Influence of Sediment Type and Depositional Processes on Stratal Patterns in the Permian Basin-Margin Lamar Limestone, McKittrick Canyon, Texas

1993 ◽  
pp. 133-156
Keyword(s):  
Sediment Type ◽  
Permian Basin ◽  
Depositional Processes ◽  
Basin Margin

Depositional conditions at the Aptian Pre-salt margins: evidence from quantitative petrography and textural analysis of the Mucuri Member, Espírito Santo Basin, Brazil

2021 ◽  
pp. petgeo2020-112
Author(s):  
G. Pantopoulos ◽  
G. K. L. Orita ◽  
G. Armelenti ◽  
C. E. Althaus ◽  
J. Kuchle ◽  
...  
Keyword(s):  
Grain Size ◽  
Settling Velocity ◽  
Textural Analysis ◽  
Coastal Sediments ◽  
Coarse Grained ◽  
Sediment Type ◽  
Espírito Santo ◽  
Depositional Processes ◽  
Depositional Settings ◽  
Espirito Santo

Aptian siliciclastic onshore deposits of the Mucuri Member are important reservoirs in the Espírito Santo Basin (eastern Brazil). A detailed quantitative petrographic and textural analysis of well core samples was performed in order to unravel their depositional processes and conditions, in relation to previously proposed depositional models. The results allowed the differentiation between two groups of sandstone samples, characterized by different textural characteristics associated to different depositional processes and environments within the Mucuri depositional system. Fluvial sandstones are represented by medium- to coarse-grained, poorly-sorted arkoses, rich in plutonic rock fragments and feldspar grains, mainly transported by traction. Coastal-lacustrine sandstones correspond to very fine- to fine-grained, moderately-sorted micaceous arkoses, mainly transported in suspension. The application of a discriminant function based on grain size parameters validated previously proposed depositional settings for the studied sample groups. The combination of grain size and shape data revealed differences in hydraulic equivalence and shape between grains from different depositional settings. In terms of hydraulic equivalence, micas in the fluvial sediments present lower settling velocity values, in contrast with the relatively large mica grains in the coastal sediments, which are hydraulically equivalent with the associated quartz and feldspar grains. The results of this study provide key information regarding depositional conditions (transportation mechanisms, grain settling velocity and mineral hydraulic fractionation) at the margins of the Aptian Pre-salt system, which can constrain the hydrological conditions and the sediment type available for distal lacustrine areas.

scholarly journals Submarine mass failures as tsunami sources: their climate control

2010 ◽  
Vol 368 (1919) ◽  
pp. 2417-2434 ◽  
Author(s):  
D. R. Tappin
Keyword(s):  
Submarine Canyon ◽  
Coarse Grained ◽  
Sediment Type ◽  
Potential Hazard ◽  
Convergent Margins ◽  
Climate Control ◽  
River Deltas ◽  
Storm Waves ◽  
Depositional Processes ◽  
Climate Controls

Recent research on submarine mass failures (SMFs) shows that they are a source of hazardous tsunamis, with the tsunami magnitude mainly dependent on water depth of failure, SMF volume and failure mechanism, cohesive slump or fragmental landslide. A major control on the mechanism of SMFs is the sediment type, together with its post-depositional alteration. The type of sediment, fine- or coarse-grained, its rate of deposition together with post-depositional processes may all be influenced by climate. Post-depositional processes, termed sediment ‘preconditioning’, are known to promote instability and failure. Climate may also control the triggering of SMFs, for example through earthquake loading or cyclic loading from storm waves or tides. Instantaneous triggering by other mechanisms such as fluid overpressuring and hydrate instability is controversial, but is here considered unlikely. However, these mechanisms are known to promote sediment instability. SMFs occur in numerous environments, including the open continental shelf, submarine canyon/fan systems, fjords, active river deltas and convergent margins. In all these environments there is a latitudinal variation in the scale of SMFs. The database is limited, but the greatest climate influence appears to be in high latitudes where glacial/interglacial cyclicity has considerable control on sedimentation, preconditioning and triggering. Consideration of the different types of SMFs in the context of their climate controls provides additional insight into their potential hazard in sourcing tsunamis. For example, in the Atlantic, where SMFs are common, the tsunami hazard under the present-day climate may not be as great as their common occurrence suggests.

A correlation of CL emissions from Penrith sandstone with elemental distributions obtained by simultaneous SEM-CL and EDS analysis

1995 ◽  
Vol 53 ◽  
pp. 392-393
Author(s):  
Paul J. Wright
Keyword(s):  
Optical Microscope ◽  
Electron Gun ◽  
High Electron ◽  
Collection System ◽  
Electron Hole ◽  
Depositional Processes ◽  
Eds Analysis ◽  
Distribution Mapping ◽  
Backscattered Electron ◽  
Electron Imaging

Most industrial and academic geologists are familiar with the beautiful red and orange cathodoluminescence colours produced by carbonate minerals in an optical microscope with a cold cathode electron gun attached. The cement stratigraphies interpreted from colour photographs have been widely used to determine the post depositional processes which have modified sedimentary rock textures.However to study quartzose materials high electron densities and kV's are necessary to stimulate sufficient emission. A scanning electron microscope with an optical collection system and monochromator provides an adequate tool and gives the advantage of providing secondary and backscattered electron imaging as well as elemental analysis and distribution mapping via standard EDS/WDS facilities.It has been known that the incorporation of many elements modify the characteristics of the CL emissions from geological materials. They do this by taking up positions between the valence and conduction band thus providing sites to assist in the recombination of electron hole pairs.

Assessment of undiscovered continuous oil resources in the Wolfcamp shale of the Midland Basin, Permian Basin Province, Texas, 2016

Fact Sheet ◽  
2016 ◽  
Author(s):  
Stephanie B. Gaswirth ◽  
Kristen R. Marra ◽  
Paul G. Lillis ◽  
Tracey J. Mercier ◽  
Heidi M. Leathers-Miller ◽  
...  
Keyword(s):  
Permian Basin ◽  
Midland Basin ◽  
Oil Resources
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