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The Extent of the White Chuck Tuff, a High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington

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The Extent of the White Chuck Tuff, a High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington Western Washington University Western CEDAR WWU Graduate School Collection WWU Graduate and Undergraduate Scholarship Spring 2004 The Extent of the White Chuck Tuff, a High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington Gerald T. Ladd Western Washington University, [email protected] Follow this and additional works at: https://cedar.wwu.edu/wwuet Part of the Geology Commons Recommended Citation Ladd, Gerald T., "The Extent of the White Chuck Tuff, a High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington" (2004). WWU Graduate School Collection. 671. https://cedar.wwu.edu/wwuet/671 This Masters Thesis is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Graduate School Collection by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. THE EXTENT OF THE WHITE CHUCK TUFF, A HIGH TEMPERATURE PYROCLASTIC FLOW DEPOSIT GLACIER PEAK, WASHINGTON by Gerald T. Ladd Accepted in Partial Completion Of the Requirements for the Degree Master of Science Moheb A. Ghali, Dean of the Graduate School ADVISORY COMMITTEE Chair, Dr. Dr. Scott Babcock Dr. Bernard Housen MASTER’S THESIS In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Western Washington University, I agree that the Library shall make its copies freely available for inspections. I further agree that the copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis project for commercial purposes, or for financial gain, shall not be allowed without my written permission. MASTER’S THESIS In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Western Washington University, I grant to Western Washington University the non-exclusive royalty-free right to archive, reproduce, distribute, and display the thesis in any and all forms, including electronic format, via any digital library mechanisms maintained by WWU. I represent and warrant this is my original work, and does not infringe or violate any rights of others. I warrant that I have obtained written permissions from the owner of any third party copyrighted material included in these files. I acknowledge that I retain ownership rights to the copyright of this work, including but not limited to the right to use all or part of this work in future works, such as articles or books. Library users are granted permission for individual, research and non-commercial reproduction of this work for educational purposes only. Any further digital posting of this document requires specific permission from the author. Any copying or publication of this thesis for commercial purposes, or for financial gain, is not allowed without my written permission. Gerald T. Ladd [email protected] March 9, 2018 The Extent of the White Chuck Tuff, A High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington A Thesis Presented to The Faculty of Western Washington University In Partial Fulfillment Of the requirements for the Degree Master of Science By Gerald T. Ladd May 2004 Abstract The White Chuck Tuff, a massive deposit approximately 15 m thick, caps two terraces in the White Chuck River valley covering an area of approximately 5 km^ at the base of Glacier Peak, Washington. Three major post-glacial eruption cycles from Glacier Peak reportedly occurred approximately from 12,000 to 11,250 years ago (White Chuck Assemblage), from 5,500 to 5,100 years ago (Kennedy Creek Assemblage), and from 1,800 to 250 years ago (recent eruptions). West of Glacier Peak, pyroclastic and lahar deposits from all three episodes are found in drainages out to Puget Sound 100 km away. The White Chuck Tuff has been assumed to be approximately 11, 500 years old (Beget, 1981) and not found west of Camp Creek in the White Chuck River Valley, approximately 17 km from Glacier Peak. Anisotropy of magnetic susceptibility, paleomagnetic, petrographic, and geochemical procedures were conducted to characterize the tuff deposit. Similar laboratory procedures were conducted on five distal pyroclastic deposits to determine if they were unconsolidated runout of the White Chuck Tuff Flow direction, paleomagnetic directions and paleomagnetic poles, mineralogy, and chemical composition of the proximal indurated White Chuck Tuff indicate that it was emplaced as a single unit at temperatures exceeding 580° C. The overall flow direction during emplacement was northwesterly down the White Chuck River Valley. The paleomagnetic directions, mineral and chemical compositions are similar amongst the seven sampling sites. Five distal deposits WC-1, SR-1, SR-2, SR-3, and ST-1 were products of cold to warm (from 22°C to 375°C) debris flows that made their way down the White Chuck IV River Valley into the Sauk and North Fork Stillaguamish River Valleys. The paleomagnetic directions amongst the distal deposits were not well defined. The anisotropy of magnetic susceptibility of these deposits had no preferred orientation of the magnetic fabric indicating that the flow direction and individual clast anisotropy were independent of emplacement mechanisms. A viscous magnetization was measured in many of the pumiceous clasts sampled at all of the cooler distal sites and upward directions were measured in the low unblocking temperature range of 100 to 300° C in many of the samples from these sites. The clasts from these deposits had a previous magnetic history before they came to rest at their present location. The chemistry and mineralogy of all five distal sites is similar and indicate dacitic composition. The virtual geomagnetic pole of distal deposit WC-1 closely corresponds with the 9180 +290/-200 virtual geomagnetic pole of Hagstrum and Champion (2002), which post dates the White Chuck Assemblage. Virtual geomagnetic poles of other distal deposits are not well enough defined to be useful. From field relationships associated with the deposition and location of other deposits (Dravovieh et al, 2003), the Glacier Peak distal deposits were probably produced during the Kennedy Creek Assemblage eruption cycle. The virtual geomagnetic pole of the White Chuck Tuff deposit matches the 12,750 b.p. virtual geomagnetic pole of Hagstrum and Champion (2002). This virtual geomagnetic pole dates the tuffs deposition before the White Chuck Assemblage eruptive cycle. Therfore the previously assumed age of 11,500 b.p. is probably incorrect. V ACKNOWLEDGMENTS This research could not have been completed without the expertise of my committee, Scott Babcock, Russ Burmester, and Bernie Housen; All have been mentors and supporters throughout my graduate career. Other people and organizations that provided support for this project have been: Western Washington University Geology Department: Awarded a research grant for this project. Pacific Northwest Paleomagnetic Laboratory: Facilities used for research and analysis of AMS and paleomagnetic data. US Forest Service: For permission to conduct research in the Glacier Peak Wilderness Area Joe Dragovich: Aiding in fieldwork and thin section sample donation. Field Assistants: Kirk Heim and Dan Bunk assisting with sample collection. Tom and Dianne Ladd: My dad who spent a week in the field hauling 80 pounds of rock cores and drilling equipment; and reading my thesis, giving editing suggestions. Both of my parents have supported me through all of life’s challenges. Heather Ladd: My wife who also spent weekends in the field to assist in sample collection and late nights doing clerical work and editing has supported me through this process and will continue to support me on all of my endeavors. VI Table of Contents Abstract.........................................................................................................iv Acknowledgements.....................................................................................vi List of Figures............................................................................................... ix List of Tables ................................................................................................. x Introduction................................................................................................... 1 Glacier Peak ...................................................................................................5 Regional Setting.........................................................................................................5 Post-Glacial Eruptive History................................................................................5 D escription of D eposits.............................................................................. 10 White Chuck Tuff........................................................................................ 10 Distal Deposits............................................................................................ 16 Methodology of Study..............................................................................21 Field Study and Sampling.........................................................................21 Magnetic Studies......................................................................................... 26 Paleomagmtism...................................................................................26 Anisotropy of Magnetic Susceptibility................................................ 30 Rock Composition
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