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Abstract: Dissolution Diagenesis of Agglutinated Foraminifera: Experimental Study

Mervin Kontrovitz, Jerry Marie Slack

The use of agglutinated foraminifera would be enhanced if taphonomic processes were better known. Here, Ammotium salsum (Cushman & Bronnimann) was treated at various temperatures and pressures (T-P), simulating burial.

In organic-rich (12%) mud there is no alteration up to 180° C, 600 atm. At 210° C, 700 atm, terminal chambers begin to deteriorate, disintegrating at 270° C, 900 atm. There are holes and more chamber loss at 300° C, 1000 atm.

In quartz at 100° C, 300 atm, tests are unaltered. At 120° C, 400 atm, grains become detached and sutures deepen; holes appear at 150° C, 500 atm. At 210° C, 700 atm cement is further reduced and terminal chambers deteriorate.

In calcite at 100° C, 300 atm, terminal chambers disintegrate; at 700x large pits are seen. At 120° C, 400 atm, the first chambers remain recognizable; the surface is a jumble of grains with little agglutinating material. Between 120° C, 400 atm and 150° C, 500 atm, tests are destroyed.

Thus, increasing T-P results in characteristic alteration useful to reconstruct T-P conditions, at least under experimental conditions. Further experiments may show differences between taxa.

AAPG Search and Discovery Article #90955©1995 GCAGS 45th Annual Meeting and Gulf Section SEPM, Baton Rouge, Louisiana