GEOCHEMICAL CHARACTERIZATION AND “SOURCING” OF THE BEEZLEY CHALCEDONY, ROZA MEMBER, COLUMBIA RIVER BASALT GROUP, WASHINGTON ------------------------------------------------------------------------------- A Thesis Presented to the Faculty of the Department of Earth and Atmospheric Sciences University of Houston ------------------------------------------------------------------------------- In Partial Fulfilment of the Requirements for the Degree Master of Science ------------------------------------------------------------------------------- By Shawn Darrin Larkin May 2015 GEOCHEMICAL CHARACTERIZATION AND “SOURCING” OF THE BEEZLEY CHALCEDONY, ROZA MEMBER, COLUMBIA RIVER BASALT GROUP, WASHINGTON ___________________________________ Shawn D. Larkin APPROVED: ___________________________________ Dr. Thomas J. Lapen, Chairman ___________________________________ Dr. Henry S. Chafetz ___________________________________ Dr. Brett R. Lenz ___________________________________ Dean, College of Natural Sciences and Mathematics ii Acknowledgements I express my sincere thanks and appreciation to Tom Lapen, for agreeing to advise me and for putting up with my nonsense throughout this grueling voyage. I thank Henry Chafetz for serving on my committee and I express my gratitude to Brett Lenz and the Grant County (WA) Public Utility District for supplying the project from the beginning and for financial support. My deepest appreciation goes to Steve Jensvold for lugging me around the Beezley Hills looking for raw material and for providing so much important background for the field area, for which I am greatly indebted. Also, thanks to Steve and his family for graciously putting me up in their home during field work. My perpetual gratefulness goes to Andy Miner at CWU for digitizing maps and locations, producing data, answering loads of questions and keeping me updated on Beezley Hills background during the compiling of this thesis. I am very grateful to Jinny Sisson for schooling me on the use of the microprobe and providing background on CL measurements, and I am thankful to Peter Anderson who helped me work the microprobe even though I’m sure he had more important things to do. I express my love and gratitude to my parents, Lyle and Maryann, who have never given up on me, even when I seemed to be accomplishing little. My thanks go to my children, Elijah and Rachel, who are always happy to see me at the end of a long day at school. Lastly, my love and appreciation will always be with my wife, Kimberly, who believes in me even when I do not and who has stuck by me even when things seemed to be going nowhere. Thank you all—I could not have done it without you! iii GEOCHEMICAL CHARACTERIZATION AND “SOURCING” OF THE BEEZLEY CHALCEDONY, ROZA MEMBER, COLUMBIA RIVER BASALT GROUP, WASHINGTON ------------------------------------------------------------------------------- An Abstract of a Thesis Presented to the Faculty of the Department of Earth and Atmospheric Sciences University of Houston ------------------------------------------------------------------------------- In Partial Fulfilment of the Requirements for the Degree Master of Science ------------------------------------------------------------------------------- By Shawn Darrin Larkin May 2015 iv Abstract The Beezley Chalcedony is a high-quality chert source that occurs in the Beezley Hills, northern Grant County, Washington. Archaeological collections from sites in and near Grant County are visually similar to the Beezley Chalcedony. This study aims to geochemically characterize the chalcedony source locales material as a context for future comparisons with the Clovis tools. The Beezley Chalcedony formed from Middle Miocene diatomite-rich lacustrine sediments of the Squaw Creek Member of the Ellensburg Formation that is situated between the older Frenchman Springs Member and the Roza Member of the Wanapum Basalt Formation, Columbia River Basalt Group. Laser ablation ICPMS trace element analyses of chalcedony from seven site locations in the Beezley Hills and one in the nearby Quincy Potholes area reveal significant trace element variation for several elements (e.g., Ge, U, V, Y, and Zr). Five locations in the Beezley Hills display marked spatial variation in trace element concentrations and element ratios. The variations in trace element concentrations may be inherited from the source diatomite and minor shale units in the Squaw Creek Member or are related to element mobility during diagenesis. These trace element variations can be used as tools for linking the artifacts to source locations and for tracking artifact trade routes. v Table of Contents 1 Introduction 1 1.1 Purpose of Study 1 1.2 Statement of Problems 2 2 Geologic Background 4 2.1 Area of Interest 4 2.2 Chert