نتایج جستجو برای: clastic rocks
تعداد نتایج: 22678 فیلتر نتایج به سال:
we present new whole major and trace elements data for a suite of adakitic dacite to rhyolite rocks from the sahand region. these rocks formed in the pliocene to pleistocene during the the collision between the arabian and eurasian plates following subduction of neo–tethys ocean. these subvolcanic intrusions were emplaced into late cretaceous and eocene sedimentary، volcano–clastic and volcanic...
We developed records of clastic sediment flux to 13 alpine lakes in Peru, Ecuador, and Bolivia, and compared these with independently dated records of regional glaciation. Our objectives are to determine whether a strong relationship exists between the extent of ice cover in the region and the rate of clastic sediment delivery to alpine lakes, and thus whether clastic sediment records serve as ...
There is an amazing array of concretions throughout the sedimentary record Earth, and now iron oxide examples (“blueberries”) recognized in several regions Mars. Two questions address current state knowledge on nodular cemented mineral masses as well coloration patterns. Collectively authigenic cements patterns chronicle past diagenetic conditions, particularly clastic rocks.
Introduction: Shocked rocks are known from various planetary bodies of the solar system including Earth, Moon, Mars, and several types of asteroids. It was first recognized on Earth that stages of progressive shock metamorphism can be defined [1,2,3,4] and this concept was later on confirmed for lunar rocks [5] and meteorites [6,7,8]. Initiated by the IUGS “Subcommission on the Classification o...
New velocity data in addition to literature data derived from sonic log, seismic, and laboratory measurements are analyzed for elastic silicate rocks. These data demonstrate simple systematic relationships between compressional and shear wave velocities. For water-saturated elastic silicate rocks, shear wave velocity is approximately linearly related to compressional wave velocity and the compr...
a r t i c l e i n f o a b s t r a c t Rock alteration and rind formation in analog environments like Antarctica may provide clues to rock alteration and therefore paleoclimates on Mars. Clastic sedimentary rocks derived from basaltic sources have been studied in situ by martian rovers and are likely abundant on the surface of Mars. However, how such rock types undergo alteration when exposed to...
Fine grained sedimentary rocks, both clastic and carbonate, are believed to be the most abundant rock type on the Earth‟s surface (Picard, 1971; Blatt, 1982). Fine grained rocks appear to constitute somewhere in the region of 70% (Holmes, 1937) and 80% (Clarke, 1924) of all the sediment ever produced. In sedimentology the size grade scale most commonly used is that which was introduced by Udden...
The correct positioning of deep wells to monitor groundwater and entrained contaminants is greatly aided by using remote sensing methods. The geologic setting at the Anniston Army Depot (ANAD) consists of a sequence of fractured dolostones and clastic rocks that have been thrust-faulted, creating a highly complex and heterogeneous aquifer. The drilling of deep bedrock groundwater monitoring wel...
Fossil specimens of the exclusively oceanic calcareous nannoplankton were found only in the upper 200 m of the Cape Roberts Project 3 (CRP-3) cores. These assemblages are depauperate and sporadic in occurrence. The majority of the assemblages contain fewer than 4 species, indicating a severe palaeoecological restriction. The clear domination of these assemblages by reticulofenestrid species, co...
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