نتایج جستجو برای: siltstone
تعداد نتایج: 295 فیلتر نتایج به سال:
[1] We report on frictional properties of rocks within the 3-D crustal volume surrounding the San Andreas Fault Observatory at Depth (SAFOD). Samples include lithologies adjacent to the San Andreas Fault (SAF) in the subsurface, SAFOD borehole rocks, and synthetic fault gouge composed of talc, serpentinite, and quartz. Granodiorite, arkosic sandstone, and siltstone samples from the SAFOD boreho...
For underground mining and construction, it is important to obtain a discontinuities’ model of rocks for simulations to evaluate rock stability around the working space and fluid flow in these rocks. We have developed a method using the fractal property of acoustic emission (AE) source distribution to construct a feasible crack distribution model. We confirmed the usefulness of the model throug...
Continental siltstones of the Mesoproterozoic Copper Harbor Formation, Michigan contain macroscopic structures of a size and morphological complexity commonly associated with fossils of eukaryotic macroorganisms. A biogenic origin for these structures would significantly augment the Proterozoic continental fossil record, which is currently poor, and also add to a growing body of sedimentologica...
Patterns of plant distribution by palaeoenvironment were examined across the Pennsylvanian-Permian transition in North-Central Texas. Stratigraphically recurrent packages of distinct lithofacies, representing different habitats, contain qualitatively and quantitatively different macrofloras and microfloras. The species pools demonstrate niche conservatism, remaining closely tied to specific hab...
The compositional record of the AND-2A drillcore is examined using petrological, sedimentological, volcanological and geochemical analysis of clasts, sediments and pore waters. Preliminary investigations of basement clasts (granitoids and metasediments) indicate both local and distal sources corresponding to variable ice-volume and ice-flow directions. Low abundance of sedimentary clasts (e.g.,...
Shales are defined as fine-grained terrigenous sediments and rocks that contain 50% or more of terrigenous, and generally argillaceous, clastic components less than 0.062 mm in size. In the shales, clay-size components often dominate their rock properties, such as density, plasticity, parting, compatibility and swelling. Generally the size boundary between clay and silt is 4μm, but most clay mi...
Compressions and impressions of an isoetalean lycopsid, comprising lower portions of stems, lobed bases, attached rootlets, and rounded rootlet scars, discovered in Late Devonian (Famennian) rocks of Clinton County, north-central Pennsylvania, Appalachian Basin, USA, are here described as Otzinachsonia beerboweri, gen. et sp. nov. These specimens demonstrate unequivocally the existence of the i...
New fossil discoveries are reported from the Grammajukku Formation at Luobákte south of Lake Torneträsk in northern Swedish Lapland, including a fauna Small Shelly Fossils (SSF) limestone bed uppermost part formation and new occurrences brachiopods trilobites siltstones lower formation. The moderately diverse SSF is first its kind Caledonides includes record tommotiid Lapworthella schodackensis...
The Nahr Umr Formation is considered one of the main reservoirs produced in southern Iraq. It important siliciclastic deposits Cretaceous sequence Iraq oilfields. Zubair oil fields ZB-190 and ZB-047 were chosen to study areas. This depends on available core cutting samples determine facies analysis, depositional environments, petrographic characteristics diagenesis processes. Based description ...
The work pursued basic objectives: to study the structure of sedimentary strata, identify sediment units corresponding specific sedimentation stages late Holocene and evaluate factors that influenced their formation in Vistula Lagoon. For achievement goals, well-known methods were used. thickness silt deposits was measured by a hand drill. grain size analysis bottom sediments determined mass co...
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