The First Global Geological Map of Mercury

Science.gov (United States)

Prockter, L. M.; Head, J. W., III; Byrne, P. K.; Denevi, B. W.; Kinczyk, M. J.; Fassett, C.; Whitten, J. L.; Thomas, R.; Ernst, C. M.

2015-12-01

Geological maps are tools with which to understand the distribution and age relationships of surface geological units and structural features on planetary surfaces. Regional and limited global mapping of Mercury has already yielded valuable science results, elucidating the history and distribution of several types of units and features, such as regional plains, tectonic structures, and pyroclastic deposits. To date, however, no global geological map of Mercury exists, and there is currently no commonly accepted set of standardized unit descriptions and nomenclature. With MESSENGER monochrome image data, we are undertaking the global geological mapping of Mercury at the 1:15M scale applying standard U.S. Geological Survey mapping guidelines. This map will enable the development of the first global stratigraphic column of Mercury, will facilitate comparisons among surface units distributed discontinuously across the planet, and will provide guidelines for mappers so that future mapping efforts will be consistent and broadly interpretable by the scientific community. To date we have incorporated three major datasets into the global geological map: smooth plains units, tectonic structures, and impact craters and basins >20 km in diameter. We have classified most of these craters by relative age on the basis of the state of preservation of morphological features and standard classification schemes first applied to Mercury by the Mariner 10 imaging team. Additional datasets to be incorporated include intercrater plains units and crater ejecta deposits. In some regions MESSENGER color data is used to supplement the monochrome data, to help elucidate different plains units. The final map will be published online, together with a peer-reviewed publication. Further, a digital version of the map, containing individual map layers, will be made publicly available for use within geographic information systems (GISs).

Building a Bridge to Deep Time: Sedimentary Systems Across Timescales

Science.gov (United States)

Romans, B.; Castelltort, S.; Covault, J. A.; Walsh, J. P.

2013-12-01

It is increasingly important to understand the complex and interdependent processes associated with sediment production, transport, and deposition at timescales relevant to civilization (annual to millennial). However, predicting the response of sedimentary systems to global environmental change across a range of timescales remains a significant challenge. For example, a significant increase in global average temperature at the Paleocene-Eocene boundary (55.8 Ma) is interpreted to have occurred over millennial timescales; however, the specific response of sedimentary systems (e.g., timing and magnitude of sediment flux variability in river systems) to that forcing is debated. Thus, using such environmental perturbations recorded in sedimentary archives as analogs for ongoing/future global change requires improved approaches to bridging across time. Additionally, the ability to bridge timescales is critical for addressing other questions about sedimentary system behavior, including signal propagation and signal versus ';noise' in the record. The geologic record provides information that can be used to develop a comprehensive understanding of process-response behavior at multiple timescales. The geomorphic ';snapshot' of present-day erosional and depositional landscapes can be examined to reconstruct the history of processes that created the observable configurations. Direct measurement and monitoring of active processes are used to constrain conceptual and numerical models and develop sedimentary system theory. But real-time observations of active Earth-surface processes are limited to the very recent, and how such processes integrate over longer timescales to transform into strata remains unknown. At longer timescales (>106 yr), the stratigraphic record is the only vestige of ancient sedimentary systems. Stratigraphic successions contain a complex record of sediment deposition and preservation, as well as the detrital material that originated in long since denuded

The Europa Global Geologic Map

Science.gov (United States)

Leonard, E. J.; Patthoff, D. A.; Senske, D. A.; Collins, G. C.

2018-06-01

The Europa Global Geologic Map reveals three periods in Europa's surface history as well as an interesting distribution of microchaos. We will discuss the mapping and the interesting implications of our analysis of Europa's surface.

Transitioning Groundwater from an Extractive Resource to a Managed Water Storage Resource: Geology and Recharge in Sedimentary Basins

Science.gov (United States)

Maples, S.; Fogg, G. E.; Maxwell, R. M.; Liu, Y.

2017-12-01

Civilizations have typically obtained water from natural and constructed surface-water resources throughout most of human history. Only during the last 50-70 years has a significant quantity of water for humans been obtained through pumping from wells. During this short time, alarming levels of groundwater depletion have been observed worldwide, especially in some semi-arid and arid regions that rely heavily on groundwater pumping from clastic sedimentary basins. In order to reverse the negative effects of over-exploitation of groundwater resources, we must transition from treating groundwater mainly as an extractive resource to one in which recharge and subsurface storage are pursued more aggressively. However, this remains a challenge because unlike surface-water reservoirs which are typically replenished over annual timescales, the complex geologic architecture of clastic sedimentary basins impedes natural groundwater recharge rates resulting in decadal or longer timescales for aquifer replenishment. In parts of California's Central Valley alluvial aquifer system, groundwater pumping has outpaced natural groundwater recharge for decades. Managed aquifer recharge (MAR) has been promoted to offset continued groundwater overdraft, but MAR to the confined aquifer system remains a challenge because multiple laterally-extensive silt and clay aquitards limit recharge rates in most locations. Here, we simulate the dynamics of MAR and identify potential recharge pathways in this system using a novel combination of (1) a high-resolution model of the subsurface geologic heterogeneity and (2) a physically-based model of variably-saturated, three-dimensional water flow. Unlike most groundwater models, which have coarse spatial resolution that obscures the detailed subsurface geologic architecture of these systems, our high-resolution model can pinpoint specific geologic features and locations that have the potential to `short-circuit' aquitards and provide orders

Collaborative Research: Bringing Problem Solving in the Field into the Classroom: Developing and Assessing Virtual Field Trips for Teaching Sedimentary and Introductory Geology

Science.gov (United States)

Wang, P.; Caldwell, M.

2012-12-01

Coastal Florida offers a unique setting for the facilitation of learning about a variety of modern sedimentary environments. Despite the conflicting concept of "virtual" and "actual" field trip, and the uncertainties associated with the implementation and effectiveness, virtual trips provide likely the only way to reach a large diversified student population and eliminate travel time and expenses. In addition, with rapidly improving web and visualization technology, field trips can be simulated virtually. It is therefore essential to systematically develop and assess the educational effectiveness of virtual field trips. This project is developing, implementing, and assessing a series of virtual field trips for teaching undergraduate sedimentary geology at a large four-year research university and introductory geology at a large two-year community college. The virtual field trip is based on a four-day actual field trip for a senior level sedimentary geology class. Two versions of the virtual field trip, one for advanced class and one for introductory class, are being produced. The educational outcome of the virtual field trip will be compared to that from actual field trip. This presentation summarizes Year 1 achievements of the three-year project. The filming, editing, and initial production of the virtual field trip have been completed. Formative assessments were conducted by the Coalition for Science Literacy at the University of South Florida. Once tested and refined, the virtual field trips will be disseminated through broadly used web portals and workshops at regional and national meetings.

The First USGS Global Geologic Map of Europa

Science.gov (United States)

Leonard, E. J.; Patthoff, D. A.; Senske, D.; Collins, G. C.

2017-12-01

Understanding the global scale geology of Europa is paramount to gaining insight into the potential habitability of this icy world. To this end, work is ongoing to complete a global geological map at the scale of 1:15 million that incorporates data at all resolutions collected by the Voyager and Galileo missions. The results of this work will aid the Europa Clipper mission, now in formulation, by providing a framework for collaborative and synergistic science investigations. To understand global geologic and tectonic relations, a total of 10 geologic units have been defined. These include: Low Albedo Ridge Material (lam)—low albedo material that irregularly surrounds large (>20 km) ridge structures; Ridged plains (pr)—distributed over all latitudes and characterized by subparallel to cross-cutting ridges and troughs visible at high resolution (material (b)—linear to curvilinear zones with a distinct, abrupt albedo change from the surrounding region; Crater material (c), Continuous Crater Ejecta (ce) and Discontinuous Crater Ejecta (dce)—features associated with impact craters including the site of the impact, crater material, and the fall-out debris respectively; Low Albedo Chaos (chl), Mottled Albedo Chaos (chm) and High Albedo Chaos (chh)—disrupted terrain with a relatively uniform low albedo, patchy/variegated albedo, and uniform high albedo appearance respectively; Knobby Chaos (chk) - disrupted terrain with rough and blocky texture occurring in the high latitudes. In addition to the geologic units, our mapping also includes structural features—Ridges, Cycloids, Undifferentiated Linea, Crater Rims, Depression Margins, Dome Margins and Troughs. We also introduce a point feature (at the global scale), Microchaos, to denote small (material. The completed map will constrain the distribution of different Europa terrains and provide a general stratigraphic framework to assess the geologic history of Europa from the regional to the global scale. Here, we

Global Tsunami Database: Adding Geologic Deposits, Proxies, and Tools

Science.gov (United States)

Brocko, V. R.; Varner, J.

2007-12-01

A result of collaboration between NOAA's National Geophysical Data Center (NGDC) and the Cooperative Institute for Research in the Environmental Sciences (CIRES), the Global Tsunami Database includes instrumental records, human observations, and now, information inferred from the geologic record. Deep Ocean Assessment and Reporting of Tsunamis (DART) data, historical reports, and information gleaned from published tsunami deposit research build a multi-faceted view of tsunami hazards and their history around the world. Tsunami history provides clues to what might happen in the future, including frequency of occurrence and maximum wave heights. However, instrumental and written records commonly span too little time to reveal the full range of a region's tsunami hazard. The sedimentary deposits of tsunamis, identified with the aid of modern analogs, increasingly complement instrumental and human observations. By adding the component of tsunamis inferred from the geologic record, the Global Tsunami Database extends the record of tsunamis backward in time. Deposit locations, their estimated age and descriptions of the deposits themselves fill in the tsunami record. Tsunamis inferred from proxies, such as evidence for coseismic subsidence, are included to estimate recurrence intervals, but are flagged to highlight the absence of a physical deposit. Authors may submit their own descriptions and upload digital versions of publications. Users may sort by any populated field, including event, location, region, age of deposit, author, publication type (extract information from peer reviewed publications only, if you wish), grain size, composition, presence/absence of plant material. Users may find tsunami deposit references for a given location, event or author; search for particular properties of tsunami deposits; and even identify potential collaborators. Users may also download public-domain documents. Data and information may be viewed using tools designed to extract and

Geological history of uranium

International Nuclear Information System (INIS)

Niini, Heikki

1989-01-01

Uranium is widely distributed in continental geological environments. The order of magnitude of uranium abundance in felsitic igneous rocks is 2-15 ppm, whereas it is less than 1 ppm in mafic rocks. Sedimentary rocks show a large range: from less than 0.1 ppm U in certain evaporites to over 100 ppm in phosphate rocks and organogenic matter. The content of U in seawater varies from 0.0005 to 0.005 ppm. The isotopic ratio U-238/U-235 is presently 137.5+-0.5, having gradually increased during geological time. The third natural isotope is U-234. On the basis of three fundamental economic criteria for ore reserves assessment (geological assurance, technical feasibility, and the grade and quantity of the deposits), the author finally comes to the following conclusions: Although the global uranium ores are not geologically renewable but continuously mined, they still, due to exploration and technical development, will tend to progressively increase for centuries to come

Global Journal of Geological Sciences: Contact

African Journals Online (AJOL)

Principal Contact. Prof . Barth N. Ekwueme MANAGING EDITOR Global Journal Series Department of Geology, University of Calabar, P. O. Box 3561 Unical P.O. Calabar Cross River State Nigeria Email: bachudo@yahoo.com ...

Relating Gestures and Speech: An analysis of students' conceptions about geological sedimentary processes

Science.gov (United States)

Herrera, Juan Sebastian; Riggs, Eric M.

2013-08-01

Advances in cognitive science and educational research indicate that a significant part of spatial cognition is facilitated by gesture (e.g. giving directions, or describing objects or landscape features). We aligned the analysis of gestures with conceptual metaphor theory to probe the use of mental image schemas as a source of concept representations for students' learning of sedimentary processes. A hermeneutical approach enabled us to access student meaning-making from students' verbal reports and gestures about four core geological ideas that involve sea-level change and sediment deposition. The study included 25 students from three US universities. Participants were enrolled in upper-level undergraduate courses on sedimentology and stratigraphy. We used semi-structured interviews for data collection. Our gesture coding focused on three types of gestures: deictic, iconic, and metaphoric. From analysis of video recorded interviews, we interpreted image schemas in gestures and verbal reports. Results suggested that students attempted to make more iconic and metaphoric gestures when dealing with abstract concepts, such as relative sea level, base level, and unconformities. Based on the analysis of gestures that recreated certain patterns including time, strata, and sea-level fluctuations, we reasoned that proper representational gestures may indicate completeness in conceptual understanding. We concluded that students rely on image schemas to develop ideas about complex sedimentary systems. Our research also supports the hypothesis that gestures provide an independent and non-linguistic indicator of image schemas that shape conceptual development, and also play a role in the construction and communication of complex spatial and temporal concepts in the geosciences.

OneGeology- A Global Geoscience Data Platform

Science.gov (United States)

Harrison, M.; Komac, M.; Duffy, T.; Robida, F.; Allison, M. L.

2014-12-01

OneGeology (1G) is an initiative of Geological Survey Organisations (GSOs) around the globe that dates back to 2007. Since then, OneGeology has been a leader in developing geological online map data using GeoSciML- an international interoperability standard for the exchange of geological data. Increased use of this new standard allows geological data to be shared and integrated across the planet among organisations. One of the goals of OneGeology is an exchange of know-how with the developing world, shortening the digital learning curve. In autumn 2013 OneGeology was transformed into a Consortium with a clearly defined governance structure, making it more transparent, its operation more sustainable and its membership more open where in addition to GSOs, other types of organisations that create and use geoscience data can join and contribute. The next stage of the OneGeology initiative is focused on increasing the openness and richness of that data from individual countries to create a multi-thematic global geological data resource about the rocks beneath our feet. Authoritative geoscience information will help to mitigate natural disasters, explore for resources (water, minerals and energy) and identify risks to human health on a planetary scale with the aim of 1G to increase awareness of the geosciences and their relevance among professionals and general public- to be part of the solution. We live in a digital world that enables prompt access to vast amounts of open access data. Understanding our world, the geology beneath our feet and environmental challenges related to geology calls for accessibility of geoscience data and the OneGeology Portal (portal.onegeology.org) is the place to find them.

Shallow subsurface geology and Vs characteristics of sedimentary units throughout Rasht City, Iran

Directory of Open Access Journals (Sweden)

Behzad Mehrabi

2009-06-01

Full Text Available The Manjil-Rudbar earthquake of June 1990 caused widespread damage to buildings in the city of Rasht located
60 km from the epicenter. Seismic surveys, including refraction P-wave, S-wave and downhole tests, were
carried out to study subsurface geology and classify materials in the city of Rasht. Rasht is built on Quaternary
sediments consisting of old marine (Q1m, deltaic (Q2d, undivided deltaic sediments with gravel (Qdg and
young marine (Q2m deposits. We used the variations of Vp in different materials to separate sedimentary
boundaries. The National Earthquake Hazard Reduction Program (NEHRP scheme was used for site classification.
Average S-wave velocity to a depth of 30 m was used to develop site categories, based on measured Vs values
in 35 refraction seismic profiles and 4 downhole tests. For each geological unit histograms of S-wave velocity
were calculated. This study reveals that the Vs(30 of most of the city falls into categories D and C of NEHRP
site classification. Average horizontal spectral amplification (AHSA in Rasht was calculated using Vs(30 . The
AHSA map clearly indicates that the amplification factor east and north of the city are higher than those of south
and central parts. The results show that the lateral changes and heterogeneities in Q1m sediments are significant
and most damaged buildings in 1990 Manjil earthquake were located in this unit.

Geological-genetic classification for uranium deposits

International Nuclear Information System (INIS)

Terentiev, V.M.; Naumov, S.S.

1997-01-01

The paper describes a system for classification uranium deposits based on geological and genetic characteristics. The system is based on the interrelation and interdependence of uranium ore formation processes and other geological phenomena including sedimentation, magmatism and tectonics, as well as the evolution of geotectonic structures. Using these aspects, deposits are classified in three categories: endogenic - predominately hydrothermal and hydrothermal-metasomatic; exogenic - sedimentary diagenetic, biogenic sorption, and infiltrational; and polygenetic or composite types. The latter complex types includes: sedimentary/metamorphic and metamorphic and sedimentary/hydrothermal, where different ore generating processes have prevailed over a rock unit at different times. The 3 page classification is given in both the English and Russian languages. (author). 3 tabs

OneGeology Web Services and Portal as a global geological SDI - latest standards and technology

Science.gov (United States)

Duffy, Tim; Tellez-Arenas, Agnes

2014-05-01

The global coverage of OneGeology Web Services (www.onegeology.org and portal.onegeology.org) achieved since 2007 from the 120 participating geological surveys will be reviewed and issues arising discussed. Recent enhancements to the OneGeology Web Services capabilities will be covered including new up to 5 star service accreditation scheme utilising the ISO/OGC Web Mapping Service standard version 1.3, core ISO 19115 metadata additions and Version 2.0 Web Feature Services (WFS) serving the new IUGS-CGI GeoSciML V3.2 geological web data exchange language standard (http://www.geosciml.org/) with its associated 30+ IUGS-CGI available vocabularies (http://resource.geosciml.org/ and http://srvgeosciml.brgm.fr/eXist2010/brgm/client.html). Use of the CGI simpelithology and timescale dictionaries now allow those who wish to do so to offer data harmonisation to query their GeoSciML 3.2 based Web Feature Services and their GeoSciML_Portrayal V2.0.1 (http://www.geosciml.org/) Web Map Services in the OneGeology portal (http://portal.onegeology.org). Contributing to OneGeology involves offering to serve ideally 1:1000,000 scale geological data (in practice any scale now is warmly welcomed) as an OGC (Open Geospatial Consortium) standard based WMS (Web Mapping Service) service from an available WWW server. This may either be hosted within the Geological Survey or a neighbouring, regional or elsewhere institution that offers to serve that data for them i.e. offers to help technically by providing the web serving IT infrastructure as a 'buddy'. OneGeology is a standards focussed Spatial Data Infrastructure (SDI) and works to ensure that these standards work together and it is now possible for European Geological Surveys to register their INSPIRE web services within the OneGeology SDI (e.g. see http://www.geosciml.org/geosciml/3.2/documentation/cookbook/INSPIRE_GeoSciML_Cookbook%20_1.0.pdf). The Onegeology portal (http://portal.onegeology.org) is the first port of call for anyone

Uruguayan South Geology

International Nuclear Information System (INIS)

Guillemain, H.

1980-01-01

This monograph is about the sedimentary geological formation in the southern of Uruguay. According to the previous Gondwana studies there are several concordances between the Uruguayan and Brazilian ground.

Geochemistry of sedimentary carbonates

National Research Council Canada - National Science Library

Morse, John W; Mackenzie, Fred T

1990-01-01

.... The last major section is two chapters on the global cycle of carbon and human intervention, and the role of sedimentary carbonates as indicators of stability and changes in Earth's surface environment...

Gravimetric survey and modeling of the basement morphology in the sedimentary thickness characterization, NE portion of Paraná Sedimentary Basin - Brazil

Directory of Open Access Journals (Sweden)

Maximilian Fries

2017-05-01

Full Text Available ABSTRACT: The northeast portion of the Paraná Sedimentary Basin is distinguished by structural highs as the known Pitanga Dome, an uplifted structure identified in the last century. It represents a geological and evolutionary evidence of the Paraná Sedimentary Basin and has undergone inspired studies and intense exploration surveys. This study consists of a gravimetric survey in the Pitanga Dome area, State of São Paulo, Brazil. The Bouguer gravity anomalies have been identified and related to the structural high, sedimentary thickness, and the basement morphology. Processing and enhancement techniques were used for forward modeling based on previous studies. The three models from profiles sectioning the dome have a sedimentary thickness varying from 200 to 1.250 meters. The adopted methodology has provided important results determining that the Pitanga Dome can be understood through rational 3D visualization. The area can be interpreted as an undulating basement with thinning of sedimentary rocks related to deep features (structures in the crust/mantle limit (Moho uplift. This characteristic is confirmed by the sedimentary layer thickening present throughout the surrounding area. The results also offer important insights and support for further studies concerning the genesis and evolution of this and other uplifted structures of the Paraná Sedimentary Basin.

Determining the Accuracy of Paleomagnetic Remanence and High-Resolution Chronostratigraphy for Sedimentary Rocks using Rock Magnetics

Science.gov (United States)

Kodama, K. P.

2017-12-01

The talk will consider two broad topics in rock magnetism and paleomagnetism: the accuracy of paleomagnetic remanence and the use of rock magnetics to measure geologic time in sedimentary sequences. The accuracy of the inclination recorded by sedimentary rocks is crucial to paleogeographic reconstructions. Laboratory compaction experiments show that inclination shallows on the order of 10˚-15˚. Corrections to the inclination can be made using the effects of compaction on the directional distribution of secular variation recorded by sediments or the anisotropy of the magnetic grains carrying the ancient remanence. A summary of all the compaction correction studies as of 2012 shows that 85% of sedimentary rocks studied have enjoyed some amount of inclination shallowing. Future work should also consider the effect of grain-scale strain on paleomagnetic remanence. High resolution chronostratigraphy can be assigned to a sedimentary sequence using rock magnetics to detect astronomically-forced climate cycles. The power of the technique is relatively quick, non-destructive measurements, the objective identification of the cycles compared to facies interpretations, and the sensitivity of rock magnetics to subtle changes in sedimentary source. An example of this technique comes from using rock magnetics to identify astronomically-forced climate cycles in three globally distributed occurrences of the Shuram carbon isotope excursion. The Shuram excursion may record the oxidation of the world ocean in the Ediacaran, just before the Cambrian explosion of metazoans. Using rock magnetic cyclostratigraphy, the excursion is shown to have the same duration (8-9 Myr) in southern California, south China and south Australia. Magnetostratigraphy of the rocks carrying the excursion in California and Australia shows a reversed to normal geomagnetic field polarity transition at the excursion's nadir, thus supporting the synchroneity of the excursion globally. Both results point to a

Study on flow and mass transport through fractured sedimentary rocks (2)

International Nuclear Information System (INIS)

Shimo, Michito; Kumamoto, Sou; Karasaki, Kenzi; Sato, Hisashi; Sawada, Atsushi

2009-03-01

It is important for safety assessment of HLW geological disposal to understand hydro-geological conditions at the investigation area, and to evaluate groundwater flow and mass transport model and parameters, at each investigation phase. Traditionally, for Neogene sedimentary rock, the grain spacing of sediments has been considered as the dominant migration path. However, fractures of sedimentary rock could act as dominant paths, although they were soft sedimentary rocks. In this study, as part of developing groundwater flow and mass transport evaluation methodologies of such a fractured sedimentary rock' distributed area, we conducted two different scale of studies; 1) core rock sample scale and 2) several kilometer scale. For the core rock sample scale, some of laboratory hydraulic and tracer experiments have conducted using the rock cores with tailored parallel fracture, obtained at pilot borehole drilled in the vicinity of ventilation shaft. From the test results, hydraulic conductivity, diffusion coefficient, transport aperture, dispersion length and etc. was evaluated. Based on these test results, the influence of these parameters onto mass transport behavior of fractures sedimentary rocks was examined. For larger scale, such as several kilometer scale, the regional scale groundwater flow was examined using temperature data observed along the boreholes at Horonobe site. The results show that the low permeable zone between the boreholes might be estimated. (author)

Sedimentary noise and sea levels linked to land-ocean water exchange and obliquity forcing.

Science.gov (United States)

Li, Mingsong; Hinnov, Linda A; Huang, Chunju; Ogg, James G

2018-03-08

In ancient hothouses lacking ice sheets, the origins of large, million-year (myr)-scale sea-level oscillations remain a mystery, challenging current models of sea-level change. To address this mystery, we develop a sedimentary noise model for sea-level changes that simultaneously estimates geologic time and sea level from astronomically forced marginal marine stratigraphy. The noise model involves two complementary approaches: dynamic noise after orbital tuning (DYNOT) and lag-1 autocorrelation coefficient (ρ 1 ). Noise modeling of Lower Triassic marine slope stratigraphy in South China reveal evidence for global sea-level variations in the Early Triassic hothouse that are anti-phased with continental water storage variations in the Germanic Basin. This supports the hypothesis that long-period (1-2 myr) astronomically forced water mass exchange between land and ocean reservoirs is a missing link for reconciling geological records and models for sea-level change during non-glacial periods.

The Punta del Este terrain and its volcano sedimentary cover, metamorphic and sedimentary: geology, geochemistry and geochronology

International Nuclear Information System (INIS)

Preciozzi, F.

2015-01-01

Gariep belt it develops over the West Africa coastal region of Namibia underlying on Namaqua metamorphic complex.It characterized by supra crustal rocks affected for a very low to low metamorphism and in two tecto no-stratigraphic units identified by Base i et al 2005 showing that sediments of Formation Rocha in Uruguay and the Group Oranjemund Gariep in S E Africa have similar ages in the provenance of the zircons, suggesting that they were probably deposited in the same basin. This unit exhibits detrital zircons around 600my, sedimentation and metamorphism and deformación occur in a narrow time interval from 600-610 to 574 m (Granite de Castillo intrusion) .Cam pal et al, 2005 proposed to the Cerros Aguirre Formation similar in a range of age of different events. To the east separated from the Punta del Este Terrane –Pelotas. Aigua .Florianopolis batholith s by the shear zone Alferez Cordillera (Preciozzi et al. 1999, Basei et al. 2000) Another option develops this granitic belt is an integral part of Land Punta del Este Terrane(Preciozzi in this work), being deployed on a thin cratonic granite edge. The climax of the post-brasilian magmatism is 580my, strongly related to trans current movements (eg shear zones Major Gercino-Alferez- Cordillera and Sierra Ballena.In South America an old west domain is formed by the Piedra Alta Terrane which integrate the Río de la Pl ata Craton, a central domain intensely reworked by Neoproterozoic events known so far as Nico Perez . The primary coverage is integrated by two volcano-sedimentary basins (San Carlos Formation and Cerros de Aguirre Formation)In this study are considered the Geology,Geochemistry and Geochronology of the different units of Rocha Formation

The geological carbon cycle and the global warming / climate debate

International Nuclear Information System (INIS)

Frank, F.

2013-01-01

The extensively cited seasonal carbon cycle describes the size and the annual fluxes between the temporary reservoirs (ocean, atmosphere, biosphere and soils). Compared with these large annual fluxes (approx. 200 GtC/y) the human contribution seems to be of minor amount and is currently (2011) in the range of 4-5%. However, in the geological carbon cycle, which describes the nearly equal amounts of input (volcanoes etc.) and output (sediments) into and from the temporary reservoirs, the human contribution has now reached 30-50 times the average natural level (9.5 Gt C/y versus ca. 0.2-0.3Gt C/y). In the long-term range (1-10x106y), the variable, but much smaller net imbalance between these geological sources und sinks was responsible for the atmospheric CO2-level in the last 400 My (since then comparable temporary reservoirs exist) and influenced via the various feedbacks the climate on earth. In nearly 95% of this long time the climate system was in (nearly) equilibrium conditions and changes occurred extremely slow. Whenever a certain range of higher rate of change of these driving forces were reached, it had - together with other effects - severe influence on the evolution of life, causing 5 large and many minor 'geological accidents'. Based on isotope geochemistry and a fairly good time resolution by orbitally tuned cyclostratigraphy (astrochronology) in the sedimentary record, we are able to quantify these rates of change with reasonable errors. It turns out that the present rate of change - caused by the C-based fossil energy use - is one to two orders of magnitude more rapid than these severe events (impacts excluded) in the earth system. A vast amount of data is available from the ice age cycles. Climate geology (e.g. the group of M. Sarnthein) made considerable progress in understanding the related geological/oceanic processes and proposed a reasonably constrained mass balance of CO2 during the last cycle, which could help us to understand the future

Engineering Geological Properties of Oil-Contaminated Granitic and Meta sedimentary Soils

International Nuclear Information System (INIS)

Zulfahmi Ali Rahman; Umar Hamzah; Noorulakma Ahmad

2011-01-01

Hydrocarbon is a light-non aqueous phase liquid or known as LNAPL. It poses environmental hazard if accidentally spilled out into the soil and water systems as a result of its insoluble nature in water. LNAPL component infiltrates into soil through pore spaces and afloat at the top of groundwater level. Some of this hydrocarbon would trap and clog within the voids, difficult to remove and costly to clean. The occurrence of hydrocarbon in the soil definitely degraded the behaviour of soils in terms of engineering properties. This study aimed to investigate the engineering properties of oil-contaminated soil for two different residual soils originally developed from in-situ weathering of granitic and meta sedimentary rocks. The physical characterisations of the soil were determined including particle size distribution, specific gravity test and x-ray diffraction (XRD). The engineering parameters for the contaminated and uncontaminated soils were Atterberg limits, compaction and soil shear strength (UU tests). The amounts of hydrocarbon added to soil were varied at 0 %, 4 %, 8 %, 12 % and 16 % of dried weight of soil samples. The results from the particle size distribution analysis showed that residual soil from granitic rock comprises of 38 % sand, 33 % silt and 4 % clay while meta sedimentary soil consists of 4 % sand, 43 % silt dan 29 % clay. The mean values of specific gravity for the granitic and meta sedimentary soils were 2.56 and 2.61, respectively. The types of minerals present in granitic soil sample were quartz, kaolinite and gibbsite while meta sedimentary soil consists of quartz and kaolinite. The Atterberg limits value decreased as a result of increasing amount of added hydrocarbon into the soil. A similar behavior was observed with the values of maximum dry density and optimum water content with increasing hydrocarbon content. The overall unconsolidated undrained shear strength, C u showed a decreasing trend with the increase in hydrocarbon content

Testing Urey's carbonate-silicate cycle using the calcium isotopic composition of sedimentary carbonates

Science.gov (United States)

Blättler, Clara L.; Higgins, John A.

2017-12-01

Carbonate minerals constitute a major component of the sedimentary geological record and an archive of a fraction of the carbon and calcium cycled through the Earth's surface reservoirs for over three billion years. For calcium, carbonate minerals constitute the ultimate sink for almost all calcium liberated during continental and submarine weathering of silicate minerals. This study presents >500 stable isotope ratios of calcium in Precambrian carbonate sediments, both limestones and dolomites, in an attempt to characterize the isotope mass balance of the sedimentary carbonate reservoir through time. The mean of the dataset is indistinguishable from estimates of the calcium isotope ratio of bulk silicate Earth, consistent with the Urey cycle being the dominant mechanism exchanging calcium among surface reservoirs. The variability in bulk sediment calcium isotope ratios within each geological unit does not reflect changes in the global calcium cycle, but rather highlights the importance of local mineralogical and/or diagenetic effects in the carbonate record. This dataset demonstrates the potential for calcium isotope ratios to help assess these local effects, such as the former presence of aragonite, even in rocks with a history of neomorphism and recrystallization. Additionally, 29 calcium isotope measurements are presented from ODP (Ocean Drilling Program) Site 801 that contribute to the characterization of altered oceanic crust as an additional sink for calcium, and whose distinct isotopic signature places a limit on the importance of this subduction flux over Earth history.

Sea-floor morphology and sedimentary environments in western Block Island Sound, offshore of Fishers Island, New York

Science.gov (United States)

McMullen, Katherine Y.; Poppe, Lawrence J.; Danforth, William W.; Blackwood, Dann S.; Winner, William G.; Parker, Castle E.

2015-01-01

Multibeam-bathymetric and sidescan-sonar data, collected by the National Oceanic and Atmospheric Administration in a 114-square-kilometer area of Block Island Sound, southeast of Fishers Island, New York, are combined with sediment samples and bottom photography collected by the U.S. Geological Survey from 36 stations in this area in order to interpret sea-floor features and sedimentary environments. These interpretations and datasets provide base maps for studies on benthic ecology and resource management. The geologic features and sedimentary environments on the sea floor are products of the area’s glacial history and modern processes. These features include bedrock, drumlins, boulders, cobbles, large current-scoured bathymetric depressions, obstacle marks, and glaciolacustrine sediments found in high-energy sedimentary environments of erosion or nondeposition; and sand waves and megaripples in sedimentary environments characterized by coarse-grained bedload transport. Trawl marks are preserved in lower energy environments of sorting and reworking. This report releases the multibeam-bathymetric, sidescan-sonar, sediment, and photographic data and interpretations of the features and sedimentary environments in Block Island Sound, offshore Fishers Island.

Vietnamese sedimentary basins: geological evolution and petroleum potential

Energy Technology Data Exchange (ETDEWEB)

Fyhn, M.B.W.; Petersen, Henrik I.; Mathiesen, A.; Nielsen, Lars H.; Pedersen, Stig A.S.; Lindstroem, S.; Bojesen-Koefoed, J.A.; Abatzis, I.; Boldreel, L.O.

2010-07-15

The Geological Survey of Denmark and Greenland has worked in Vietnam since 1995 to assess the geology and petroleum potential of the Vietnamese basins. Since 2002 the work has been carried out in cooperation with the Department of Geography and Geology, University of Copenhagen, as part of the ENRECA project (Enhancement of Research Capacity in Developing Countries). The ENRECA project has already completed two phases and a third and final phase has recently started. The initial phase focused on the Phu Khanh and the Song Hong Basins located in the South China Sea offshore north and central Vietnam and the smaller onshore Song Ba Trough. During the second ENRECA phase, completed in 2009, attention shifted towards the Malay - Tho Chu and Phu Quoc basins located in the Gulf of Thailand, SSW of Vietnam. The Phu Quoc Basin continues onshore to the north to form part of the mountainous area between Vietnam and Cambodia. In the recently started third phase of the project, the focus remains on the Phu Quoc Basin in addition to a revisit to the Song Hong Basin on the north Vietnamese margin and onshore beneath the Song Hong (Red River) delta. (LN)

Study on geology and geological structure based on literature studies

International Nuclear Information System (INIS)

Funaki, Hironori; Ishii, Eiichi; Yasue, Ken-ichi; Takahashi, Kazuharu

2005-03-01

Japan Nuclear Cycle Development Institute (JNC) is proceeding with underground research laboratory (URL) project for the sedimentary rock in Horonobe, Hokkaido. This project is an investigation project which is planned over 20 years. Surface-based investigations (Phase 1) have been conducted for the present. The purposes of the Phase 1 are to construct the geological environment model (geological-structural, hydrogeological, and hydrochemical models) and to confirm the applicability of investigation technologies for the geological environment. The geological-structural model comprises the base for the hydrogeological and hydrochemical models. We constructed the geological-structural model by mainly using data obtained from literature studies. Particulars regarding which data the model is based on and who has performed the interpretation are also saved for traceability. As a result, we explain the understanding of degree and the need of information on stratigraphy and discontinuous structure. (author)

Mapping Neogene and Quaternary sedimentary deposits in northeastern Brazil by integrating geophysics, remote sensing and geological field data

Science.gov (United States)

Andrades-Filho, Clódis de Oliveira; Rossetti, Dilce de Fátima; Bezerra, Francisco Hilario Rego; Medeiros, Walter Eugênio; Valeriano, Márcio de Morisson; Cremon, Édipo Henrique; Oliveira, Roberto Gusmão de

2014-12-01

Neogene and late Quaternary sedimentary deposits corresponding respectively to the Barreiras Formation and Post-Barreiras Sediments are abundant along the Brazilian coast. Such deposits are valuable for reconstructing sea level fluctuations and recording tectonic reactivation along the passive margin of South America. Despite this relevance, much effort remains to be invested in discriminating these units in their various areas of occurrence. The main objective of this work is to develop and test a new methodology for semi-automated mapping of Neogene and late Quaternary sedimentary deposits in northeastern Brazil integrating geophysical and remote sensing data. The central onshore Paraíba Basin was selected due to the recent availability of a detailed map based on the integration of surface and subsurface geological data. We used airborne gamma-ray spectrometry (i.e., potassium-K and thorium-Th concentration) and morphometric data (i.e., relief-dissection, slope and elevation) extracted from the digital elevation model (DEM) generated by the Shuttle Radar Topography Mission (SRTM). The procedures included: (a) data integration using geographic information systems (GIS); (b) exploratory statistical analyses, including the definition of parameters and thresholds for class discrimination for a set of sample plots; and (c) development and application of a decision-tree classification. Data validation was based on: (i) statistical analysis of geochemical and airborne gamma-ray spectrometry data consisting of K and Th concentrations; and (ii) map validation with the support of a confusion matrix, overall accuracy, as well as quantity disagreement and allocation disagreement for accuracy assessment based on field points. The concentration of K successfully separated the sedimentary units of the basin from Precambrian basement rocks. The relief-dissection morphometric variable allowed the discrimination between the Barreiras Formation and the Post-Barreiras Sediments. In

An Overview of the Soutpansberg Sedimentary and Volcanic Rocks

Directory of Open Access Journals (Sweden)

J.W. Bristow

1986-11-01

Full Text Available Volcanic and sedimentary rocks occupy a faulted graben within the previously uplifted and eroded high-grade gneiss terrain of the Limpopo Mobile Belt. The rocks comprise the Soutpansberg Group and represent an important sequence of Proterozoic rocks. Their general geology and volcanology is summarised in this paper.

The geological and microbiological controls on the enrichment of Se and Te in sedimentary rocks

Science.gov (United States)

Bullock, Liam; Parnell, John; Armstrong, Joseph; Boyce, Adrian; Perez, Magali

2017-04-01

Selenium (Se) and tellurium (Te) have become elements of high interest, mainly due to their photovoltaic and photoconductive properties, and can contaminate local soils and groundwater systems during mobilisation. Due to their economic and environmental significance, it is important to understand the processes that lead to Se- and Te-enrichment in sediments. The distribution of Se and Te in sedimentary environments is primarily a function of redox conditions, and may be transported and concentrated by the movement of reduced fluids through oxidised strata. Se and Te concentrations have been measured in a suite of late Neoproterozoic Gwna Group black shales (UK) and uranium red bed (roll-front) samples (USA). Due to the chemical affinity of Se and sulphur (S), variations in the S isotopic composition of pyrite have also been measured in order to provide insights into their origin. Scanning electron microscopy of pyrite in the black shales shows abundant inclusions of the lead selenide mineral clausthalite. The data for the black shale samples show marked enrichment in Te and Se relative to crustal mean and several hundreds of other samples processed through our laboratory. While Se levels in sulphidic black shales are typically below 5 ppm, the measured values of up to 116 ppm are remarkable. The Se enrichment in roll-fronts (up to 168 ppm) is restricted to a narrow band of alteration at the interface between the barren oxidised core, and the highly mineralised reduced nose of the front. Te is depleted in roll-fronts with respect to the continental crust and other geological settings and deposits. S isotope compositions for pyrite in both the black shales and roll-fronts are very light and indicate precipitation by microbial sulphate reduction, suggesting that Se was microbially sequestered. Results show that Gwna Group black shales and U.S roll-front deposits contain marked elemental enrichments (particularly Se content). In Gwna Group black shales, Se and Te were

A Framework to Estimate CO2 Leakage associated with Geological Storage in Mature Sedimentary Basins

Science.gov (United States)

Celia, M. A.; Bachu, S.; Gasda, S.

2002-12-01

Geological storage of carbon dioxide requires careful risk analysis to avoid unintended consequences associated with the subsurface injection. Most negative consequences of subsurface injection are associated with leakage of the injected CO2 out of the geological formation into which it is injected. Such leakage may occur through natural geological features, including fractures and faults, or it may occur through human-created pathways such as existing wells. Possible leakage of CO2 through existing wells appears to be especially important in mature sedimentary basins that have been explored intensively and exploited for hydrocarbon production. In the Alberta Basin of western Canada, more than 300,000 oil and gas wells have been drilled, while in the state of Texas in the United States, more than 1,500,000 wells have been drilled. Many of these wells have been abandoned, and the information available to describe their current state is highly variable and sometimes nonexistent. Because these wells represent possible direct conduits from the injection zone to the land surface, a comprehensive assessment of leakage potential associated with these wells needs to be pursued. Analysis of leakage potential associated with existing wells must combine a data mining component with a multi-level modeling effort to assess leakage potential in a probabilistic framework. Information available for existing wells must be categorized and analyzed, and general leakage characteristics associated with wells of varying properties must be quantified. One example of a realistic target formation is the Viking Formation in Alberta, which is overlain by a thick shale layer and contains hydrocarbon in some locations. The existence of hydrocarbon in the formation indicates that the overlying shale layer is an effective barrier to flow, and therefore this is a good candidate formation for CO2 storage. However, the formation and its cap rock are punctured by approximately 180,000 wells, with

Geologic mapping of the Amirani-Gish Bar region of Io: Implications for the global geologic mapping of Io

Science.gov (United States)

Williams, D.A.; Keszthelyi, L.P.; Crown, D.A.; Jaeger, W.L.; Schenk, P.M.

2007-01-01

We produced the first geologic map of the Amirani-Gish Bar region of Io, the last of four regional maps generated from Galileo mission data. The Amirani-Gish Bar region has five primary types of geologic materials: plains, mountains, patera floors, flows, and diffuse deposits. The flows and patera floors are thought to be compositionally similar, but are subdivided based on interpretations regarding their emplacement environments and mechanisms. Our mapping shows that volcanic activity in the Amirani-Gish Bar region is dominated by the Amirani Eruptive Center (AEC), now recognized to be part of an extensive, combined Amirani-Maui flow field. A mappable flow connects Amirani and Maui, suggesting that Maui is fed from Amirani, such that the post-Voyager designation "Maui Eruptive Center" should be revised. Amirani contains at least four hot spots detected by Galileo, and is the source of widespread bright (sulfur?) flows and active dark (silicate?) flows being emplaced in the Promethean style (slowly emplaced, compound flow fields). The floor of Gish Bar Patera has been partially resurfaced by dark lava flows, although other parts of its floor are bright and appeared unchanged during the Galileo mission. This suggests that the floor did not undergo complete resurfacing as a lava lake as proposed for other ionian paterae. There are several other hot spots in the region that are the sources of both active dark flows (confined within paterae), and SO2- and S2-rich diffuse deposits. Mapped diffuse deposits around fractures on mountains and in the plains appear to serve as the source for gas venting without the release of magma, an association previously unrecognized in this region. The six mountains mapped in this region exhibit various states of degradation. In addition to gaining insight into this region of Io, all four maps are studied to assess the best methodology to use to produce a new global geologic map of Io based on the newly released, combined Galileo

In-situ heating test in sedimentary soft rock. Phase 2

International Nuclear Information System (INIS)

Ikenoya, Takafumi; Takakura, Nozomu; Okada, Tetsuji; Sawada, Masataka; Hirano, Kouhei; Tani, Kazuo

2011-01-01

Various researches have been conducted on high level radioactive waste geological disposal in sedimentary soft rocks. It is noted that the long-term mechanical behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperatures or hydraulic conditions. Therefore, in-situ heater test was conducted in an underground cavern at a depth of 50 m for the purpose of improving thermo-hydro-mechanical coupled analysis code. This report presents the test result demonstrating the changes of temperature and strain distributions with time at the elevated temperature of the heater up to 90degC. (author)

Differential preservation in the geologic record of intraoceanic arc sedimentary and tectonic processes

Science.gov (United States)

Draut, Amy; Clift, Peter D.

2013-01-01

Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are commonly used to reconstruct paleogeography and plate motion, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records from ancient terranes after arc–continent collision is complicated by preferential preservation of evidence for some arc processes and loss of evidence for others. In this synthesis we examine what is lost, and what is preserved, in the translation from modern processes to the ancient record of intraoceanic arcs. Composition of accreted arc terranes differs as a function of arc–continent collision geometry. ‘Forward-facing’ collision can accrete an oceanic arc on to either a passive or an active continental margin, with the arc facing the continent and colliding trench- and forearc-side first. In a ‘backward-facing’ collision, involving two subduction zones with similar polarity, the arc collides backarc-first with an active continental margin. The preservation of evidence for contemporary sedimentary and tectonic arc processes in the geologic record depends greatly on how well the various parts of the arc survive collision and orogeny in each case. Preservation of arc terranes likely is biased towards those that were in a state of tectonic accretion for tens of millions of years before collision, rather than tectonic erosion. The prevalence of tectonic erosion in modern intraoceanic arcs implies that valuable records of arc processes are commonly destroyed even before the arc collides with a continent. Arc systems are most likely to undergo tectonic accretion shortly before forward-facing collision with a continent, and thus most forearc and accretionary-prism material in ancient arc terranes likely is temporally biased toward the final stages of arc activity, when sediment flux to the trench was greatest and tectonic accretion prevailed. Collision geometry

Sedimentary environment and facies of St Lucia Estuary Mouth, Zululand, South Africa

Science.gov (United States)

Wright, C. I.; Mason, T. R.

The St. Lucia Estuary is situated on the subtropical, predominantly microtidal Zululand coast. Modern sedimentary environments within the estuary fall into three categories: (1) barrier environments; (2) abandoned channel environments; and (3) estuarine/lagoonal environments. The barrier-associated environment includes tidal inlet channel, inlet beach face, flood-tidal delta, ebb-tidal delta, spit, backspit and aeolian dune facies. The abandoned channel environment comprises washover fan, tidal creek tidal creek delta and back-barrier lagoon facies. The estuarine/lagoonal environment includes subtidal estuarine channel, side-attached bar, channel margin, mangrove fringe and channel island facies. Each sedimentary facies is characterised by sedimentary and biogenic structures, grain-size and sedimentary processes. Vertical facies sequences produced by inlet channel migration and lagoonal infilling are sufficiently distinct to be recognized in the geological record and are typical of a prograding shoreline.

CSPG - SEPM joint convention : Program with abstracts - Sedimentary events and hydrocarbon systems

International Nuclear Information System (INIS)

Beauchamp, B.

1997-01-01

This joint conference of the Canadian Society of Petroleum Geologists (CSPG) and the Society for Sedimentary Geology (SEPM) was held in Calgary, to encourage collaboration between the petroleum resource industry and academia. Well over 150 papers were presented in various special sessions. The principal topics of discussion included examination, investigation and assessment of the geology, geophysics, geochemistry and the resource potential of sedimentary basins in Canada and around the world. In the course of the presentations the depositional, tectonic and diagenetic histories of various formations, augmented with interpretations of the origin and evolution of the basins were reviewed. The new interpretations were made possible by the new concepts and models of sedimentary geoscience that were born in the creative cauldron of collaboration that exists between industry, government institutions and the universities. The widespread use of modern sequence stratigraphy was used as an example of how scientific and engineering synergy evolved over time to shed new light on the nature of the stratigraphic record. Environmental issues regarding the petroleum industry also received much attention. This volume contains the complete conference program listing, a list of the sponsors and exhibitors, and provides brief abstracts of all papers presented at the conference

Proceedings of the 7. Symposium on geology from southeastern Brazil

International Nuclear Information System (INIS)

2001-01-01

This document presents papers on the following subjects: regional geology of the proterozoic and fanerozoic, metallic and non metallic resources, tectoni-sedimentary evolution of the eastern margin Brazil basins and petroleum geology applied to the Santos, Campos and Espirito Santo basins, engineering and environmental geologies, ornamental rocks/building materials/mineral waters/industrial ores

Geological heritage diversity in the Faiyum Oasis (Egypt): A comprehensive assessment

Science.gov (United States)

Sallam, Emad S.; Fathy, Esraa E.; Ruban, Dmitry A.; Ponedelnik, Alena A.; Yashalova, Natalia N.

2018-04-01

The Faiyum Oasis in the Western Desert of Egypt is famous for its palaeontological localities (Cenozoic whales, primates, etc.) of global importance, but its geological heritage has been not studied in the modern theoretical frame. The new investigation based on the field studies and the literature review permits comprehensive assessment of the geological heritage diversity in this oasis. For this purposes, unique geological features are inventoried with establishment of their geological essence, rank, relative abundance, and intrinsic diversity. As a result, the existence of ten geological heritage types in the Faiyum Oasis is found. These include palaeontological, palaeogeographical, geomorphological, stratigraphical, sedimentary (merged with mineralogical), hydrological coupled with geochemical, igneous, and economical types. From them, the palaeontological and palaeogeographical types are ranked globally, and the geomorphological and hydrological types are ranked nationally. The other types are either of regional (provincial) or local importance. Some hills and cliffs can serve as viewpoint sites for observation of the local geological landscape. The relative abundance and the intrinsic diversity of the unique geological features vary between low and high. Generally, the concentration of this geological heritage in the Faiyum Oasis permits recognition of the geodiversity hotspot that requires conservation and use for tourism purposes. The protected areas located in the oasis and the existing tourism programs do not offer geoconservation and geotourism activities for the entire hotspot. The possible solution of this problem would be creation of a large geopark similar in its design to the Jeju Island Geopark in South Korea. There are important premises for geotourism development in the Faiyum Oasis and its combination with the archaeological and industrial tourism. Nature conservation failures in this geopark should be avoided; some recommendations are given on

DOE workshop: Sedimentary systems, aqueous and organic geochemistry

International Nuclear Information System (INIS)

1993-07-01

A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries

DOE workshop: Sedimentary systems, aqueous and organic geochemistry

Energy Technology Data Exchange (ETDEWEB)

1993-07-01

A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries.

The Oligocene carbonate platform of the Zagros Basin, SW Iran: An assessment of highly-complex geological heritage

Science.gov (United States)

Habibi, Tahereh; Ruban, Dmitry A.

2017-05-01

North Africa and the Middle East possess rich geological heritage, but the latter is yet to be fully identified and described. The Oligocene carbonate platform of the Zagros Basin in southwest Iran, which corresponds to the lower part of the Asmari Formation, has significant potential for geoconservation and geotourism. The types of the geological heritage, their value, and the possible geosites have been assessed. The studied deposits are interesting because of lithology (carbonate rocks), fossils (larger foraminifera, other microfossils, diverse marine invertebrates, fish microremains, and trace fossils), biostratigraphical developments, facies (homoclinal carbonate ramp) and signature of global events (glacioeustatic fluctuations), and outstanding hydrocarbon resources. The five main geological heritage types are sedimentary, palaeontological, stratigraphical, palaeogeographical, and economical, from which the palaeontological, palaeogeographical, and economical types are of global rank. The Khollar and Kavar sections in the Fars Province of Iran are recommended as geosites suitable for research, education, and tourism. The high complexity of the geological heritage linked to the Oligocene carbonate platform of the Zagros Basin implies the phenomenon of geodiversity should be understood with regard to the relationships between types and their values.

Determination of Cenozoic sedimentary structures using integrated geophysical surveys: A case study in the Barkol Basin, Xinjiang, China

Science.gov (United States)

Sun, Kai; Chen, Chao; Du, Jinsong; Wang, Limin; Lei, Binhua

2018-01-01

Thickness estimation of sedimentary basin is a complex geological problem, especially in an orogenic environment. Intense and multiple tectonic movements and climate changes result in inhomogeneity of sedimentary layers and basement configurations, which making sedimentary structure modelling difficult. In this study, integrated geophysical methods, including gravity, magnetotelluric (MT) sounding and electrical resistivity tomography (ERT), were used to estimate basement relief to understand the geological structure and evolution of the eastern Barkol Basin in China. This basin formed with the uplift of the eastern Tianshan during the Cenozoic. Gravity anomaly map revealed the framework of the entire area, and ERT as well as MT sections reflected the geoelectric features of the Cenozoic two-layer distribution. Therefore, gravity data, constrained by MT, ERT and boreholes, were utilized to estimate the spatial distribution of the Quaternary layer. The gravity effect of the Quaternary layer related to the Tertiary layer was later subtracted to obtain the residual anomaly for inversion. For the Tertiary layer, the study area was divided into several parts because of lateral difference of density contrasts. Gravity data were interpreted to determine the density contrast constrained by the MT results. The basement relief can be verified by geological investigation, including the uplift process and regional tectonic setting. The agreement between geophysical survey and prior information from geology emphasizes the importance of integrated geophysical survey as a complementary means of geological studies in this region.

Sedimentary mode and reservoir distribution of the Cambrian carbonate & evaporate paragenesis system in the Sichuan Basin

Directory of Open Access Journals (Sweden)

Anna Xu

2016-11-01

Full Text Available The Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin is made up of the Longwangmiao, Gaotai and Xixiangchi Fms. So far, great breakthrough has been made only in the Longwangmiao Fm instead of the latter two, and the Anyue Gasfield was discovered in the center of this basin. In this paper, therefore, the Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin was analyzed in terms of its structural–sedimentary setting, sequence stratigraphic framework, sedimentary facies and the distribution of evaporites by using various geologic, logging and seismic data. Then, the geological model of sedimentary facies was established and the distribution range of favorable reservoirs was predicted. Based on these studies, the following results are obtained. Firstly, the palaeotectonic framework is characterized by the style of “one depression between two uplifts” in the setting of a large SE dipping slope, and the stratigraphic filling is in the structure of “onlapping at the bottom and truncation at the top” which is thin in the west and thick in the east. Secondly, three third-order sequence cycles which, on the whole, become shallow upward are developed from bottom to top, and gypsum-salt rocks are mainly located at the high system tract (HST of third-order sequences and concentrated in the Wanzhou–Yibin sag. Thirdly, the geological model of sedimentary facies is composed of three major sedimentary structural layers from bottom to top, namely the evaporative carbonate ramp, the evaporative diamictic restricted platform and the evaporative restricted platform. The sedimentary environment changes from the open to the closed and the penesaline for a long time, and then back to the open. The distribution of shoals changes from the pattern of “dual banks” in a large area to more scattered shoals and banded shoals, while the evaporative lagoon and tidal flat shrink. Fourthly, the reservoir distribution is

Geological evolution of clay sediments: the petroleum exploration vision

International Nuclear Information System (INIS)

Schneider, F.

2004-01-01

The radioactive waste isolation capacity assessment for a clay sediment host rock is link: (1) to the understanding of their present state properties and 3-D repartition (from basin evolution, including sedimentary and diagenetic process); and (2) to the prediction of their future evolution during the next million years. For petroleum exploration, basin modelling aims at reconstructing the accumulation of hydrocarbons at basin scale, and at geological timescale, taking into account the effects of kinematics displacements, sedimentation, erosion, compaction, temperatures history, overpressures and fluids flows (water and hydrocarbons). Furthermore, explorationists wish to address overpressure reconstruction in order to estimate the risks of drilling. Clay sediments are of interest for petroleum exploration because source rocks and seal are generally composed of them. Nevertheless, in spite of their occurrence in nature their evolution at geological timescale is not well understood. And, most of the knowledge has been achieved by those working in the realms of soils mechanics and civil engineering until the present geological investigations for long term radioactive waste repositories. Application of this knowledge to clay sediment is considered to be valid within the first hundreds of meters at the top of the sedimentary pile, according to a repository depth. This paper is dedicated to the sedimentary rocks behaviour at geological timescale. This behaviour is characterised by: (1) the deposition of the sediment; (2) the loading path at geological timescale; (3) the constitutive law which includes the consolidation process and the rupture criteria; and (4) the parameters evolution related to consolidation. (author)

Explorability and predictability of the paleozoic sedimentary sequence beneath the Bruce nuclear site

International Nuclear Information System (INIS)

Parmenter, A.; Jensen, M.; Crowe, R.; Raven, K.

2011-01-01

Ontario Power Generation (OPG) is proposing to develop a Deep Geologic Repository (DGR) for the long-term management of its Low and Intermediate Level Waste (L&ILW) at the Bruce nuclear site located in the Municipality of Kincardine, Ontario. A 4-year program of geoscientific studies to assess the suitability of the 850 m thick Palaeozoic age sedimentary sequence beneath the site to host the DGR was completed in 2010. The studies provide evidence of a geologic setting in which the DGR concept would be safely implemented at a nominal depth of 680 m within the argillaceous limestone of the Cobourg Formation. This paper describes the geologic framework of the Bruce nuclear site with a focus on illustrating the high degree of stratigraphic continuity and traceability at site-specific and regional scales within the Ordovician sediments proposed to host and enclose the DGR. As part of the site-specific studies, a program of deep drilling/coring (6 boreholes) and in-situ testing through the sedimentary sequence was completed from 4 drill sites situated beyond the DGR footprint, approximately 1 km apart. Core logging reveals that the stratigraphic sequence comprises 34 distinct bedrock formations/members/units consistent with the known regional stratigraphic framework. These layered sedimentary formations dip 0.6 o (~10 m/km) to the southwest with highly uniform thicknesses both at the site- and regional-scale, particularly, the Ordovician sediments, which vary on the order of metres. The occurrence of steeply-dipping faults within the sedimentary sequence is not revealed through surface outcrop fracture mapping, micro-seismic (M ≥ 1) monitoring, inclined borehole coring or intersection of hydrothermal type dolomitized reservoir systems. Potential fault structures, interpreted from a 2-D seismic survey, were targeted by angled boreholes which found no evidence for their existence. Formation specific continuity is also evidence by the lateral traceability of physical rock

Geological Corrections in Gravimetry

Science.gov (United States)

Mikuška, J.; Marušiak, I.

2015-12-01

Applying corrections for the known geology to gravity data can be traced back into the first quarter of the 20th century. Later on, mostly in areas with sedimentary cover, at local and regional scales, the correction known as gravity stripping has been in use since the mid 1960s, provided that there was enough geological information. Stripping at regional to global scales became possible after releasing the CRUST 2.0 and later CRUST 1.0 models in the years 2000 and 2013, respectively. Especially the later model provides quite a new view on the relevant geometries and on the topographic and crustal densities as well as on the crust/mantle density contrast. Thus, the isostatic corrections, which have been often used in the past, can now be replaced by procedures working with an independent information interpreted primarily from seismic studies. We have developed software for performing geological corrections in space domain, based on a-priori geometry and density grids which can be of either rectangular or spherical/ellipsoidal types with cells of the shapes of rectangles, tesseroids or triangles. It enables us to calculate the required gravitational effects not only in the form of surface maps or profiles but, for instance, also along vertical lines, which can shed some additional light on the nature of the geological correction. The software can work at a variety of scales and considers the input information to an optional distance from the calculation point up to the antipodes. Our main objective is to treat geological correction as an alternative to accounting for the topography with varying densities since the bottoms of the topographic masses, namely the geoid or ellipsoid, generally do not represent geological boundaries. As well we would like to call attention to the possible distortions of the corrected gravity anomalies. This work was supported by the Slovak Research and Development Agency under the contract APVV-0827-12.

Comparative geology and geochemistry of sedimentary-rock-hosted (Carlin Type) gold deposits in the People's Republic of China and in Nevada, USA

Science.gov (United States)

Li, Zhiping; Peters, Stephen G.

1998-01-01

Sedimentary-rock-hosted (Carlin-type) gold deposits have been considered economically significant and geologically distinct since the early 1960's. This report consists of a nine-part text and an interactive database. This small database is to help Western companies get more information about these gold deposits in China, and to help geologists who are interested in world Carlin-type deposits conduct research on them. Because of their economic significance and geological distinctiveness, these deposits have caught the interest of economic geologists all over the world since the early 1960's. Similar deposits have been discovered in China, Australia, Dominican Republic, Spain, and Russia besides Nevada. Perhaps most significant are the 165 Carlin-type gold deposits that were found in southwest China during the past 15 years. Of these, at least 19 deposits have proven to be of substantial tonnage, making China the second leading country to exploit such deposits. With the increasing interest in Chinese Carlin-type gold deposits, some western companies and geologists desire to get more information about these Chinese deposits. This seems to have been very difficult because the literature was in Chinese. It is estimated that several hundred scientific publications (including papers, books, and technical reports) have been published. This database of Chinese Carlin-type Gold deposits is built on the documentation published during the most recent 10 years and includes six subjects, which consist of 165 records and 30 fields. A new Proterozoic-age sedimentary-rock-hosted gold deposit in northeastern P.R. China also is described. Note that for the old version 1.1 on the CD-ROM, the latitude and longitude locations of the mineral occurrences have been estimated from sketch maps and journal articles and are not intended for digital analysis. One of the improvements in this version 1.2 is the accuracy of geographic data. Version 1.3 updates to the database and includes maps

Compaction and sedimentary basin analysis on Mars

Science.gov (United States)

Gabasova, Leila R.; Kite, Edwin S.

2018-03-01

Many of the sedimentary basins of Mars show patterns of faults and off-horizontal layers that, if correctly understood, could serve as a key to basin history. Sediment compaction is a possible cause of these patterns. We quantified the possible role of differential sediment compaction for two Martian sedimentary basins: the sediment fill of Gunjur crater (which shows concentric graben), and the sediment fill of Gale crater (which shows outward-dipping layers). We assume that basement topography for these craters is similar to the present-day topography of complex craters that lack sediment infill. For Gunjur, we find that differential compaction produces maximum strains consistent with the locations of observed graben. For Gale, we were able to approximately reproduce the observed layer orientations measured from orbiter image-based digital terrain models, but only with a >3 km-thick donut-shaped past overburden. It is not immediately obvious what geologic processes could produce this shape.

Material Units, Structures/Landforms, and Stratigraphy for the Global Geologic Map of Ganymede (1:15M)

Science.gov (United States)

Patterson, G. Wesley; Head, James W.; Collins, Geoffrey C.; Pappalardo, Robert T.; Prockter, Louis M.; Lucchitta, Baerbel K.

2008-01-01

In the coming year a global geological map of Ganymede will be completed that represents the most recent understanding of the satellite on the basis of Galileo mission results. This contribution builds on important previous accomplishments in the study of Ganymede utilizing Voyager data and incorporates the many new discoveries that were brought about by examination of Galileo data. Material units have been defined, structural landforms have been identified, and an approximate stratigraphy has been determined utilizing a global mosaic of the surface with a nominal resolution of 1 km/pixel assembled by the USGS. This mosaic incorporates the best available Voyager and Galileo regional coverage and high resolution imagery (100-200 m/pixel) of characteristic features and terrain types obtained by the Galileo spacecraft. This map has given us a more complete understanding of: 1) the major geological processes operating on Ganymede, 2) the characteristics of the geological units making up its surface, 3) the stratigraphic relationships of geological units and structures, and 4) the geological history inferred from these relationships. A summary of these efforts is provided here.

Derivation of Strike and Dip in Sedimentary Terrain Using 3D Image Interpretation Based on Airborne LiDAR Data

Directory of Open Access Journals (Sweden)

Chih-Hsiang Yeh

2014-01-01

Full Text Available Traditional geological mapping may be hindered by rough terrain and dense vegetation resulting in obscured geological details. The advent of airborne Light Detection and Ranging (LiDAR provides a very precise three-dimensional (3D digital terrain model (DTM. However, its full potential in complementing traditional geological mapping remains to be explored using 3D rendering techniques. This study uses two types of 3D images which differ in imaging principles to further explore the finer details of sedimentary terrain. Our purposes are to demonstrate detailed geological mapping with 3D rendering techniques, to generate LiDAR-derived 3D strata boundaries that are advantageous in generating 2D geological maps and cross sections, and to develop a new practice in deriving the strike and dip of bedding with LiDAR data using an example from the north bank of the Keelung River in northern Taiwan. We propose a geological mapping practice that improves efficiency and meets a high-precision mapping standard with up to 2 m resolution using airborne LiDAR data. Through field verification and assessment, LiDAR data manipulation with relevant 3D visualization is shown to be an effective approach in improving the details of existing geological maps, specifically in sedimentary terrain.

Geologic map of outcrop areas of sedimentary units in the eastern part of the Hailey 1 degree x 2 degrees quadrangle and part of the southern part of the Challis 1 degree x 2 degrees quadrangle, south-central Idaho

Science.gov (United States)

Link, P.K.; Mahoney, J.B.; Bruner, D.J.; Batatian, L.D.; Wilson, Eric; Williams, F.J.C.

1995-01-01

The paper version of the Geologic map of outcrop areas of sedimentary units in the eastern part of the Hailey 1x2 Quadrangle and part of the southern part of the Challis 1x2 Quadrangle, south-central Idaho was compiled by Paul Link and others in 1995. The plate was compiled on a 1:100,000 scale topographic base map. TechniGraphic System, Inc. of Fort Collins Colorado digitized this map under contract for N.Shock. G.Green edited and prepared the digital version for publication as a GIS database. The digital geologic map database can be queried in many ways to produce a variety of geologic maps.

Seeking Signs of Life on Mars: The Importance of Sedimentary Suites as Part of Mars Sample Return

Science.gov (United States)

iMOST Team; Mangold, N.; McLennan, S. M.; Czaja, A. D.; Ori, G. G.; Tosca, N. J.; Altieri, F.; Amelin, Y.; Ammannito, E.; Anand, M.; Beaty, D. W.; Benning, L. G.; Bishop, J. L.; Borg, L. E.; Boucher, D.; Brucato, J. R.; Busemann, H.; Campbell, K. A.; Carrier, B. L.; Debaille, V.; Des Marais, D. J.; Dixon, M.; Ehlmann, B. L.; Farmer, J. D.; Fernandez-Remolar, D. C.; Fogarty, J.; Glavin, D. P.; Goreva, Y. S.; Grady, M. M.; Hallis, L. J.; Harrington, A. D.; Hausrath, E. M.; Herd, C. D. K.; Horgan, B.; Humayun, M.; Kleine, T.; Kleinhenz, J.; Mackelprang, R.; Mayhew, L. E.; McCubbin, F. M.; McCoy, J. T.; McSween, H. Y.; Moser, D. E.; Moynier, F.; Mustard, J. F.; Niles, P. B.; Raulin, F.; Rettberg, P.; Rucker, M. A.; Schmitz, N.; Sefton-Nash, E.; Sephton, M. A.; Shaheen, R.; Shuster, D. L.; Siljestrom, S.; Smith, C. L.; Spry, J. A.; Steele, A.; Swindle, T. D.; ten Kate, I. L.; Usui, T.; Van Kranendonk, M. J.; Wadhwa, M.; Weiss, B. P.; Werner, S. C.; Westall, F.; Wheeler, R. M.; Zipfel, J.; Zorzano, M. P.

2018-04-01

Sedimentary, and especially lacustrine, depositional environments are high-priority geological/astrobiological settings for Mars Sample Return. We review the detailed investigations, measurements, and sample types required to evaluate such settings.

Geodatabase model for global geologic mapping: concept and implementation in planetary sciences

Science.gov (United States)

Nass, Andrea

2017-04-01

One aim of the NASA Dawn mission is to generate global geologic maps of the asteroid Vesta and the dwarf planet Ceres. To accomplish this, the Dawn Science Team followed the technical recommendations for cartographic basemap production. The geological mapping campaign of Vesta was completed and published, but mapping of the dwarf planet Ceres is still ongoing. The tiling schema for the geological mapping is the same for both planetary bodies and for Ceres it is divided into two parts: four overview quadrangles (Survey Orbit, 415 m/pixel) and 15 more detailed quadrangles (High Altitude Mapping HAMO, 140 m/pixel). The first global geologic map was based on survey images (415 m/pixel). The combine 4 Survey quadrangles completed by HAMO data served as basis for generating a more detailed view of the geologic history and also for defining the chronostratigraphy and time scale of the dwarf planet. The most detailed view can be expected within the 15 mapping quadrangles based on HAMO resolution and completed by the Low Altitude Mapping (LAMO) data with 35 m/pixel. For the interpretative mapping process of each quadrangle one responsible mapper was assigned. Unifying the geological mapping of each quadrangle and bringing this together to regional and global valid statements is already a very time intensive task. However, another challenge that has to be accomplished is to consider how the 15 individual mappers can generate one homogenous GIS-based project (w.r.t. geometrical and visual character) thus produce a geologically-consistent final map. Our approach this challenge was already discussed for mapping of Vesta. To accommodate the map requirements regarding rules for data storage and database management, the computer-based GIS environment used for the interpretative mapping process must be designed in a way that it can be adjusted to the unique features of the individual investigation areas. Within this contribution the template will be presented that uses standards

In-situ heater test in sedimentary soft rocks under high temperature (Phase I)

International Nuclear Information System (INIS)

Ikenoya, Takafumi; Takakura, Nozomu; Okada, Tetsuji; Sawada, Masataka; Hirano, Kouhei; Tani, Kazuo

2008-01-01

Various researches have been conducted on high level radioactive waste geological disposal in sedimentary soft rocks. It's noted that the long-term mechanical behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperatures or hydraulic conditions. Therefore, in-situ heater test was conducted in an underground cavern at a depth of 50 meters for the purpose of improving thermo-hydro-mechanical coupled analysis code. This report presents the test result demonstrating the changes of temperature and strain distributions with time at the elevated temperature of the heater up to 40 degrees Celsius. (author)

Geologic history of the Slick Rock district and vicinity, San Miguel and Dolores Counties, Colorado

International Nuclear Information System (INIS)

Shawe, D.R.

1976-01-01

This report is a narrative summary and interpretation, in the form of a geologic history of the Slick Rock district and vicinity, of four previously published chapters in this series dealing with stratigraphy of the Slick Rock district and vicinity, petrography of sedimentary rocks of the district, structure of the district and vicinity, and altered sedimentary rocks of the district, and of other previously published reports on the district. It forms the background, with the earlier reports, for presentation of a final report in the series describing the uranium-vanadium ore deposits. A review of the origin of sedimentary rocks and geologic history of the region indicates that formation of uranium-vanadium deposits was a natural result of the deposition of th rocks, the occurrence of intrastratal waters therein, and the post-depositional movement of the waters resulting from evolution of the sedimentary rock environment. 31 refs

Improving the effectiveness of geological prospecting with neutron activation analysis

International Nuclear Information System (INIS)

Fardy, J.J.

1984-01-01

Two examples of the use of neutron activation analysis to improve the effectiveness of geological prospecting are examined. The first is application to the direct hydrogeochemical prospecting for gold in surface waters. The second shows how multielement data banks produced by NAA for a geological formation provide a powerful method for the classification of ore bodies and sedimentary materials

VOSGES, a long and rich geologic history

Science.gov (United States)

Dominique, Carteaux; Cyrille, Delangle; Sophie, Demangel

2015-04-01

The study of geology in scientific classes is often too theoretical and abstract for the pupils. How can teachers make the link between some samples of rocks observed in a practical class and the geologic story of the region? There's nothing better than outdoor education to establish a relationship between the rock observed in macroscopic and microscopic scale in the classroom,with the outcrop scale and the landscape scale in the field: all of them are the result of a fascinating geologic history.Our pupils are lucky enough to live at the heart of a modest mountain massif that has a very rich geologic story: the massif from Vosges situated in the east of France. During two expeditions we show the students all the following tectonic processes: Accretion at the scale of the landscape with the Rhenish Ditch (tectonic and volcanic markers) Obductionis observed due to ophiolites found in the massive of Thalhorn (peridotite, gabbro and sedimentary marine rocks of great depth). Collisionis illuminated with numerous sites like the schists of Steige, the phyllite of Villé, the gneisses of Climont. Subductionis captured bystudying the outcrops of magmatic rocks within the continental crust (andesite, diorite, granodiorite). At each of the stops we have the students, from a hand sample, to findits story in a more global context. So the theory becomes reality. A study of thin slides of rocks observed on the ground finishes these exits and so various scales of understanding are approached. The long and rich geologic history of Vosges maybe reconstituted on hundreds of million years, allowing certainly giving another aspect to the living environment of our pupils.

Constraining the Antarctic contribution to global sea-level change: ANDRILL and beyond

Science.gov (United States)

Naish, Timothy

2016-04-01

Observations, models and paleoclimate reconstructions suggest that Antarctica's marine-based ice sheets behave in an unstable manner with episodes of rapid retreat in response to warming climate. Understanding the processes involved in this "marine ice sheet instability" is key for improving estimates of Antarctic ice sheet contribution to future sea-level rise. Another motivating factor is that far-field sea-level reconstructions and ice sheet models imply global mean sea level (GMSL) was up to 20m and 10m higher, respectively, compared with present day, during the interglacials of the warm Pliocene (~4-3Ma) and Late Pleistocene (at ~400ka and 125ka). This was when atmospheric CO2 was between 280 and 400ppm and global average surface temperatures were 1 to 3°C warmer, suggesting polar ice sheets are highly sensitive to relatively modest increases in climate forcing. Such magnitudes of GMSL rise not only require near complete melt of the Greenland Ice Sheet and the West Antarctic Ice Sheet, but a substantial retreat of marine-based sectors of East Antarctic Ice Sheet. Recent geological drilling initiatives on the continental margin of Antarctica from both ship- (e.g. IODP; International Ocean Discovery Program) and ice-based (e.g. ANDRILL/Antarctic Geological Drilling) platforms have provided evidence supporting retreat of marine-based ice. However, without direct access through the ice sheet to archives preserved within sub-glacial sedimentary basins, the volume and extent of ice sheet retreat during past interglacials cannot be directly constrained. Sediment cores have been successfully recovered from beneath ice shelves by the ANDRILL Program and ice streams by the WISSARD (Whillans Ice Stream Sub-glacial Access Research Drilling) Project. Together with the potential of the new RAID (Rapid Access Ice Drill) initiative, these demonstrate the technological feasibility of accessing the subglacial bed and deeper sedimentary archives. In this talk I will outline the

Estimate of the Geothermal Energy Resource in the Major Sedimentary Basins in the United States (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Esposito, A.; Porro, C.; Augustine, C.; Roberts, B.

2012-09-01

Because most sedimentary basins have been explored for oil and gas, well logs, temperatures at depth, and reservoir properties such as depth to basement and formation thickness are well known. The availability of this data reduces exploration risk and allows development of geologic exploration models for each basin. This study estimates the magnitude of recoverable geothermal energy from 15 major known U.S. sedimentary basins and ranks these basins relative to their potential. The total available thermal resource for each basin was estimated using the volumetric heat-in-place method originally proposed by (Muffler, 1979). A qualitative recovery factor was determined for each basin based on data on flow volume, hydrothermal recharge, and vertical and horizontal permeability. Total sedimentary thickness maps, stratigraphic columns, cross sections, and temperature gradient information was gathered for each basin from published articles, USGS reports, and state geological survey reports. When published data were insufficient, thermal gradients and reservoir properties were derived from oil and gas well logs obtained on oil and gas commission databases. Basin stratigraphy, structural history, and groundwater circulation patterns were studied in order to develop a model that estimates resource size, temperature distribution, and a probable quantitative recovery factor.

'Anthropocene': An Ethical Crisis, Not a Geological Epoch

Science.gov (United States)

Cuomo, Chris

2017-04-01

The term 'anthropocene' has gained enormous popularity among scientists who believe we are in a global phase distinguished by the extensive and lasting impacts of social activities on Earth's sedimentary record and vital systems. Beyond its widespread informal use, a working group of the International Union of Geological Sciences seeks to formalize the term to name a new geological epoch, implying that the Holocene epoch has ended. I argue that the move to formalize the 'anthropocene' and to declare the demise of the Holocene is premature and ethically misguided, at best, and that the very name 'anthropocene' obscures rather than illuminates the serious moral and political/economic implications of the dire warnings evident in recent stratigraphic and ecological changes. If human-caused mass extinction and other ecological catastrophes are serious harms, ethical responses are required. Instead, the move to formalize the idea of an 'anthropocene' epoch treats dire ethical warnings as an opportunity to redefine the current dangerous situation as a new status quo. Have we met our responsibilities to protect Holocene Earth? This presentation will focus on the ethical implications of using the power and discourse of geology to demote Holocene ecological states from their role as the foundational benchmarks for guiding and assessing human relationships with nature and other species. Have geoscientists adequately consulted the biological, ecological and social sciences before declaring the end of the Holocene epoch? Upon what do we base environmental ethics if the Holocene is considered past history? I will also examine the ethical dimensions of naming the so-called 'anthropocene', asking: who is the presumed 'anthro' in the 'anthropocene'? Are the phenomena identified with the 'anthropocene' (nuclear fallout, mass species endangerment, ocean acidification, fossil fuel pollution, deforestation, mining) definitive accomplishments of the human species? Should the practices

Effect of hydro mechanical coupling on natural fracture network formation in sedimentary basins

Science.gov (United States)

Ouraga, Zady; Guy, Nicolas; Pouya, Amade

2018-05-01

In sedimentary basin context, numerous phenomena, depending on the geological time span, can result in natural fracture network formation. In this paper, fracture network and dynamic fracture spacing triggered by significant sedimentation rate are studied considering mode I fracture propagation using a coupled hydro-mechanical numerical methods. The focus is put on synthetic geological structure under a constant sedimentation rate on its top. This model contains vertical fracture network initially closed and homogeneously distributed. The fractures are modelled with cohesive zone model undergoing damage and the flow is described by Poiseuille's law. The effect of the behaviour of the rock is studied and the analysis leads to a pattern of fracture network and fracture spacing in the geological layer.

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.

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

International Nuclear Information System (INIS)

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

Surveying Geology Concepts in Education Standards for a Rapidly Changing Global Context

Science.gov (United States)

Guffey, Sarah K.; Slater, Stephanie J.; Schleigh, Sharon P.; Slater, Timothy F.; Heyer, Inge

2016-01-01

Internationally much attention is being paid to which of a seemingly endless list of scientific concepts should be taught to schoolchildren to enable them to best participate in the global economy of the 21st Century. In regards to science education, the concepts framing the subject of geology holds exalted status as core scientific principles in…

The geology of the southeastern Baltic Sea: a review

Science.gov (United States)

Ūsaitytė, Daiva

2000-06-01

The Baltic Sea, particularly its southeastern part, is discussed in the paper. Investigations of regional character as well as specialized studies in the area are reviewed. General historical works are mentioned briefly. Previous surveys since the 1950s are presented by the subject studied. The compilation of geological structure of the SE Baltic Sea bottom and adjacent land of Balticum (Baltic States: Estonia, Latvia, Lithuania) is based on considerable amounts of summarized materials. The crystalline basement, sedimentary cover and Quaternary deposits are characterized in the comprehensive survey of geological structure. From a stratigraphical point of view, geological sequence of the platformal cover is comparatively complete: deposits of all geological systems (from the Archean to Cenozoic) are present in the Baltic Syneclise. Considering geotectonical cycles, the sedimentary cover of the syneclise is subdivided into four structural complexes. The thickness and distribution of Quaternary deposits are closely related to the recent bottom relief of the Baltic Sea that in turn is inherited from the Pre-Quaternary surface. Buried palaeo-valleys are characteristic of the Pre-Quaternary surface in the Baltic region and the Baltic Sea bottom. The Quaternary is characterized by layers of various geneses and by sharp changes of their thicknesses.

Geologic map of the Cochiti Dam quadrangle, Sandoval County, New Mexico

Science.gov (United States)

Dethier, David P.; Thompson, Ren A.; Hudson, Mark R.; Minor, Scott A.; Sawyer, David A.

2011-01-01

The Cochiti Dam quadrangle is located in the southern part of the Española Basin and contains sedimentary and volcanic deposits that record alluvial, colluvial, eolian, tectonic and volcanic processes over the past seventeen million years. The geology was mapped from 1997 to 1999 and modified in 2004 to 2008. The primary mapping responsibilities were as follows: Dethier mapped the surficial deposits, basin-fill sedimentary deposits, Miocene to Quaternary volcanic deposits of the Jemez volcanic field, and a preliminary version of fault distribution. Thompson and Hudson mapped the Pliocene and Quaternary volcanic deposits of the Cerros del Rio volcanic field. Thompson, Minor, and Hudson mapped surface exposures of faults and Hudson conducted paleomagnetic studies for stratigraphic correlations. Thompson prepared the digital compilation of the geologic map.

Geology of the Horse Range Mesa quadrangle, Colorado

Science.gov (United States)

Cater, Fred W.; Bush, A.L.; Bell, Henry; Withington, C.F.

1953-01-01

The Horse Range Mesa quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of the quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary strictures in sandstones of favorable composition.

The geology of the surrounding metamorphic rock of Zaer granite (Morocco): contribution to the search for uranium

International Nuclear Information System (INIS)

Mathias, Laurent

1984-01-01

This research thesis reports a study which aimed at reconstituting the geological history of the Zaer region in Morocco with objectives of mining exploration and of assessment of its uranium metallogenic potential. The author examined the whole geological context by studying stratigraphy, sedimentology, tectonic, and petrography of rocks belonging to the concerned area. The main objective was to determine the origin of uranium between a granitic one and a sedimentary one. This meant a reconstitution of the geological history, and therefore the study of the metamorphized sedimentary surrounding rock, of the intrusive granite and of their different possible relationships. On a first part, the author analysed outcropping formations and tried to assign them with a stratigraphic position. He also tried to define the deposition modalities of these formations which could have conditioned sedimentary sites. In a second part, the author reports the study of geological structures and tectonic in order to try to recognise possible structures which could have promoted uranium deposition and trapping in the surrounding rock as well as in granite. The last part addresses the petrography of the different rocks met in the area, and mineralization, notably that of uranium [fr

Combined crustal-geological cross-section of Ellesmere Island

DEFF Research Database (Denmark)

Stephenson, Randell Alexander; Schiffer, Christian; Oakey, Gordon

are reported in detail in another presentation at this symposium (Schiffer et al.). Moho depth, a number of intracrustal horizons and sedimentary thicknesses can be inferred. Meanwhile, geological mapping on Ellesmere Island in the framework of BGR’s (Germany) CASE (“Circum-Arctic Structural Events”) programme...

Relationship between water quality of deep-groundwater and geology in non-volcanic areas in Japan

International Nuclear Information System (INIS)

Oyama, Yoichi; Takahashi, Masaaki; Tsukamoto, Hitoshi; Kazahaya, Kohei; Yasuhara, Masaya; Takahashi, Hiroshi; Morikawa, Noritoshi; Ohwada, Michiko; Shibahara, Akihiko; Inamura, Akihiko

2011-01-01

Geochemical characteristics in groundwater such as groundwater chemistry and physicochemical parameters are affected by their source and the interaction with rocks and minerals. We observed the relationships between groundwater chemistry of the deep-groundwater and the geology in non-volcanic areas in Japan using about 9300 of deep-groundwater data. A Geographical Information System (GIS) was used to extract data in non-volcanic areas and numbers of water data are about 5200. The data were further classified into four types of geology (sedimentary rock, accretionary complex, volcanic rock and plutonic rock). The pH, temperature and major ion concentrations among deep-groundwaters in each geology have been statistically analysed. Result shows that the total cation concentration of deep-groundwaters are significantly different between geology, and the average values are decreased in the order of the sedimentary rock (66.7 meq l -1 ), volcanic rock (43.0 meq l -1 ), accretionary complex (24.6 meq l -1 ), and plutonic rock (11.0 meq l -1 ). The average pH does not show the major difference between geology whereas the highest average temperature is found in volcanic rock. In addition, the all four major cations (Na, K, Mg, and Ca) show the highest average concentrations in sedimentary rock, within the highest average concentrations of major anions for Cl, SO 4 , and HCO 3 are found in sedimentary rock, volcanic rock and accretionary complex, respectively, indicating the difference of the influence on the anions varied with geology. The distribution of deep-groundwater that are dominated by each major anions implied that SO 4 -type groundwater in volcanic rocks are formed by the influence of Neogene volcanic rock (Green tuff). In addition, HCO 3 -type groundwater in accretionary complex found from Kinki to Shikoku regions are formed by the addition of CO 2 gases supplying not only from surface soil and carbonate minerals but from deep underground. (author)

Subsurface geology off Bombay with paleoclimatic inferences interpreted from shallow seismic profiles

Digital Repository Service at National Institute of Oceanography (India)

Bhattacharya, G.C.; Almeida, F.; Vora, K.H.; Siddiquie, H.N.

High resolution seismic reflection profiles nearshore areas off Bombay provide information on subsurface geology and permit certain paleoclimatic inferences. Three sedimentary units overlie the acoustic basement: late Pleistocene consolidated...

Global Geological Map of Venus

Science.gov (United States)

Ivanov, M. A.

2008-09-01

Introduction: The Magellan SAR images provide sufficient data to compile a geological map of nearly the entire surface of Venus. Such a global and selfconsistent map serves as the base to address the key questions of the geologic history of Venus. 1) What is the spectrum of units and structures that makes up the surface of Venus [1-3]? 2) What volcanic/tectonic processes do they characterize [4-7]? 3) Did these processes operated locally, regionally, or globally [8- 11]? 4) What are the relationships of relative time among the units [8]? 5) At which length-scale these relationships appear to be consistent [8-10]? 6) What is the absolute timing of formation of the units [12-14]? 7) What are the histories of volcanism, tectonics and the long-wavelength topography on Venus? 7) What model(s) of heat loss and lithospheric evolution [15-21] do these histories correspond to? The ongoing USGS program of Venus mapping has already resulted in a series of published maps at the scale 1:5M [e.g. 22-30]. These maps have a patch-like distribution, however, and are compiled by authors with different mapping philosophy. This situation not always results in perfect agreement between the neighboring areas and, thus, does not permit testing geological hypotheses that could be addressed with a self-consistent map. Here the results of global geological mapping of Venus at the scale 1:10M is presented. The map represents a contiguous area extending from 82.5oN to 82.5oS and comprises ~99% of the planet. Mapping procedure: The map was compiled on C2- MIDR sheets, the resolution of which permits identifying the basic characteristics of previously defined units. The higher resolution images were used during the mapping to clarify geologic relationships. When the map was completed, its quality was checked using published USGS maps [e.g., 22-30] and the catalogue of impact craters [31]. The results suggest that the mapping on the C2-base provided a highquality map product. Units and

Mineralogy and depositional sources of sedimentary interbeds beneath the Idaho National Engineering Laboratory; eastern Snake River Plain, Idaho

International Nuclear Information System (INIS)

Reed, M.F.

1994-01-01

Idaho State University, in cooperation with the U.S. Geological Survey, and the U.S. Department of Energy, collected 57 samples of sedimentary interbeds at 19 sites at the Idaho National Engineering Laboratory (INEL) for mineralogical analysis. Previous work by the U.S. Geological Survey on surficial sediments showed that ratios detrital of quartz, total feldspars, and calcite can be used to distinguish the sedimentary mineralogy of specific stream drainages at the INEL. Semi-quantitative x-ray diffraction analyses were used to determine mineral abundances in the sedimentary interbeds. Samples were collected from wells at the New Production Reactor (NPR) area, Idaho Chemical Processing Plant (ICPP), Test Reactor Area (TRA), miscellaneous sites, Radioactive Waste Management Complex (RWMC), Naval Reactors Facility (NRF), and Test Area North (TAN). Normalized mean percentages of quartz, feldspar, and carbonate were calculated from sample data sets at each site. Percentages for quartz, feldspar, and carbonate from the NPR, ICPP, TRA, miscellaneous sites, RWMC, and NRF ranged from 37 to 59, 26 to 40, and 5 to 25, respectively. Percentages for quartz, feldspar, and carbonate from wells at Test Area North (TAN) were 24, 10, and 66, respectively. Mineralogical data indicate that sedimentary interbed samples collected from the NPR, ICPP, TRA, miscellaneous sites, RWMC, and NRF correlate with surficial sediment samples from the present day Big Lost River. Sedimentary interbeds from TAN sites correlate with surficial sediment samples from Birch Creek. These correlations suggest that the sources for the sediments at and near the INEL have remained relatively consistent for the last 580,000 years. 12 refs., 4 figs., 3 tabs

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

International Nuclear Information System (INIS)

Yoshida, H.; Metcalfe, R.; Yamamoto, K.; Murakami, Y.; Hoshii, D.; Kanekiyo, A.; Naganuma, T.; Hayashi, T.

2008-01-01

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Yoshida, H. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan)], E-mail: dora@num.nagoya-u.ac.jp; Metcalfe, R. [Quintessa Japan, Queen' s Tower A7-707, Minatomirai, Yokohama 220-6007 (Japan); Yamamoto, K. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan); Murakami, Y. [Japan Atomic Energy Agency (JAEA), Tono Geoscience Centre (Japan); Hoshii, D.; Kanekiyo, A.; Naganuma, T. [Hiroshima University, Higashi Hiroshima, Kagamiyama 1-4-4 (Japan); Hayashi, T. [Asahi University, Department of Dental Pharmacology, Hozumi, Gifu (Japan)

2008-08-15

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure.

Integrated techniques to evaluate the features of sedimentary rocks of archaeological areas of Sicily

Directory of Open Access Journals (Sweden)

Maria Brai

2004-02-01

Full Text Available Sicily includes a great variety of lithologies, giving a high complexity to the geologic landscape. Their prevalent lithology is sedimentary. It is well known that rocks of sedimentary origin, compared with metamorphic and volcanic deposits, can be relatively soft and hence fairly easy to model. Nevertheless, this workability advantage is a drawback for Cultural Heritage applications. In fact, these materials show a high porosity, with pore-size distributions that lead to deterioration through absorption of water. In this paper, several sedimentary rocks used in historical Cultural Heritage items of Sicily, from "Magna Graecia" to nowadays, are classified for mineralogical features, chemical composition, and for porosity. Particularly, some samples collected in quarries relevant to the archaeological sites of 41 Agrigento, Segesta and Selinunte will be considered and characterized using integrated techniques (XRD, XRF, NMR and CT. Data on samples obtained in laboratory will be compared with the relevant values measured in situ on monuments of historical-cultural interest of the quoted archaeological places.

Petrological-geochemical characteristics of coarse-grained clastic sedimentary rocks of Quantou Formation, Cretaceous in Songliao basin and their geological significance

International Nuclear Information System (INIS)

Wang Gan; Zhang Bangtong

2005-01-01

Clastic sedimentary rocks of Quantou Formation, Cretaceous in Qing-an area, Songliao basin are mainly composed of sandstone, mudstone and siltstone. The petrological-chemical analysis of clastic sedimentary rocks from Quantou Formation, Cretaceous indicates that their lithology mainly consists of arkose, shale and minor rock debris sandstone and greywacke by chemical classification of bulk elements. REE distribution pattern displays the apparent enrichment of LREE and negative anomaly of Eu and is similar to that of NASC and PAAS. The ratio of trace-element in sedimentary rocks to that of upper crust shows gentle character. All the above features indicate that these sedimentary rocks were slowly deposited under weakly active tectonic setting. They are sediments typical for passive continental margin and active continental margin. It is suggested that material source of clastic sediments of Quantou Formation, Cretaceous in Qing-an area, Songliao basin was originated from Hercynian granite of Zhangguangchai Mountain, and the granite was originated from upper crust. (authors)

Geological and Petrographic Characteristics of Kimberlite Pipes

Directory of Open Access Journals (Sweden)

N. N. Zinchuk

2016-12-01

Full Text Available Studies of the geological structure and petrochemical composition of the Siberian Platform kimberlites indicated complexity, diversity of geological, tectonic, and paleogeographic situations, which must be considered for proper prospecting-exploration for diamonds in each area of investigation. Information about petrochemical composition of potential diatremes, hosting, and overlying sedimentary and magmatic formations is an important prerequisite for prospecting of kimberlite deposits in different geologic-tectonic conditions. The most attention should be paid to typomorphic specific features of primary and secondary minerals of diatremes. Each diamondiferous region is characterized by a certain set of typomorphic associations of kimberlites primary and secondary minerals. The diamonds with ultrabasic association of solid phase inclusions (olivine, chrome-spinel, pyrope, etc. dominate in majority of kimberlite pipes.

A geologic approach to field methods in fluvial geomorphology

Science.gov (United States)

Fitzpatrick, Faith A.; Thornbush, Mary J; Allen, Casey D; Fitzpatrick, Faith A.

2014-01-01

A geologic approach to field methods in fluvial geomorphology is useful for understanding causes and consequences of past, present, and possible future perturbations in river behavior and floodplain dynamics. Field methods include characterizing river planform and morphology changes and floodplain sedimentary sequences over long periods of time along a longitudinal river continuum. Techniques include topographic and bathymetric surveying of fluvial landforms in valley bottoms and describing floodplain sedimentary sequences through coring, trenching, and examining pits and exposures. Historical sediment budgets that include floodplain sedimentary records can characterize past and present sources and sinks of sediment along a longitudinal river continuum. Describing paleochannels and floodplain vertical accretion deposits, estimating long-term sedimentation rates, and constructing historical sediment budgets can assist in management of aquatic resources, habitat, sedimentation, and flooding issues.

Study on flow and mass transport through fractured soft sedimentary rocks (Contact research)

International Nuclear Information System (INIS)

Shimo, Michito; Kumamoto, Sou; Maekawa, Keisuke

2007-03-01

It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground accurately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. The objective of this study is to establish a conceptual model for flow and mass transport in fractured soft sedimentary rock. In previous study, a series of laboratory hydraulic and tracer tests and numerical analyses were carried out using sedimentary rock specimens obtained from Koetoi and Wakkanai formation. Single natural fractured cores and rock block specimen were used for the tests and analyses. The results indicated that the matrix diffusion played an important role for mass transport in the fractured soft sedimentary rocks. In this study, the following two tasks were carried out: (1) laboratory hydraulic and tracer experiments of rock cores of Koetoi and Wakkanai formation obtained at HDB-9, HDB-10 and HDB-11 boreholes and a rock block specimen, Wakkanai formation, obtained at an outcrop in the Horonobe area, (2) a numerical study on the conceptual model of flow and mass transport through fractured soft sedimentary rocks. Non-sorbing tracer experiments using naturally fractured cores and rock block specimens were carried out. Pottasium iodide was used as a tracer. The obtained breakthrough curves were interpreted and fitted by using a numerical simulator, and mass transport parameters, such as longitudinal dispersivity, matrix diffusion coefficient, transport aperture, were obtained. Mass transport simulations using a fracture network model, a continuum model and a double porosity model were performed to study the applicability of continuum model and double porosity model for transport in fractured sedimentary rock. (author)

Environmental marine geology of the Arctic Ocean

International Nuclear Information System (INIS)

Mudie, P.J.

1991-01-01

The Arctic Ocean and its ice cover are major regulators of Northern Hemisphere climate, ocean circulation and marine productivity. The Arctic is also very sensitive to changes in the global environment because sea ice magnifies small changes in temperature, and because polar regions are sinks for air pollutants. Marine geology studies are being carried out to determine the nature and rate of these environmental changes by study of modem ice and sea-bed environments, and by interpretation of geological records imprinted in the sea-floor sediments. Sea ice camps, an ice island, and polar icebreakers have been used to study both western and eastern Arctic Ocean basins. Possible early warning signals of environmental changes in the Canadian Arctic are die-back in Arctic sponge reefs, outbreaks of toxic dinoflagellates, and pesticides in the marine food chain. Eastern Arctic ice and surface waters are contaminated by freon and radioactive fallout from Chernobyl. At present, different sedimentary processes operate in the pack ice-covered Canadian polar margin than in summer open waters off Alaska and Eurasia. The geological records, however, suggest that a temperature increase of 1-4 degree C would result in summer open water throughout the Arctic, with major changes in ocean circulation and productivity of waters off Eastern North America, and more widespread transport of pollutants from eastern to western Arctic basins. More studies of longer sediment cores are needed to confirm these interpretations, but is is now clear that the Arctic Ocean has been the pacemaker of climate change during the past 1 million years

Geochemical parameters of radioelements applied to assess uranium prospects in geological formation

International Nuclear Information System (INIS)

Ma Zhongxiang.

1988-01-01

Based on geochemical characteristics of radioelements and the theory of facieology, the author describes the characteristics of the distribution of U, Th and K in sedimentary formation and the relationship between their combined parameters MA and MB and uranium mineralization in geological formation. The ranges of MA and MB in uraniferous geological formation used to assess four different levels of uranium mineralization in regional investigation are obtained from the comparision of combined parameters MA and MB in the geological formation with different levels of mineralization and the experience is provided for quantitatively assessing uranium prospects in geological by multi-parameter model of radioelements

Soils and Global Change in the Carbon Cycle over Geological Time

Science.gov (United States)

Retallack, G. J.

2003-12-01

sedimentary rocks; organic matter burial is an important long-term control on CO2 levels in the atmosphere (Berner and Kothavala, 2001). The magnitudes of carbon pools and fluxes involved provide a perspective on the importance of soils compared with other carbon reservoirs ( Figure 1). (6K)Figure 1. Pools and fluxes of reduced carbon (bold) and oxidized carbon (regular) in Gt in the pre-industrial carbon cycle (sources Schidlowski and Aharon, 1992; Siegenthaler and Sarmiento, 1993; Stallard, 1998). Before industrialization, there was only 600 Gt (1 Gt=1015g) of carbon in CO2 and methane in the atmosphere, which is about the same amount as in all terrestrial biomass, but less than half of the reservoir of soil organic carbon. The ocean contained only ˜3 Gt of biomass carbon. The deep ocean and sediments comprised the largest reservoir of bicarbonate and organic matter, but that carbon has been kept out of circulation from the atmosphere for geologically significant periods of time (Schidlowski and Aharon, 1992). Humans have tapped underground reservoirs of fossil fuels, and our other perturbations of the carbon cycle have also been significant ( Vitousek et al., 1997b; see Chapter 8.10).Atmospheric increase of carbon in CO2 to 750 Gt C by deforestation and fossil fuel burning has driven ongoing global warming, but is not quite balanced by changes in the other carbon reservoirs leading to search for a "missing sink" of some 1.8±1.3 GtC, probably in terrestrial organisms, soils, and sediments of the northern hemisphere (Keeling et al., 1982; Siegenthaler and Sarmiento, 1993; Stallard, 1998). Soil organic matter is a big, rapidly cycling reservoir, likely to include much of this missing sink.During the geological past, the sizes of, and fluxes between, these reservoirs have varied enormously as the world has alternated between greenhouse times of high carbon content of the atmosphere, and icehouse times of low carbon content of the atmosphere. Oscillations in the atmospheric

Magmatism in the brazilian sedimentary basins and the petroleum geology; Magmatismo nas bacias sedimentares brasileiras e sua influencia na geologia do petroleo

Energy Technology Data Exchange (ETDEWEB)

Thomaz Filho, Antonio; Antonioli, Luzia [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Faculdade de Geologia]. E-mails: antoniothomaz@globo.com; antonioli@novanet.com.br; Mizusaki, Ana Maria Pimentel [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias]. E-mail: ana.mizusaki@ufrgs.br

2008-06-15

In the recent years, the researches on the magmatic events that occurred in the Brazilian sedimentary basins had shown the importance of these episodes for the hydrocarbons exploration. The generation (heating), migration (structural and petrographic alterations), accumulation (basalt fractures) and migrations barriers (sills and dykes) of the hydrocarbons, produced for these rocks, are cited in the marginal and intra continental Brazilian basins. The magmatism produce the temperature increase in the sedimentary basin, around its intrusion, and this propitiate the maturation of the organic matter contained in the hydrocarbons generating rocks of the basin. At the same time, has been verified that the contacts dykes/sedimentary rocks can represent important ways for the hydrocarbons migrations. Recent studies have shown that the magmatism, in its extrusive manifestations, can be analyzed in view of the possibility of having acted as effective hydrocarbon seals and, in consequence, making possible the accumulation of hydrocarbons generated in the underlying sediments. The magmatism of predominantly basic to intermediary character is generated in the asthenosphere, that is, below the lithosphere. The dykes that had introduced in the basement of our sedimentary basins are good heat conductors and we can expect the geothermal gradients increase in the overlapped sedimentary deposits. The more detailed study of the magmatic processes in the Brazilian sedimentary basins must lead to new forms of hydrocarbons exploration in our sedimentary basins, also in those basins where the traditional exploration activities have not occasioned the waited expected successes. (author)

Medical Geology: a globally emerging discipline

Energy Technology Data Exchange (ETDEWEB)

Bunnell, J.E.; Finkelman, R.B.; Centeno, J.A.; Selinus, O. [Armed Forces Institute of Pathology, Washington, DC (United States)

2007-07-01

Medical Geology, the study of the impacts of geologic materials and processes on animal and human health, is a dynamic emerging discipline bringing together the geoscience, biomedical, and public health communities to solve a wide range of environmental health problems. Among the Medical Geology described in this review are examples of both deficiency and toxicity of trace element exposure. Goiter is a widespread and potentially serious health problem caused by deficiency of iodine. In many locations the deficiency is attributable to low concentrations of iodine in the bedrock. Similarly, deficiency of selenium in the soil has been cited as the principal cause of juvenile cardiomyopathy and muscular abnormalities. Overexposure to arsenic is one of the most widespread Medical Geology problems affecting more than one hundred million people in Bangladesh, India, China, Europe, Africa and North and South America. The arsenic exposure is primarily due to naturally high levels in groundwater but combustion of mineralized coal has also caused arsenic poisoning. Dental and skeletal fluorosis also impacts the health of millions of people around the world and, like arsenic, is due to naturally high concentrations in drinking water and, to a lesser extent, coal combustion. Other Medical Geology issues described include geophagia, the deliberate ingestion of soil, exposure to radon, and ingestion of high concentrations of organic compounds in drinking water. Geoscience and biomedical/public health researchers are teaming to help mitigate these health problems as well as various non-traditional issues for geoscientists such as vector-borne diseases.

Postclosure safety assessment of a used fuel repository in sedimentary rock

International Nuclear Information System (INIS)

Gobien, M.; Garisto, F.; Hunt, N.; Kremer, E.

2014-01-01

The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management (APM), the federally-approved plan for safe long-term management of Canada's used nuclear fuel. Under the APM plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable rock formation. This paper summarizes an illustrative case study of the current multi-barrier design and postclosure safety of a deep geological repository in a hypothetical sedimentary Michigan Basin setting. The purpose of this postclosure safety assessment is to determine potential effects of the repository on the health and safety of persons and the environment. Results are compared against acceptance criteria established for the protection of persons and the environment from potential radiological and non-radiological hazards. (author)

Postclosure safety assessment of a used fuel repository in sedimentary rock

Energy Technology Data Exchange (ETDEWEB)

Gobien, M.; Garisto, F.; Hunt, N.; Kremer, E. [Nuclear Waste Management Organization, Toronto, ON (Canada)

2014-07-01

The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management (APM), the federally-approved plan for safe long-term management of Canada's used nuclear fuel. Under the APM plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable rock formation. This paper summarizes an illustrative case study of the current multi-barrier design and postclosure safety of a deep geological repository in a hypothetical sedimentary Michigan Basin setting. The purpose of this postclosure safety assessment is to determine potential effects of the repository on the health and safety of persons and the environment. Results are compared against acceptance criteria established for the protection of persons and the environment from potential radiological and non-radiological hazards. (author)

The GPlates Portal: Cloud-Based Interactive 3D Visualization of Global Geophysical and Geological Data in a Web Browser.

Science.gov (United States)

Müller, R Dietmar; Qin, Xiaodong; Sandwell, David T; Dutkiewicz, Adriana; Williams, Simon E; Flament, Nicolas; Maus, Stefan; Seton, Maria

2016-01-01

The pace of scientific discovery is being transformed by the availability of 'big data' and open access, open source software tools. These innovations open up new avenues for how scientists communicate and share data and ideas with each other and with the general public. Here, we describe our efforts to bring to life our studies of the Earth system, both at present day and through deep geological time. The GPlates Portal (portal.gplates.org) is a gateway to a series of virtual globes based on the Cesium Javascript library. The portal allows fast interactive visualization of global geophysical and geological data sets, draped over digital terrain models. The globes use WebGL for hardware-accelerated graphics and are cross-platform and cross-browser compatible with complete camera control. The globes include a visualization of a high-resolution global digital elevation model and the vertical gradient of the global gravity field, highlighting small-scale seafloor fabric such as abyssal hills, fracture zones and seamounts in unprecedented detail. The portal also features globes portraying seafloor geology and a global data set of marine magnetic anomaly identifications. The portal is specifically designed to visualize models of the Earth through geological time. These space-time globes include tectonic reconstructions of the Earth's gravity and magnetic fields, and several models of long-wavelength surface dynamic topography through time, including the interactive plotting of vertical motion histories at selected locations. The globes put the on-the-fly visualization of massive data sets at the fingertips of end-users to stimulate teaching and learning and novel avenues of inquiry.

Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks

Science.gov (United States)

Smeaton, Craig; Austin, William E. N.; Davies, Althea L.; Baltzer, Agnes; Howe, John A.; Baxter, John M.

2017-12-01

Fjords are recognised as hotspots for the burial and long-term storage of carbon (C) and potentially provide a significant climate regulation service over multiple timescales. Understanding the magnitude of marine sedimentary C stores and the processes which govern their development is fundamental to understanding the role of the coastal ocean in the global C cycle. In this study, we use the mid-latitude fjords of Scotland as a natural laboratory to further develop methods to quantify these marine sedimentary C stores on both the individual fjord and national scale. Targeted geophysical and geochemical analysis has allowed the quantification of sedimentary C stocks for a number of mid-latitude fjords and, coupled with upscaling techniques based on fjord classification, has generated the first full national sedimentary C inventory for a fjordic system. The sediments within these mid-latitude fjords hold 640.7 ± 46 Mt of C split between 295.6 ± 52 and 345.1 ± 39 Mt of organic and inorganic C, respectively. When compared, these marine mid-latitude sedimentary C stores are of similar magnitude to their terrestrial equivalents, with the exception of the Scottish peatlands, which hold significantly more C. However, when area-normalised comparisons are made, these mid-latitude fjords are significantly more effective as C stores than their terrestrial counterparts, including Scottish peatlands. The C held within Scotland's coastal marine sediments has been largely overlooked as a significant component of the nation's natural capital; such coastal C stores are likely to be key to understanding and constraining improved global C budgets.

Sea-floor morphology and sedimentary environments in southern Narragansett Bay, Rhode Island

Science.gov (United States)

McMullen, Katherine Y.; Poppe, Lawrence J.; Blackwood, Dann S.; Nardi, Matthew J.; Andring, Matthew A.

2015-09-09

Multibeam echosounder data collected by the National Oceanic and Atmospheric Administration along with sediment samples and still and video photography of the sea floor collected by the U.S. Geological Survey were used to interpret sea-floor features and sedimentary environments in southern Narragansett Bay, Rhode Island, as part of a long-term effort to map the sea floor along the northeastern coast of the United States. Sea-floor features include rocky areas and scour depressions in high-energy environments characterized by erosion or nondeposition, and sand waves and megaripples in environments characterized by coarse-grained bedload transport. Two shipwrecks are also located in the study area. Much of the sea floor is relatively featureless within the resolution of the multibeam data; sedimentary environments in these areas are characterized by processes associated with sorting and reworking. This report releases bathymetric data from the multibeam echosounder, grain-size analyses of sediment samples, and photographs of the sea floor and interpretations of the sea-floor features and sedimentary environments. It provides base maps that can be used for resource management and studies of topics such as benthic ecology, contaminant inventories, and sediment transport.

High resolution reservoir geological modelling using outcrop information

Energy Technology Data Exchange (ETDEWEB)

Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others

1997-08-01

This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

An Overview of Geologic Carbon Sequestration Potential in California

Energy Technology Data Exchange (ETDEWEB)

Cameron Downey; John Clinkenbeard

2005-10-01

As part of the West Coast Regional Carbon Sequestration Partnership (WESTCARB), the California Geological Survey (CGS) conducted an assessment of geologic carbon sequestration potential in California. An inventory of sedimentary basins was screened for preliminary suitability for carbon sequestration. Criteria included porous and permeable strata, seals, and depth sufficient for critical state carbon dioxide (CO{sub 2}) injection. Of 104 basins inventoried, 27 met the criteria for further assessment. Petrophysical and fluid data from oil and gas reservoirs was used to characterize both saline aquifers and hydrocarbon reservoirs. Where available, well log or geophysical information was used to prepare basin-wide maps showing depth-to-basement and gross sand distribution. California's Cenozoic marine basins were determined to possess the most potential for geologic sequestration. These basins contain thick sedimentary sections, multiple saline aquifers and oil and gas reservoirs, widespread shale seals, and significant petrophysical data from oil and gas operations. Potential sequestration areas include the San Joaquin, Sacramento, Ventura, Los Angeles, and Eel River basins, followed by the smaller Salinas, La Honda, Cuyama, Livermore, Orinda, and Sonoma marine basins. California's terrestrial basins are generally too shallow for carbon sequestration. However, the Salton Trough and several smaller basins may offer opportunities for localized carbon sequestration.

Tracing contaminant pathways in sandy heterogeneous glaciofluvial sediments using a sedimentary depositional model

International Nuclear Information System (INIS)

Webb, E.K.; Anderson, M.P.

1990-01-01

Heterogeneous sedimentary deposits present complications for tracking contaminant movement by causing a complex advective flow field. Connected areas of high conductivity produce so-called fast paths that control movement of solutes. Identifying potential fast paths and describing the variation in hydraulic properties was attempted through simulating the deposition of a glaciofluvial deposit (outwash). Glaciofluvial deposits usually consist of several depositional facies, each of which has different physical characteristics, depositional structures and hydraulic properties. Therefore, it is unlikely that the property of stationarity (a constant mean hydraulic conductivity and a mono-modal probability distribution) holds for an entire glaciofluvial sequence. However, the process of dividing an outwash sequence into geologic facies presumably identifies units of material with similar physical characteristics. It is proposed that patterns of geologic facies determined by field observation can be quantified by mathematical simulation of sediment deposition. Subsequently, the simulated sediment distributions can be used to define the distribution of hydrogeologic parameters and locate possible fast paths. To test this hypothesis, a hypothetical glacial outwash deposit based on geologic facies descriptions contained in the literature was simulated using a sedimentary depositional model, SEDSIM, to produce a three-dimensional description of sediment grain size distributions. Grain size distributions were then used to estimate the spatial distribution of hydraulic conductivity. Subsequently a finite-difference flow model and linked particle tracking algorithm were used to trace conservative transport pathways. This represents a first step in describing the spatial heterogeneity of hydrogeologic characteristics for glaciofluvial and other braided stream environments. (Author) (39 refs., 7 figs.)

Niger republic mineral planning ( part two): actual state of Niger republic geological knowledge

International Nuclear Information System (INIS)

Joo, Julien; Franconi, A.

1983-01-01

In this document, the followings points are described: available scientific supports basicly use for mining and geological research; geological history outline of Niger republic and west Africa; crystalline fields of liptako-gourma (western part of Niger); air massif; southern Niger crystalline (Damagaram-Mounio, and southern Maradi); Primary , secondary and tertiary formations of Niger western sedimentary basin and eastern Niger crystalline socle and phanerozoic formation [fr

Main geologic characteristics and metallogenic models of uranium deposits in Zhejiang

International Nuclear Information System (INIS)

Tang Qitao

2000-01-01

Uranium resources in Zhejiang is abundant with numerous mineralization types. According to the genesis they can be classified into: sedimentary-reworking type, hydrothermal type and infiltration type. The author briefly describes main geologic characteristics and metallogenic models of different type uranium deposits

On selection of geological medium for disposal of high-level radwaste

International Nuclear Information System (INIS)

Min Maozhong

1991-01-01

The present paper briefly reviews the suitability of some rocks as geological disposal repositories of high-level radwaste (HLW). The suitable rocks for geological ogi disposal of HLW are rock salt (salt diapir, bedded salt), granite, argillaceous rocks, tuff, basalt, gabbro, diabase, anhydrite, marine sedimentary rocks etc., especially, rock salt, granite, and argillaceous rocks. The data of principal hydraulic properties, mechanical-physical properties for various rocks in typical environment which might be considered for disposal purposes are also given in this paper. These data give a reference to China's geological disposal of HLW in the future

A process-sedimentary framework for characterizing recent and ancient sabkhas

Science.gov (United States)

Handford, C.R.

1981-01-01

The discovery of sabkha environments during the 1960's, marked the beginning of Recent evaporite sedimentological studies and their perception as models for facies analysis. However, variation among Recent sabkhas, though recognized by the geologic community, has not been duly addressed, which has resulted in overuse of the Trucial Coast model in comparative sedimentological studies. Knowledge of the dominant physical processes which determine sabkha morphology, and of the sedimentary response to those processes, can lead to a fundamental understanding of a sabkha's origin and of how it differs from other sabkhas. Physical processes thought to be most important (besides evaporation) include those operative under: (1) marine-; (2) fluvial-lacustrine-; and (3) eolian-dominated conditions. Dominance of one or more of these in the proper settings give rise to marine coastal sabkhas, continental playas, and interdune sabkhas. Sedimentary responses to dominant physical processes lead to the development of sabkhas consisting of a combination of either: (1) terrigenous clastics; (2) carbonate-sulfate (anhydrite-gypsum) minerals; or (3) soluble salts (halite, sylvite, polyhalite, etc.). Sediment characterization can also allow discrimination of the range or compositional variety in, for example, coastal sabkhas. Where applied to the stratigraphic record, this classification system may help unravel the sedimentary history of an ancient sabkha system, and a determination of the dominant physical processes that ruled its development. ?? 1981.

Geology and potential of the formation of sandstone type uranium mineralization at Hatapang region, North Sumatera

International Nuclear Information System (INIS)

Ngadenin

2013-01-01

The Study based on geological setting of Hatapang region, North Sumatera, identified as a favourable area to the formation of sandstone type uranium mineralization. This characterized by the occurred of anomalous radioactivity, uranium contents of the upper cretaceous granite intrusions and radioactivity anomalous of tertiary sedimentary rocks deposited in terrestrial environments. The study is objective to find out the potential formation of sandstone type-uranium mineralization within tertiary sedimentary rocks based on data’s studies of geological, geochemical, mineralogy, radioactivity of rocks. Stratigraphy of Hatapang area of the oldest to youngest are quartz units (permian-carboniferous), sandstone units (upper Triassic), granite (upper cretaceous), conglomerate units (Lower –middle Miocene) and tuff units (Pleistocene). Hatapang’s granite is S type granite which is not only potential as source of radioactive minerals, particularly placer type monazite, but also potential as source rocks of sandstone type-uranium mineralization on lighter sedimentary rocks. Sedimentary rock of conglomerate units has potential as host rock, even though uranium did not accumulated in its rocks since the lack number of carbon as precipitant material and dissolved U"+"6 in water did not reduced into U"+"4 caused the uranium mineralization did not deposited. (author)

The GPlates Portal: Cloud-Based Interactive 3D Visualization of Global Geophysical and Geological Data in a Web Browser.

Directory of Open Access Journals (Sweden)

R Dietmar Müller

Full Text Available The pace of scientific discovery is being transformed by the availability of 'big data' and open access, open source software tools. These innovations open up new avenues for how scientists communicate and share data and ideas with each other and with the general public. Here, we describe our efforts to bring to life our studies of the Earth system, both at present day and through deep geological time. The GPlates Portal (portal.gplates.org is a gateway to a series of virtual globes based on the Cesium Javascript library. The portal allows fast interactive visualization of global geophysical and geological data sets, draped over digital terrain models. The globes use WebGL for hardware-accelerated graphics and are cross-platform and cross-browser compatible with complete camera control. The globes include a visualization of a high-resolution global digital elevation model and the vertical gradient of the global gravity field, highlighting small-scale seafloor fabric such as abyssal hills, fracture zones and seamounts in unprecedented detail. The portal also features globes portraying seafloor geology and a global data set of marine magnetic anomaly identifications. The portal is specifically designed to visualize models of the Earth through geological time. These space-time globes include tectonic reconstructions of the Earth's gravity and magnetic fields, and several models of long-wavelength surface dynamic topography through time, including the interactive plotting of vertical motion histories at selected locations. The globes put the on-the-fly visualization of massive data sets at the fingertips of end-users to stimulate teaching and learning and novel avenues of inquiry.

Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks

Directory of Open Access Journals (Sweden)

C. Smeaton

2017-12-01

Full Text Available Fjords are recognised as hotspots for the burial and long-term storage of carbon (C and potentially provide a significant climate regulation service over multiple timescales. Understanding the magnitude of marine sedimentary C stores and the processes which govern their development is fundamental to understanding the role of the coastal ocean in the global C cycle. In this study, we use the mid-latitude fjords of Scotland as a natural laboratory to further develop methods to quantify these marine sedimentary C stores on both the individual fjord and national scale. Targeted geophysical and geochemical analysis has allowed the quantification of sedimentary C stocks for a number of mid-latitude fjords and, coupled with upscaling techniques based on fjord classification, has generated the first full national sedimentary C inventory for a fjordic system. The sediments within these mid-latitude fjords hold 640.7 ± 46 Mt of C split between 295.6 ± 52 and 345.1 ± 39 Mt of organic and inorganic C, respectively. When compared, these marine mid-latitude sedimentary C stores are of similar magnitude to their terrestrial equivalents, with the exception of the Scottish peatlands, which hold significantly more C. However, when area-normalised comparisons are made, these mid-latitude fjords are significantly more effective as C stores than their terrestrial counterparts, including Scottish peatlands. The C held within Scotland's coastal marine sediments has been largely overlooked as a significant component of the nation's natural capital; such coastal C stores are likely to be key to understanding and constraining improved global C budgets.

Generalized surficial geologic map of the Fort Irwin area, San Bernadino: Chapter B in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

Science.gov (United States)

Miller, David M.; Menges, Christopher M.; Lidke, David J.; Buesch, David C.

2014-01-01

The geology and landscape of the Fort Irwin area, typical of many parts of the Mojave Desert, consist of rugged mountains separated by broad alluviated valleys that form the main coarse-resolution features of the geologic map. Crystalline and sedimentary rocks, Mesozoic and older in age, form most of the mountains with lesser accumulations of Miocene sedimentary and volcanic rocks. In detail, the area exhibits a fairly complex distribution of surficial deposits resulting from diverse rock sources and geomorphology that has been driven by topographic changes caused by recent and active faulting. Depositional environments span those typical of the Mojave Desert: alluvial fans on broad piedmonts, major intermittent streams along valley floors, eolian sand dunes and sheets, and playas in closed valleys that lack through-going washes. Erosional environments include rocky mountains, smooth gently sloping pediments, and badlands in readily eroded sediment. All parts of the landscape, from regional distribution of mountains, valleys, and faults to details of degree of soil development in surface materials, are portrayed by the surficial geologic map. Many of these attributes govern infiltration and recharge, and the surface distribution of permeable rock units such as Miocene sedimentary and volcanic rocks provides a basis for evaluating potential groundwater storage. Quaternary faults are widespread in the Fort Irwin area and include sinistral, east-striking faults that characterize the central swath of the area and the contrasting dextral, northwest-striking faults that border the east and west margins. Bedrock distribution and thickness of valley-fill deposits are controlled by modern and past faulting, and faults on the map help to identify targets for groundwater exploration.

Capture and geological sequestration of CO2: fighting against global warming

International Nuclear Information System (INIS)

Czernichowski-Lauriol, I.

2006-01-01

In order to take up the global warming challenge, a set of emergency measures is to be implemented: energy saving, clean transportation systems, development of renewable energy sources.. CO 2 sequestration of massive industrial emission sources inside deep geologic formations is another promising solution, which can contribute to the division by two of the world CO 2 emissions between today and 2050. The CO 2 capture and sequestration industry is developing. Research projects and pilot facilities are on the increase over the world. Their aim is to warrant the efficiency and security of this technology over the centuries to come. (J.S.)

Geological characteristics of granite type uranium deposits in middle of Inner Mongolia in comparison with south China

International Nuclear Information System (INIS)

Wang Gui

2012-01-01

Granites extensively distributed in middle of Inner Mongolia and South China, namely Caledonian, Hercynian and Yanshanian. Some of the intrusive are composed of granites which belong to different ages. Some of the uranium deposits were found inside the granite bodies or in sedimentary rocks and meta sedimentary rocks along the exocontact zone. Granite rock was comparing in middle Inner Mongolia and South China, including Uranium ore-forming geological conditions. ore-forming process and Ore-controlling factors. Think the Uranium ore-forming geological conditions is similar; ore-forming process is mainly for low-mid temperature hot liquid; Uranium ore bodies (uranium mineralization) was controlled by fracture. Explain granite type uranium mineralization potential is tremendous in middle of Inner Mongolia. (author)

Presumption of the distribution of the geological structure based on the geological survey and the topographic data in and around the Horonobe area

International Nuclear Information System (INIS)

Sakai, Toshihiro; Matsuoka, Toshiyuki

2015-06-01

The Horonobe Underground Research Laboratory (URL) Project, a comprehensive research project investigating the deep underground environment in sedimentary rock, is being pursued by the Japan Atomic Energy Agency (JAEA) at Horonobe-cho in Northern Hokkaido, Japan. One of the main goals of the URL project is to establish techniques for investigation, analysis and assessment of the deep geological environment. JAEA constructed the geologic map and the database of geological mapping in Horonobe-cho in 2005 based on the existing literatures and 1/200,000 geologic maps published by Geological Survey of Japan, and then updated the geologic map in 2007 based on the results of various investigations which were conducted around the URL as the surface based investigation phase of the URL project. On the other hand, there are many geological survey data which are derived from natural resources (petroleum, natural gas and coal, etc.) exploration in and around Horonobe-cho. In this report, we update the geologic map and the database of the geological mapping based on these geological survey and topographical analysis data in and around the Horonobe area, and construct a digital geologic map and a digital database of geological mapping as GIS. These data can be expected to improve the precision of modeling and analyzing of geological environment including its long-term evaluation. The digital data is attached on CD-ROM. (J.P.N.)

Measurement of unsaturated hydraulic properties and evaluation of property-transfer models for deep sedimentary interbeds, Idaho National Laboratory, Idaho

Science.gov (United States)

Perkins, Kimberlie; Johnson, Brittany D.; Mirus, Benjamin B.

2014-01-01

Operations at the Idaho National Laboratory (INL) have the potential to contaminate the underlying Eastern Snake River Plain (ESRP) aquifer. Methods to quantitatively characterize unsaturated flow and recharge to the ESRP aquifer are needed to inform water-resources management decisions at INL. In particular, hydraulic properties are needed to parameterize distributed hydrologic models of unsaturated flow and transport at INL, but these properties are often difficult and costly to obtain for large areas. The unsaturated zone overlying the ESRP aquifer consists of alternating sequences of thick fractured volcanic rocks that can rapidly transmit water flow and thinner sedimentary interbeds that transmit water much more slowly. Consequently, the sedimentary interbeds are of considerable interest because they primarily restrict the vertical movement of water through the unsaturated zone. Previous efforts by the U.S. Geological Survey (USGS) have included extensive laboratory characterization of the sedimentary interbeds and regression analyses to develop property-transfer models, which relate readily available physical properties of the sedimentary interbeds (bulk density, median particle diameter, and uniformity coefficient) to water retention and unsaturated hydraulic conductivity curves.

Fluvial systems and their sedimentary models

Directory of Open Access Journals (Sweden)

Dragomir Skabeme

1995-12-01

Full Text Available The Slovenian géomorphologie and sedimentologie terminology for fluvial depositional environments is not established yet. Therefore a classification and the proposal for Slovenian names of fluvial sedimentary and erosional forms and influences controlling them are discussed. Attention is given to the problems of recognition of sedimentary environments in sedimentary rocks, and to fluvial sedimentary models.

Geology and mineral potential of Ethiopia: a note on geology and mineral map of Ethiopia

Energy Technology Data Exchange (ETDEWEB)

Tadesse, S.; Milesi, J.P.; Deschamps, Y. [University of Addis Ababa, Addis Ababa (Ethiopia). Dept. for Geology & Geophysics

2003-05-01

This work presents a geoscientific map and database for geology, mineral and energy resources of Ethiopia in a digital form at a scale of 1 : 2,000,000, compiled from several sources. The final result of the work has been recorded on CD-ROM in GIS format. Metallic resources (precious, rare, base and ferrous-ferroalloy metals) are widely related to the metamorphic meta-volcano-sedimentary belts and associated intrusives belonging to various terranes of the Arabian-Nubian Shield, accreted during the East and West Gondwana collision (Neoproterozoic, 900-500 Ma). Industrial minerals and rock resources occur in more diversified geological environments, including the Proterozoic basement rocks, the Late Paleozoic to Mesozoic sediments and recent (Cenozoic) volcanics and associated sediments. Energy resources (oil, coal, geothermal resources) are restricted to Phanerozoic basin sediments and Cenozoic volcanism and rifting areas.

Provenance of Neoproterozoic to upper Cretaceous sedimentary rocks, eastern Greenland: Implications for recognizing the sources of sediments in the Norwegian Sea

Czech Academy of Sciences Publication Activity Database

Sláma, Jiří; Walderhaug, O.; Fonneland, H.; Kosler, J.; Pederson, R. B.

2011-01-01

Roč. 238, 3/4 (2011), s. 254-267 ISSN 0037-0738 Institutional research plan: CEZ:AV0Z30130516 Keywords : sedimentary * Eastern Greenland * provenance * U-Pb and Lu-Hf * zircon * Jan Mayen Island * North Atlantic Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.537, year: 2011

Physicomechanical parameters of sedimentary rocks in eastern Sichuan, China

International Nuclear Information System (INIS)

Guo, Jian; Sun, Yan; Shu, Liangshu; Zhu, Wenbin; Wang, Feng; Li, Benliang; Liu, Deliang

2009-01-01

Rock samples were collected and selected from the sedimentary covering strata from Cambrian to Jurassic in eastern Sichuan, China, which belongs to the Upper Yangtze plate. Physicomechanical parameters were measured systematically. Based on parametric texture characteristics and observation data of geology, five regional layer-slip systems are derived. The five layer-slip systems correspond to five reservoir–cover systems, as the incompetent beds correspond to cover beds and the competent beds to reservoir beds. In comparison with the Middle and Lower Yangtze plates, the physicomechanical parameters, lithologic composition and structural characteristics are basically similar to the Upper Yangtze plate. This comparison offers some insight into the oil and gas reservoir–cover systems in the region

Hydrogeology of exogenic epigenic uranium deposits (sedimentary type) in Uzbekistan

International Nuclear Information System (INIS)

Irgashev, Yu.I.; Gavrilov, V.A.; Muslimov, B.A.

1996-01-01

Common problems of hydrogeology and geotechnology for uranium deposits (sedimentary type) in the Republic of Uzbekistan are discussed in the paper. Hydrogeology includes studies of texture of water-bearing horizons, occurrences of ore bodies in horizons, hydrochemical survey, hydrodynamics and engineering geology. Features of deposits workable by underground leaching are presented. Such terms as 'water-bearing horizon', 'efficiency', 'water-bearing bed' are explained accounting the results of 30 year investigations conducted during prospecting, designing and exploitation of uranium deposits. Stages of hydrogeological survey are listed and features of each of them are described. Importance of geotechnology for a deposit characterization is shown. (author). 6 refs.; 1 fig.; 1 tab

Age, sedimentary environments, and other aspects of sandstone and related host rocks for uranium deposits

International Nuclear Information System (INIS)

1983-01-01

Project II of the Uranium Geology Working Group was assigned to the study of sedimentary basins and sandstone - type uranium deposits. About 40% of the worlds's uranium resources are contained in sandstone-type deposits, which has led to extensive research. The research was carried out mainly by correspondence, and the results reported by 21 geologists from 10 nations are summarized in this report. It investigated five topics dealing with important aspects of the geology of uranium ores in sandstone host formations: age of host rock; partitioning of uranium between continental and marine sediments; latitude limitation on formation of sandstone deposits; effect of rock formation dip on sandstone ores; usefulness of stable isotope and fluid inclusion studies. The results of studies on these subjects form part of a wider programme of the Working Group, whose final results will be presented at the 27th International Geological Congress in Moscow in 1984

Geology and genesis of uranium deposits in sedimentary and metamorphic formation

International Nuclear Information System (INIS)

Danchev, V.I.; Belevtsev, Ya.N.

1980-01-01

Main genetic types of uranium deposits in sedimentary cover are described. Their genetic classification is based on the principle of conjugation of ore-forming process with the stages of lithogenesis of ore-enclosing rocks. Examples of poligeneity of uranium mineralization are presented. Texture-structural peculiarities of ores and types of ore-controlling zonality are considered as criteria of definite deposits belonging to various genetic classes. The analysis is given of main regularities of location of exogenous and poligenic uranium deposits. Processes of uranium ore-formation under the conditions of low and high degrees of metamorphism are considered. On the basis of separate types of deposits shown is the possibility of mobilization, transfer and concentration of ore substance, its transformation from primary to secondary forms. Metamorphous and ultrametamorphous deposits are formed as a result of ore element translocation within considerable distances under the effect of endogenous solutions and their concentration in favourable structures. Conclusions on the effect of lithogenesis and metamorphism processes on the ore formation are substantiated by field observations, analyses (including methods of isotopic geochemistry) as well as by experiments

Discussion on the origin of sedimentary rock resistivity

International Nuclear Information System (INIS)

Dong Gangjian

2012-01-01

Conduction current way of sedimentary rock sedimentary rock is caused by the internal structure of sedimentary rock sedimentary rock pore resistance depends on the salinity of pore water and clay content and distribution. Resistivity of sedimentary rock sedimentary rock major factor in mineral composition, water resistance, oil resistance. and sedimentary structures. In practice, we should give full attention to the difference between lithology and physical properties. (author)

Potential uses of genetic geological modelling to identify new uranium provinces

International Nuclear Information System (INIS)

Finch, W.I.

1982-01-01

Genetic-geological modelling is the placing of the various processes of the development of a uranium province into distinct stages that are ordered chronologically and made part of a matrix with corresponding geologic evidence. The models can be applied to a given region by using one of several methods to determine a numerical favorability rating. Two of the possible methods, geologic decision analysis and an oil-and-gas type of play analysis, are briefly described. Simplified genetic models are given for environments of the quartz-pebble conglomerate, unconformity-related vein, and sandstone types of deposits. Comparison of the genetic models of these three sedimentary-related environments reveals several common attributes that may define a general uranium province environment

Geochemistry of shale and sedimentary pyrite as a proxy for gold fertility in the Selwyn basin area, Yukon

Science.gov (United States)

Sack, Patrick J.; Large, Ross R.; Gregory, Daniel D.

2018-01-01

Selwyn basin area strata contain sedimentary pyrite with Au above background levels when analyzed by laser ablation-inductively coupled mass spectrometry. Hyland Group rocks contain framboidal pyrite contents of 670 ppb Au, 1223 ppm As, and 5.3 ppm Te; the mean of all types of sedimentary pyrite in the Hyland Group is 391 ppb Au, 1489 ppm As, and 3.8 ppm Te. These levels are similar to sedimentary pyrite in host lithologies from major orogenic gold districts in New Zealand and Australia. Comparison of whole rock and pyrite data show that rocks deposited in continental slope settings with significant terrigenous input contain pyrite that is consistently enriched in Au, As, Te, Co, and Cu. Although data are limited, whole rock samples of stratigraphic units containing Au-rich pyrite also contain high Au, indicating that most of the Au is within sedimentary pyrite. Based on geologic characteristics and comparison of pyrite chemistry data with whole rock chemistry, Selwyn basin area strata have the necessary ingredients to form orogenic gold deposits: Au-enriched source rocks, metamorphic conditions permissive of forming a metamorphic ore fluid, and abundant structural preparation for channeling fluids and depositing ore.

Petroleum geology of the Palo Duro Basin, Texas Panhandle

International Nuclear Information System (INIS)

Rose, P.R.

1986-03-01

The Palo Duro Basin, Permian Basin, Texas is an asymmetric, relatively shallow, intracratonic basin in the southern Texas Panhandle filled mostly by Mississippian, Pennsylvanian, and Permian sedimentary rocks. Although deeper and prolific prolific petroleum-producing basins adjoin it on the north (Anadarko Basin), south (Midland Basin), and east (Hardeman Basin), the Palo Duro Basin has produced remarkably small amounts of oil and gas to date. This is all the more noteworthy because the sedimentary sequence and rock types of the basin are similar to those of the adjacent basins. Analyses of the stratigraphic succession and structural configuration of the Palo Duro Basin suggest that adequate reservoir rocks, top-seals, and geologic structures are present. Most of the structures formed early enough to have trapped hydrocarbons if they were migrating in the rock column. Although additional work is under way to properly address the question of the petroleum source rocks, generation, and migration, the general absence of production in the basin may relate to an overall deficiency in hydrocarbon generation within the basin. Geologic information in this report will form part of the basis for further analysis and conclusions on hydrocarbon potential in the Palo Duro Basin

Deformation style of the Mesozoic sedimentary rocks in southern Thailand

Science.gov (United States)

Kanjanapayont, Pitsanupong

2014-10-01

Mesozoic sedimentary rocks in southern Thailand are widespread from NNE-SSW and N-S in Chumphon and Trang provinces. The Mesozoic stratigraphic units are the marine Triassic Sai Bon Formation and the non-marine Jurassic-Cretaceous Thung Yai Group, the latter subdivided into Khlong Min, Lam Thap, Sam Chom, and Phun Phin Formations. These units overlie Permian carbonate rocks with an angular unconformity, and are overlain unconformably by Cenozoic units and the Quaternary sediments. The Mesozoic rocks have been folded to form two huge first-ordered syncline or synclinoria, the Chumphon and Surat Thani-Krabi-Trang synclinoria. These synclinoria are elongated in NNE-SSW to N-S direction, and incorporate asymmetric lower-order parasitic folds. The folds have moderately to steeply dipping eastward limbs and more gently dipping westward limbs. These folds were transected by brittle fractures in four major directions. These geologic structures indicate WNW-ESE to E-W contraction with top-to-the-east simple shear at some time before the deposition of the Cenozoic sedimentary units. No major deformation has affected the rocks subsequently, apart from the formation of the fault-controlled Cenozoic basins.

U.S. Geological Survey assessment of global potash production and resources—A significant advancement for global development and a sustainable future.

Science.gov (United States)

Cocker, Mark D.; Orris, Greta J.; Wynn, Jeff

2016-01-01

During the past 15 yr, the global requirement for fertilizers has grown considerably, mainly due to demand by a larger and wealthier world population for more and higher-quality food. The demand and price for potash as a primary fertilizer ingredient have increased in tandem, because of the necessity to increase the quantity and quality of food production on the decreasing amount of available arable land. The primary sources of potash are evaporates, which occur mainly in marine salt basins and a few brine-bearing continental basins. World potash resources are large, but distribution is inequitable and not presently developed in countries where population and food requirements are large and increasing. There is no known substitute for potash in fertilizer, so knowledge of the world’s potash resources is critical for a sustainable future. The U.S. Geological Survey recently completed a global assessment of evaporite-hosted potash resources, which included a geographic information system–based inventory of known potash resources. This assessment included permissive areas or tracts for undiscovered resources at a scale of 1:1,000,000. Assessments of undiscovered potash resources were conducted for a number of the world’s evaporite-hosted potash basins. The data collected provide a major advance in our knowledge of global potash resources that did not exist prior to this study. The two databases include: (1) potash deposits and occurrences, and (2) potash tracts (basins that contain these deposits and occurrences and potentially undiscovered potash deposits). Data available include geology, mineralogy, grade, tonnage, depth, thickness, areal extent, and structure, as well as numerous pertinent references.

Deep geological disposal of radioactive waste - An international perspective

Energy Technology Data Exchange (ETDEWEB)

Gautschi, A. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland)

2015-07-01

This article provides a condensed summary of a presentation given by the author in June 2015. Various types of disposal facilities are reviewed, ranging from very limited natural barriers through to sophisticated, multi-barrier systems. Advantages, disadvantages and costs of the various disposal options are discussed. In particular, solutions used worldwide are listed in a comprehensive table. The simpler solutions range from open, non-engineered barriers through to simple geological barriers on the surface and underground. Multi-barrier systems in Sweden, Finland, France, Switzerland and Canada are listed and discussed. These include geological barriers through to engineered confinements in crystalline and sedimentary rocks. Links to relevant internet web sites are quoted.

Deep geological disposal of radioactive waste - An international perspective

International Nuclear Information System (INIS)

Gautschi, A.

2015-01-01

This article provides a condensed summary of a presentation given by the author in June 2015. Various types of disposal facilities are reviewed, ranging from very limited natural barriers through to sophisticated, multi-barrier systems. Advantages, disadvantages and costs of the various disposal options are discussed. In particular, solutions used worldwide are listed in a comprehensive table. The simpler solutions range from open, non-engineered barriers through to simple geological barriers on the surface and underground. Multi-barrier systems in Sweden, Finland, France, Switzerland and Canada are listed and discussed. These include geological barriers through to engineered confinements in crystalline and sedimentary rocks. Links to relevant internet web sites are quoted

Geologic map of the Lower Valley quadrangle, Caribou County, Idaho

Science.gov (United States)

Oberlindacher, H. Peter; Hovland, R. David; Miller, Susan T.; Evans, James G.; Miller, Robert J.

2018-04-05

The Lower Valley 7.5-minute quadrangle, located in the core of the Southeast Idaho Phosphate Resource Area, includes Mississippian to Triassic marine sedimentary rocks, Pliocene to Pleistocene basalt, and Tertiary to Holocene surficial deposits. The Mississippian to Triassic marine sedimentary sequence was deposited on a shallow shelf between an emergent craton to the east and the Antler orogenic belt to the west. The Meade Peak Phosphatic Shale Member of the Permian Phosphoria Formation hosts high-grade deposits of phosphate that were the subject of geologic studies through much of the 20th century. Open-pit mining of the phosphate has been underway within and near the Lower Valley quadrangle for several decades.

