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As a consequence, a slightly different set of sedimentary structures develops in turbidites deposited by high-density turbidity currents. This different set of structures is known as the Lowe sequence, which is a descriptive classification that complements, but does not replace, the Bouma sequence. [2]
The Bouma sequence specifically describes the ideal vertical succession of structures deposited by low-density (i.e., low sand concentration, fine-grained) turbidity currents. An alternate classification scheme that is generally called the Lowe sequence exists for the ideal vertical sequence of structures deposited by high-density flows. [2]
The transport and deposition of the sediments in narrow alpine reservoirs is often caused by turbidity currents. They follow the thalweg of the lake to the deepest area near the dam, where the sediments can affect the operation of the bottom outlet and the intake structures. [8]
Although the deposits of all four types of sediment support mechanisms are found in nature, pure grain flows are largely restricted to aeolian settings, whereas subaqueous environments are characterized by a spectrum of flow types with debris flows and mud flows on one end of the spectrum, and high-density and low-density turbidity currents on the other end.
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition.. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different particle sizes are deposited on top of each other. [1]
As water or air slows, the turbidity decreases. The suspended load of the detritus then precipitate. In times of fast movement the bedding may be poorly sorted on the deposition surface and thus is not normally graded because of the quick movement of the material.
Sole markings were first recognized in the Devonian rocks of New York State by James Hall in 1843. [4] Originally, the features found on the undersides of beds were called hieroglyphs, fucoids, and bio hieroglyphs, because of their structure and how they were thought to be created; however, the term sole mark is used by geologists at present.
Before this, it was thought that only turbidity flows were capable of depositing and reworking sediment at depths greater than the continental slope. [1] Hollister and Heezen (1972) [ 5 ] adopted the name contourite for these deposits and provided a list of characteristics that described their sediments.