Periods Of Fossil Filling And Replacement As Indicators Of Climate

Embedded within the gray Permian limestones of the Finlay Mountains, trans-Pecos, Texas, are abundant remains of fusulinids, bryozoans, and brachiopods. Most of the fossil tests which are exposed on weathered surfaces are partially, or wholly, replaced by a form of impure silica. The fusulinids especially are characterized by such replacements and stand out in sharp relief above the weathered surfaces of the limestones that contain them. Besides the one period of silicification exhibited by these fossils, two periods of calcite filling are evidenced also…. These three distinct periods deserve an explanation. As suggested in this paper, local climatic changes might be the explanation desired