  15. Martian Surface Mineralogy from Rovers with Spirit, Opportunity, and Curiosity

    Science.gov (United States)

    Morris, Richard V.

    2016-01-01

    Beginning in 2004, NASA has landed three well-instrumented rovers on the equatorial martian surface. The Spirit rover landed in Gusev crater in early January, 2004, and the Opportunity rover landed on the opposite side of Mars at Meridian Planum 21 days later. The Curiosity rover landed in Gale crater to the west of Gusev crater in August, 2012. Both Opportunity and Curiosity are currently operational. The twin rovers Spirit and Opportunity carried Mossbauer spectrometers to determine the oxidation state of iron and its mineralogical composition. The Curiosity rover has an X-ray diffraction instrument for identification and quantification of crystalline materials including clay minerals. Instrument suites on all three rovers are capable of distinguishing primary rock-forming minerals like olivine, pyroxene and magnetite and products of aqueous alteration in including amorphous iron oxides, hematite, goethite, sulfates, and clay minerals. The oxidation state of iron ranges from that typical for unweathered rocks and soils to nearly completely oxidized (weathered) rocks and soils as products of aqueous and acid-sulfate alteration. The in situ rover mineralogy also serves as ground-truth for orbital observations, and orbital mineralogical inferences are used for evaluating and planning rover exploration.

  16. Late Quaternary stratigraphy, sedimentology, and geochemistry of an underfilled lake basin in the Puna (north-west Argentina)

    Science.gov (United States)

    McGlue, Michael M.; Cohen, Andrew S.; Ellis, Geoffrey S.; Kowler, Andrew L.

    2013-01-01

    Depositional models of ancient lakes in thin-skinned retroarc foreland basins rarely benefit from appropriate Quaternary analogues. To address this, we present new stratigraphic, sedimentological and geochemical analyses of four radiocarbon-dated sediment cores from the Pozuelos Basin (PB; northwest Argentina) that capture the evolution of this low-accommodation Puna basin over the past ca. 43 cal kyr. Strata from the PB are interpreted as accumulations of a highly variable, underfilled lake system represented by lake-plain/littoral, profundal, palustrine, saline lake and playa facies associations. The vertical stacking of facies is asymmetric, with transgressive and thin organic-rich highstand deposits underlying thicker, organic-poor regressive deposits. The major controls on depositional architecture and basin palaeogeography are tectonics and climate. Accommodation space was derived from piggyback basin-forming flexural subsidence and Miocene-Quaternary normal faulting associated with incorporation of the basin into the Andean hinterland. Sediment and water supply was modulated by variability in the South American summer monsoon, and perennial lake deposits correlate in time with several well-known late Pleistocene wet periods on the Altiplano/Puna plateau. Our results shed new light on lake expansion–contraction dynamics in the PB in particular and provide a deeper understanding of Puna basin lakes in general.

  17. Offshore sediments record the history of onshore iron ore mining in Goa State, India.

    Science.gov (United States)

    Sebastian, Tyson; Nath, B Nagender; Naik, Sangeeta; Borole, D V; Pierre, Salou; Yazing, Armoury Kazip

    2017-01-30

    Environmental magnetic and geochemical analyses combined with (210)Pb dating were carried out on a sediment core off Goa from Arabian Sea to reconstruct the sedimentation history of last three and a half centuries and to investigate the impact of onshore iron ore mining on the offshore sedimentation. A drastic increase in sedimentation rate and mineral magnetic concentration parameters divides the core into two units (1 & 2) at a depth of 41cm (1982CE). The high magnetic susceptibility values in Unit 1 sediments are coeval with increased iron ore production on land and illustrate the role of terrestrial mining on the increased offshore sedimentation. The early diagenetic signals were observed in Unit 2 of the core with low concentration parameters, coarse magnetic grain size and magnetically hard mineralogy. The geochemical data of the core also record the Little Ice Age (LIA) climatic events of Dalton and Maunder solar minima. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Stability studies of surficial sediments in the Wilmington-Lindenkohl Canyons area, eastern U.S. margin

    Science.gov (United States)

    Almagor, G.; Bennett, R.H.; Mc Gregor, B.A.; Shephard, L.E.

    1982-01-01

    Stability analysis, based on infinite slope analysis and geotechnical data from a suite of 34 cores collected from the continental slope between Wilmington and Lindenkohl Canyons, indicates that the Quaternary surficial silty clay sediments on gentle slopes are stable; that sediment stability on steeper slopes (14??-19??) is marginal; and that on precipitous slopes (>50??) only a thin veneer of unconsolidated sediments can exist. Small earthquake-induced accelerations or the effects of internal waves can result in slope sediment instabilities. ?? 1982 A. M. Dowden, Inc.

