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University Microfilms International 300 N INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction. 1. The sign or “target” for pages apparently lacking from the document photographed is “Missing Page(s)”. If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure complete continuity. 2. 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These prints are available upon request from the Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases the best available copy has been filmed. University Microfilms International 300 N. Zeeb Road Ann Arbor, Ml 48106 8308945 Gregg, Jay Mason TOE ORIGIN OF XENOTOPIC DOLOMITE TEXTURE Michigan State University PH.D. 1982 University Microfiims International300 N . Zeeb Road. Ann Arbor. MI 48106 PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages ^ 2. Colored illustrations, paper or print _____ 3. Photographs with dark background 4. Illustrations are poor copy ______ 5. Pages with black marks, not original copy ______ 6. Print shows through as there is text on both sides of page ______ 7. Indistinct, broken or small print on several pages _ 8. Print exceeds margin requirements _____ 9. Tig htly bound copy with print lost in spine ______ 10. Computer printout pages with indistinct print ______ 11. Page(s) ___________ lacking when material received, and not available from school or author. 12. Page(s) ___________ seem to be missing in numbering only as text follows. 13. Two pages numbered Text follows. 14. Curling and wrinkled pages ______ 15. Other____________________________________________________________________ University Microfilms International THE ORIGIN OF XENOTOPIC DOLOMITE TEXTURE by Jay Mason Gregg A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Geology 1982 Frontplate: "The Entrance to Marble Canyon, Culberson County, Texas." B ackplate: "Galena Dolomite Outcrop Locality 33, Grant County, Wisconsin. THE ORIGIN OF XENOTOPIC DOLOMITE TEXTURE Jay M* Gregg Ph.D* D is s e rta tio n Michigan State University Department of Geology 1982 ERRATA Abstracts line 3» omit "edral" line 9. omit "ing" p. i i i s ACKNOWLEDGMENTS line 9* Dr* K. C. Lohmann of the University of Michigan provided the oxygen and carbon isotope data and aided in it's interpretation• line 15, "Kable" should be "Kahle" p* 7: line 21, "The term is" should read "The terra a i s " eq« 1» "(i-N )"should read "(1-Na)" p* 11i line 3» should read "theoretically predicted a" p, 19s line 2, "10 m" should read "10 pm" p. 24: line 21, "idiotopic-A" should read "idiotopic-E" p. 25: line 12, "idiotopic-B" should read "idiotopic-S" p. 26: Table 2 caption, "idiotopic-B" should read "idiotopic-S" p« 5 1 J l i n e 31 should read (1011), (4051) p* 78s line 3* should read "the fossils are" p. 83* line 12, "JFl" should read "JF" p* 86s line 14, "xenotopic-C" should read "xenotopic-P" p. 89: line 19* "(table 4 and fig* 54)" should read "(table 6 and fig* 49)" p* 9 1: line 1, "table 6" should read "table 7" p. 95: line 20, read "C0^“" at end of the line p* 9 8: line 17, should read "begin to equally favor" p* 102i line 24, should read "was probably rock dominated" p* 103: line 8, " Table 6" should read "Table 7" p* 105: line 7» should read "is that it resulted" p« 107: line 17» should read " observation of xenotopic" ABSTRACT The Origin of Xenotopic Dolomite Texture by Jay Mason Gregg Xenotopic dolomite texture, commonly observed in ancient rocks, is defined as a mosaic of anhedra with irregular or curved intergrain boundaries and usually undulose extinction. Xenotopic dolomite edral texture is similar in appearance to neomorphic limestone textures. Xenotopic texture contrasts with idiotopic dolomite texture (euhedral to subhedral crystals with straight intergrain boundaries) that is common in both Cenozoic and ancient dolomites. Texture may be controlled by the temperature at which crystals grow. Crystal growth theory predicts that at low temperature, a ing smooth crystal surface is energetically favored, atoms are added to crystal faces layer by layer, with dislocations acting as nucleating sites. This results in faceted crystals and