University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 12-2001 Diagenesis of Upper Cambrian Mount Simon Sandstone in the Illinois Basin - Microscale Investigation of Basinal Fluid Migration and Mass Transfer Zhensheng Chen University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Geology Commons Recommended Citation Chen, Zhensheng, "Diagenesis of Upper Cambrian Mount Simon Sandstone in the Illinois Basin - Microscale Investigation of Basinal Fluid Migration and Mass Transfer. " PhD diss., University of Tennessee, 2001. https://trace.tennessee.edu/utk_graddiss/3284 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Zhensheng Chen entitled "Diagenesis of Upper Cambrian Mount Simon Sandstone in the Illinois Basin - Microscale Investigation of Basinal Fluid Migration and Mass Transfer." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Geology. Claudia I. Mora, Major Professor We have read this dissertation and recommend its acceptance: Lee R. Riciputi, Steven G. Driese, Michael E. Essington Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a dissertation written by Zhensheng Chen entitled "Diagenesis of Upper CambrianMount Simon Sandstone in the Illinois Basin - Microscale Investigation of Basinal Fluid Migration and Mass Transfer." I have examined the final copy of this dissertation fo r fo rmand content and recommend that it be accepted in partial fulfillment of the requirements fo r the degree of Doctor of Philosoph , with a major in Geology. � � Claudia I. Mora, Major Professor We have read this dissertation and �mmend it��tanc�: � a: ��, Lee JR. Riciputi { ' ·-1 DIAGENESIS OF UPPER CAMBRIAN MOUNT SIMON SANDSTONE IN THE ILLINOIS BASIN­ MICROSCALE INVESTIGATION OF BASINAL FLUID MIGRATION AND MASS TRANSFER A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Zhensheng Chen December 2001 Acknowledgments This research was sponsored by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Science, U.S. Department of Energy, under contract DE-AC05-000R22725 with Oak Ridge National Laboratory, managed by UT­ Battelle, LLC, with supports fromresearch funding to Dr. Lee R. Riciputi of Oak Ridge National Laboratory. Additional funding provided by Carden research funds to Dr. Claudia I. Mora from the University of Tennessee, a GSA Research Grant-in-Aid and a Sarif Scholarship to ZC. I would like to express my gratitude to the Department of Geological Sciences, University of Tennessee fo r granting me graduate teaching and research assistantships. Special thanks go to Drs. Claudia I. Mora, Lee R. Riciputi, Steven G. Driese, and Michael E. Essington who served on my committee and generously offered me all the help I asked for. I am grateful to Drs. Mostafa Fayak and Otto Kopp, and Mr. Allen Patchen at UTK for their assistance in SIMS and CL analyses. Dr. Neil S. Fishman of the U.S. Geological Survey in Denver provided a series of Mount Simon Sandstone borehole samples and informative reviews of my manuscripts. Dr. Steven Driese provided outcrop samples of the Mount Simon Sandstone from Wisconsin. I thank Drs. Robert J. Bodnar at Virginia Polytechnic Institute, Lawrence A. Taylor at University of Tennessee, and Kip V. Hodges and William Olszewski in Massachusetts Institute of Technology fo r allowing me access to their analytical laboratories. I am grateful fo r constructive reviews of part of this dissertation by Drs. S. Diehl, M. Goldhaber, and M. Henry. ii I would like to express my gratitude to all faculty members and graduate students in our department. For more than 1,500 days at UT, I have received countless help and all kinds of greetings from them. Finally, I am gratefulto my wife, Hanshen, for taking care of me through all these years at the University of Tennessee. lll Abstract A series of investigations were conducted to evaluate microscale evidence fo r basinal fluidmigration in the Illinois basin during diagenesis of the Upper Cambrian Mount Simon Sandstone. Samples were examined using transmitted light and cathodoluminescence (CL) petrography, fluid inclusion analysis, and Secondary Ion Mass Spectrometry (SIMS) analysis of 180/160 ratios and trace element compositions. Preliminary investigation of in situ .laser ablation 40Ar-39Ar age dating techniques on authigenic K-feldspar overgrowths was also completed. Two major generations of quartz overgrowths are