Abstract: Carbonate Sedimentology and a Return to the Rocks

Lloyd C. Pray

The principle(s) of uniformity or uniformitarianism and use of the present as the key to the past have permitted important progress in carbonate sedimentology. Research on modern sediments and environments and on processes of modern depositional and diagenetic realms will continue to provide essential leverage for interpreting ancient carbonate rocks.

Encouraging in the past 2 decades of accelerated research on ancient carbonate rocks has been a return to study of the rocks themselves. Increased utilization of microscopy used by such as Sorby, Cullis, Caxeaux, and Sander; of cathode luminescence and SEM microscopy; and of such microanalytic techniques as atomic absorption, the microprobe, and mass spectrometry are resulting in interpretive rewards in deciphering the geologic record.

Discouraging, but not necessarily a flaw in methodologic uniformitarianism for interpreting ancient carbonate rocks, has been modern model mesmerism and the use of present-to-past methodology without adequate knowledge of one or both ends of the analogy. Also inhibiting progress is distrust of the rocks unless a modern analog is available, and uncritical demonstration that a known modern analog is applicable to interpretation of specific rocks or facies. Absence of a known present analog should not, but often does, inhibit rigorous genetic evaluation of ancient carbonate rocks.

The return to study of the rocks themselves will prove even more rewarding when accompanied by increased attention to facies relations and to spatial and temporal aspects commonly discernible only through critical field or subsurface studies. Ancient carbonate rocks will continue to fascinate and perplex geologists.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma