Preservation stratigraphy

The patterns of carbonate accumulation and preservation in the deep sea contain important information about the chemistry and fertility of ancient oceans. Numerous studies have now shown that variations in the carbonate system have occurred on a variety of timescales, both within and between ocean basins. On a local or even regional scale, such variations can often be used as a correlation tool. This has come to be known as preservation stratigraphy . 

Oldest preserved supracrustal rocks, Isua greenstone belt stratigraphy includes quartz-rich sedimentary rocks... 

Early calcites (both generalized and concretionary) preserve IGVs typically in the range of 30-40%. In terms of cement stratigraphy, early calcite precedes quartz cement but postdates siderite and some of the kaolinite (Fig. 3A). Early calcite is typically poikilotopic. Extensive replacement of detrital feldspars by early calcite is observed (Fig. 3B), but the calcite is pervasive in its distribution and not strongly localized on the feldspars. 

Ordovician faunas and stratigraphy. The brachiopod faunas are often exquisitely preserved and have been documented and illustrated in considerable detail in many monographic works. Hints and Roomusoks (1997) have provided details of brachiopod distributions through the Ordovician together with a summary of previous studies. Three groups of sections have been analysed. The two East Baltic successions, characterising the North Estonian confacies belt and the Livonian Tongue... 

The excavation of a site also means the destruction of the local stratigraphy and structures. Therefore, any trenching should be done in the most preservative way to avoid damage both for the ongoing and any future studies at the same site. Moreover, excavation material should be backfilled carefully, especially on cultivated lands. For example, preservation of the natural soil can be critical and can be done by separating it from other excavated materials and putting it back at the end of the trench study. 

Association between the sample and the seismic event of interest is clearly critical. In part, this comes down to stratigraphy, but also depends to some extent on the sample material itself. Fragile materials such as plant fragments are Ukely to be in their primary deposits because they are unlikely to survive significant reworking. Well-preserved plant macrofossils are therefore to be preferred over... 

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