{"id":25,"date":"2013-09-20T15:40:14","date_gmt":"2013-09-20T20:40:14","guid":{"rendered":"https:\/\/my.dev.vanderbilt.edu\/lilyclaiborne\/?page_id=25"},"modified":"2018-08-14T13:02:39","modified_gmt":"2018-08-14T18:02:39","slug":"research","status":"publish","type":"page","link":"https:\/\/my.dev.vanderbilt.edu\/lilyclaiborne\/research\/","title":{"rendered":"Research Overview"},"content":{"rendered":"

\"IMG_4945\"<\/a>Magmatic Processes at Mount St.\u00a0 Helens Volcano<\/strong><\/p>\n

Zoned zircons record the time-temperature-composition history of the magma in which they grew. Recent development of trace element analysis techniques using SHRIMP-RG (Mazdab and Wooden, 2006), combined with in situ U-Pb and U-series geochronology and the new Ti-in-zircon thermometer (Watson et al., 2006), provides a powerful tool for extracting this information. We have used this approach to delineate the complex history of the Spirit Mountain batholith in southern Nevada, including repeated episodes of crystallization, melt evolution, differentiation, recharge, and transport of magma between storage zones in the shallow, Miocene intrusive system (Claiborne, et al., 2006; Walker et al., 2007). Zircons from individual samples, and even single zircon grains, record temperature variations of up to 100\u00b0C and order-of-magnitude variations in trace element concentration. Unfortunately, the timescales of closely-spaced events recorded by zoning are beyond resolution of in situ (SHRIMP) U-Pb geochronology (>105 years for Miocene zircons). By applying these methods to zircons erupted from very young volcanic systems, including U-series geochronology with its much higher age resolution (~104 years), we anticipate better constraining the timescales of pre-eruptive magmatic processes such as rejuvenation and differentiation, and providing insight concerning the connections between volcanic and plutonic systems.<\/p>\n

We are now also examining glasses and feldspars from throughout the history of the volcano to better understand the dynamics of magma storage and evolution in the Mount St. Helens magmatic system.<\/p>\n

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Zircon as a Record of Magmatic Processes\"\"<\/a><\/strong><\/p>\n

The accessory mineral zircon is commonly used to investigate magmatic systems.\u00a0 I am interested in using this powerful tool, but also in better understanding its crystallization and subsequent behavior so that we can better interpret its records.\u00a0 This includes, especially, how we use its trace element geochemistry to understand the compositions and temperatures of the melts from which it grew.<\/p>\n

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Pre- and Post-supereruption Magmatism (the Peach Spring Tuff)<\/strong><\/p>\n

Our REU program has recently ended.\u00a0 We thank you for your interest, and hope you’ll keep an eye out for papers coming out soon!\"10455194_10152443976310409_2456609471666424655_n\"<\/a>\u00a0 \"10891803_10152951031834876_3522725326514968231_n\"<\/a><\/p>\n

Supereruptions are explosive events that eject more than 1000 cubic kilometers of volcanic material \u2013 capture our imagination and compel us to consider the potential effects of one of Earth\u2019s rarest yet deadliest acts.\u00a0 Comprehending what led to supereruptions in the past is essential to understanding and predicting similar events in places where geologically recent supereruptive activity suggests a threat, including the U.S. (e.g. Yellowstone), South America (southern Andes), Indonesia, and New Zealand.<\/p>\n

This work will investigate the tumultuous magmatic history recorded by the 18- to19-million-year-old volcanic and intrusive igneous rocks in the southern Black Mountains of northwestern Arizona and elsewhere in adjacent California and Nevada. Here, the geologic record includes\u00a0the well-exposed, recently-identified Silver Creek caldera, which produced the\u00a0enormous Peach Spring Tuff (PST) supereruption nearly 19 million years ago.\u00a0The\u00a0PST is\u00a0exposed over 32,000 km2<\/sup> of western Arizona, southeastern California, and southern Nevada.<\/p>\n

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Map sh\"\"<\/a>owing extent of the Peach Spring Tuff (orange) and location of the Silver Creek Caldera<\/em><\/p>\n<\/div>\n

Moreover, the Silver Creek caldera and its immediate environs also offers a stellar\u00a0record of the PST\u2019s immediate magmatic precursors and successors, meaning that we can evaluate the long-term evolution of this volcanic center in order to gain a better understanding of\u00a0how<\/em> and\u00a0why<\/em> supereruptions are generated \u2013 topics that scientists are actively investigating, and to which the geologic record in the southern Black Mountains may provide valuable clues.<\/p>\n

We aim to answer the following supereruption-related questions:<\/p>\n