observed, on the basis of transmitted light and CL petrography and fluidinclusion studies. High-resolution ( 100 JJ.m x 100 JJ.m), gray-scale images of CL in authigenic quartz overgrowths were acquired using the electron microprobe. Generation 1 quartz overgrowths have low intensity, medium- to dark- gray CL and are associated with fluidinclusion homogenization temperatures (Th) of60 - 95 °C. Generation 2 quartz overgrowths have light-gray CL and are related to fluidinclusion Th of 100 - 145 °C. Th decreases from the southern part of the basin towards the north. Burial temperatures estimated by stratigraphic reconstructionand thermalhistory modeling did not exceed 60 - 90 °C, thus, passage of at least two generations of basinal fluid flow, at temperatures similar to or slightly elevated relative to burial temperature (Th = 60 - 145 °C) through the Mount Simon Sandstone are indicated. Salinities of these Na-Ca-K-Mg-Cl-H20 fluids vary fr om 18 wt% to 25 wt% NaCl equivalent, suggesting that both diagenetic fluids were highly saline basinal brines. Ion-microprobe oxygen isotope analyses of authigenic K-feldspar and quartz reveal a south-to-north-increasing trend in o180 values. Average K-feldspar o180 (V- lV SMOW) values increase systematically from+ 14 ± 1 %o in the southernmostand deepest borehole samples from Illinois to +24 ± 2o/oo inthe northernmost outcrop samples in Wisconsin. A similar south-to-north trend was observed for quartz overgrowths (22 ± 2o/oo to 28 ± 2o/oo). Within-sample 8180 variations of up to 9o/oo are much greater than analytical precision of the ion probe. This may be, in part, the result of sampling diffe rent generations of cements, as supported by CL and fluid inclusion studies in quartz. CL zones within quartz overgrowths were analyzed to evaluate 8180 values in different generations of quartz cements. Generation 1 quartz cements have 8180 values that are equal to (within analytical precision) or greater than (up to 6.8o/oodif ference) generation 2 quartz cements. Overall, however, generation 1 cements are isotopically­ enrichedrelative to generation 2 cements. Constraints on fluid compositions using fluid­ inclusion temperatures that were point-matched to 8180 values of quartz overgrowths containing these fluid inclusions reveal two distinct diagenetic fluids, correspondingto generation 1 (T < 95 °C) and generation 2 (T > 95 °C) fluids. The 8180 values of generation 1 fluidare about -5%o inthe southernportion of the basin and increase to­ O%o in the northernpart of the basin; 8180 values of generation 2 fluid increases from­ +2o/oo inthe south to - +7o/oo in the north. For the generation 1 diagenetic event (T < 95 °C), fluidtemperatures are consistent with burial temperatures in the deeper part of the southernbasin, where the fluidmay have originated. Fluid temperatures in the northern part of the basin are lower than in the southernbasin, but still higher than burial temperatures. v Ion-microprobe studies of authigenic K-feldspar and quartz reveal that Rb, Sr, Ba, Pb, Fe, Mg, B, Ti, and Cl are present in trace amounts in authigenic. K-feldspar. In quartz cements, K, AI, Fe, B, Ti, Mg, and Cl were detected. Strongly covariant relationships among Sr-Ba-Pb-Rb, Na-Mg-Ca-Cl, and K-Al in authigenic cements were attributed to their similar geochemical behaviors and incorporation modes, continuous chemical changes in the fluidduring migration and cement precipitation, and the requirements of solid solution charge compensation. Concentrations ofBa, Sr, Rb,Pb, Fe, Ca, and Ce in diagenetic fluidswere estimated on the basis of trace element contents in authigenic K­ fe ldspar and distribution coefficientsbetween sanidine and hydrothermal fluids. No correlation between fluidcom positions and positions in the basin (south to north) is apparent. Total K+Na+Li+Mg+ Ca concentrations are significantly higher in generation 2 quartz cement, compared to generation 1 cements; B and K are both notably enriched in generation 2. These differences suggest that later brines had a different composition. The lack of regional trends indicates more local control of the physiochemical environment on trace element concentrations in authigenic minerals, compared to their oxygen isotope or fluidinclusion compositions. Preliminary trials of in situ UV-laser probe 40ArP 9Ar dating of authigenic K­