Experimental Compaction of Ooids under Deep-Burial Diagenetic Temperatures and Pressures: ABSTRACT

Abstract

Modern ooid sand particles were experimentally compacted at temperatures of 150°and 200°C (302°and 392°F) and at pressures varying between 824 and 1,565 kg/cm2 (11,700-22,250 psi) consistent with pressures caused by 3.5-6.5 km (11,000-21,000 ft) of overburden. Bulk volume reductions of 21-26% under the above experimental conditions were more substantial than usually considered reasonable. Particle breakage and deformed particle contacts developed that are comparable to those reported for similar lithologic characteristics from the rock record. Pressure solution can be produced successfully on compaction in ooid sand particles. This demonstrates that initial pore-volume reduction through mechanical grain adjustments and ultimate pressure solution are the major processes in the diagenetic evolution of limestones. This appears to solve the problem of mass balance. Additionally, ooids were noted to have been plastically deformed, giving rise to longitudinal and concavo-convex contacts. End_of_Article - Last_Page 454------------