Geology of the Sirius Group at Mount Feather and Table Mountain, South Victoria Land, Antarctica

<p>The Sirius Group comprises of wet based glacial and related deposits found at high elevations throughout the Transantarctic Mountains. The discovery of marine Pliocene diatoms from within glacial till by Harwood (1983) led Webb et al. (1984) to propose that they were sourced from diatom bearing sediment eroded by glaciers from middle Pliocene marine basins inland of the Transantarctic Mountains. Others consider that temperatures during middle Pliocene times were not high enough to melt back the Antarctic ice sheet and expose these inland basins. They support the long held view of a stable Antarctic ice sheet since middle Miocene times, and insist that the Sirius Group is much older, explaining the diatoms as wind blown. This study was undertaken in order to determine whether the diatoms were incorporated into Sirius Group tills during or after their deposition. Sites were sampled at Mount Feather and Table Mountain in South Victoria Land. The distribution of diatoms through the upper 37 cm of the till were documented. Samples were also taken in snow and from other non Sirius Group surfaces (regolith) for comparison purposes. The geomorphic setting of the Sirius Group tills at Mt. Feather and Table Mountain suggests that their deposition predated the deep valleys that now run through the Transantarctic Mountains. Diatom abundances from within the tills are low (averaging about 1 diatom diatom per gram) and highly variable from site to site. Initially 184 diatoms were recovered from 10 samples at Mt. Feather and less than 7 diatoms were found from 4 samples of till at Table Mountain. At Mount Feather diatoms are concentrated in the surface few centimetres of the till and numbers generally decrease with depth. The pore size within the tills is highly variable but is on average ten times the size of the average diatom (10-15 microns) from within the deposits, allowing at least some diatoms to work their way into the tills from the surface. Diatoms from the snow and regolith from other rock surfaces have a similar diatom assemblage to the Sirius tills, containing many of the same common forms. Some non Sirius Group regolith samples have much larger concentrations of diatoms suggesting they have a much better trapping ability than the Sirius Group tills. These data indicate that most diatoms from the Sirius Group tills have been introduced from the atmosphere and have worked their way into the till. Thus the Sirius diatoms record not Pliocene marine basins of the Antarctic interior and subsequent extensive over riding glaciation, but the atmospheric transport and collection of both modern and ancient diatom bearing dust from within and beyond the continent. The Sirius Group tills do however have a phytolith (siliceous clasts from the cells of plant tissue) flora of glaciogenic origin, indicated by the lack of a vertical trend in abundance and very low levels of phytoliths in nearby snow and regolith samples.</p>

Geology of the Sirius Group at Mount Feather and Table Mountain, South Victoria Land, Antarctica

<p>The Sirius Group comprises of wet based glacial and related deposits found at high elevations throughout the Transantarctic Mountains. The discovery of marine Pliocene diatoms from within glacial till by Harwood (1983) led Webb et al. (1984) to propose that they were sourced from diatom bearing sediment eroded by glaciers from middle Pliocene marine basins inland of the Transantarctic Mountains. Others consider that temperatures during middle Pliocene times were not high enough to melt back the Antarctic ice sheet and expose these inland basins. They support the long held view of a stable Antarctic ice sheet since middle Miocene times, and insist that the Sirius Group is much older, explaining the diatoms as wind blown. This study was undertaken in order to determine whether the diatoms were incorporated into Sirius Group tills during or after their deposition. Sites were sampled at Mount Feather and Table Mountain in South Victoria Land. The distribution of diatoms through the upper 37 cm of the till were documented. Samples were also taken in snow and from other non Sirius Group surfaces (regolith) for comparison purposes. The geomorphic setting of the Sirius Group tills at Mt. Feather and Table Mountain suggests that their deposition predated the deep valleys that now run through the Transantarctic Mountains. Diatom abundances from within the tills are low (averaging about 1 diatom diatom per gram) and highly variable from site to site. Initially 184 diatoms were recovered from 10 samples at Mt. Feather and less than 7 diatoms were found from 4 samples of till at Table Mountain. At Mount Feather diatoms are concentrated in the surface few centimetres of the till and numbers generally decrease with depth. The pore size within the tills is highly variable but is on average ten times the size of the average diatom (10-15 microns) from within the deposits, allowing at least some diatoms to work their way into the tills from the surface. Diatoms from the snow and regolith from other rock surfaces have a similar diatom assemblage to the Sirius tills, containing many of the same common forms. Some non Sirius Group regolith samples have much larger concentrations of diatoms suggesting they have a much better trapping ability than the Sirius Group tills. These data indicate that most diatoms from the Sirius Group tills have been introduced from the atmosphere and have worked their way into the till. Thus the Sirius diatoms record not Pliocene marine basins of the Antarctic interior and subsequent extensive over riding glaciation, but the atmospheric transport and collection of both modern and ancient diatom bearing dust from within and beyond the continent. The Sirius Group tills do however have a phytolith (siliceous clasts from the cells of plant tissue) flora of glaciogenic origin, indicated by the lack of a vertical trend in abundance and very low levels of phytoliths in nearby snow and regolith samples.</p>

