Burial diagenesis

N NaCl exchanges used to study diagenetic I/S (44). Thus, the illite layers remaining in the WD clays after three Sr-exchanges may be of comparable stability to those formed by burial diagenesis. 

The pattern in Figure 8 is distinct from that for randomly interstratifled I/S produced from bentonite by burial diagenesis (Figure 9). Fixed interlayer cation content for the latter clays is relatively constant at about 0.55 equivalents per illite layer for clays that contain less than 50% illite layers (53). 

JOHNS (W.D.) and SHIMOYAMA (A.), 1972. Clay minerals and petroleum-forming reactions during burial diagenesis. Bull. Arne. Assoc. Pet. Geol. 56. 

PERRY (E.A.) and H0WER (J.), 1970. Burial diagenesis in Gulf Coast pelitic sediments. Clays and Clay Min. 18, 165-78. 

Burial effects. We have been involved in several studies in the Himalaya and Tibet that illustrate the need to carefully evaluate the potential effects of burial diagenesis on 818Osc values before using them to reconstruct paleoelevation. The first comes from Penbo in southern Tibet... 

Several water compositions are plotted on the stability diagrams in Figure 8.2. It can be seen that at shallow Earth surface pressures and temperatures, seawater plots in the stability field of dolomite whereas solutions of average river water composition and most shallow groundwaters plot in the field of calcite. With burial of carbonate sediments and elevated P and T, the dolomite field shrinks, but subsurface fluid compositions evolve toward a composition in equilibrium with dolomite. This conclusion is probably one of the most important arguments for the formation of dolomite during deep burial diagenesis (see also Hardie, 1987). Thermodynamic considerations favor this reaction path, as well as the fact that... 

Aside from mineral stabilities, the behavior of the CO2-H2O system with increasing P and T is also important to an understanding of the deep burial diagenesis of carbonate rocks. One reaction of interest, which represents the summation of K0 and Ki (see Chapter 1) for the carbonic acid system, is... 

Burial diagenesis and subsequent alteration of chalk The Overall Diagenetic Pathway... 

Many chalks undergoing burial diagenesis in the present oceanic realm and those exposed on land were originally pelagic foram-nannofossil calcite oozes. However, calcareous oozes deposited in the periplatform environment are compositionally more complex. These oozes represent transitional carbonate deposits found between carbonate banks and the deep sea (Schlager and James,... 

Figure 8.21. Strontium, 818C, and 8180 composition of Miocene chalk, northern Jamaica. Subaerially exposed chalks are low in Sr, and depleted in 180 and l3C relative to chalks that have never been exposed to subaerial conditions. The line is the Sr-8180 trend for Shatsky Rise limestones recovered by the DSDP program (Matter et al., 1975). Notice the similarity between the Sr-8180 trends for the Shatsky Rise limestones, which have undergone burial diagenesis, and that for the Jamaican chalks, which have been subjected to meteoric processes. (After Land, 1986.)...

Czemiakowski L.A., Lohmann K.C. and Wilson J.L. (1984) Closed system marine burial diagenesis Isotopic data from the Austin Chalk and its components. Sedimentology 31, 863-877. 

Heydari E. and Moore C.H. (1989) Burial diagenesis and thermochemical sulfate reduction, Smackover Formation, southeastern Mississippi salt basin. Geology 17, 1080-1084. 

James, N.P. and Bone Y. (1989) Petrogenesis of Cenazoic temperate water calcarenites, South Australia A model for meteoric/shallow burial diagenesis of shallow water calcite sediments. J. Sediment. Petrol. 59, 191-203. 

Moore C.H. and Druckman Y. (1981) Burial diagenesis and porosity evolution, Upper Jurassic Smackover, Arkansas and Louisiana. Am. Assoc. Petrol. Geol. Bull. 65,597-628. 

Scholle P.A. and Halley R.B. (1985) Burial diagenesis Out of sight, out of mind. In Carbonate Cements (eds. N. Schneidermann and P.M. Harris), pp. 309-334. Society Economic Paleontologists and Mineralogists Special Publication 36, Tulsa, OK. 

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