  19. Physical properties of muddy sediments from French Guiana

    Science.gov (United States)

    Caillaud, J.; Lesourd, L.; Philippe, S.; Gontharet, S.; Sarrazin, M.; Gardel, A.

    2017-01-01

    The North West migration of long and discontinuous mud banks along the French Guiana coast has been extensively studied during the past years, in particular with a large-scale vision, which consequently has integrated morpho and hydrodynamic data. The aims of the present paper were to use intrinsic sediment properties (grain-size, mineralogy, concentration, and cohesion) to (1) highlight the sedimentary conditions during the consolidation processes from fluid deposit to vegetation development, and (2) verify the apparent homogeneously derived sedimentary facies. Two intertidal transects, Macouria and Cayenne, were compared from the coast to offshore. Their altitude averages of 1 m and 2.8 m above mean sea level, respectively, were different enough to compare the influence of the hydrodynamic impact and emersion time on their sediment properties. The latter, i.e. grain size distribution, mineralogical content, mud concentration, and shear strength (cohesion), were determined from sampled surface sediments (first cm) and along sediment cores (20-30 cm depth) from each transect. A specific X-ray technique was applied to the whole core to differentiate clearly its thin layers. On both intertidal sites, the grain size dominated by the fine silt fraction (2-20 μm) and the bulk mineralogy characterized by five major minerals (quartz, feldspars, chlorite, illite, and kaolinite) appeared homogeneous along both transects and cores. In spite of this apparent uniformity of particle size and mineralogical parameters, as well as for visual observation along the core, high precision X-rays still showed a cyclic sedimentation at a micro-scale level. This cyclicity with intercalation of fine layers was related to distinct dynamic deposits marked by both tidal processes and hydrodynamic factors (swell propagation). The cohesion and concentration results were dependent on the topography, where high topography was characterized by sediments with high cohesion and concentration values

  20. Quaternary Evolution of Karliova Triple Junction

    Science.gov (United States)

    Sançar, Taylan; Zabcı, Cengiz; Akyüz, H. Serdar

    2013-04-01

    The arguments to explain Quaternary evolution of Karlıova Triple Junction (KTJ) depends upon two different analogue models. The compressional type of Prandtl Cell Model (PCM) and 60 km wide shear zone with concomitant counter clockwise block rotation used to modelled for west and east of the KTJ respectively. The data for the model of west of the KTJ acquired by extensive field studies, and quantified geomorphic features. Compressional PCM put forward that behavior of slip lines controlled by boundary faults. But the model is not enough to explain slip distribution, age relation of them. At west of the KTJ boundary faults presented by eastern most segments of the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ). Slip lines, however, presented by Bahçeli and Toklular faults. Both field studies and morphometric analyses undisputedly set forth that there are two different fault types between the NAFZ and EAFZ. The most strain loaded fault type, which are positioned near the NAFZ, start as a strike-slip fault and when it turn to SE its sense of motion change to oblique normal due to changing orientation of principal stress axes. The new orientation of stress axes exposed in the field as a special kind of caprock -cuesta-. The younger slip lines formed very close to junction point and accommodate less slip. Even though slip trajectories started from the boundary faults in compressional PCM, at the west of KTJ, right lateral trajectories more clearly formed close the NAFZ and left lateral trajectories, relatively less strain loaded fault type, are poorly formed close the EAFZ . We think that, this differences between KTJ and compressional PCM result from the distinction of velocity of boundary faults. East of the KTJ governed by completely different mechanism. The region controlled two main fault systems. The Varto Fault Zone (VFZ), the eastern branch of the KTJ, and Murat Fault (MF) delimited the region from north and south respectively. The

  1. Quaternary Magmatism in the Cascades - Geologic Perspectives

    Science.gov (United States)

    Hildreth, Wes

    2007-01-01

    Foreward The Cascade magmatic arc is a belt of Quaternary volcanoes that extends 1,250 km from Lassen Peak in northern California to Meager Mountain in Canada, above the subduction zone where the Juan de Fuca Plate plunges beneath the North American Plate. This Professional Paper presents a synthesis of the entire volcanic arc, addressing all 2,300 known Quaternary volcanoes, not just the 30 or so visually prominent peaks that comprise the volcanic skyline. Study of Cascade volcanoes goes back to the geological explorers of the late 19th century and the seminal investigations of Howel Williams in the 1920s and 1930s. However, major progress and application of modern scientific methods and instrumentation began only in the 1970s with the advent of systematic geological, geophysical, and geochemical studies of the entire arc. Initial stimulus from the USGS Geothermal Research Program was enhanced by the USGS Volcano Hazards Program following the 1980 eruption of Mount St. Helens. Together, these two USGS Programs have provided more than three decades of stable funding, staffing, and analytical support. This Professional Paper summarizes the resultant USGS data sets and integrates them with the parallel contributions of other investigators. The product is based upon an all-encompassing and definitive geological database, including chemical and isotopic analyses to characterize the rocks and geochronology to provide the critical time constraints. Until now, this massive amount of data has not been summarized, and a systematic and uniform interpretation firmly grounded in geological fact has been lacking. Herein lies the primary utility of this Cascade volume. It not only will be the mandatory starting point for new workers, but also will provide essential geological context to broaden the perspectives of current investigators of specific Cascade volcanoes. Wes Hildreth's insightful understanding of volcanic processes and his uncompromising scientific integrity make him

  2. [Mineralogy and genesis of mixed-layer clay minerals in the Jiujiang net-like red soil].

    Science.gov (United States)

    Yin, Ke; Hong, Han-Lie; Li, Rong-Biao; Han, Wen; Wu, Yu; Gao, Wen-Peng; Jia, Jin-Sheng

    2012-10-01

    Mineralogy and genesis were investigated using X-ray diffraction (XRD), Fourier infrared absorption spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM) to understand the mineralogy and its genesis significance of mixed-layer clay minerals in Jiujiang red soil section. XRD and FTIR results show that the net-like red soil sediments are composed of illite, kaolinite, minor smectite and mixed-layer illite-smectite and minor mixed-layer kaolinite-smectite. HRTEM observation indicates that some smectite layers have transformed into kaolinite layers in net-like red soil. Mixed-layer illite-smectite is a transition phase of illite transforming into smectite, and mixed-layer kaolinite-smectite is a transitional product relative to kaolinite and smectite. The occurrence of two mixed-layer clay species suggests that the weathering sequence of clay minerals in net-like red soil traversed from illite to mixed-layer illite-smectite to smectite to mixed-layer kaolinite-smectite to kaolinite, which indicates that net-like red soil formed under a warm and humid climate with strengthening of weathering.

  3. Geological Controls on Mineralogy and Geochemistry of an Early Permian Coal from the Songshao Mine, Yunnan Province, Southwestern China

    Directory of Open Access Journals (Sweden)

    Ruixue Wang

    2016-07-01

    Full Text Available This paper discusses the content, distribution, modes of occurrence, and enrichment mechanism of mineral matter and trace elements of an Early Permian coal from Songshao (Yunnan Province, China by means of coal-petrological, mineralogical, and geochemical techniques. The results show that the Songshao coal is characterized by high total and organic sulfur contents (3.61% and 3.87%, respectively. Lithium (170.39 μg/g and Zr (184.55 μg/g are significantly enriched in the Songshao coal, and, to a lesser extent, elements such as Hg, La, Ce, Nd, Th, Sr, Nb, Sn, Hf, V, and Cr are also enriched. In addition to Hg and Se that are enriched in the roof and floor strata of the coal seam, Li, La, Ce, Pr, Nd, Sm, Gd, Y, Cd, and Sb are slightly enriched in these host rocks. Compared to the upper continental crust, rare earth elements and yttrium in the host rocks and coal samples are characterized by a light-REE enrichment type and have negative Eu, positive Ce and Gd anomalies. Major minerals in the samples of coal, roof, and floor are boehmite, clay minerals (kaolinite, illite, and mixed layer illite-smectite, pyrite, and anatase. Geochemical and mineralogical anomalies of the Songshao coal are attributed to hydrothermal fluids, seawater, and sediment-source rocks.

  4. Geology and geochemistry of gas-charged sediment on Kodiak Shelf, Alaska

    Science.gov (United States)

    Hampton, M.A.; Kvenvolden, K.A.

    1981-01-01

    Methane concentrations in some sediment cores from the Kodiak Shelf and adjacent continental slope increase with depth by three or four orders of magnitude and exceed the solubility in water at ambient conditions. Acoustic anomalies in seismic-reflection records imply that methane-rich sediment is widespread. Molecular composition of hydrocarbon gases and isotopic composition of methane indicate gas formation by shallow biogenic processes. Stratigraphic positions of acoustic anomalies in Quaternary glacial and posttransgressive sediments suggest that these units are likely sources of gas. A seep along the extension of a fault may be gas venting from a deeper thermogenic source. ?? 1981 A.M. Dowden, Inc.

  5. Record of a Mid-Pleistocene depositional anomaly in West Antarctic continental margin sediments: an indicator for ice-sheet collapse?

    Science.gov (United States)

    Hillenbrand, C.-D.; Kuhn, G.; Frederichs, T.

    2009-06-01

    Modern global warming is likely to cause future melting of Earth's polar ice sheets that may result in dramatic sea-level rise. A possible collapse of the West Antarctic Ice Sheet (WAIS) alone, which is considered highly vulnerable as it is mainly based below sea level, may raise global sea level by up to 5-6 m. Despite the importance of the WAIS for changes in global sea level, its response to the glacial-interglacial cycles of the Quaternary is poorly constrained. Moreover, the geological evidence for the disintegration of the WAIS at some time within the last ca. 750 kyr, possibly during Marine Isotope Stage (MIS) 11 (424-374 ka), is ambiguous. Here we present physical properties, palaeomagnetic, geochemical and clay mineralogical data from a glaciomarine sedimentary sequence that was recovered from the West Antarctic continental margin in the Amundsen Sea and spans more than the last 1 Myr. Within the sedimentary sequence, proxies for biological productivity (such as biogenic opal and the barium/aluminum ratio) and the supply of lithogenic detritus from the West Antarctic hinterland (such as ice-rafted debris and clay minerals) exhibit cyclic fluctuations in accordance with the glacial-interglacial cycles of the Quaternary. A prominent depositional anomaly spans MIS 15-MIS 13 (621-478 ka). The proxies for biological productivity and lithogenic sediment supply indicate that this interval has the characteristics of a single, prolonged interglacial period. Even though no proxy suggests environmental conditions much different from today, we conclude that, if the WAIS collapsed during the last 800 kyr, then MIS 15-MIS 13 was the most likely time period. Apparently, the duration rather than the strength of interglacial conditions was the crucial factor for the WAIS drawdown. A comparison with various marine and terrestrial climate archives from around the world corroborates that unusual environmental conditions prevailed throughout MIS 15-MIS 13. Some of these

  6. Iron Solubility Depending on the Mineralogical Composition of Dust Particles

    Science.gov (United States)

    Journet, E.; Desboeufs, K.; Chevaillier, S.; Caquineau, S.

    2008-12-01

    Dust deposition in open ocean is recognised as an important supply of iron for phytoplankton community. Various previous studies have shown an extremely variable solubility (0,01-80%) and numerous factors influencing this solubility, as suspended particules concentration, chemical and photochemical atmospheric process, aerosol sources (Maholwald et al., 2005). Despite these numerous studies, any factor of influence seems to be dominant enough to enable a comprehensive parameterization of iron solubility. Recently, dissolution experiment have been conducted on pure mineral that composed dust, like illite, feldpars, smectite and iron (hydr-)oxide. This study has shown that iron solubility is extremely dependent on the mineral that is considered. Iron coming from aluminosilicates is much more soluble that iron derived from iron (hyd-)oxides (Journet et al., 2008). According to these results, dissolution experiments have been led on dust particles collected in different source areas, in West Africa, and after transport, in tropical Atlantic Ocean. These experiments show that iron solubility is very low, always under 0,6%, in agreement with others observations in these regions (e.g. Baker et al., 2006). Furthermore, from bulk mineralogical analysis of the dust samples, iron solubility in source areas seems exclusively dependent on the mineralogical composition of dust particle. The greater iron solubilities (0,3%) corresponds to dust originated from central Sahara (Algeria, Lybia, Tunisia) where smectite are abundant in comparison to the others studied area (Sahel and Western Sahara) where iron mainly comes from iron (hydr-)oxide and illite. In this case, iron solubility does not exceed 0,13%. From comparison between these results and the lab data issued from Journet et al. (2008), a parameterization to estimate iron solubility from mineralogical composition of dust has been established and validated. Far from the source, iron solubility is usually greater than dust

  7. An unpublished text of Jovellanos about mineralogy Notas inéditas de Jovellanos sobre mineralogía

    Directory of Open Access Journals (Sweden)

    Jorge ORDAZ GARGALLO

    2012-01-01

    Full Text Available An unpublished manuscript of Gaspar Melchor de Jovellanos about the history of mineralogy, written during his captivity in Bellver Castle (Palma de Mallorca is presented and analyzed. In this writing the importance of the chemical knowledge as a source of other branches of science and its applications in different fields of agriculture, mining and industry is considered. The author made a historical synthesis reviewing the men of science that contributed in a great extent to the advance of the chemistry and mineralogy. The text clearly supports the new contributions of Lavoisier and other supporters of experimentation as a scientific method, which agrees with Jovellanos’ ideas about the development of the «useful» sciences for the progress of the countries.Se presenta y analiza un manuscrito inédito de Gaspar Melchor de Jovellanos sobre la historia de la mineralogía, que redactó durante su cautiverio en el Castillo de Bellver (Palma de Mallorca. En el escrito considera de gran importancia los conocimientos químicos como fuente de otras ramas del saber científico y sus aplicaciones en distintos ámbitos de la agricultura, minería e industria. El autor hace una síntesis histórica repasando los hombres de ciencia que en mayor medida contribuyeron al avance de la química y la mineralogía. El texto apoya claramente las nuevas aportaciones de Lavoisier y otros químicos partidarios de la experimentación como método científico, y es acorde con las ideas de Jovellanos acerca del cultivo de las ciencias «útiles» para el progreso de los pueblos.