Engineering geology and environmental protection

Energy Technology Data Exchange (ETDEWEB)

Sergeev, E M

1979-01-01

A classification is made of the anthropogenic processes in the environment into global, local, universally distributed, zonal, regional, and essentially local processes. Engineering geology is defined as the principal science concerned with the study of the geological medium which in turn involves the study of fossil fuel geology. 22 references.

The geologic history of Margaritifer basin, Mars

Science.gov (United States)

Salvatore, M. R.; Kraft, M. D.; Edwards, Christopher; Christensen, P.R.

2016-01-01

In this study, we investigate the fluvial, sedimentary, and volcanic history of Margaritifer basin and the Uzboi-Ladon-Morava (ULM) outflow channel system. This network of valleys and basins spans more than 8000 km in length, linking the fluvially dissected southern highlands and Argyre Basin with the northern lowlands via Ares Vallis. Compositionally, thermophysically, and morphologically distinct geologic units are identified and are used to place critical relative stratigraphic constraints on the timing of geologic processes in Margaritifer basin. Our analyses show that fluvial activity was separated in time by significant episodes of geologic activity, including the widespread volcanic resurfacing of Margaritifer basin and the formation of chaos terrain. The most recent fluvial activity within Margaritifer basin appears to terminate at a region of chaos terrain, suggesting possible communication between surface and subsurface water reservoirs. We conclude with a discussion of the implications of these observations on our current knowledge of Martian hydrologic evolution in this important region.

The sedimentary record and petrophysical logs from the Spanish Central Pyrenees: Implications for paleoclimate change in the Early Devonian

Czech Academy of Sciences Publication Activity Database

Slavík, Ladislav; Valenzuela-Ríos, J. I.; Hladil, Jindřich; Chadimová, Leona; Liao, J-Ch.; Hušková, Aneta; Calvo, H.; Hrstka, Tomáš

2015-01-01

Roč. 21, - (2015), s. 350-350 ISSN 1608-8166. [International Congress on Stratigraphy /2./. STRATI 2015. 19.07.2015-23.07.2015, Graz] Institutional support: RVO:67985831 Keywords : stratigraphy * Early Devonian * sedimentary record * paleoclimate change * Spanish Central Pyrenees Subject RIV: DB - Geology ; Mineralogy http://www.zobodat.at/pdf/Ber-Inst-Erdwiss-Univ-Graz_21_0001-0437.pdf

Stratigraphic position, origin and characteristics of manganese mineralization horizons in the Late Cretaceous volcano-sedimentary sequence, south-southwest of Sabzevar

Directory of Open Access Journals (Sweden)

Sajjad Maghfouri

2014-10-01

part or LMV unit comprised of limestone, marl and volcanic rocks, overlies concordantly on the lower part (K2tv. The manganese mineralization within the host volcano-sedimentary sequence, based on stratigraphic position, relative age and type of host rocks involved the two horizons: the first horizon (Mn Ia, Ib consisting of Benesbourd (Masoudi, 2008, Nudeh (Nasrolahi et al., 2012, Homaie (Nasiri et al., 2010, Goft and Manganese Gostar Khavar Zamin deposits, occurred in the lower part of the sequence (K2tv unit and is hosted by red tuffs. The second horizon (Mn II comprising of Zakeri (Taghizadeh et al., 2012, Cheshmeh Safeid, Mohammad Abad Oryan and Chah Setareh deposits, is hosted by marly-carbonate tuffs and locates within the upper part of the sequence (LMV unit (Maghfouri, 2012. Geometry and shape of the ore bodies in various deposits are as stratiform, layered, parallel and concordant with layering of the host rocks. Textures of the ores include massive, lenticular, banded, laminated and disseminated. Mineralogy of the ores in the two ore horizons is simple and similar and is dominated by pyrolusite, psilomelane and braunite. Gangue minerals are predominantly the host rock-forming minerals including quartz, chlorite and feldspar. Discussion Geochemical data, structures and textures, stratigraphic position and lithologic characteristics of the host rocks represent that manganese reserves in south-southwest Sabzevar were formed as sedimentary-exhalative. Acknowledgements The authors are grateful to the Tarbiat Modares University Grant Commission for research funding. References Maghfouri, S., 2012. Geology, Mineralogy, Geochemistry and Genesis of Cu Mineralization within Late Cretaceous Volcano-Sedimentary Sequence in Southwest of Sabzevar, with emphasis on the Nudeh Deposit. M.Sc. Thesis, Tarbiat Modares University, Tehran, Iran, 312 pp. (in Persian Masoudi, M., 2008. Geology, mineralogy, geochemistry and genesis of Benesbourd Mn deposit in the Southwest Sabzevar

The relation between well spacing and Net Present Value in fluvial Hot Sedimentary Aquifer geothermal doublets : a West Netherlands Basin case study

NARCIS (Netherlands)

Willems, C.J.L.; Goense, T.; Maghami Nick, Hamidreza M.; Bruhn, D.F.

2016-01-01

This paper analyzes the relation between well spacing and Net Present Value of a Hot Sedimentary Aquifer geothermal doublet. First, a sensitivity analysis is carried out to evaluate the effect of uncertainty of geological and production parameters on the Net present Value. Second a finite-element

Application of /sup 14/C-dating to sedimentary geology and climatology: Sea-level and climate change during the Holocene

Energy Technology Data Exchange (ETDEWEB)

Nakai, Nobuyuki; Ohishi, Shyoji; Kuriyama, Toyoko; Nakamura, Toshio

1987-11-01

AMS /sup 14/C dating of small sized fossil shells, wood chips and sedimentary humic matter has been applied to the investigation of paleoclimatic and sea-level changes in the Holocene, using three estuarine and brackish lake sediment cores, drilled in Kawasaki city and Lake Hamanako, Japan. Precise and detailed ages at differing depths clarified large transitions of Holocene sedimentation rates, of two orders of magnitude. The vertical variation in delta/sup 13/C and C/N results for sedimentary organic matter, combined with AMS /sup 14/C ages, established continous climatic and sea-level fluctuation patterns through time and indicated the existence of neoglaciation coincident with the marine regression at 7500 to 7000 yr BP.

Geological factors of the isotopic distribution of carbon of organic matter in sedimentary rocks

International Nuclear Information System (INIS)

Maass, J.

1981-01-01

The isotope ratio of carbon of fossile organic matter can be regarded as a definite criterion of its genetic origin. As the biofacial character of organic matter, especially the chemical composition (H/C-ratio), decisively influences the mode and quantity of the potential hydrocarbon production, isotopic analysis is an essential method for the prognostic evaluation of sedimentary basins with regard to their oil and gas perspectives. The genetic relations to the parent substance continue in the bituminization and coalification products and make it possible to apply the isotopic analysis of carbon to prospection work for hydrocarbons. (author)

The GPlates Portal: Cloud-based interactive 3D and 4D visualization of global geological and geophysical data and models in a browser

Science.gov (United States)

Müller, Dietmar; Qin, Xiaodong; Sandwell, David; Dutkiewicz, Adriana; Williams, Simon; Flament, Nicolas; Maus, Stefan; Seton, Maria

2017-04-01

The pace of scientific discovery is being transformed by the availability of 'big data' and open access, open source software tools. These innovations open up new avenues for how scientists communicate and share data and ideas with each other, and with the general public. Here, we describe our efforts to bring to life our studies of the Earth system, both at present day and through deep geological time. The GPlates Portal (portal.gplates.org) is a gateway to a series of virtual globes based on the Cesium Javascript library. The portal allows fast interactive visualization of global geophysical and geological data sets, draped over digital terrain models. The globes use WebGL for hardware-accelerated graphics and are cross-platform and cross-browser compatible with complete camera control. The globes include a visualization of a high-resolution global digital elevation model and the vertical gradient of the global gravity field, highlighting small-scale seafloor fabric such as abyssal hills, fracture zones and seamounts in unprecedented detail. The portal also features globes portraying seafloor geology and a global data set of marine magnetic anomaly identifications. The portal is specifically designed to visualize models of the Earth through geological time. These space-time globes include tectonic reconstructions of the Earth's gravity and magnetic fields, and several models of long-wavelength surface dynamic topography through time, including the interactive plotting of vertical motion histories at selected locations. The portal has been visited over half a million times since its inception in October 2015, as tracked by google analytics, and the globes have been featured in numerous media articles around the world. This demonstrates the high demand for fast visualization of global spatial big data, both for the present-day as well as through geological time. The globes put the on-the-fly visualization of massive data sets at the fingertips of end-users to

Sc, Y, La-Lu. Rare earth elements. Vol. A 6a. Y, La, and the lanthanoids. Geochemistry: Sedimentary cycle. Metamorphic cycle. 8. rev. ed

Energy Technology Data Exchange (ETDEWEB)

Ditz, R; Sarbas, B; Schubert, P; Toepper, W

1988-01-01

The present volume 'Rare Earth Elements' A 6a describes origin, mode of occurrence, and behavior of Y and RE elements in the sedimentary and metamorphic cycles, and completes the series of volumes describing cosmo- and geochemistry of these elements. In the chapter 'Sedimentary Cycle', the behavior of Y and RE during the weathering process is first outlined under both marine and terrestrial conditions, including a short compilation for migration and precipitation in surficial weathering and oxidation zones. The main part of the chapter treats, in addition to the mode of occurrence, predominantly the distribution of Y and RE in the different types of sedimentary rocks in relation to genetic processes (comprising physical and/or spatial factors such as geological age of the deposition). A concluding part gives a description of mobilization, migration, and precipitation of Y and RE during the diagenetic transformation of sediments, especially in relation to the various types of ferromanganese concretions. In the chapter 'Metamorphic Cycle', the first, extensive part gives examples of mode of occurrence and behavior of Y and RE during both the contact-metamorphic and prograde and retrograde regional-metamorphic processes affecting sedimentary and igeneous source rocks. The second part briefly describes behaviour of Y and RE during ultrametamorphism of metamorphic rocks, and during metamorphic processes in connection with special types of geologic events (as, e.g., subduction of crustal material into the earth's mantle and impact of extraterrestrial material). (orig.) With 4 figs.

Revisiting the effects of hydrodynamic sorting and sedimentary recycling on chemical weathering indices

Science.gov (United States)

Guo, Yulong; Yang, Shouye; Su, Ni; Li, Chao; Yin, Ping; Wang, Zhongbo

2018-04-01

Although the proxies based on elemental geochemistry of siliciclastic sediments have been well developed to indicate the intensity of chemical weathering in various catchments, their geological indications and limitations, and especially how the differentiation of minerals and sediment grain size influences the applications of these proxies needs more clarification. This paper investigates the interactive effects of weathering, hydraulic sorting and sedimentary recycling on river sediment chemistry, and further validates the application of various weathering indices by measuring mineralogical and geochemical compositions of bank sediments and suspended particulate matters (SPMs) from five rivers in East China bearing various sizes, geologic settings and climatic regimes. For a specific river, the silicate weathering intensity registered in the fine SPMs is systematically stronger than that in the coarse-grained bank sediments. Most of the weathering indices not only reflect the integrated weathering history of various catchments but also depend on hydraulic sorting effect during sediment transport and depositional processes. The correlation between CIA (chemical index of alteration) and WIP (weathering index of Parker) offers an approach to predict the weathering trends of the fine SPMs, coarse bank sediments and recycled sediments under the influence of quartz dilution. To minimize the effects of hydrodynamic sorting and sedimentary recycling, we suggest that the fine sediments (e.g. SPMs and <2 μm fraction of bank sediments) in rivers can better reflect the average of present-day weathering crust in catchments and the weathered terrigenous materials into marginal seas and oceans.

GEOLOGICAL-GEOPHYSICAL EXPLORATION OF THE BAUXITE DEPOSITS APPLICATION OF THE SHALLOW SEIZMIC REFLECTION METHOD

OpenAIRE

Ivan Dragičević; Miroslav Andrić; Ivan Blašković

1991-01-01

The exploration of bauxite deposits in the region of the carbonaceous Dinarides has been performed by using different geological and geophysical methods. Deposits laying shallower or deeper below the roof sediments have so far most often been discovered by expensive drilling methods in a corresponding grid. Complex geological explorations have led to a series of valuable data thus enabling the application of other much more economical methods as well. In the region of the bauxite sedimentary ...

Radioactive waste disposal in deep geologic deposits. Associated research problems

International Nuclear Information System (INIS)

Rousset, G.

1992-01-01

This paper describes the research associated problems for radioactive waste disposal in deep geologic deposits such granites, clays or salt deposits. After a brief description of the underground disposal, the author studies the rheology of sedimentary media and proposes rheological models applied to radioactive wastes repositories. Waste-rock interactions, particularly thermal effects and temperature distribution versus time. 17 refs., 14 figs

Dust – A geology-orientated attempt to reappraise the natural components, amounts, inputs to sediment, and importance for correlation purposes

Czech Academy of Sciences Publication Activity Database

Hladil, Jindřich; Čejchan, Petr; Bábek, O.; Koptíková, Leona; Navrátil, Tomáš; Kubínová, Petra

2010-01-01

Roč. 13, č. 4 (2010), s. 367-384 ISSN 1374-8505 R&D Projects: GA AV ČR IAAX00130702 Institutional research plan: CEZ:AV0Z30130516 Keywords : natural dust * particulare matter * aerosol * sedimentary background * sedimentary inputs * dust teleconnection * limestones * iron contents * Holocene Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.645, year: 2010 http://popups.ulg.ac.be/Geol/docannexe.php?id=3104

The Spatial Thinking Workbook: A Research-Validated Spatial Skills Curriculum for Geology Majors

Science.gov (United States)

Ormand, Carol J.; Shipley, Thomas F.; Tikoff, Basil; Dutrow, Barbara; Goodwin, Laurel B.; Hickson, Thomas; Atit, Kinnari; Gagnier, Kristin; Resnick, Ilyse

2017-01-01

Spatial visualization is an essential prerequisite for understanding geological features at all scales, such as the atomic structures of minerals, the geometry of a complex fault system, or the architecture of sedimentary deposits. Undergraduate geoscience majors bring a range of spatial skill levels to upper-level courses. Fortunately, spatial…

Geologic evolution of the SE.23 Sheet - Belo Horizonte, MG, Brazil

International Nuclear Information System (INIS)

Pereira, A.D.C.; Fonseca, E.G. da; Braz, E.R.C.

1987-01-01

The aim of this paper is to present a synthesis of the geologic evolution in the Belo Horizonte Sheet comprising an area about 281.210 Km 2 . Rb-Sr and K-Ar isotope dating methods are used for age estimation of geologic deposits. The geologic evolution of the cratonic area is reflected by a stable central nucleus surrounded by marginal orogenic belts. In the central area were recognized greenstone belts structures involved by granite terrains and bordered by a granulitic region. The framework of the Sao Francisco Craton involves events of metamorphism, granitogenesis, sedimentary, volcanism and plutonism developed in the Early to Late Proterozoic. The stratigraphic column is complemented by Late Jurassic-Early Cretaceous continental deposits belonging to Parana-Basin. (M.V.M.)

Pre-Carboniferous sedimentary sequences of the northeastern flank of the Parana basin and southwestern of the Parnaiba basin and its uraniferous possibilites

International Nuclear Information System (INIS)

Andrade, S.M. de; Camarco, P.E.N.

1982-01-01

The analyses of the already existent geological data of the northeastern flank of the Parana Basin and the Southwestern flank of the Parnaiba Basin, added to new data from drilling and geological mapping allowed a better knowledge of the stratigraphy of the pre-carboniferous sedimentary sequences (silurian and devonian ages) as well as provided subsidies for the definition of its uranium possibilites. Besides the already known uranium deposits of the Ponta Grossa Formation, is should be considered as worth while of prospecting the Pimenteiras Formation. (Author) [pt

Shallow Sedimentary Structure of the Brahmaputra Valley Constraint from Receiver Functions Analysis

Science.gov (United States)

Saikia, Sowrav; Chopra, Sumer; Baruah, Santanu; Singh, Upendra K.

2017-01-01

In this study, receiver functions from ten Broadband seismograph stations on Cenozoic sediment formations of Brahmaputra valley and its neighboring region in northeastern part of India are determined. Receiver function traces from this region show delay in peak by 1-2.5 s and associated minor peaks with the direct P-phase peak. Based on such observation, we try to image sedimentary structure of the Brahmaputra valley plain, adjacent Shillong plateau and Himalayan foredeep region. An adapted hybrid global waveform inversion technique has been applied to extract sedimentary basin structure beneath each site. The sedimentary cover of the basin is about 0.5-6.5 km thick across the valley, 0.5-1.0 km on Shillong plateau and 2.0-5.0 km in nearby foredeep region. We have found that sedimentary thickness increases from SW to NE along the Brahmaputra valley and towards the Eastern Himalayan syntaxes. The estimated sediment thickness and S wave velocity structure agree well with the results of previous active source, gravity, and deep borehole studies carried out in this region. The thick crustal low velocity sediment cover in Brahmaputra valley is expected to amplify ground motions during earthquakes and therefore important for seismic hazard assessment of the region.

The Nysa-Morava Zone: an active tectonic domain with Late Cenozoic sedimentary grabens in the Western Carpathians' foreland (NE Bohemian Massif)

Czech Academy of Sciences Publication Activity Database

Špaček, P.; Bábek, O.; Štěpančíková, Petra; Švancara, J.; Pazdírková, J.; Sedláček, J.

2015-01-01

Roč. 104, č. 4 (2015), s. 963-990 ISSN 1437-3254 R&D Projects: GA ČR GAP210/12/0573; GA MŠk LM2010008 Institutional support: RVO:67985891 Keywords : Bohemian Massif * Upper Morava Basin * tectonic evolution * seismicity * sedimentary grabens Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.133, year: 2015

Sedimentary petrology of oil well rock cores; Petrologia sedimentaria de nucleos de rocas de pozos petroleros

Energy Technology Data Exchange (ETDEWEB)

Izquierdo M, Georgina; Paredes S, Adriana [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2001-07-01

At the request of PEMEX Exploration and Production (PEP), in the area of Geology of the Gerencia de Geotermia, the necessary methodology has been integrated to carry out the geologic characterization of cores obtained during the oil well drilling. The integrated studies have been of utility for PEMEX, because they provide detailed information on the processes, conditions of deposition and diagenesis that occur in sedimentary rocks. On the other hand, this geologic information contributes to the update of the geologic model of the field in study. [Spanish] A solicitud de PEMEX Exploracion y Produccion (PEP), en el area de Geologia de la Gerencia de Geotermia, se ha integrado la metodologia necesaria para llevar a cabo la caracterizacion geologica de nucleos obtenidos durante la perforacion de pozos petroleros. Los estudios integrados han sido de utilidad para PEMEX, pues proporcionan informacion detallada sobre los procesos, condiciones de depositacion y diagenesis que ocurren en rocas sedimentarias. Por otro lado, esta informacion geologica contribuye a la actualizacion del modelo geologico del campo en estudio.

The STRATAFORM Project: U.S. Geological Survey geotechnical studies

Science.gov (United States)

Minasian, Diane L.; Lee, Homa J.; Locat, Jaques; Orzech, Kevin M.; Martz, Gregory R.; Israel, Kenneth

2001-01-01

This report presents physical property logs of core samples from an offshore area near Eureka, CA. The cores were obtained as part of the STRATAFORM Program (Nittrouer and Kravitz, 1995, 1996), a study investigating how present sedimentation and sediment transport processes influence long-term stratigraphic sequences preserved in the geologic record. The core samples were collected during four separate research cruises to the northern California study area, and data shown in the logs of the cores were collected using a multi-sensor whole core logger. The physical properties collected are useful in identifying stratigraphic units, ground-truthing acoustic imagery and sub-bottom profiles, and in understanding mass movement processes. STRATA FORmation on Margins was initiated in 1994 by the Office of Naval Research, Marine Geology and Geophysics Department as a coordinated multi-investigator study of continental-margin sediment transport processes and stratigraphy (Nittrouer and Kravitz, 1996). The program is investigating the stratigraphic signature of the shelf and slope parts of the continental margins, and is designed to provide a better understanding of the sedimentary record and a better prediction of strata. Specifically, the goals of the STRATAFORM Program are to (Nittrouer and Kravitz, 1995): - determine the geological relevance of short-term physical processes that erode, transport, and deposit particles and those processes that subsequently rework the seabed over time scales - improve capabilities for identifying the processes that form the strata observed within the upper ~100 m of the seabed commonly representing 104-106 years of sedimentation. - synthesize this knowledge and bridge the gap between time scales of sedimentary processes and those of sequence stratigraphy. The STRATAFORM Program is divided into studies of the continental shelf and the continental slope; the geotechnical group within the U.S. Geological Survey provides support to both parts

U.S. Geological Survey Global Seismographic Network - Five-Year Plan 2006-2010

Science.gov (United States)

Leith, William S.; Gee, Lind S.; Hutt, Charles R.

2009-01-01

The Global Seismographic Network provides data for earthquake alerting, tsunami warning, nuclear treaty verification, and Earth science research. The system consists of nearly 150 permanent digital stations, distributed across the globe, connected by a modern telecommunications network. It serves as a multi-use scientific facility and societal resource for monitoring, research, and education, by providing nearly uniform, worldwide monitoring of the Earth. The network was developed and is operated through a partnership among the National Science Foundation (http://www.nsf.gov), the Incorporated Research Institutions for Seismology (http://www.iris.edu/hq/programs/gsn), and the U.S. Geological Survey (http://earthquake.usgs.gov/gsn).

Geologic map of the Bateman Spring Quadrangle, Lander County, Nevada

Science.gov (United States)

Ramelli, Alan R.; Wrucke, Chester T.; House, P. Kyle

2017-01-01

This 1:24,000-scale geologic map of the Bateman Spring 7.5-minute quadrangle in Lander County, Nevada contains descriptions of 24 geologic units and one cross section. Accompanying text includes full unit descriptions and references. This quadrangle includes lower Paleozoic siliciclastic sedimentary rocks of the Roberts Mountain allochthon, Miocene intrusive dikes, alluvial deposits of the northern Shoshone Range piedmont, and riverine deposits of the Reese and Humboldt rivers.Significant findings include: refined age estimates for the Ordovician-Cambrian Valmy Formation and Devonian Slaven Chert, based on new fossil information; and detailed mapping of late Quaternary fault traces along the Shoshone Range fault system.

Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands

Science.gov (United States)

Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.

2016-12-01

Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.

Analysis on metallogenetic geological and physicochemical conditions in uranium deposit No.138

International Nuclear Information System (INIS)

Tang Qitao

1996-01-01

The uranium deposit No.138 is of Mesozoic volcano-sedimentary transformation type. This paper discusses such geological conditions as source of uranium, stratigraphy and lithology, lithofacies and paleogeography, paleoclimate, structure and reworking-regeneration, and such physicochemical conditions as uranium adsorbent and reductant, effective porosity, chemical compositions, pH and Eh of rocks in the deposit

Geologic map of the Western Grove quadrangle, northwestern Arkansas

Science.gov (United States)

Hudson, Mark R.; Turner, Kenzie J.; Repetski, John E.

2006-01-01

This map summarizes the geology of the Western Grove 7.5-minute quadrangle in northern Arkansas that is located on the southern flank of the Ozark dome, a late Paleozoic regional uplift. The exposed bedrock of this map area comprises approximately 1,000 ft of Ordovician and Mississippian carbonate and clastic sedimentary rocks that have been mildly folded and broken by faults. A segment of the Buffalo River loops through the southern part of the quadrangle, and the river and adjacent lands form part of Buffalo National River, a park administered by the U.S. National Park Service. This geologic map provides information to better understand the natural resources of the Buffalo River watershed, particularly its karst hydrogeologic framework.

The geologic investigation of the bedrock and the tectonic and geophysical surveys at Kynnefjaell

International Nuclear Information System (INIS)

Ahlbom, K.; Ahlin, S.; Eriksson, L.; Samuelsson, L.

1980-05-01

The geologic survey took place at a selected area of Kynnefjaell. The result is given on geologic and tectonic maps. Two kinds of rock dominate, namely (a) sedimentary veined gneiss and (b) gneissic granite. The strike is in the N-S direction. A symmetric folds dip to the last. The fissure zones are oriented in the N-S and NE-SW directions. The latter zones are considered to be Precambrian shear zones with a dip to the NW. The dip of the fissure zones with the direction N-S is difficult to ascertain. The frequency of fissures is the same for granite and gneiss. The length of fissures is longer in the gneissic granite than in the sedimentary veined gneiss. The measurement of stress shows its main direction to be WNW-NW to ESE-SE. The fissure zones are at right or blunt-ended angles to the main stress direction. (G.B.)

Potensi sumber daya geologi di daerah Cekungan Bandung dan sekitarnya

Directory of Open Access Journals (Sweden)

Sutikno Bronto

2014-06-01

Full Text Available DOI: 10.17014/ijog.vol1no1.20062aGeologically, Bandung Basin and the surrounding area comprise volcanic rocks; therefore, originally the geological resources, such as energy, environmental geology and mineral were generated from past volcanic activities. Energy resources having been utilized or in the exploration stage are water energy (Saguling Electrical Hydro Power and geothermal energy (Darajat, Kamojang, Wayang-Windu and Patuha Geothermal Fields. Potency of hydrocarbon energy is considered due to the presence of Tertiary sedimentary rocks under Bandung volcanic rocks. Environmental resources include water, soil, land, and natural panorama that mostly are already used for living, tourism, industry etc. Mineral resources cover metals and non metals. Mineral explorations, particularly for gold, have been conducted in the southern Bandung area. Recently, Center for Geological Survey itself has found a new mineral resource in the northern Bandung, i.e. Cupunagara Village, Cisalak Sub-Regency, Subang Regency - West Jawa.    

The predictable nature of the Paleozoic sedimentary sequence beneath the Bruce nuclear site in Southern Ontario, Canada

International Nuclear Information System (INIS)

Parmenter, Andrew; Jensen, Mark; Crowe, Richard

2012-01-01

Document available in extended abstract form only. A key aspect of a Deep Geologic Repository (DGR) safety case is the ability to develop and communicate an understanding of the geologic stability and resilience to change at time frames relevant to demonstrating repository performance. As part of an on-going Environmental Assessment, Ontario Power Generation (OPG) recently completed site-specific investigations within an 850 m thick Paleozoic sedimentary sequence beneath the Bruce nuclear site for the proposed development of a DGR for Low and Intermediate Level Waste (L and ILW). As envisioned, the shaft-accessed DGR would be excavated at a nominal depth of 680 m within the low permeability Ordovician argillaceous limestone of the Cobourg Formation, which is overlain by more than 200 m of low permeability Ordovician shale. The geo-scientific investigations revealed a relatively undeformed and laterally continuous architecture within the sedimentary sequence at the repository scale (1.5 km 2 ) and beyond. This paper explores the predictable nature of the sedimentary sequence that has contributed to increasing confidence in an understanding of the spatial distribution of groundwater system properties, deep groundwater system evolution and natural barrier performance. Multi-disciplinary geo-scientific investigations of the Bruce nuclear site were completed in 3 phases between 2006 and 2010. The sub-surface investigations included a deep drilling, coring and in-situ testing program and, the completion of a 19.7 km (9 lines) 2-D seismic reflection survey. The drilling program involved 6 (150 mm dia.) deep boreholes (4-vertical; 2 inclined) that were extended through the sedimentary sequence from 4 drill sites, arranged around the 0.3 km 2 footprint of the proposed repository. The more than 3.8 km of rock core (77 mm dia.) retrieved have provided, in part, a strong basis to understand bedrock lithology and mineralogy, facies assemblages, structure, and oil and gas

U.S. Geological Survey climate and land use change science strategy: a framework for understanding and responding to global change

Science.gov (United States)

Burkett, Virginia R.; Kirtland, David A.; Taylor, Ione L.; Belnap, Jayne; Cronin, Thomas M.; Dettinger, Michael D.; Frazier, Eldrich L.; Haines, John W.; Loveland, Thomas R.; Milly, Paul C.D.; ,; ,; ,; Robert, S.; Maule, Alec G.; McMahon, Gerard; Striegl, Robert G.

2013-01-01

The U.S. Geological Survey (USGS), a nonregulatory Federal science agency with national scope and responsibilities, is uniquely positioned to serve the Nation’s needs in understanding and responding to global change, including changes in climate, water availability, sea level, land use and land cover, ecosystems, and global biogeochemical cycles. Global change is among the most challenging and formidable issues confronting our Nation and society. Scientists agree that global environmental changes during this century will have far-reaching societal implications (Intergovernmental Panel on Climate Change, 2007; U.S. Global Change Research Program, 2009). In the face of these challenges, the Nation can benefit greatly by using natural science information in decisionmaking.

Sedimentary basins reconnaissance using the magnetic Tilt-Depth method

Science.gov (United States)

Salem, A.; Williams, S.; Samson, E.; Fairhead, D.; Ravat, D.; Blakely, R.J.

2010-01-01

We compute the depth to the top of magnetic basement using the Tilt-Depth method from the best available magnetic anomaly grids covering the continental USA and Australia. For the USA, the Tilt-Depth estimates were compared with sediment thicknesses based on drilling data and show a correlation of 0.86 between the datasets. If random data were used then the correlation value goes to virtually zero. There is little to no lateral offset of the depth of basinal features although there is a tendency for the Tilt-Depth results to be slightly shallower than the drill depths. We also applied the Tilt-Depth method to a local-scale, relatively high-resolution aeromagnetic survey over the Olympic Peninsula of Washington State. The Tilt-Depth method successfully identified a variety of important tectonic elements known from geological mapping. Of particular interest, the Tilt-Depth method illuminated deep (3km) contacts within the non-magnetic sedimentary core of the Olympic Mountains, where magnetic anomalies are subdued and low in amplitude. For Australia, the Tilt-Depth estimates also give a good correlation with known areas of shallow basement and sedimentary basins. Our estimates of basement depth are not restricted to regional analysis but work equally well at the micro scale (basin scale) with depth estimates agreeing well with drill hole and seismic data. We focus on the eastern Officer Basin as an example of basin scale studies and find a good level of agreement between previously-derived basin models. However, our study potentially reveals depocentres not previously mapped due to the sparse distribution of well data. This example thus shows the potential additional advantage of the method in geological interpretation. The success of this study suggests that the Tilt-Depth method is useful in estimating the depth to crystalline basement when appropriate quality aeromagnetic anomaly data are used (i.e. line spacing on the order of or less than the expected depth to

Geologic and mineral and water resources investigations in western Colorado using ERTS-1 data

Science.gov (United States)

Knepper, D. H. (Principal Investigator)

1974-01-01

The author has identified the following significant results. Most of the geologic information in ERTS-1 imagery can be extracted from bulk processed black and white transparencies by a skilled interpreter using standard photogeologic techniques. In central and western Colorado, the detectability of lithologic contacts on ERTS-1 imagery is closely related to the time of year the imagery was acquired. Geologic structures are the most readily extractable type of geologic information contained in ERTS images. Major tectonic features and associated minor structures can be rapidly mapped, allowing the geologic setting of a large region to be quickly accessed. Trends of geologic structures in younger sedimentary appear to strongly parallel linear trends in older metamorphic and igneous basement terrain. Linears and color anomalies mapped from ERTS imagery are closely related to loci of known mineralization in the Colorado mineral belt.

Status and development of deep geological repository in Slovak republic from geological point of view

Directory of Open Access Journals (Sweden)

Jozef Franzen

2007-01-01

Full Text Available During the operation of Slovak NPPs, production of approximately 2,300 metric tons of spent fuel expressed as heavy metal (18,654 spent fuel assemblies is expected. In addition, about 5000 metric tons of radioactive waste unfit for near surface repository at Mochovce and destined for a deep geological disposal. The safe and long-term solution of back-end fuel cycle is so highly required.One of the most favorable solutions is Deep Geological Repository (DGR. The site for a DGR, along with repository design and the engineered barrier system must ensure long-term safety of the disposal system.A preliminary set of site-selection criteria for a DGR was proposed in Slovakia, based on worldwide experience and consistent with IAEA recommendations. Main groups of criteria are: 1 geological and tectonic stability of prospective sites; 2 appropriate characteristics of host rock (lithological homogeneity, suitable hydrogeological and geochemical conditions, favourable geotechnical setting, absence of mineral resources, etc.; 3 conflict of interests (natural resources, natural and cultural heritage, protected resources of thermal waters, etc..Based on the previous geological investigations, three distinct areas (five localities were determined as the most prospective sites for construction of a DGR so far. Three of them are built by granitoids rock (Tribeč Mts., Veporske vrchy Mts. and Stolicke vrchy Mts., other consist of sedimentary rock formations (Cerova vrchovina Upland and Rimavska kotlina Basin. Objective for the next investigation stage is to perform more detailed geological characterization of the prospective sites.

Geologic map of the Murray Quadrangle, Newton County, Arkansas

Science.gov (United States)

Hudson, Mark R.; Turner, Kenzie J.

2016-07-06

This map summarizes the geology of the Murray quadrangle in the Ozark Plateaus region of northern Arkansas. Geologically, the area is on the southern flank of the Ozark dome, an uplift that has the oldest rocks exposed at its center, in Missouri. Physiographically, the Murray quadrangle is within the Boston Mountains, a high plateau region underlain by Pennsylvanian sandstones and shales. Valleys of the Buffalo River and Little Buffalo River and their tributaries expose an approximately 1,600-ft-thick (488-meter-thick) sequence of Ordovician, Mississippian, and Pennsylvanian carbonate and clastic sedimentary rocks that have been mildly deformed by a series of faults and folds. The Buffalo National River, a park that encompasses the Buffalo River and adjacent land that is administered by the National Park Service is present at the northwestern edge of the quadrangle.Mapping for this study was carried out by field inspection of numerous sites and was compiled as a 1:24,000 geographic information system (GIS) database. Locations and elevation of sites were determined with the aid of a global positioning satellite receiver and a hand-held barometric altimeter that was frequently recalibrated at points of known elevation. Hill-shade relief and slope maps derived from a U.S. Geological Survey 10-meter digital elevation model as well as orthophotographs were used to help trace ledge-forming units between field traverses within the Upper Mississippian and Pennsylvanian part of the stratigraphic sequence. Strike and dip of beds were typically measured along stream drainages or at well-exposed ledges. Structure contours, constructed on the top of the Boone Formation and the base of a prominent sandstone unit within the Bloyd Formation, were drawn based on the elevations of field sites on these contacts well as other limiting information for their minimum elevations above hilltops or their maximum elevations below valley bottoms.

Evolution of fore-arc and back-arc sedimentary basins with focus on the Japan subduction system and its analogues

Science.gov (United States)

Sato, Hiroshi; Ishiyama, Tatsuya; Matenco, Liviu; Nader, Fadi Henri

2017-07-01

The International Lithosphere Program (ILP) seeks to elucidate the nature, dynamics, origin and evolution of the lithosphere through international, multidisciplinary geoscience research projects and coordinating committees (Cloetingh and Negendank, 2010). The focus of the Task Force VI Sedimentary Basins activities is to foster collaborations between academia, research institutes and industry in all domains relevant for the understanding of sedimentary basins, from regional to nano-scale, from the deep earth to near surface processes (e.g., Roure et al., 2010, 2013). In this activity, it is important to develop and validate novel concepts of sedimentary basin evolution and topography building by incorporating geological/geophysical datasets and methodologies applied to worldwide natural laboratories (Cloetingh et al., 2011; Cloetingh and Willett, 2013; Matenco and Andriessen, 2013). The Task Force aims to understand and predict the processes that control the formation and evolution of the coupled orogens and sedimentary basins system through integration of field studies, analytical techniques and numerical/analogue modelling. At the same time, the Task Force aims to promote research in the domain of sedimentary basins evolution and quantitative tectonics for the study of mountain building and the subsequent extensional collapse, and their quantitative implications for vertical motions on different temporal and spatial scales (Gibson et al., 2015; Matenco et al., 2016; Roure, 2008; Seranne et al., 2015). The implications of tectonics on basin fluids (fluid-flow and rock-fluid interactions) are important to understand and predict geo-resources (e.g., Nader, 2016). Important is to initiate innovative research lines in linking the evolution of sedimentary systems by integrating cross-disciplinary expertise with a focus on integrated sedimentary basins and orogenic evolution. The key is to strengthen the synergy between academic research and applied industry in large

Chemistry of decomposition of freshwater wetland sedimentary organic material during ramped pyrolysis

Science.gov (United States)

Williams, E. K.; Rosenheim, B. E.

2011-12-01

Ramped pyrolysis methodology, such as that used in the programmed-temperature pyrolysis/combustion system (PTP/CS), improves radiocarbon analysis of geologic materials devoid of authigenic carbonate compounds and with low concentrations of extractable authochthonous organic molecules. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves (Rosenheim et al., 2008) and constrained the carbon sequestration potential of suspended sediments in the lower Mississippi River (Roe et al., in review). Although ramped pyrolysis allows for separation of sedimentary organic material based upon relative reactivity, chemical information (i.e. chemical composition of pyrolysis products) is lost during the in-line combustion of pyrolysis products. A first order approximation of ramped pyrolysis/combustion system CO2 evolution, employing a simple Gaussian decomposition routine, has been useful (Rosenheim et al., 2008), but improvements may be possible. First, without prior compound-specific extractions, the molecular composition of sedimentary organic matter is unknown and/or unidentifiable. Second, even if determined as constituents of sedimentary organic material, many organic compounds have unknown or variable decomposition temperatures. Third, mixtures of organic compounds may result in significant chemistry within the pyrolysis reactor, prior to introduction of oxygen along the flow path. Gaussian decomposition of the reaction rate may be too simple to fully explain the combination of these factors. To relate both the radiocarbon age over different temperature intervals and the pyrolysis reaction thermograph (temperature (°C) vs. CO2 evolved (μmol)) obtained from PTP/CS to chemical composition of sedimentary organic material, we present a modeling framework developed based upon the ramped pyrolysis decomposition of simple mixtures of organic compounds (i.e. cellulose, lignin, plant fatty acids, etc.) often found in sedimentary

Geologic mapping of near-surface sediments in the northern Mississippi Embayment, McCracken County, KY

Energy Technology Data Exchange (ETDEWEB)

Sexton, Joshua L [JL Sexton and Son; Fryar, Alan E [Dept of Earth and Geoligical Sciences, Univ of KY,; Greb, s F [Univ of KY, KY Geological Survey

2006-04-01

POSTER: The Jackson Purchase region of western Kentucky consists of Coastal Plain sediments near the northern margin of the Mississippi Embayment. Within this region is the Paducah Gaseous Diffusion Plant (PGDP), a uranium enrichment facility operated by the US Department of Energy. At PGDP, a Superfund site, soil and groundwater studies have provided subsurface lithologic data from hundreds of monitoring wells and borings. Despite preliminary efforts by various contractors, these data have not been utilized to develop detailed stratigraphic correlations of sedimentary units across the study area. In addition, sedimentary exposures along streams in the vicinityof PGDP have not been systematically described beyond the relatively simple geologic quadrangle maps published by the US Geological Survey in 1966-67. This study integrates lithologic logs, other previous site investigation data, and outcrop mapping to provide a compilation of near-surface lithologic and stratigraphic data for the PGDP area. A database of borehole data compiled during this study has been provided to PGDP for future research and archival.

Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment

Digital Repository Service at National Institute of Oceanography (India)

Nath, B.N.; Khadge, N.H.; Nabar, S.; Raghukumar, C.; Ingole, B.S.; Valsangkar, A.B.; Sharma, R.; Srinivas, K.

1 Author version: Environ. Monit. Assess., vol.184; 2012; 2829-2844 Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment B. Nagender Nath * , N.H. Khadge, Sapana Nabar, C. Raghu Kumar, B.S. Ingole... community two years after an artificial rapid deposition event. Publication of Seto Marine Biological Laboratory, 39(1), 17-27. Gage, J.D. (1978). Animals in deep-sea sediments. Proceedings of Royal Society of Edinburgh, 768, 77-93. Gage, J.D., & Tyler...

OneGeology - Access to geoscience for all

Science.gov (United States)

Komac, Marko; Lee, Kathryn; Robida, Francois

2014-05-01

OneGeology is an initiative of Geological Survey Organisations (GSO) around the globe that dates back to Brighton, UK in 2007. Since then OneGeology has been a leader in developing geological online map data using a new international standard - a geological exchange language known as 'GeoSciML'. Increased use of this new language allows geological data to be shared and integrated across the planet with other organisations. One of very important goals of OneGeology was a transfer of valuable know-how to the developing world, hence shortening the digital learning curve. In autumn 2013 OneGeology was transformed into a Consortium with a clearly defined governance structure, making its structure more official, its operability more flexible and its membership more open where in addition to GSO also to other type of organisations that manage geoscientific data can join and contribute. The next stage of the OneGeology initiative will hence be focused into increasing the openness and richness of that data from individual countries to create a multi-thematic global geological data resource on the rocks beneath our feet. Authoritative information on hazards and minerals will help to prevent natural disasters, explore for resources (water, minerals and energy) and identify risks to human health on a planetary scale. With this new stage also renewed OneGeology objectives were defined and these are 1) to be the provider of geoscience data globally, 2) to ensure exchange of know-how and skills so all can participate, and 3) to use the global profile of 1G to increase awareness of the geosciences and their relevance among professional and general public. We live in a digital world that enables prompt access to vast amounts of open access data. Understanding our world, the geology beneath our feet and environmental challenges related to geology calls for accessibility of geoscientific data and OneGeology Portal (portal.onegeology.org) is the place to find them.

Geologic map of the Hasty Quadrangle, Boone and Newton Counties, Arkansas

Science.gov (United States)

Hudson, Mark R.; Murray, Kyle E.

2004-01-01

This digital geologic map compilation presents new polygon (for example, geologic map unit contacts), line (for example, fault, fold axis, and structure contour), and point (for example, structural attitude, contact elevations) vector data for the Hasty 7.5-minute quadrangle in northern Arkansas. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic, tectonic, and stratigraphic interest. The Hasty quadrangle is located in northern Newton and southern Boone Counties about 20 km south of the town of Harrison. The map area is underlain by sedimentary rocks of Ordovician, Mississippian, and Pennsylvanian age that were mildly deformed by a series of normal and strike-slip faults and folds. The area is representative of the stratigraphic and structural setting of the southern Ozark Dome. The Hasty quadrangle map provides new geologic information for better understanding groundwater flow paths in and adjacent to the Buffalo River watershed.

Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary and Crystalline Formations

Energy Technology Data Exchange (ETDEWEB)

Bruno, Mike S. [Terralog Technologies USA, Inc., Calgary (Canada); Detwiler, Russell L. [Terralog Technologies USA, Inc., Calgary (Canada); Lao, Kang [Terralog Technologies USA, Inc., Calgary (Canada); Serajian, Vahid [Terralog Technologies USA, Inc., Calgary (Canada); Elkhoury, Jean [Terralog Technologies USA, Inc., Calgary (Canada); Diessl, Julia [Terralog Technologies USA, Inc., Calgary (Canada); White, Nicky [Terralog Technologies USA, Inc., Calgary (Canada)

2012-12-13

There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. The primary objectives of this DOE research effort are to develop and document optimum design configurations and operating practices to produce geothermal power from hot permeable sedimentary and crystalline formations using advanced horizontal well recirculation systems. During Phase I of this research project Terralog Technologies USA and The University of California, Irvine (UCI), have completed preliminary investigations and documentation of advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. We have also identified significant geologic resources appropriate for application of such technology. The main challenge for such recirculation systems is to optimize both the design configuration and the operating practices for cost-effective geothermal energy recovery. These will be strongly influenced by sedimentary formation properties, including thickness and dip, temperature, thermal conductivity, heat capacity, permeability, and porosity; and by working fluid properties.

Study on remote sensing geologic information of uranium metallogeny in western Liaoning-northern Hebei region

International Nuclear Information System (INIS)

Yu Baoshan

1998-01-01

Based on the study on geologic metallogenic environment, temporal and spatial distribution and deposit features of uranium deposits in western Liaoning-northern Hebei region, summarizing mainly remote sensing information and synthesizing geologic, geophysical and geochemical as well as hydrological data, the author has implemented all-region joint-quadrangle analysis, composite mapping and applications, set up interpretation criteria for circular and arcuate structures of different lithological areas, and then expounded their geologic meaning. Volcanic apparatuses, small close sedimentary basins and magmatic rockbodies closely associated with uranium mineralizations, especially the altitude and types of ore-controlling structures and mineralized alteration zones have been interpreted. 'Heat halo spot' has also been interpreted on the satellite image and its geologic meaning and relation to uranium metallization have been discussed. Finally, remote sensing geologic prospecting model and comprehensive prediction model have been established

Study of Sedimentary Outcrop of Semanggol Formation with the Correlation of Geology, Geotechnical and Geophysics Technique

Science.gov (United States)

Nordiana, A. N.; Nordiana, M. M.; Jia, Teoh Ying; Hisham, Hazrul; Sulaiman, Nabila; Maslinda, Umi; Taqiuddin, Z. M.; Nur Amalina, M. K. A.; Afiq Saharudin, Muhamad

2017-04-01

The study location was at Bukit Kukus, Kuala Ketil, Kedah, Malaysia where the geological outcrop of this Semanggol Formation comprises of chert, mudstone, and volcanic tuff. The study was conducted using two geophysical methods, which are 2-D Resistivity and Ground Penetrating Radar (GPR). The objectives of the study are to correlate both of the geophysical methods through the value of conductivity and to identify the physical properties of rocks through the value of porosity and permeability. The data acquisition for both methods was conducted on the same line. For 2-D Resistivity method, the length of the line is 60 m with 1.5 m electrode spacing and the array used was Wenner-Schlumberger. For GPR method, the survey line was on top of the resistivity line, and the frequency of the antenna used is 250 MHz. A good correlation exists between both of the GPR signature and contour maps for resistivity from the surfer 10 software with the outcrop feature. Conductivity value from both GPR and Resistivity method was compared and the range value of conductivity obtained from GPR method almost equivalent with Resistivity method based on derivation and calculation for the sedimentary rocks, which are 0.037 to 0.574 miliSiemens per metre (mS/m) for chert and 0.186 to 10.142 miliSiemens per metre (mS/m) for mudstone. Two types of rock samples were taken, and several geotechnical tests were conducted, but only the value of permeability, K and porosity, ɸ of chert can be calculated, which are 1.95E-22 m2 (original condition) and 2.27E-22 m2 (dry condition) and 3 percent respectively as the sample of mudstone was damaged. The parameter of the 2-D resistivity method derived from Archie’s law was used to calculate the porosity, ɸf value using the Formation Factor equation. The range values of porosity, ɸf for chert mostly in the range of 5 to 25 percent, which is 6.26 to 13.36 percent but slightly out of range for mudstone, which is 14.12 to 36.02 percent.

The global marine phosphorus cycle: sensitivity to oceanic circulation

Directory of Open Access Journals (Sweden)

C. P. Slomp

2007-01-01

Full Text Available A new mass balance model for the coupled marine cycles of phosphorus (P and carbon (C is used to examine the relationships between oceanic circulation, primary productivity, and sedimentary burial of reactive P and particulate organic C (POC, on geological time scales. The model explicitly represents the exchanges of water and particulate matter between the continental shelves and the open ocean, and it accounts for the redox-dependent burial of POC and the various forms of reactive P (iron(III-bound P, particulate organic P (POP, authigenic calcium phosphate, and fish debris. Steady state and transient simulations indicate that a slowing down of global ocean circulation decreases primary production in the open ocean, but increases that in the coastal ocean. The latter is due to increased transfer of soluble P from deep ocean water to the shelves, where it fuels primary production and causes increased reactive P burial. While authigenic calcium phosphate accounts for most reactive P burial ocean-wide, enhanced preservation of fish debris may become an important reactive P sink in deep-sea sediments during periods of ocean anoxia. Slower ocean circulation globally increases POC burial, because of enhanced POC preservation under anoxia in deep-sea depositional environments and higher primary productivity along the continental margins. In accordance with geological evidence, the model predicts increased accumulation of reactive P on the continental shelves during and following periods of ocean anoxia.

A framework for predicting global silicate weathering and CO2 drawdown rates over geologic time-scales.

Science.gov (United States)

Hilley, George E; Porder, Stephen

2008-11-04

Global silicate weathering drives long-time-scale fluctuations in atmospheric CO(2). While tectonics, climate, and rock-type influence silicate weathering, it is unclear how these factors combine to drive global rates. Here, we explore whether local erosion rates, GCM-derived dust fluxes, temperature, and water balance can capture global variation in silicate weathering. Our spatially explicit approach predicts 1.9-4.6 x 10(13) mols of Si weathered globally per year, within a factor of 4-10 of estimates of global silicate fluxes derived from riverine measurements. Similarly, our watershed-based estimates are within a factor of 4-18 (mean of 5.3) of the silica fluxes measured in the world's ten largest rivers. Eighty percent of total global silicate weathering product traveling as dissolved load occurs within a narrow range (0.01-0.5 mm/year) of erosion rates. Assuming each mol of Mg or Ca reacts with 1 mol of CO(2), 1.5-3.3 x 10(8) tons/year of CO(2) is consumed by silicate weathering, consistent with previously published estimates. Approximately 50% of this drawdown occurs in the world's active mountain belts, emphasizing the importance of tectonic regulation of global climate over geologic timescales.

Role of ionizing radiation in the natural history of the Earth

International Nuclear Information System (INIS)

Byakov, V.M.; Stepanov, S.V.; Stepanova, O.P.

2001-01-01

A role of ionizing radiation in some global processes and events in geological history of the Earth is considered. In particular, we discuss: (1) the influence of ionizing radiation from radioactive nuclei disseminated in sedimentary rocks on the transformation of terrestrial organic matter into stone coals and oil; (2) the effect of cosmic rays from Supernova stars as a common cause of quasi-regular global geological processes and biocatastrophes. (author)

Geology Before Pluto: Pre-encounter Considerations

Science.gov (United States)

Moore, J. M.

2014-12-01

Pluto, its large satellite Charon, and its four small known satellites represent the first trans-Neptunian Kuiper Belt objects populating the outer-most solar system beyond the gas giant planets to be studied in detail from a spacecraft (New Horizons). A complete picture of the solar nebula and solar system formation cannot be confidently formulated until representatives of this group of bodies at the edge of solar space have been examined. The Pluto system is composed of unique, lunar- and intermediate-sized objects that can tell us much about how objects with volatile icy compositions evolve. Modeling of the interior suggests that geologic activity may have been significant to some degree, and observations of frost on the surface could imply the need for a geologic reservoir for the replenishment of these phases. However, these putative indicators of Pluto's geologic history are inconclusive and unspecific. Detailed examination of Pluto's geologic record is the only plausible means of bridging the gap between theory and observation. In this talk I will examine the potential importance of these tentative indications of geologic activity and how specific spacecraft observations have been designed and used to constrain the Pluto system's geologic history. The cameras of New Horizons will provide robust data sets that should be immanently amenable to geological analysis of the Pluto system's landscapes. In this talk, we begin with a brief discussion of the planned observations by the New Horizons cameras that will bear most directly on geological interpretability. Then I will broadly review major geological processes that could potentially operate on the surfaces of Pluto and its moons. I will first survey exogenic processes (i.e., those for which energy for surface modification is supplied externally to the planetary surface): impact cratering, sedimentary processes (including volatile migration), and the work of wind. I will conclude with an assessment of the

Geology Before Pluto: Pre-Encounter Considerations

Science.gov (United States)

Moore, Jeffrey M.

2014-01-01

Pluto, its large satellite Charon, and its four known satellites represent the first trans-Neptunian Kuiper Belt objects populating the outer-most solar system beyond the gas giant planets to be studied in detail from a spacecraft (New Horizons). A complete picture of the solar nebula, and solar system formation cannot be confidently formulated until representatives of this group of bodies at the edge of solar space have been examined. The Pluto system is composed of unique lunar- and intermediate-sized objects that can tell us much about how objects with volatile icy compositions evolve. Modeling of the interior suggests that geologic activity may have been to some degree, and observations of frost on the surface could imply the need for a geologic reservoir for the replenishment of these phases. However, the putative indicators of Pluto's geologic history are inconclusive and unspecific. Detailed examination of Pluto's geologic record is the only plausible means of bridging the gap between theory and observations. In this talk I will examine the potential importance of these tentative indications of geologic activity and how specific spacecraft observations have been designed and used to constrain the Pluto system's geologic history. The cameras of New Horizons will provide robust data sets that should be immanently amenable to geological analysis of the Pluto System's landscapes. In this talk, we begin with a brief discussion of the planned observations by New Horizons' cameras that will bear most directly on geological interpretability. Then I will broadly review major geological processes that could potentially operate of the surfaces of Pluto and its moons. I will first survey exogenic processes (i.e., those for which energy for surface modification is supplied externally to the planetary surface): impact cratering, sedimentary processes (including volatile migration) and the work of wind. I will conclude with an assessment of prospects for endogenic activity

GIS-project: geodynamic globe for global monitoring of geological processes

Science.gov (United States)

Ryakhovsky, V.; Rundquist, D.; Gatinsky, Yu.; Chesalova, E.

2003-04-01

reflect in diagram form a total combination and dynamics of data on the geological structure, geophysical fields, seismicity, geomagnetism, composition of rock complexes, and metalloge-ny of different areas on the Earth's surface. They give us possibility to scale, detail, and develop 3D spatial visualization. Information filling the covers could be replenished as in the existing so in newly formed databases with new data. The integrated analyses of the data allows us more precisely to define our ideas on regularities in development of lithosphere and mantle unhomogeneities using some original technologies. It also enables us to work out 3D digital models for geodynamic development of tectonic zones in convergent and divergent plate boundaries with the purpose of integrated monitoring of mineral resources and establishing correlation between seismicity, magmatic activity, and metallogeny in time-spatial co-ordinates. The created multifold geoinformation system gives a chance to execute an integral analyses of geoinformation flows in the interactive regime and, in particular, to establish some regularities in the time-spatial distribution and dynamics of main structural units in the lithosphere, as well as illuminate the connection between stages of their development and epochs of large and supperlarge mineral deposit formation. Now we try to use the system for prediction of large oil and gas concentration in the main sedimentary basins. The work was supported by RFBR, (grants 93-07-14680, 96-07-89499, 99-07-90030, 00-15-98535, 02-07-90140) and MTC.

Prediction of CO2 leakage during sequestration into marine sedimentary strata

International Nuclear Information System (INIS)

Li, Qi; Wu Zhishen; Li Xiaochun

2009-01-01

Deep ocean storage of CO 2 could help reduce the atmospheric level of greenhouse gas as part of a climate change mitigation strategy. In this paper, a multiphase flow model of CO 2 sequestration into deep ocean sediments was designed associated with the formation of CO 2 hydrates. A simplified assumption was proposed to predict the critical time of CO 2 leakage from marine sedimentary strata into seawater. Moreover, some principal parameters, which include the permeability, anisotropy, total injection amount, and length of the injection part of wellbores, were investigated by numerical simulations. The numerical estimates are used to assess the feasibility and effectiveness of CO 2 storage in deep ocean sediments. Accurately predicting the actual fate of liquid CO 2 sequestered into the marine sedimentary strata at depths greater than 500 m is complicated by uncertainties associated with not only the chemical-physical behavior of CO 2 under such conditions but also the geo-environment of disposal sites. Modeling results have shown some implications that the effectiveness of CO 2 ocean sequestration depends mainly on the injection conditions (such as injection rate, total injection amount, and the depth of injection), the site geology (such as permeability and anisotropy of disposal formations), and the chemical-physical behavior of CO 2 in marine environment

Incorporating the International Polar Year Into Introductory Geology Laboratories at Ohio State University

Science.gov (United States)

Judge, S. A.; Wilson, T. J.

2005-12-01

The International Polar Year (IPY) provides an excellent opportunity for highlighting polar research in education. The ultimate goal of our outreach and education program is to develop a series of modules that are focused on societally-relevant topics being investigated in Antarctic earth science, while teaching basic geologic concepts that are standard elements of school curricula. For example, we envision a university-level, undergraduate, introductory earth science class with the entire semester/quarter laboratory program focused on polar earth science research during the period of the International Polar Year. To attain this goal, a series of modules will be developed, including inquiry-based exercises founded on imagery (video, digital photos, digital core scans), GIS data layers, maps, and data sets available from OSU research groups. Modules that highlight polar research are also suitable for the K-12 audience. Scaleable/grade appropriate modules that use some of the same data sets as the undergraduate modules can be outlined for elementary through high school earth science classes. An initial module is being developed that focuses on paleoclimate data. The module provides a hands-on investigation of the climate history archived in both ice cores and sedimentary rock cores in order to understand time scales, drivers, and processes of global climate change. The paleoclimate module also demonstrates the types of polar research that are ongoing at OSU, allowing students to observe what research the faculty are undertaking in their respective fields. This will link faculty research with student education in the classroom, enhancing learning outcomes. Finally, this module will provide a direct link to U.S. Antarctic Program research related to the International Polar Year, when new ice and sedimentary rock cores will be obtained and analyzed. As a result of this laboratory exercise, the students will be able to: (1) Define an ice core and a sedimentary rock core

Hydrogeologic framework of fractured sedimentary rock, Newark Basin, New Jersey

Science.gov (United States)

Lacombe, Pierre J.; Burton, William C.

2010-01-01

The hydrogeologic framework of fractured sedimentary bedrock at the former Naval Air Warfare Center (NAWC), Trenton, New Jersey, a trichloroethylene (TCE)-contaminated site in the Newark Basin, is developed using an understanding of the geologic history of the strata, gamma-ray logs, and rock cores. NAWC is the newest field research site established as part of the U.S. Geological Survey Toxic Substances Hydrology Program, Department of Defense (DoD) Strategic Environmental Research and Development Program, and DoD Environmental Security Technology Certification Program to investigate contaminant remediation in fractured rock. Sedimentary bedrock at the NAWC research site comprises the Skunk Hollow, Byram, and Ewing Creek Members of the Lockatong Formation and Raven Rock Member of the Stockton Formation. Muds of the Lockatong Formation that were deposited in Van Houten cycles during the Triassic have lithified to form the bedrock that is typical of much of the Newark Basin. Four lithotypes formed from the sediments include black, carbon-rich laminated mudstone, dark-gray laminated mudstone, light-gray massive mudstone, and red massive mudstone. Diagenesis, tectonic compression, off-loading, and weathering have altered the rocks to give some strata greater hydraulic conductivity than other strata. Each stratum in the Lockatong Formation is 0.3 to 8 m thick, strikes N65 degrees E, and dips 25 degrees to 70 degrees NW. The black, carbon-rich laminated mudstone tends to fracture easily, has a relatively high hydraulic conductivity and is associated with high natural gamma-ray count rates. The dark-gray laminated mudstone is less fractured and has a lower hydraulic conductivity than the black carbon-rich laminated mudstone. The light-gray and the red massive mudstones are highly indurated and tend to have the least fractures and a low hydraulic conductivity. The differences in gamma-ray count rates for different mudstones allow gamma-ray logs to be used to correlate and

Stratigraphy and geologic history of Mercury

International Nuclear Information System (INIS)

Spudis, P.D.; Guest, J.E.

1988-01-01

The geologic evolution of Mercury based on the Mariner-10 mission data is discussed. As reconstructed through photogeological analysis of global geologic relations of rock-stratigraphic units, Mercury's geologic history is shown to involve intensive early impact bombardment and widespread resurfacing by volcanic lavas. Evidence is presented to indicate that this volcanic activity essentially ended as much as 3 Gyr ago, with most of the major geologic events being completed within the first 1 to 1.5 Gyr of Mercurian history

Stratigraphy and geologic history of Mercury

Science.gov (United States)

Spudis, Paul D.; Guest, John E.

1988-01-01

The geologic evolution of Mercury based on the Mariner-10 mission data is discussed. As reconstructed through photogeological analysis of global geologic relations of rock-stratigraphic units, Mercury's geologic history is shown to involve intensive early impact bombardment and widespread resurfacing by volcanic lavas. Evidence is presented to indicate that this volcanic activity essentially ended as much as 3 Gyr ago, with most of the major geologic events being completed within the first 1 to 1.5 Gyr of Mercurian history.

Caprock and overburden processes in geological CO2 storage: An experimental study on sealing efficiency and mineral alterations

NARCIS (Netherlands)

Wollenweber, J.; Alles, S.a.; Kronimus, A.; Busch, A.; Stanjek, H.; Krooss, B.M.

2009-01-01

A comprehensive set of experimental and analytical methods has been used to characterise the sealing and fluid -transport properties of fine-grained (pelitic) sedimentary rocks under the pressure and temperature conditions of geological CO2 storage. The flow experiments were carried out on

Geologic map of the Ponca quadrangle, Newton, Boone, and Carroll Counties, Arkansas

Science.gov (United States)

Hudson, Mark R.; Murray, Kyle E.

2003-01-01

This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, and structure contour), and point (i.e., structural attitude, contact elevations) vector data for the Ponca 7 1/2' quadrangle in northern Arkansas. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic, tectonic, and stratigraphic interest. The Ponca quadrangle is located in Newton, Boone, and Carroll Counties about 20 km southwest of the town of Harrison. The map area is underlain by sedimentary rocks of Ordovician, Mississippian, and Pennsylvanian age that were mildly deformed by a series of normal and strike-slip faults and folds. The area is representative of the stratigraphic and structural setting of the southern Ozark Dome. The Ponca quadrangle map provides new geologic information for better understanding groundwater flow paths and development of karst features in and adjacent to the Buffalo River watershed.

Evolution of the Toarcian (Early Jurassic) carbon-cycle and global climatic controls on local sedimentary processes (Cardigan Bay Basin, UK)

Science.gov (United States)

Xu, Weimu; Ruhl, Micha; Jenkyns, Hugh C.; Leng, Melanie J.; Huggett, Jennifer M.; Minisini, Daniel; Ullmann, Clemens V.; Riding, James B.; Weijers, Johan W. H.; Storm, Marisa S.; Percival, Lawrence M. E.; Tosca, Nicholas J.; Idiz, Erdem F.; Tegelaar, Erik W.; Hesselbo, Stephen P.

2018-02-01

The late Early Jurassic Toarcian Stage represents the warmest interval of the Jurassic Period, with an abrupt rise in global temperatures of up to ∼7 °C in mid-latitudes at the onset of the early Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma). The T-OAE, which has been extensively studied in marine and continental successions from both hemispheres, was marked by the widespread expansion of anoxic and euxinic waters, geographically extensive deposition of organic-rich black shales, and climatic and environmental perturbations. Climatic and environmental processes following the T-OAE are, however, poorly known, largely due to a lack of study of stratigraphically well-constrained and complete sedimentary archives. Here, we present integrated geochemical and physical proxy data (high-resolution carbon-isotope data (δ13 C), bulk and molecular organic geochemistry, inorganic petrology, mineral characterisation, and major- and trace-element concentrations) from the biostratigraphically complete and expanded entire Toarcian succession in the Llanbedr (Mochras Farm) Borehole, Cardigan Bay Basin, Wales, UK. With these data, we (1) construct the first high-resolution biostratigraphically calibrated chemostratigraphic reference record for nearly the complete Toarcian Stage, (2) establish palaeoceanographic and depositional conditions in the Cardigan Bay Basin, (3) show that the T-OAE in the hemipelagic Cardigan Bay Basin was marked by the occurrence of gravity-flow deposits that were likely linked to globally enhanced sediment fluxes to continental margins and deeper marine (shelf) basins, and (4) explore how early Toarcian (tenuicostatum and serpentinum zones) siderite formation in the Cardigan Bay Basin may have been linked to low global oceanic sulphate concentrations and elevated supply of iron (Fe) from the hinterland, in response to climatically induced changes in hydrological cycling, global weathering rates and large-scale sulphide and evaporite deposition.

3D coupled heat and mass transfer processes at the scale of sedimentary basisn

Science.gov (United States)

Cacace, M.; Scheck-Wenderoth, M.; Kaiser, B. O.

2014-12-01

We use coupled 3D simulations of fluid, heat, and transport based on a 3D structural model of a complex geological setting, the Northeast German Basin (NEGB). The geological structure of the NEGB is characterized by a relatively thick layer of Permian Zechstein salt, structured in differnet diapirs (up to 5000 m thick) and pillows locally reaching nearly the surface. Salt is thermally more conductive than other sediments, hydraulically impervious but highly solvable. Thus salt structures have first order influence on the temperature distribution, the deep flow regime and the salinity of groundawater bearing aquifers. In addition, the post-Permian sedimentary sequence is vertically subdivided into several aquifers and aquitards. The shallow Quaternary to late Tertiary freshwater aquifer is separated from the underlying Mesozoic saline aquifers by an embedded Tertiary clay enriched aquitard (Rupelian Aquitard). An important feature of this aquitard is that hydraulic connections between the upper and lower aquifers exist in areas where the Rupelian Aquitard is missing (hydrogeological windows). By means of 3D numerical simulations we explore the role of heat conduction, pressure, and density driven groundwater flow as well as fluid viscosity-related and salinity-dependent effects on the resulting flow and temperature fields. Our results suggest that the regional temperature distribution within the basin results from interactions between regional pressure forces and thermal diffusion locally enhanced by thermal conductivity contrasts between the different sedimentary rocks with the highly conductive salt. Buoyancy forces triggered by temperature-dependent fluid density variations affect only locally the internal thermal configuration. Locations, geometry, and wavelengths of convective thermal anomalies are mainly controlled by the permeability field and thickness values of the respective geological layers. Numerical results from 3D thermo-haline numerical simulations

Geology of the Arabian Peninsula; shield area of western Saudi Arabia

Science.gov (United States)

Brown, Glen F.; Schmidt, Dwight L.; Huffman, A. Curtis

1989-01-01

Western Arabia lies within the low-latitude desert of north Africa and the Middle East, the core being the Arabian segment of the African Shield. The core of complex basement rocks accounts for about 670,000 km2, or one-third of the Arabian Peninsula. Reconnaissance mapping of these crystalline rocks, together with bordering sedimentary rocks and volcanic flows, begun in 1950, resulted during the next 13 years in a series of geologic and geographic maps without extensive texts. The maps served as general guides for development of natural resources, including water supplies, ore deposits, and building materials. An intensive exploration program that began in 1963 and involved numerous geologists has vastly increased geologic information.