Seismic Stratigraphic Analysis and Hydrocarbon Potential of Miocene-Quaternary Deposits in the Western Nile Delta Basin

This study focuses on the subsurface Miocene-Pleistocene sedimentary sequence of the Western Delta of Deep-Sea field. Analysis of seismic, based on obtainable well data, and seismic data, allows us to divide the studied successions into two mega sequences: Pre and Post Messinian complexes resulting in transgressive-regressive sedimentation cycles of sea level during the evolution of the Miocene-Pleistocene subsurface sedimentary sequence. The Relative level of the sea was extremely falling in the time of the Messinian period, although it was largely rising at the time of the lower to Middle Pliocene. Pre-Messinian complex encompasses the Miocene strata, while the Post-Messinian complex consists of a thickness pattern of deposits in the time of Pliocene to Pleistocene and ended up with Holocene. The comprehensive study presented here divides these complexes into several orders of sea-level cycles. Pre and Post-Messinian complexes are consisting of several third-order cycles, which is called a depositional sequence, hence the thickness pattern starts from Sidi Salem Formation and ends up with Mit Ghamr Formation (Pleistocene). The interpreted anticline represents a characteristic overlap that can create an appropriate structural trap for hydrocarbons in the sandy intermission of the formations of the Western Deep-Sea Delta field such as Kafr El Sheik siliceous clastic. Besides, the recognized individual and various hidden routes, such as channel and sub-channel in the Pre-Messinian complex are approved for additional inspection to discover hydrocarbons.

Integrated Rock and Fluid Workflow to Optimize Geomodeling and History Matching

Optimized geomodeling and history matching of production data is presented by utilizing an integrated rock and fluid workflow. Facies identification is performed by use of image logs and other geological information. In addition, image logs are used to help define structural geodynamic processes that occurred in the reservoir. Methods of reservoir fluid geodynamics are used to assess the extent of fluid compositional equilibrium, especially the asphaltenes, and thereby the extent of connectivity in these facies. Geochemical determinations are shown to be consistent with measurements of compositional thermodynamic equilibrium. The ability to develop the geo-scenario of the reservoir, the coherent evolution of rock and contained fluids in the reservoir over geologic time, improves the robustness of the geomodel. In particular, the sequence of oil charge, compositional equilibrium, fault block throw, and primary biogenic gas charge are established in this middle Pliocene reservoir with implications for production, field extension,and local basin exploration. History matching of production data prove the accuracy of the geomodel; nevertheless, refinements to the geomodel and improved history matching were obtained by expanded deterministic property estimation from wireline log and other data. Theearly connection of fluid data, both thermodynamic and geochemical, with relevant facies andtheir properties determination enables a more facile method to incorporate this data into the geomodel. Logging data from future wells in the field can be imported into the geomodel allowingdeterministic optimization of this model long after production has commenced. While each reservoir is unique with its own idiosyncrasies, the workflow presented here is generally applicable to all reservoirs and always improves reservoir understanding.

Chemostratigraphic and Textural Indicators of Nucleation and Growth of Polymetallic Nodules from the Clarion-Clipperton Fracture Zone (IOM Claim Area)

The detailed mineralogical and microgeochemical characteristics of polymetallic nodules collected from the Interoceanmetal Joint Organization (IOM) claim area, Eastern Clarion-Clipperton Fracture Zone (CCFZ, Eastern Pacific) were described in this study. The obtained data were applied for the delimitation of nodule growth generations and estimation of the growth ratios (back-stripping using the Co-chronometer method). The applied methods included bulk X-ray powder diffraction (XRD) and electron probe microanalysis (EPMA), providing information about Mn-Fe minerals and clays composing nodules, as well as the geochemical zonation of the growth generations. The analyzed nodules were mostly diagenetic (Mn/Fe > 5), with less influence on the hydrogenous processes, dominated by the presence of 10-Å phyllomanganates represented by todorokite/buserite, additionally mixed with birnessite and vernadite. The specific lithotype (intranodulith), being an integral part of polymetallic nodules, developed as a result of the secondary diagenetic processes of lithification and the cementation of Fe-rich clays (potentially nontronite and Fe-rich smectite), barite, zeolites (Na-phillipsite), bioapatite, biogenic remnants, and detrital material, occurs in holes, microcaverns, and open fractures in between ore colloforms. The contents of ∑(Ni, Cu, and Co) varied from 1.54 to 3.06 wt %. Several remnants of siliceous microorganisms (radiolarians and diatoms) were found to form pseudomorphs. The applied Co-chronometer method indicated that the nodules’ age is mainly Middle Pliocene to Middle Pleistocene, and the growth rates are typical of diagenetic and mixed hydrogenetic–diagenetic (HD) processes. Additionally, few nodules showed suboxic conditions of nucleation. Growth processes in the eastern part of the CCFZ deposit might have been induced with the Plio-Pleistocene changes in the paleooceanographic conditions related to the deglaciation of the Northern Hemisphere.