  8. An unpublished text of Jovellanos about mineralogy Notas inéditas de Jovellanos sobre mineralogía

    OpenAIRE

    Ordaz Gargallo, Jorge; Gutiérrez Claverol, Manuel; De Lorenzo Álvarez, Elena

    2012-01-01

    An unpublished manuscript of Gaspar Melchor de Jovellanos about the history of mineralogy, written during his captivity in Bellver Castle (Palma de Mallorca) is presented and analyzed. In this writing the importance of the chemical knowledge as a source of other branches of science and its applications in different fields of agriculture, mining and industry is considered. The author made a historical synthesis reviewing the men of science that contributed in a great extent to the advance of t...

  9. Permafrost sequences on Kurungnakh Island, Lena Delta (NE Siberia, Russia) as key site of the late Quaternary environmental history of West Beringia

    Science.gov (United States)

    Wetterich, S.; Kuzmina, S.; Andreev, A. A.; Kienast, F.; Meyer, H.; Schirrmeister, L.; Kuznetsova, T.; Sierralta, M.

    2009-04-01

    Late Quaternary permafrost sequences are widely distributed in the arctic lowlands of Siberia. Because the existence of permafrost has been sensitive to climate changes during the Quaternary past, such frozen deposits are regarded as an archive of palaeoenvironmental dynamics. Late Quaternary palaeoenvironments of the Siberian Arctic were reconstructed by combining data from several fossil bioindicators (pollen, plant macro-fossils, ostracods, insects, and mammal bones) with sedimentological and cryolithological data from permafrost deposits. The late Pleistocene to Holocene sequence on Kurungnakh Island (Lena Delta, NE Siberia) reflects the environmental history of West Beringia and covers glacial/interglacial and stadial/interstadial climate variations with a focus on the Middle Weichselian interstadial (50-32 kyr BP). The record mirrors the development of periglacial landscapes under changing sedimentation regimes which were meandering fluvial during the Early Weichselian, colluvial or proluvial on gently inclined plaines during the Middle and Late Weichselian, and thermokarst-affected during the Holocene. Palaeoecological records indicate the existence of tundra-steppe vegetation under cold continental climate conditions during the Middle Weichselian interstadial. Due to sedimentation gaps in the sequence between 32 and 17 kyr BP and 17 and 8 kyr BP, the Late Weichselian stadial is incompletely represented in the studied outcrops. Nevertheless, by several palaeoecological indications arctic tundra-steppe vegetation under extremely cold-arid conditions prevailed during the late Pleistocene. The tundra-steppe disappeared completely due to lasting paludification during the Holocene. Initially subarctic shrub tundra formed, which later retreated in course of the late Holocene cooling.

  10. Sedimentation History of Neogene Lacustrine Sediments of Suseocka Bela Stena Based on Geochemical Parameters (Valjevo-Mionica Basin, Serbia)

    Institute of Scientific and Technical Information of China (English)

    Aleksandra (S)AJNOV1(C); Vladimir SIMI(C); Branimir JOVAN(C)I(C)EVI(C); Olga CVETKOVI(C); Radovan DIMITRIJEVI(C); Nenad GRUBIN

    2008-01-01

    Sediments of the western part of the Valjevo-Mionica basin (Serbia) were examined both geochemically and mineralogically to explain, on the basis of their sedimentological characteristics, the causes of changes in their qualitative and quantitative composition. A total of 62 samples obtained from the drillhole at depths up to 400 m was investigated. Using correlation of the obtained data, six geochemical zones were defined, two of which being specially distinguished by their mineralogical, geochemical and sedimentological characteristics. The first one, upper zone A, consists of banded marlstones interbedded with clay and oil shales and is characterized by presence of analcite and searlesite. These minerals and very high contents of Na2O indicate sedimentation in alkaline conditions with increased salinity in arid climate. That provided pronounced water stratification, as well as higher bioproductivity in the basin and sedimentary organic matter preservation. Therefore, the zone A sediments are characterized by high organic matter contents of the type which provides good potential for production of liquid hydrocarbons. Another specific zone, zone F, contains sediments with very high MgO, K2O and Li concentrations. Their geochemical correlation, as well as almost complete absence of illite in this zone, indicates the presence of interstratified clay mineral type illite-saponite (lithium-bearing Mg-smectite).

