Smectite, illite, and early diagenesis in South Pacific Gyre subseafloor sediment

Subseafloor sedimentary life in the South Pacific Gyre.

The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1-1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths ...

Smectite/Illite Distribution and Diagenesis in the South Timbalier Area, Northern Gulf of Mexico

Porosimetry Measurement of Shale Fabric a N D Its Relationship to Illite/smectite Diagenesis

-The extent of illite/smectite (I/S) reactions is linked with quantitative measurements of shale fabric in a suite of samples from a lower Frio Formation well. Greater illitization of the I/S clays is found in laminated shales that possess a larger pore surface area/pore volume (SA/V) of 3.21 x 106 cm-~ than the adjacent massive shale lithofacies with a SA/V of 1.97 x 106 cm -~. Mean pore diame...

dSED: a database tool for modeling sediment early diagenesis

Mathematical modeling of sediment early diagenesis always involves choosing and describing a set of chemical reactions and processes that is both self-consistent and sufficient for the problem at hand. This critical choice is always a compromise between describing the system’s complexity in all details and using a manageable set of reactions with known or obtainable parameters such as equilibri...

Compositional Variation in Component Layers in Natural Illite/smectite

-Published chemical data for suites of mixed-layer minerals from diagenetic sedimentary rocks, hydrothermally altered tufts, and a metasomatic bentonite bed indicate that the layer charge and composition of the different components of illite/smectite (I/S) differ from one geological environment to another. It appears that the composition of the elemental smectite and illite layers in the I/S is...