Plio–Quaternary Structural Evolution of the Outer Sector of the Marche Apennines South of the Conero Promontory, Italy

Some new results and preliminary remarks about the Plio–Quaternary structural and evolutionary characteristics of the outer Marche Apennines south in the Conero promontory are presented in this study. The present analysis is based on several subsurface seismic reflection profiles and well data, kindly provided by ENI S.p.A. and available on the VIDEPI list, together with surface geologic–stratigraphic knowledge of Plio–Quaternary evolution from the literature. Examples of negative vs. positive reactivation of inherited structures in fold and thrust belts are highlighted. Here, we present an example from the external domain of the Marche Apennines, which displays interesting reactivation examples from the subsurface geology explored. The study area shows significant evolutionary differences with respect to the northern sector of the Marche region previously investigated by the same research group. The areal distribution of the main structures changes north and south of the ENE–WSW oriented discontinuity close to the Conero promontory. Based on the old tripartite classification of the Pliocene, the results of this work suggest a strong differential subsidence with extension occurring during the Early Pliocene and principal compressive deformation starting from the Middle Pliocene and decreasing or ceasing during the Quaternary. The main structure in this area is the NNW–SSE Coastal Structure, which is composed of E-vergent shallow thrusts and high-angle deep-seated normal faults underneath. An important right-lateral strike–slip component along this feature is also suggested, which is compatible with the principal NNE–SSW shortening direction. As mentioned, the area is largely characterized by tectonic inversion. Starting from Middle Pliocene, most of the Early Pliocene normal faults became E-vergent thrusts.

Oil formations of Azerbaijan, their lithographic and geochemical characteristics

Petroleum sediments in Azerbaijan have been researched and described by now in the form of complexes. Not only oil and gas deposits, but also the fields and accumulations of bitumen, bituminized rocks and oil shales are associated with these sediments. Furthermore, there are iodine, brom, the components of natural soda and so on in the oil, oil products and sediments as well. Alongside with it, a great amount of valuable metals present in the content of oil, produced water, bitumen and oil shales as an addition. This circumstance dictates the necessity of formation division of oil sediments. There are ten oil formations: Upper Pliocene-Lower Pleistocene, oil bearing-terrigenic; Middle Pliocene, oil-gas-bituminous-terrigenic; diatom-oil bearing-sand-clay; Miocene, oil-bituminous-sand-aleurite; Upper Oligocene-Miocene, oil bearing-terrigenic-carbonate; Eocene, oil bearing-clay-sand-marly; Upper Cretaceous, oil bearing-carbonate; Lower Cretaceous, oil bearing-terrigenic-carbonate; Upper Jurassic, oil bearing-sand-aleurite.

Something Scary Is Out There: Remembrances of Where the Threat Was Located by Preschool Children and Adults with Nighttime Fear

Young children frequently report imaginary scary things in their bedrooms at night. This study examined the remembrances of 140 preschool children and 404 adults selecting either above, side, or below locations for a scary thing relative to their beds. The theoretical framework for this investigation posited that sexual-size dimorphism in Australopithecus afarensis, the presumed human ancestor in the Middle Pliocene, constrained sleeping site choice to mitigate predation. Smaller-bodied females nesting in trees would have anticipated predatory attacks from below, while male nesting on the ground would have anticipated attacks from their side. Such anticipation of nighttime attacks from below is present in many arboreal primates and might still persist as a cognitive relict in humans. In remembrances of nighttime fear, girls and women were predicted to select the below location and males the side location. Following interviews of children and adult questionnaires, multinomial log-linear analyses indicated statistically significant interactions (p < 0.001) of sex by location for the combined sample and each age class driven, in part, by larger frequencies of males selecting the side location and females selecting the below location. Data partitioning further revealed that males selected the side location at larger frequencies (p < 0.001) than the below location, whereas female selection of side and below locations did not differ significantly. While indicative of evolutionary persistence in cognitive appraisal of threat locations, the female hypothesis did not consider natural selection acting on assessment of nighttime terrestrial threats following the advent of early Homo in the Late Pliocene.