  11. Mineralogy of an ancient lacustrine mudstone succession from the Murray formation, Gale crater, Mars

    Science.gov (United States)

    Rampe, E. B.; Ming, D. W.; Blake, D. F.; Bristow, T. F.; Chipera, S. J.; Grotzinger, J. P.; Morris, R. V.; Morrison, S. M.; Vaniman, D. T.; Yen, A. S.; Achilles, C. N.; Craig, P. I.; Des Marais, D. J.; Downs, R. T.; Farmer, J. D.; Fendrich, K. V.; Gellert, R.; Hazen, R. M.; Kah, L. C.; Morookian, J. M.; Peretyazhko, T. S.; Sarrazin, P.; Treiman, A. H.; Berger, J. A.; Eigenbrode, J.; Fairén, A. G.; Forni, O.; Gupta, S.; Hurowitz, J. A.; Lanza, N. L.; Schmidt, M. E.; Siebach, K.; Sutter, B.; Thompson, L. M.

    2017-08-01

    acid-sulfate alteration on Earth. We hypothesize that multiple influxes of mildly to moderately acidic pore fluids resulted in diagenesis of the Murray formation and the observed mineralogical and geochemical variations. The preservation of some minerals that are highly susceptible to dissolution at low pH (e.g., mafic minerals and fluorapatite) suggests that acidic events were not long-lived and that fluids may not have been extremely acidic (pH > 2). Alternatively, the observed mineralogical variations within the succession may be explained by deposition in lake waters with variable Eh and/or pH, where the lowermost sediments were deposited in an oxidizing, perhaps acidic lake setting, and sediments deposited in the upper Pahrump Hills and Marias Pass were deposited lake waters with lower Eh and higher pH.

  12. Fluctuation in glacial and interglacial sediment discharge of the River Indus as seen in the core from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Hashimi, N.H.

    Sediment core from the upper continental slope off Saurashtra Coast has been analysed for CaCO sub(3) and coarse fraction contents in addition to planktonic foraminifera and clay mineralogy. Based on CaCO sub(3) and planktonic foraminiferal data a...

  13. Correlation of sedimentary units from grain-size and mineralogic analyses as a tool for constraining trench interpretations in palaeoseismology

    Science.gov (United States)

    Ezquerro, Lope; Liesa, Carlos L.; Simón, José L.; Arlegui, Luis E.; Luzón, Aránzazu; Lafuente, Paloma

    2014-11-01

    In palaeoseismological trench studies, precise correlation of sedimentary units between fault blocks has an unquestionable value for accurately inferring the amounts of coseismic displacement and hence for assessing seismic hazard. A methodology based on laser analysis of particle size and mineralogic composition by X-ray diffraction is proposed in order to strengthen the correlation of sedimentary units in a trench excavated across the Concud Fault (central Iberian Chain, Spain). The surveyed sediments show sharp and multiple lateral facies changes, as well as inconsistent optically stimulated luminescence (OSL) ages. The results reinforce the correlation based on field inspection of lithologic and sedimentologic features. Moreover, they allow interpretation of rejuvenation of OSL ages of samples in the upthrown fault block, which has been attributed to partial erosion of sedimentary units, as evidenced by their smaller thickness and erosive boundaries. The correlated units are then used to estimate coseismic displacements for three palaeoseismic events.

  14. Mineralogy and geochemistry of xenoliths in the Eocene volcanic rocks from southwest of Jandaq

    Directory of Open Access Journals (Sweden)

    Samineh Rajabi

    2013-04-01

    Full Text Available The Eocene volcanic rocks from the southwest of the Jandaq (Kuh-e-Godar-e-Siah, Central-East Iran micro-continent are andesitic basalt and andesite in composition. These rocks contain xenoliths with granulitic mineralogy. Mineral assemblage of these xenoliths is plagioclase + phlogopite + corundum + sillimanite + chlorite + phengite with granublastic, poiklioblastic and foliated textures in the pick metamorphic condition. Thermometry of phlogopite in these xenoliths suggests the average temperature 782oC. The characteristics of the xenoliths are consistent with the granolitic facies metamorphism of the Al-saturated Si-undersaturated crustal sediments at the lower crust condition. Melting of these granulites forms the magma which crystallized the S-type granitoids. Differentiation and crystallization of this magma causes the S-type granite formation. Therefore, the S-type granites in the study area are probably generated from melting of the granulites parts of which brought to the surface as xenoliths by Eocene magmatism in south of the Jandaq (Kuh-e-Godar-e-Siah. S-type granites in the study area are located along the Doruneh, Chupanan and Aeirakan faults in the Aeirakan area and Jandaq ophiolite. These granites are the source of uranium, thorium and uranium ore in southwest of the Aeirakan mountain.

