The mineral composition of manganese-bearing minerals is dependent on how the nodules are formed; sedimentary nodules, which have a lower Mn 2 + content than diagenetic, are dominated by Fe-vernadite, Mn-feroxyhyte, and asbolane-buserite while diagenetic nodules are dominated by buserite I, birnessite, todorokite, and asbolane-buserite.
32.
Krynine ( 1950 ) suggested that the red beds were primarily formed by the erosion and redeposition of red soils or older red beds, but a fundamental problem with this hypothesis is the relative scarcity of red-colored source sediments of suitable age close to an area of red bed sediments in diagenetic ) reddening of the sediment by the dehydration of brown or drab colored ferric hydroxides.
33.
Here between 1967 and 1981, he in association with colleagues Robert Garrels, Hal Helgeson, Abraham Lerman and his many graduate students and national and international colleagues published a number of classic papers involving an interdisciplinary range of scientific topics including early diagenetic processes of reverse weathering and controls on seawater composition, pore water geochemistry, kinetics and thermodynamics of mineral-water reactions, and modeling of Earth's surface environmental system over geological time.
34.
The studies of provenance involve the following aspects : " ( 1 ) the source ( s ) of the particles that make up the rocks, ( 2 ) the erosion and transport mechanisms that moved the particles from source areas to depositional sites, ( 3 ) the depositional setting and depositional processes responsible for sedimentation of the particles ( the depositional environment ), and ( 4 ) the physical and chemical conditions of the burial environment and diagenetic changes that occur in siliciclastic sediment during burial and uplift ".
