Sedimentary rocks lithology

The district is composed of sedimentary rocks of the pre-Paleogene Shimanto Supergroup (dominantly shale and sandstone) and Quaternary andesitic and dacitic volcanic rocks. The Shimanto Supergroup is comprised of shale, sandstone and their alternations. Although no fossil data are available, the age of sedimentation is thought to be middle to upper Cretaceous age from its lithology (Izawa et al., 1990). The Shimanto... 

Sedimentary rocks that are most likely to meet the first three criteria are unfractured shale, clay, siltstone, anhydrite, gypsum, and salt formations. Massive limestones and dolomites (i.e., carbonates with no continuous fracturing and solution channels) can also serve as confining layers. Then-suitability must be determined on a case by case basis. The fourth criterion has no relationship to lithology. 

The Pebble deposit is located in the Kahiltna terrane, near the boundary between two lithologic packages Jurassic and older magmatic-metamorphic rocks to the southeast, and an assemblage of Mesozoic volcaniclastic and sedimentary rocks overlain by Tertiary volcanic rocks, to the northwest. An extended discussion of the regional geology is given in Kelley etal. (this volume). 

These trends in lithologic features of the sedimentary rock mass can be a consequence of both evolution of the surface environment of the planet and recycling and post-depositional processes. It has been argued (e.g., Mackenzie, 1975 Veizer, 1988) that both secular and cyclic evolutionary processes have played a role in generating the lithology-age distribution we see today. For the past 1.5-2.0 billion years, the Earth has been in a near present-day steady state, and the temporal distribution of rock types since then has been controlled primarily by... 

As might be anticipated, the trends observed for lithologic types versus age are reflected in trends in the chemistry and mineralogy of carbonates and other sedimentary rocks. Discussion of some of these latter trends, emphasizing first the overall trends for the past 3.8 billion years, then those of the Phanerozoic, are presented below. 

The information most often required for engineering purposes is the lithological and structural information. These stratigraphic rock units or map units normally do not have different constituent rock types individually demarcated but these may be found mentioned collectivity in the legend. This tends to drastically limit their usefulness for engineering purposes. However, in spite of this limitation there is one map unit referred to as the Quaternary that does assist directly in engineering site investigations of sedimentary rocks. 

In this study. Possibility of this phenomenon in the tunnel route of Line 2 Tabriz metro is discussed. The tunnel route is mostly located on alluvial sediments and moderately cemented sedimentary rocks. With this variety of lithological units, occurrence of mixed face in some sections of the tunnel is probable. 

Hoek, E., Marinos, P. Marinos, V. 2005. Characterization and engineering properties of tectonically undisturbed but lithologically varied sedimentary rock masses under publication. Int J Rock Mech Min Sci, 42(2) 277-285. 

Much of the world s currently minable uranium is found in vein-like deposits of uncertain origin. They consist of three general types of unequal importance. Most important are unconformity-related deposits and vein-like deposits in meta-morphic rocks. Least important and probably of different origin are vein-like deposits in sedimentary rocks. The origin of all three types is a matter of much conjecture. Major unsolved genetic questions are the source of the uranium and its mode of transport, the source of the mineralizing solutions, the nature and role o f reductants and the control exerted on uranium deposition by structural and lithologic features of the host rocks. Unconformity-related deposits and vein-like deposits in metamorphics commonly occur in brecciated and foliated metamorphic rocks in stable Precambrian Shield areas. They contain about 24.4% of the Western world s reasonably assured 30 uranium resources. 

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