Conodont assemblages of late Pennsylvanian cycles in North Central Texas /
| Main Author: | |
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | A study was made of the distribution of Late Pennsylvanian conodonts from six cycles along the Eastern Shelf of the Midland basin. Conodont samples were taken from the Wayland, Necessity, Finis, Colony Creek, Upper Winchell and Upper Salesville cycles. Sedimentological data from each of the sections were used in conjunction with macrofossii and oxygen isotope data to reconstruct the paleoenvironmental setting in which the conodonts lived. One purpose of the study was to describe and characterize conodont biofacies. Four assemblages and two sub-assemblages can be recognized for North Texas cycles that can be called conodont biofacies. Their distribution along an environmental gradient, from shallow to deep water is; Adetognathus, Streptognathodus - Idiognathodus (Streptognathodus elegantulus and Streptognathodus simulator), Idioprioniodus and Gondolella biofacies. The Adetognathus, Streptognathodus - Idiognathodus (Streptognathodus elegantulus and Streptognathodus simulator) were determined using Cluster Analysis. The Idioprioniodus and Gondolella biofacies were determined intuitively. Another purpose was to test a model for conodont distribution developed for the Midcontinent of North America. The Midcontinent model assumes a pelagic mode of life for the conodont animal. This assumption fits with the data obtained from cycles in north-central Texas. Conodont recovery is not as great as from samples in the Midcontinent due to the higher rate of sedimentation in Texas. Cycles in north central Texas can be correlated to Midcontinent cycles on fossil content in the two areas. The oxygen isotope data serve to place some absolute depth ranges on these Texas cycles. 3y analogy with modern oceans the minimum sea level change associated with most of these cycles was 70 meters, with the maximum change being 170 meters. Combining conodont occurrences with isotope data, the depths at which the conodont animal lived is inferred to be at least 70 meters for the Gondolella-bearinq animal. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Geology." |
| Physical Description: | xii, 159 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |