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The sedimentary appearance of the thin laminations led to early interpretations that the deposits formed exclusively or mainly by exhalative processes onto the seafloor, hence the term SEDEX. However, recent study of numerous deposits indicates that shallow subsurface replacement is also an important process, in several deposits the predominant ...
Sedimentary exhalative (SEDEX) deposits account for 40% of total world zinc production, 60% of lead and a significant proportion of silver. Despite their economic importance however, sedex deposits are relatively rare. A worldwide compilation of sedex deposits indicates that about 70 are known, of which 24 have been or are being mined.
For example, sedimentary exhalative deposits (SEDEX), are a class of ore deposit formed on the sea floor (sedimentary) by exhalation of brines into seawater (exhalative), causing chemical precipitation of ore minerals when the brine cools, mixes with sea water, and loses its metal carrying capacity.
Molybdenite occurs in high temperature hydrothermal ore deposits. Its associated minerals include pyrite , chalcopyrite , quartz , anhydrite , fluorite , and scheelite . Important deposits include the disseminated porphyry molybdenum deposits at Questa, New Mexico and the Henderson and Climax mines in Colorado .
Franklyn Van Houten's discovery of a consistent geological pattern in which lake levels rose and fell is now known as the "Van Houten cycle". His studies of phosphorus deposits and banded iron formations in sedimentary rocks made him an early adherent of the snowball Earth hypothesis postulating that the planet's surface froze more than 650 Ma ...
The aim of sedimentology, studying sediments, is to derive information on the depositional conditions which acted to deposit the rock unit, and the relation of the individual rock units in a basin into a coherent understanding of the evolution of the sedimentary sequences and basins, and thus, the Earth's geological history as a whole.
Knowledge of sediment transport can be used to properly plan to extend the life of a dam. Geologists can use inverse solutions of transport relationships to understand flow depth, velocity, and direction, from sedimentary rocks and young deposits of alluvial materials. Flow in culverts, over dams, and around bridge piers can cause erosion of ...
Rampura Agucha is a zinc-lead sulfide deposit that is located in the Sikar belt which is part of the Aravalli-Delhi orogen. [4] [5] The Bhilwara belt is mostly metasedimentary, metamorphosed dolomite and a small amount of igneous rocks. [5] [6] The deposit was originally a sedimentary exhalative deposit before experiencing a metamorphic event. [2]