Fundamentals 9 3 Archaeological Background 14 4 Methodology 17 4.1 Field Methodology 17 4.2 Analytical Methodology 18 5 Results 22 5.1 Visual Analysis 22 5.2 Major Element Compositions 22 5.3 X-ray Element Mapping 22 5.4 Cathodoluminescence 25 5.5 Rare Earth Element Composition 25 5.6 Trace Element Composition 29 5.7 Compositional Variation 35 6 Discussion 41 vi Table of Contents (continued) 6.1 Source of Silica 41 6.2 Redox-sensitive Trace Elements 42 6.3 Spatial Geochemical Variation 42 6.4 Diagenesis 43 7 Conclusions 48 7.1 Conclusions 47 7.2 Recommendations for Future Work 48 8 References 49 9 Appendix – Data Tables 56 vii List of Figures 1 Extent of Columbia River Basalt Group, Wanapum Basalt and 5 approximate field area 2 Columbia River Basalt Group stratigraphy near the Beezley Hills, WA 6 3 Map of Grant County, WA, Beezley Hills field area, and Roza member 11 4 Close-up map of Beezley Hills field area, and Roza member 12 5 Clovis-type projectile point examples 15 6 Raw chert boulder from the Ellensburg Formation, Beezley Hills, WA 20 7 Backscatter Electron image and X-ray element maps for site GCPUD008 24 8 Chondrite-normalized Rare Earth Element plot (averaged) for all 26 source locations 9 Trace element concentration plot (average U & Th) for all sites versus 27 published data 10 Trace element concentration plot (average Th & Al) for all sites versus 28 published data 11 Germanium vs zirconium concentration plot for all source locations 32 12 Yttrium vs zirconium concentration plot for all source locations 33 13 Yttrium vs boron concentration plot for all source locations 34 14 Boron/Yttrium vs vanadium concentration plot for all source locations 36 15 Boron/Yttrium vs germanium concentration plot for all source locations 37 viii List of Figures (continued) 16 Compositional variation plot for selected elements from site GCPUD008 39 17 Compositional variation plot for selected elements from site WP75SJ7 40 18 Selected trace element concentration plot for spatial variation, Ge vs B, 44 Ge vs Y 19 Selected trace element concentration plot for spatial variation, Ge vs Zr, 45 V vs B/Y ix List of Tables 1 Percent silica oxide measurements from site GCPUD008 23 x Chapter 1: Introduction 1.1 Purpose of Study Dozens of archaeological artifact sites have been discovered throughout central Washington State and Grant County, according to the Washington State University Museum of Anthropology; however very few published articles exist about these sites and where the associated lithic raw material may have been quarried (Daugherty, 1956; Huckleberry et al., 2003). Several apparent source locations exist in the Beezley Hills, west of Ephrata, Washington, in northern Grant County (Lenz 2010). None of the raw material has ever been examined geochemically or otherwise “sourced”. The purpose of this study is to measure the trace element concentrations and geochemically characterize the Beezley Chalcedony. By providing this information, it is hoped that in the future, artifacts may be traced to the Beezley Hills source and that the data will allow geologists and archaeologists to gain understanding into possible source locations and source travel times (Huckell et al., 2011), distances between mining areas and possible caches (Malik- Selivanova et al., 1998), or differentiating between visually similar materials (Hoard et al., 1993). Ancient people around the world have been shaping stone tools for thousands of years. Easily workable material includes obsidian, chert, flint, quartzite, basalt, petrified wood, even bones or shells. Materials that fracture conchoidally are particularly easy to shape by trained workers (called “flintknappers”). Such material can be made into very sharp implements like arrowheads, knives, spear points, or scrapers that may last in surficial deposits for millennia. 1 Paleoindian people frequently did not settle in places where necessary resources occurred. To obtain such materials, trade routes were established. These trade routes were sometimes hundreds of kilometers in length (Healy et al., 1984). In order to distinguish materials that are visually similar but may have been quarried in different locations, geologists must examine the geochemistry of each artifact and match it to the geochemistry of known source-material. These provenance analyses, or artifact “sourcing,” give workers copious information used to decipher trade routes, procurement strategies, economic conditions, agricultural practices, and daily habits. 1.2 Statement of Problems As stated above, no geochemical work has ever been performed on the Beezley Chalcedony to date. This material, clearly workable and of high quality, may well have been used, carried, and traded far from the source locations in the Beezley Hills. As evidenced