  15. Río Tinto: A Geochemical and Mineralogical Terrestrial Analogue of Mars

    Directory of Open Access Journals (Sweden)

    Ricardo Amils

    2014-09-01

    Full Text Available The geomicrobiological characterization of the water column and sediments of Río Tinto (Huelva, Southwestern Spain have proven the importance of the iron and the sulfur cycles, not only in generating the extreme conditions of the habitat (low pH, high concentration of toxic heavy metals, but also in maintaining the high level of microbial diversity detected in the basin. It has been proven that the extreme acidic conditions of Río Tinto basin are not the product of 5000 years of mining activity in the area, but the consequence of an active underground bioreactor that obtains its energy from the massive sulfidic minerals existing in the Iberian Pyrite Belt. Two drilling projects, MARTE (Mars Astrobiology Research and Technology Experiment (2003–2006 and IPBSL (Iberian Pyrite Belt Subsurface Life Detection (2011–2015, were developed and carried out to provide evidence of subsurface microbial activity and the potential resources that support these activities. The reduced substrates and the oxidants that drive the system appear to come from the rock matrix. These resources need only groundwater to launch diverse microbial metabolisms. The similarities between the vast sulfate and iron oxide deposits on Mars and the main sulfide bioleaching products found in the Tinto basin have given Río Tinto the status of a geochemical and mineralogical Mars terrestrial analogue.

  16. Low Hesperian PCO2 constrained from in situ mineralogical analysis at Gale Crater, Mars

    Science.gov (United States)

    Bristow, Thomas F.; Haberle, Robert M.; Blake, David F.; Des Marais, David J.; Eigenbrode, Jennifer L.; Fairén, Alberto G.; Grotzinger, John P.; Stack, Kathryn M.; Mischna, Michael A.; Rampe, Elizabeth B.; Siebach, Kirsten L.; Sutter, Brad; Vaniman, David T.; Vasavada, Ashwin R.

    2017-01-01

    Carbon dioxide is an essential atmospheric component in martian climate models that attempt to reconcile a faint young sun with planetwide evidence of liquid water in the Noachian and Early Hesperian. In this study, we use mineral and contextual sedimentary environmental data measured by the Mars Science Laboratory (MSL) Rover Curiosity to estimate the atmospheric partial pressure of CO2 (PCO2) coinciding with a long-lived lake system in Gale Crater at ∼3.5 Ga. A reaction–transport model that simulates mineralogy observed within the Sheepbed member at Yellowknife Bay (YKB), by coupling mineral equilibria with carbonate precipitation kinetics and rates of sedimentation, indicates atmospheric PCO2 levels in the 10s mbar range. At such low PCO2 levels, existing climate models are unable to warm Hesperian Mars anywhere near the freezing point of water, and other gases are required to raise atmospheric pressure to prevent lake waters from being lost to the atmosphere. Thus, either lacustrine features of Gale formed in a cold environment by a mechanism yet to be determined, or the climate models still lack an essential component that would serve to elevate surface temperatures, at least locally, on Hesperian Mars. Our results also impose restrictions on the potential role of atmospheric CO2 in inferred warmer conditions and valley network formation of the late Noachian. PMID:28167765

  17. Magnetic and Moessbauer Studies of Quaternary Argentine Loessic Soils and Paleosols

    Energy Technology Data Exchange (ETDEWEB)

    Mercader, R. C., E-mail: mercader@fisica.unlp.edu.ar; Sives, F. R. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Imbellone, P. A. [Universidad Nacional de La Plata, Instituto de Geomorfologia y Suelos (Argentina); Vandenberghe, R. E. [Ghent University, NUMAT, Department of Subatomic and Radiation Physics (Belgium)

    2005-02-15

    This paper is a review of the current status about the remaining problems that are found in the investigation of the Quaternary Argentine soils and loessic sediments, and the way that Moessbauer studies can assist in solving them. There are two main types of investigations that make use of the magnetic response of the samples to correlate them with information gathered by other methods. On the one hand, there is the stratigraphic and chronological research, which is of importance from the geological and paleontological points of view. On the other hand, the paleoclimatic records, of significance toward a possible model of the past climate, are also studied because of their close relation to the sediments history. However, there is not yet a model that can tell the difference between the modifications due to the climatic conditions at the time when the soils were buried from processes that occurred after burial. Some examples are given that show that Moessbauer studies can be applied with a certain degree of success when cross-checked with magnetic measurements toward understanding the processes that occurred in alluvial B (paleosols) and C horizons (loess) from the eastern part of Buenos Aires Province. Although the application of Moessbauer studies to hydromorphic processes in soils is not straightforward, there are cases in which Moessbauer spectroscopy, if applied properly and correlated with other techniques, is able to characterize the type of iron oxides existing in the materials and thus assist theories about its origin and history.

