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The new thought is that these ocean currents were slowed by blooms of microscopic marine primary producers, which allowed for the settlement of organic-rich sediments at the seafloor, producing many of the economically productive black shale beds that are present today. To this day it remains an intensely researched subject by scholars and ...
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Sedimentary organic matter includes the organic carbon component of sediments and sedimentary rocks. The organic matter is usually a component of sedimentary material even if it is present in low abundance (usually lower than 1%). Petroleum (or oil) and natural gas are particular examples of sedimentary organic matter.
Ordovician ophiolite in Gros Morne National Park, Newfoundland Chromitic serpentinite, Bay of Islands Ophiolite, Lewis Hills, Newfoundland. An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks.
Kerogen is a complex mixture of organic chemical compounds that make up the most abundant fraction of organic matter in sedimentary rocks. [12] As kerogen is a mixture of organic materials, it is not defined by a single chemical formula. Its chemical composition varies substantially between and even within sedimentary formations.
Other, assorted organic matter, detritus. Stream substrate can affect the life found within the stream habitat. Muddy streams generally have more sediment in the water, reducing clarity. Clarity is one guide to stream health. Marine substrate can be classified geologically as well. See Green et al., 1999 for a reference.
Organic palynofacies considers all the acid insoluble particulate organic matter (POM), including kerogen and palynomorphs in sediments and palynological preparations of sedimentary rocks. The sieved or unsieved preparations may be examined using strew mounts on microscope slides that may be examined using a transmitted light biological ...
As a result of criticism related to the limited scope and applicability of this definition, a more flexible and generic definition has been proposed that (1) includes a broader range of human activities, (2) considers more sediment types apart from post-settlement alluvium, and (3) respects the spatial (nonuniform) and temporal (time-transgressive) variability of LS: