ABSTRACT

Cyclic strata of the Holder Formation (Virgilian, New Mexico) were deposited across a Pennsylvanian shelf-to-basin transition during a time when sea level fluctuated over tens of meters. Cement-stratigraphy studies indicate abundant calcite precipitation from low-temperature fresh water within shelf, shelf-crest, and shelf-edge marine limestones. Freshwater cementation occurred during 15 periods of intraformational subaerial exposure. These early cements are least abundant in basin and lagoon limestones. The distribution of the early cement zones suggests that cementation was controlled by paleotopography, stratigraphic position below subaerial exposure surfaces, lithology, and configuration of the paleoaquifer system.

Distribution of early calcite cements provides new data for interpretation of cycles, diagenetic systems, and porosity evolution in petroleum reservoirs. Trace-element analyses support a low-temperature, freshwater origin for the early cements. Cement-stratigraphy studies, fluid-inclusion analyses, and trace-element analyses indicate a later cement that occluded remaining limestone porosity precipitated from a sodium- and calcium-rich brine at a temperature of about 100°C. Stratigraphic reconstruction dates this cementation as Cretaceous or later. Fluorescent, oil-filled fluid inclusions were trapped along fractures in the late cement, indicating oil migration during or after late-stage cementation.

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