  18. Palaeoenvironmental dynamics inferred from late Quaternary permafrost deposits on Kurungnakh Island, Lena Delta, Northeast Siberia, Russia

    Science.gov (United States)

    Wetterich, Sebastian; Kuzmina, Svetlana; Andreev, Andrei A.; Kienast, Frank; Meyer, Hanno; Schirrmeister, Lutz; Kuznetsova, Tatyana; Sierralta, Melanie

    2008-08-01

    Late Quaternary palaeoenvironments of the Siberian Arctic were reconstructed by combining data from several fossil bioindicators (pollen, plant macro-fossils, ostracods, insects, and mammal bones) with sedimentological and cryolithological data from permafrost deposits. The record mirrors the environmental history of Beringia and covers glacial/interglacial and stadial/interstadial climate variations with a focus on the Middle Weichselian interstadial (50-32 kyr BP). The late Pleistocene to Holocene sequence on Kurungnakh Island reflects the development of periglacial landscapes under changing sedimentation regimes which were meandering fluvial during the Early Weichselian, colluvial or proluvial on gently inclined plaines during the Middle and Late Weichselian, and thermokarst-affected during the Holocene. Palaeoecological records indicate the existence of tundra-steppe vegetation under cold continental climate conditions during the Middle Weichselian interstadial. Due to sedimentation gaps in the sequence between 32 and 17 kyr BP and 17 and 8 kyr BP, the Late Weichselian stadial is incompletely represented in the studied outcrops. Nevertheless, by several palaeoecological indications arctic tundra-steppe vegetation under extremely cold-arid conditions prevailed during the late Pleistocene. The tundra-steppe disappeared completely due to lasting paludification during the Holocene. Initially subarctic shrub tundra formed, which later retreated in course of the late Holocene cooling.

  19. Tropical Rain Forest and Climate Dynamics of the Atlantic Lowland, Southern Brazil, during the Late Quaternary

    Science.gov (United States)

    Behling, Hermann; Negrelle, Raquel R. B.

    2001-11-01

    Palynological analysis of a core from the Atlantic rain forest region in Brazil provides unprecedented insight into late Quaternary vegetational and climate dynamics within this southern tropical lowland. The 576-cm-long sediment core is from a former beach-ridge "valley," located 3 km inland from the Atlantic Ocean. Radio-carbon dates suggest that sediment deposition began prior to 35,000 14C yr B.P. Between ca. 37,500 and ca. 27,500 14C yr B.P. and during the last glacial maximum (LGM; ca. 27,500 to ca. 14,500 14C yr B.P.), the coastal rain forest was replaced by grassland and patches of cold-adapted forest. Tropical trees, such as Alchornea, Moraceae/Urticaceae, and Arecaceae, were almost completely absent during the LGM. Furthermore, their distributions were shifted at least 750 km further north, suggesting a cooling between 3°C and 7°C and a strengthening of Antarctic cold fronts during full-glacial times. A depauperate tropical rain forest developed as part of a successional sequence after ca. 12,300 14C yr B.P. There is no evidence that Araucaria trees occurred in the Atlantic lowland during glacial times. The rain forest was disturbed by marine incursions during the early Holocene period until ca. 6100 14C yr B.P., as indicated by the presence of microforaminifera. A closed Atlantic rain forest then developed at the study site.

  20. Quaternary ammonium compounds (QACs): a review on occurrence, fate and toxicity in the environment.

    Science.gov (United States)

    Zhang, Chang; Cui, Fang; Zeng, Guang-ming; Jiang, Min; Yang, Zhong-zhu; Yu, Zhi-gang; Zhu, Meng-ying; Shen, Liu-qing

    2015-06-15

    Quaternary ammonium compounds (QACs) are widely applied in household and industrial products. Most uses of QACs can be expected to lead to their release to wastewater treatment plants (WWTPs) and then dispersed into various environmental compartments through sewage effluent and sludge land application. Although QACs are considered to be aerobically biodegradable, the degradation is affected by its chemical structures, dissolved oxygen concentration, complexing with anionic surfactants, etc. High abundance of QACs has been detected in sediment and sludge samples due to its strong sorption and resistance to biodegradation under anoxic/anaerobic conditions. QACs are toxic to a lot of aquatic organisms including fish, daphnids, algae, rotifer and microorganisms employed in wastewater treatment systems. And antibiotic resistance has emerged in microorganisms due to excessive use of QACs in household and industrial applications. The occurrence of QACs in the environment is correlated with anthropogenic activities, such as wastewater discharge from WWTPs or single source polluters, and sludge land application. This article also reviews the analytical methods for determination of QACs in environmental compartments including surface water, wastewater, sewage sludge and sediments. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Origin of Quaternary Red Clay of Southern Anhui Province

    Institute of Scientific and Technical Information of China (English)

    HUXUEFENG; YUANGUODONG; 等

    1998-01-01

    The particle-size distribution,heavy mineral constituents and rare earth elements(REE) characteristics of the Quaternary red clay of southern Anhui Province were studied to explore the origin of the clay.The results showed that the clay had some properties of areolian deposits,which co