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Fossils, animal tracks or burrows and even raindrop impressions are sometimes preserved on shale bedding surfaces. Shales may also contain concretions consisting of pyrite, apatite, or various carbonate minerals. [34] Shales that are subject to heat and pressure of metamorphism alter into a hard, fissile, metamorphic rock known as slate.
Lignite – Soft, brown, combustible, sedimentary rock; Limestone – Type of sedimentary rock; Marl – Lime-rich mud or mudstone which contains variable amounts of clays and silt; Mudstone – Fine grained sedimentary rock whose original constituents were clays or muds; Oil shale – Organic-rich fine-grained sedimentary rock containing kerogen
Underground soft-rock mining is a group of underground mining techniques used to extract coal, oil shale, potash, and other minerals or geological materials from sedimentary ("soft") rocks. [1] Because deposits in sedimentary rocks are commonly layered and relatively less hard , the mining methods used differ from those used to mine deposits in ...
East of the Grand River, the clay shale is largely replaced by silty gray shale, hard silty gray mudstone, and thin platy gray siltstone. [6] The red shale fades in intensity and thickness toward the south. South of Columbus, the color fades to reddish-brown and exists only as a bed a few feet thick between bluish or bluish-gray Bedford Shale. [7]
At this site, soft bodied creatures were preserved, some in whole, by the activity of mud in a sea. Solid skeletons are, generally, the only remnants of ancient life preserved; however, the Burgess Shale includes hard body parts such as bones, skeletons, teeth, and also soft body parts such as muscles, gills, and digestive systems.
The biota of the Burgess Shale appears to be typical of middle Cambrian deposits. [6] Although the hard-part bearing organisms make up as little as 14% of the community, [6] these same organisms are found in similar proportions in other Cambrian localities. This means that there is no reason to assume that the organisms without hard parts are ...
The dominant lithology within the Bright Angel Shale is greenish shale that is composed largely of illite and varying amounts of chlorite and kaolinite. A reddish brown coloration is imparted to a number of the sandstone and siltstone beds by the high percentage of hematitic ooids and iron oxide cements that they contain.
Cannel coal from the Pennsylvanian of NE Ohio. Cannel coal or candle coal is a type of bituminous coal, [1] also classified as terrestrial type oil shale. [2] [3] [4] Due to its physical morphology and low mineral content cannel coal is considered to be coal but by its texture and composition of the organic matter it is considered to be oil shale. [5]