euhedral to subhedral crystal mosaics. Above a "critical roughening temperature" (CRT) a rough surface is energetically favored, surface nucleation does not require dislocations and atoms are randomly added to the crystal surface resulting in non-faceted growth and an anhedral crystal m osaic. It is hypothesized that a "critical roughening temperature" exists for dolomite above 25°C. Xenotopic dolomites are produced by dolomitization of limestone and/or neomorphic recrystallization of dolomite at elevated temperature (above CRT) after burial. Idiotopic dolomites are produced below CRT by near surface processes. Calcite has a CRT below 25°C and, therefore, produces annhedral grain mosaics (neomorphic texture) both at near surface and elevated temperature. Synthetic xenotopic dolomite was produced in the laboratory by dolomitization of aragonite and calcite skeletal fragments and by recrystallization of nonstoichiometric Cenozoic dolomites at 250°C and 300°C. Xenotopic dolomite resulted from the metamorphic recrystallization of the idiotopic Hueco dolomite (Permian), Texas near the Marble Canyon intrusion, at temperature between 350°C and 600°C. Hydrothermal dolomitization of peridase-calcite marble near the intrusion also resulted in a xenotopic texture. Xenotopic dolomite in the Galena Group (Ordovician), Wisconsin, was produced by neomorphism of a pre-existing dolomite during the emplacment of lead-zinc sufides at temperatures between 80° and 120°C. In the Trenton Formation (Ordovician), Michigan, xenotopic dolomite replaced limestone, during the migration of hot (>50°C) fluids along fracture systems. Xenotopic dolomite was not observed in Cenozoic dolomites which were subjected only to near surface temperatures. Dedicated to the Memory o f my F ather Jay B. Gregg ii ACKNOWLEDGEMENTS I wish to express my deep appreciation to Dr. Duncan F. Sibley for suggesting this topic and providing guidance and encouragement throughout this project. I gratefully acknowledge the help and suggestions of Drs. David T. Long, James H. Fisher and especially Dr. Thomas A. Vogel, who in itially suggested a relationship between dolomite texture and temperature. Mr. David J. Delgado of Phillips Petroleum Co. provided invaluable assistance in providing stratigraphic information and o u tcro p lo c a tio n s fo r th e Galena Group. Mr. Stu McDonnald o f th e University of Michigan provided valuable assistance in locating and sampling Trenton Formation core. Mr. Joe Williams of Texas Architectural Aggregates, San Saba, Texas kindly granted me permission to collect samples in Marble Canyon. 1 also wish to thank Dr. Kenneth A. Jackson of the Bell Laboratories, Murray H ill, N.J. and Dr. Charles F. Kable of Bowling Green State University for valuable discussions during the course of th is work. Dr. Lynton S. Land of the University of Texas, Dr. Carl M. Cooper and Mr. Donald L. Childs of Michigan State University College of Engineering made valuable suggestions for the design of hydrothermal bombs used in this study, Drs. Stanley Flegler and Karen Baker of the Michigan State University Center for Electron Optics for the use of and expert instruction on their scanning electron microscopes. iii This study was partially supported by grants from the National Science Foundation (no. EAR-8023736), The Geological Society of America (no. 2837-81), Sigma Xi, and Shell Oil Company. 1 also wish to thank Sun Oil Company and Hunt Energy Corporation for contributing to my support during the first year of my graduate study at Michigan State University. Thanks are due to many friends in the Geology Department who helped me get through four years of study. Particularly Dr. Thomas R. Taylor whose study of the Trenton Formation was concurrent with mine and porvided invaluable insights and information, and Mr. Alan D. Trippel without whose assistance 1 doubt 1 could ever have obtained a single thin section. For their encouragement and friendship. I wish to thank Bud Ifoyer, Mary Jank, Melissa Wardlaw, Mick Hartzel, Abolfazl Jameossanaie, Tom Fox, Dan Orr, Loretta Satchel and Carl Karlowski.
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