Two-dimensional simulation of clastic and carbonate sedimentation, consolidation, subsidence, fluid flow, heat flow and solute transport during the formation of sedimentary basins

Science.gov (United States)

Bitzer, Klaus

1999-05-01

Geological processes that create sedimentary basins or act during their formation can be simulated using the public domain computer code `BASIN'. For a given set of geological initial and boundary conditions the sedimentary basin evolution is calculated in a forward modeling approach. The basin is represented in a two-dimensional vertical cross section with individual layers. The stratigraphic, tectonic, hydrodynamic and thermal evolution is calculated beginning at an initial state, and subsequent changes of basin geometry are calculated from sedimentation rates, compaction and pore fluid mobilization, isostatic compensation, fault movement and subsidence. The sedimentologic, hydraulic and thermal parameters are stored at discrete time steps allowing the temporal evolution of the basin to be analyzed. A maximum flexibility in terms of geological conditions is achieved by using individual program modules representing geological processes which can be switched on and off depending on the data available for a specific simulation experiment. The code incorporates a module for clastic and carbonate sedimentation, taking into account the impact of clastic sediment supply on carbonate production. A maximum of four different sediment types, which may be mixed during sedimentation, can be defined. Compaction and fluid flow are coupled through the consolidation equation and the nonlinear form of the equation of state for porosity, allowing nonequilibrium compaction and overpressuring to be calculated. Instead of empirical porosity-effective stress equations, a physically consistent consolidation model is applied which incorporates a porosity dependent sediment compressibility. Transient solute transport and heat flow are calculated as well, applying calculated fluid flow rates from the hydraulic model. As a measure for hydrocarbon generation, the Time-Temperature Index (TTI) is calculated. Three postprocessing programs are available to provide graphic output in Post

Geochronology of the Jequie-Itabuna granulitic belt and of the Contendas-Mirante volcano-sedimentary belt

International Nuclear Information System (INIS)

Marinho, Moacyr M.; Barbosa, Johildo S.F.; Sabate, Pierre

1995-01-01

The Jequie-Itabuna Granulitic Belt is divided here into the Jequie-Mutuipe-Maracas Domain and the Atlantic Coast Domain. The paper analyzes the geochronological data from the Jequie-Mutuipe-Maracas Domain in two parts: plutonic rocks equilibrated in granulite facies, including the charno-enderbitic rocks from the Laje-Mutuipe region and the charnockitic rocks from the Maracas region; and ortho- and paraderived rocks metamorphosed in granulite facies, with the data obtained from rocks collected at the Jequie quarry and from homogeneous rocks collected at the western outskirts of the Jequirica town. The available geochronological data for the Atlantic Coast Domain is discussed, and due to the lack of petrologic control of the analyzed rocks, the geological significance of the ages between 2.0 and 2.3 is obtained in several line regressions. The paper identifies the following domains within the Contendas-Mirante volcano-sedimentary belt: the the basement dones, the volcano-sedimentary sequence and the intrusive rocks. The basement domes is the domain of the ancient gray gneisses (ca 3.4 Ga), to TTG (tonalite-trondhjemite-granodiorite) terrains and among the different massifs that crop out in the SE sector of the volcano-sedimentary belt, those of Sete Voltas and Boa Vista/Mata Verde have geochronological data available. The volcano-sedimentary sequence is divided into a lower, a middle and an upper unit and its available isotopic data are analyzed. The item referent to the intrusive rocks deals with the following plutons: The Lagoa Morro da Velha granitoid, the Pe da Serra granite, the Rio Jacare sill and the Transamazonian granites. 31 figs., 5 tabs

The investigation of sedimentary facies and stacking pattern in the Mulid River (Southeastern Qayen

Directory of Open Access Journals (Sweden)

Marzieh Fayazi Borujeni

2017-03-01

Full Text Available Introduction In the most gravel bed rivers, particle size exponentially decreases to the downstream. The study of particle size fining trend to the downstream and determination of the effective processes on it along the recent rivers is accomplished in the different parts of Iran. The river sedimentary facies are deposited in the channel and overbank areas and they are provided important information about sedimentary environment and deposition rate, the extent and development of the river channel and floodplain. These sedimentary facies that are deposited in the different depositional conditions have been achieved from variations of flow regime and/ or variation in the depositional environment in the large scale. The aim of this study is to investigate of the particle size variations and the effective controllers of fining trend to downstream, to determine of the important factors in creating sedimentary discontinuities and to study of the sedimentary facies, architectural elements, determination of depositional model and some paleohydraulic parameters of river. The Mulid River catchment with elongated shape is located in 120 km of southeast Qayen in the Southern Khorasan Province, in the 33̊ 24ʹ 44.3ʺ to 33̊ 35ʹ 11.4ʺ east latitude and 59̊ 56ʹ 42.5ʺ to 59̊ 58ʹ 44ʺ north longitude. According to the geological classification of Iran, this basin is a part of the East Iran flysch and mélange belt that is located in the east of the Lut Block.  Materials and Methods  In order to sedimentological studies, 30 sediment samples unsystematically were collected from upstream to downstream and from about 20 cm depth of the main channel bottom of river (with 30 km long. The granulometry analysis of the studied samples were achieved using the dry sieving method with 0.5 φ intervals and weight percent of gravel, sand and mud size particles were estimated. The sediment naming is done using Folk (1980 classification and the estimation of sorting

The Geological Susceptibility of Induced Earthquakes in the Duvernay Play

Science.gov (United States)

Pawley, Steven; Schultz, Ryan; Playter, Tiffany; Corlett, Hilary; Shipman, Todd; Lyster, Steven; Hauck, Tyler

2018-02-01

Presently, consensus on the incorporation of induced earthquakes into seismic hazard has yet to be established. For example, the nonstationary, spatiotemporal nature of induced earthquakes is not well understood. Specific to the Western Canada Sedimentary Basin, geological bias in seismogenic activation potential has been suggested to control the spatial distribution of induced earthquakes regionally. In this paper, we train a machine learning algorithm to systemically evaluate tectonic, geomechanical, and hydrological proxies suspected to control induced seismicity. Feature importance suggests that proximity to basement, in situ stress, proximity to fossil reef margins, lithium concentration, and rate of natural seismicity are among the strongest model predictors. Our derived seismogenic potential map faithfully reproduces the current distribution of induced seismicity and is suggestive of other regions which may be prone to induced earthquakes. The refinement of induced seismicity geological susceptibility may become an important technique to identify significant underlying geological features and address induced seismic hazard forecasting issues.

Fluvial response to abrupt global warming at the Palaeocene/Eocene boundary.

Science.gov (United States)

Foreman, Brady Z; Heller, Paul L; Clementz, Mark T

2012-11-01

Climate strongly affects the production of sediment from mountain catchments as well as its transport and deposition within adjacent sedimentary basins. However, identifying climatic influences on basin stratigraphy is complicated by nonlinearities, feedback loops, lag times, buffering and convergence among processes within the sediment routeing system. The Palaeocene/Eocene thermal maximum (PETM) arguably represents the most abrupt and dramatic instance of global warming in the Cenozoic era and has been proposed to be a geologic analogue for anthropogenic climate change. Here we evaluate the fluvial response in western Colorado to the PETM. Concomitant with the carbon isotope excursion marking the PETM we document a basin-wide shift to thick, multistoried, sheets of sandstone characterized by variable channel dimensions, dominance of upper flow regime sedimentary structures, and prevalent crevasse splay deposits. This progradation of coarse-grained lithofacies matches model predictions for rapid increases in sediment flux and discharge, instigated by regional vegetation overturn and enhanced monsoon precipitation. Yet the change in fluvial deposition persisted long after the approximately 200,000-year-long PETM with its increased carbon dioxide levels in the atmosphere, emphasizing the strong role the protracted transmission of catchment responses to distant depositional systems has in constructing large-scale basin stratigraphy. Our results, combined with evidence for increased dissolved loads and terrestrial clay export to world oceans, indicate that the transient hyper-greenhouse climate of the PETM may represent a major geomorphic 'system-clearing event', involving a global mobilization of dissolved and solid sediment loads on Earth's surface.

Outstanding diversity of heritage features in large geological bodies: The Gachsaran Formation in southwest Iran

Science.gov (United States)

Habibi, Tahereh; Ruban, Dmitry A.

2017-09-01

The ideas of geological heritage and geological diversity have become very popular in the modern science. These are usually applied to geological domains or countries, provinces, districts, etc. Additionally, it appears to be sensible to assess heritage value of geological bodies. The review of the available knowledge and the field investigation of the Gachsaran Formation (lower Miocene) in southwest Iran permit to assign its features and the relevant phenomena to as much as 10 geological heritage types, namely stratigraphical, sedimentary, palaeontological, palaeogeographical, geomorphological, hydrogeological, engineering, structural, economical, and geohistorical types. The outstanding diversity of the features of this formation determines its high heritage value and the national rank. The geological heritage of the Gachsaran Formation is important to scientists, educators, and tourists. The Papoon and Abolhaiat sections of this formation are potential geological heritage sites, although these do not represent all above-mentioned types. The large territory, where the Gachsaran Formation outcrop, has a significant geoconservation and geotourism potential, and further inventory of geosites on this territory is necessary. Similar studies of geological bodies in North Africa and the Middle East can facilitate better understanding of the geological heritage of this vast territory.

Gestures and metaphors as indicators of conceptual understanding of sedimentary systems

Science.gov (United States)

Riggs, E. M.; Herrera, J. S.

2012-12-01

Understanding the geometry and evolution of sedimentary systems and sequence stratigraphy is crucial to the development of geoscientists and engineers working in the petroleum industry. There is a wide variety of audiences within industry who require relatively advanced instruction in this area of geoscience, and there is an equally wide array of approaches to teaching this material in the classroom and field. This research was undertaken to develop a clearer picture of how conceptual understanding in this area of sedimentary geology grows as a result of instruction and how instructors can monitor the completeness and accuracy of student thinking and mental models. We sought ways to assess understanding that did not rely on model-specific jargon but rather was based in physical expression of basic processes and attributes of sedimentary systems. Advances in cognitive science and educational research indicate that a significant part of spatial cognition is facilitated by gesture, (e.g. giving directions, describing objects or landscape features). We aligned the analysis of gestures with conceptual metaphor theory to probe the use of mental image-schemas as a source of concept representation for students' learning of sedimentary processes. In order to explore image schemas that lie in student explanations, we focused our analysis on four core ideas about sedimentary systems that involve sea level change and sediment deposition, namely relative sea level, base level, and sea-level fluctuations and resulting basin geometry and sediment deposition changes. The study included 25 students from three U.S. Midwestern universities. Undergraduate and graduate-level participants were enrolled in senior-level undergraduate courses in sedimentology and stratigraphy. We used semi-structured interviews and videotaping for data collection. We coded the data to focus on deictic, iconic, and metaphoric gestures, and coded interview transcripts for linguistic metaphors using the

Interactions between sedimentary evolution and prehistoric human occupation in the south-central coast of Santa Catarina, Brazil

Directory of Open Access Journals (Sweden)

Paulo César Fonseca Giannini

2010-04-01

Full Text Available Since the beginning of the human occupation in the south-central coast of Santa Catarina State, in Brazil, the articulation between natural and anthropic processes modeled a strongly domesticated landscape, shaped by the massive construction of shell mounds of monumental dimensions and millenarian permanence. In the coastal plain between Passagem da Barra (Laguna District and Figueirinha Lake (Jaguaruna District, 76 sambaquis were mapped, 48 of which have been dated. Systematic site surveys and radiocarbon datings allowed identifying patterns of spatial distribution in sambaquis according to the sedimentary context at the time of construction, stratigraphy and age. Based on these criteria, the following groups were recognized: five geological-geomorphological contexts of location; three stratigraphic patterns; and four phases of sambaqui occupation in the area, based on site number and type of constructive pattern. The model for sedimentary evolution and time-space distribution of sambaquis shows that sites were built in already emerged areas and that inland sites, away from the lagoons, may have not be preserved or they are not exposed due to the continuous sedimentary filling that characterized this region after the maximum Holocene transgression. The crossing of data, here proposed, shows the importance of integral approaches between archaeology and geosciences for the study of landscape evolution.

Magnesium-to-calcium ratio in tap water, and its relationship to geological features and the incidence of calcium-containing urinary stones.

Science.gov (United States)

Kohri, K; Kodama, M; Ishikawa, Y; Katayama, Y; Takada, M; Katoh, Y; Kataoka, K; Iguchi, M; Kurita, T

1989-11-01

We examined the relationship among magnesium and calcium content in tap water, the geological features and urinary stone incidence in Japan. The magnesium-to-calcium ratio in tap water correlated negatively with the incidence of urolithiasis. There was no correlation between calcium and magnesium concentration in tap water and urinary stone incidence. Geological features in Japan were classified into 5 groups. The magnesium-to-calcium ratio in the basalt areas was higher than in the other areas, while ratio in the granite areas was low. In the sedimentary rock areas calcium and magnesium concentrations were high; the magnesium-to-calcium ratio in these areas was between those of the basalt and granite areas. The limestone areas had a much higher calcium concentration. The incidence of urinary stones in the sedimentary rock and basalt areas was lower than that of the granite areas, while that in the limestone areas was the highest. Thus, the incidence of urinary stone is related to the magnesium-to-calcium ratio in tap water and the geological area.

Stratigraphic sequence and sedimentary characteristics of Lower Silurian Longmaxi Formation in Sichuan Basin and its peripheral areas

Directory of Open Access Journals (Sweden)

Yuman Wang

2015-03-01

Full Text Available A high-precision sedimentary environment study of the Lower Silurian Longmaxi Formation is an important subject for shale gas exploration and development in Sichuan Basin and its surrounding areas. On the basis of outcrops and drilling data, its isochronous stratigraphic framework was built according to a particular graptolite zone and an important marker bed, and lithofacies, paleontology, calcareous content, well logging, geochemistry and other geologic information were combined to describe the sedimentary microfacies of Longmaxi Formation and its stratigraphic sequence, sedimentary evolution process and high quality shale distribution features as follows: ① with regional diachronism of the top and the bottom, the Longmaxi Formation is divided into two third-order sequences (SQ1 and SQ2, of which SQ1 is mainly an abyssal sedimentary assemblage deposited in the marine transgression period, and SQ2 is a bathyal to shallow sea sedimentary assemblage deposited in the marine regression period; ② there are eight microfacies such as deep calcareous shelf and deep argillaceous shelf in this formation and the organic-rich shale was mainly deposited in the deep water area of SQ1; and ③ from SQ1 to SQ2, the depocenter moved from the depression area in southern-eastern to northern Sichuan Basin, but the central Sichuan uplift remained an underwater one. It is concluded from this study that: ① shale gas production layers were mainly deposited in SQ1, the southern-eastern depression area was the depocenter in SQ1 and a shale gas enrichment area; and ② black shale in northern Sichuan was deposited in late SQ2, with limited distribution and relatively insufficient exploration potential, but the potential of shale gas exploration in western Hubei area is between southern-eastern and northern Sichuan Basin.

Study on the remote sensing geological information of uranium mineralization in Western Liaoning and Northern Hebei

International Nuclear Information System (INIS)

Yu Baoshan; Wang Dianbai; Jin Shihua; Qiao Rui

1996-01-01

Based on the whole areal geological map joint application rd exploitation, composite forming map, generalization analysis and field examination in detail of key region that mainly depend on remote sensing information and generalize the data of geology, geophysical and geochemical prospecting, and geohydrology, this paper reveals the structure framework, regional geological background, uranium metallogenic condition and space time distribution rule of orustal evolution and its result, and set up the interpretation marks of arc-shaped structure in different of rock area and discusses its geological genesis. The author also interprets volcanic apparatus, small type closed sedimentary basin, magmatic rock body which relate closely to uranium deposit, ore control structure and occurrence and type of mineralization alteration envelope. The thermal halo point of satellite image is emphatically interpreted and its geological meaning and its relation to uranium deposit is discussed. Remote sensing geological prospecting ore model and synthetic provision model is determined lastly

Discussions of the uranium geology working groups IGC, Sydney

International Nuclear Information System (INIS)

1978-01-01

The report is divided into six working group discussions on the following subjects: 1) Chemical and physical mechanisms in the formation of uranium mineralization, geochronology, isotope geology and mineralogy; 2) Sedimentary basins and sandstone-type uranium deposits; 3) Uranium in quartz-pebble conglomerates; 4) Vein and similar type deposits (pitchblende); 5) Other uranium deposits; 6) Relation of metallogenic, tectonic and zoning factors to the origin of uranium deposits. Each working group paper contains a short introductory part followed by a discussion by the working group members

Geologic Map of the Boxley Quadrangle, Newton and Madison Counties, Arkansas

Science.gov (United States)

Hudson, Mark R.; Turner, Kenzie J.

2007-01-01

This map summarizes the geology of the Boxley 7.5-minute quadrangle in the Ozark Plateaus region of northern Arkansas. Geologically, the area lies on the southern flank of the Ozark dome, an uplift that exposes oldest rocks at its center in Missouri. Physiographically, the Boxley quadrangle lies within the Boston Mountains, a high plateau region underlain by Pennsylvanian sandstones and shales. Valleys of the Buffalo River and its tributaries expose an approximately 1,600-ft-(490-m-)thick sequence of Ordovician, Mississippian, and Pennsylvanian carbonate and clastic sedimentary rocks that have been mildly deformed by a series of faults and folds. Part of Buffalo National River, a park encompassing the Buffalo River and adjacent land that is administered by the National Park Service, extends through the eastern part of the quadrangle. Mapping for this study was conducted by field inspection of numerous sites and was compiled as a 1:24,000-scale geographic information system (GIS) database. Locations and elevation sites were determined with the aid of a global positioning satellite receiver and a hand-held barometric altimeter. Hill-shade-relief and slope maps derived from a U.S. Geological Survey 10-m digital elevation model as well as orthophotos were used to help trace ledge-forming units between field traverses within the Upper Mississippian and Pennsylvanian part of the stratigraphic sequence. Strike and dip of beds were typically measured along stream drainages or at well-exposed ledges. Structure contours were constructed on the top of the Boone Formation and the base of a prominent sandstone unit within the Bloyd Formation based on elevations of control points as well as other limiting information on their maximum or minimum elevations.

Evaluating Geologic Sources of Arsenic in Well Water in Virginia (USA

Directory of Open Access Journals (Sweden)

Tiffany VanDerwerker

2018-04-01

Full Text Available We investigated if geologic factors are linked to elevated arsenic (As concentrations above 5 μg/L in well water in the state of Virginia, USA. Using geologic unit data mapped within GIS and two datasets of measured As concentrations in well water (one from public wells, the other from private wells, we evaluated occurrences of elevated As (above 5 μg/L based on geologic unit. We also constructed a logistic regression model to examine statistical relationships between elevated As and geologic units. Two geologic units, including Triassic-aged sedimentary rocks and Triassic-Jurassic intrusives of the Culpeper Basin in north-central Virginia, had higher occurrences of elevated As in well water than other geologic units in Virginia. Model results support these patterns, showing a higher probability for As occurrence above 5 μg/L in well water in these two units. Due to the lack of observations (<5% having elevated As concentrations in our data set, our model cannot be used to predict As concentrations in other parts of the state. However, our results are useful for identifying areas of Virginia, defined by underlying geology, that are more likely to have elevated As concentrations in well water. Due to the ease of obtaining publicly available data and the accessibility of GIS, this study approach can be applied to other areas with existing datasets of As concentrations in well water and accessible data on geology.

Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources

Science.gov (United States)

Williams, S.J.; Bliss, J.D.; Arsenault, M.A.; Jenkins, C.J.; Goff, J.A.

2007-01-01

Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

Rocks and geology in the San Francisco Bay region

Science.gov (United States)

Stoffer, Philip W.

2002-01-01

The landscape of the San Francisco Bay region is host to a greater variety of rocks than most other regions in the United States. This introductory guide provides illustrated descriptions of 46 common and important varieties of igneous, sedimentary, and metamorphic rock found in the region. Rock types are described in context of their identification qualities, how they form, and where they occur in the region. The guide also provides discussion about of regional geology, plate tectonics, the rock cycle, the significance of the selected rock types in relation to both earth history and the impact of mineral resources on the development in the region. Maps and text also provide information where rocks, fossils, and geologic features can be visited on public lands or in association with public displays in regional museums, park visitor centers, and other public facilities.

Current status and prospects of uranium geology developments of foreign in-situ leachable sandstone type uranium deposits

International Nuclear Information System (INIS)

Wang Zhengbang

2002-01-01

Firstly, with emphasis on in-situ leachable sandstone-type uranium deposits, the prospecting history of uranium deposits worldwide and its scientific research development are generally reviewed in four steps, and their basic historical experience is also summarized. Secondly, based on the detailed description of current development status of uranium geology of foreign in-situ leachable sandstone-type uranium deposits the important strategic position of sandstone-type uranium deposits in overall uranium resources all-over-the-world and its classification, spatial-temporal distribution and regulation, and metallogenic condition of sandstone-type uranium deposits are analysed thoroughly in five aspects: techtonics, paleo-climate, hydrogeology, sedimentary facies and lithology, as well as uranium sources: Afterwards, evaluation principles of three type of hyper-genic, epigenetic infiltrated sandstone-type uranium deposits are summarized. Based on sandstone-type uranium deposits located two important countries: the United States and Russia, the current development status of prospecting technology for in-situ leachable sandstone-type uranium deposits in foreign countries is outlined. Finally, according to the prospects of supply-demand development of global uranium resources, the author points out seriously that Chinese uranium geology is faced with a severe challenge, and proposes directly four strategic measures that should be taken

Recent Sedimentary Processes Along the Western Continental Margin of the South Korea Plateau, East Sea of Korea

Science.gov (United States)

Cukur, D.; Um, I. K.; Bahk, J. J.; Chun, J. H.; Lee, G. S.; Soo, K. G.; Horozal, S.; Kim, S. P.

2017-12-01

The continental margins of the marginal seas is largely shaped by a complex interplay of sediment transport processes directed both downslope and along-slope. Factors influence the sediment transport from shelf to the deep basin include: (i) seabed morphology, (ii) climate, (iii) sea level changes, (iv) slope stability, (v) oceanographic regime, and (vi) sediment sources. In order to understand the recent sedimentary processes along the western margin of the South Korea Plateau in the East Sea, we collected multiple geophysical datasets including the subbottom profiler and multibeam echosounder as well as geological sampling. Twelve echo types have been defined and interpreted as deposits formed by shallow marine, hemipelagic sedimentation, bottom currents, combined- (mass-movement/hemipelagic and hemipelagic/turbidites) and mass-movement-processes. Hemipelagic sedimentation, which is reflected as undisturbed layered sediments, appears to have been the primary sedimentary process throughout the study area. Two major slope-parallel channels appear to have acted as major conduits for turbidity currents from shallower shelf into the deep basins. Bottom current deposits, which is expressed as undulating seafloor morphology, are prevalent in the southern mid-slope at water depths between 250 to 450 m. Mass-transport deposits, consisting of chaotic seismic facies, occur in the upper and lower parts of the continental slope. Piston cores confirm the presence of MTDs that are characterized by mud clasts of variable size and shape. Multibeam bathymetry data show that these MTDs chiefly initiate on lower-slopes (400-600 m) where the gradient is up to 3°. In addition, subbottom profiles suggest the presence of numerous faults in close vicinity of headwall scarps; some are extending to the seafloor suggesting their recent activity. Earthquakes associated with tectonic activity are considered as the main triggering mechanism for these MTDs. Overall, the acoustic facies

Elemental Characteristics of Australian Sedimentary Opals and their Implications for Opal Formation and Gemstone Fingerprinting

Science.gov (United States)

Dutkiewicz, A.; Landgrebe, T. C.; Rey, P. F.

2011-12-01

Opal consists of amorphous SiO2.nH2O comprising a network of silica spheres, which in precious opal are of similar size and form an ordered network allowing light to diffract into an array of colors. Common opal, which is often associated with precious opal, lacks this play of color as it is composed of silica spheres of variable sizes. Australia supplies over 95% of the world's precious opal. The opal is almost exclusively located within Cretaceous sedimentary rocks of the Great Artesian Basin, which experienced a major phase of uplift in the Late Cretaceous with subsequent erosion removing a package of sedimentary rock up to 3 km in thickness. Intense weathering resulted in extensive silicification at relatively shallow levels within the Tertiary regolith. However, despite a billion dollar industry and a well-constrained geological history of the basin, the formation of sedimentary opal and its uniqueness to the Australian continent are still very poorly understood. In this study we have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on precious and common opal from key opal mining areas in order to constrain the possible sources of silica fluids involved in opal genesis and to assess whether any major or trace elements could be used to determine the provenance of opal with respect to a particular mining area. A total of 123 spots, each comprising 59 elements, including rare earth elements were analyzed. Globally, volcanic and sedimentary opals can be distinguished on the basis of Ba and Ca concentrations. Although the opals from the Great Artesian Basin are all sedimentary, some show Ba concentrations consistent with volcanic opals suggesting that silica fluids from which they formed were derived from a volcanic province. The most likely source is the Cretaceous volcanic-plutonic province of central Queensland, which supplied vast amounts of volcanogenic material into the Great Artesian Basin. The weathering of feldspars from the

Late Quaternary sedimentary dynamics in Western Amazonia: Implications for the origin of open vegetation/forest contrasts

Science.gov (United States)

Rossetti, D. F.; Bertani, T. C.; Zani, H.; Cremon, E. H.; Hayakawa, E. H.

2012-12-01

This work investigated the evolution of sedimentary environments during the latest Quaternary and their influence on the paradoxical occurrence of open vegetation patches in sharp contact with the Amazonian forest. The approach integrated pre-existing geological and floristic data from lowlands in the Brazilian Amazonia, with remote sensing imagery including multispectral optical images (TM, ETM+, and ASTER), Phased Array L-band Synthetic Aperture Radar (PALSAR), InSAR C-band SRTM-DEMs, and high resolution images obtained from Google Earth™. The detection of an abundance of paleomorphologies provided evidence of a scenario in which constant environmental shifts were linked to the evolution of fluvial and megafan depositional systems. In all studied areas, the open vegetation patches are not random, but associated with sedimentary deposits representative of environments either deactivated during the Holocene or presently in the process of deactivation. Sedimentary evolution would have determined the distribution of wetlands and terra firme in many areas of the Amazonian lowlands, and would have a major impact on the development of open vegetated patches within the modern rainforest. Subsiding areas were filled up with megafan deposits, and many fluvial tributaries were rearranged on the landscape. The close relationship between vegetation and the physical environment suggests that sedimentary history related to the evolution of depositional settings during the latest Quaternary played a major role in the distribution of flooded and non-flooded areas of the Amazonian lowlands, with a direct impact on the distribution of modern floristic patterns. As the depositional sites were abandoned and their sedimentary deposits were exposed to the surface, they became sites suitable for vegetation growth, first of herbaceous species and then of forest. Although climate fluctuations might have been involved, fault reactivation appears to have been the main cause of changes in

Uranium prospecting and geological favour ability in Uruguay

International Nuclear Information System (INIS)

Goso, H.

1981-01-01

Uranium prospecting carried out in Uruguay since 1976 is described. On the basis of literature available and of an analysis of the large structural units pertinent to Uruguay's geology, the prospecting performed in general in the northeast of the country, and in particular in the districts of Cerro Largo and Las Canas, is described. Some information is presented on uranium favour ability in Uruguay related to sedimentary formations: Devonian (Cerrezuelo Formation) and Gondwana (San Gregorio and Tres Islas Formations), and to the Crystalline formations of the centre and Southwest (1700-2000 m.y.) and of the east and southeast (500-700 m.y.)

Technique for large-scale structural mapping at uranium deposits i in non-metamorphosed sedimentary cover rocks

International Nuclear Information System (INIS)

Kochkin, B.T.

1985-01-01

The technique for large-scale construction (1:1000 - 1:10000), reflecting small amplitude fracture plicate structures, is given for uranium deposits in non-metamorphozed sedimentary cover rocks. Structure drill log sections, as well as a set of maps with the results of area analysis of hidden disturbances, structural analysis of iso-pachous lines and facies of platform mantle horizons serve as sour ce materials for structural mapplotting. The steps of structural map construction are considered: 1) structural carcass construction; 2) reconstruction of structure contour; 3) time determination of structure initiation; 4) plotting of an additional geologic load

Mineralizations of the Lavalleja Group (Uruguay), a Probable Neoproterozoic Volcano-sedimentary Sequence

International Nuclear Information System (INIS)

Sanchez Bettucci, L.; Oyhantcabal, P.; Loureiro, J.; Basei, M.; Ramos, V.; Preciozzi, F.; Basei, M.

2004-01-01

The Lavalleja Group is located in the southern extreme of the Dom Feliciano Belt, being tentatively correlated with the Porongos and Brusque Groups of Brazil. The basement of the Lavalleja Group is probably represented by granitic gneissic rocks of the Campanero Unit with ages, in the southern portion, ranging from 1.75 to 2.1 Ga (U-Pb in zircon). The Lavalleja Group is characterized by narrow bands of meta sedimentary and meta volcanic rocks and it is separated in three formations, namely (from base to top): Zanja del Tigre, Fuente del Puma and Minas. Outcrops assigned to the Minas Formation have been recently correlated with the Arroyo del Soldado Group. Only the Fuente del Puma formation hosts base metals, Au and Ag occurrences. The Fuente del Puma formation is divided into three informal units: sedimentary, volcanic and hornblenditic gabbros. The sedimentary unit is characterized by an important amount of carbonates. Syn collisional to pos tectonic granitic bodies (Carapé Complex) intrudes the Lavalleja Group and the Campanero Unit. Several mineralizations are located in the Fuente del Puma Formation, those associated to Arrospide, Ramallo-Reus, Chape, Valencia, La Oriental, Apolonia, Redondo Hill, La China and La Paloma mines are the most important. In addition, many occurrences of Cu-Zn-Pb were recognized in the region. The Cu-Zn-Pb mineralization includes massive sulfides with pyrite-chalcopyrite-sphalerite-galena-pyrrothyte, arsenopyrite-hematite into small bodies with lenticular shape. The host rock shows frequently hydrothermal alteration. The geochemistry and the geological features of the mineralizations suggest Besshi Massive Sulphide Zn-Cu-Pb and SEDEX Zn-Pb as most probably genetic models for the deposits related to the Neoproterozoic orogeny. Early mineralizations are syngenetic and were formed on the sea floor, although the main mineralizations are related to remobilization during syn- to late-metamorphic events and thrusting

Geological Structure and Radon Hazards in Lublin Region

Directory of Open Access Journals (Sweden)

Lucjan Gazda

2018-03-01

Full Text Available The purpose of the study was to show the relationship between the geological structure of the Lublin region (eastern Poland and radon concentrations in the ground air, and therefore, in the indoor environment of buildings located in that area. The study was based on the information pertaining to the geological structure of Lublin region available in the literature. The radon concentrations in buildings, caves, wells, as well as coal, phosphate and chalk mines were measured with both passive and active methods. Elemental analyses and uranium and lead isotope analyses of ground rocks were also performed. The conducted studies indicated that the sources of radon in Lublin region constitute Paleogene and Mesozoic sedimentary rocks rich in radionuclides. Application of radon remediation methods is recommended in the existing buildings located in the vicinity of these rocks, which are characterized by relatively high radon exhalations. On the other hand, the designed buildings should employ the measures protecting against harmful effects of radon presence.

Geologic map of the St. Joe quadrangle, Searcy and Marion Counties, Arkansas

Science.gov (United States)

Hudson, Mark R.; Turner, Kenzie J.

2009-01-01

This map summarizes the geology of the St. Joe 7.5-minute quadrangle in the Ozark Plateaus region of northern Arkansas. Geologically, the area lies on the southern flank of the Ozark dome, an uplift that exposes oldest rocks at its center in Missouri. Physiographically, the St. Joe quadrangle lies within the Springfield Plateau, a topographic surface generally held up by Mississippian cherty limestone. The quadrangle also contains isolated mountains (for example, Pilot Mountain) capped by Pennsylvanian rocks that are erosional outliers of the higher Boston Mountains plateau to the south. Tomahawk Creek, a tributary of the Buffalo River, flows through the eastern part of the map area, enhancing bedrock erosion. Exposed bedrock of this region comprises an approximately 1,300-ft-thick sequence of Ordovician, Mississippian, and Pennsylvanian carbonate and clastic sedimentary rocks that have been mildly deformed by a series of faults and folds. The geology of the St. Joe quadrangle was mapped by McKnight (1935) as part of a larger area at 1:125,000 scale. The current map confirms many features of this previous study, but it also identifies new structures and uses a revised stratigraphy. Mapping for this study was conducted by field inspection of numerous sites and was compiled as a 1:24,000-scale geographic information system (GIS) database. Locations and elevations of sites were determined with the aid of a global positioning satellite receiver and a hand-held barometric altimeter that was frequently recalibrated at points of known elevation. Hill-shade-relief and slope maps derived from a U.S. Geological Survey 10-m digital elevation model as well as U.S. Geological Survey orthophotographs from 2000 were used to help trace ledge-forming units between field traverses within the Upper Mississippian and Pennsylvanian part of the stratigraphic sequence. Strikes and dips of beds were typically measured along stream drainages or at well-exposed ledges. Beds dipping less

Geological exploration of uranium ores at Burgos' basin

International Nuclear Information System (INIS)

Cabrera Valdez, M.E.

1975-01-01

The outcrop sediments of the Burgos river basin cover the complete Cenozoic sequence from the Pallaeocene to recent date, and are arranged in the form of parallel strips with a regional dip towards the east, in which direction the sediments become steadily younger. Generally speaking they correspond to a regressive process the lithology of which is an alternation of shales, sandstones, tuffaceous material and conglomerates. The explorations and evaluations of sedimentary uranium deposits so far carried out in the north-east of Mexico show close relationships between the mineralization and the sedimentary processes of the enclosing rock. Analysis of the sedimentary-type uranium ore bodies in Mexico indicates characteristics very similar to those found in the deposits of the same type which were first studied and described in southern Texas and were used as a standard for the first exploratory studies. The uranium ore in the State of Texas is found in sands belonging mainly to the Jackson group of the Eocene and, to a lesser extent, the Catahoula formation of Miocene-Oligocene age. In the Burgos basin the existence of uranium deposits in the non-marine Frio formation of Oligocene age, with geological characteristics similar to the Texan deposits, has been demonstrated. This comparative analysis suggests very good prospects for uranium exploration in the region; it is recommended that priority be given to intensive study of the sediments of the non-marine member of the Frio formation, and the Jackson and Catahoula formations. (author)

Preliminary integration study of Precambrian with tectonic events in Brazilian sedimentary basins (Republication); Estudo preliminar de integracao do Pre-Cambriano com os eventos tectonicos das bacias sedimentares brasileiras (Republicacao)

Energy Technology Data Exchange (ETDEWEB)

Cordani, Umberto G.; Neves, Benjamim B. Brito; Fuck, Reinhard A.; Porto, Roberto; Thomaz Filho, Antonio; Cunha, Francisco M. Bezerra da

2008-11-15

The various successive episodes of vertical cratogenic evolution modelling the geo tectonic features of the basement were correlated with the internal structure, shape, origin and geologic evolution of the sedimentary basin. A systematic petrologic and geochronological investigation of all available drill core samples was carried out, and the pertinent geophysical data regarding basement structure were taken into consideration. Specific geo tectonic analyses, were carried out along the borders of the sedimentary basins, within the adjacent basement. The main boundaries between Precambrian tectonic provinces, the main tectonic sutures with polycyclic evolution, and the ancient intracratonic rifts were identified wherever possible. Their extensions under the sedimentary basins were inferred, corroboration being sought from structural information and data obtained from the drill core samples. It was found that many of the identified basement discontinuities had a direct influence on the depositional history of each of the sedimentary basins, demonstrating the distinct tectonic inheritance. The subject was treated on a reconnaissance scale, 1:1.000.000 or smaller,owing to its complexity. (author)

Querns and mills during Roman times at the northern frontier of the Roman Empire (Belgium, Northern France, Southern Netherlands, Western Germany: Unraveling geological and geographical provenances, a multidisciplinary research project

Directory of Open Access Journals (Sweden)

Sibrecht Reniere

2016-10-01

Full Text Available This paper presents the results of a multi-disciplinary provenance study of querns and millstones during the Roman period (1st-4th century CE in the northern part of the Roman Empire (provinces of Gallia Belgica and Germania Inferior. Comparative petrographical, mineralogical and geochemical analysis allowed an international team of archaeologists and geologists to identify the different raw materials used for the manufacturing of querns and millstones. As a result, (litho- stratigraphic assignments as well as geological-geographical provenances are suggested or corroborated for the broad spectrum of these natural geo-materials. We give evidence for the exploitation of at least seven different rock types. They include sedimentary rocks (fine- to coarse-grained quartzitic and arkosic sandstones, conglomerates, limestones and volcanic rocks (vesicular lavas derived from different geological strata in the following geological-geographical settings: the volcanic Eifel area (Pleistocene lava, the Ardennes Massif (Palaeozoic sedimentary rocks and the Paris and Northern Sea Basin (Cenozoic sedimentary rocks. Furthermore we show that a large diversity existed within different productions (different types of hand-mills and mechanical powered mills and distribution patterns. This paper provides new data which will lead to new insights into the socio-economics of the local “Gallo-Roman” communities and into their networks within the northern Roman Empire.

Geochemical element mobility during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin (Saskatchewan, Canada)

International Nuclear Information System (INIS)

Kister, Philippe

2003-01-01

In order to understand the mechanisms of migration and deposition of ore elements, it is essential to determine the timing, source, and destination of the geochemical element mass transfers and/or transportation on a scale encompassing the great sedimentary basins. The purpose of this study is to trace and to date the element migrations that occurred during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin, which hosts the world's largest and richest uranium deposits. As this geological environment was proved to be efficient to preserve high grade ore deposits for over more than one billion years, it provides an opportunity to study some natural analogues of deep geological nuclear waste storage. Five research topics were studied: 3D modelling of the distribution of normative minerals and trace elements on a basin-wide scale; U-Pb and Rb-Sr systematics; average chemical age estimation; thermodynamic modelling of the major mineralogical assemblages; U-Pb geochronology of uranium oxides. Some elements have remained immobile (Zr) since their initial sedimentary deposition, or were transferred from one phase to another (Al, Th). Other elements have been transported during fluid flow events that occurred: (1) on a basin wide scale during diagenesis (REE, Y, Sr, Fe), (2) at the unconformity and in the vicinity of the fault zones that represent preferential fluid flow pathways between the basement and the sandstone cover (U, Ni, As, B, Mg, K, Fe, Sr, REE), (3) during the late fault reactivation events associated with the basin uplift (U, Pb, Ni, S, Sr, REE). The successive tectonic events related to the geodynamical context that lead to the formation of these high-grade U concentrations (1460 Ma, 1335 Ma and 1275 Ma in the McArthur River deposit), did not however systematically occur in the whole basin (1275 Ma only at Shea Creek). The exceptionally high grade and tonnages of some deposits seem to be related to a larger number of U

Russian geological education in the world market (the case of Russian State Geological Prospecting University

Directory of Open Access Journals (Sweden)

Vasily Ivanovich Lisov

2016-12-01

Full Text Available Higher geological education in Russia and in MSGPI-RSGPU specific. It - engineering. The mineral deposits determine the development of the global industry and foreign trade. Growing global demand for the profession of geologists and mining engineers. Training of foreign students in Russia has its own geopolitical and economic importance. In Russia a strong resource-based economy. It attracts students from developing countries. MGRI-RSGPU is the leading universities training specialists for mining. The article presents data about the University and types of education. Shown scientific and educational problems in higher education. This article discusses the prospects for the promotion of Russian higher geological education at the world market of educational services. The increasing role of new scientific and technological achievements in mining, enhanced environmental as well as staff requirements is revealed. Given that the leading schools in the mining industry, in addition to Russia, are formed in Canada, Germany, USA, Australia, Great Britain, many developing countries rich in natural resources, have begun to form their own national centers for training in this area. Under such competitive conditions Russian geological education maintains its own niche. Recognition of this is the active participation of Russian universities in the creation and development of the World Forum of sustainable development of mineral universities (WFURS, described in the article. The main factors of competitiveness that led to leading positions of Russian State Geological Prospecting University in system of the Russian geological education are described. Particular attention is paid to the international activities of Russian higher educational institutions including Geological Prospecting University. The basic statistics (both in the context of the country, and in the field of foreign undergraduate and graduate students enrolled at this university is provided. The

The role of post-collisional strike-slip tectonics in the geological evolution of the late Neoproterozoic volcano-sedimentary Guaratubinha Basin, southern Brazil

Science.gov (United States)

Barão, Leonardo M.; Trzaskos, Barbara; Vesely, Fernando F.; de Castro, Luís Gustavo; Ferreira, Francisco J. F.; Vasconcellos, Eleonora M. G.; Barbosa, Tiago C.

2017-12-01

The Guaratubinha Basin is a late Neoproterozoic volcano-sedimentary basin included in the transitional-stage basins of the South American Platform. The aim of this study is to investigate its tectonic evolution through a detailed structural analysis based on remote sensing and field data. The structural and aerogeophysics data indicate that at least three major deformational events affected the basin. Event E1 caused the activation of the two main basin-bounding fault zones, the Guaratubinha Master Fault and the Guaricana Shear Zone. These structures, oriented N20-45E, are associated with well-defined right-lateral to oblique vertical faults, conjugate normal faults and vertical flow structures. Progressive transtensional deformation along the two main fault systems was the main mechanism for basin formation and the deposition of thick coarse-grained deposits close to basin-borders. The continuous opening of the basin provided intense intermediate and acid magmatism as well as deposition of volcaniclastic sediments. Event E2 characterizes generalized compression, recorded as minor thrust faults with tectonic transport toward the northwest and left-lateral activation of the NNE-SSW Palmital Shear Zone. Event E3 is related to the Mesozoic tectonism associated with the South Atlantic opening, which generated diabase dykes and predominantly right-lateral strike-slip faults oriented N10-50W. Its rhomboidal geometry with long axis parallel to major Precambrian shear zones, the main presence of high-angle, strike-slip or oblique faults, the asymmetric distribution of geological units and field evidence for concomitant Neoproterozoic magmatism and strike-slip movements are consistent with pull-apart basins reported in the literature.

Geology of the Integrated Disposal Facility Trench

International Nuclear Information System (INIS)

Reidel, Steve P.; Fecht, Karl R.

2005-01-01

This report describes the geology of the integrated Disposal Facility (IDF) Trench. The stratigraphy consists of some of the youngest sediments of the Missoula floods (younger than 770 ka). The lithology is dominated sands with minor silts and gravels that are largely unconsolidated. The stratigraphy can be subdivided into five geologic units that can be mapped throughout the trench. Four of the units were deposited by the Missoula floods and the youngest consists of windblown sand and silt. The sediment has little moisture and is consistent with that observed in the characterization boreholes. The sedimentary layers are flat lying and there are no faults or folds present. Two clastic dikes were encountered, one along the west wall and one that can be traced from the north to the southwall. The north-south clastic dike nearly bifurcates the trench but the west wall clastic dike can not be traced very far east into the trench. The classic dikes consist mainly of sand with clay-lined walls. The sediment in the dikes is compacted to partly cemented and are more resistant than the layered sediments

Estimation of Potential Carbon Dioxide Storage Capacities of Onshore Sedimentary Basins in Republic of Korea

Science.gov (United States)

Park, S.; Kim, J.; Lee, Y.

2010-12-01

The potential carbon dioxide storage capacities of the five main onshore sedimentary basins (Chungnam, Gyeongsang, Honam, Mungyeong, and Taebaeksan Basins) in Republic of Korea are estimated based on the methods suggested by the United States National Energy Technology Laboratory (NETL). The target geologic formations considered for geologic storage of carbon dioxide in the sedimentary basins are sandstone and coal beds. The density of carbon dioxide is set equal to 446.4 kg/m3. The adsorption capacity and density of coal (anthracite) are set equal to 2.71 × 10-2 kg/kg and 1.82 × 103 kg/m3, respectively. The average storage efficiency factors for sandstone and coal are set equal to 2.5% and 34.0%, respectively. The Chungnam Basin has the sandstone volume of 72 km3 and the coal volume of 1.24 km3. The average porosity of sandstone in the Chungnam Basin is 3.8%. As a result, the potential carbon dioxide storage capacities of sandstone and coal in the Chungnam Basin are estimated to be 31 Mton and 21 Mton, respectively. The Gyeongsang Basin has the sandstone volume of 1,960 km3. The average porosity of sandstone in the Gyeongsang Basin is 4.6%. As a result, the potential carbon dioxide storage capacity of sandstone in the Gyeongsang Basin is estimated to be 1,011 Mton. The Honam Basin has the sandstone volume of 8 km3 and the coal volume of 0.27 km3. The average porosity of sandstone in the Honam Basin is 1.9%. As a result, the potential carbon dioxide storage capacities of sandstone and coal in the Honam Basin are estimated to be 2 Mton and 5 Mton, respectively. The Mungyeong Basin has the sandstone volume of 60 km3 and the coal volume of 0.66 km3. The average porosity of sandstone in the Mungyeong Basin is 2.0%. As a result, the potential carbon dioxide storage capacities of sandstone and coal in the Mungyeong Basin are estimated to be 13 Mton and 11 Mton, respectively. The Taebaeksan Basin has the sandstone volume of 71 km3 and the coal volume of 0.73 km3. The

Stratigraphy of neoproterozoic sedimentary and volcano sedimentary successions of Uruguay

International Nuclear Information System (INIS)

Pecoits, E.; Aubet, N.; Oyhantcabal, P.; Sanchez Bettucci, L.

2004-01-01

Based on the new data the different characteristics of the Neoproterozoic (volcano) sedimentary succesions of Uruguay are described and discussed. Their stratigraphic tectonics and palaeoclimatic implications are analyzed.The results of the present investigations also allow to define the Maldonado Group which would beintegrated by the Playa Hermosa and Las Ventanas formations.

Sedimentary features and exploration targets of Middle Permian reservoirs in the SW Sichuan Basin

Directory of Open Access Journals (Sweden)

Guoming Xu

2015-11-01

Full Text Available The exploration direction and targets for the large-scale Middle Permian gas reservoirs in the Sichuan Basin are hot spots and challenges in current exploration researches. The exploration successes of large gas field of Cambrian Longwangmiao Formation in Gaoshiti-Moxi region, Central Sichuan Basin, indicated that prospective sedimentary facies belt was the basis for the formation of large gas fields. In this paper, based on seismic data, outcrop data and drilling data, the tectonic framework and sedimentary features of the Middle Permian in the SW Sichuan Basin were comprehensively studied. The following conclusions were reached from the perspective of sedimentary facies control: (1 during the Middle Permian, this region was in shallow water gentle slope belts with high energy, where thick reef flat facies were deposited; (2 the basement was uplifted during Middle Permian, resulting in the unconformity weathering crust at the top of Maokou Formation due to erosion; the SW Sichuan Basin was located in the karst slope belt, where epigenic karstification was intense; and (3 reef flat deposits superimposed by karst weathering crust was favorable for the formation of large-scale reef flat karst reservoirs. Based on the combination of the resources conditions and hydrocarbon accumulation conditions in this region, it was pointed out that the Middle Permian has great potential of large-scale reef flat karst gas reservoir due to its advantageous geological conditions; the Middle Permian traps with good hydrocarbon accumulation conditions were developed in the Longmen Mountain front closed structural belt in the SW Sichuan Basin and Western Sichuan Basin depression slope belt, which are favorable targets for large-scale reef flat karst reservoirs.

Metallogenic geologic conditions and prospecting direction of sandstone type uranium mineralizations in Yili basin of Xinjiang

International Nuclear Information System (INIS)

Chen Daisheng; Wang Ruiying; Li Shengxiang; Zhang Kefang

1994-09-01

Yili basin is a Mesozoic down-warped basin superimposed on the late Paleozoic volcanic taphrogenic basin. Uranium mineralizations are hosted in the Middle-Lower Jurassic coal-bearing series. The depositions environment in the basin is turbulent in the east and relatively stable in the west. It is characterized by coarse-grained sequence with thin thickness in the eastern part and fine-grained with thick thickness in the western part. On the analytical basis of sedimentary facies indices, it is the first time to present a sedimentary model of 'alluvial fan-braided stream-(narrow) lakeshore delta-lacustrine facies and marsh facies' for the coal-bearing series. The authors have summarized the basic geologic features of U-mineralizations in the interlayer oxidation zone, analyzed the difference and cause of U-mineralizations between the south and north, as well as the east and west. The genetic mechanism of U-mineralizations in the basin is discussed. Finally, seven items of geologic prerequisites for the formation of in-situ leachable sandstone type uranium deposits have been suggested and the potential of sandstone type U-mineralizations in the basin has been evaluated. Four promising target areas are selected

Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

Directory of Open Access Journals (Sweden)

Ziliang Liu

Full Text Available A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km. The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front

Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

Science.gov (United States)

Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

2015-01-01

A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km). The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front" character.

Geologic map of the Frisco quadrangle, Summit County, Colorado

Science.gov (United States)

Kellogg, Karl S.; Bartos, Paul J.; Williams, Cindy L.

2002-01-01

New 1:24,000-scale geologic mapping along the Interstate-70 urban corridor in western Colorado, in support of the USGS Central Region State/USGS Cooperative Geologic Mapping Project, is contributing to a more complete understanding of the stratigraphy, structure, tectonic evolution, and hazard potential of this rapidly developing region. The 1:24,000-scale Frisco quadrangle is near the headwaters of the Blue River and straddles features of the Blue River graben (Kellogg, K.S., 1999, Neogene basins of the northern Rio Grande rift?partitioning and asymmetry inherited from Laramide and older uplifts: Tectonophysics, v. 305, p. 141-152.), part of the northernmost reaches of the Rio Grande rift, a major late Oligocene to recent zone of extension that extends from Colorado to Mexico. The Williams Range thrust fault, the western structural margin of the Colorado Front Range, cuts the northeastern corner of the quadrangle. The oldest rocks in the quadrangle underlie the Tenmile Range and include biotite-sillimanite schist and gneiss, amphibolite, and migmatite that are intruded by granite inferred to be part of the 1,667-1,750 Ma Routt Plutonic Suite (Tweto, Ogden, 1987, Rock units of the Precambrian- basement in Colorado: U.S. Geological Survey Professional Paper 1321-A, 54 p.). The oldest sedimentary unit is the Pennsylvanian Maroon Formation, a sequence of red sandstone, conglomerate, and interbedded shale. The thickest sequence of sedimentary rocks is Cretaceous in age and includes at least 500 m of the Upper Cretaceous Pierre Shale. The sedimentary rocks are intruded by sills and dikes of dacite porphyry sills of Swan Mountain, dated at 44 Ma (Marvin, R.F., Mehnert, H.H., Naeser, C.W., and Zartman, R.E., 1989, U.S. Geological Survey radiometric ages, compilation ?C??Part five?Colorado, Montana, Utah, and Wyoming: Isochron/West, no. 53, p. 14-19. Simmons, E.C., and Hedge, C.E., 1978, Minor-element and Sr-isotope geochemistry of Tertiary stocks, Colorado mineral belt

Geologic map of the Nepenthes Planum Region, Mars

Science.gov (United States)

Skinner, James A.; Tanaka, Kenneth L.

2018-03-26

This map product contains a map sheet at 1:1,506,000 scale that shows the geology of the Nepenthes Planum region of Mars, which is located between the cratered highlands that dominate the southern hemisphere and the less-cratered sedimentary plains that dominate the northern hemisphere.  The map region contains cone- and mound-shaped landforms as well as lobate materials that are morphologically similar to terrestrial igneous or mud vents and flows. This map is part of an informal series of small-scale (large-area) maps aimed at refining current understanding of the geologic units and structures that make up the highland-to-lowland transition zone. The map base consists of a controlled Thermal Emission Imaging System (THEMIS) daytime infrared image mosaic (100 meters per pixel resolution) supplemented by a Mars Orbiter Laser Altimeter (MOLA) digital elevation model (463 meters per pixel resolution). The map includes a Description of Map Units and a Correlation of Map Units that describes and correlates units identified across the entire map region. The geologic map was assembled using ArcGIS software by Environmental Systems Research Institute (http://www.esri.com). The ArcGIS project, geodatabase, base map, and all map components are included online as supplemental data.

NATURAL GAS RESOURCES IN DEEP SEDIMENTARY BASINS

Energy Technology Data Exchange (ETDEWEB)

Thaddeus S. Dyman; Troy Cook; Robert A. Crovelli; Allison A. Henry; Timothy C. Hester; Ronald C. Johnson; Michael D. Lewan; Vito F. Nuccio; James W. Schmoker; Dennis B. Riggin; Christopher J. Schenk

2002-02-05

From a geological perspective, deep natural gas resources are generally defined as resources occurring in reservoirs at or below 15,000 feet, whereas ultra-deep gas occurs below 25,000 feet. From an operational point of view, ''deep'' is often thought of in a relative sense based on the geologic and engineering knowledge of gas (and oil) resources in a particular area. Deep gas can be found in either conventionally-trapped or unconventional basin-center accumulations that are essentially large single fields having spatial dimensions often exceeding those of conventional fields. Exploration for deep conventional and unconventional basin-center natural gas resources deserves special attention because these resources are widespread and occur in diverse geologic environments. In 1995, the U.S. Geological Survey estimated that 939 TCF of technically recoverable natural gas remained to be discovered or was part of reserve appreciation from known fields in the onshore areas and State waters of the United. Of this USGS resource, nearly 114 trillion cubic feet (Tcf) of technically-recoverable gas remains to be discovered from deep sedimentary basins. Worldwide estimates of deep gas are also high. The U.S. Geological Survey World Petroleum Assessment 2000 Project recently estimated a world mean undiscovered conventional gas resource outside the U.S. of 844 Tcf below 4.5 km (about 15,000 feet). Less is known about the origins of deep gas than about the origins of gas at shallower depths because fewer wells have been drilled into the deeper portions of many basins. Some of the many factors contributing to the origin of deep gas include the thermal stability of methane, the role of water and non-hydrocarbon gases in natural gas generation, porosity loss with increasing thermal maturity, the kinetics of deep gas generation, thermal cracking of oil to gas, and source rock potential based on thermal maturity and kerogen type. Recent experimental simulations

Geology and mineral occurences of braquiantidinal do Lontra - GO

International Nuclear Information System (INIS)

Macambira, J.B.

1983-01-01

This work involved the geological mapping (in the scale 1:60.000) of an area of 800 square kilometers in the nortwestern part of the state of Goias, near and east of the Araguaia river. Based on the stratigraphy, metamorphism, geochronology, magmatism and mineral deposits hypotheses on the geological evolution of the region are discussed. The area studied belongs to the Precambrian Araguaia Fold Belt. The oldest rocks identified are trondhjemitic gneisses and on these rocks was deposited a sedimentary sequence with minor volcanics of a geosynclinal type. The stratigraphic column of Abreu (1978) was adopted with minor modifications. The basement, of transamazonic age (2000 Ma), consists mostly of gneiss, migmatite, granite gneiss and amphibolite. The metasediments belongs to the lower unit (Estrondo Group) of the Supergroup Baixo Araguaia. The Estrondo Group, of brasilian age (600 Ma), consists in the area of the lowermost Morro do Campo Formation, mainly quartzite and amphibolite, which give the high relief of the brachyanticlines of Lontra and Ramal do Lontra.(author)

MORPHOLOGICAL AND GEOLOGICAL INDICATORS OF THE POSSIBLE BAUXITE DEPOSITS IN THE KARST REGION OF WESTERN HERZEGOVINA

Directory of Open Access Journals (Sweden)

Ivan Blašković

1995-12-01

Full Text Available Investigation results of morphological and geological potential bauxite deposit indicators in the Mesihovina-Rakitno bauxitebearing sedimentary basin in Western Herzegovina are presented. Region with carbonate and clastic hangingwalls as well as those without overlying sediments have been studied. It was established that the expression and number of the indicators depend size as well as on character and thickness of hangingwall sediments. The morphological indicators are expressed as a particular relief forms situated right above the deposits or nearby and are a consequence of geological relations and exodynamic processes. Ihe numerous geological indicators resulted from complex geological events. The most important are: preore structural relations, the formation of paleorelief, peculiar way of hangingwall rocks sedimentation, lithification processes and the formation of the recent structural pattern. It has been observed that particular indicators should be recognized within a relatively thick succession of the overlying sediments which is of the great importance in the exploration of bauxite deposits.

3D Geological Model for "LUSI" - a Deep Geothermal System

Science.gov (United States)

Sohrabi, Reza; Jansen, Gunnar; Mazzini, Adriano; Galvan, Boris; Miller, Stephen A.

2016-04-01

Geothermal applications require the correct simulation of flow and heat transport processes in porous media, and many of these media, like deep volcanic hydrothermal systems, host a certain degree of fracturing. This work aims to understand the heat and fluid transport within a new-born sedimentary hosted geothermal system, termed Lusi, that began erupting in 2006 in East Java, Indonesia. Our goal is to develop conceptual and numerical models capable of simulating multiphase flow within large-scale fractured reservoirs such as the Lusi region, with fractures of arbitrary size, orientation and shape. Additionally, these models can also address a number of other applications, including Enhanced Geothermal Systems (EGS), CO2 sequestration (Carbon Capture and Storage CCS), and nuclear waste isolation. Fractured systems are ubiquitous, with a wide-range of lengths and scales, making difficult the development of a general model that can easily handle this complexity. We are developing a flexible continuum approach with an efficient, accurate numerical simulator based on an appropriate 3D geological model representing the structure of the deep geothermal reservoir. Using previous studies, borehole information and seismic data obtained in the framework of the Lusi Lab project (ERC grant n°308126), we present here the first 3D geological model of Lusi. This model is calculated using implicit 3D potential field or multi-potential fields, depending on the geological context and complexity. This method is based on geological pile containing the geological history of the area and relationship between geological bodies allowing automatic computation of intersections and volume reconstruction. Based on the 3D geological model, we developed a new mesh algorithm to create hexahedral octree meshes to transfer the structural geological information for 3D numerical simulations to quantify Thermal-Hydraulic-Mechanical-Chemical (THMC) physical processes.

Assessing correlations between geological hazards and health outcomes: Addressing complexity in medical geology.

Science.gov (United States)

Wardrop, Nicola Ann; Le Blond, Jennifer Susan

2015-11-01

The field of medical geology addresses the relationships between exposure to specific geological characteristics and the development of a range of health problems: for example, long-term exposure to arsenic in drinking water can result in the development of skin conditions and cancers. While these relationships are well characterised for some examples, in others there is a lack of understanding of the specific geological component(s) triggering disease onset, necessitating further research. This paper aims to highlight several important complexities in geological exposures and the development of related diseases that can create difficulties in the linkage of exposure and health outcome data. Several suggested approaches to deal with these complexities are also suggested. Long-term exposure and lengthy latent periods are common characteristics of many diseases related to geological hazards. In combination with long- or short-distance migrations over an individual's life, daily or weekly movement patterns and small-scale spatial heterogeneity in geological characteristics, it becomes problematic to appropriately assign exposure measurements to individuals. The inclusion of supplementary methods, such as questionnaires, movement diaries or Global Positioning System (GPS) trackers can support medical geology studies by providing evidence for the most appropriate exposure measurement locations. The complex and lengthy exposure-response pathways involved, small-distance spatial heterogeneity in environmental components and a range of other issues mean that interdisciplinary approaches to medical geology studies are necessary to provide robust evidence. Copyright © 2015. Published by Elsevier Ltd.

Integrating Natural Gas Hydrates in the Global Carbon Cycle

Energy Technology Data Exchange (ETDEWEB)

David Archer; Bruce Buffett

2011-12-31

We produced a two-dimensional geological time- and basin-scale model of the sedimentary margin in passive and active settings, for the simulation of the deep sedimentary methane cycle including hydrate formation. Simulation of geochemical data required development of parameterizations for bubble transport in the sediment column, and for the impact of the heterogeneity in the sediment pore fluid flow field, which represent new directions in modeling methane hydrates. The model is somewhat less sensitive to changes in ocean temperature than our previous 1-D model, due to the different methane transport mechanisms in the two codes (pore fluid flow vs. bubble migration). The model is very sensitive to reasonable changes in organic carbon deposition through geologic time, and to details of how the bubbles migrate, in particular how efficiently they are trapped as they rise through undersaturated or oxidizing chemical conditions and the hydrate stability zone. The active margin configuration reproduces the elevated hydrate saturations observed in accretionary wedges such as the Cascadia Margin, but predicts a decrease in the methane inventory per meter of coastline relative to a comparable passive margin case, and a decrease in the hydrate inventory with an increase in the plate subduction rate.

GEOLOGICAL-GEOPHYSICAL EXPLORATION OF THE BAUXITE DEPOSITS APPLICATION OF THE SHALLOW SEIZMIC REFLECTION METHOD

Directory of Open Access Journals (Sweden)

Ivan Dragičević

1991-12-01

Full Text Available The exploration of bauxite deposits in the region of the carbonaceous Dinarides has been performed by using different geological and geophysical methods. Deposits laying shallower or deeper below the roof sediments have so far most often been discovered by expensive drilling methods in a corresponding grid. Complex geological explorations have led to a series of valuable data thus enabling the application of other much more economical methods as well. In the region of the bauxite sedimentary basin Mesihovina-Rakitno, western Herzegovina, at the site of Studena vrila - after extensive geological explorations - a conclusion was drawn that the shallow seismic reflection geophysical method as well might be successfully applied in locating new bauxite deposits. In the paper, the geological framework of the bauxite deposits occurrences, stipulating the selection of this methode, will be presented. Measurements were performed on a known deposit (L-84, Povaljenica, completely defined by exploration drilling. The obtained results justify the selection of the shallow seismic reflection method as one of the methods for exploring bauxite deposits beneath the roof beds.

Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks.

Science.gov (United States)

Bourg, Ian C; Ajo-Franklin, Jonathan B

2017-09-19

The ability to predict the permeability of fine-grained soils, sediments, and sedimentary rocks is a fundamental challenge in the geosciences with potentially transformative implications in subsurface hydrology. In particular, fine-grained sedimentary rocks (shale, mudstone) constitute about two-thirds of the sedimentary rock mass and play important roles in three energy technologies: petroleum geology, geologic carbon sequestration, and radioactive waste management. The problem is a challenging one that requires understanding the properties of complex natural porous media on several length scales. One inherent length scale, referred to hereafter as the mesoscale, is associated with the assemblages of large grains of quartz, feldspar, and carbonates over distances of tens of micrometers. Its importance is highlighted by the existence of a threshold in the core scale mechanical properties and regional scale energy uses of shale formations at a clay content X clay ≈ 1/3, as predicted by an ideal packing model where a fine-grained clay matrix fills the gaps between the larger grains. A second important length scale, referred to hereafter as the nanoscale, is associated with the aggregation and swelling of clay particles (in particular, smectite clay minerals) over distances of tens of nanometers. Mesoscale phenomena that influence permeability are primarily mechanical and include, for example, the ability of contacts between large grains to prevent the compaction of the clay matrix. Nanoscale phenomena that influence permeability tend to be chemomechanical in nature, because they involve strong impacts of aqueous chemistry on clay swelling. The second length scale remains much less well characterized than the first, because of the inherent challenges associated with the study of strongly coupled nanoscale phenomena. Advanced models of the nanoscale properties of fine-grained media rely predominantly on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, a mean field

Geologic hazards in the region of the Hurricane fault

Science.gov (United States)

Lund, W.R.

1997-01-01

Complex geology and variable topography along the 250-kilometer-long Hurricane fault in northwestern Arizona and southwestern Utah combine to create natural conditions that can present a potential danger to life and property. Geologic hazards are of particular concern in southwestern Utah, where the St. George Basin and Interstate-15 corridor north to Cedar City are one of Utah's fastest growing areas. Lying directly west of the Hurricane fault and within the Basin and Range - Colorado Plateau transition zone, this region exhibits geologic characteristics of both physiographic provinces. Long, potentially active, normal-slip faults displace a generally continuous stratigraphic section of mostly east-dipping late Paleozoic to Cretaceous sedimentary rocks unconformably overlain by Tertiary to Holocene sedimentary and igneous rocks and unconsolidated basin-fill deposits. Geologic hazards (exclusive of earthquake hazards) of principal concern in the region include problem soil and rock, landslides, shallow ground water, and flooding. Geologic materials susceptible to volumetric change, collapse, and subsidence in southwestern Utah include; expansive soil and rock, collapse-prone soil, gypsum and gypsiferous soil, soluble carbonate rocks, and soil and rock subject to piping and other ground collapse. Expansive soil and rock are widespread throughout the region. The Petrified Forest Member of the Chinle Formation is especially prone to large volume changes with variations in moisture content. Collapse-prone soils are common in areas of Cedar City underlain by alluvial-fan material derived from the Moenkopi and Chinle Formations in the nearby Hurricane Cliffs. Gypsiferous soil and rock are subject to dissolution which can damage foundations and create sinkholes. The principal formations in the region affected by dissolution of carbonate are the Kaibab and Toroweap Formations; both formations have developed sinkholes where crossed by perennial streams. Soil piping is

Updating the Geologic Barcodes for South China: Discovery of Late Archean Banded Iron Formations in the Yangtze Craton.

Science.gov (United States)

Ye, Hui; Wu, Chang-Zhi; Yang, Tao; Santosh, M; Yao, Xi-Zhu; Gao, Bing-Fei; Wang, Xiao-Lei; Li, Weiqiang

2017-11-08

Banded iron formations (BIFs) in Archean cratons provide important "geologic barcodes" for the global correlation of Precambrian sedimentary records. Here we report the first finding of late Archean BIFs from the Yangtze Craton, one of largest Precambrian blocks in East Asia with an evolutionary history of over 3.3 Ga. The Yingshan iron deposit at the northeastern margin of the Yangtze Craton, displays typical features of BIF, including: (i) alternating Si-rich and Fe-rich bands at sub-mm to meter scales; (ii) high SiO 2  + Fe 2 O 3total contents (average 90.6 wt.%) and Fe/Ti ratios (average 489); (iii) relative enrichment of heavy rare earth elements and positive Eu anomalies (average 1.42); (iv) and sedimentary Fe isotope compositions (δ 56 Fe IRMM-014 as low as -0.36‰). The depositional age of the BIF is constrained at ~2464 ± 24 Ma based on U-Pb dating of zircon grains from a migmatite sample of a volcanic protolith that conformably overlied the Yingshan BIF. The BIF was intruded by Neoproterozoic (805.9 ± 4.7 Ma) granitoids that are unique in the Yangtze Craton but absent in the North China Craton to the north. The discovery of the Yingshan BIF provides new constraints for the tectonic evolution of the Yangtze Craton and has important implications in the reconstruction of Pre-Nuna/Columbia supercontinent configurations.

The Mountains of Io: Global and Geological Perspectives from Voyager and Galileo

Science.gov (United States)

Schenk, Paul; Hargitai, Henrik; Wilson, Ronda; McEwen, Alfred; Thomas, Peter; Bredekamp, Joe (Technical Monitor)

2001-01-01

To search for local and global scale geologic associations that may be related to the internal dynamics of Io, we have completed a global catalog of all mountains and volcanic centers. We have identified 115 mountain structures (covering approx. 3% of the surface) and 541 volcanic centers, including paterae (calderas and dark spots) and shield volcanoes. The average length of an Ionian mountain is 157 km, with the longest being 570 km. The mean height of Ionian mountains is 6.3 km, and the highest known mountain is Boosaule Montes (17.5 +/- 3 km). Five basic morphologic types of mountains have been identified; mesa, plateau peak, ridge, and massif. Very few mountains bear any physical similarity. to classic volcanic landforms, but many resemble flatiron mountains on Earth and are interpreted as tilted crustal blocks. This would be consistent with the hypothesis that most mountains are thrust blocks formed as a result of compressive stresses built up in the lower crust due to the global subsidence of volcanic layers as they are buried over time. More than one mechanism may be responsible for all Ionian mountains, however. The proximity of some mountains to paterae may indicate a direct link between some mountains and volcanism, although it is not always clear which came first. In contrast to earlier studies, a pronounced bimodal pattern is observed in the global distribution of both mountains and volcanic centers. The regions of highest areal densities of volcanic centers are near the sub- and anti-Jovian regions, but are offset roughly 90deg in longitude from the two, regions of greatest concentration of mountains. This anticorrelation may indicate the overprinting of a second stress field on the global compressive stresses due to subsidence. The bimodal distribution of volcanic centers and mountains is consistent with models of asthenospheric tidal heating and internal convection developed by Tackley et al.Over regions of mantle upwelling, compressive stresses in

Major element compositions of fluid inclusions from hydrothermal vein-type deposits record eroded sedimentary units in the Schwarzwald district, SW Germany

Science.gov (United States)

Walter, Benjamin F.; Burisch, Mathias; Marks, Michael A. W.; Markl, Gregor

2017-12-01

Mixing of sedimentary formation fluids with basement-derived brines is an important mechanism for the formation of hydrothermal veins. We focus on the sources of the sediment-derived fluid component in ore-forming processes and present a comprehensive fluid inclusion study on 84 Jurassic hydrothermal veins from the Schwarzwald mining district (SW Germany). Our data derive from about 2300 fluid inclusions and reveal differences in the average fluid composition between the northern, central, and southern Schwarzwald. Fluids from the northern and southern Schwarzwald are characterised by high salinities (18-26 wt% NaCl+CaCl2), low Ca/(Ca+Na) mole ratios (0.1-0.4), and variable Cl/Br mass ratios (30-1140). In contrast, fluids from the central Schwarzwald show even higher salinities (23-27 wt% NaCl+CaCl2), higher Ca/(Ca+Na) mole ratios (0.2-0.9), and less variable Cl/Br mass ratios (40-130). These fluid compositions correlate with the nature and thickness of the now eroded sedimentary cover rocks. Compared to the northern and the southern Schwarzwald, where halite precipitation occurred during the Middle Triassic, the sedimentary basin in the central Schwarzwald was relatively shallow at this time and no halite was precipitated. Accordingly, Cl/Br ratios of fluids from the central Schwarzwald provide no evidence for the reaction of a sedimentary brine with halite, whereas those from the northern and southern Schwarzwald do. Instead, elevated Ca/(Ca+Na), high SO4 contents, and relatively low Cl/Br imply the presence of a gypsum dissolution brine during vein formation in the central Schwarzwald which agrees with the reconstructed regional Triassic geology. Hence, the information archived in fluid inclusions from hydrothermal veins in the crystalline basement has the potential for reconstructing sedimentary rocks in the former overburden.

Late Miocene magnetostratigraphy in the Mediterranean

NARCIS (Netherlands)

Langereis, C.G.

1984-01-01

Reversals of the geomagnetic field In the geological past are recorded globally in the natural remanent magnetization (NRM) of igneous and sedimentary rock sequences. The accurate and rei iable reconstruction of this record is the basis of magnetostratigraphy. The magnetostratigraphy of Late

Late Miocene magnetostratigraphy in the Mediterranean

NARCIS (Netherlands)

Langereis, C.G.

1984-01-01

Reversals of the geomagnetic field In the geological past are recorded globally in the natural remanent magnetization (NRM) of igneous and sedimentary rock sequences. The accurate and rei iable reconstruction of this record is the basis of magnetostratigraphy. The magnetostratigraphy of Late Miocene

Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

Science.gov (United States)

Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.

2016-01-01

The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares

Western Canada Sedimentary Basin competitiveness

International Nuclear Information System (INIS)

Millar, R.H.G.

1996-01-01

Recent dramatic expansion of the natural gas industry in the Western Canada Sedimentary Basin provided ample proof of the potential of this area for further development of natural gas supply. However, the inherent competitive advantages provided by the Western Canada Sedimentary Basin were said to have been offset by low netback prices resulting in poor producer economics when competitiveness is measured by availability of opportunities to find and develop gas supply at costs low enough to ensure attractive returns. Technology was identified as one of the key elements in improving basin competitiveness, but the greatest potential lies in reduced transportation costs and increased access to North American market centres. 8 figs

Reconciling late Quaternary transgressions in the Bohai Sea, China to the global sea level changes, and new linkage of sedimentary records to three astronomical rhythms

Science.gov (United States)

Yi, Liang

2013-04-01

Terminations. Science 326, 248-252. Ding, Z.L., Yu, Z.W., Rutter, N.W., Liu, T.S., 1994. Towards an orbital time scale for chinese loess deposits. Quaternary Science Reviews 13, 39-70. IOCAS (Institute of Oceanology, Chinese Academy of Sciences), 1985. Bohai Sea Geology. Science Press, Beijing, China. Liu, T., 2009. Loess and Arid Environment. Anhui Science & Techonology Press, Hefei, China. Wang, Y., Cheng, H., Edwards, R.L., An, Z., Wu, J., Chen, C.-C., Dorale, J.A., 2001. A High-Resolution Absolute-Dated Late Pleistocene Monsoon Record from Hulu Cave, China. Science 294, 2345-2348. Wang, Y., Cheng, H., Edwards, R.L., Kong, X., Shao, X., Chen, S., Wu, J., Jiang, X., Wang, X., An, Z., 2008. Millennial- and orbital-scale changes in the East Asian monsoon over the past 224,000 years. Nature 451, 1090-1093. Yi, L., Yu, H., Ortiz, J.D., Xu, X., Chen, S., Ge, J., Hao, Q., Yao, J., Shi, X., Peng, S., 2012a. Late Quaternary linkage of sedimentary records to three astronomical rhythms and the Asian monsoon, inferred from a coastal borehole in the south Bohai Sea, China. Palaeogeography, Palaeoclimatology, Palaeoecology 329-310, 101-117. Yi, L., Lai, Z.P., Yu, H.J., Xu, X.Y., Su, Q., Yao, J., Wang, X.L., Shi, X., 2012b. Chronologies of sedimentary changes in the south Bohai Sea, China: Constraints from luminescence and radiocarbon dating. Boreas, doi: 10.1111/j.1502-3885.2012.00271.x. Yi, L., Yu, H.J., Ortiz, J.D., Xu, X.Y., Qiang, X.K., Huang, H.J., Shi, X., Deng, C.L., 2012c. A reconstruction of late Pleistocene relative sea level in the south Bohai Sea, China, based on sediment grain-size analysis. Sedimentary Geology 281, 88-100. Zhao, S., Yang, G., Cang, S., Zhang, H., Huang, Q., Xia, D., Wang, Y., Liu, F., Liu, C., 1978. Transgression's stratas and shoreline changes in the south coast of Bohai Bay, China. Oceanologia et Limnologia Sinica 9, 15-25.

Sicily in its Mediterranean geological frame

Energy Technology Data Exchange (ETDEWEB)

Broquet, P.

2016-10-01

The Island of Sicily is generally considered to be the geological link between the North African Fold Belt and the Appennines, in Italy. This comes from a cylindristic meaning and is only partly exact. As a matter of fact, Sicily is essentially Greek; Ionian. Up to Middle Cretaceous time, the Sicilian area was a submerged shoal in the sea or the Panormide area, bordering the Ionian Ocean. This shoal lay between the future North African Fold Belt and the Appennines, forming an intermediate link between the Appenninic, Apulian, Panormian and Tunisian platforms. It was only during the Middle to Upper Cretaceous that the Atlantic and Ligure Oceans merged, making a continuous relationship between the Appenninic, Sicilian and North African sedimentary series. The key time periods are the Permian, Cretaceous and Oligo-Miocene periods leading to the formation of the actual Calabro-Sicilian arc. From the Permian to the present, the Sicilian geological history pertains to three oceanic domains: Ionian, Ligurian and Atlantic, of which the Ionian and Ligurian were under the influence of Tethys (Neo and Paleo-Tethys). The Tethysian identity of Sicily constitutes the major aspect of its geological history. However, the European and African plate tectonic movements complicated its structure. During the Middle Miocene subduction, southern Sicily became African, meanwhile its north-eastern part became, in Pliocene time, Maghrebian by accretion. Sicily is thus a truly geological patchwork, but its main section remains Ionian and now constitutes a link between North Africa and the Appennines. With older data, but also by means of recent results, we will replace Sicily in its Mediterranean frame, giving the mean stages of its paleogeographical and then its tectonic evolution. We will review the calabro-sicilian arc evolution from the Oligocene, developing the actual context and recalling the main fundamental play of the Numidian flysch. (Author)

Geology for Global Development: Mobilising and equipping young geologists to engage in disaster risk reduction

Science.gov (United States)

Gill, Joel

2016-04-01

Geology for Global Development (GfGD) is a not-for-profit organisation working to mobilise and equip geologists to engage in all aspects of sustainable development, including disaster risk reduction (DRR). Geologists have a crucial role to play in DRR, and the recently agreed Sendai Framework for DRR 2015-2030. This framework aims to significantly reduce loss of lives and livelihoods due to disasters. The geology community have an understanding of the Earth, its physical structure, and the processes by which it is constantly being shaped which are of particular relevance to Priorities for Action 1 and 4 noted within the Sendai Framework. Effective engagement by geologists, however, requires many skills beyond the standard geology curriculum. Cultural understanding, cross-disciplinary communication, diplomacy, community mobilization and participation, knowledge exchange, and an understanding of social science research tools are commonly necessary for effective research and engagement in the science-policy-practice interface. Topical and disciplinary knowledge, such as understanding social vulnerability, international policy frameworks and development theory are also rarely included in the education and professional training of a young geologist. Through the work of GfGD, we are training young geologists with these skills and the supporting knowledge required to make an effective contribution to reducing disaster risk, support civil society, empower communities and help to strengthen resilience. University chapters have been established in 14 major UK and Irish universities, coordinating extra-curricular seminars, workshops and discussion activities. Our work is currently focused on supporting young geologists, but we are increasingly a respected voice at international geoscience forums that gather a wide range of students and professionals. Wider (national and international) activities include conferences, placements and facilitating youth engagement in education

The distribution of uranium over Europe: Geological and environmental significance

Science.gov (United States)

Plant, J.A.; Reeder, S.; Salminen, R.; Smith, D.B.; Tarvainen, T.; de Vivo, B.; Petterson, M.G.

2003-01-01

The variation of baseline levels of uranium in soil and stream sediments over Europe is described, based on new data prepared by the Forum of European Geological Surveys (FOREGS). The samples have been collected and analysed according to the protocols established for the International Union of Geological Sciences/International Association of Geochemistry and Cosmochemistry (IUGS/IAGC) Working Group on Global Geochemical Baselines. The baseline levels of U vary between 0??21 to 53 mg kg-1 in topsoils, 0??19 to 30 mg kg-1 in subsoils and sample types, and the median concentration in all three media is approximately 2 mg kg-1. The most anomalous baseline levels occur over the Variscan orogen, especially areas into which late post-orogenic radiothermal high heat production (HHP) granites were emplaced. Spiderdiagrams based on trace element levels and rare earth element (REE) plots, confirm the association between the highest U anomalies and evolved radiothermal granites. High values are also associated with parts of the Alpine terrain especially in Slovenia, where there are historical U workings, and Southern Italy, where high values of U reflect contemporary volcanism. In contrast, much of the Caledonides of North West Europe and the Precambrian of the Baltic Shield and East European craton and its overlying sedimentary cover have very low values, generally radiation and radon potential associated with radiothermal granites. This is likely to be especially important where the granites are mineralised and have been worked historically, for example in the North West of the Iberian Peninsula where U and its decay products are likely to be more dispersed in the surface environment. The study also indicates the value of multi-element data in distinguishing between anthropogenic and naturally occurring anomalies.

The glacial geology and landscape of Strathmore and adjoining offshore zone, with especial reference to 1:10 000 scale Sheet NO76NW

OpenAIRE

Golledge, N.R.; Stoker, M.S.

2004-01-01

This report describes the Bedrock and Superficial Geology of 1:10 000 Sheet NO76NW (Craig of Garvock) within the Strathmore area of eastern Scotland. It forms part of the revision of Montrose 1:50 000 Geological Sheet (57E). Strathmore forms a low vale bounded to the north by the Highland Boundary Fault (HBF), and to the south by the Sidlaw Hills. NO76NW is underlain by a Devonian sedimentary sequence with interdigitating contemporaneous igneous sheets. The northern edge of the field-ma...

Study on characteristics of sedimentary rock at the Horonobe site (2). Report of collaboration research between CRIEPI and JAEA

International Nuclear Information System (INIS)

Oyama, Takahiro; Kiho, Kenzo; Suzuki, Koichi; Nakata, Eiji; Tanaka, Shiro; Hasegawa, Takuma; Nakata, Kotaro; Nagaoka, Toru; Nakamura, Takamichi; Fukushima, Tatsuo; Ishii, Eiichi; Kunimaru; Takanori; Hama, Katsuhiro; Iwatsuki, Teruki; Sugita, Yutaka; Yabuuchi, Satoshi; Miyahara, Shigenori; Takahashi, Kazuharu

2010-01-01

CRIEPI (Central Research Institute of Electric Power Industry) and JAEA (Japan Atomic Energy Agency) have been conducting a collaboration research to develop methodology for the characterization of geological environment since FY 2002. This report describes the results of the collaboration research in mainly from FY 2004 to FY 2008. As the collaboration research, the following research results were obtained. (1) Study on the slaking property. We discovered the spherical silica (amorphous silica) in siliceous rock (Opalin chert) between the Koetoi and Wakkanai Formation. The permeability of this chert (10 -12 m/sec) decreases to compare with near depth diatomaceous mudstone (10 -10 m/sec). This diatomaceous mudstone dose not rapidly slakes. Excavated disturbed zone(EdZ) at -140 m tunnel was estimated with drilled cores and gas flows from the tunnel wall. (2) Study on the chemical weathering of the sedimentary rock. The weathering property was investigated of mudstone at an outcrop and east shaft. Weathering profile was divided oxidized, dissolved, transition and fresh zone. Oxidation was limited to the vicinity of surface. (3) Study on the pore water extraction methodology. Sample preparation under N 2 condition before porewater squeezing to prevent oxidation showed that the squeezed porewater chemistry was affected by the sample storage period before squeezing. (4) Study on exploration method considering the physical property of the rock. The depth profile of the mechanical and permeability properties can be estimated by the results of physical logging in the borehole and laboratory measurements of core samples. (5) Study on the applicability of the controlled drilling system to the Horonobe site. The controlled drilling system was applied to the Hokushin site and the Kami-horonobe site in the Horonobe town. At the Kami-horonobe site, the system was applied to drill the Omagari fault and characterize the hydro-geology around the fault. The controlled drilling was

Geophysical investigations of geology and structure at the Martis Creek Dam, Truckee, California

Science.gov (United States)

Bedrosian, P.A.; Burton, B.L.; Powers, M.H.; Minsley, B.J.; Phillips, J.D.; Hunter, L.E.

2012-01-01

A recent evaluation of Martis Creek Dam highlighted the potential for dam failure due to either seepage or an earthquake on nearby faults. In 1972, the U.S. Army Corps of Engineers constructed this earthen dam, located within the Truckee Basin to the north of Lake Tahoe, CA for water storage and flood control. Past attempts to raise the level of the Martis Creek Reservoir to its design level have been aborted due to seepage at locations downstream, along the west dam abutment, and at the base of the spillway. In response to these concerns, the U.S. Geological Survey has undertaken a comprehensive suite of geophysical investigations aimed at understanding the interplay between geologic structure, seepage patterns, and reservoir and groundwater levels. This paper concerns the geologic structure surrounding Martis Creek Dam and emphasizes the importance of a regional-scale understanding to the interpretation of engineering-scale geophysical data. Our studies reveal a thick package of sedimentary deposits interbedded with Plio-Pleistocene volcanic flows; both the deposits and the flows are covered by glacial outwash. Magnetic field data, seismic tomography models, and seismic reflections are used to determine the distribution and chronology of the volcanic flows. Previous estimates of depth to basement (or the thickness of the interbedded deposits) was 100 m. Magnetotelluric soundings suggest that electrically resistive bedrock may be up to 2500 m deep. Both the Polaris Fault, identified outside of the study area using airborne LiDAR, and the previously unnamed Martis Creek Fault, have been mapped through the dam area using ground and airborne geophysics. Finally, as determined by direct-current resistivity imaging, time-domain electromagnetic sounding, and seismic refraction, the paleotopography of the interface between the sedimentary deposits and the overlying glacial outwash plays a principal role both in controlling groundwater flow and in the distribution of the

Astronomical calibration of the geological timescale: closing the middle Eocene gap

Science.gov (United States)

Westerhold, T.; Röhl, U.; Frederichs, T.; Bohaty, S. M.; Zachos, J. C.

2015-09-01

To explore cause and consequences of past climate change, very accurate age models such as those provided by the astronomical timescale (ATS) are needed. Beyond 40 million years the accuracy of the ATS critically depends on the correctness of orbital models and radioisotopic dating techniques. Discrepancies in the age dating of sedimentary successions and the lack of suitable records spanning the middle Eocene have prevented development of a continuous astronomically calibrated geological timescale for the entire Cenozoic Era. We now solve this problem by constructing an independent astrochronological stratigraphy based on Earth's stable 405 kyr eccentricity cycle between 41 and 48 million years ago (Ma) with new data from deep-sea sedimentary sequences in the South Atlantic Ocean. This new link completes the Paleogene astronomical timescale and confirms the intercalibration of radioisotopic and astronomical dating methods back through the Paleocene-Eocene Thermal Maximum (PETM, 55.930 Ma) and the Cretaceous-Paleogene boundary (66.022 Ma). Coupling of the Paleogene 405 kyr cyclostratigraphic frameworks across the middle Eocene further paves the way for extending the ATS into the Mesozoic.

Sedimentary Processes. Quantification Using Radionuclides

International Nuclear Information System (INIS)

Carroll, J.; Lerche, I.

2003-01-01

The advent of radionuclide methods in geochronology has revolutionized our understanding of modern sedimentary processes in aquatic systems. This book examines the principles of the method and its use as a quantitative tool in marine geology, with emphasis on the Pb-210 method. The assumptions and consequences of models and their behaviour are described providing the necessary background to assess the advantages and trade-offs involved when choosing a particular model for application. One of the purposes of this volume is to disentangle the influences of complicating factors, such as sediment flux variations, post-depositional diffusion of radionuclides, and bio-irrigation of sediments, to arrive at sediment ages and to properly assess the attendant data uncertainty. Environmental impacts of chemical, nuclear, or other waste material are of concern in a variety of areas around the world today. A number of relevant examples are included, demonstrating how dating models are useful for determining sources of contaminants and interpreting their influence on the environment. The book is set at a level so that an able student or professional should have no difficulty in following the procedures and methods developed. Each chapter includes case histories showing the strengths and weaknesses of a given procedure with respect to a data example. Included with this volume is the computer source code of a new generation of modelling tools based on inverse numerical analysis techniques. This first generation of the modelling tool is included, along with detailed instructions and examples for its use, in an appendix

Neoproterozoic-Early Paleozoic Peri-Pacific Accretionary Evolution of the Mongolian Collage System: Insights From Geochemical and U-Pb Zircon Data From the Ordovician Sedimentary Wedge in the Mongolian Altai

Science.gov (United States)

Jiang, Y. D.; Schulmann, K.; Kröner, A.; Sun, M.; Lexa, O.; Janoušek, V.; Buriánek, D.; Yuan, C.; Hanžl, P.

2017-11-01

Neoproterozoic to early Paleozoic accretionary processes of the Central Asian Orogenic Belt have been evaluated so far mainly using the geology of ophiolites and/or magmatic arcs. Thus, the knowledge of the nature and evolution of associated sedimentary prisms remains fragmentary. We carried out an integrated geological, geochemical, and zircon U-Pb geochronological study on a giant Ordovician metasedimentary succession of the Mongolian Altai Mountains. This succession is characterized by dominant terrigenous components mixed with volcanogenic material. It is chemically immature, compositionally analogous to graywacke, and marked by significant input of felsic to intermediate arc components, pointing to an active continental margin depositional setting. Detrital zircon U-Pb ages suggest a source dominated by products of early Paleozoic magmatism prevailing during the Cambrian-Ordovician and culminating at circa 500 Ma. We propose that the Ordovician succession forms an "Altai sedimentary wedge," the evolution of which can be linked to the geodynamics of the margins of the Mongolian Precambrian Zavhan-Baydrag blocks. This involved subduction reversal from southward subduction of a passive continental margin (Early Cambrian) to the development of the "Ikh-Mongol Magmatic Arc System" and the giant Altai sedimentary wedge above a north dipping subduction zone (Late Cambrian-Ordovician). Such a dynamic process resembles the tectonic evolution of the peri-Pacific accretionary Terra Australis Orogen. A new model reconciling the Baikalian metamorphic belt along the southern Siberian Craton with peri-Pacific Altai accretionary systems fringing the Mongolian microcontinents is proposed to explain the Cambro-Ordovician geodynamic evolution of the Mongolian collage system.

Geology of -30247, -35247, and -40247 Quadrangles, Southern Hesperia Planum, Mars

Science.gov (United States)

Mest, S. C.; Crown, D. A.

2010-01-01

Geologic mapping of MTM -30247, -35247, and -40247 quadrangles is being used to characterize Reull Vallis (RV) and examine the roles and timing of volatile-driven erosional and depositional processes. This study complements earlier investigations of the eastern Hellas region, including regional analyses [1-6], mapping studies of circum-Hellas canyons [7-10], and volcanic studies of Hadriaca and Tyrrhena Paterae [11-13]. Key scientific objectives include 1) characterizing RV in its "fluvial zone," and evaluating its history of formation, 2) analyzing channels in the surrounding plains and potential connections to RV, and 3) examining young, possibly sedimentary plains along RV.

Salt Marshes as Potential Indicatore of Global Climate Change

DEFF Research Database (Denmark)

Kim, Daehyun; Cairens, David; Jung, S.H.

2011-01-01

Coastal scientists postulate that salt marshes are significantly affected by dynamics of global climate. However, few studies have explicitly proposed a perspective that regards salt marshes as potential indicators of climate change. This review article evaluates the possibility of salt marshes...... as indicators of global climate change, focusing upon three major aspects: sedimentary, vegetation, and biogeochemical dynamics. The previous literature concerned with these aspects commonly argues that the primary impact of climate change on salt marshes occurs via sea-level variations, because hydrologic...... fluctuations regulate the frequency, duration, and depth of over-marsh flooding events. Sedimentary, floristic, and biogeochemical dynamics prove to be significantly influenced by sealevel changes regardless of climate zones, and hence, undoubtedly possess a potential for indicating climate signatures. However...

HYDROGEOLOGICAL SIGNIFICANCE OF GEOELECTRIC ...

African Journals Online (AJOL)

... basement complex rock and the sedimentary rock of Abeokuta formation. Thus for Ijebu-ode and its environs, a thorough geophysical survey is required before citing a borehole to guide against failure or dry hole. KEY WORDS: Aquifer, Coarse sand, Resistivity, Compacted Clay, Borehole. Global Jnl Geological Sciences.

Tracing of variabilities within a geological barrier by molecular organic geochemistry

International Nuclear Information System (INIS)

Hautevelle, Yann; Michels, Raymond; Malartre, Fabrice; Elie, Marcel; Trouiller, Alain

2007-01-01

The Callovo-Oxfordian claystones located at 500 m depth at Bure (Meuse, France) are currently being investigated by Andra (the French National Radioactive Waste Management Agency) for testing the feasibility of long-term and deep geological nuclear waste disposal. In order to evaluate its potential as a geological barrier, it is very important to study, assess and describe its physico-chemical variability. The molecular biomarker composition of 150 samples of these claystones and their surrounding limestones carry diverse information on the sources of the sedimentary organic matter, the chemistry of the depositional environment, the preservation and diagenesis conditions. It also allows assessing the degree of lateral and vertical variability of the organic matter within these sedimentary series. The abundance of unsaturated biomarkers, the distribution of steroids and hopanoids and CPI values >2 prove the thermal immaturity of the organic matter. The co-occurrence of plankton, bacteria and land plant biomarkers indicate that the organic matter is a mixture of marine and continental contributions. The data also reveal that the organic matter was deposited under oxic and open-sea conditions except for a brief event of photic zone anoxia at the beginning of the Middle Callovian. In the claystones, the geosynthesis of diasterenes is favored to the detriment of the formation of steranes, especially in smectite-rich levels, and the organic matter is rapidly isolated from oxidizing then reducing conditions after the deposition due to the protective effect of clays. On the scale investigated, the claystones are characterized by a unique molecular facies and are thus homogenous from their organic content point of view. Yet, detailed investigation of specific molecular families indicates changes related to major claystone-limestone transitions. The homogeneity of these claystones can be explained by the paleogeographic position of their depositional setting and the plane

Results from the geological surveys carried out in the Bure laboratory's shafts

International Nuclear Information System (INIS)

Rebours, Herve; Righini, Celine

2010-01-01

Document available in extended abstract form only. After the government's authorization to build and operate an underground laboratory, Andra started the investigation works in November 99 on the Meuse/Haute-Marne URL site. The Meuse/Haute-Marne URL is located at the border of the Champagne-Ardenne and Lorraine regions, on the township of Bure in the Callovo-Oxfordian clay-rich rock. On the URL site, the layer is about 135 m-thick and lies at a depth of 417 m to 552 m. The laboratory consists of two levels of experimental drifts at depths of 445 m and 490 m, respectively, with two vertical shafts crossing the 505 m-thick sedimentary cover of Kimeridgian (about 100 meters of marls and limestones), Oxfordian (about 300 meters of limestones) and Callovo-Oxfordian formations. The construction of the underground installations started in August 2000 with the sinking of the main shaft and was completed on the 27 April 2006 when it linked up with the southern drift of the laboratory. The two access shafts are sunk with a drill and blast method with steps of 2.4 to 3.1 m. A temporary support with grouted bolts and wire mesh is set immediately after the blasting and removal of the muck. The definitive concrete lining is installed about 12 to 20 m behind the face. The excavated diameter of the main shaft where the geological surveys and experiments have been undertaken is of 6 m (5 m after lining). The second shaft (auxiliary shaft for the ventilation of the URL) is sunk in a smaller diameter (5 m). The aims of the geological surveys carried out during the shaft sinking are to describe the vertical and lateral (between the two shafts) variations of the lithology, to confirm the absence of fault and the geometry of the argillaceous rocks formation. These surveys allow to characterize the natural or inducted fracturing by a sedimentary and structural follow-up of the excavation face. This follow-up was carried out every 2.4 to 3.0 meters in the shafts. During the shaft

Micro-analysis by U-Pb method using LAM-ICPMS and its applications for the evolution of sedimentary basins: the example from Brasilia Belt

International Nuclear Information System (INIS)

Pimentel, Marcio Martins; Matteini, Massimo; Junges, Sergio Luiz; Giustina, Maria Emilia Schutesky Della; Dantas, Elton Luiz; Buhn, Bernhard

2015-01-01

The U-Pb geochronological method using LAM-MC-ICPMS represents an important tool to investigate the geological evolution of sedimentary basins, as well as its geochronology, through the determination of upper limits for the depositional ages of detrital sedimentary rocks. The method has been applied in the Geochronology Laboratory of the Universidade de Brasilia, and in this study, a brief review of the provenance data for the sediments of the Neoproterozoic Brasilia Belt is presented and their significance for the evolution of the orogen is discussed. The results indicate that the Paranoa and Canastra Groups represent passive margin sequences formed along the western margin of the Sao Francisco-Congo continent. The Vazante Group presents similar provenance patterns, although Sm-Nd isotopic results suggest that its upper portions had contributions from younger (Neoproterozoic) sources, possibly from the Neoproterozoic Goias Magmatic Arc. On the other hand, metasediments of the Araxa and Ibia groups contain an important proportion of material derived from Neoproterozoic sources, demonstrating that they represent syn-orogenic basins. The provenance pattern of the Bambui Group is marked by an important Neoproterozoic component, showing that it constitutes a sedimentary sequence which is younger than 600 Ma, representing a foreland basin to the Brasilia Belt. (author)

Morphology and modern sedimentary deposits of the macrotidal Marapanim Estuary (Amazon, Brazil)

Science.gov (United States)

Araújo da Silva, Cléa; Souza-Filho, Pedro Walfir M.; Rodrigues, Suzan W. P.

2009-03-01

The northern Brazilian coast, east of the Amazon River is characterized by several macrotidal estuarine systems that harbor large mangrove areas with approximately 7600 km 2. The Marapanim Estuary is influenced by macrotidal regime with moderate waves influence. Morphologic units were investigated by using remote sensing images (i.e., Landsat-7 ETM+, RADARSAT- 1 Wide and SRTM) integrated with bathymetric data. The modern sedimentary deposits were analyzed from 67 cores collected by Vibracore and Rammkersonde systems. Analysis of morphology and surface sedimentary deposits of the Marapanim River reveal they are strongly influenced by the interaction of tidal, wave and fluvial currents. Based on these processes it was possible to recognize three distinct longitudinal facies zonation that revels the geological filling of a macrotidal estuary. The estuary mouth contain fine to medium marine sands strongly influenced by waves and tides, responsible for macrotidal sandy beaches and estuarine channel development, which are characterized by wave-ripple bedding and longitudinal cross-bedding sands. The estuary funnel is mainly influenced by tides that form wide tidal mudflats, colonized by mangroves, along the estuarine margin, with parallel laminations, lenticular bedding, root fragments and organic matter lenses. The upstream estuary contains coarse sand to gravel of fluvial origin. Massive mud with organic matter lenses, marks and roots fragments occur in the floodplain accumulates during seasonal flooding providing a slowly aggrading in the alluvial plain. This morphologic and depositional pattern show easily a tripartite zonation of a macrotidal estuary, that are in the final stage of filling.

A 3D analysis of spatial relationship between geological structure and groundwater profile around Kobe City, Japan: based on ARCGIS 3D Analyst.

Science.gov (United States)

Shibahara, A.; Tsukamoto, H.; Kazahaya, K.; Morikawa, N.; Takahashi, M.; Takahashi, H.; Yasuhara, M.; Ohwada, M.; Oyama, Y.; Inamura, A.; Handa, H.; Nakama, J.

2008-12-01

Kobe city is located on the northern side of Osaka sedimentary basin, Japan, containing 1,000-2,000 m thick Quaternary sediments. After the Hanshin-Awaji Earthquake (January 17, 1995), a number of geological and geophysical surveys were conducted in this region. Then high-temperature anomaly of groundwater accompanied with high Cl concentration was detected along fault systems in this area. In addition, dissolved He in groundwater showed nearly upper mantle-like 3He/4He ratio, although there were no Quaternary volcanic activities in this region. Some recent studies have assumed that these groundwater profiles are related with geological structure because some faults and joints can function as pathways for groundwater flow, and mantle-derived water can upwell through the fault system to the ground surface. To verify these hypotheses, we established 3D geological and hydrological model around Osaka sedimentary basin. Our primary goal is to analyze spatial relationship between geological structure and groundwater profile. In the study region, a number of geological and hydrological datasets, such as boring log data, seismic profiling data, groundwater chemical profile, were reported. We converted these datasets to meshed data on the GIS, and plotted in the three dimensional space to visualize spatial distribution. Furthermore, we projected seismic profiling data into three dimensional space and calculated distance between faults and sampling points, using Visual Basic for Applications (VBA) scripts. All 3D models are converted into VRML format, and can be used as a versatile dataset on personal computer. This research project has been conducted under the research contract with the Japan Nuclear Energy Safety Organization (JNES).

Advancements in exploration and In-Situ Recovery of sedimentary hosted uranium

International Nuclear Information System (INIS)

Märten, H.; Marsland-Smith, A.; Ross, J.; Haschke, M.; Kalka, H.; Schubert, J.

2014-01-01

This paper describes recent advancements in exploration technologies for sedimentary-hosted uranium deposits as basis for improved model-based planning and optimization of in-situ recovery (ISR). High-resolution shallow (<500 m depth) seismic in combination with refraction tomography is used for high-fidelity imaging of true-depth stratigraphy of sedimentary formations, tectonic faults and specific structures for the improved understanding of (hydro)geology in general and as potential indicator for uranium mineralization in particular. A new-generation geophysical downhole-wireline tool with pulsed neutron generator has been developed (i) to accurately measure U grade (PFN [prompt fission neutron] method with important intool corrections for systematic influences), (ii) to determine geophysical parameters including porosity, density, macroscopic neutron cross section (clay content) and deduced permeability, and (iii) to log the mineral composition (based on element-specific gamma ray spectroscopy applied to natural gamma rays as well as gamma rays from inelastic neutron scattering, thermal-neutron capture and neutron activation) – all by one tool. This new data - together with conventional geophysical and geochemical information – provides an excellent aid to the assessment of ISR feasibility, the design of wellfields and planning of wellfield operation. A new kinetic leaching model (reactive transport) has been specifically adjusted to acidic leaching conditions considering kinetic rates of the main neutralizing and redox reactions as function of both pH and oxidation potential (balance of e- acceptor species). It is used as an effective tool for predicting wellfield recovery curves, estimating chemicals’ consumption and optimizing leaching chemistry (i.e. dosage of chemicals to injection lixiviant) in dependence on mineralogical conditions (abundance of main reactants). (author)

Geologic map of the west-central Buffalo National River region, northern Arkansas

Science.gov (United States)

Hudson, Mark R.; Turner, Kenzie J.

2014-01-01

This map summarizes the geology of the west-central Buffalo National River region in the Ozark Plateaus region of northern Arkansas. Geologically, the region lies on the southern flank of the Ozark dome, an uplift that exposes oldest rocks at its center in Missouri. Physiographically, the map area spans the Springfield Plateau, a topographic surface generally held up by Mississippian cherty limestone and the higher Boston Mountains to the south, held up by Pennsylvanian rocks. The Buffalo River flows eastward through the map area, enhancing bedrock erosion of an approximately 1,600-ft- (490-m-) thick sequence of Ordovician, Mississippian, and Pennsylvanian carbonate and clastic sedimentary rocks that have been mildly deformed by a series of faults and folds. Quaternary surficial units are present as alluvial deposits along major streams, including a series of terrace deposits from the Buffalo River, as well as colluvium and landslide deposits mantling bedrock on hillslopes.

3D imaging of geological structures by R-VSP utilizing vibrations caused by shaft excavations at the Mizunami Underground Research Laboratory in Japan

Science.gov (United States)

Matsuoka, T.; Hodotsuka, Y.; Ishigaki, K.; Lee, C.

2009-12-01

Japan Atomic Energy Agency is now conducting the Mizunami Underground Research Laboratory (MIU) project. The MIU consists of two shafts (main shaft: 6.5m, ventilation shaft: 4.5m diameter) and horizontal research galleries, in sedimentary and granitic rocks at Mizunami City, Central Japan. The MIU project is a broad scientific study of the deep geological environment providing the basis for research and development for geological disposal of high level radioactive waste. One of the main goals is to establish techniques for investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. As a part of the MIU project, we carried out the Reverse-Vertical Seismic Profile (R-VSP) using vibrations from the blasting for the shaft excavations and drilling of boreholes in the horizontal research galleries and examined the applicability of this method to imaging of geological structures around underground facilities, such as the unconformity between the sedimentary rocks and the basal granite, and faults and fracture zones in the granite. R-VSP method is a seismic method utilizing the receiver arrays on surface and seismic sources underground (e.g. in boreholes). This method is advantageous in that planning of 3-dimensional surveys is easy compared with reflection seismic surveying and conventional VSP because seismic source arrays that are major constraint for conducting surveys on surface are unnecessary. The receiver arrays consist of six radial lines on surface with a central focus on the main shaft. Seven blast rounds for the main shaft excavation from GL-52.8m to GL-250m and the borehole drilling in the GL-200m horizontal research gallery were observed. Three types of data processing, conventional VSP data processing (VSP-CDP transform and VSP migration), Reflection data processing utilizing Seismic interferometry method (“Seismic interferometry”) and Reflection mapping utilizing Image Point transform method (“IP transform�

Global Warming in Geologic Time

International Nuclear Information System (INIS)

Archer, David

2008-01-01

The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, but a significant fraction of the fossil fuel CO2, ranging in published models in the literature from 20-60%, remains airborne for a thousand years or longer. Ultimate recovery takes place on time scales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste. The glacial/interglacial climate cycles demonstrate that ice sheets and sea level respond dramatically to millennial-timescale changes in climate forcing. There are also potential positive feedbacks in the carbon cycle, including methane hydrates in the ocean, and peat frozen in permafrost, that are most sensitive to the long tail of the fossil fuel CO2 in the atmosphere.

Current status of geoscientific studies being conducted by Japan Nuclear Cycle Development Institute in regard to geological disposal of high-level radioactive waste. Pt. 2. Horonobe Underground Research Center

International Nuclear Information System (INIS)

Eki, Nobuhiro; Yamazaki, Shinichi

2004-01-01

Japan Nuclear Cycle Development Institute (JNC) has been conducting two Underground Research Laboratory (URL) Projects. 'The Long-term Program for Research, Development and Utilization of Atomic Energy (Atomic Energy Commission, 2000)' states their technical and social importance for the Japan's program for the Geological Disposal (GD) of HLW and shows an expectation of earlier execution of the projects. One of the URL projects is Neogene argillaceous sedimentary formation hosted Horonobe URL Project. The aims of the Horonobe URL project are; Presenting concrete geological environment as an example of sedimentary formation, Confirming reliability of technologies for geological disposal of High-Level Radioactive Waste (HLW) by applying them to actual geological condition of sedimentary formation, Providing opportunities to experience the actual deep underground circumstance for the general public. The project is composed of six subjects; 1) development of site characterization methodology, 2) development of monitoring techniques, 3) development of engineering techniques for underground development, 4) neotectonic characterization of the area, 5) development of engineering techniques for designing, construction and operation of a repository, 6) development of safety assessment methodology. The project consists of three phases: investigations form the surface (Phase 1), investigations during construction of the underground facility (Phase 2) and researches using the facility (Phase 3). The total duration is about 20 years. From 2000, surface-based site investigations are going on. In course of the investigations, a series of geophysical surveys has been employed. Along with the town-wide investigation, an area for site-scale investigation was selected, a land for facilities construction was acquired in the area and the land preparation has started in 2003. Geological information gave more detailed and concrete figure of URL, which is composed of three shafts down to

Geological hazard monitoring system in Georgia

Science.gov (United States)

Gaprindashvili, George

2017-04-01

Georgia belongs to one of world's most complex mountainous regions according to the scale and frequency of Geological processes and damage caused to population, farmlands, and Infrastructure facilities. Geological hazards (landslide, debrisflow/mudflow, rockfall, erosion and etc.) are affecting many populated areas, agricultural fields, roads, oil and gas pipes, high-voltage electric power transmission towers, hydraulic structures, and tourist complexes. Landslides occur almost in all geomorphological zones, resulting in wide differentiation in the failure types and mechanisms and in the size-frequency distribution. In Georgia, geological hazards triggered by: 1. Activation of highly intense earthquakes; 2. Meteorological events provoking the disaster processes on the background of global climatic change; 3. Large-scale Human impact on the environment. The prediction and monitoring of Geological Hazards is a very wide theme, which involves different researchers from different spheres. Geological hazard monitoring is essential to prevent and mitigate these hazards. In past years in Georgia several monitoring system, such as Ground-based geodetic techniques, Debrisflow Early Warning System (EWS) were installed on high sensitive landslide and debrisflow areas. This work presents description of Geological hazard monitoring system in Georgia.

Geological research for public outreach and education in Lithuania

Science.gov (United States)

Skridlaite, Grazina; Guobyte, Rimante

2013-04-01

Successful IYPE activities and implementation of Geoheritage day in Lithuania increased public awareness in geology. A series of projects introducing geology to the general public and youth, supported by EU funds and local communities, were initiated. Researchers from the scientific and applied geology institutions of Lithuania participated in these projects and provided with the geological data. In one case, the Lithuanian Survey of Protected Areas supported the installation of a series of geological exhibitions in several regional and national parks. An animation demonstrating glacial processes was chosen for most of these because the Lithuanian surface is largely covered with sedimentary deposits of the Nemunas (Weichselian) glaciation. Researchers from the Lithuanian Geological Survey used the mapping results to demonstrate real glacial processes for every chosen area. In another case, 3D models showing underground structures of different localities were based on detailed geological maps and profiles obtained for that area. In case of the Sartai regional park, the results of previous geological research projects provided the possibility to create a movie depicting the ca. 2 Ga geological evolution of the region. The movie starts with the accretion of volcanic island arcs on the earlier continental margin at ca. 2 Ga and deciphers later Precambrian tectonic and magmatic events. The reconstruction is based on numerous scientific articles and interpretation of geophysical data. Later Paleozoic activities and following erosion sculptured the surface which was covered with several ice sheets in Quaternary. For educational purpose, a collection of minerals and rocks at the Forestry Institute was used to create an exhibition called "Cycle of geological processes". Forestry scientists and their students are able to study the interactions of geodiversity and biodiversity and to understand ancient and modern geological processes leading to a soil formation. An aging

Geologic map of the greater Denver area, Front Range urban corridor, Colorado

Science.gov (United States)

Trimble, Donald E.; Machette, Michael N.

1979-01-01

This digital map shows the areal extent of surficial deposits and rock stratigraphic units (formations) as compiled by Trimble and Machette from 1973 to 1977 and published in 1979 under the Front Range Urban Corridor Geology Program. Trimble and Machette compiled their geologic map from published geologic maps and unpublished geologic mapping having varied map unit schemes. A convenient feature of the compiled map is its uniform classification of geologic units that mostly matches those of companion maps to the north (USGS I-855-G) and to the south (USGS I-857-F). Published as a color paper map, the Trimble and Machette map was intended for land-use planning in the Front Range Urban Corridor. This map recently (1997-1999) was digitized under the USGS Front Range Infrastructure Resources Project. In general, the mountainous areas in the western part of the map exhibit various igneous and metamorphic bedrock units of Precambrian age, major faults, and fault brecciation zones at the east margin (5-20 km wide) of the Front Range. The eastern and central parts of the map (Colorado Piedmont) depict a mantle of unconsolidated deposits of Quaternary age and interspersed outcroppings of Cretaceous or Tertiary-Cretaceous sedimentary bedrock. The Quaternary mantle comprises eolian deposits (quartz sand and silt), alluvium (gravel, sand, and silt of variable composition), colluvium, and a few landslides. At the mountain front, north-trending, dipping Paleozoic and Mesozoic sandstone, shale, and limestone bedrock formations form hogbacks and intervening valleys.

Global Journal of Geological Sciences - Vol 7, No 1 (2009)

African Journals Online (AJOL)

The geologic setting, physico-chemical characteristics and utilization scheme of spring ... Subsurface temperatures, geothermal gradients and hydrocarbon studies in the ... Towards achieving sustainable water resources managemt in Nigeria ...

Morpho structural interpretation with SRTM data for helping the oil exploration: an example of Amazonas-Brazil sedimentary basin; Interpretacao morfoestrutural com dados SRTM no auxilio a exploracao petrolifera: um exemplo na bacia sedimentar do Amazonas

Energy Technology Data Exchange (ETDEWEB)

Almeida-Filho, Raimundo; Ibanez, Delano M. [INPE, Sao Jose dos Campos, SP (Brazil)], E-mails: rai@ltid.inpe.br, dmi77@uol.com.br; Miranda, Fernando P. de [Petrobras-CENPES, Rio de Janeiro, RJ (Brazil)], E-mail: fmiranda@petrobras.com.br

2010-01-15

The availability of digital elevation models produced by the SRTM (Shuttle Radar Topographic Mission) opened new possibilities for studies of geological remote sensing in the Amazonia, since these models enhance subtle details of the terrain and drainage system, usually masked in conventional orbital images. Using as a case study an area located in the Amazonas sedimentary basin, this article discusses an approach to use these data as an aid to oil exploration in that region. The analysis of the drainage network automatically extracted from that product, combined with altitude information provided by the digital elevation model, revealed a number of drainage anomalies, which may indicate surface expression of buried geological features. One of these drainage anomalies is located exactly within the limits of the Azulao Gas Field, and may correspond to the surface expression of the hydrocarbon trapping structures in that area. The methodological approach discussed in this study can be replicated elsewhere in the Amazonas and Solimoes sedimentary basins, which together comprise about 1,000,000 km{sup 2} covered by rainforest. (author)

Abstracts of the Annual Meeting of Planetary Geologic Mappers, San Antonio, TX, 2009

Science.gov (United States)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L.; Kelley, Michael S.

2009-01-01

Topics covered include: Geologic Mapping of the Beta-Atla-Themis (BAT) Region of Venus: A Progress Report; Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for Tectonic and Volcanic History of the North Polar Region of Venus; Preliminary Geological Map of the Fortuna Tessera (V-2) Quadrangle, Venus; Geological Map of the Fredegonde (V-57) Quadrangle, Venus; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus; Geologic Mapping of V-19; Lunar Geologic Mapping: A Preliminary Map of a Portion of the LQ-10 ("Marius") Quadrangle; Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schr dinger Basin; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars; Geologic Mapping Investigations of the Northwest Rim of Hellas Basin, Mars; Geologic Mapping of the Meridiani Region of Mars; Geology of a Portion of the Martian Highlands: MTMs -20002, -20007, -25002 and -25007; Geologic Mapping of Holden Crater and the Uzboi-Ladon-Morava Outflow System; Mapping Tyrrhena Patera and Hesperia Planum, Mars; Geologic Mapping of Athabaca Valles; Geologic Mapping of MTM -30247, -35247 and -40247 Quadrangles, Reull Vallis Region, Mars Topography of the Martian Impact Crater Tooting; Mars Structural and Stratigraphic Mapping along the Coprates Rise; Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan; Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: Second Year Results and Third Year Plan; Mars Global Geologic Mapping: About Half Way Done; New Geologic Map of the Scandia Region of Mars; Geologic Mapping of the Medusae Fossae Formation on Mars and the Northern Lowland Plains of Venus; Volcanism on Io: Insights from Global Geologic Mapping; and Planetary Geologic Mapping Handbook - 2009.

Effects of mass transfer between Martian satellites on surface geology

Science.gov (United States)

2015-12-21

suspected. Published by Elsevier Inc.1. Introduction Several features about the surface geology on the moons of Mars remain poorly understood. The grooves on...Deimos may have an effect on Phobos’ geology ; we shall attempt to estimate the magnitude of that effect in Section 4. For impacts with Mars, Phobos or...global surface geology , particularly in the 100+ Ma since the last Voltaire-sized impact. Therefore we believe it unlikely that the red veneer of

The geological and petrological studies of the subduction boundaries and suggestion for the geological future work in Japan　- How to avoid ultra-mega-earthquakes -

Science.gov (United States)

Ishii, T.

2015-12-01

The Pacific plate is surrounded by circum-Pacific active margin, along which volcanic and seismic activities are very high. Ultra-Mega-Earthquakes (=UMEs, M>9.0) are occasionally observed along the margin, where sedimentary rocks of subducting slaves contact with the accreted sedimentary rocks of subducted slaves. But, those UME have never been occured along western Pacific islandarc-trench system including Izu-Ogasawara (=Bonin)-Mariana-Yap-Palau-Philippine-Tonga-Kermadec Trenches. I assume that the geological and petrological characteristics of the subduction boundaries are very important to understand those different seismic activities. Along the above mentioned trench inner wall, especially in the southern Mariana, mantle peridotites are widely distributed. Subducting slave contacts directly with the olivine dominant mantle peridotites of subducted slave, serpentinite layer can be deposited easily under hydrous oceanic sub-bottom environment and very slippery subduction boundaries are left along the subduction zone.On the other hand, those geological evidences give us some ideas on how to avoid UMEs in the Japanese Islands along Japan Trench and Nankai Trough in future. We will be able to change artificially from normal subduction boundaries with asperity zone into slippery subduction boundaries with serpentine layer, by means of serpentine mud injection toward the subduction boundaries interior by combining the following improved drilling technologies A and B. (A) Deep Sea Drilling Vessel CHIKYU has a drilling ability to reach subduction boundary with asperity zone in the Nankai Trough. (B) Advanced drilling technology in the shale gas industry is tremendous, that is, after one vertical deep drilling, horizontal drilling towards several direction are performed, then shale gas is collected by hydraulic fracturing method. I hope that, after several generations, our posterity will be able to avoid UMEs by continuous serpentine mud injection.

Lithofacies-paleo-geography and uranium sedimentary facies in Hailar basin

International Nuclear Information System (INIS)

Qi Fucheng

1992-01-01

Cretaceous-Tertiary sedimentary paleo-structure and lithofacies-paleo-geography in Hailar Basin are described. Taking Chenqi coal field as an example, the sedimentary facies pattern of coal-bearing series characterized by alternating sedimentation of fluviatile and lacustrine-swampy facies is reconstructed. It is pointed out that this sedimentary facies not only controls the sedimentation and distribution of syngenetic uranium mineralization, but also is a favourable place that converges uranium-bearing solution and reduces and precipitates uranium for the second time in epigenetic mineralization

A quantitative geologic study of heterogeneity

International Nuclear Information System (INIS)

Davis, J.M.; Phillips, F.M.

1990-01-01

Spatial variation of hydraulic conductivity has been generally recognized as the dominant medium-dependent control on the transport and dispersion of contaminants in ground water. An empirical study focusing on the relationship between patters of sedimentology and patterns of permeability is being conducted at an outcrop of the Pliocene/Pleistocene Sierra Ladrones formation, central New Mexico. Methods of geostatistics and sedimentary basin analysis are employed to study the problem of aquifer heterogeneity. An air permeameter provides a means of obtaining extensive field measurements of air-flow rates through the sediments. These flow rates are subsequently used to characterize the permeability distribution of the outcrop. Both the geologic information and the air-flow rate data provide the basis for analysis of aquifer heterogeneity. Preliminary geologic mapping indicates that the sediments in the study area are the products of an arid fluvial/interfluvial depositional environment. Probability distribution analysis of the air-flow rate data suggests that the permeability of these sediments is log-normally distributed. The air permeability data are used to estimate variograms and correlation lengths in both the horizontal and vertical directions. At the scale of 10's of centimeters, the horizontal variograms exhibit exponential variogram behaviour . When two distinct lithologies are present, the correlation structure appears to be a nested exponential. Variogram analysis of estimated mean permeability at the scale of meters also shows evidence of a nested correlation structure in the horizontal direction and a periodic correlation structure in the vertical direction. Results of this study suggest that there is a direct connection between observable geologic structure and permeability statistics. (Author) (35 refs., 10 figs., 5 tabs.)

Reconstructing Magmatic-Hydrothermal Systems via Geologic Mapping of the Tilted, Cross-sectional Exposures of the Yerington District, Nevada

Science.gov (United States)

Dilles, J. H.; Proffett, J. M.

2011-12-01

The Jurassic Yerington batholith was cut by Miocene to recent normal faults and tilted ~90° west (Proffett, 1977). Exposures range from the volcanic environment to ~6 km depth in the batholith. Magmatic-hydrothermal fluids derived from the Luhr Hill granite and associated porphyry dikes produced characteristic porphyry copper mineralization and rock alteration (K-silicate, sericitic, and advanced argillic) in near-vertical columnar zones above cupolas on the deep granite. In addition, saline brines derived from the early Mesozoic volcanic and sedimentary section intruded by the batholith were heated and circulated through the batholith producing voluminous sodic-calcic and propylitic alteration. The magnetite-copper ore body at Pumpkin Hollow is hosted in early Mesozoic sedimentary rocks in the contact aureole of the batholith, and appears to be an IOCG type deposit produced where the sedimentary brines exited the batholith. Although many advances in understanding of Yerington have been made by lab-based geochronology and geochemistry studies, the first order igneous and hydrothermal features were recognized first in the 1960s and 1970s and are best documented by geological mapping at a variety of scales ranging from 1:500 to 1:24,000. The Anaconda technique of mapping mine benches, trenches, and drill cores was perfected here (Einaudi, 1997), and other techniques were used for surface exposures. The geologic and hydrothermal alteration maps establish that hydrothermal alteration accompanied each of several porphyry dike intrusions, and affected more than 100 km3 of rock. Both zonation in alteration mineralogy and vein orientations allow reconstruction of source areas and >5 km-long flow-paths of hydrothermal fluids through the batholith and contact aureole.

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

Science.gov (United States)

James, Noel P.; Narbonne, Guy M.; Dalrymple, Robert W.; Kurtis Kyser, T.

2005-01-01

Stellate crystals of ferroan dolomite in neritic siliciclastic and carbonate sedimentary rocks between Sturtian and Marinoan glaciations in the Mackenzie Mountains are interpreted as replaced glendonites. These pseudomorphs after ikaite indicate that shallow seawater at that time was near freezing. Stromatolites verify that paleoenvironments were in the photic zone and physical sedimentary structures such as hummocky cross-bedding confirm that the seafloor was repeatedly disturbed by storms. Glendonites within these low-latitude, continental shelf to coastal sedimentary deposits imply that global ocean water during much of Cryogenian time was likely very cold. Such an ocean would easily have cooled to yield widespread sea ice and, through positive feedback, growth of low-latitude continental glaciers. In this situation gas hydrates could have formed in shallow-water, cold shelf sediment, but would have been particularly sensitive to destabilization as a result of sea-level change. Co-occurrence of pisolites and glendonites in these rocks additionally implies that some ooids and pisoids might have been, unlike Phanerozoic equivalents, characteristic of cold-water sediments.

Tracing Biosignature Preservation of Geothermally Silicified Microbial Textures into the Geological Record.

Science.gov (United States)

Campbell, Kathleen A; Lynne, Bridget Y; Handley, Kim M; Jordan, Sacha; Farmer, Jack D; Guido, Diego M; Foucher, Frédéric; Turner, Susan; Perry, Randall S

2015-10-01

New Zealand and Argentine (Late Jurassic-Recent) siliceous hot-spring deposits (sinter) reveal preservation pathways of environmentally controlled, microbe-dominated sedimentary facies over geological time scales. Texturally distinctive, laminated to thinly layered, dense and vertically oriented, microtubular "palisade" fabric is common in low-temperature (geological events. A systematic approach was used to characterize palisade fabric in sinters of different ages to refine tools for recognizing biosignatures in extreme environments and to track their long-term preservation pathways into the geological record. Molecular techniques, scanning electron microscopy, Raman spectrometry, X-ray powder diffraction, petrography, and lipid biomarker analyses were applied. Results indicate that microbial communities vary at the micron scale and that early and rapid silicification is paramount to long-term preservation, especially where minimal postdepositional disturbance follows fossilization. Overall, it appears that the most robust biomarkers of fossil microbial activity in hot-spring deposits are their characteristic macro- and microtextures and laser micro-Raman identified carbon. Studies of Phanerozoic geothermal deposits with mineralized microbial components are relevant analogs for Precambrian geobiology because early life is commonly preserved as microbial microfossils and biofilms in silica, some of it hydrothermal in origin. Yet the diagenetic "movie" has already been run. Hence, studying younger sinters of a range of ages provides an opportunity to "play it again" and follow the varied influences on biosignatures into the deep-time geological record.

Classification Scheme for Diverse Sedimentary and Igneous Rocks Encountered by MSL in Gale Crater

Science.gov (United States)

Schmidt, M. E.; Mangold, N.; Fisk, M.; Forni, O.; McLennan, S.; Ming, D. W.; Sumner, D.; Sautter, V.; Williams, A. J.; Gellert, R.

2015-01-01

The Curiosity Rover landed in a lithologically and geochemically diverse region of Mars. We present a recommended rock classification framework based on terrestrial schemes, and adapted for the imaging and analytical capabilities of MSL as well as for rock types distinctive to Mars (e.g., high Fe sediments). After interpreting rock origin from textures, i.e., sedimentary (clastic, bedded), igneous (porphyritic, glassy), or unknown, the overall classification procedure (Fig 1) involves: (1) the characterization of rock type according to grain size and texture; (2) the assignment of geochemical modifiers according to Figs 3 and 4; and if applicable, in depth study of (3) mineralogy and (4) geologic/stratigraphic context. Sedimentary rock types are assigned by measuring grains in the best available resolution image (Table 1) and classifying according to the coarsest resolvable grains as conglomerate/breccia, (coarse, medium, or fine) sandstone, silt-stone, or mudstone. If grains are not resolvable in MAHLI images, grains in the rock are assumed to be silt sized or smaller than surface dust particles. Rocks with low color contrast contrast between grains (e.g., Dismal Lakes, sol 304) are classified according to minimum size of apparent grains from surface roughness or shadows outlining apparent grains. Igneous rocks are described as intrusive or extrusive depending on crystal size and fabric. Igneous textures may be described as granular, porphyritic, phaneritic, aphyric, or glassy depending on crystal size. Further descriptors may include terms such as vesicular or cumulate textures.

Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

Directory of Open Access Journals (Sweden)

Yadong Wang

2012-03-01

Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

The role of deep-water sedimentary processes in shaping a continental margin: The Northwest Atlantic

Science.gov (United States)

Mosher, David C.; Campbell, D.C.; Gardner, J.V.; Piper, D.J.W.; Chaytor, Jason; Rebesco, M.

2017-01-01

The tectonic history of a margin dictates its general shape; however, its geomorphology is generally transformed by deep-sea sedimentary processes. The objective of this study is to show the influences of turbidity currents, contour currents and sediment mass failures on the geomorphology of the deep-water northwestern Atlantic margin (NWAM) between Blake Ridge and Hudson Trough, spanning about 32° of latitude and the shelf edge to the abyssal plain. This assessment is based on new multibeam echosounder data, global bathymetric models and sub-surface geophysical information.The deep-water NWAM is divided into four broad geomorphologic classifications based on their bathymetric shape: graded, above-grade, stepped and out-of-grade. These shapes were created as a function of the balance between sediment accumulation and removal that in turn were related to sedimentary processes and slope-accommodation. This descriptive method of classifying continental margins, while being non-interpretative, is more informative than the conventional continental shelf, slope and rise classification, and better facilitates interpretation concerning dominant sedimentary processes.Areas of the margin dominated by turbidity currents and slope by-pass developed graded slopes. If sediments did not by-pass the slope due to accommodation then an above grade or stepped slope resulted. Geostrophic currents created sedimentary bodies of a variety of forms and positions along the NWAM. Detached drifts form linear, above-grade slopes along their crests from the shelf edge to the deep basin. Plastered drifts formed stepped slope profiles. Sediment mass failure has had a variety of consequences on the margin morphology; large mass-failures created out-of-grade profiles, whereas smaller mass failures tended to remain on the slope and formed above-grade profiles at trough-mouth fans, or nearly graded profiles, such as offshore Cape Fear.

Hydro-mechanical modelling of a shaft seal in crystalline and sedimentary host rock media using COMSOL

Energy Technology Data Exchange (ETDEWEB)

Priyanto, D.G. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

2011-07-01

Shaft seals are components of the engineered barriers system considered for closure of a Deep Geological Repository (DGR). These seals would be installed in strategic locations of the shafts, where significant fracture zones (FZ) are located and would serve to limit upward flow of groundwater from the repository level towards the surface. This paper presents the results of hydro-mechanical (HM) numerical modelling exercises to evaluate the performance of a shaft seal using a finite element computer code, COMSOL. This study considered a variety of host geological media as part of generic assessments of system evolution in a variety of environments including five hypothetical sedimentary and crystalline host rock conditions. Four simulations of a shaft seal in different sedimentary rocks were completed, including: shale with isotropic permeability; shale with anisotropic permeability; limestone with isotropic permeability; and limestone with anisotropic permeability. The other simulation was a shaft seal in crystalline rock with isotropic permeability. Two different stages were considered in these HM simulations. Stages 1 and 2 simulated the groundwater flow into an open shaft and after installation of shaft sealing components, respectively. As expected, the models were able to simulate that installation of the shaft seal limits groundwater flow through the shaft. Based on the conditions and assumptions defined for the host media and fracture features examined in this study, the following conclusions can be drawn from the results of the numerical modelling exercises. A shaft that remained open for a longer time was beneficial with respect to delaying of seal saturation because it could reduce the groundwater flow rate around the fracture zone. Delaying saturation time indicates slower movement of the groundwater or other substances that may be transported with the groundwater. The core of the shaft seal (i.e., the bentonite-sand mixture (BSM)) became fully saturated

A proposed descriptive methodology for environmental geologic (envirogeologic) site characterization

International Nuclear Information System (INIS)

Schwarz, D.L.; Snyder, W.S.

1994-01-01

We propose a descriptive methodology for use in environmental geologic (envirogeologic) site characterization. The method uses traditional sedimentologic descriptions augmented by environmental data needs, and facies analysis. Most other environmental methodologies for soil and sediment characterization use soil engineering and engineering geology techniques that classify by texture and engineering properties. This technique is inadequate for envirogeologic characterization of sediments. In part, this inadequacy is due to differences in the grain-size between the Unified soil Classification and the Udden-Wentworth scales. Use of the soil grain-size classification could easily cause confusion when attempting to relate descriptions based on this classification to our basic understanding of sedimentary depositional systems. The proposed envirogeologic method uses descriptive parameters to characterize a sediment sample, suggests specific tests on samples for adequate characterization, and provides a guidelines for subsurface facies analysis, based on data retrieved from shallow boreholes, that will allow better predictive models to be developed. This methodology should allow for both a more complete site assessment, and provide sufficient data for selection of the appropriate remediation technology, including bioremediation. 50 refs

Identifikasi Lapisan Geologi Bawah Permukaan Berdasarkan Data Geomagnetik di Sungai Logawa Banyumas

Directory of Open Access Journals (Sweden)

Sukmaji Anom Raharjo

2014-02-01

Full Text Available Identification of geological resources can be done either using surface mapping and cross sectional stratigraphy measurement or geophysical approximation beneath the earth surface. Geomagnetic exploration related to the existing of gold mineral begins with the total magnetic field intensity measurements at 173 locations was scattered in 109.196970 - 109.207580E and 7.448830 - 7.454110S. Interpretation from processing of data obtained four anomalous object, which is defined as fine-medium sandstone (χ= 0.0015 cgs units, coarse sandstone and compact (χ= 0.0035 cgs units, igneous basalt-andesite old Slamet (χ= 0.0085 cgs units, and the complex bedrock (χ= 0.0145 cgs units. The presence of gold mineralization in the rock throughout geomagnetic surveys used to identification of subsurface geological which is interpreted from the processing data that indicated the presence of gold in association with sedimentary (sandstone is often referred to as sediment-hosted.

The geological basis and the representation of spatial variability in fractured media

International Nuclear Information System (INIS)

Mazurek, M.; Gautschi, A.; Zuidema, P.

1998-01-01

Spatial variability of features and parameters relevant for contaminant transport modelling occurs on all scales of interest for the quantification of processes that govern solute migration, typically decimeters to hundreds of meters. Two types of spatial variability are distinguished, namely the internal heterogeneity of each individual water-conducting feature (e.g. the complex architecture of a fault) and the larger-scale heterogeneity that results from the groundwater flow through different types of water-conducting features along the flow-path from the repository to the discharge areas. An up-scaling procedure is required to obtain hydraulic parameters and the properties of the overall flow-path, whereas the heterogeneity of many other geologic features (geometry of flow and matrix porosity, mineralogy, etc.) can be fed directly into coupled codes that quantify radionuclide transport. The procedures needed to derive conceptual models integrating geological and hydraulic field measurements and observations at a given site are illustrated by examples from both crystalline and sedimentary rock formations. (author)

Sedimentary and mineral dust sources of dissolved iron to the world ocean

Directory of Open Access Journals (Sweden)

J. K. Moore

2008-05-01

from sinking particles; and 3 an improved sedimentary source for dissolved iron. Most scavenged iron (90% is put on sinking particles to remineralize deeper in the water column. The model-observation differences are reduced with these modifications. The improved BEC model is used to examine the relative contributions of mineral dust and marine sediments in driving dissolved-iron distributions and marine biogeochemistry. Mineral dust and sedimentary sources of iron contribute roughly equally, on average, to dissolved iron concentrations. The sedimentary source from the continental margins has a strong impact on open-ocean iron concentrations, particularly in the North Pacific. Plumes of elevated dissolved-iron concentrations develop at depth in the Southern Ocean, extending from source regions in the SW Atlantic and around New Zealand. The lower particle flux and weaker scavenging in the Southern Ocean allows the continental iron source to be advected far from sources. Both the margin sediment and mineral dust Fe sources substantially influence global-scale primary production, export production, and nitrogen fixation, with a stronger role for the dust source. Ocean biogeochemical models that do not include the sedimentary source for dissolved iron, will overestimate the impact of dust deposition variations on the marine carbon cycle. Available iron observations place some strong constraints on ocean biogeochemical models. Model results should be evaluated against both surface and subsurface Fe observations in the waters that supply dissolved iron to the euphotic zone.

A refined model of sedimentary rock cover in the southeastern part of the Congo basin from GOCE gravity and vertical gravity gradient observations

Science.gov (United States)

Martinec, Zdeněk; Fullea, Javier

2015-03-01

We aim to interpret the vertical gravity and vertical gravity gradient of the GOCE-GRACE combined gravity model over the southeastern part of the Congo basin to refine the published model of sedimentary rock cover. We use the GOCO03S gravity model and evaluate its spherical harmonic representation at or near the Earth's surface. In this case, the gradiometry signals are enhanced as compared to the original measured GOCE gradients at satellite height and better emphasize the spatial pattern of sedimentary geology. To avoid aliasing, the omission error of the modelled gravity induced by the sedimentary rocks is adjusted to that of the GOCO03S gravity model. The mass-density Green's functions derived for the a priori structure of the sediments show a slightly greater sensitivity to the GOCO03S vertical gravity gradient than to the vertical gravity. Hence, the refinement of the sedimentary model is carried out for the vertical gravity gradient over the basin, such that a few anomalous values of the GOCO03S-derived vertical gravity gradient are adjusted by refining the model. We apply the 5-parameter Helmert's transformation, defined by 2 translations, 1 rotation and 2 scale parameters that are searched for by the steepest descent method. The refined sedimentary model is only slightly changed with respect to the original map, but it significantly improves the fit of the vertical gravity and vertical gravity gradient over the basin. However, there are still spatial features in the gravity and gradiometric data that remain unfitted by the refined model. These may be due to lateral density variation that is not contained in the model, a density contrast at the Moho discontinuity, lithospheric density stratifications or mantle convection. In a second step, the refined sedimentary model is used to find the vertical density stratification of sedimentary rocks. Although the gravity data can be interpreted by a constant sedimentary density, such a model does not correspond to

Geology of the Waste Treatment Plant Seismic Boreholes

Energy Technology Data Exchange (ETDEWEB)

Barnett, D. Brent; Fecht, Karl R.; Reidel, Stephen P.; Bjornstad, Bruce N.; Lanigan, David C.; Rust, Colleen F.

2007-05-11

In 2006, the U.S. Department of Energy initiated the Seismic Boreholes Project (SBP) to emplace boreholes at the Waste Treatment Plant (WTP) site in order to obtain direct shear wave velocity (Vs) measurements and other physical property measurements in Columbia River basalt and interbedded sediments of the Ellensburg Formation. The goal was to reduce the uncertainty in the response spectra and seismic design basis, and potentially recover design margin for the WTP. The characterization effort within the deep boreholes included 1) downhole measurements of the velocity properties of the suprabasalt, basalt, and sedimentary interbed sequences, 2) downhole measurements of the density of the subsurface basalt and sediments, and 3) geologic studies to confirm the geometry of the contact between the various basalt and interbedded sediments through examination of retrieved core from the core hole and data collected through geophysical logging of each borehole. This report describes the results of the geologic studies from three mud-rotary boreholes and one cored borehole at the WTP. All four boreholes penetrated the entire Saddle Mountains Basalt and the upper part of the Wanapum Basalt where thick sedimentary interbeds occur between the lava flows. The basalt flows penetrated in Saddle Mountains Basalt included the Umatilla Member, Esquatzel Member, Pomona Member, and the Elephant Mountain Member. The underlying Priest Rapids Member of the Wanapum Basalt also was penetrated. The Ellensburg Formation sediments consist of the Mabton Interbed, the Cold Creek Interbed, the Selah Interbed, and the Rattlesnake Ridge Interbed; the Byron Interbed occurs between two flows of the Priest Rapids Member. The Mabton Interbed marks the contact between the Wanapum and Saddle Mountains Basalts. The thicknesses of the basalts and interbedded sediments were within expected limits. However, a small reverse fault was found in the Pomona Member flow top. This fault has three periods of

The 1:3M geologic map of Mercury: progress and updates

Science.gov (United States)

Galluzzi, Valentina; Guzzetta, Laura; Mancinelli, Paolo; Giacomini, Lorenza; Malliband, Christopher C.; Mosca, Alessandro; Wright, Jack; Ferranti, Luigi; Massironi, Matteo; Pauselli, Cristina; Rothery, David A.; Palumbo, Pasquale

2017-04-01

After the end of Mariner 10 mission a 1:5M geologic map of seven of the fifteen quadrangles of Mercury [Spudis and Guest, 1988] was produced. The NASA MESSENGER mission filled the gap by imaging 100% of the planet with a global average resolution of 200 m/pixel and this led to the production of a global 1:15M geologic map of the planet [Prockter et al., 2016]. Despite the quality gap between Mariner 10 and MESSENGER images, no global geological mapping project with a scale larger than 1:5M has been proposed so far. Here we present the status of an ongoing project for the geologic mapping of Mercury at an average output scale of 1:3M based on the available MESSENGER data. This project will lead to a fuller grasp of the planet's stratigraphy and surface history. Completing such a product for Mercury is an important goal in preparation for the forthcoming ESA/JAXA BepiColombo mission to aid selection of scientific targets and to provide context for interpretation of new data. At the time of this writing, H02 Victoria [Galluzzi et al., 2016], H03 Shakespeare [Guzzetta et al., 2016] and H04 Raditladi [Mancinelli et al., 2016] have been completed and H05 Hokusai [Rothery et al., 2017], H06 Kuiper [Giacomini et al., 2017], H07 Beethoven and H10 Derain [Malliband et al., 2017] are being mapped. The produced geologic maps were merged using the ESRI ArcGIS software adjusting discontinuous contacts along the quadrangle boundaries. Contact discrepancies were reviewed and discussed among the mappers of adjoining quadrangles in order to match the geological interpretation and provide a unique consistent stratigraphy. At the current stage, more than 20% of Mercury has now a complete 1:3M map and more than 40% of the planet will be covered soon by the maps that are being prepared. This research was supported by the Italian Space Agency (ASI) within the SIMBIOSYS project (ASI-INAF agreement no. I/022/10/0). References Galluzzi V. et al. (2016). Geology of the Victoria Quadrangle (H

A novel methodology improves reservoir characterization models using geologic fuzzy variables

Energy Technology Data Exchange (ETDEWEB)

Soto B, Rodolfo [DIGITOIL, Maracaibo (Venezuela); Soto O, David A. [Texas A and M University, College Station, TX (United States)

2004-07-01

One of the research projects carried out in Cusiana field to explain its rapid decline during the last years was to get better permeability models. The reservoir of this field has a complex layered system that it is not easy to model using conventional methods. The new technique included the development of porosity and permeability maps from cored wells following the same trend of the sand depositions for each facie or layer according to the sedimentary facie and the depositional system models. Then, we used fuzzy logic to reproduce those maps in three dimensions as geologic fuzzy variables. After multivariate statistical and factor analyses, we found independence and a good correlation coefficient between the geologic fuzzy variables and core permeability and porosity. This means, the geologic fuzzy variable could explain the fabric, the grain size and the pore geometry of the reservoir rock trough the field. Finally, we developed a neural network permeability model using porosity, gamma ray and the geologic fuzzy variable as input variables. This model has a cross-correlation coefficient of 0.873 and average absolute error of 33% compared with the actual model with a correlation coefficient of 0.511 and absolute error greater than 250%. We tested different methodologies, but this new one showed dramatically be a promiser way to get better permeability models. The use of the models have had a high impact in the explanation of well performance and workovers, and reservoir simulation models. (author)

Geological, geochemical, and geophysical studies by the U.S. Geological Survey in Big Bend National Park, Texas

Science.gov (United States)

Page, W.R.; Turner, K.J.; Bohannon, R.G.; Berry, M.E.; Williams, V.S.; Miggins, D.P.; Ren, M.; Anthony, E.Y.; Morgan, L.A.; Shanks, P.W.C.; Gray, J. E.; Theodorakos, P.M.; Krabbenhoft, D. P.; Manning, A.H.; Gemery-Hill, P. A.; Hellgren, E.C.; Stricker, C.A.; Onorato, D.P.; Finn, C.A.; Anderson, E.; Gray, J. E.; Page, W.R.

2008-01-01

Big Bend National Park (BBNP), Tex., covers 801,163 acres (3,242 km2) and was established in 1944 through a transfer of land from the State of Texas to the United States. The park is located along a 118-mile (190-km) stretch of the Rio Grande at the United States-Mexico border. The park is in the Chihuahuan Desert, an ecosystem with high mountain ranges and basin environments containing a wide variety of native plants and animals, including more than 1,200 species of plants, more than 450 species of birds, 56 species of reptiles, and 75 species of mammals. In addition, the geology of BBNP, which varies widely from high mountains to broad open lowland basins, also enhances the beauty of the park. For example, the park contains the Chisos Mountains, which are dominantly composed of thick outcrops of Tertiary extrusive and intrusive igneous rocks that reach an altitude of 7,832 ft (2,387 m) and are considered the southernmost mountain range in the United States. Geologic features in BBNP provide opportunities to study the formation of mineral deposits and their environmental effects; the origin and formation of sedimentary and igneous rocks; Paleozoic, Mesozoic, and Cenozoic fossils; and surface and ground water resources. Mineral deposits in and around BBNP contain commodities such as mercury (Hg), uranium (U), and fluorine (F), but of these, the only significant mining has been for Hg. Because of the biological and geological diversity of BBNP, more than 350,000 tourists visit the park each year. The U.S. Geological Survey (USGS) has been investigating a number of broad and diverse geologic, geochemical, and geophysical topics in BBNP to provide fundamental information needed by the National Park Service (NPS) to address resource management goals in this park. Scientists from the USGS Mineral Resources and National Cooperative Geologic Mapping Programs have been working cooperatively with the NPS and several universities on several research studies within BBNP

Radon exhalation from samples of Danish soils, subsoils and sedimentary rocks

International Nuclear Information System (INIS)

Korsbech, U.

1985-01-01

For some years it has been known that the ground below a house could be the major source of radon and radon daughters in the indoor air. Th amount of radon penetrating into buildings from the ground depends on several factors e.g. the amount of radon produced in the ground, the amount of cracks and holes in the foundation of buildings, and the pressure difference between the air in the ground (sol air) and the indoor air. As a first step in determining the influence of the ground below Danish buildings 60 samples of soils, subsoils, and sedimentary rocks have been measured for their exhalation rates of radon i.e. the amount of radon escaping the sample per mass unit and per second (Bq.kg -1 .s -1 or radon atoms per kg and per sec.). The results of the measurements of the radon exhalation are presented and commented, and a conclusion concerning the methods for finding geological deposits with a high radon halation rate is presented. (author)

Archaen to Recent aeolian sand systems and their sedimentary record

DEFF Research Database (Denmark)

Rodríguez-López, Juan Pedro; Clemmensen, Lars B; Lancaster, Nick

2014-01-01

The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand-sea or dunefield (erg) deposits, whereas coastal systems are ...

Natural Radioactivity of Intrusive-Metamorphic and Sedimentary Rocks of the Balkan Mountain Range (Serbia, Stara Planina

Directory of Open Access Journals (Sweden)

Sanna Masod Abdulqader

2017-12-01

Full Text Available Stara Planina (also known as the Balkan mountain range is known for numerous occurrences and deposits of uranium and associated radionuclides. It is also famous for its geodiversity. The geologic framework is highly complex. The mountain is situated between the latitudes of 43° and 44° N and the longitudes from 22°16′ to 23°00′ E. Uranium exploration and radioactivity testing on Stara Planina began back in 1948. Uranium has also been mined in the zone of Kalna, within the Janja granite intrusive. The naturally radioactive geologic units of Stara Planina are presented in detail in this paper. The main sources of radioactivity on Stara Planina can be classified as: 1. Granitic endogenous—syngenetic–epigenetic deposits and occurrences; 2. Metamorphogenic—syngenetic; and 3. Sedimentary, including occurrences of uranium deposition and fluctuation caused by water in different types of sedimentary rocks formed in a continental setting, which could be classified under epigenetic types. The area of Stara Planina with increased radioactivity (higher than 200 cps, measured by airborne gamma spectrometry, is about 380 square kilometers. The highest values of measured radioactivity and uranium grade were obtained from a sample taken from the Mezdreja uranium mine tailing dump, where 226Ra measures 2600 ± 100 Bq/kg and the uranium grade is from 76.54 to 77.65 ppm U. The highest uranium (and lead concentration, among all samples, is measured in graphitic schist with high concentrations of organic (graphitic material from the Inovska Series—99.47 ppm U and 107.69 ppm Pb. Thorium related radioactivity is the highest in granite samples from the Janja granite in the vicinity of the Mezdreja granite mine and the Gabrovnica granite mine tailing dump, and it is the same—250 ± 10 Bq/kg for 232Th, while the thorium grade varies from 30.82 to 60.27 ppm Th. In gray siltstones with a small amount of organic material, the highest radioactivity is

Geology and mineral deposits of Churchill County, Nevada

Science.gov (United States)

Willden, Ronald; Speed, Robert C.

1974-01-01

Churchill County, in west-central Nevada, is an area of varied topography and geology that has had a rather small total mineral production. The western part of the county is dominated by the broad low valley of the Carson Sink, which is underlain by deposits of Lake Lahontan. The bordering mountain ranges to the west and south are of low relief and underlain largely by Tertiary volcanic and sedimentary units. Pre-Tertiary rocks are extensively exposed east of the Carson Sink in the Stillwater Range, Clan Alpine Mountains, Augusta Mountains, and New Pass Mountains. The eastern valleys are underlain by Quaternary alluvial and lacustrine deposits contemporaneous with the western deposits of Lake Lahontan. The eastern mountain ranges are more rugged than the western ranges and have higher relief; the eastern valleys are generally narrower.

Global Journal of Geological Sciences - Vol 9, No 2 (2011)

African Journals Online (AJOL)

Preliminary geological and radiometric studies of granitoids of Zing-Monkin area, Adamawa Massif, Ne Nigeria · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. IV Haruna, DM Orazulike, AB Ofulume, 123-134 ...

Distinguishing seawater from geologic brine in saline coastal groundwater using radium-226; an example from the Sabkha of the UAE

Science.gov (United States)

Kraemer, Thomas F.; Wood, Warren W.; Sanford, Ward E.

2014-01-01

Sabkhat (Salt flats) are common geographic features of low-lying marine coastal areas that develop under hyper-arid climatic conditions. They are characterized by the presence of highly concentrated saline solutions and evaporitic minerals, and have been cited in the geologic literature as present-day representations of hyper-arid regional paleohydrogeology, paleoclimatology, coastal processes, and sedimentation in the geologic record. It is therefore important that a correct understanding of the origin and development of these features be achieved. Knowledge of the source of solutes is an important first step in understanding these features. Historically, two theories have been advanced as to the main source of solutes in sabkha brines: an early concept entailing seawater as the obvious source, and a more recent and dynamic theory involving ascending geologic brine forced upward into the base of the sabkha by a regional hydraulic gradient in the underlying formations. Ra-226 could uniquely distinguish between these sources under certain circumstances, as it is typically present at elevated activity of hundreds to thousands of Bq/m3 (Becquerels per cubic meter) in subsurface formation brines; at exceedingly low activities in open ocean and coastal water; and not significantly supplied to water from recently formed marine sedimentary framework material. The coastal marine sabkha of the Emirate of Abu Dhabi was used to test this hypothesis. The distribution of Ra-226 in 70 samples of sabkha brine (mean: 700 Bq/m3), 7 samples of underlying deeper formation brine (mean: 3416 Bq/m3), the estimated value of seawater (< 16 Bq/m3) and an estimate of supply from sabkha sedimentary framework grains (<~6 Bq/m3) provide the first direct evidence that ascending geologic brine contributes significantly to the solutes of this sabkha system.

Environmental and human impact on the sedimentary dynamic in the Rhone Delta subaquatic canyons (France-Switzerland)

Science.gov (United States)

Arantegui, A.; Corella, J. P.; Loizeau, J. L.; Anselmetti, F. S.; Girardclos, S.

2012-04-01

Deltas are very sensitive environments and highly vulnerable to variations in water discharge and the amount of suspended sediment load provided by the delta-forming currents. Human activities in the watershed, such as building of dams and irrigation ditches, or river bed deviations, may affect the discharge regime and sediment input, thus affecting delta growth. Underwater currents create deeply incised canyons cutting into the delta lobes. Understanding the sedimentary processes in these subaquatic canyons is crucial to reconstruct the fluvial evolution and human impact on deltaic environments and to carry out a geological risk assessment related to mass movements, which may affect underwater structures and civil infractructure. Recently acquired high-resolution multibeam bathymetry on the Rhone Delta in Lake Geneva (Sastre et al. 2010) revealed the complexity of the underwater morphology formed by active and inactive canyons first described by Forel (1892). In order to unravel the sedimentary processes and sedimentary evolution in these canyons, 27 sediment cores were retrieved in the distal part of each canyon and in the canyon floor/levee complex of the active canyon. Geophysical, sedimentological, geochemical and radiometric dating techniques were applied to analyse these cores. Preliminary data show that only the canyon originating at the current river mouth is active nowadays, while the others remain inactive since engineering works in the watershed occurred, confirming Sastre et al. (2010). However, alternating hemipelagic and turbiditic deposits on the easternmost canyons, evidence underflow processes during the last decades as well. Two canyons, which are located close to the Rhone river mouth, correspond to particularly interesting deeply incised crevasse channels formed when the underwater current broke through the outer bend of a meander in the proximal northern levee. In these canyons, turbidites occur in the sediment record indicating ongoing

Geologic map of the Vail West quadrangle, Eagle County, Colorado

Science.gov (United States)

Scott, Robert B.; Lidke, David J.; Grunwald, Daniel J.

2002-01-01

This new 1:24,000-scale geologic map of the Vail West 7.5' quadrangle, as part of the USGS Western Colorado I-70 Corridor Cooperative Geologic Mapping Project, provides new interpretations of the stratigraphy, structure, and geologic hazards in the area on the southwest flank of the Gore Range. Bedrock strata include Miocene tuffaceous sedimentary rocks, Mesozoic and upper Paleozoic sedimentary rocks, and undivided Early(?) Proterozoic metasedimentary and igneous rocks. Tuffaceous rocks are found in fault-tilted blocks. Only small outliers of the Dakota Sandstone, Morrison Formation, Entrada Sandstone, and Chinle Formation exist above the redbeds of the Permian-Pennsylvanian Maroon Formation and Pennsylvanian Minturn Formation, which were derived during erosion of the Ancestral Front Range east of the Gore fault zone. In the southwestern area of the map, the proximal Minturn facies change to distal Eagle Valley Formation and the Eagle Valley Evaporite basin facies. The Jacque Mountain Limestone Member, previously defined as the top of the Minturn Formation, cannot be traced to the facies change to the southwest. Abundant surficial deposits include Pinedale and Bull Lake Tills, periglacial deposits, earth-flow deposits, common diamicton deposits, common Quaternary landslide deposits, and an extensive, possibly late Pliocene landslide deposit. Landscaping has so extensively modified the land surface in the town of Vail that a modified land-surface unit was created to represent the surface unit. Laramide movement renewed activity along the Gore fault zone, producing a series of northwest-trending open anticlines and synclines in Paleozoic and Mesozoic strata, parallel to the trend of the fault zone. Tertiary down-to-the-northeast normal faults are evident and are parallel to similar faults in both the Gore Range and the Blue River valley to the northeast; presumably these are related to extensional deformation that occurred during formation of the northern end of the

Study on characteristics of sedimentary rock at the Horonobe site. Report of collaboration research between CRIEPI and JAEA

International Nuclear Information System (INIS)

Kiho, Kenzo; Oyama, Takahiro; Suzuki, Koichi; Nakata, Eiji; Tanaka, Shiro; Miyakawa, Kimio; Ishii, Eiichi; Takahashi, Kazuharu; Kunimaru, Takanori; Tsukui, Rota; Fukushima, Tatsuo; Seya, Masami; Hama, Katsuhiro; Aoki, Kazuhiro

2006-01-01

CRIEPI (Central Research Institute of Electric Power Industry) and JAEA (Japan Atomic Energy Agency) have been conducting a collaboration research to develop methodology for the characterization of geological environment since FY 2002. This report describes the results of the collaboration research in mainly FY 2003. As the collaboration research, the following research results were obtained. (1) Study on the diagenesis of the sedimentary rock of the Noegene Tertiary. The maximum burial depth of the formation can be estimated. (2) Study on the chemical weathering of the soft sedimentary rock. The acidic water can be caused by the chemical weathering of the rock in the Koetoi formation. (3) Study on the pore water extraction. The hydrochemical condition at the Horonobe site can be estimated by the results of the chemical analyses of extracted pore water, and the different pressure of the extraction results the different chloride contents of the pore water. (4) Study on exploration method considering the physical property of the rock. The depth profile of the mechanical properties can be estimated by the results of physical logging in the borehole. (5) Study on the applicability of the controlled drilling system to the Horonobe site. The controlled drilling system can be applicable to drill the directional borehole. (author)

Seismic response of the geologic structure underlying the Roman Colosseum and a 2-D resonance of a sediment valley

OpenAIRE

Mozco, P.; Rovelli, A.; Labak, P.; Malagnini, L.

1995-01-01

The seismic response of the geologic structure beneath the Colosseum is investigated using a two-dimensional modeling for a vertically incident plane SH wave. Computations indicate that the southern part of the Colosseum may be exposed to a seismic ground motion with significantly larger amplitudes, differential motion and longer duration than the northern part. because the southern part of the Colosseum is underlain by a sedimentfilled valley created by sedimentary filling of the former trib...

Inverse geothermal modelling applied to Danish sedimentary basins

Science.gov (United States)

Poulsen, Søren E.; Balling, Niels; Bording, Thue S.; Mathiesen, Anders; Nielsen, Søren B.

2017-10-01

This paper presents a numerical procedure for predicting subsurface temperatures and heat-flow distribution in 3-D using inverse calibration methodology. The procedure is based on a modified version of the groundwater code MODFLOW by taking advantage of the mathematical similarity between confined groundwater flow (Darcy's law) and heat conduction (Fourier's law). Thermal conductivity, heat production and exponential porosity-depth relations are specified separately for the individual geological units of the model domain. The steady-state temperature model includes a model-based transient correction for the long-term palaeoclimatic thermal disturbance of the subsurface temperature regime. Variable model parameters are estimated by inversion of measured borehole temperatures with uncertainties reflecting their quality. The procedure facilitates uncertainty estimation for temperature predictions. The modelling procedure is applied to Danish onshore areas containing deep sedimentary basins. A 3-D voxel-based model, with 14 lithological units from surface to 5000 m depth, was built from digital geological maps derived from combined analyses of reflection seismic lines and borehole information. Matrix thermal conductivity of model lithologies was estimated by inversion of all available deep borehole temperature data and applied together with prescribed background heat flow to derive the 3-D subsurface temperature distribution. Modelled temperatures are found to agree very well with observations. The numerical model was utilized for predicting and contouring temperatures at 2000 and 3000 m depths and for two main geothermal reservoir units, the Gassum (Lower Jurassic-Upper Triassic) and Bunter/Skagerrak (Triassic) reservoirs, both currently utilized for geothermal energy production. Temperature gradients to depths of 2000-3000 m are generally around 25-30 °C km-1, locally up to about 35 °C km-1. Large regions have geothermal reservoirs with characteristic temperatures

Radon and its decay product activities in the magmatic area and the adjacent volcano-sedimentary Intrasudetic Basin

Directory of Open Access Journals (Sweden)

D. Tchorz

2007-06-01

Full Text Available In the magmatic area of Sudetes covering the Karkonosze granite and adjacent volcano-sedimentary Intrasudetic Basin a study of atmospheric radon activity was performed by means of SSNTD Kodak LR-115. The study was completed by gamma spectrometric survey of eU and eTh determined by gamma activity of radon decay products 214Bi and 208Tl respectively. In the case of the western part of the Karkonosze granite area the radon decay products activity in the granitic basement was found to be as high as 343 Bq/kg for 214Bi and 496 Bq/kg for 208Tl respectively. Atmospheric radon content measured by means of Kodak LR115 track detector at the height of 1.5 m was found as high as 70 Bq/m3 in the regions, where no mining activities took place. However in the eastern part of the granitic massif in the proximity of abandoned uranium mine atmospheric radon content was found to be 6000 Bq/m3. In the case of sedimentary basin where sedimentary sequence of Carboniferous rocks has been penetrated by younger gases and fluids of volcanic origin uranium mineralization developed. The region known from its CO2 outburst during coal mining activity is characterized by good ventilation of the uranium enriched geological basement resulting in increased atmospheric radon activity being in average 72 Bq/m3. In the vicinity of coal mine tailing an increase up to 125 Bq/m3 can be observed. Seasonal variations of atmospheric radon content are influenced in agricultural areas by cyclic cultivation works (plough on soils of increased uranium content and in the case of post-industrial brownfields varying rates of radon exhalation from tailings due to different meteorological conditions.

Geologic map of the east half of the Lime Hills 1:250,000-scale quadrangle, Alaska

Science.gov (United States)

Gamble, Bruce M.; Reed, Bruce L.; Richter, Donald H.; Lanphere, Marvin A.

2013-01-01

This map is compiled from geologic mapping conducted between 1985 and 1992 by the U.S. Geological Survey as part of the Alaska Mineral Resource Assessment Program. That mapping built upon previous USGS work (1963–1988) unraveling the magmatic history of the Alaska–Aleutian Range batholith. Quaternary unit contacts depicted on this map are derived largely from aerial-photograph interpretation. K-Ar ages made prior to this study have been recalculated using 1977 decay constants. The east half of the Lime Hills 1:250,000-scale quadrangle includes part of the Alaska–Aleutian Range batholith and several sequences of sedimentary rocks or mixed sedimentary and volcanic rocks. The Alaska–Aleutian Range batholith contains rocks that represent three major igneous episodes, (1) Early and Middle Jurassic, (2) Late Cretaceous and early Tertiary, and (3) middle Tertiary; only rocks from the latter two episodes are found in this map area. The map area is one of very steep and rugged terrain; elevations range from a little under 1,000 ft (305 m) to 9,828 ft (2,996 m). Foot traverses are generally restricted to lowermost elevations. Areas suitable for helicopter landings can be scarce at higher elevations. Most of the area was mapped from the air, supplemented by direct examination of rocks where possible. This restricted access greatly complicates understanding some of the more complex geologic units. For example, we know there are plutons whose compositions vary from gabbro to granodiorite, but we have little insight as to how these phases are distributed and what their relations might be to each other. It is also possible that some of what we have described as compositionally complex plutons might actually be several distinct intrusions.

Investigating Coccolithophorid Biology in the Sedimentary Laboratory

Science.gov (United States)

McClelland, H. L. O.; Barbarin, N.; Beaufort, L.; Hermoso, M.; Rickaby, R. E. M.

2014-12-01

Coccolithophores are the ocean's dominant calcifying phytoplankton; they play an important, but poorly understood, role in long-term biogeochemical climatic feedbacks. Calcite producing marine organisms are likely to calcify less in a future world where higher carbon dioxide concentrations will lead to ocean acidification (OA), but coccolithophores may be the exception. In coccolithophores calcification occurs in an intracellular vesicle, where the site of calcite precipitation is buffered from the external environment and is subject to a uniquely high degree of biological control. Culture manipulation experiments mimicking the effects of OA in the laboratory have yielded empirical evidence for phenotypic plasticity, competition and evolutionary adaptation in asexual populations. However, the extent to which these results are representative of natural populations, and of the response over timescales of greater than a few hundred generations, is unclear. Here we describe a new sediment-based proxy for the PIC:POC (particulate inorganic to particulate organic carbon ratio) of coccolithophore biomass, which is equivalent to the fractional energy contribution to calcification at constant pH, and a biologically meaningful measure of the organism's tendency to calcify. Employing the geological record as a laboratory, we apply this proxy to sedimentary material from the southern Pacific Ocean to investigate the integrated response of real ancient coccolithophore populations to environmental change over many thousands of years. Our results provide a new perspective on phenotypic change in real populations of coccolithophorid algae over long timescales.

Evolution of the global water cycle on Mars: The geological evidence

Science.gov (United States)

Baker, V. R.; Gulick, V. C.

1993-01-01

The geological evidence for active water cycling early in the history of Mars (Noachian geological system or heavy bombardment) consists almost exclusively of fluvial valley networks in the heavily cratered uplands of the planet. It is commonly assumed that these landforms required explanation by atmospheric processes operating above the freezing point of water and at high pressure to allow rainfall and liquid surface runoff. However, it has also been documented that nearly all valley networks probably formed by subsurface outflow and sapping erosion involving groundwater outflow prior to surface-water flow. The prolonged ground-water flow also requires extensive water cycling to maintain hydraulic gradients, but is this done via rainfall recharge, as in terrestrial environments?

Late quaternary geology in Desaguadero river basin, San Luis, Argentina

International Nuclear Information System (INIS)

Chiesa, J.; Strasser, E.; Gomez, D.; De Miguel, T.

2007-01-01

Absolute radiocarbon datings of the sedimentary successions have come to knowledge enabling us to distinguish the Pleistocene deposits from the supra-lying Holocene ones. A palaeo-environmental evolution is proposed considering climatic fluctuations at the time, their relation with the river unloadings of the Andean glaciers and that proposed for the palaeo-lake of Salina del Bebedero. Sediments are described on the basis of a detailed field sampling, textural analysis (sieved and Bouyoucos) and laboratory geo-chemicals. Their interpretation of the geologic evolution is considered to be very important since it is the only river course on this arid-semi-arid region linked to the reduction of glaciers in the Andes. The sedimentary succession is dominated by high percentages of laminated limes and with green-yellowish to greyish-brown-reddish tones deposited in watery environments of low energy such as lacustrine basins and extended plains of flood, which is why the evolution of the deposit is characterized by the contrast of the values of insolubles (clastic sediment and carbonate) versus solubles (insoluble saline). The climatic cycles dominant and proposed for the center-east Argentine region are identified considering the influence of Andean glaciers on the river systems and the water balances in plain semi-arid environments. (author)

The geological basis and the representation of spatial variability in sedimentary heterogeneous media

International Nuclear Information System (INIS)

Cliffe, K.A.; Franklin, D.J.; Jones, P.I.R.; Macleod, E.J.; Porter, J.D.

1998-01-01

The impact of different conceptual models was investigated of the heterogeneity of the Sherwood Sandstone Group (SSG) at Sellafield on calculations of flow and transport. Detailed models of the heterogeneity of the Undifferentiated St Bees Sandstone (USBS) of the SSG were produced. The models took into account directly the geological structures at the facies level. The software package STORM (STOchastic Reservoir Modelling), was used to construct the models. The data required by the model are those that characterise the geometry of the channel bodies and the properties of the various sub-facies within the channels. It was found that for the case in which all of the variability was within channels, the larger scale permeabilities did not exhibit any significant correlation structure. The up-scaled effective permeabilities also exhibited correlation lengths that were comparable with the channel dimensions. Flow and transport calculations were also performed on 90 realizations of a detailed facies scale three-dimensional representation of a larger block of the USBS. The results are broadly consistent with the analytical results for transport through a random permeability field. (R.P.)

Predicting multi-scale relationships between geomorphology and bedrock geology of the rocky intertidal in Central and Northern California

Science.gov (United States)

Wheeler, A.; Aiello, I. W.

2014-12-01

Substratum geology is fundamental in shaping rocky shore morphology. Specific lithologies have various responses to wave action, tectonic features (e.g. fractures, faults) and sedimentary structures (e.g. bedding), creating distinctive weathering profiles. Along with local oceanography and climate forcing, different rock substrata create coastal morphologies that can vary distinctly between scales, ranging from mm to km. Despite the complexity of the system, qualitative observations show coastal areas with similar rock types share similar geomorphologies. Thus, a statistic relationship between geomorphology (expressed for instance by surface parameter rugosity) and geology can be envisaged. There are multiple benefits of finding such a relationship, as rocky intertidal geomorphology can be an important determinant in which organisms can settle, grow, and survive in near shore communities: allowing the prediction of geomorphologic parameters determining coastal ecology solely based on substratum geology, a crucial aspect in guiding the selection of marine protected areas. This study presents preliminary results of multi-scale geospatial surveys (cm to tens of meters) of rocky intertidal outcrops from Central to Northern California using a Terrestrial Laser Scanner. The outcrops investigated are representative of the most common igneous and sedimentary rocks in California (granitoids, conglomerates, sandstones, mudstones) and metamorphic units. The statistical analysis of the survey data support the hypothesis that surface properties can change significantly with changing scale, each rock type having distinct surface characteristics which are similar to comparable lithologies exposed at different locations. These scale dependent variations are controlled by different lithologic and structural characteristics of the outcrop in question. Our data also suggests lithologic variability within a rock unit could be a very significant factor in controlling changes in

Development of the U.S. Geological Survey's PAGER system (Prompt Assessment of Global Earthquakes for Response)

Science.gov (United States)

Wald, D.J.; Earle, P.S.; Allen, T.I.; Jaiswal, K.; Porter, K.; Hearne, M.

2008-01-01

The Prompt Assessment of Global Earthquakes for Response (PAGER) System plays a primary alerting role for global earthquake disasters as part of the U.S. Geological Survey’s (USGS) response protocol. We provide an overview of the PAGER system, both of its current capabilities and our ongoing research and development. PAGER monitors the USGS’s near real-time U.S. and global earthquake origins and automatically identifies events that are of societal importance, well in advance of ground-truth or news accounts. Current PAGER notifications and Web pages estimate the population exposed to each seismic intensity level. In addition to being a useful indicator of potential impact, PAGER’s intensity/exposure display provides a new standard in the dissemination of rapid earthquake information. We are currently developing and testing a more comprehensive alert system that will include casualty estimates. This is motivated by the idea that an estimated range of possible number of deaths will aid in decisions regarding humanitarian response. Underlying the PAGER exposure and loss models are global earthquake ShakeMap shaking estimates, constrained as quickly as possible by finite-fault modeling and observed ground motions and intensities, when available. Loss modeling is being developed comprehensively with a suite of candidate models that range from fully empirical to largely analytical approaches. Which of these models is most appropriate for use in a particular earthquake depends on how much is known about local building stocks and their vulnerabilities. A first-order country-specific global building inventory has been developed, as have corresponding vulnerability functions. For calibrating PAGER loss models, we have systematically generated an Atlas of 5,000 ShakeMaps for significant global earthquakes during the last 36 years. For many of these, auxiliary earthquake source and shaking intensity data are also available. Refinements to the loss models are ongoing

Geological Study and Regional Development of Mamberamo Raya Disctrict of Papua Province, Indonesia

Science.gov (United States)

Tonggiroh, Adi; Asri Jaya, HS; Ria Irfan, Ulva

2018-02-01

The goverment of Mamberamo Raya district was established through Act No. 19 of 2007 dated 15 March 2007 as part of the administrative area of Papua Province. The administrative age of this district is relatively young requires hard work of all components in facing development challenges so that necessary strategic steps of vision and mission of regional development to achieve ideal conditions of spatial which as direction of the desired embodiment in the future. Regional development covers all technical aspects including the geological aspect that the area is located on the morphology of the mountains and Mamberamo watershed. Strategic steps require policy as an action to achieve the goal with the elaboration of operational steps to realize the welfare of peoples equally and sustainably according to the potential physiogeography of Mamberamo watershed. The geological aspect as the consideration of technical that this region belongs to the regional tectonic which is divided into the difference of fault in the north there is Yapen fault and in the south is Mamberamo-Gauttier Fault and also a consideration on the stratigraphic structure of various rock types including the dominance of sedimentary rocks. This study examines geological aspects as an element of earth science in spatial planning in Mamberamo district, especially Kasonaweja and Burmeso. The analysis is presented based on field data, in the form of geographical map data of geological structure, geological map, and earthquake data described by cluster pattern indicating regional motion relationship and rock characteristics that make up Mamberamo watershed. It finds land characteristics controlled by geological structures, rock arrangements and landforms in response to landslide, flood and seismic changes.

Laboratory electrical resistivity analysis of geologic samples from Fort Irwin, California: Chapter E in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

Science.gov (United States)

Bloss, Benjamin R.; Bedrosian, Paul A.

2015-01-01

Correlating laboratory resistivity measurements with geophysical resistivity models helps constrain these models to the geology and lithology of an area. Throughout the Fort Irwin National Training Center area, 111 samples from both cored boreholes and surface outcrops were collected and processed for laboratory measurements. These samples represent various lithologic types that include plutonic and metamorphic (basement) rocks, lava flows, consolidated sedimentary rocks, and unconsolidated sedimentary deposits that formed in a series of intermountain basins. Basement rocks, lava flows, and some lithified tuffs are generally resistive (≥100 ohm-meters [Ω·m]) when saturated. Saturated unconsolidated samples are moderately conductive to conductive, with resistivities generally less than 100 Ω·m, and many of these samples are less than 50 Ω·m. The unconsolidated samples can further be separated into two broad groups: (1) younger sediments that are moderately conductive, owing to their limited clay content, and (2) older, more conductive sediments with a higher clay content that reflects substantial amounts of originally glassy volcanic ash subsequently altered to clay. The older sediments are believed to be Tertiary. Time-domain electromagnetic (TEM) data were acquired near most of the boreholes, and, on the whole, close agreements between laboratory measurements and resistivity models were found. 

Global Journal of Engineering Research

African Journals Online (AJOL)

The Global Journal of Engineering Research is aimed at promoting research in all areas of Engineering Research including Mechanical, Civil, Electrical, Chemical, Electronics, Geological etc. Visit the Global Journal Series website here: http://www.globaljournalseries.com/ ...

Lunar and Planetary Geology

Science.gov (United States)

Basilevsky, Alexander T.

2018-05-01

Lunar and planetary geology can be described using examples such as the geology of Earth (as the reference case) and geologies of the Earth's satellite the Moon; the planets Mercury, Mars and Venus; the satellite of Saturn Enceladus; the small stony asteroid Eros; and the nucleus of the comet 67P Churyumov-Gerasimenko. Each body considered is illustrated by its global view, with information given as to its position in the solar system, size, surface, environment including gravity acceleration and properties of its atmosphere if it is present, typical landforms and processes forming them, materials composing these landforms, information on internal structure of the body, stages of its geologic evolution in the form of stratigraphic scale, and estimates of the absolute ages of the stratigraphic units. Information about one body may be applied to another body and this, in particular, has led to the discovery of the existence of heavy "meteoritic" bombardment in the early history of the solar system, which should also significantly affect Earth. It has been shown that volcanism and large-scale tectonics may have not only been an internal source of energy in the form of radiogenic decay of potassium, uranium and thorium, but also an external source in the form of gravity tugging caused by attractions of the neighboring bodies. The knowledge gained by lunar and planetary geology is important for planning and managing space missions and for the practical exploration of other bodies of the solar system and establishing manned outposts on them.

PREDICTED SEDIMENTARY SECTION OF SUBGLACIAL LAKE VOSTOK

Directory of Open Access Journals (Sweden)

G. I. Leychenkov

2012-01-01

Full Text Available In early February 2012, the drill hole at the Vostok Station encountered theLakeVostokwater. This step is important to study the lake composition including possible microbial life and to model subglacial environments however, the next ambitious target of the Vostok Drilling Project is sampling of bottom sediments, which contain the unique record of ice sheet evolution and environmental changes in centralAntarcticafor millions of years. In this connection, the forecast of sedimentary succession based on existing geophysical data, study of mineral inclusions in the accretion ice cores and tectonic models is important task. Interpretation of Airborne geophysical data suggests thatLakeVostokis the part of spacious rift system, which exists at least from Cretaceous. Reflection and refraction seismic experiments conducted in the southern part ofLakeVostokshow very thin (200–300 m stratified sedimentary cover overlying crystalline basement with velocity of 6.0–6.2 km/s. At present, deposition in southernLakeVostokis absent and similar conditions occurred likely at least last3 m.y. when ice sheet aboveLakeVostokchanged insignificantly. It can be also inferred that from the Late Miocene the rate of deposition inLakeVostokwas extremely low and so the most of sedimentary section is older being possibly of Oligocene to early to middle Miocene age when ice sheet oscillated and deposition was more vigorous. If so, the sampling of upper few meters of this condensed section is very informative in terms of history of Antarctic glaciation. Small thickness of sedimentary cover raises a question about existence of lake (rift depression during preglacial and early glacial times.

Study on investigation and evaluation methods of deep seated sedimentary rocks. Chemical weathering, pore water squeezing and relationships of physical properties of sedimentary rocks

International Nuclear Information System (INIS)

Oyama, Takahiro; Suzuki, Koichi

2006-01-01

Chemical weathering, porewater squeezing and physical properties for the sedimentary rocks were examined. Chemical weathering potential of rocks was described by the sulfur as a acceleration factor of weathering and carbonate contents as a neutralization factor of it. The carbonate contents in the rocks were measured accurately by the gas pressure measurement method. Pore water squeezing method was applied for the semi-hard sedimentary rocks (Opalinusclay). The chemical change of extracted pore water under high pressure conditions was estimated. Physical property of sedimentary rocks have relationship among the porosity and permeability and resistivity coefficient in the same rock types. It is possible to estimate the water permeability from the geophysical tests. (author)

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization.

Science.gov (United States)

Kim, Han Sik; Jung, Myung Chae

2012-01-01

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment.

Geologic map of the Basque-Cantabrian Basin and a new tectonic interpretation of the Basque Arc

Science.gov (United States)

Ábalos, B.

2016-11-01

A new printable 1/200.000 bedrock geological map of the onshore Basque-Cantabrian Basin is presented, aimed to contribute to future geologic developments in the central segment of the Pyrenean-Cantabrian Alpine orogenic system. It is accompanied in separate appendixes by a historic report on the precedent geological maps and by a compilation above 350 bibliographic citations of maps and academic reports (usually overlooked or ignored) that are central to this contribution. Structural scrutiny of the map permits to propose a new tectonic interpretation of the Basque Arc, implementing previously published partial reconstructions. It is presented as a printable 1/400.000 tectonic map. The Basque Arc consists of various thrust slices that can expose at the surface basement rocks (Palaeozoic to Lower Triassic) and their sedimentary cover (uppermost Triassic to Tertiary), from which they are detached by intervening (Upper Triassic) evaporites and associated rocks. The slice-bounding thrusts are in most cases reactivated normal faults active during Meso-Cenozoic sedimentation that can be readily related to basement discontinuities generated during the Hercynian orogeny.

Canada's deep geological repository for used nuclear fuel - update on the site evaluation process and interweaving of aboriginal traditional knowledge

International Nuclear Information System (INIS)

Watts, B.; Belfadhel, M.B.; Facella, J.

2015-01-01

The Nuclear Waste Management Organization (NWMO) is responsible for implementing Adaptive Phased Management (APM), the approach selected by the Government of Canada for the long-term management of used nuclear fuel generated by Canadian nuclear reactors. The ultimate objective of APM is the centralized containment and isolation of Canada's used nuclear fuel in a Deep Geological Repository (DGR) in a suitable crystalline or sedimentary rock formation. In May 2010, the NWMO initiated a nine-step site selection process to seek an informed and willing community to host Canada's deep geological repository. As of April 2015, twenty-two communities expressed interest in learning more about the project. This paper provides an update on the site evaluation process and describes the approach, methods and criteria used in the assessments, focusing on geological and community well-being studies. Engagement and field activities to interweave Aboriginal Traditional Knowledge with western science are also discussed. (author)

Long-term cyclicities in Phanerozoic sea-level sedimentary record and their potential drivers

Science.gov (United States)

Boulila, Slah; Laskar, Jacques; Haq, Bilal U.; Galbrun, Bruno; Hara, Nathan

2018-06-01

Cyclic sedimentation has varied at several timescales and this variability has been geologically well documented at Milankovitch timescales, controlled in part by climatically (insolation) driven sea-level changes. At the longer (tens of Myr) timescales connection between astronomical parameters and sedimentation via cyclic solar-system motions within the Milky Way has also been proposed, but this hypothesis remains controversial because of the lack of long geological records. In addition, the absence of a meaningful physical mechanism that could explain the connection between climate and astronomy at these longer timescales led to the more plausible explanation of plate motions as the main driver of climate and sedimentation through changes in ocean and continent mass distribution on Earth. Here we statistically show a prominent and persistent 36 Myr sedimentary cyclicity superimposed on two megacycles ( 250 Myr) in a relatively well-constrained sea-level (SL) record of the past 542 Myr (Phanerozoic eon). We also show two other significant 9.3 and 91 Myr periodicities, but with lower amplitudes. The 9.3 Myr cyclicity was previously attributed to long-period Milankovitch band based on the Cenozoic record. However, the 91 Myr cyclicity has never been observed before in the geologic record. The 250 Myr cyclicity was attributed to the Wilson tectonic (supercontinent) cycle. The 36 Myr periodicity, also detected for the first time in SL record, has previously been ascribed either to tectonics or to astronomical cyclicity. Given the possible link between amplitudes of the 36 and 250 Myr cyclicities in SL record and the potential that these periodicities fall into the frequency band of solar system motions, we suggest an astronomical origin, and model these periodicities as originating from the path of the solar system in the Milky Way as vertical and radial periods that modulate the flux of cosmic rays on Earth. Our finding of the 36 Myr SL cyclicity lends credibility

Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars

Science.gov (United States)

McLennan, S. M.; Anderson, R. B.; Bell, J. F.; Bridges, J. C.; Calef, F.; Campbell, J. L.; Clark, B. C.; Clegg, S.; Conrad, P.; Cousin, A.; Des Marais, D. J.; Dromart, G.; Dyar, M. D.; Edgar, L. A.; Ehlmann, B. L.; Fabre, C.; Forni, O.; Gasnault, O.; Gellert, R.; Gordon, S.; Grant, J. A.; Grotzinger, J. P.; Gupta, S.; Herkenhoff, K. E.; Hurowitz, J. A.; King, P. L.; Le Mouélic, S.; Leshin, L. A.; Léveillé, R.; Lewis, K. W.; Mangold, N.; Maurice, S.; Ming, D. W.; Morris, R. V.; Nachon, M.; Newsom, H. E.; Ollila, A. M.; Perrett, G. M.; Rice, M. S.; Schmidt, M. E.; Schwenzer, S. P.; Stack, K.; Stolper, E. M.; Sumner, D. Y.; Treiman, A. H.; VanBommel, S.; Vaniman, D. T.; Vasavada, A.; Wiens, R. C.; Yingst, R. A.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; Blank, Jennifer; Weigle, Gerald; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Siebach, Kirsten; Brunet, Claude; Hipkin, Victoria; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Lasue, Jérémie; Lee, Qiu-Mei; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Robert, François; Sautter, Violaine; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Fassett, Caleb; Blake, David F.; Bristow, Thomas; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Williams, Rebecca M. E.; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Wolff, Michael; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Pradler, Irina; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

2014-01-01

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

Elemental geochemistry of sedimentary rocks at Yellowknife Bay, Gale crater, Mars.

Science.gov (United States)

McLennan, S M; Anderson, R B; Bell, J F; Bridges, J C; Calef, F; Campbell, J L; Clark, B C; Clegg, S; Conrad, P; Cousin, A; Des Marais, D J; Dromart, G; Dyar, M D; Edgar, L A; Ehlmann, B L; Fabre, C; Forni, O; Gasnault, O; Gellert, R; Gordon, S; Grant, J A; Grotzinger, J P; Gupta, S; Herkenhoff, K E; Hurowitz, J A; King, P L; Le Mouélic, S; Leshin, L A; Léveillé, R; Lewis, K W; Mangold, N; Maurice, S; Ming, D W; Morris, R V; Nachon, M; Newsom, H E; Ollila, A M; Perrett, G M; Rice, M S; Schmidt, M E; Schwenzer, S P; Stack, K; Stolper, E M; Sumner, D Y; Treiman, A H; VanBommel, S; Vaniman, D T; Vasavada, A; Wiens, R C; Yingst, R A

2014-01-24

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

Sedimentary uranium occurrences in Eastern Europe with special reference to sandstone formations

International Nuclear Information System (INIS)

Barthel, F.; Hahn, L.

1985-01-01

Sedimentary uranium deposits, especially in sandstones, play an important role in uranium mining in Eastern Europe. The paper reviews recent publications on uranium occurrences in sandstone formations in the German Democratic Republic, Poland, CSSR, Hungary, Romania, Bulgaria and Albania. The uranium deposits in sandstones in Yugoslavia are described in a separate paper in this volume. Sandstone deposits of the USSR are not reviewed. Uranium mineralizations occur in sandstones from Ordovician to Tertiary age. Major deposits are developed in Upper Carboniferous sandstones in association with coal (GDR, Poland), in Permian strata (CSSR, Hungary, Romania), in Cretaceous sandstones (GDR, CSSR), and in Tertiary sediments (CSSR). The Permian deposits can be compared with deposits of similar age in Northern Italy and Northern Yugoslavia. Roll-type orebodies are developed in some of the Cenomanian sandstones. Tertiary deposits are mainly associated with lignites. Uranium deposits in sandstones of Albania and Bulgaria are not described in the literature. Geologic similarities with sandstone basins in adjacent countries suggest the presence of uranium mineralizations in Permian, Lower Triassic, and Tertiary sandstones. (author)

Application of Remote Sensing in Geological Mapping, Case Study al Maghrabah Area - Hajjah Region, Yemen

Science.gov (United States)

Al-Nahmi, F.; Saddiqi, O.; Hilali, A.; Rhinane, H.; Baidder, L.; El arabi, H.; Khanbari, K.

2017-11-01

Remote sensing technology plays an important role today in the geological survey, mapping, analysis and interpretation, which provides a unique opportunity to investigate the geological characteristics of the remote areas of the earth's surface without the need to gain access to an area on the ground. The aim of this study is achievement a geological map of the study area. The data utilizes is Sentinel-2 imagery, the processes used in this study, the OIF Optimum Index Factor is a statistic value that can be used to select the optimum combination of three bands in a satellite image. It's based on the total variance within bands and correlation coefficient between bands, ICA Independent component analysis (3, 4, 6) is a statistical and computational technique for revealing hidden factors that underlie sets of random variables, measurements, or signals, MNF Minimum Noise Fraction (1, 2, 3) is used to determine the inherent dimensionality of image data to segregate noise in the data and to reduce the computational requirements for subsequent processing, Optimum Index Factor is a good method for choosing the best band for lithological mapping. ICA, MNF, also a practical way to extract the structural geology maps. The results in this paper indicate that, the studied area can be divided into four main geological units: Basement rocks (Meta volcanic, Meta sediments), Sedimentary rocks, Intrusive rocks, volcanic rocks. The method used in this study offers great potential for lithological mapping, by using Sentinel-2 imagery, the results were compared with existing geologic maps and were superior and could be used to update the existing maps.

Soil Structure Evaluation Across Geologic Transition Zones Using 2D Electrical Resistivity Imaging Technique

Directory of Open Access Journals (Sweden)

Geraldine C Anukwu

2017-06-01

Full Text Available This study utilizes the electrical resistivity values obtained using 2-D Electrical resistivity imaging (ERI technique to evaluate the subsurface lithology across different geological units. The primary objective was to determine the effect of subsurface lithology on the integrity of a road pavement, which had developed cracks and potholes at various locations. The dipole-dipole configuration was utilized and a total of nine traverses were established in the study area, whose geology cuts across both the basement and sedimentary complexes. The inverted resistivity section obtained showed significant variation in resistivity along established traverses and also across the different rock units, with the resistivity value ranging from about 4 ohm-m to greater than 7000 ohm- m. The lithology as interpreted from the resistivity section revealed the presence topsoil, clay, sandy clay, sand, sand stones/basement rocks, with varying vertical and horizontal arrangements to a depth of 40m. Results suggest that the geologic sequence and structure might have contributed to the observed pavement failure. The capability of the 2D ERI as an imaging tool is observed, especially across the transition zones as depicted in this study. The study further stressed the ability of this technique if properly designed and implemented, to be capable of providing a wealth of information that could complement other traditional geotechnical and geologic techniques.

Modeling study on geological environment at Horonobe URL site

International Nuclear Information System (INIS)

Shimo, Michito; Yamamoto, Hajime; Kumamoto, Sou; Fujiwara, Yasushi; Ono, Makoto

2005-02-01

The Horonobe underground research project has been operated by Japan Nuclear Cycle Development Institute to study the geological environment of sedimentary rocks in deep underground. The objectives of this study are to develop a geological environment model, which incorporate the current findings and the data obtained through the geological, geophysical, and borehole investigations at Horonobe site, and to predict the hydrological and geochemical impacts caused by the URL shaft excavation to the surrounding area. A three-dimensional geological structure model was constructed, integrating a large-scale model (25km x 15km) and a high-resolution site-scale model (4km x 4km) that have been developed by JNC. The constructed model includes surface topography, geologic formations (such as Yuchi, Koetoi, Wakkanai, and Masuporo Formations), and two major faults (Ohomagari fault and N1 fault). In hydrogeological modeling, water-conductive fractures identified in Wakkanai Formation are modeled stochastically using EHCM (Equivalent Heterogeneous Continuum Model) approach, to represent hydraulic heterogeneity and anisotropy in the fractured rock mass. Numerical code EQUIV FLO (Shimo et al., 1996), which is a 3D unsaturated-saturated groundwater simulator capable of EHCM, was used to simulate the regional groundwater flow. We used the same model and the code to predict the transient hydrological changes caused by the shaft excavations. Geochemical data in the Horonobe site such as water chemistries, mineral compositions of rocks were collected and summarized into digital datasets. M3 (Multivariate, Mixing and Mass-balance) method developed by SKB (Laaksoharju et al., 1999) was used to identify waters of different origins, and to infer the mixing ratio of these end-members to reproduce each sample's chemistry. Thermodynamic code such as RHREEQC, GWB, and EQ3/6 were used to model chemical reactions that explain the present minerals and aqueous concentrations observed in the site

Sedimentary structures of tidal flats

Indian Academy of Sciences (India)

Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone ...

Mineralogy of selected sedimentary interbeds at or near the Idaho National Engineering Laboratory, Idaho

International Nuclear Information System (INIS)

Reed, M.F.; Bartholomay, R.C.

1994-08-01

The US Geological Survey's (USGS) Project Office at the Idaho National Engineering Laboratory (INEL) analyzed 66 samples from sedimentary interbed cores during a 38-month period beginning in October 1990 to determine bulk and clay mineralogy. These cores had been collected from 19 sites in the Big Lost River Basin, 2 sites in the Birch Creek Basin, and 1 site in the Mud Lake Basin, and were archived at the USGS lithologic core library at the INEL. Mineralogy data indicate that core samples from the Big Lost River Basin have larger mean and median percentages of quartz, total feldspar, and total clay minerals, but smaller mean and median percentages of calcite than the core samples from the Birch Creek Basin. Core samples from the Mud Lake Basin have abundant quartz, total feldspar, calcite, and total clay minerals. 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

Sedimentary environments: processes, facies, and stratigraphy

National Research Council Canada - National Science Library

Reading, H. G; Reading, Harold G

1996-01-01

... and chemical systems, 6 2.1.2 Climate, 7 2.1.3 Tectonic movements and subsidence, 11 2.1.4 Sea-level changes, 11 2.1.5 Milankovitch processes and orbital forcing, 14 2.1.6 Intrinsic sedimentary processes,...

Combined NLCG/SBI magnetotelluric data inversion for recognition of complex geological structures

International Nuclear Information System (INIS)

Michal Stefaniuk

2009-01-01

Complete text of publication follows. Geological interpretation of magnetotelluric data is a subject of some misunderstandings. Simplified geometrically and well contrasted in resistivity models do not response for real geological environment. The aim of outstripping magnetotelluric works widely made in Polish Outer Carpathians, is general structural and lithological recognising of geological environment and distinguishing of areas where oil prospection will be projected. The geological medium is formed by sedimentary formations, strongly deformed and containing relatively thin layers with essentially differentiated parameters, overlying rather flat, high resistivity basement. Application of simplified strongly contrasted interpretation model with fluently changing parameters gives frequently results not corresponding with geological reality. Presented analysis is based on surveys located in marginal zone of Carpathianst in the area relatively well recognised, where interpreted structural and lithologic model rather well reflects real geological medium. Then, it was used as reference model for obtained results of MT data inversion. Magnetotelluric continuous profiling located along reflection seismic profile, between two deep boreholes was made. Set of results of computations allows to evaluate of effectiveness of used procedures and suggest optimum way of dealing. First stage of data interpretation was based on 1D and EMAP inversion. The section was then applied as starting model for 2D NLCG inversion. Results of this method give rather generalized resistivity distribution well reflecting structure of flysch cover but not adequate for the basement. This models was applied as starting models for SBI inversion constrained by borehole data. Results of SBI procedure well reflects relatively flat complexes of the basement, but are rather unrealistic for folded flysch cover. The another NLCG inversion was computed with stabilised model of basement obtained from SBI

The sedimentary dynamics in natural and human-influenced delta channel belts

NARCIS (Netherlands)

Hobo, N.

2015-01-01

This study investigates the increased anthropogenic influence on the within-channel belt sedimentary dynamics in the Rhine delta. To make this investigation, the sedimentary dynamics within the life-cycle of a single channel belt were reconstructed for three key periods of increasing human impact,

Proceedings of the 39. Brazilian congress on geology. v. 1

International Nuclear Information System (INIS)

1996-01-01

The book presents the 39. Brazilian Congress on Geology works, occurred in Salvador, Bahia, during the period of September 1 to 6, 1996. The meeting main subject - geology and society - reflects the current change epoch. The symposiums revealed the more important actions about geosciences applications to the society in the country. The round tables, structured for the polemical subjects debates that involves the geosciences and the mineral sector crisis aspects, were achieved by several invited participants completely embraced with the subject. During the congress activities development there were some courses, technical excursions and external actions in Salvador, aiming to to show the geosciences role to the social welfare. The works were presented the following symposiums: the social value of the environment study; urban geology and geology risks; degraded areas recovery; coastal erosion; global paleoregisters; and carstic terranes geology

Geology of the Río de la Plata and the surrounding areas of Argentina and Uruguay related to the evolution of the Atlantic margin

Science.gov (United States)

Rossello, Eduardo A.; Veroslavsky, Gerardo; de Santa Ana, Héctor; Rodríguez, Pablo

2018-04-01

An integrated study of geological and geophysical data of the Río de la Plata region and its relation to the evolution of the Atlantic passive margin is herein described. This characterization is based on the available geological and geophysical information and on the correlation of the southern end of the best-known Santa Lucía Basin in Uruguay to the Salado Basin in Argentina, and their connection through the Quilmes Trough. Furthermore, a new Meso-Cenozoic depocenter is characterized and identified as Recalada Trough, subparallely aligned to the Quilmes Trough and separated from it by the Magdalena-Montevideo High. Both sedimentary fillings present ENE-WSW trending main axes and reach an average thickness of almost 2000 m. This suggests an evolution from a triple junction where interconnected extensional arms developed, which have had common Mesozoic tectosedimentary histories related to the early opening of the Atlantic Ocean. Based on the geophysical and geological evidence, the previously accepted existence in the Río de la Plata of a first-order structural feature along the international border between Argentina and Uruguay, associated to an ENE-WSW trending tectonic high, identified as Martín García, is unjustified. The tectonic evolution of the Atlantic margin in front of the Río de la Plata estuary is the consequence of a long deformation history starting in the Precambrian up to recent times. Each Precambrian, Paleozoic, Mesozoic and Cenozoic tectonic scenario adds different weak trends on the continental crust, which control the evolution of the sedimentary depocenters. The presence of these tectosedimentary records influence the bathymetric control of the Río de la Plata and the dynamics of the recent estuarine deposits. The Meso-Cenozoic sedimentary infill is estimated to comprise considerable ranges of sandstones and conglomerates associated with faulted blocks of the crystalline basement, with expected petrophysical conditions oscillating in

A brief geological history of Cockspur Island at Fort Pulaski National Monument, Chatham County, Georgia

Science.gov (United States)

Swezey, Christopher S.; Seefelt, Ellen L.; Parker, Mercer

2018-03-09

Fort Pulaski National Monument is located on Cockspur Island in Chatham County, Georgia, within the Atlantic Coastal Plain province. The island lies near the mouth of the Savannah River, and consists of small mounds (hummocks), salt marshes, and sediment dredged from the river. A 1,017-foot (ft) (310-meter [m])-deep core drilled at Cockspur Island in 2010 by the U.S. Geological Survey revealed several sedimentary units ranging in age from 43 million years old to present. Sand and mud are present at drilling depths from 0 to 182 ft (56 m), limestone is present at depths from 182 ft (56 m) to 965 ft (295 m), and glauconitic sand is present at depths from 965 ft (295 m) to 1,017 ft (310 m). The limestone and the water within the limestone are referred to collectively as the Floridan aquifer system, which is the primary source of drinking water for the City of Savannah and surrounding communities. In addition to details of the subsurface geology, this fact sheet identifies the following geologic materials used in the construction of Fort Pulaski: (1) granite, (2) bricks, (3) sandstone, and (4) lime mud with oyster shells.

Potash—A vital agricultural nutrient sourced from geologic deposits

Science.gov (United States)

Yager, Douglas B.

2016-11-15

This report summarizes the primary sources of potash in the United States. Potash is an essential nutrient that, along with phosphorus and nitrogen, is used as fertilizer for growing crops. Plants require sufficient potash to activate enzymes, which in turn catalyze chemical reactions important for water uptake and photosynthesis. When potassium is available in quantities necessary for healthy plant growth, disease resistance and physical quality are improved and crop yield and shelf life are increased. Potash is a water-soluble compound of potassium formed by geologic and hydrologic processes. The principal potash sources discussed are the large, stratiform deposits that formed during retreat and evaporation of intracontinental seas. The Paradox, Delaware, Holbrook, Michigan, and Williston sedimentary basins in the United States are examples where extensive potash beds were deposited. Ancient marine-type potash deposits that are close to the surface can be mined using conventional underground mining methods. In situ solution mining can be used where beds are too deep, making underground mining cost-prohibitive, or where underground mines are converted to in situ solution mines. Quaternary brine is another source of potash that is recovered by solar evaporation in manmade ponds. Groundwater from Pleistocene Lake Bonneville (Wendover, Utah) and the present-day Great Salt Lake in Utah are sources of potashbearing brine. Brine from these sources pumped to solar ponds is evaporated and potash concentrated for harvesting, processing, and refinement. Although there is sufficient potash to meet near-term demand, the large marine-type deposits are either geographically restricted to a few areas or are too deep to easily mine. Other regions lack sources of potash brine from groundwater or surface water. Thus, some areas of the world rely heavily on potash imports. Political, economic, and global population pressures may limit the ability of some countries from securing

Geology and Design: Formal and Rational Connections

Science.gov (United States)

Eriksson, S. C.; Brewer, J.

2016-12-01

Geological forms and the manmade environment have always been inextricably linked. From the time that Upper Paleolithic man created drawings in the Lascaux Caves in the southwest of France, geology has provided a critical and dramatic spoil for human creativity. This inspiration has manifested itself in many different ways, and the history of architecture is rife with examples of geologically derived buildings. During the early 20th Century, German Expressionist art and architecture was heavily influenced by the natural and often translucent quality of minerals. Architects like Bruno Taut drew and built crystalline forms that would go on to inspire the more restrained Bauhaus movement. Even within the context of Contemporary architecture, geology has been a fertile source for inspiration. Architectural practices across the globe leverage the rationality and grounding found in geology to inform a process that is otherwise dominated by computer-driven parametric design. The connection between advanced design technology and the beautifully realized geo natural forms insures that geology will be a relevant source of architectural inspiration well into the 21st century. The sometimes hidden relationship of geology to the various sub-disciplines of Design such as Architecture, Interiors, Landscape Architecture, and Historic Preservation is explored in relation to curriculum and the practice of design. Topics such as materials, form, history, the cultural and physical landscape, natural hazards, and global design enrich and inform curriculum across the college. Commonly, these help define place-based education.

Ontario Power Generation's proposed L and ILW deep geologic repository: geo-scientific assessment

International Nuclear Information System (INIS)

Jensen, Mark; Raven, Ken; Leech, Robert

2012-01-01

Document available in extended abstract form only. The Nuclear Waste Management Organization (NWMO) on behalf of Ontario Power Generation (OPG) has conducted multi-disciplinary geo-scientific studies at the Bruce nuclear site to confirm the suitability of the site to host a proposed Deep Geologic Repository (DGR) for the long-term management of Low and Intermediate Level Radioactive Waste (L and ILW) from OPG owned or operated nuclear generating facilities. An Environmental Assessment for the proposed DGR is currently underway in accordance with the Canadian Environmental Assessment Act. Bruce nuclear site, situated 225 km northwest of Toronto on the eastern shore of Lake Huron, is underlain by an 850 m thick sedimentary sequence of Cambrian to Devonian age near-horizontally layered, weakly deformed shales, carbonates and evaporites of the Michigan Basin. Within this sedimentary pile, the proposed DGR would be excavated within the low permeability argillaceous limestone of the Cobourg Formation at a depth of 680 m, which is overlain by 200 m of Upper Ordovician shale formations (Figure 1). A key aspect of the DGR Safety Case is the predictable nature and long-term stability and integrity of the sedimentary sequence to contain and isolate L and ILW at time frames on the order of 1 Ma. Early in the project, geo-scientific studies that considered regional and site-specific public domain data sets indicated favourable geologic conditions for implementation of the DGR concept (Golder, 2003; Mazurek, 2004). Geo-scientific studies for the DGR were initiated in 2006 following decision by the Municipality of Kincardine to support the DGR concept. Geo-scientific activities were divided into two key areas; i) Site-specific geo-scientific studies of the Bruce nuclear site (i.e., Descriptive Geosphere Site Model); and ii) a Geo-synthesis to convey an understanding of past, present and future evolution of Geosphere enclosing the DGR relevant to communicating notions of

Geology and radiometry of West Macedonia (Greece)

International Nuclear Information System (INIS)

Minatidis, Demetrios G.

1984-10-01

Car borne scintillometry survey in W. Macedonia (Greece) showed that the granitic rocks of the area, the zone centered on the Tertiary volcanic rocks of Almopia zone and a large part of adjacent sediments constitute the most promising geological formations for further uranium exploration. Some Tertiary volcanic rocks in the general area centered on the Aegean plate are associated with uranium mineralization and high radioactivity. An attempt has been made to evaluate young Alpine volcanic rocks from uranium exploration point of view on a regional scale by using arithmetic mean radioactivity data from the car borne survey coverage of W. Macedonia, as well as other geological and geochemical data from numerous similar volcanic rocks of the area and other neighbouring areas. In connection with this further exploration of the Tertiary volcanic rocks of W. Macedonia is expected to reveal new uranium deposits in the area. Horizontal or gently dipping sedimentary rocks adjacent to the above mentioned volcanics have a statistical radioactivity higher than that in normal sediments, a fact that may give evidence of the existence or uranium mineralization in deeper horizons in these sediments. To make a comparison with this the existence of 134 ppm of leachable U in sediments of W. Crete Island, 20 to 30 meters below the surface, is reported where the overlying sediments exhibit also a radioactivity higher than in normal sediments. Some structural contacts, in particular the contact between the granite of Florina and the limestones of Krystallopigi (west of Florina), have locally a very high radioactivity. Also an open fault in the Achlada-Papadia area (Florina) exhibits locally a high radioactivity and a high U content. All the above mentioned geological formations are, therefore, proposed for further U exploration. (author)

Single-grain 40Ar-39Ar ages of glauconies: implications for the geologic time scale and global sea level variations

Science.gov (United States)

Smith; Evensen; York; Odin

1998-03-06

The mineral series glaucony supplies 40% of the absolute-age database for the geologic time scale of the last 250 million years. However, glauconies have long been suspected of giving young potassium-argon ages on bulk samples. Laser-probe argon-argon dating shows that glaucony populations comprise grains with a wide range of ages, suggesting a period of genesis several times longer ( approximately 5 million years) than previously thought. An estimate of the age of their enclosing sediments (and therefore of time scale boundaries) is given by the oldest nonrelict grains in the glaucony populations, whereas the formation times of the younger grains appear to be modulated by global sea level.

OneGeology-Europe: architecture, portal and web services to provide a European geological map

Science.gov (United States)

Tellez-Arenas, Agnès.; Serrano, Jean-Jacques; Tertre, François; Laxton, John

2010-05-01

OneGeology-Europe is a large ambitious project to make geological spatial data further known and accessible. The OneGeology-Europe project develops an integrated system of data to create and make accessible for the first time through the internet the geological map of the whole of Europe. The architecture implemented by the project is web services oriented, based on the OGC standards: the geological map is not a centralized database but is composed by several web services, each of them hosted by a European country involved in the project. Since geological data are elaborated differently from country to country, they are difficult to share. OneGeology-Europe, while providing more detailed and complete information, will foster even beyond the geological community an easier exchange of data within Europe and globally. This implies an important work regarding the harmonization of the data, both model and the content. OneGeology-Europe is characterised by the high technological capacity of the EU Member States, and has the final goal to achieve the harmonisation of European geological survey data according to common standards. As a direct consequence Europe will make a further step in terms of innovation and information dissemination, continuing to play a world leading role in the development of geosciences information. The scope of the common harmonized data model was defined primarily by the requirements of the geological map of Europe, but in addition users were consulted and the requirements of both INSPIRE and ‘high-resolution' geological maps were considered. The data model is based on GeoSciML, developed since 2006 by a group of Geological Surveys. The data providers involved in the project implemented a new component that allows the web services to deliver the geological map expressed into GeoSciML. In order to capture the information describing the geological units of the map of Europe the scope of the data model needs to include lithology; age; genesis and

Sedimentary mode and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin

Directory of Open Access Journals (Sweden)

Jinhu Du

2016-11-01

Full Text Available The gas reservoir of the Lower Cambrian Longwangmiao Fm in the Sichuan Basin is a supergiant integral marine carbonate gas reservoir whose single scale is currently the largest in China. In order to figure out its sedimentary model and reservoir genesis, its geological structures and sedimentary settings and facies were analyzed comprehensively and the lithofacies paleographic map was plotted. It is revealed that the following sedimentary facies are successively developed in the Longwangmiao Fm from West Sichuan to Southeast Chongqing: diamictic tidal flat at the back ramp, grain bank (the upper bank at the inner/shallow ramp – interbank sea (depression, deeper open bay at the platform depression of inner ramp → evaporative lagoon → evaporative tidal flat, tempestite at the middle ramp – barrier beach – mud mound beach (the lower bank, and outer ramp – basin. Accordingly, the specific sedimentary model of dual grain banks in the Longwangmiao Fm carbonate ramp was established as follows. Firstly, in this model, dual grain banks are symmetrically developed with Wanzhou–Yibin platform depression as the axis, on whose dual sides the paleohighs have shallow water bodies with strong energy. Compared with the classical model, the new one has a new upper bank which is developed around the paleohighs covering an area of about 8 × 104 km2. Secondly, the upper bank is large for its paleogeomorphology being located at the highest position with the strongest water energy during deposition. Therefore, it is prone to dolomitization and meteoric dissolution respectively during contemporaneous–penecontemporaneous hot-dry and hot-humid periods, and especially the Caledonian–Early Hercynian denudation wedge out tends to undergo post-supergene multiphase karstification. Therefore, quality reservoirs are more developed on scale. Thirdly, the intergranular pores and vermes moldic pores were dissolved and enlarged due to the multiphase

Epigenetic alterations of sedimentary rocks at deposits

International Nuclear Information System (INIS)

Komarova, G.V.; Kondrat'eva, I.A.; Zelenova, O.I.

1980-01-01

Notions are explained, and technique for studying epigenetic alterations of sedimentary rocks at uranium deposits is described. Main types of epigenetic transformations and their mineralogic-geochemical characteristics are considered. Rock alterations, accompanying uranium mineralization, can be related to 2 types: oxidation and reduction. The main mineralogic-geochemical property of oxidation transformations is epigenetic limonitization. Stratal limonitization in primary grey-coloured terrigenic rocks and in epigenetically reduced (pyritized) rocks, as well as in rock, subjected to epigenetic gleying, are characterized. Reduction type of epigenetic transformations is subdivided into sulphidic and non-sulphidic (gley) subtypes. Sulphidic transformations in grey-coloured terrigenic rocks with organic substance of carbonic row, in rocks, containing organic substance of oil row, sulphide transformations of sedimentary rocks, as well as gley transformations, are considered

Thermal conductivity of sedimentary rocks as function of Biot’s coefficient

DEFF Research Database (Denmark)

Orlander, Tobias; Pasquinelli, Lisa; Asmussen, J.J.

2017-01-01

A theoretical model for prediction of effective thermal conductivity with application to sedimentary rocks is presented. Effective thermal conductivity of sedimentary rocks can be estimated from empirical relations or theoretically modelled. Empirical relations are limited to the empirical...... conductivity of solids is typically orders of magnitude larger than that of fluids, grain contacts constituting the solid connectivity governs the heat transfer of sedi-mentary rocks and hence should be the basis for modelling effective thermal con-ductivity. By introducing Biot’s coefficient, α, we propose (1...... – α) as a measure of the solid connectivity and show how effective thermal conductivity of water saturated and dry sandstones can be modelled....

The role microbial sulfate reduction in the direct mediation of sedimentary authigenic carbonate precipitation

Science.gov (United States)

Turchyn, A. V.; Walker, K.; Sun, X.

2016-12-01

The majority of modern deep marine sediments are bathed in water that is undersaturated with respect to calcium carbonate. However, within marine sediments changing chemical conditions, driven largely by the microbial oxidation of organic carbon in the absence of oxygen, lead to supersaturated conditions and drive calcium carbonate precipitation. This sedimentary calcium carbonate is often called `authigenic carbonate', and is found in the form of cements and disseminated crystals within the marine sedimentary pile. As this precipitation of this calcium carbonate is microbially mediated, identifying authigenic carbonate within the geological record and understanding what information its geochemical and/or isotopic signature may hold is key for understanding its importance and what information it may contain past life. However, the modern controls on authigenic carbonate precipitation remain enigmatic because the myriad of microbially mediated reactions occurring within sediments both directly and indirectly impact the proton balance. In this submission we present data from 25 ocean sediment cores spanning the globe where we explore the deviation from the stoichiometrically predicted relationships among alkalinity, calcium and sulfate concentrations. In theory for every mol of organic carbon reduced by sulfate, two mol of alkalinity is produced, and to precipitate subsurface calcium carbonate one mol of calcium is used to consume two mol of alkalinity. We use this data with a model to explore changes in carbonate saturation state with depth below the seafloor. Alkalinity changes in the subsurface are poorly correlated with changes in calcium concentrations, however calcium concentrations are directly and tightly coupled to changes in sulfate concentrations in all studied sites. This suggests a direct role for sulfate reducing bacteria in the precipitation of subsurface carbonate cements.

Provenance of zircon of the lowermost sedimentary cover, Estonia, East-European Craton

Directory of Open Access Journals (Sweden)

Konsa, M.

1999-12-01

Full Text Available Bulk and accessory mineral composition of fresh and weathered crystalline rocks, and sedimentary deposits overlying the crystalline-sedimentary unconformity have been examined in core samples from 28 drill holes in Estonia. Before the Late Vendian to Early Cambrian regional subsidence and sedimentation, the region represented a flat plateau within the Svecofennian Domain. Palaeo-and Mesoproterozoic crystalline rocks, regardless their different initial mineral composition, subcrop under the Upper Vendian/Lower Cambrian sedimentary cover as usually intensely weathered rocks (saprolites composed of residual quartz, altered micas and prevailing clay minerals mainly of the kaolinite group. Thus, the bulk mineral composition of any basement crystalline rocks imparts no specific inherited rock-forming minerals into the covering sedimentary rocks. From the variety of accessory and opaque minerals of crystalline rocks, only zircon populations survived in saprolites. Crystalline rocks of different origin yield different zircons. Relationships between the zircon typology of the basement rocks having specific areas of distribution and the sedimentary rocks immediately overlying those crystalline rocks were the main subject of this study. The result is that siliciclastic sedimentary rocks covering weathered crystalline rocks only in places inherited zircons with typological features characteristic of specific basement areas. In northeastern Estonia, local lenses of the Oru Member (the earliest Upper Vendian sedimentary rocks in Estonia resembling the debris of weathered crystalline rocks yield accessory zircon which in a 1-2 m thick layer above the basement surface is similar to the zircons of the underlying weathering mantle of certain crystalline rocks. In the next unit, the Moldova Member, up to 43 m above the basement surface, a mixture of zircons resembling those of various local basement rocks has been found. Further upwards, in the Vendian and Lower

Geologic History of Eocene Stonerose Fossil Beds, Republic, Washington, USA

Directory of Open Access Journals (Sweden)

George E. Mustoe

2015-07-01

Full Text Available Eocene lakebed sediments at Stonerose Interpretive Center in Republic, Washington, USA are one of the most important Cenozoic fossil sites in North America, having gained international attention because of the abundance and diversity of plant, insect, and fish fossils. This report describes the first detailed geologic investigation of this unusual lagerstätten. Strata are gradationally divided into three units: Siliceous shale that originated as diatomite, overlain by laminated mudstone, which is in turn overlain by massive beds of lithic sandstone. The sedimentary sequence records topographic and hydrologic changes that caused a deep lake to become progressively filled with volcaniclastic detritus from earlier volcanic episodes. The location of the ancient lake within an active graben suggests that displacements along the boundary faults were the most likely trigger for changes in depositional processes.

Geology and Nonfuel Mineral Deposits of Africa and the Middle East

Science.gov (United States)

Taylor, Cliff D.; Schulz, Klaus J.; Doebrich, Jeff L.; Orris, Greta; Denning, Paul; Kirschbaum, Michael J.

2009-01-01

A nation's endowment of nonfuel mineral resources, relative to the world's endowment, is a fundamental consideration in decisions related to a nation's economic and environmental well being and security. Knowledge of the worldwide abundance, distribution, and general geologic setting of mineral commodities provides a framework within which a nation can make decisions about economic development of its own resources, and the economic and environmental consequences of those decisions, in a global perspective. The information in this report is part of a U.S. Geological Survey (USGS) endeavor to evaluate the global endowment of both identified and undiscovered nonfuel mineral resources. The results will delineate areas of the world that are geologically permissive for the occurrence of undiscovered selected nonfuel mineral resources together with estimates of the quantity and quality of the resources. The results will be published as a series of regional reports; this one provides basic data on the identified resources and geologic setting, together with a brief appraisal of the potential for undiscovered mineral resources in Africa and the Middle East. Additional information, such as production statistics, economic factors that affect the mineral industries of the region, and historical information, is available in U.S. Geological Survey publications such as the Minerals Yearbook and the annual Mineral Commodity Summaries (available at http://minerals.usgs.gov/minerals).

Geology and geothermics of the Island of Milos (Greece)

Energy Technology Data Exchange (ETDEWEB)

Fytikas, M.; Marinelli, G.

1976-01-01

Geothermal research which has been conducted on the island of Milos is reviewed and the island's geology is discussed in terms of the geodynamics of the eastern Mediterranean. The rock formations which outcrop at Milos are described in detail, including the crystalline basement, Neogene transgressive conglomerates and limestones, and the Quaternary volcanics and volcano-sedimentary series. The recent disjunctive tectonics and volcano-tectonics affecting Milos and the neighboring islands are reviewed. Thermal manifestations and their attendant mineralizations and hydrothermal alterations are described. The geophysical methods utilized in exploration and for the siting of production wells are described. Exploration work involved the drilling of 55 wells for thermometric determinations and a full scale electrical survey. Preliminary data from two production wells with bottom-hole temperatures in excess of 300/sup 0/C are reported. Fifty-four references are provided.

The UNESCO Global Network of National Geoparks

Science.gov (United States)

Mc Keever1, P.; Zouros, N.; Patzak, M.; Missotten, R.

2009-12-01

The UNESCO Global Network of National Geoparks was founded in 2004, following the model successfully established by the European Geoparks Network in 2000. It now comprises 63 members in 19 nations across the world. A Global Geopark is an area with geological heritage of international value but where that heritage is being used for the sustainable economic benefit if the local inhabitants, primarily through education and tourism. Supported by IUGS and IUCN, the aim of the Global Geoparks Network is to facilitate exchange and sharing between members to assist in the protection and conservation of the geological heritage of our planet but to do so in way where local communities can take ownership of these special places and where they can get some sustainable economic benefit from them. While allowing for the sustainable economic development of geoparks, the network explicitly forbids the destruction or sale of the geological value of a geopark. This paper outlines the ethos of the Global Geoparks Network and describes the typical activities of geoparks and how the network functions. Using two examples it also illustrates how members of the Global Geoparks Network provide good examples as tools not only for holistic nature conservation but also for economic development.

How semantics can inform the geological mapping process and support intelligent queries

Science.gov (United States)

Lombardo, Vincenzo; Piana, Fabrizio; Mimmo, Dario

2017-04-01

how the formal encoding of the geological knowledge opens new perspectives for the analysis and representation of the geological systems. In fact, once that the major concepts are defined, the resulting formal conceptual model of the geologic system can hold across different technical and scientific communities. Furthermore, this would allow for a semi-automatic or automatic classification of the cartographic database, where a significant number of properties (attributes) of the recorded instances could be inferred through computational reasoning. So, for example, the system can be queried for showing the instances that satisfy some property (e.g., "Retrieve all the lithostratigraphic units composed of clastic sedimentary rock") or for classifying some unit according to the properties holding for that unit (e.g., "What is the class of the geologic unit composed of siltstone material?").

Geochemical characteristics of the Permian sedimentary rocks from Qiangtang Basin: Constraints for paleoenvironment and paleoclimate

Directory of Open Access Journals (Sweden)

Junjie Hu

2017-01-01

Full Text Available Qiangtang Basin is expected to become important strategic petroleum exploitation area in China. However, little research has been done on the Permian strata in this area. This paper presents Lower Permian Zhanjin Formation geochemical data from the Jiaomuri area, reconstructing the paleo-depositional environment and providing information for further petroleum exploration. The geochemical characteristics of 19 samples were investigated. These geochemical samples show a developed mud flat characteristic with light rich clay content. The geological data were used to constrain the paleoredox environment, which proved that these sediments were deposited mainly beneath a slightly oxic water column with relatively low paleoproductivity as evidenced by the P/Ti (mean of 0.07 and Ba/Al (mean of 20.5. Palaeoclimate indexes such as the C-value (0.24-1.75 and Sr/Cu (1.28-11.58 reveal a humid climatic condition during Zhanjin Formation sediment deposition. The ω(LaN/ω(YbN ratio values indicate a fast sedimentary rate during the deposition period.

Airborne radiometric data - A tool for reconnaissance geological mapping using a GIS

International Nuclear Information System (INIS)

Graham, D.F.; Bonham-Carter, G.F.

1993-01-01

A clustering technique is applied to radioelement data, and the resulting cluster map is compared with a digitized geological map within a GIS software package. The cross tabulation clearly identifies those geological units that have a distinctive radioelement response. By reclassifying the map overlay and imposing a color coding scheme that enhances bedrock geology classes, the relationship between the bedrock geology and radioelement response is enhanced. The degree of correlation between the two cartographic images is site dependent, rather than global. Areas where the two maps differ indicate zones of possible interest for field verification of published field maps for the purposes of mineral exploration. 13 refs

Engineering Geology | Alaska Division of Geological & Geophysical Surveys

Science.gov (United States)

Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska content Engineering Geology Additional information Engineering Geology Posters and Presentations Alaska Alaska MAPTEACH Tsunami Inundation Mapping Engineering Geology Staff Projects The Engineering Geology

Appraisal of the physical and dynamic state of the Mayak operations geological environment with a view to underground radwaste disposal

International Nuclear Information System (INIS)

Velichkin, V.I.; Petrov, V.A.; Tarasov, N.N.; Poluektov, V.V.; Kochkin, B.T.; Asadulin, A.A.; Volkov, A.B.

1995-01-01

The results of the research into geological structure, geomorphology, paleotectonics, mineralogy and petrography, petrophysics and petrochemistry of the site occupied by the Mayak radiochemical operations are presented. The research was aimed at the identification of the site for underground disposal of solidified high-level radioactive wastes (HLW). Geotectonic position of the district in the regional structures is shown, and paragenesis of fold and fault structures formed at the various stages and under various conditions of strains in the geological environment are described. The internal structure, nature and rates of the development of the processes of metamorphic and hydrothermal-metasomatic transformation of the geological environment, as well as basic petrogeochemical features of the strata were brought out. Stress-strained state of the strata at the stage of Cenozoic deformations that is retained nowadays was simulated. Basic petrophysical characteristics of adjoining strata were identified. Non-uniformity of the development of fissure-pore systems in the profile of strata of volcanic and sedimentary origin and peculiarities of deformations were revealed. The given comprehensive research was recommended for the identification of geological blocks suitable in varying degrees for the HLW disposal to the district

Transferability of geodata from European to Canadian (Ontario) sedimentary rocks to study gas transport from nuclear wastes repositories

International Nuclear Information System (INIS)

Fall, M.; Ghafari, H.; Evgin, E.; Nguyen, T.S.

2010-01-01

Document available in extended abstract form only. A deep geological repository (DGR) for low and intermediate level waste in southern Ontario is currently proposed, at a depth of approximately 680 m in an argillaceous limestone formation (Cobourg Limestone) overlain by 200 m of low permeability shale (Ordovician Shale). Significant quantities of gas could be generated in the aforementioned DGR from several processes (e.g., degradation of waste forms, corrosion of waste containers). The accumulation and release of such gases from the repository system may affect a number of processes that influence its long-term safety. Consequently, safety assessments of the proposed DGR need to be supported by a solid understanding of the main mechanisms associated with gas generation and migration and the capability to mathematically model those mechanisms. The development of those mathematical models would usually require the consideration of complex coupled thermo-hydro-mechanical- chemical (THMC) processes. A research program is being conducted in the Department of Civil Engineering of the University of Ottawa in collaboration with the Canadian Nuclear Safety Commission (CNSC) to model the coupled THMC processes associated with gas migration and their impacts on the safety of DGR in southern Ontario. The development and validation of such model as well as the assessment of the impact of gas migration need the acquisition of sufficient amount of (good quality) data on the geomechanical, geochemical, hydraulic, thermal properties of the sedimentary rocks in Southern Ontario as well as relevant gas transport parameters, such as gas entry pressure, Klinkenberg effect, intrinsic permeability, capillary pressure-water saturation relationship. During the past fifteen years, several laboratory and field investigations have been conducted in several countries to acquire geo-data to study and model the THMC processes associated with gas migration in DGR in sedimentary rocks. However

Bedrock geologic map of the northern Alaska Peninsula area, southwestern Alaska

Science.gov (United States)

Wilson, Frederic H.; Blodgett, Robert B.; Blome, Charles D.; Mohadjer, Solmaz; Preller, Cindi C.; Klimasauskas, Edward P.; Gamble, Bruce M.; Coonrad, Warren L.

2017-03-03

The northern Alaska Peninsula is a region of transition from the classic magmatic arc geology of the Alaska Peninsula to a Proterozoic and early Paleozoic carbonate platform and then to the poorly understood, tectonically complex sedimentary basins of southwestern Alaska. Physiographically, the region ranges from the high glaciated mountains of the Alaska-Aleutian Range to the coastal lowlands of Cook Inlet on the east and Bristol Bay on the southwest. The lower Ahklun Mountains and finger lakes on the west side of the map area show strong effects from glaciation. Structurally, a number of major faults cut the map area. Most important of these are the Bruin Bay Fault that parallels the coast of Cook Inlet, the Lake Clark Fault that cuts diagonally northeast to southwest across the eastern part of the map area, and the presently active Holitna Fault to the northwest that cuts surficial deposits.Distinctive rock packages assigned to three provinces are overlain by younger sedimentary rocks and intruded by widely dispersed latest Cretaceous and (or) early Tertiary granitic rocks. Much of the east half of the map area lies in the Alaska-Aleutian Range province; the Jurassic to Tertiary Alaska-Aleutian Range batholith and derivative Jurassic sedimentary rocks form the core of this province, which is intruded and overlain by the Aleutian magmatic arc. The Lime Hills province, the carbonate platform, occurs in the north-central part of the map area. The Paleozoic and Mesozoic Ahklun Mountains province in the western part of the map area includes abundant chert, argillite, and graywacke and lesser limestone, basalt, and tectonic mélange. The Kuskokwim Group, an Upper Cretaceous turbidite sequence, is extensively exposed and bounds all three provinces in the west-central part of the map area.

Uranium prospecting and geological favour ability in Uruguay; Prospeccion uranifera y favorabilidad geologica en el Uruguay

Energy Technology Data Exchange (ETDEWEB)

Goso, H [Comision Nacional de Energia Atomica, Montevideo (Uruguay)

1981-07-01

Uranium prospecting carried out in Uruguay since 1976 is described. On the basis of literature available and of an analysis of the large structural units pertinent to Uruguay's geology, the prospecting performed in general in the northeast of the country, and in particular in the districts of Cerro Largo and Las Canas, is described. Some information is presented on uranium favour ability in Uruguay related to sedimentary formations: Devonian (Cerrezuelo Formation) and Gondwana (San Gregorio and Tres Islas Formations), and to the Crystalline formations of the centre and Southwest (1700-2000 m.y.) and of the east and southeast (500-700 m.y.)

Lower Tertiary Sedimentary Turbidite Facies at the Chicontepec Basin, East-Central Mexico

Directory of Open Access Journals (Sweden)

Santillán-Piña N.

2011-07-01

Full Text Available The study area comprises the northwestern portion of the Chicontepec Basin at southeastern San Luis Potosí and northeastern Hidalgo States. At the stratigraphy sequences of the Chicontepec Formation from Lower Paleocene in isolated outocrops, were herein interpreted two major sedimentary sub-environments into the fan model: the middle and the external sedimentary settings; the applied criteria for their identification were: (a lithostratigraphic (thickness, geometry and distribution; (b internal and external primary sedimentary structures, and (c intra-formational deformation structures. The sedimentary facies are composed of siliciclastic and calcareous particles sourced from the Sierra Madre Oriental, western; the Tuxpan paleo-island, eastern; and from the Teziutlan Massif, southern; the sediments were massively transported by slideing, slumping, flow debris and turbidity currents, then deposited as massive, tabular, lenticular and lobely in shape at the slope foot and on the sea marine floor.

Potentiality if Rb-Sr method for dating the argillous sedimentary rocks

International Nuclear Information System (INIS)

Thomaz Filho, A.

1976-01-01

The potentiality of application Rb-Sr method in argillous sediments, using samples from paleozoic and mesozoic formation in brazilian sedimentaries basin was tested. Physical, chemistry and isotopic analysis of thirty eight samples were made in the laboratories of geochronology Research Center from the University of Sao Paulo. Four isochronic diagrams for the argillous sedimentary rocks were also proposed. (author)

Quantifying time in sedimentary successions by radio-isotopic dating of ash beds

Science.gov (United States)

Schaltegger, Urs

2014-05-01

Sedimentary rock sequences are an accurate record of geological, chemical and biological processes throughout the history of our planet. If we want to know more about the duration or the rates of some of these processes, we can apply methods of absolute age determination, i.e. of radio-isotopic dating. Data of highest precision and accuracy, and therefore of highest degree of confidence, are obtained by chemical abrasion, isotope-dilution, thermal ionization mass spectrometry (CA-ID-TIMS) 238U-206Pb dating techniques, applied to magmatic zircon from ash beds that are interbedded with the sediments. This techniques allows high-precision estimates of age at the 0.1% uncertainty for single analyses, and down to 0.03% uncertainty for groups of statistically equivalent 206Pb/238U dates. Such high precision is needed, since we would like the precision to be approximately equivalent or better than the (interpolated) duration of ammonoid zones in the Mesozoic (e.g., Ovtcharova et al. 2006), or to match short feedback rates of biological, climatic, or geochemical cycles after giant volcanic eruptions in large igneous provinces (LIP's), e.g., at the Permian/Triassic or the Triassic/Jurassic boundaries. We also wish to establish as precisely as possible temporal coincidence between the sedimentary record and short-lived volcanic events within the LIP's. Precision and accuracy of the U-Pb data has to be traceable and quantifiable in absolute terms, achieved by direct reference to the international kilogram, via an absolute calibration of the standard and isotopic tracer solutions. Only with a perfect control on precision and accuracy of radio-isotopic data, we can confidently determine whether two ages of geological events are really different, and avoid mistaking interlaboratory or interchronometer biases for age difference. The development of unprecedented precision of CA-ID-TIMS 238U-206Pb dates led to the recognition of protracted growth of zircon in a magmatic liquid (see

Canada's deep geological repository for used nuclear fuel - update on the site evaluation process and interweaving of aboriginal traditional knowledge

Energy Technology Data Exchange (ETDEWEB)

Watts, B.; Belfadhel, M.B.; Facella, J., E-mail: bwatt@nwmo.ca, E-mail: mbenbelfadhel@nwmo.ca, E-mail: jfacella@nwmo.ca [Nuclear Waste Management Organization, Toronto, ON (Canada)

2015-07-01

The Nuclear Waste Management Organization (NWMO) is responsible for implementing Adaptive Phased Management (APM), the approach selected by the Government of Canada for the long-term management of used nuclear fuel generated by Canadian nuclear reactors. The ultimate objective of APM is the centralized containment and isolation of Canada's used nuclear fuel in a Deep Geological Repository (DGR) in a suitable crystalline or sedimentary rock formation. In May 2010, the NWMO initiated a nine-step site selection process to seek an informed and willing community to host Canada's deep geological repository. As of April 2015, twenty-two communities expressed interest in learning more about the project. This paper provides an update on the site evaluation process and describes the approach, methods and criteria used in the assessments, focusing on geological and community well-being studies. Engagement and field activities to interweave Aboriginal Traditional Knowledge with western science are also discussed. (author)

CONTRIBUTION OF SATELLITE ALTIMETRY DATA IN GEOLOGICAL STRUCTURE RESEARCH IN THE SOUTH CHINA SEA

Directory of Open Access Journals (Sweden)

T. D. Tran

2016-06-01

Full Text Available The study area is bordered on the East China Sea, the Philippine Sea, and the Australian-Indo plate in the Northeast, in the East and in the South, respectively. It is a large area with the diversely complicated conditions of geological structure. In spite of over the past many years of investigation, marine geological structure in many places have remained poorly understood because of a thick seawater layer as well as of the sensitive conflicts among the countries in the region. In recent years, the satellite altimeter technology allows of enhancement the marine investigation in any area. The ocean surface height is measured by a very accurate radar altimeter mounted on a satellite. Then, that surface can be converted into marine gravity anomaly or bathymetry by using the mathematical model. It is the only way to achieve the data with a uniform resolution in acceptable time and cost. The satellite altimetry data and its variants are essential for understanding marine geological structure. They provide a reliable opportunity to geologists and geophysicists for studying the geological features beneath the ocean floor. Also satellite altimeter data is perfect for planning the more detailed shipboard surveys. Especially, it is more meaningful in the remote or sparsely surveyed regions. In this paper, the authors have effectively used the satellite altimetry and shipboard data in combination. Many geological features, such as seafloor spreading ridges, fault systems, volcanic chains as well as distribution of sedimentary basins are revealed through the 2D, 3D model methods of interpretation of satellite-shipboard-derived data and the others. These results are improved by existing boreholes and seismic data in the study area.

Modern sedimentary environments in a large tidal estuary, Delaware Bay

Science.gov (United States)

Knebel, H.J.

1989-01-01

Data from an extensive grid of sidescan-sonar records reveal the distribution of sedimentary environments in the large, tidally dominated Delaware Bay estuary. Bathymetric features of the estuary include large tidal channels under the relatively deep (> 10 m water depth) central part of the bay, linear sand shoals (2-8 m relief) that parallel the sides of the tidal channels, and broad, low-relief plains that form the shallow bay margins. The two sedimentary environments that were identified are characterized by either (1) bedload transport and/or erosion or (2) sediment reworking and/or deposition. Sand waves and sand ribbons, composed of medium to coarse sands, define sites of active bedload transport within the tidal channels and in gaps between the linear shoals. The sand waves have spacings that vary from 1 to 70 m, amplitudes of 2 m or less, and crestlines that are usually straight. The orientations of the sand waves and ribbons indicate that bottom sediment movement may be toward either the northwest or southeast along the trends of the tidal channels, although sand-wave asymmetry indicates that the net bottom transport is directed northwestward toward the head of the bay. Gravelly, coarse-grained sediments, which appear as strongly reflective patterns on the sonographs, are also present along the axes and flanks of the tidal channels. These coarse sediments are lag deposits that have developed primarily where older strata were eroded at the bay floor. Conversely, fine sands that compose the linear shoals and muddy sands that cover the shallow bay margins appear mainly on the sonographs either as smooth featureless beds that have uniform light to moderate shading or as mosaics of light and dark patches produced by variations in grain size. These acoustic and textural characteristics are the result of sediment deposition and reworking. Data from this study (1) support the hypothesis that bed configurations under deep tidal flows are functions of current

A state geological survey commitment to environmental geology - the Texas Bureau of Economic Geology

International Nuclear Information System (INIS)

Wermund, E.G.

1990-01-01

In several Texas environmental laws, the Bureau of Economic Geology is designated as a planning participant and review agency in the process of fulfilling environmental laws. Two examples are legislation on reclamation of surface mines and regulation of processing low level radioactive wastes. Also, the Bureau is the principal geological reviewer of all Environmental Assessments and Environmental Impact Statements which the Office of the Governor circulates for state review on all major developmental activities in Texas. The BEG continues its strong interest in environmental geology. In February 1988, it recommitted its Land Resources Laboratory, initiated in 1974, toward fulfilling needs of state, county, and city governments for consultation and research on environmental geologic problems. An editorial from another state geological survey would resemble the about description of texas work in environmental geology. State geological surveys have led federal agencies into many developments of environmental geology, complemented federal efforts in their evolution, and continued a strong commitment to the maintenance of a quality environment through innovative geologic studies

Geologic characterization of Cuvette Centrale petroleum systems Congo-DRC

Energy Technology Data Exchange (ETDEWEB)

Vicentelli, Maria Gabriela C.; Barbosa, Mauro; Rezende, Nelio G.A.M. [HRT Petroleum, Rio de Janeiro, RJ (Brazil)

2008-07-01

The Cuvette Centrale is an almost unexplored basin, which contains some petroleum system elements that indicate the presence of hydrocarbons. In this sense; this paper presents an exploratory alternative for this intracratonic basin. The interpretation of the limited gravimetric, magnetometric, geochemical and seismic available data allowed the identification of many huge structural features and also some areas with hydrocarbon potential for stratigraphic traps. The presence of several oil and gas seeps widespread around the Busira and Lokoro sub-basins indicate that at least one active petroleum system exist in the basin. Despite only four wells have been drilled in the basin, one of them presented oil shows during drilling. Geological correlations between Brazilian Paleozoic basins and Cuvette Centrale sedimentary sequences permitted to conclude that Cambro-Ordovician and Siluro-Devonian source rocks must be present and active in the Cuvette Centrale basin. The tectono-stratigraphic evolution history of the Cuvette Centrale from Neo proterozoic to Recent times shows extensional and compressional/transpressional alternating phases along the geological time. The most confident petroleum system expected in the Cuvette Centrale is characterized by the Cambrian Mamungi shale - source rock - and the Cambro-Ordovician. Upper Arenaceous Sequence - reservoirs, as observed in the MBandaka and Gilson wells and confirmed by surface geology in outcrops. Besides, other potential petroleum systems are expected to occur in the basin. One is characterized by the Neo proterozoic Itury Group source rock and reservoirs in the mature/over mature stage, the others are the Siluro-Devonian and Cretaceous source rocks and reservoirs, expected to occur with better maturity conditions only in the deeper parts of the basin. (author)

Major episodes of geologic change - Correlations, time structure and possible causes

Science.gov (United States)

Rampino, Michael R.; Caldeira, Ken

1993-01-01

Published data sets of major geologic events of the past about 250 Myr (extinction events, sea-level lows, continental flood-basalt eruptions, mountain-building events, abrupt changes in sea-floor spreading, ocean-anoxic and blackshale events and the largest evaporite deposits) have been synthesized (with estimated errors). These events show evidence for a statistically significant periodic component with an underlying periodicity, formally equal to 26.6 Myr, and a recent maximum, close to the present time. The cycle may not be strictly periodic, but a periodicity of about 30 Myr is robust to probable errors in dating of the geologic events. The intervals of geologic change seem to involve jumps in sea-floor spreading associated with episodic continental rifting, volcanism, enhanced orogeny, global sea-level changes and fluctuations in climate. The period may represent a purely internal earth-pulsation, but evidence of planetesimal impacts at several extinction boundaries, and a possible underlying cycle of 28-36 Myr in crater ages, suggests that highly energetic impacts may be affecting global tectonics. A cyclic increase in the flux of planetesimals might result from the passage of the Solar System through the central plane of the Milky Way Galaxy - an event with a periodicity and mean phasing similar to that detected in the geologic changes.

Alteration of Sedimentary Clasts in Martian Meteorite Northwest Africa 7034

Science.gov (United States)

McCubbin, F. M.; Tartese, R.; Santos, A. R.; Domokos, G.; Muttik, N.; Szabo, T.; Vazquez, J.; Boyce, J. W.; Keller, L. P.; Jerolmack, D. J.;

Correlation of uranium geology between South America and Africa

International Nuclear Information System (INIS)

1986-01-01

Acting upon the recommendation of an Advisory Group Meeting held in 1980, the IAEA organized a Working Group on the Correlation of the Uranium Geology between South America and Africa because of the tremendous geological potential for uranium and the interest showed by the Member States of the regions concerned. The report of this Working Group is now presented. The aim of this report is to provide the nuclear industry and, in particular, the countries of the region with a broad but updated outline of current development in the uranium geology and the uranium potential of Africa and South America. The scope is such that it will provide, for those not directly involved in uranium exploration in the area, a general technical summary on the regional geology and tectonics of these two continents in order that the geodynamic setting of their uranium occurrences may be correlated. With respect to the area to be covered and bearing in mind the purpose of this study, the Working Group surveyed the most relevant parts of western Gondwanaland, of which the two continents form a part. The area covered by the report extends from north of the West African Craton and the Guiana Shield to the southern end of South America and Africa; from the Amazonian Province in western Brazil and western Argentina to the central part of the West African Craton, Congo-Kasai Craton. The Andean Chain in South America and the Atlas Mountains in North Africa, which were formed by continental accretion in recent geological time and post-dated the split and drift of the two land masses, were not considered. Some of the inner portions of those cratons distant from the coastlines and for which the correlation features do not apply have also been omitted. However, certain areas of important uranium mineralization outside the main study area have been described in order to offer comparative models for future exploration elsewhere. The subject of the report is discussed under six headings: cratonic areas

Preliminary subsurface hydrologic considerations: Columbia River Plateau Physiographic Province. Assessment of effectiveness of geologic isolation systems

International Nuclear Information System (INIS)

Veatch, M.D.

1980-04-01

This report contains a discussion of the hydrologic conditions of the Columbia River Plateau physiographic province. The Columbia River Plateau is underlain by a thick basalt sequence. The Columbia River basalt sequence contains both basalt flows and sedimentary interbeds. These sedimentary interbeds, which are layers of sedimentary rock between lava flows, are the main aquifer zones in the basalt sequence. Permeable interflow zones, involving the permeable top and/or rubble bottom of a flow, are also water-transmitting zones. A number of stratigraphic units are present in the Pasco Basin, which is in the central part of the Columbia River Plateau. At a conceptual level, the stratigraphic sequence from the surface downward can be separated into four hydrostratigraphic systems. These are: (1) the unsaturated zone, (2) the unconfined aquifer, (3) the uppermost confined aquifers, and (4) the lower Yakima basalt hydrologic sequence. A conceptual layered earth model (LEM) has been developed. The LEM represents the major types of porous media (LEM units) that may be encountered at a number of places on the Columbia Plateau, and specifically in the Pasco Basin. The conceptual LEM is not representative of the actual three-dimensional hydrostratigraphic sequence and hydrologic conditions existing at any specific site within the Columbia Plateau physiographic province. However, the LEM may be useful for gaining a better understanding of how the hydrologic regime may change as a result of disruptive events that may interact with a waste repository in geologic media

Summary of 2012 reconnaissance field studies related to the petroleum geology of the Nenana Basin, interior Alaska

Science.gov (United States)

Wartes, Marwan A.; Gillis, Robert J.; Herriott, Trystan M.; Stanley, Richard G.; Helmold, Kenneth P.; Peterson, C. Shaun; Benowitz, Jeffrey A.

2013-01-01

The Alaska Division of Geological & Geophysical Surveys (DGGS) recently initiated a multi-year review of the hydrocarbon potential of frontier sedimentary basins in Alaska (Swenson and others, 2012). In collaboration with the Alaska Division of Oil & Gas and the U.S. Geological Survey we conducted reconnaissance field studies in two basins with recognized natural gas potential—the Susitna basin and the Nenana basin (LePain and others, 2012). This paper summarizes our initial work on the Nenana basin; a brief summary of our work in the Susitna basin can be found in Gillis and others (in press). During early May 2012, we conducted ten days of helicopter-supported fieldwork and reconnaissance sampling along the northern Alaska Range foothills and Yukon–Tanana upland near Fairbanks (fig. 1). The goal of this work was to improve our understanding of the geologic development of the Nenana basin and to collect a suite of samples to better evaluate hydrocarbon potential. Most laboratory analyses have not yet been completed, so this preliminary report serves as a summary of field data and sets the framework for future, more comprehensive analysis to be presented in later publications.

Modelling hydrothermal venting in volcanic sedimentary basins: Impact on hydrocarbon maturation and paleoclimate

Science.gov (United States)

Iyer, Karthik; Schmid, Daniel W.; Planke, Sverre; Millett, John

2017-06-01

Vent structures are intimately associated with sill intrusions in sedimentary basins globally and are thought to have been formed contemporaneously due to overpressure generated by gas generation during thermogenic breakdown of kerogen or boiling of water. Methane and other gases generated during this process may have driven catastrophic climate change in the geological past. In this study, we present a 2D FEM/FVM model that accounts for 'explosive' vent formation by fracturing of the host rock based on a case study in the Harstad Basin, offshore Norway. Overpressure generated by gas release during kerogen breakdown in the sill thermal aureole causes fracture formation. Fluid focusing and overpressure migration towards the sill tips results in vent formation after only few tens of years. The size of the vent depends on the region of overpressure accessed by the sill tip. Overpressure migration occurs in self-propagating waves before dissipating at the surface. The amount of methane generated in the system depends on TOC content and also on the type of kerogen present in the host rock. Generated methane moves with the fluids and vents at the surface through a single, large vent structure at the main sill tip matching first-order observations. Violent degassing takes place within the first couple of hundred years and occurs in bursts corresponding to the timing of overpressure waves. The amount of methane vented through a single vent is only a fraction (between 5 and 16%) of the methane generated at depth. Upscaling to the Vøring and Møre Basins, which are a part of the North Atlantic Igneous Province, and using realistic host rock carbon content and kerogen values results in a smaller amount of methane vented than previously estimated for the PETM. Our study, therefore, suggests that the negative carbon isotope excursion (CIE) observed in the fossil record could not have been caused by intrusions within the Vøring and Møre Basins alone and that a contribution

Geology and ground water in north-central Santa Cruz County, California

Science.gov (United States)

Johnson, Michael J.

1980-01-01

North-central Santa Cruz County is underlain mainly by folded sedimentary rocks of Tertiary and Cretaceous age that have been highly fractured by movements in the San Andreas fault system. Ground water is stored in fractures within shale and mudstone formations and in intergranular pore spaces within fine- to very fine-grained sandstone and siltstone formations. Fewer than 10% of the wells yield more than 15 gallons of water per minute. The water in most wells is moderately hard to very hard, is generally of a sodium bicarbonate or calcium bicarbonate type, and commonly has excessive concentrations of iron or manganese. Of the many geologic units in the study area, only the Purisima Formation of Pliocene age has the potential to sustain well yields greater than 100 gallons per minute. (USGS)

The Geologic Signature of Anaerobic Oxidation of Methane (Invited)

Science.gov (United States)

Ussler, W.; Paull, C. K.

2010-12-01

Anaerobic oxidation of methane (AOM) is an enormous sink in anoxic marine sediments for methane produced in situ or ascending through the sediment column towards the seafloor. Existing estimates indicate that between 75 and 382 Tg of sedimentary methane are oxidized each year before reaching the sediment-water interface making AOM a diagenetic process of global significance. This methane is derived from a variety of sources including microbial production, thermocatalytic cracking of complex organic matter, decomposing gas hydrates, and possibly abiogenic processes. Stables isotopes of membrane lipid biomarkers and authigenic carbonates associated with zones of AOM, fluorescence in situ hybridization, and anaerobic methane incubations have substantiated the role Archaea and sulfate-reducing bacteria have in driving AOM. The products of AOM are dissolved inorganic carbon (predominantly HCO3-) and bisulfide (HS-). Stable isotope measurements of authigenic carbonates associated with zones of AOM are consistent with the diagenetic carbon being primarily methane derived. These methane-derived carbonates occur in a variety of forms including sedimentary nodules and thin lenses within and below zones of contemporary AOM; outcrops of slabs, ledges, and jagged authigenic carbonates exhumed on the seafloor; and authigenic carbonate mounds associated with near-subsurface methane gas accumulations. Examples of exhumed authigenic carbonates include rugged outcrops along the Guaymas Transform in the Gulf of California, extensive slabs and ledges in the Eel River Basin, and mounds in various stages of development near Bullseye Vent, off Vancouver Island and in the Santa Monica Basin. It is clear from basic microbial biogeochemistry and the occurrences of massive authigenic carbonate which span a large range in size that DIC produced by AOM is preserved as authigenic carbonate within the seafloor and not on the seafloor. These exhumed authigenic carbonate provide a glimpse of how

The Mizunami underground research laboratory in Japan - programme for study of the deep geological environment

International Nuclear Information System (INIS)

Sakuma, Hideki; Sugihara, Kozo; Koide, Kaoru; Mikake, Shinichiro

1998-01-01

This paper is an overview of the PNC's Mizunami Underground Research Laboratory project in Mizunami City, central Japan. The Mizunami Underground Research Laboratory now will succeed the Kamaishi Mine as the main facility for the geoscientific study of the crystalline environment. The site will never be considered as a site for a repository. The surface-based investigations, planned to continue for some 5 years commenced in the autumn 1997. The construction of the facility to the depth of 1000 m is currently planned to: Develop comprehensive investigation techniques for geological environment; Acquire data on the deep geological environment and to; Develop a range of engineering techniques for deep underground application. Besides PNC research, the facility will also be used to promote deeper understanding of earthquakes, to perform experiments under micro-gravity conditions etc. The geology of the site is shortly as follows: The sedimentary overburden some 20 - 100 m in thickness is of age 2 - 20 million years. The basement granite is approx. 70 million years. A reverse fault is crosscutting the site. The identified fault offers interesting possibilities for important research. Part of the work during the surface-based investigations, is to drill and test deep boreholes to a planned depth up to 2000 m. Based on the investigations, predictions will be made what geological environment will be encountered during the Construction Phase. Also the effect of construction will be predicted. Methodology for evaluation of predictions will be established

Geologic Mapping Results for Ceres from NASA's Dawn Mission

Science.gov (United States)

Williams, D. A.; Mest, S. C.; Buczkowski, D.; Scully, J. E. C.; Raymond, C. A.; Russell, C. T.

2017-12-01

NASA's Dawn Mission included a geologic mapping campaign during its nominal mission at dwarf planet Ceres, including production of a global geologic map and a series of 15 quadrangle maps to determine the variety of process-related geologic materials and the geologic history of Ceres. Our mapping demonstrates that all major planetary geologic processes (impact cratering, volcanism, tectonism, and gradation (weathering-erosion-deposition)) have occurred on Ceres. Ceres crust, composed of altered and NH3-bearing silicates, carbonates, salts and 30-40% water ice, preserves impact craters and all sizes and degradation states, and may represent the remains of the bottom of an ancient ocean. Volcanism is manifested by cryovolcanic domes, such as Ahuna Mons and Cerealia Facula, and by explosive cryovolcanic plume deposits such as the Vinalia Faculae. Tectonism is represented by several catenae extending from Ceres impact basins Urvara and Yalode, terracing in many larger craters, and many localized fractures around smaller craters. Gradation is manifested in a variety of flow-like features caused by mass wasting (landslides), ground ice flows, as well as impact ejecta lobes and melts. We have constructed a chronostratigraphy and geologic timescale for Ceres that is centered around major impact events. Ceres geologic periods include Pre-Kerwanan, Kerwanan, Yalodean/Urvaran, and Azaccan (the time of rayed craters, similar to the lunar Copernican). The presence of geologically young cryovolcanic deposits on Ceres surface suggests that there could be warm melt pockets within Ceres shallow crust and the dwarf planet remain geologically active.

Discrete kinematic modeling of the 3-D deformation of sedimentary basins; Modelisation cinematique discrete de la deformation 3D des bassins sedimentaires

Energy Technology Data Exchange (ETDEWEB)

Cornu, T.

2001-01-01

The present work deals with three-dimensional deformation of sedimentary basins. The main goal of the work was to propose new ways to study tectonic deformation and to insert it into basin-modeling environment for hydrocarbon migration applications. To handle the complexity of the deformation, the model uses kinematic laws, a discrete approach, and the construction of a code that allows the greatest diversity in the deformation mechanisms we can take into account. The 3-D-volume deformation is obtained through the calculation of the behavior of the neutral surface of each basin layer. The main idea is to deform the neutral surface of each layer with the help of geometrical laws and to use the result to rebuild the volume deformation of the basin. The constitutive algorithm includes three characteristic features. The first one deals with the mathematical operator we use to describe the flexural-slip mechanism which is a combination of the translation of the neutral surface nodes and the rotation of the vertical edges attached to these nodes. This performs the reversibility that was required for the basin modeling. The second one is about. the use of a discrete approach, which gives a better description of the global deformation and offers to locally control volume evolutions. The knowledge of volume variations can become a powerful tool in structural geology analysis and the perfect complement for a field study. The last one concerns the modularity of the developed code. Indeed, the proposed model uses three main mechanisms of deformation. But the architecture of the code allows the insertion of new mechanisms or a better interaction between them. The model has been validated first with 2-D cases, then with 3-D natural cases. They give good results from a qualitative point of view. They also show the capacity of the model to provide a deformation path that is geologically acceptable, and its ability to control the volume variations of the basin through the

Geological characteristics of the main deposits in the world. Geological characteristics of French uranium deposits; their consequences on the different stages of valorisation. The uranium market

International Nuclear Information System (INIS)

Gangloff, A.; Lenoble, A.; Mabile, J.

1958-07-01

This document gathers three contributions. In the first one, after having recalled data regarding uranium ore and metal reserves in Canada, USA, South Africa and France, the author describes and discusses the geological and mineral characteristics of the main deposits in Canada (Great Bear Lake, Ace-Verna and other deposits of the Beaverlodge district, Gunnar, Blind River and Bancroft), in the USA (New Mexico, Colorado and Arizona), and in South Africa (similar structure as observed in Blind River). The second contribution addresses the French uranium deposits by firstly presenting, describing and classifying vein deposits (five types are distinguished) and sedimentary deposits in different geological formations, and by secondly discussing the impacts of these characteristics on exploration, surface exploration works, and mining works. The third contribution proposes an overview of the uranium market: comments of world productions (conventional extraction processes and technical peculiarities, costs and prices, reserves and production in Canada, USA, South Africa, France, Australia and others), presentation of the French program (location and production capacity of uranium production plants, locations of ore extraction), overview of the current situation of the world market (price levels, possible prices after 1962), discussion of the comparison between demands and supplies, overview of the French uranium policy

OneGeology - The most appropriate model to achieve access to up-to-date geoscience data using a distributed data system

Science.gov (United States)

Komac, Marko; Duffy, Tim; Robida, Francois; Harrison, Matt; Allison, Lee

2015-04-01

OneGeology is an initiative of Geological Survey Organisations (GSO) around the globe that dates back to Brighton, UK in 2007. Since then OneGeology has been a leader in developing geological online map data using a new international standard - a geological exchange language known as the 'GeoSciML' (currently version 3.2 exists, which enables instant interoperability of the data). Increased use of this new language allows geological data to be shared and integrated across the planet with other organisations. One of very important goals of OneGeology was a transfer of valuable know-how to the developing world, hence shortening the digital learning curve. In autumn 2013 OneGeology was transformed into a Consortium with a clearly defined governance structure, making its structure more official, its operability more flexible and its membership more open where in addition to GSO also to other type of organisations that manage geoscience data can join and contribute. The next stage of the OneGeology initiative will hence be focused into increasing the openness and richness of that data from individual countries to create a multi-thematic global geological data resource on the rocks beneath our feet. Authoritative information on hazards and minerals will help to prevent natural disasters, explore for resources (water, minerals and energy) and identify risks to human health on a planetary scale. With this new stage also renewed OneGeology objectives were defined and these are 1) to be the provider of geosciences data globally, 2) to ensure exchange of know-how and skills so all can participate, and 3) to use the global profile of 1G to increase awareness of the geosciences and their relevance among professional and general public. We live in a digital world that enables prompt access to vast amounts of open access data. Understanding our world, the geology beneath our feet and environmental challenges related to geology calls for accessibility of geoscience data and OneGeology

A preliminary global geologic map of Vesta based on Dawn Survey orbit data

Science.gov (United States)

Yingst, R.; Williams, D. A.; Garry, W. B.; Mest, S. C.; Petro, N. E.; Buczkowski, D.; Schenk, P.; Jaumann, R.; Pieters, C. M.; Roatsch, T.; Preusker, F.; Nathues, A.; LeCorre, L.; Reddy, V.; Russell, C. T.; Raymond, C. A.; DeSanctis, C.; Ammannito, E.; Filacchione, G.

2011-12-01

NASA's Dawn spacecraft arrived at the asteroid 4Vesta on July 15, 2011, and is now collecting imaging, spectroscopic, and elemental abundance data during its one-year orbital mission. As part of the geological analysis of the surface, we have utilized images and data from the Survey orbital sequence to produce a global map of Vesta's surface. Unit boundaries and feature characteristics were determined primarily from morphologic analysis of image data; projected Framing Camera (FC) images were used as the base map. Spectral information from FC and VIR are used to refine unit contacts and to separate compositional distinctions from differences arising from illumination or other factors. Those units that could be discerned both in morphology and in the color data were interpreted as geologically distinct units. Vesta's surface is highly-cratered; differences in color and albedo are possible indicators of varying thicknesses and areal extents of crater ejecta. The most prominent candidate impact feature dominates the south pole. This feature consists of a depression roughly circular in shape, with a central hill that is characterized by smoother texture and lower albedo distinctive from the lower-lying surrounding terrain. A complex network of deep troughs and ridges cuts through the floor of the feature. Many of these troughs trend north-south, while others appear circumferential to the hill and are truncated by or terminate at orthogonal ridges/grooves. Detailed mapping of these features will provide information on their orientations, possible origin(s), and their relationship, if any, to the central hill. The equator of Vesta is also girdled by a wide set of flat-floored troughs. Their orientation implies that their formation is related to the south polar structure. Several regions on Vesta have a concentration of craters displaying low-albedo interiors or exteriors. These craters may have an exogenic origin, or may be the result of excavation of a thin sub

Favorability for uranium in tertiary sedimentary rocks, southwestern Montana

International Nuclear Information System (INIS)

Wopat, M.A.; Curry, W.E.; Robins, J.W.; Marjaniemi, D.K.

1977-10-01

Tertiary sedimentary rocks in the basins of southwestern Montana were studied to determine their favorability for potential uranium resources. Uranium in the Tertiary sedimentary rocks was probably derived from the Boulder batholith and from silicic volcanic material. The batholith contains numerous uranium occurrences and is the most favorable plutonic source for uranium in the study area. Subjective favorability categories of good, moderate, and poor, based on the number and type of favorable criteria present, were used to classify the rock sequences studied. Rocks judged to have good favorability for uranium deposits are (1) Eocene and Oligocene strata and undifferentiated Tertiary rocks in the western Three Forks basin and (2) Oligocene rocks in the Helena basin. Rocks having moderate favorability consist of (1) Eocene and Oligocene strata in the Jefferson River, Beaverhead River, and lower Ruby River basins, (2) Oligocene rocks in the Townsend and Clarkston basins, (3) Miocene and Pliocene rocks in the Upper Ruby River basin, and (4) all Tertiary sedimentary formations in the eastern Three Forks basin, and in the Grasshopper Creek, Horse Prairie, Medicine Lodge Creek, Big Sheep Creek, Deer Lodge, Big Hole River, and Bull Creek basins. The following have poor favorability: (1) the Beaverhead Conglomerate in the Red Rock and Centennial basins, (2) Eocene and Oligocene rocks in the Upper Ruby River basin, (3) Miocene and Pliocene rocks in the Townsend, Clarkston, Smith River, and Divide Creek basins, (4) Miocene through Pleistocene rocks in the Jefferson River, Beaverhead River, and Lower Ruby River basins, and (5) all Tertiary sedimentary rocks in the Boulder River, Sage Creek, Muddy Creek, Madison River, Flint Creek, Gold Creek, and Bitterroot basins

Application of MSS/LANDSAT images to the structural study of recent sedimentary areas: Campos Sedimentary Basin, Rio de Janeiro, Brazil

Science.gov (United States)

Parada, N. D. J. (Principal Investigator); Barbosa, M. P.

1983-01-01

Visual and computer aided interpretation of MSS/LANDSAT data identified linear and circular features which represent the ""reflexes'' of the crystalline basement structures in the Cenozoic sediments of the emergent part of the Campos Sedimentary Basin.

Geology of Northwestern Switzerland - with special emphasis on Opalinus Clay

International Nuclear Information System (INIS)

Burkhard, M.

2007-01-01

This report describes the variations of the geological structures of Northwestern Switzerland during about the last 200 million years. This gives an explanation for the present partition of the different rock layers in the studied domain. The geology of Switzerland is dominated by the formation of the Alps. The Mont Terri geology is best explained within the framework of the tectonic Wilson cycle: assembly of Pangea in Late Paleozoic times culminating in the Variscan orogeny, collapse and decay of this earlier mountain chain, peneplanation and new rifting leading to the opening of the alpine Tethys Ocean during the Mesozoic, followed by plate convergence, subduction, collision and new mountain-building in the Neogene. The Mont Terri geology bears witness to the same suite of events as the Alps; tectonically speaking, Mont Terri is part of the Alps. Africa continues to push Apulia against the larger European plate and the question arises as to what the geological future has in store for our hills and mountains. Recent GPS (Global Positioning System) data Iead to believe that it will be just erosion and decay

Geology of the Nevada Test Site and nearby areas, southern Nevada

International Nuclear Information System (INIS)

Sinnock, S.

1982-10-01

The Department of Energy's Nevada Test Site (NTS) lies in the southern part of the Great Basin Section of the Basin and Range Physiographic Province. This report addresses the geological setting of the NTS in the context of the current waste isolation policy. The intent is to provide a synthesis of geological conditions at the NTS and nearby areas so that a general background of information is available for assessing the possible role of geology in providing protections for humans from buried radioactive wastes. The NTS is characterized by alluvium-filled, topgraphically closed valleys surrounded by ranges composed of Paleozoic sedimentary rocks and Tertiary volcanic tuffs and lavas. The Paleozoic rocks are a miogeosynclinal sequence of about 13,000 ft of pre-Cambrian to Cambrian clastic deposits (predominantly quartzites) overlain by about 14,000 ft of Cambrian through Devonian carbonates, 8000 ft of Mississippian argillites and quartzites, and 3000 ft of Pennsylvanian to Permian limestones. Tertiary volcanic rocks are predominatly silicic composition and were extruded from numerous eruptive centers during Miocene and Pliocene epochs. Within eruptive caldera depressions, volcanic deposits accumulated to perhaps 10,000 ft in total thickness, thinning to extinction outward from the calderas. Extrusion of minor amounts of basalts accompanied Pliocene and Pleistocene filling of structural basins with detritus from the ranges. Regional compressional and extensional structures as well as local volcanic structures occur in the NTS region. Normal extensional faulting coincided with the outbreak of volcanism during the Miocene and was superimposed on existing Mesozoic structures. Continued extensional deformation may be occurring at the present time

Global water cycle: geochemistry and environment

National Research Council Canada - National Science Library

Berner, Elizabeth Kay; Berner, Robert A

1987-01-01

.... The book provides an integrated approach to global geochemistry and environmental problems and introduces the reader to some fundamental concepts of geology, oceanography, meteorology, environmental...

Sorption and migration of neptunium in porous sedimentary materials

International Nuclear Information System (INIS)

Tanaka, Tadao; Mukai, Masayuki; Nakayama, Shinichi

2005-01-01

Column migration experiments of neptunium were conducted for porous sedimentary materials: coastal sand, tuffaceous sand, ando soil, reddish soil, yellowish soil and loess, and migration behavior, sorption mechanisms and chemical formation of Np were investigated. The migration behavior of Np in each material was much different each other, due to chemical formation in solution and/or sorption mechanism of Np. Mathematical models of different concepts were applied to the experimental results to interpret the sorption mechanism and the migration behavior. It can be concluded that both of instantaneous equilibrium sorption and sorption-desorption kinetics have to be considered to model the Np migration in sedimentary materials. (author)

A study about the long-term stability of sedimentary rock

International Nuclear Information System (INIS)

Yoshino, Naoto; Miyanomae, Shun-ichi; Inoue, Hiroyuki; Nashimoto, Yutaka

2005-02-01

In this paper, following two issues were examined and estimated, (1) the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, (2) the long term estimation of the dynamical behavior considering the condition of Horonobe area. As the study about the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, the thermal factor was focused on and the laboratory tests using test pieces which were sampled in Horonobe area were carried out under the water temperature were 20 degrees and 80 degrees. As a result, the time dependence parameter in variable-compliance-type constitutive-equation could be obtained. And comparison between creep property under 20 degrees and 80 degrees was conducted. In addition, the general properties of sedimentary soft rock under several conditions were identified by the survey of the literature. And the way how to confirm the dynamical properties of sedimentary soft rock with in-situ test were presented. For the study on the short-term and long-term stability of rock surrounding buffer materials, numerical simulations were carried out assuming several conditions. The direction of disposal tunnels and the ratio of rock strength by initial stress were estimated to be the main factor affecting the short-term stability of rock. Time dependency of rock and the stiffness of buffer material were estimated to be the main factor affecting the long-term stability of rock. (author)

Sedimentary cyclicity in early Pleistocene, evaporitic, playa-lake lacustrine deposits in the Guadix-Baza basin (Betic Cordillera, Spain); Ciclicidad sedimentaria en depositos lacustres evaporiticos tipo playa-lake del Pleistoceno inferior en la cuenca de Guadix-Baza (Cordillera Betica, Espana)

Energy Technology Data Exchange (ETDEWEB)

Garcia Aguilar, J. M.; Guera-Menchan, A.; Serrano, F.; Palmqvist, P.

2013-06-01

The Guadix-Baza basin (Betic Cordillera, southern Spain) contains in its eastern sector an early Pleistocene (Gelasian and lowermost Calabrian) sedimentary unit that was deposited in a shallow lacustrine environment. Given that the chronological limits of this unit lie between 2.5 and 1.6 Ma BP, the thickness of its preserved sediments (400 m) and high sedimentation rate (44.4 cm/ka) are remarkable. Numerous sedimentary cycles marked by an alternation of marls and sands are commonly found in the marginal sectors and marls and gypsum in the central sector, which would owe their origins to permanent flooding and evaporation/ re-flooding phases due to global climatic changes. Spectral analyses carried out using Fourier transform have revealed the existence of temporary frequencies associated with sedimentary cycles of between 0.2 and 5.2 ka. The origin of these cycles may be associated with variations in solar radiation and oscillations in the Moons orbital position, which would induce global climatic changes resulting in the rise and fall of the water table of the lake. Autocorrelation analyses conducted separately on the marly and evaporitic levels support this conclusion, as they indicate the existence of significant direct correlations between about 4 to 12 sedimentary cycles, which would correspond to repetitions of the stratigraphic series over a time span of 1.3 to 4 ka. (Author)

Thallium isotopes track fluctuations in global manganese oxide burial during the Ediacaran Period

Science.gov (United States)

Ostrander, C. M.; Nielsen, S.; Owens, J. D.; Jiang, G.; Planavsky, N.; Sahoo, S. K.; Zhang, F.; Lyons, T. W.; Anbar, A. D.

2017-12-01

Complex marine ecosystems appear in the geologic record for the first time during the Ediacaran (635 - 541 Ma), after the Marinoan Glaciation but before the Cambrian Explosion. Much debate surrounds the redox-state of global oceans during this diversification, with some arguing for pervasive anoxic conditions and others for increased oxygenation, including the possibility of episodic oxygen increases. Here, we use thallium (Tl) isotopes preserved in organic-rich shales from a deep-water section at Wuhe, South China, to track large-scale perturbations in Mn oxide burial during the Ediacaran. Changes to the Tl isotope composition of seawater over geologic timescales are driven dominantly by fluctuations in global Mn oxide burial, which require persistent O2 at the sediment-water interface. Importantly, the suite of sedimentary rocks analyzed is thought to have been deposited beneath persistent localized euxinia, which is an environment shown to effectively capture the Tl isotope composition of seawater. Within samples previously suggested to host oceanic oxygenation episodes (OOEs) because of high redox-sensitive element (RSE) enrichments (Sahoo et al. 2016, Geobiology), we find Tl isotope values as light as -5 epsilon units, which are indicative of removal of heavy Tl by Mn oxides elsewhere in the Ediacaran ocean and in-line with the presence of deep-marine O2. Intriguingly, between these events, during periods previously viewed as dominantly anoxic, we find Tl isotope excursions to values that are even lighter than during the OOEs (less than -10 epsilon units). To first order, these results imply that an even larger Mn oxide sink was present between the OOEs, which would require pervasive oceanic oxygenation. This interpretation is in direct conflict with interpretations of low RSE enrichments in these same samples, which invoke reservoir drawdown due to widespread anoxia—as well as many other data that suggest dominantly anoxic deep marine conditions through the

Proceedings of the 39. Brazilian congress on geology. v. 4

International Nuclear Information System (INIS)

1996-01-01

The book presents the 39. Brazilian Congress on Geology works, occurred in Salvador, Bahia, during the period of September 1 to 6, 1996. The meeting main subject - geology and society - reflects the current change epoch. The symposiums revealed the more important actions about geosciences applications to the society in the country. The round tables, structured for the polemical subject debates that involves the geosciences and the mineral sector crisis aspects, were achieved by several invited participants completely embraced with the subject. During the congress activities development there were some courses, technical excursions and external actions in Salvador, aiming to show the geosciences role to the social welfare. The symposiums presented papers about geology and the carstic terrains, paleo global change and environmental aspects in the thematic sections

Global stratigraphy. [of planet Mars

Science.gov (United States)

Tanaka, Kenneth L.; Scott, David H.; Greeley, Ronald

1992-01-01

Attention is given to recent major advances in the definition and documentation of Martian stratigraphy and geology. Mariner 9 provided the images for the first global geologic mapping program, resulting in the recognition of the major geologic processes that have operated on the planet, and in the definition of the three major chronostratigraphic divisions: the Noachian, Hesperian, and Amazonian Systems. Viking Orbiter images permitted the recognition of additional geologic units and the formal naming of many formations. Epochs are assigned absolute ages based on the densities of superposed craters and crater-flux models. Recommendations are made with regard to future areas of study, namely, crustal stratigraphy and structure, the highland-lowland boundary, the Tharsis Rise, Valles Marineris, channels and valley networks, and possible Martian oceans, lakes, and ponds.

Chapter B: Regional Geologic Setting of Late Cenozoic Lacustrine Diatomite Deposits, Great Basin and Surrounding Region: Overview and Plans for Investigation

Science.gov (United States)

Wallace, Alan R.

2003-01-01

Freshwater diatomite deposits are present in all of the Western United States, including the Great Basin and surrounding regions. These deposits are important domestic sources of diatomite, and a better understanding of their formation and geologic settings may aid diatomite exploration and land-use management. Diatomite deposits in the Great Basin are the products of two stages: (1) formation in Late Cenozoic lacustrine basins and (2) preservation after formation. Processes that favored long-lived diatom activity and diatomite formation range in decreasing scale from global to local. The most important global process was climate, which became increasingly cool and dry from 15 Ma to the present. Regional processes included tectonic setting and volcanism, which varied considerably both spatially and temporally in the Great Basin region. Local processes included basin formation, sedimentation, hydrology, and rates of processes, including diatom growth and accumulation; basin morphology and nutrient and silica sources were important for robust activity of different diatom genera. Only optimum combinations of these processes led to the formation of large diatomite deposits, and less than optimum combinations resulted in lakebeds that contained little to no diatomite. Postdepositional processes can destroy, conceal, or preserve a diatomite deposit. These processes, which most commonly are local in scale, include uplift, with related erosion and changes in hydrology; burial beneath sedimentary deposits or volcanic flows and tuffs; and alteration during diagenesis and hydrothermal activity. Some sedimentary basins that may have contained diatomite deposits have largely been destroyed or significantly modified, whereas others, such as those in western Nevada, have been sufficiently preserved along with their contained diatomite deposits. Future research on freshwater diatomite deposits in the Western United States and Great Basin region should concentrate on the regional

A three-dimensional model of the Pyrenees and their foreland basins from geological and gravimetric data

Science.gov (United States)

Wehr, H.; Chevrot, S.; Courrioux, G.; Guillen, A.

2018-06-01

We construct a three-dimensional geological model of the Pyrenees and their foreland basins with the Geomodeller. This model, which accounts for different sources of geological and geophysical informations, covers the whole Pyrenees, from the Atlantic Ocean to the Mediterranean Sea, and from the Iberian range to the Massif Central, down to 70 km depth. We model the geological structure with a stratigraphic column composed of a superposition of layers representing the mantle, lower, middle, and upper crusts. The sedimentary basins are described by two layers which allow us to make the distinction between Mesozoic and Cenozoic sediments, which are characterized by markedly different densities and seismic velocities. Since the Pyrenees result from the convergence between the Iberian and European plates, we ascribe to each plate its own stratigraphic column in order to be able to model the imbrication of Iberian and European crusts along this fossile plate boundary. We also introduce two additional units which describe the orogenic prism and the water column in the Bay of Biscay and in the Mediterranean Sea. The last ingredient is a unit that represents bodies of shallow exhumed and partly serpentinized lithospheric mantle, which are assumed to produce the positive Bouguer gravity anomalies in the North Pyrenean Zone. A first 3D model is built using only the geological information coming from geological maps, drill-holes, and seismic sections. We use the potential field method implemented in Geomodeller to interpolate these geological data. This model is then refined in order to better explain the observed Bouguer anomalies by adding new constraints on the main crustal interfaces. The final model explains the observed Bouguer anomalies with a standard deviation less than 3.4 mGal, and reveals anomalous deep structures beneath the eastern Pyrenees.

Commentary of Uruguay geological structure - Present status of its mining activity; Comentarios sobre conformacion geologica del Uruguay - Estado actual de su actividad minera

Energy Technology Data Exchange (ETDEWEB)

NONE

1988-07-01

This work is about the geological structure of Uruguay and its mining activity. The Rio de la Plata socket basin and the Rivera crystalline island are the oldest geochronological structures in Uruguay. This unit represents the 60% of the crystalline field and belongs to the Uruguay orogenetic Precambrian cycle. In the north there are sedimentary rocks and granites of the Upper Precambrian period.The mining and processing of marble, granite, agate, amethyst and metallic minerals are declared of national interest.

Paleogene Vertebrate Paleontology, Geology and Remote Sensing in the Wind River Basin

Science.gov (United States)

Stucky, R. K.; Krishtalka, L.

1985-01-01

Biostratigraphic and lithostratigraphic studies were used to correlate different events in the geologic evolution of the northeastern part of the Wind River Basin and have suggested several conclusions. Laterally equivalent exposures of the Lysite member from Cedar Ridge to Bridger Creek show a gradation in lithology from interbedded boulder conglomerates and sandstones to interbedded lenticular sandstones and mudstones to interbedded carbonaceous shales, coals and tabular sandstones. This gradation suggests a shift from alluvial fan to braided stream to paludal or lacustrine sedimentary environments during the late early Eocene. The Lysite and Lost Cabin members of the Wind River Formation are in fault contact in the Bridger Creek area and may intertongue to the east along Cedar Ridge. Ways in which remote sensing could be used in these studies are discussed.

Correlation between Bieniawski’s RMR index and Barton’s Q index in fine-grained sedimentary rock formations

Directory of Open Access Journals (Sweden)

J. D. Fernández-Gutiérrez

2017-09-01

Full Text Available From the XX century, various rock mass classification systems have been proposed. Among them, the Bieniawski’s RMR system and Barton’s Q system have emerged as the most used rock mass classification worldwide. Correlations between both indices have been proposed, usually with a wide scattering of the data used in deriving the equations. However, it has been observed that correlations established for a specific geological unit fit better. The aim of this paper is to propose a correlation between RMR and Q indices for fine-grained sedimentary rock formations, normally found in the area of Bilbao (Spain, by means of the collected data during the excavation of the tunnel Etxebarri-Casco Viejo of the line 3 of the Metropolitan Railway of Bilbao. Obtained equation shows a high correlation coefficient and a unique relationship between the two classification systems has been proposed, not depending on the choice of the independent variable.

Study on origin and sedimentary environment of marine sediments from Kii Channel, Hiroshima Bay and Tosa Bay

International Nuclear Information System (INIS)

Suzuki, Misaki

2008-01-01

The trace amounts of elements in the sediments of sea bottom in Kii Channel, Hiroshima Bay and Tosa Bay were determined quantitatively by the neutron activation analysis. The following facts were illustrated particularly from the quantitative analysis of scandium, rare earths, thorium and uranium: 1) It was known from Ce/La ratio that the geological feature in the west part of Japan is reflected in Kii Channel, Hiroshima Bay and Tosa Bay; 2) The rare-earth element pattern and La/Lu ratio suggest the fact that Kii Channel, Hiroshima Bay and Tosa Bay are essentially composed of the materials of which origin is land; 3) From the fact that Ce/La ratio in these sites are slightly under 1.0, these sites are considered to be affected mainly by the materials of which origin is land; 4) The sedimentary environment in the marine bottom of the Japanese coasts has been found to be mostly under a reductive state. (M.H.)

OneGeology - a geoscience exemplar for worldwide cyberinfrastructure capacity-building and scientific innovation

Science.gov (United States)

van Daalen, T.; Allison, M. L.

2012-12-01

OneGeology is a trail-blazing global initiative that has helped propel the geosciences into the forefront of cyberinfrastructure development with potentially transformative impacts on scientific and technical innovation across broad areas of society. In the five years since its launch, 117 nations, through their Geological Surveys have signed the OneGeology protocols and nearly half are serving up national geological maps as Web services at varying scales, with the remainder developing those capabilities. In federal systems, states and provinces are increasingly adding higher resolution spatial data to the national contributions to the global system. The OneGeology concept of a distributed, open-source, Web-service based network has become the archetype for transforming data into knowledge and innovation. This is not only revolutionizing the geosciences but offering opportunities for governments to use these cutting-edge capabilities for broad innovation and capacity building. Across the globe, communities are facing the same four challenges: put simply, how do we best make data discoverable, shareable, viewable and downloadable, so that the user also has access to consistent data at a national and continental level? The principle of managing scientific and societal data and knowledge where they are generated and are best understood is well established in the geoscience community and can be scaled up and transferred to other domains and sectors of society. The distributed nature of most data sources means the complementary delivery mechanism of Web map services has become equally prevalent in the spatial data community. Together these factors are driving a world-wide revolution in the way spatial information is being disseminated to its users. Industry, academia, and governments are quickly adopting and adapting to this new paradigm and discovering that very modest investments in this emerging field are reaping tremendous returns in national capacity and triggering

Geological implications of radium and helium in oil-field brines: observations, inferences and speculations

International Nuclear Information System (INIS)

Lerche, I.

1993-01-01

The 1600 yr half-life of radium restricts the time and thus the distance over which radium can migrate in sediments. The dominant source of unsupported radium in sandstone reservoir brines must then be close by and is likely in shales adjacent to the oil-field reservoirs. The chemical similarity of calcium and radium can be used to argue for a local shale-source contribution to the calcium in reservoir sands -suggesting the probability of calcite cementation early in the sedimentary sequence. Helium production by radium decay increases with time. Concentrations of helium found in reservoir oil field brines are then used to suggest that: (a) such reservoirs are dominantly closed systems over geological times; (b) neither methane nor helium in the reservoirs have migrated any significant distance; and (c) the mechanism responsible for the observed helium in the brine is a continuous on-going process operative today. Diagenetic studies should then deal with both sands and shales interdependently, the two are not separable. Shales control the transport mechanisms of migration so that the primary migration of hydrocarbons, the result of kerogen catagenesis in shales, should occur sufficiently early in the sedimentary sequence in order to avoid exclusion from the reservoir by calcite cementation in association with radium transport. (author)

The mineralogy and petrology of I-type cosmic spherules: Implications for their sources, origins and identification in sedimentary rocks

Science.gov (United States)

Genge, Matthew J.; Davies, Bridie; Suttle, Martin D.; van Ginneken, Matthias; Tomkins, Andrew G.

2017-12-01

I-type cosmic spherules are micrometeorites that formed by melting during atmospheric entry and consist mainly of iron oxides and FeNi metal. I-types are important because they can readily be recovered from sedimentary rocks allowing study of solar system events over geological time. We report the results of a study of the mineralogy and petrology of 88 I-type cosmic spherules recovered from Antarctica in order to evaluate how they formed and evolved during atmospheric entry, to constrain the nature of their precursors and to establish rigorous criteria by which they may be conclusively identified within sediments and sedimentary rocks. Two textural types of I-type cosmic spherule are recognised: (1) metal bead-bearing (MET) spherules dominated by Ni-poor (100 and suggest that metal from H-group ordinary, CM, CR and iron meteorites may form the majority of particles. Oxidation during entry heating increases in the series MET 80 wt% Ni comprising a particle mass fraction of exchange of Ni between wüstite and metal, and magnetite and wüstite are suggested as proxies for the rate of oxidation and cooling rate respectively. Variations in magnetite and wüstite crystal sizes are also suggested to relate to cooling rate allowing relative entry angle of particles to be evaluated. The formation of secondary metal in the form of sub-micron Ni-rich or Pt-group nuggets and as symplectite with magnetite was also identified and suggested to occur largely due to the exsolution of metallic alloys during decomposition of non-stoichiometric wüstite. Weathering is restricted to replacement of metal by iron hydroxides. The following criteria are recommended for the conclusive identification of I-type spherules within sediments and sedimentary rocks: (i) spherical particle morphologies, (ii) dendritic crystal morphologies, (iii) the presence of wüstite and magnetite, (iv) Ni-bearing wüstite and magnetite, and (v) the presence of relict FeNi metal.

Onshore/ Offshore Geologic Assessment for Carbon Storage in the Southeastern United States

Science.gov (United States)

Knapp, C. C.; Knapp, J. H.; Brantley, D.; Lakshmi, V.; Almutairi, K.; Almayahi, D.; Akintunde, O. M.; Ollmann, J.

2017-12-01

Eighty percent of the world's energy relies on fossil fuels and under increasingly stricter national and international regulations on greenhouse gas emissions storage of CO2 in geologic repositories seems to be not only a feasible, but also and vital solution for near/ mid-term reduction of carbon emissions. We have evaluated the feasibility of CO2 storage in saline formations of the Eastern North American Margin (ENAM) including (1) the Jurassic/Triassic (J/TR) sandstones of the buried South Georgia Rift (SGR) basin, and (2) the Mesozoic and Cenozoic geologic formations along the Mid- and South Atlantic seaboard. These analyses have included integration of subsurface geophysical data (2- and 3-D seismic surveys) with core samples, well logs as well as uses of geological databases and geospatial analysis leading to CO2 injection simulation models. ENAM is a complex and regionally extensive mature Mesozoic passive margin rift system encompassing: (1) a large volume and regional extent of related magmatism known as the Central Atlantic Magmatic Province (CAMP), (2) a complete stratigraphic column that records the post-rift evolution in several basins, (3) preserved lithospheric-scale pre-rift structures including Paleozoic sutures, and (4) a wide range of geological, geochemical, and geophysical studies both onshore and offshore. While the target reservoirs onshore show heterogeneity and a highly complex geologic evolution they also show promising conditions for significant safe CO2 storage away from the underground acquifers. Our offshore study (the Southeast Offshore Storage Resource Assessment - SOSRA) is focused on the outer continental shelf from North Carolina to the southern tip of Florida. Three old exploration wells are available to provide additional constraints on the seismic reflection profiles. Two of these wells (TRANSCO 1005-1 and COST GE-1) penetrate the pre-rift Paleozoic sedimentary formations while the EXXON 564-1 well penetrates the post

Estimating tectonic history through basin simulation-enhanced seismic inversion: Geoinformatics for sedimentary basins

Science.gov (United States)

Tandon, K.; Tuncay, K.; Hubbard, K.; Comer, J.; Ortoleva, P.

2004-01-01

A data assimilation approach is demonstrated whereby seismic inversion is both automated and enhanced using a comprehensive numerical sedimentary basin simulator to study the physics and chemistry of sedimentary basin processes in response to geothermal gradient in much greater detail than previously attempted. The approach not only reduces costs by integrating the basin analysis and seismic inversion activities to understand the sedimentary basin evolution with respect to geodynamic parameters-but the technique also has the potential for serving as a geoinfomatics platform for understanding various physical and chemical processes operating at different scales within a sedimentary basin. Tectonic history has a first-order effect on the physical and chemical processes that govern the evolution of sedimentary basins. We demonstrate how such tectonic parameters may be estimated by minimizing the difference between observed seismic reflection data and synthetic ones constructed from the output of a reaction, transport, mechanical (RTM) basin model. We demonstrate the method by reconstructing the geothermal gradient. As thermal history strongly affects the rate of RTM processes operating in a sedimentary basin, variations in geothermal gradient history alter the present-day fluid pressure, effective stress, porosity, fracture statistics and hydrocarbon distribution. All these properties, in turn, affect the mechanical wave velocity and sediment density profiles for a sedimentary basin. The present-day state of the sedimentary basin is imaged by reflection seismology data to a high degree of resolution, but it does not give any indication of the processes that contributed to the evolution of the basin or causes for heterogeneities within the basin that are being imaged. Using texture and fluid properties predicted by our Basin RTM simulator, we generate synthetic seismograms. Linear correlation using power spectra as an error measure and an efficient quadratic

Reconnaissance geologic map of the Hyampom 15' quadrangle, Trinity County, California

Science.gov (United States)

Irwin, William P.

2010-01-01

The Hyampom 15' quadrangle lies west of the Hayfork 15' quadrangle in the southern part of the Klamath Mountains geologic province of northern California. It spans parts of four generally northwest-trending tectono- stratigraphic terranes of the Klamath Mountains, the Eastern Hayfork, Western Hayfork, Rattlesnake Creek, and Western Jurassic terranes, as well as, in the southwest corner of the quadrangle, a small part of the Pickett Peak terrane of the Coast Range province. Remnants of the Cretaceous Great Valley overlap sequence that once covered much of the pre-Cretaceous bedrock of the quadrangle are now found only as a few small patches in the northeast corner of the quadrangle. Fluvial and lacustrine deposits of the mid-Tertiary Weaverville Formation crop out in the vicinity of the village of Hyampom. The Eastern Hayfork terrane is a broken formation and m-lange of volcanic and sedimentary rocks that include blocks of chert and limestone. The chert has not been sampled; however, chert from the same terrane in the Hayfork quadrangle contains radiolarians of Permian and Triassic ages, but none clearly of Jurassic age. Limestone at two localities contains late Paleozoic foraminifers. Some of the limestone from the Eastern Klamath terrane in the Hayfork quadrangle contains faunas of Tethyan affinity. The Western Hayfork terrane is part of an andesitic volcanic arc that was accreted to the western edge of the Eastern Hayfork terrane. It consists mainly of metavolcaniclastic andesitic agglomerate and tuff, as well as argillite and chert, and it includes the dioritic Ironside Mountain batholith that intruded during Middle Jurassic time (about 170 Ma). This intrusive body provides the principal constraint on the age of the terrane. The Rattlesnake Creek terrane is a melange consisting mostly of highly dismembered ophiolite. It includes slabs of serpentinized ultramafic rock, basaltic volcanic rocks, radiolarian chert of Triassic and Jurassic ages, limestone containing

Provenance and geological significance of red mud and other clastic sediments of the Mugnano cave (Montagnola Senese, Italy

Directory of Open Access Journals (Sweden)

Iacoviello Francesco

2012-07-01

Full Text Available The Mugnano cave is characterized by a thick clastic sedimentary fill showing a great variability of sedimentary facies, ranging from clay to coarse-grained sand deposits. This paper deals with combined sedimentological and mineralogical (XRD and SEM studies of these sediments and bedrock insoluble residues in order to understand the origin and geological significance of cave deposits, with particular attention to red mud sediments, often considered as the residue of host rock dissolution. Three different sedimentary facies were recognized: i YS, yellow sand with occasionally shell fragments, testifying the arrival of sediments from the surrounding landscape; ii RS, red laminated mud; iii GS, grey and red-grey mud and sand, dolomite-rich sediments. Furthermore, the results obtained in the present study allowed the identification of two fingerprint minerals: i quartz, present only as traces in the limestone host-rock, and ii dolomite, certainly related to the incomplete bedrock dissolution. Results obtained by this multidisciplinary approach testify that no one of the investigated sediments is representative of a completely autochthonous sedimentation (i.e. accumulation of insoluble residue of limestone in a cave environment. In fact, all the three sedimentary facies show a bulk composition rich in quartz, a mineral indicating an external origin for these sediments. Also the grey sediments, despite of their high content of bedrock- related dolomite, are quite rich in quartz and they testify the mixing of autochthonous and allocthonous sediments. The clay fraction of cave sediments shows strong compositional similarities with bedrock insoluble residue and consequently its analysis cannot be considered as a clear proxy for distinguishing between different parent materials. Therefore, the origin of these cave deposits is dominantly related to external sediments inputs, with terra rossa surface soils as the most probable parent material for red mud

Geologic map of the Big Delta B-2 quadrangle, east-central Alaska

Science.gov (United States)

Day, Warren C.; Aleinikoff, John N.; Roberts, Paul; Smith, Moira; Gamble, Bruce M.; Henning, Mitchell W.; Gough, Larry P.; Morath, Laurie C.

2003-01-01

New 1:63,360-scale geologic mapping of the Big Delta B-2 quadrangle provides important data on the structural setting and age of geologic units, as well as on the timing of gold mineralization plutonism within the Yukon-Tanana Upland of east-central Alaska. Gold exploration has remained active throughout the region in response to the discovery of the Pogo gold deposit, which lies within the northwestern part of the quadrangle near the south bank of the Goodpaster River. Geologic mapping and associated geochronological and geochemical studies by the U.S. Geological Survey (USGS) and the Alaska Department of Natural Resources, Division of Mining and Water Management, provide baseline data to help understand the regional geologic framework. Teck Cominco Limited geologists have provided the geologic mapping for the area that overlies the Pogo gold deposit as well as logistical support, which has lead to a much improved and informative product. The Yukon-Tanana Upland lies within the Tintina province in Alaska and consists of Paleozoic and possibly older(?) supracrustal rocks intruded by Paleozoic (Devonian to Mississippian) and Cretaceous plutons. The oldest rocks in the Big Delta B-2 quadrangle are Paleozoic gneisses of both plutonic and sedimentary origin. Paleozoic deformation, potentially associated with plutonism, was obscured by intense Mesozoic deformation and metamorphism. At least some of the rocks in the quadrangle underwent tectonism during the Middle Jurassic (about 188 Ma), and were subsequently deformed in an Early Cretaceous contractional event between about 130 and 116 Ma. New U-Pb SHRIMP data presented here on zircons from the Paleozoic biotite gneisses record inherited cores that range from 363 Ma to about 2,130 Ma and have rims of euhedral Early Cretaceous metamorphic overgrowths (116 +/- 4 Ma), interpreted to record recrystallization during Cretaceous west-northwest-directed thrusting and folding. U-Pb SHRIMP dating of monazite from a Paleozoic

Pore-scale studies of multiphase flow and reaction involving CO2 sequestration in geologic formations

Science.gov (United States)

Kang, Q.; Wang, M.; Lichtner, P. C.

2008-12-01

In geologic CO2 sequestration, pore-scale interfacial phenomena ultimately govern the key processes of fluid mobility, chemical transport, adsorption, and reaction. However, spatial heterogeneity at the pore scale cannot be resolved at the continuum scale, where averaging occurs over length scales much larger than typical pore sizes. Natural porous media, such as sedimentary rocks and other geological media encountered in subsurface formations, are inherently heterogeneous. This pore-scale heterogeneity can produce variabilities in flow, transport, and reaction processes that take place within a porous medium, and can result in spatial variations in fluid velocity, aqueous concentrations, and reaction rates. Consequently, the unresolved spatial heterogeneity at the pore scale may be important for reactive transport modeling at the larger scale. In addition, current continuum models of surface complexation reactions ignore a fundamental property of physical systems, namely conservation of charge. Therefore, to better understand multiphase flow and reaction involving CO2 sequestration in geologic formations, it is necessary to quantitatively investigate the influence of the pore-scale heterogeneity on the emergent behavior at the field scale. We have applied the lattice Boltzmann method to simulating the injection of CO2 saturated brine or supercritical CO2 into geological formations at the pore scale. Multiple pore-scale processes, including advection, diffusion, homogeneous reactions among multiple aqueous species, heterogeneous reactions between the aqueous solution and minerals, ion exchange and surface complexation, as well as changes in solid and pore geometry are all taken into account. The rich pore scale information will provide a basis for upscaling to the continuum scale.

A spatial database of bedding attitudes to accompany Geologic map of the greater Denver area, Front Range Urban Corridor, Colorado

Science.gov (United States)

Trimble, Donald E.; Machette, Michael N.; Brandt, Theodore R.; Moore, David W.; Murray, Kyle E.

2003-01-01

This digital map shows bedding attitude symbols display over the geographic extent of surficial deposits and rock stratigraphic units (formations) as compiled by Trimble and Machette 1973-1977 and published in 1979 (U.S. Geological Survey Map I-856-H) under the Front Range Urban Corridor Geology Program. Trimble and Machette compiled their geologic map from published geologic maps and unpublished geologic mapping having varied map unit schemes. A convenient feature of the compiled map is its uniform classification of geologic units that mostly matches those of companion maps to the north (USGS I-855-G) and to the south (USGS I-857-F). Published as a color paper map, the Trimble and Machette map was intended for land-use planning in the Front Range Urban Corridor. This map recently (1997-1999), was digitized under the USGS Front Range Infrastructure Resources Project (see cross-reference). In general, the mountainous areas in the west part of the map exhibit various igneous and metamorphic bedrock units of Precambrian age, major faults, and fault brecciation zones at the east margin (5-20 km wide) of the Front Range. The eastern and central parts of the map (Colorado Piedmont) depict a mantle of unconsolidated deposits of Quaternary age and interspersed outcroppings of Cretaceous or Tertiary-Cretaceous sedimentary bedrock. The Quaternary mantle is comprised of eolian deposits (quartz sand and silt), alluvium (gravel, sand, and silt of variable composition), colluvium, and few landslides. At the mountain front, north-trending, dipping Paleozoic and Mesozoic sandstone, shale, and limestone bedrock formations form hogbacks and intervening valleys.

Sedimentary Environments Offshore Norway - Palaeozoic to Recent

Energy Technology Data Exchange (ETDEWEB)

Martinsen, Ole J.; Dreyer, Tom [eds.

1999-07-01

The report includes the extended abstracts from the conference, 71 in number. The presentations discuss the sedimentary characteristics of the North Sea area and the the methods used in the research, a thorough knowledge of which is important for economic exploration of the oil and gas resources of the North Sea.

Global Positioning System data collection, processing, and analysis conducted by the U.S. Geological Survey Earthquake Hazards Program

Science.gov (United States)

Murray, Jessica R.; Svarc, Jerry L.

2017-01-01

The U.S. Geological Survey Earthquake Science Center collects and processes Global Positioning System (GPS) data throughout the western United States to measure crustal deformation related to earthquakes and tectonic processes as part of a long‐term program of research and monitoring. Here, we outline data collection procedures and present the GPS dataset built through repeated temporary deployments since 1992. This dataset consists of observations at ∼1950 locations. In addition, this article details our data processing and analysis procedures, which consist of the following. We process the raw data collected through temporary deployments, in addition to data from continuously operating western U.S. GPS stations operated by multiple agencies, using the GIPSY software package to obtain position time series. Subsequently, we align the positions to a common reference frame, determine the optimal parameters for a temporally correlated noise model, and apply this noise model when carrying out time‐series analysis to derive deformation measures, including constant interseismic velocities, coseismic offsets, and transient postseismic motion.

Sedimentary condensation and authigenesis

Science.gov (United States)

Föllmi, Karl

2016-04-01

Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin ( 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and paleoenvironmental change themselves.

Time Matters: Increasing the Efficiency of Antarctic Marine Geology and Paleoceanography Expeditions by Providing Improved Sediment Chronology

Science.gov (United States)

Rosenheim, B. E.; Domack, E. W.; Shevenell, A.; Subt, C.

2015-12-01

To maximize the areal extent of Antarctic sedimentary records of past deglaciation, it is necessary to ensure more sediment cores can be adequately dated. Antarctic margin sediment is challenging to date due to the lack of preserved calcium carbonate, but the records contained in these sediments readily recount the history of deglaciation. Recent and continued development of new chronological methods for Antarctic margin sediments have allowed better use of the efforts of marine geological coring expeditions to the region. The development of Ramped PyrOx radiocarbon dating has allowed us to 1. improve dates in deglacial sediments where no carbonate is preserved, 2. date glacial sediments lying below the tills marking the last glaciation, and 3. compile core chronologies into a regional framework of ice shelf collapse that has eluded many marine geology campaigns over the last few decades. These advances in a fundamental aspect of geological sciences will put the U.S. and international community on a better foothold to interpret the past as it relates to our warming future. We will present these advances in chronology as well as the science that is enabled by them, while arguing that the future of Antarctic marine science also depends on investments in shore-based technologies that come at a relatively low cost.

Geology and sinkhole development of the Hagerstown valley : phase II : [research summary].

Science.gov (United States)

2014-06-01

The objective of this study was to map the western half of the Hagerstown Valley to : determine the distribution of karst features relative to bedrock geologic units using a : global positioning system (GPS).

Marine Geology and Geophysics Field Course Offered by The University of Texas Institute for Geophysics

Science.gov (United States)

Duncan, D.; Davis, M. B.; Allison, M. A.; Gulick, S. P.; Goff, J. A.; Saustrup, S.

2012-12-01

The University of Texas Institute for Geophysics, part of the Jackson School of Geosciences, annually offers an intensive three-week marine geology and geophysics field course during the spring-summer intersession. Now in year six, the course provides hands-on instruction and training for graduate and upper-level undergraduate students in data acquisition, processing, interpretation, and visualization. Techniques covered include high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, several types of sediment coring, grab sampling, and the sedimentology of resulting seabed samples (e.g., core description, grain size analysis, x-radiography, etc.). Students participate in an initial period of classroom instruction designed to communicate geological context of the field area (which changes each year) along with theoretical and technical background on each field method. The class then travels to the Gulf Coast for a week of at-sea field work. Our field sites at Port Aransas and Galveston, Texas, and Grand Isle, Louisiana, have provided ideal locations for students to investigate coastal and sedimentary processes of the Gulf Coast and continental shelf through application of geophysical techniques. In the field, students rotate between two research vessels: one vessel, the 22' aluminum-hulled R/V Lake Itasca, owned and operated by UTIG, is used principally for multibeam bathymetry, sidescan sonar, and sediment sampling; the other, NOAA's R/V Manta or the R/V Acadiana, operated by the Louisiana Universities Marine Consortium, and is used primarily for high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, gravity coring, and vibrocoring. While at sea, students assist with survey design, learn instrumentation set up, acquisition parameters, data quality control, and safe instrument deployment and retrieval. In teams of three, students work in onshore field labs preparing sediment samples for

Age and sedimentary record of inland eolian sediments in Lithuania, NE European Sand Belt

DEFF Research Database (Denmark)

Kalińska-Nartiša, Edyta; Thiel, Christine; Nartišs, Maris

2015-01-01

in any detail. The sedimentary structural-textural features are investigated and a chronology was derived using optically stimulated luminescence on both quartz and feldspar. The sedimentary structures and the rounding and surface characteristics of the quartz grains argue for a predominance of eolian...

Geology and potency of Uranium mineralization occurrences in Harau area, West Sumatera

International Nuclear Information System (INIS)

Ngadenin

2013-01-01

The Background of this study is due to the geological setting of Harau area and its surrounding, West Sumatera, that is identified as a favourable area for uranium accumulation which is indicated by the presence of anomalous radioactivity in the Tertiary sedimentary rocks deposited on the terrestrial environment and the presence of anomalous uranium contents in Pre-Tertiary granites in several places in West Sumatera, and the presence of radioactivity anomalous in the Pre Tertiary metamorphic rocks. The purpose of this study is to determine the potential formation of uranium mineralization in the Harau area, to be used as a basis to conduct more detailed research in order to inventory the potential of uranium resources in Indonesia. The scope of the discussion in this review includes a discussion of geology, geochemistry and radioactivity of the outcrops. The composition of regional stratigraphic from old to young is quartzite unit, phyllite unit, conglomerate unit, sandstone unit, tuff unit and alluvium river. The main fault that developed in the study area are normal faults trending southwest – northeast. The study area is splitted into two sections where the southeastern part relatives fall down of the northwest. Based on geological setting, radioactivity and uranium data then is assumed that Harau is a potential area for the formation of uranium mineralization in sandstone and its vein type. Sandstone type is expected occur in sandstone conglomerate unit of The Brani Formation and vein type is expected occur in the quartzite unit of The Kuantan Formation. (author)

Regional mantle upwelling on Venus: The Beta-Atla-Themis anomaly and correlation with global tectonic patterns

Science.gov (United States)

Crumpler, L. S.; Head, J. W.; Aubele, Jayne C.

1993-01-01

The morphology and global distribution of volcanic centers and their association with other geological characteristics offers significant insight into the global patterns of geology, tectonic style, thermal state, and interior dynamics of Venus. Magellan data permit the detailed geological interpretation necessary to address questions about interior dynamics of Venus particularly as they reflect relatively physical, chemical, and thermal conditions of the interior. This paper focuses on the distribution of anomalous concentrations of volcanic centers on Venus and regional patterns of tectonic deformation as it may relate to the identification of global internal anomalies, including mantle dynamic, petrological, or thermal patterns.

California Geological Survey Geologic Map Index

Data.gov (United States)

California Natural Resource Agency — All the individual maps from the Geologic Atlas of California and the Regional Geologic map series have been georeferenced for display in a GIS (and viewable online...

Inverse modeling of geochemical and mechanical compaction in sedimentary basins

Science.gov (United States)

Colombo, Ivo; Porta, Giovanni Michele; Guadagnini, Alberto

2015-04-01

We study key phenomena driving the feedback between sediment compaction processes and fluid flow in stratified sedimentary basins formed through lithification of sand and clay sediments after deposition. Processes we consider are mechanic compaction of the host rock and the geochemical compaction due to quartz cementation in sandstones. Key objectives of our study include (i) the quantification of the influence of the uncertainty of the model input parameters on the model output and (ii) the application of an inverse modeling technique to field scale data. Proper accounting of the feedback between sediment compaction processes and fluid flow in the subsurface is key to quantify a wide set of environmentally and industrially relevant phenomena. These include, e.g., compaction-driven brine and/or saltwater flow at deep locations and its influence on (a) tracer concentrations observed in shallow sediments, (b) build up of fluid overpressure, (c) hydrocarbon generation and migration, (d) subsidence due to groundwater and/or hydrocarbons withdrawal, and (e) formation of ore deposits. Main processes driving the diagenesis of sediments after deposition are mechanical compaction due to overburden and precipitation/dissolution associated with reactive transport. The natural evolution of sedimentary basins is characterized by geological time scales, thus preventing direct and exhaustive measurement of the system dynamical changes. The outputs of compaction models are plagued by uncertainty because of the incomplete knowledge of the models and parameters governing diagenesis. Development of robust methodologies for inverse modeling and parameter estimation under uncertainty is therefore crucial to the quantification of natural compaction phenomena. We employ a numerical methodology based on three building blocks: (i) space-time discretization of the compaction process; (ii) representation of target output variables through a Polynomial Chaos Expansion (PCE); and (iii) model

Natural climate variations in a geological perspective

International Nuclear Information System (INIS)

Mikkelsen, N.; Kuijpers, A.

2001-01-01

The climate is constantly changing, and it has been changing throughout the geological history of the Earth. These natural changes have shown a variability with frequencies from millions of years to just a few hundreds or tens of years. Some of the variations have been rather dramatic - shifting from globally uniform and hot climates to regular ice ages - whereas other changes have been less spectacular. All natural climate variations have an impact on the physical and biological systems of the Earth - and on mankind and culture during the last hundred thousand years. In this chapter we shall discuss the natural climate changes that has taken place during the geological history of the Earth and comment on the impact of these changes on the cultural evolution of mankind with special emphasis on Greenland. (LN)

Sedimentary organic matter variations in the Chukchi Borderland over the last 155 kyr

Science.gov (United States)

Rella, S. F.; Uchida, M.

2011-03-01

Knowledge on past variability of sedimentary organic carbon in the Arctic Ocean is important to assess natural carbon cycling and transport processes related to global climate changes. However, the late Pleistocene oceanographic history of the Arctic is still poorly understood. In the present study we show sedimentary records of total organic carbon (TOC), C/N and CaCO3 from a piston core recovered from the northern Northwind Ridge in the far western Arctic Ocean, a region potentially sensitively responding to past variability in surface current regimes and sedimentary processes such as coastal erosion. An age model based on correlation of our CaCO3 record with the benthic δ18O stack, supplemented by lithological constraints, suggests that the piston core records paleoenvironmental changes of the last 155 kyr. According to this age model, TOC and C/N show orbital-scale increases and decreases that can be respectively correlated to the waxing and waning of large ice sheets dominating the Eurasian Arctic, suggesting advection of fine suspended matter derived from glacial erosion to the Northwind Ridge by eastward flowing intermediate water and/or surface water and sea ice during cold episodes of the last two glacial-interglacial cycles. At millennial scales, increases in TOC and C/N appear to correlate to a suite of Dansgaard-Oeschger Stadials between 120 and 40 ka before present (BP) and thus seem to respond to abrupt northern hemispheric temperature changes. Between 65 and 40 ka BP, closures and openings of the Bering Strait could have additionally influenced TOC and C/N variability. CaCO3 content tends to anti-correlate with TOC and C/N on both orbital and millennial time scales, which we interpret as enhanced sediment advection from the carbonate-rich Canadian Arctic via an extended Beaufort Gyre during warm periods of the last two glacial-interglacial cycles and increased terrestrial organic carbon advection from the Siberian Arctic during cold periods when the

Sedimentary architecture and chronostratigraphy of a late Quaternary incised-valley fill: A case study of the late Middle and Late Pleistocene Rhine system in the Netherlands

Science.gov (United States)

Peeters, J.; Busschers, F. S.; Stouthamer, E.; Bosch, J. H. A.; Van den Berg, M. W.; Wallinga, J.; Versendaal, A. J.; Bunnik, F. P. M.; Middelkoop, H.

2016-01-01

This paper describes the sedimentary architecture, chronostratigraphy and palaeogeography of the late Middle and Late Pleistocene (Marine Isotope Stage/MIS 6-2) incised Rhine-valley fill in the central Netherlands based on six geological transects, luminescence dating, biostratigraphical data and a 3D geological model. The incised-valley fill consists of a ca. 50 m thick and 10-20 km wide sand-dominated succession and includes a well-developed sequence dating from the Last Interglacial: known as the Eemian in northwest Europe. The lower part of the valley fill contains coarse-grained fluvio-glacial and fluvial Rhine sediments that were deposited under Late Saalian (MIS 6) cold-climatic periglacial conditions and during the transition into the warm Eemian interglacial (MIS 5e-d). This unit is overlain by fine-grained fresh-water flood-basin deposits, which are transgressed by a fine-grained estuarine unit that formed during marine high-stand. This ca. 10 m thick sequence reflects gradual drowning of the Eemian interglacial fluvial Rhine system and transformation into an estuary due to relative sea-level rise. The chronological data suggests a delay in timing of regional Eemian interglacial transgression and sea-level high-stand of several thousand years, when compared to eustatic sea-level. As a result of this glacio-isostatic controlled delay, formation of the interglacial lower deltaic system took only place for a relative short period of time: progradation was therefore limited. During the cooler Weichselian Early Glacial period (MIS 5d-a) deposition of deltaic sediments continued and extensive westward progradation of the Rhine system occurred. Major parts of the Eemian and Weichselian Early Glacial deposits were eroded and buried as a result of sea-level lowering and climate cooling during the early Middle Weichselian (MIS 4-3). Near complete sedimentary preservation occurred along the margins of the incised valley allowing the detailed reconstruction presented

Geological disposal of high-level radioactive waste and the role of rock engineering

International Nuclear Information System (INIS)

Sugihara, Kozo

2008-01-01

Japan Atomic Energy Agency (JAEA) and its predecessors have been conducting an extensive geoscientific research program since the 1970's in order to contribute to the formation of a firm scientific and technological basis for the geological disposal of high level radioactive waste in Japan. As a part of this program, in situ experiments have been performed at the Tono Mine in soft sedimentary rocks and at the Kamaishi Mine in hard crystalline rocks. An experiment on excavation disturbance has been one of these experiments and has revealed the extent and properties of the excavation disturbed zone (EDZ) and the applicability of available measurement methods. It is suggested that mechanical excavation and controlled excavation have reduced excavation damage of the rock mass around a drift, although some improvements in the currently available methods for measuring and simulating the EDZ are essential to understand excavation disturbance in more detail. JAEA is now promoting two underground research laboratory projects in Japan; the Mizunami Underground Research Laboratory (MIU) project for crystalline rocks and the Horonobe Underground Research Laboratory (Horonobe URL) project for sedimentary rocks. From a rock mechanical point of view, the major interest in these projects will be paid to failure phenomenon deep underground, rock stress estimation at larger scales and long-term physical stability of underground structure. These projects are open for international collaboration. (author)

Late Holocene sedimentary changes in floodplain and shelf environments of the Tagus River (Portugal)

NARCIS (Netherlands)

Vis, G.J.; Kasse, C.; Kroon, D.; Jung, S.J.A.; Zuur, H.; Prick, A.C.H.

2010-01-01

Sedimentary changes during the last ∼2500 years have been reconstructed from cored sedimentary records from the deltaic floodplain of the Lower Tagus Valley and the Tagus mudbelt on the continental shelf offshore Lisbon. We used a multi-proxy approach consisting of sedimentology, grainsize, pollen

Geologic studies on the Rio Una region (Iguape - Sao Paulo County), Brazil, for the construction of nuclear power plants

International Nuclear Information System (INIS)

Hassano, S.; Mueller, M.; Stein, J.H.

1984-01-01

The main objective of the project was the geological and seismological characterization of 230 Km 2 along the coastal region between the Barro Branco and Jureia massifs in order to pinpoint one or more local areas showing adequate geological, morphological and geotechnical conditions suitable for construction of nuclear power plants. Results of the investigations, as well as the methodology used for determination of main interesting areas are presented. The best areas for construction are believed to be situated along the coast where Precambrian basement rocks crop out close to the shoreline. The Tertiary-Quaternary sedimentary cover reaches a thickness of 50 or more meters and the character of the sediments does not allow direct emplacement of foundations for heavy-weight constructions. Historical analysis of seismic activity of the region, as well as the study of faults and fracture zones identified in the area demonstrate the absence of active faults such as defined by internationally accepted safety criteria. (Author) [pt

Cu-Ag Besshi type volcanogenic massive sulfide mineralization in the Late Cretaceous volcano- sedimentary sequence: the case of Garmabe Paein deposit, southeast of Shahrood

Directory of Open Access Journals (Sweden)

Majid Tashi

2017-07-01

Full Text Available Introduction Iran hosts numerous types of Volcanogenic massive sulfide (VMS deposits that occur within different tectonic assemblages and have formed at discrete time periods (Mousivand et al. 2008. The Sabzevar zone hosts several VMS deposits including the Nudeh Cu-Ag deposit (Maghfouri, 2012 and some deposits in the Kharturan area (Tashi et al., 2014, and the Kharturan area locates in the Sabzevar subzone of the Central East Iranian Microcontinent. The Sabzevar subzone mainly involves Mesozoic and Cenozoic rock unites. The Late Cretaceous ophiolite mellanges and volcano-sedimentary sequences have high extension in the Subzone. Based on Rossetti (Rossetti et al. 2010, the Cretaceous rock units were formed in a back-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate. The exposed rock units of the Kharturan area from bottom to top are dominated by Early Cretaceous, orbitolina-bearing massive limestone, dacitic-andesitic volcanics and related volcaniclastic rocks٫ chert and radiolarite and Late Cretaceous globotrunkana- bearing limestone, paleocene polygenic conglomerate consisting of the Cretaceous volcanics and limestone pebbles (equal to the Kerman conglomerate, and Pliocene weakly-cemented polygenic conglomerate horizon. The Garmabe Paein copper-silver deposit and the Asbkeshan deposit and a few occurrences, are located at 290 km southeast of Shahrood and they have occurred within the Upper Cretaceous volcano-sedimentary sequence in the Sabzevar subzone. The aim of this study is to discuss the genesis of the Garmabe Paein deposit based on geological, textural and structural, mineralogical and geochemical evidence. Materials and methods A field study and sampling was performed during the year 2013. During the field observations, 94 rock samples were collected from the study area, and 45 thin sections were prepared and studied using a polarizing microscope. Also, 5 samples for the XRD method, 21 samples for

Geology and geophysics of the Vila Nova Greenstone Belt, northeastern portion of the Amazonian Craton, Amapa, Brazil; Geologia e geofisica do greenstone belt Vila Nova, porcao NE do Craton Amazonico, Amapa, Brasil

Energy Technology Data Exchange (ETDEWEB)

Borghetti, Cristiano; Philipp, Ruy Paulo, E-mail: cborghetti@terra.com.br, E-mail: ruy.philipp@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre (Brazil)

2017-01-15

A few outcrops and strong weathering conditions prevail in the region of the Vila Nova Greenstone Belt in the southeastern Amapa (Brazil). This paper describes the use of airborne geophysical data for geological and structural analysis during geological mapping. This integration aims to improve the geological and tectonic understanding of this portion of the Amazonian Craton. The magnetometric and gamma-spectrometric qualitative interpretation of the images took place in a Geographic Information System (GIS) environment. Recognition of magnetometric and gamma-ray spectrometric units present in the study area was based on the hierarchical classification of polygons outlined by visual interpretation. The major geological domains and the structural patterns were defined by integration of geophysical data, geological mapping and petrographic analysis. The results allowed the recognition of Archean basement rocks composed of orthogneisses and granitoids of the Tumucumaque Complex, the metavolcano-sedimentary rocks of the Vila Nova Complex and Paleoproterozoic granite massifs. The integration of geophysical and field data resulted in the increase of the geological mapping definition, highlighting the importance of this methodology for recognition of complex structural and lithological fabrics in areas of difficult access and scarce fresh rock outcrops. (author)

Pore water colloid properties in argillaceous sedimentary rocks

Energy Technology Data Exchange (ETDEWEB)

Degueldre, Claude, E-mail: c.degueldre@lancaster.ac.uk [Engineering Department, University of Lancaster, LA1 4YW Lancaster (United Kingdom); ChiAM & Institute of Environment, University of Geneva, 1211 Genève 4, Swizerland (Switzerland); Earlier, NES, Paul Scherrer Institute, 5232 Villigen (Switzerland); Cloet, Veerle [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland)

2016-11-01

The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

Global gravity and the geodynamic model of the Earth

International Nuclear Information System (INIS)

Nedoma, J.

1988-01-01

Plate tectonic hypotheses require the formation of a new oceanic lithosphere at mid-oceanic ridges and imply the further modification and continued evolution towards the continental type of lithosphere in the regions of island arcs and orogenic belts. All these phenomena observed on the Earths's surface are results of all geodynamic processes passing through the Earth's interior. Since geodynamic processes change through the geological epochs, the gravity field also changes during the same geological periods. Thus, the paper is concerned with physical relationships between the global gravity field and the geodynamic processes as well as all geophysical fields affected by the geodynamic processes inside the Earth. The aim of this paper is to analyse the inner and outer gravity field of the Earth during the evolution of the Earth in the course of the geological epochs, and to build the generalized theory of the global gravity field of the Earth from the point of view of the global and local geodynamic processes taking place within the Earth's interior. (author)

Horonobe Underground Research Laboratory project. Current status on the surface-based investigation

International Nuclear Information System (INIS)

Hama, Katsuhiro; Ishii, Eiichi

2004-01-01

Aims of the Horonobe URL project are presenting concrete geological environment as an example of sedimentary formation and confirming reliability of technologies for geological disposal of High-Level Radioactive Waste (HLW) by applying them to actual geological condition of sedimentary formation. Social aim is providing opportunities for general public to experience the actual deep underground circumstance and R and D activities to be conducted there. (author)

How to find the sedimentary archive of fluvial pollution in a bedrock-confined river reach

Science.gov (United States)

Elznicova, Jitka; Matys Grygar, Tomas; Kiss, Timea; Lelkova, Tereza; Balogh, Marton; Sikora, Martin

2016-04-01

The Ohre River springs in the Eastern Germany and it is a tributary of the Labe (Elbe) River in Northwest Bohemia. The river received pollution from several sources during the last five centuries. Most of the pollution sources located along the upper and middle reaches, where the depositional and erosional pattern of the river is highly variable. The upper part of the catchment consists of mainly felsic rocks and the river has a broad floodplain. The middle reach and its right-bank tributaries are deeply incised into the Doupovske Hory Mts., which consists of mafic volcanic rocks; whereas the left-bank tributaries are incised into intrusive and metamorphic rocks of the Krusne Hory Mts. (Ore mountains) with several local ore mines (Ag, Pb and U) in particular in around Olovi and Jachymov. Due to the geologic and geomorphologic complexity, deposition of historical sediments in the middle reach has been spatially limited and uneven, and anomalous background concentrations of risk elements are expected. As a consequence, in the middle reach of the Ohre River it is difficult to find a useful sedimentary archive of historical pollution, though it is desired for two main reasons: (1) to decipher the undocumented and poorly described pollution history from the Krusne Hory Mts. and (2) to better understand the retention of pollutants in the transport zones of a confined river system. Based on historical maps we identified a side-bar (35x320 m) in the middle reach of the river near Straz on Ohre and aimed to describe its formation, its recent erosion/deposition history and to evaluate its sedimentary archive value. In the first half of the 19th century it was an island separated from the valley edge by a side channel. Since then there has been no apparent lateral accretion of the bar (its shape has not been changed), but the upstream part of the side channel aggraded by a sediment plug. We evaluated the current bar topography and geomorphology by a detailed field survey

Analysis of the technical potential for carbon capture and geological sequestration in the oil sector of Brazil; Analise do potencial tecnico do sequestro geologico de CO{sub 2} no setor petroleo no Brasil

Energy Technology Data Exchange (ETDEWEB)

Costa, Isabella Vaz Leal da

2009-02-15

This thesis focuses on the technologies related to CO{sub 2} capture and geological storage. The main objective of this study is to perform an analysis of the technical potential of geological sequestration of CO{sub 2} in the oil and gas sector in Brazil. Climate changes are directly related to emissions of greenhouse gases. Mainly, are related to increased carbon dioxide emissions due to the use of fossil fuels. To mitigate climate changes there are technologies that have the purpose of promoting the reduction of emissions of greenhouse gases such as the Geological Sequestration of CO{sub 2}. Thus, the study presents a description of the stages of the geological sequestration of CO{sub 2} and the state of the art of the technology in Brazil and worldwide. In addition, is presented the capacity for storage of the Brazilian sedimentary basins. Finally, this thesis analyzes the application of the described technologies in two stationary sources of great importance: refineries and oil and gas production fields. (author)

Evaluation of influence of splay fault growth on groundwater flow around geological disposal system

International Nuclear Information System (INIS)

Takai, Shizuka; Takeda, Seiji; Sakai, Ryutaro; Shimada, Taro; Munakata, Masahiro; Tanaka, Tadao

2017-01-01

In geological disposal, the direct effect of active faults on geological repositories is avoided at the stage of site characterization, however, uncertainty remains for the avoidance of faults derived from active faults, which are concealed deep under the ground and are difficult to detect by site investigation. In this research, the influence of the growth of undetected splay faults on a natural barrier in a geological disposal system due to the future action of faults was evaluated. We investigated examples of splay faults in Japan and set conditions for the growth of splay faults. Furthermore, we assumed a disposal site composed of sedimentary rock and made a hydrogeological model of the growth of splay faults. We carried out groundwater flow analyses, changing parameters such as the location and depth of the repository and the growth velocity of splay faults. We carried out groundwater flow analyses, changing parameters such as the location and depth of the repository and the growth velocity of splay faults. The results indicate that the main flow path from the repository is changed into an upward flow along the splay fault due to its growth and that the average velocity to the ground surface becomes one or two orders of magnitude higher than that before its growth. The results also suggest that splay fault growth leads to the possibility of the downward flow of oxidizing groundwater from the ground surface area. (author)

Modeling geomorphic changes in sedimentary rock areas. A case study in the Boso Peninsula area, Central Japan

International Nuclear Information System (INIS)

Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo; Sanga, Tomoji

2011-01-01

For the long-term safety of geological disposal of high-level radioactive wastes, evaluation of the radionuclide migration toward the human environment associated with groundwater flow is an issue of utmost importance. Therefore, we are carrying out a program for developing methods for assessing long-term groundwater flow in regional scales. As a part of the above program, we constructed models depicting the influences of geomorphological evolution on long-term groundwater flow. This was done by reconstructing the processes of river deepening with historical simulation of the profiles of four rivers in the Boso Peninsula. This area was selected because the sedimentary rocks are widely distributed with uncomplicated topography and geological structure which enabled the acquisition of a large amount of relevant geological information. The study resulted in the sum of erosion during the past 125,000 years which is the equivalent of one glacial to interglacial cycle. Consequently, the profiles of four rivers during the last glacial age to the present were successfully reconstructed using similar parameters. Also it was found that, in this area, the profiles were sculpted in accordance with the uplifting rates with very little influence of initial topography owing to the relatively soft and easily dissected characteristics of the geological units. However, detailed investigation revealed that the effects of geomorphological evolution differ between the rivers emptying into the inner bay and the rivers emptying into the open sea. In the case of the former two rivers, the river-bed elevation hardly changed during the 125,000 years and shows an extensive concave profile including the marine area. In the latter case, the elevation changed within the range of 20-30 m during the period and a convex profile appears in the marine area where the present water depth is over 30 m. Additionally the estimates of total amount of erosion during 125,000 years in the former group were

Development and management of the knowledge base for the geological disposal technology. Annual report 2006

International Nuclear Information System (INIS)

Umeda, Koji; Oyama, Takuya; Kurosawa, Hideki; Semba, Takeshi; Takeuchi, Shinji; Tajikara, Masayoshi; Tsuruta, Tadahiko; Yasue, Ken-ichi; Ohi, Takao; Oda, Chie; Kamei, Gento; Kobayashi, Yasushi; Sasaki, Yasuo; Sawada, Atsushi; Taniguchi, Naoki; Tanai, Kenji; Naito, Morimasa; Nakayama, Masashi; Kuno, Yoshio; Fujita, Tomoo; Honda, Akira; Mihara, Morihiro; Miyahara, Kaname; Osawa, Hideaki; Fujishima, Atsushi; Kuji, Masayoshi; Saito, Haruo; Sanada, Hiroyuki; Niizato, Tadafumi; Funaki, Hironori; Maekawa, Keisuke; Fujiwara, Kenso

2007-12-01

To increase technical reliability in geological disposal technology of high-level radioactive waste, JAEA have been conducting R and D activities in the fields in the repository engineering, performance assessment (PA) of the geological disposal system, and geoscientific study. In the field of R and D on the repository engineering, laboratory experimental studies at Tokai Research Center are carried out by engineering-scale and non-radiogenic experiments. The studies on performance assessment include more realistic model development with extensive computer analyses and acquisition of basic data concerning the chemical properties and migration behavior of radionuclides under geological disposal conditions. The information obtained from the Underground Research Laboratories (URLs) is used to provide a realistic condition of geological environments for these studies. The R and D studies are also carried out for TRU waste. A particular JAEA R and D activity is to promote the projects of two Underground Research Laboratories (URLs): one at Mizunami city, in crystalline rock and the other at Horonobe town, in sedimentary rock. In the present stage (2nd R and D phase) of the URL projects, the investigation are being carried out during the excavation of shafts and drifts. Data obtained from the investigations will serve to verify and refine the results from the surface-based investigations and characterize the evolution of the geological environment during drift excavation. The research on natural processes, such as fault and volcanic activities, is also conducted to provide better understanding of long-term stability on the geological environment. JAEA has initiated a project to develop the next generation of novel knowledge management system (KMS) to develop and manage the technical knowledge base for supporting implementers and regulators. This knowledge base includes all technical achievements by the JAEA as well as know-how and experience which have been accumulated

Excess europium content in Precambrian sedimentary rocks and continental evolution

Science.gov (United States)

Jakes, P.; Taylor, S. R.

1974-01-01

It is proposed that the europium excess in Precambrian sedimentary rocks, relative to those of younger age, is derived from volcanic rocks of ancient island arcs, which were the source materials for the sediments. Precambrian sedimentary rocks and present-day volcanic rocks of island arcs have similar REE patterns, total REE abundances, and excess Eu, relative to the North American shale composite. The present upper crustal REE pattern, as exemplified by that of sediments, is depleted in Eu, relative to chondrites. This depletion is considered to be a consequence of development of a granodioritic upper crust by partial melting in the lower crust, which selectively retains europium.

The Role of Geologic Mapping in NASA PDSI Planning

Science.gov (United States)

Williams, D. A.; Skinner, J. A.; Radebaugh, J.

2017-12-01

Geologic mapping is an investigative process designed to derive the geologic history of planetary objects at local, regional, hemispheric or global scales. Geologic maps are critical products that aid future exploration by robotic spacecraft or human missions, support resource exploration, and provide context for and help guide scientific discovery. Creation of these tools, however, can be challenging in that, relative to their terrestrial counterparts, non-terrestrial planetary geologic maps lack expansive field-based observations. They rely, instead, on integrating diverse data types wth a range of spatial scales and areal coverage. These facilitate establishment of geomorphic and geologic context but are generally limited with respect to identifying outcrop-scale textural details and resolving temporal and spatial changes in depositional environments. As a result, planetary maps should be prepared with clearly defined contact and unit descriptions as well as a range of potential interpretations. Today geologic maps can be made from images obtained during the traverses of the Mars rovers, and for every new planetary object visited by NASA orbital or flyby spacecraft (e.g., Vesta, Ceres, Titan, Enceladus, Pluto). As Solar System Exploration develops and as NASA prepares to send astronauts back to the Moon and on to Mars, the importance of geologic mapping will increase. In this presentation, we will discuss the past role of geologic mapping in NASA's planetary science activities and our thoughts on the role geologic mapping will have in exploration in the coming decades. Challenges that planetary mapping must address include, among others: 1) determine the geologic framework of all Solar System bodies through the systematic development of geologic maps at appropriate scales, 2) develop digital Geographic Information Systems (GIS)-based mapping techniques and standards to assist with communicating map information to the scientific community and public, 3) develop

Different controls on sedimentary organic carbon in the Bohai Sea: River mouth relocation, turbidity and eutrophication

Science.gov (United States)

Xu, Yunping; Zhou, Shangzhe; Hu, Limin; Wang, Yinghui; Xiao, Wenjie

2018-04-01

The extractable lipids and bulk organic geochemical parameters in three sediment cores (M-1, M-3 and M-7) from southern, central and northern Bohai Sea were analyzed in order to reconstruct environmental changes since 1900. The C/N ratio and multiple biomarkers (e.g., C27 + C29 + C31n-alkanes, C24 + C26 + C28n-alkanols, branched versus isoprenoid tetraether index) suggest more terrigenous organic carbon (OC) inputs in southern Bohai Sea. The abrupt changes of biomarker indicators in core M-1 are generally synchronous with the Yellow River mouth relocation events (e.g., 1964, 1976 and 1996), suggesting the distance to the river mouth being an important factor for sedimentary OC dispersal in the southern Bohai Sea. However, in cores M-3 and M-7, terrigenous biomarkers (i.e., BIT) show a long-term declining trend, consistent with a continuous reduction of the Yellow River sediment load, whereas marine biomarkers such as cholesterol, brassicasterol and dinosterol dramatically increased post-1980, apparently related to human-induced eutrophication in the Bohai Sea. Our study suggests different controlling factors on sedimentary OC distribution in the southern (high turbidity) and other parts (less turbidity) of the Bohai Sea, which should be considered for interpretation of paleoenvironments and biogeochemical processes in the river dominated margins that are hotspots of the global carbon cycling.

Imaging the Moho beneath Sedimentary Basins: A Comparative Study of Virtual Deep Seismic Sounding (VDSS) and P Wave Receiver Functions (PRF)

Science.gov (United States)

Liu, T.; Klemperer, S. L.; Yu, C.; Ning, J.

2017-12-01

In the past decades, P wave receiver functions (PRF) have been routinely used to image the Moho, although it is well known that PRFs are susceptible to contamination from sedimentary multiples. Recently, Virtual Deep Seismic Sounding (VDSS) emerged as a novel method to image the Moho. However, despite successful applications of VDSS on multiple datasets from different areas, how sedimentary basins affect the waveforms of post-critical SsPmp, the Moho reflection phase used in VDSS, is not widely understood. Here, motivated by a dataset collected in the Ordos plateau, which shows distinct effects of sedimentary basins on SsPmp and Pms waveforms, we use synthetic seismograms to study the effects of sedimentary basins on SsPmp and Pms, the phases used in VDSS and PRF respectively. The results show that when the sedimentary thickness is on the same order of magnitude as the dominant wavelength of the incident S wave, SsPmp amplitude decreases significantly with S velocity of the sedimentary layer, whereas increasing sedimentary thickness has little effect in SsPmp amplitude. Our explanation is that the low S velocity layer at the virtual source reduces the incident angle of S wave at the free surface, thus decreases the S-to-P reflection coefficient at the virtual source. In addition, transmission loss associated with the bottom of sedimentary basins also contributes to reducing SsPmp amplitude. This explains not only our observations from the Ordos plateau, but also observations from other areas where post-critical SsPmp is expected to be observable, but instead is too weak to be identified. As for Pms, we observe that increasing sedimentary thickness and decreasing sedimentary velocities both can cause interference between sedimentary multiples and Pms, rendering the Moho depths inferred from Pms arrival times unreliable. The reason is that although Pms amplitude does not vary with sedimentary thickness or velocities, as sedimentary velocities decrease and thickness

The Geomechanics of CO₂ Storage in Deep Sedimentary Formations

Energy Technology Data Exchange (ETDEWEB)

Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-01-12

This study provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO₂ storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO₂ repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO₂ storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large

A two-dimensional model of the passive coastal margin deep sedimentary carbon and methane cycles

Directory of Open Access Journals (Sweden)

D. E. Archer

2012-08-01

Full Text Available We present a new geologic-time and basin-spatial scale model of the continental margin methane cycle. The model, SpongeBOB, is used to simulate evolution of the carbon cycle in a passive sedimentary continental margin in response to changing oceanographic and geologic forcing over a time scale of 200 million years. The geochemistry of the sediment column is altered by the addition of vertical high-permeability channels intended to mimic the effects of heterogeneity in the real sediment column due to faults, and produces results consistent with measured pore-water tracers SO₄²⁻ and ¹²⁹I. Pore water dissolved inorganic carbon (DIC concentrations are consistent with chemical weathering (CaCO₃ formation from igneous rocks at depth within the sediment column. The carbon isotopic composition of the DIC is consistent with a methane production efficiency from particulate organic carbon (POC of 50%, which is somewhat lower than redox balance with the H / C of organic matter in the model. The hydrate inventory in the model is somewhat less sensitive to temperature than our previous results with a one-dimensional model, quite sensitive to reasonable changes in POC, and extremely sensitive to the ability of methane bubbles to rise within the sediment column, and how far gas-phase methane can get through the sediment column before it redissolves when it reaches undersaturated conditions. Hydrate formation is also sensitive to deep respiration of migrating petroleum. Other phenomena which we simulated had only a small impact on the hydrate inventory, including thermogenic methane production and production/decomposition of dissolved organic carbon.

Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system.

Science.gov (United States)

Choung, Sungwook; Zimmerman, Lisa R; Allen-King, Richelle M; Ligouis, Bertrand; Feenstra, Stanley

2014-10-15

This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc=0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen+black carbon was the dominant CM fraction extracted from the sediments and accounted for >60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that >80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthetic geology - Exploring the "what if?" in geology

Science.gov (United States)

Klump, J. F.; Robertson, J.

2015-12-01

The spatial and temporal extent of geological phenomena makes experiments in geology difficult to conduct, if not entirely impossible and collection of data is laborious and expensive - so expensive that most of the time we cannot test a hypothesis. The aim, in many cases, is to gather enough data to build a predictive geological model. Even in a mine, where data are abundant, a model remains incomplete because the information at the level of a blasting block is two orders of magnitude larger than the sample from a drill core, and we have to take measurement errors into account. So, what confidence can we have in a model based on sparse data, uncertainties and measurement error? Synthetic geology does not attempt to model the real world in terms of geological processes with all their uncertainties, rather it offers an artificial geological data source with fully known properties. On the basis of this artificial geology, we can simulate geological sampling by established or future technologies to study the resulting dataset. Conducting these experiments in silico removes the constraints of testing in the field or in production, and provides us with a known ground-truth against which the steps in a data analysis and integration workflow can be validated.Real-time simulation of data sources can be used to investigate crucial questions such as the potential information gain from future sensing capabilities, or from new sampling strategies, or the combination of both, and it enables us to test many "what if?" questions, both in geology and in data engineering. What would we be able to see if we could obtain data at higher resolution? How would real-time data analysis change sampling strategies? Does our data infrastructure handle many new real-time data streams? What feature engineering can be deducted for machine learning approaches? By providing a 'data sandbox' able to scale to realistic geological scenarios we hope to start answering some of these questions.

Tidal Simulations of an Incised-Valley Fluvial System with a Physics-Based Geologic Model

Science.gov (United States)

Ghayour, K.; Sun, T.

2012-12-01

Physics-based geologic modeling approaches use fluid flow in conjunction with sediment transport and deposition models to devise evolutionary geologic models that focus on underlying physical processes and attempt to resolve them at pertinent spatial and temporal scales. Physics-based models are particularly useful when the evolution of a depositional system is driven by the interplay of autogenic processes and their response to allogenic controls. This interplay can potentially create complex reservoir architectures with high permeability sedimentary bodies bounded by a hierarchy of shales that can effectively impede flow in the subsurface. The complex stratigraphy of tide-influenced fluvial systems is an example of such co-existing and interacting environments of deposition. The focus of this talk is a novel formulation of boundary conditions for hydrodynamics-driven models of sedimentary systems. In tidal simulations, a time-accurate boundary treatment is essential for proper imposition of tidal forcing and fluvial inlet conditions where the flow may be reversed at times within a tidal cycle. As such, the boundary treatment at the inlet has to accommodate for a smooth transition from inflow to outflow and vice-versa without creating numerical artifacts. Our numerical experimentations showed that boundary condition treatments based on a local (frozen) one-dimensional approach along the boundary normal which does not account for the variation of flow quantities in the tangential direction often lead to unsatisfactory results corrupted by numerical artifacts. In this talk, we propose a new boundary treatment that retains all spatial and temporal terms in the model and as such is capable to account for nonlinearities and sharp variations of model variables near boundaries. The proposed approach borrows heavily from the idea set forth by J. Sesterhenn1 for compressible Navier-Stokes equations. The methodology is successfully applied to a tide-influenced incised

A petrological study of Paleoarchean rocks of the Onverwacht Group: New insights into the geologic evolution of the Barberton Greenstone Belt, South Africa

Science.gov (United States)

Grosch, E. G.; Mcloughlin, N.; Abu-Alam, T. S.; Vidal, O.

2012-12-01

This study presents a multi-disciplinary petrological approach applied to surface samples and a total of 800 m of scientific drill core that furthers our understanding of the geologic evolution of the ca. 3.5 to 3.2 Ga Onverwacht Group of the Barberton greenstone belt (BGB), South Africa. Detrital zircon grains in coarse (diamictite) to fine-grained clastic sedimentary rocks of the Noisy formation (drill core KD2a) that unconformably overlies the volcanic ca. 3472 Ma Hooggenoeg Formation, are investigated by laser ablation LA-ICP-MS to constrain their 207Pb/206Pb ages for depositional age and provenance. A wide range in 207Pb/206Pb ages between ca. 3600 and 3430 Ma is reported, corresponding to surrounding TTG plutons and the ca.3667-3223 Ma Ancient Gneiss Complex. The youngest detrital zircon grain identified has an age of 3432 ± 10 Ma. Given the short time interval for a major change in geologic environment between ca. 3472 Ma and ca. 3432 Ma, it is argued here, that the Noisy formation is the earliest tectonic basin in the BGB, which developed during major tectonic uplift at ca. 3432 Ma. In the overlying ca. 3334 Ma Kromberg type-section, application of a chlorite thermodynamic multi-equilibrium calculation, dioctahedral mica hydration-temperature curve and pseudosection modelling, indicates a wide range in metamorphic conditions from sub-greenschist to the uppermost greenschist facies across the Kromberg type-section. A central mylonitic fuchsite-bearing zone, referred to as the Kromberg Section Mylonites, records at least two metamorphic events: a high-T, low-P (420 ± 30oC, sedimentary sequence contains detrital and diagenetic pyrites with a significant variation in Δ33S of -0.62 to +1.4‰ and δ34SCDT between -7.00 and +12.6‰ in the upper turbidite unit, to more narrow isotopic ranges with magmatic-atmospheric values in the underlying polymictitic diamictite. A sedimentary quartz-pyrite vein in the diamictite records the largest range and most negative

Microbial mat-induced sedimentary structures in siliciclastic sediments

Indian Academy of Sciences (India)

This paper addresses macroscopic signatures of microbial mat-related structures within the. 1.6Ga-old Chorhat Sandstone ... Sandstone differentiated in facies superposed one over the other and their respective structural assemblages (b). may be ..... within the classification of primary sedimentary struc- tures; J. Sed. Res.

GIS-technologies as a mechanism to study geological structures

Science.gov (United States)

Sharapatov, Abish

2014-05-01

Earth scientists are odd, thus, solving only local tasks); - Development of specialized GIS-technology that ensures creating multi-parameter models, completing multi-criteria optimisation tasks, and issues of geological profile forecasts using miscellaneous data; - Application of the modern approach to the geological, petrological and genetic modeling of the targets in the geological zone under survey; determination of the structural and tectonic position of the Valerianovskaya SFZ and its relations to the mineralization; - A possibility to apply the GIS created for the region as a desk (local) system integrated to the regional or national bank of geospatial information with a corporate access via local and global networks.

Exploring Global Change In Place-Based Case Studies

Science.gov (United States)

Moosavi, S. C.

2011-12-01

The complexity of global climate change makes the subject challenging for the average student, particularly given the nuanced feedbacks and exceptions to the general "warming" or "drying" trend that may be experienced at the local and regional level at which most people experience geologic processes. Geoscience educators can reduce these barriers and draw in student learners by adopting a place-based approach to teaching and researching geologic principles that relate to global change. Assisting students in recognizing and understanding the geologic environment in which they live and study has the side benefit of making the potential effect of climate change tangible. This presentation will review several approaches for using place-based case studies to explore global climate change issues in large lecture, small seminar, field research and service learning environments. The special place project used in large introductory physical geology courses requires each student to select a place familiar and unique to them for an in depth study of the common course content as the semester progresses. Students are specifically tasked with identifying how their site came to be, the geologic processes that act upon it today, how the site may have been different during the last glacial advance and how global climate change (specifically warming of 3OC over 50 years) might impact the site. The concept that change has occurred at the student's site in the past, even far from glacial environments, opens students to the scale of potential anthropogenic climate change. A freshman seminar Global Warming & Climate Change - Service in Preparation for Climate Change: The Second Battle of New Orleans focused on the environmental threats to New Orleans and southeastern Louisiana resulting from regional land use decisions in the centuries before Hurricane Katrina, and the threat that global change relating to sea level rise, acceleration of the hydrologic cycle and intensification of

The use of Nd isotopes to establish sedimentary provenance at inverted passive margins: The case of Andrelandia depositional cycle at the Riberia belt, Brazil

International Nuclear Information System (INIS)

Ragatky, D.; Tupinamba, M.; Duarte, B.P

2001-01-01

The Ribeira Belt (Almeida et al., 1973), in southeastern Brazil, is a Brasiliano/Pan-African belt that resulted from the agglutination of the Gondwana Supercontinent (750-500 Ma). The tectonic organization at its central segment can be defined by several tectono-stratigraphic domains (Heilbron et al., 1998, 2000). In general terms, each tectonic domain comprises: a) pre-1.8 Ga basement rocks; b) post-1.8 Ga metasedimentary cover including metabasic rocks of continental to MORB geochemical affinity; and c) Brasiliano-Pan African granitoids. U/Pb ages for zircon, titanite and monazite of both the pre-1.8 Ga basement and Brasiliano granitoids (Machado et al., 1996) reveal that basement gneisses were generated during the Transamazonian Orogeny, about 2.1 Ga. Peak metamorphic conditions (M1) of the Brasiliano Collage at the central Ribeira belt were reached at 590 - 565 Ma, with a second metamorphic event (M2) at 535 - 520 Ma (Machado et al., 1996). Our research area is located at the transition between the foreland and the hinterland of the Ribeira belt: the Occidental terrane. It represents a reworked margin of the Sao Francisco Craton, formerly known as a proterozoic tectonic plate. It is composed by two crustal scale thrust sheets (Andrelandia and Juiz de Fora domains) tangentially transported towards the foreland of Sao Francisco Craton. Despite the well-determined ages of the Transamazonic basement and Brasiliano granitic rocks (Machado et al. 1996), the sedimentary source of the siliciclastic cover at the Occidental terrane remains poorly known. In this case, the use of Nd isotopic system, due to its relative immobility, is an important additional tool of investigation in geological correlation between basement source areas and sedimentary cover. The siliciclastic sedimentary and metasedimentary rocks are formed by detritus of pre-existing crustal rocks and they could be formed by more than one source. Then, depleted mantle Nd model ages (T DM ) for sediments

A high resolution global scale groundwater model

Science.gov (United States)

de Graaf, Inge; Sutanudjaja, Edwin; van Beek, Rens; Bierkens, Marc

2014-05-01

As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater storage provides a large natural buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). With this global groundwater model we eventually intend to simulate the changes in the groundwater system over time that result from variations in recharge and abstraction. Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013), combined with our estimate of aquifer thickness for sedimentary basins. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. Based on our sensitivity analysis, in which we run the model with various hydrogeological parameter settings, we observed that most variance in groundwater

Titan's methane cycle and its effect on surface geology

Science.gov (United States)

Lopes, R. M.; Peckyno, R. S.; Le Gall, A. A.; Wye, L.; Stofan, E. R.; Radebaugh, J.; Hayes, A. G.; Aharonson, O.; Wall, S. D.; Janssen, M. A.; Cassini RADAR Team

2010-12-01

Titan’s surface geology reflects surface-atmospheric interaction in ways similar to Earth’s. The methane cycle on Titan is a major contributor to the formation of surface features such as lakes, seas, rivers, and dunes. We used data from Cassini RADAR to map the distribution and relative ages of terrains that allow us to determine the geological processes that have shaped Titan’s surface. These SAR swaths (up to Titan flyby T64) cover about ~45% percent of the surface, at a spatial resolution ranging from 350 m to about >2 km. The data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution and significance of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth. In this paper, we update the geologic unit map that used flybys up to T30 (Lopes et al., 2010, Icarus, 205, 540-558), representing ~20% of the surface. We find that the overall correlations found previously still hold given more than double the areal coverage. In terms of global areal distribution, both dunes and mountainous terrains (including Xanadu) cover more area (respectively 9.2% and 14.6% of the observed area) than other identified geologic units. In terms of latitudinal distribution, dunes and hummocky, mountainous terrains are located mostly at low latitudes (less than 30 degrees), with no dunes being present above 60 degrees. Channels formed by fluvial activity are present at all latitudes, but lakes filled with liquid are found at high latitudes only (above 60 degrees). Impact structures are mostly located at low latitudes, with no confidently identified craters above 60 degrees latitude, possibly indicating that more resurfacing has occurred at higher latitudes. Putative cryovolcanic features, consisting mostly of flows, are not ubiquitous and are mostly located in the areas surrounding Xanadu. We examine temporal relationships between

Modern sedimentary processes along the Doce river adjacent continental shelf

Directory of Open Access Journals (Sweden)

Valéria da Silva Quaresma

Full Text Available In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.

Reconnaissance geologic map of the Dubakella Mountain 15 quadrangle, Trinity, Shasta, and Tehama Counties, California

Science.gov (United States)

Irwin, William P.; Yule, J. Douglas; Court, Bradford L.; Snoke, Arthur W.; Stern, Laura A.; Copeland, William B.

2011-01-01

The Dubakella Mountain 15' quadrangle is located just south of the Hayfork quadrangle and just east of the Pickett Peak quadrangle. It spans a sequence of four northwest-trending tectonostratigraphic terranes of the Klamath Mountains geologic province that includes, from east to west, the Eastern Hayfork, Western Hayfork, Rattlesnake Creek, and Western Jurassic terranes, as well as, in the southwest corner of the quadrangle, part of a fifth terrane, the Pickett Peak terrane of the Coast Ranges geologic province. The Eastern Hayfork terrane is a broken formation and melange of volcanic and sedimentary rocks that include blocks of limestone and chert. The limestone contains late Permian microfossils of Tethyan faunal affinity. The chert contains radiolarians of Mesozoic age, mostly Triassic, but none clearly Jurassic. The Western Hayfork terrane is an andesitic volcanic arc that consists mainly of agglomerate, tuff, argillite, and chert, and includes the Wildwood pluton. That pluton is related to the Middle Jurassic (about 170 Ma) Ironside Mountain batholith that is widely exposed farther north beyond the Dubakella Mountain quadrangle. The Rattlesnake Creek terrane is a highly disrupted ophiolitic melange of probable Late Triassic or Early Jurassic age. Although mainly ophiolitic, the melange includes blocks of plutonic rocks (about 200 Ma) of uncertain genetic relation. Some scattered areas of well-bedded mildly slaty detrital rocks of the melange appear similar to Galice Formation (unit Jg) and may be inliers of the nearby Western Jurassic terrane. The Western Jurassic terrane consists mainly of slaty to phyllitic argillite, graywacke, and stretched-pebble conglomerate and is correlative with the Late Jurassic Galice Formation of southwestern Oregon. The Pickett Peak terrane, the most westerly of the succession of terranes of the Dubakella Mountain quadrangle, is mostly fine-grained schist that includes the blueschist facies mineral lawsonite and is of Early

Bringing the Global Scale to Education in Natural Resources Management

Science.gov (United States)

Turner, D. P.

2017-12-01

Given the ominous trajectory of rapid global environmental change, environmental managers must grapple with global scale structures, processes, and concepts. The concept of the Anthropocene Epoch, albeit contested, is highly integrative across disciplines and temporal scales, and thus potentially helpful in the context of educating environmental managers. It can be framed temporally in terms of the geologic history of the global environment, the initiation and acceleration of anthropogenic impacts on the environment, and a future global environment that is highly dependent on human decisions. A key lesson from Earth's pre-human geologic history is that global climate has generally been linked to greenhouse gas concentrations, and many mass extinction events were associated with high greenhouse gas concentrations. The pervasive impacts of the contemporary technosphere on the biosphere point especially to the need to conserve biosphere capital. Scenarios of Earth's future environment, based on Earth system models, suggest that business-as-usual technologies and economic practices will set the stage for a biophysical environment that is hostile (if not inimical) to a high technology global civilization. These lessons can inform and inspire sub-global management efforts to mitigate and adapt to global environmental change.

Geochemical elements mobility during the history of a paleo-Proterozoic clastic sedimentary basin, the Athabasca Basin (Saskatchewan, Canada)

International Nuclear Information System (INIS)

Kister, P.

2003-10-01

In order to understand the mechanisms of migration and deposition of ore elements, it is essential to determine the timing, source, and destination of the geochemical element mass transfers and/or transportation on a scale encompassing the great sedimentary. The purpose of this study was to trace and to date the element migrations that occurred during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin, which hosts the world's largest and richest uranium deposits. As this geological environment was proved to be efficient to preserve high grade ore deposits for over more than one billion years, it provides an opportunity to study the mobility of some elements in a context that shows analogies with deep geological nuclear waste disposals. The natural analogies of interest include (i) uranium oxide and spent nuclear fuel; (ii) clay alteration halo and near field barrier, (iii) Athabasca sandstone cover and far-field barrier. Five research axis: (1) 3D modelling of the distribution of the main minerals and of some trace elements (U, Pb, Zr, Th, REE, Y, Rb, Sr) on a basin-wide scale and in the U mineralized zones, using the Gocad software. The models have been compared with detailed mineralogical studies performed on selected samples. (2) Pb-Pb and Rb-Sr systematics by TIMS (3) Mass balance calculation of the average Pb/U ratio at the scale of the deposit to evaluate whether the present day amount of radiogenic lead is sufficient to explain a U deposition in one or several episodes (geostatistical tools on Gocad) (4) Thermodynamic modelling of the mineralogical evolution of the Athabasca basin, considering the main mineral present in the sandstone (Phreeqc and Supcrt softwares) (5) U-Pb geochronology of uranium oxides using a 3 step approach: (i) optical and scanning electron microscopy; (ii) electron microprobe; (iii) ion microprobe (SIMS). The purpose was to study the long term stability of the uranium oxides and to characterise the

Geology and environments of subglacial Lake Vostok.

Science.gov (United States)

Leitchenkov, German L; Antonov, Anton V; Luneov, Pavel I; Lipenkov, Vladimir Ya

2016-01-28

The reconstruction of the geological (tectonic) structure and environments of subglacial Lake Vostok is based on geophysical surveys and the study of mineral particles found in cores of accreted ice and frozen lake water (sampled after the lake was unsealed). Seismic reflection and refraction investigations conducted in the southern part of Lake Vostok show very thin (200-300 m) sedimentary cover overlying a crystalline basement. Most of this thin veneer is thought to have been deposited during temperate-glacial conditions in Oligocene to Middle Miocene time (ca 34-14 Ma). The composition of the lake-bottom sediments can be deduced from mineral inclusions found in cores of accreted ice. Inclusions are represented by soft aggregates consisting mainly of clay-mica minerals and micrometre-sized quartz grains. Some of these inclusions contain subangular to semi-rounded rock clasts (siltstones and sandstones) ranging from 0.3 to 8 mm in size. In total, 31 zircon grains have been identified in two rock clasts and dated using SHRIMP-II. The ages of the studied zircons range from 0.6 to 2.0 Ga with two distinct clusters between 0.8 and 1.15 Ga and between 1.6 and 1.8 Ga. Rock clasts obviously came from the western lake shore, which is thus composed of terrigenous strata with an age of not older than 600 Ma. The sedimentary nature of the western lake shore is also confirmed by seismic refraction data showing seismic velocities there of 5.4-5.5 km s(-1) at the bedrock surface. After Lake Vostok was unsealed, its water (frozen and sampled next season) was also studied with scanning electron microscopy and X-ray microprobe analysis. This study showed the existence of calcium carbonate and silica microparticles (10-20 μm across) in frozen water. © 2015 The Author(s).