magma mixing

Dr. Matthew E. Brueseke

Department of Geology
Kansas State University
108 Thompson Hall
P: (785) 532-1908
F: (785) 532-5159

hardscrabble cs tuff
Below are summaries of current/future projects that will provide you with a better sense of my research interests.  If you are interested in graduate work at K-State in Igneous Petrology/Volcanology/Tectonics, feel free to contact me about any of the projects discussed below.   
saunders gold model Collaborative work with Jim Saunders and Bill Hames (Auburn University), aims to study the detailed relationship between coeval mid-Miocene precious metal mineralization and magmatism in the northern Great Basin.  Essentially the goal of this research is to test the model illustrated to the left (figure from Saunders et al., 2008; Mineralium Deposita) in the Owyhee Mountains, ID and determine the  relationships between local magmatism, ore formation, and host rock type and also whether local mineralization and silicic magmatism was stimulated by periods of enhanced mafic activity.  Peripheral to the local volcanic story is better understanding the local Cretaceous granitoid upper crust to determine whether these rocks could have been a potential crustal melt reservoir for younger silicic activity and if they truly are related to the granitoids of the Idaho Batholith.  This project has been recently funded by NSF.
tarc Stratigraphically juxtaposed beneath mid-Miocene igneous rocks and above Cretaceous granitoid in the Santa Rosa Mountains and Bloody Run Hills of NV (SRBR) is a package of ~35-20 Ma dominantly trachyandesitic to trachydacitic calc-alkaline lava flows.  Similar materials are found across northern Nevada, southern Oregon, and western Idaho.  These lava flows have volcanic arc-like chemical characteristics (they physically resemble "typical" arc-andesites too), but lie ~150-200 km east of the inferred (e.g. Dickinson, 2006; Cousens et al., 2008).   So, myself and colleagues are interested in better understanding the petrogenesis and tectonic affinity of these igneous rocks (e.g. was the late Oligocene - early Miocene volcanic arc really wide?;  do thier regional chemical attributes represent spatial differences in lithospheric thickness and depth to melting?, etc.).  Work is needed to better understand this regional magmatic event.
owyhee basalt This image illustrates a thick package of mafic to intermediate lava flows ( Owyhee Basalt) overlying a thick rhyolite lava flow at Lake Owyhee, OR.  Locally, these lava flows erupted into the Oregon-Idaho graben, soon after voluminous pyroclastic volcanism occurred at the Lake Owyhee volcanic field, just to the south.  Current work is underway to better understand the relationship of mafic through silicic units in this region, by initially studying local mafic-intermediate lava flows and shallow intrusive bodies and their relationship to regional ~16.5-14 Ma equivalents  (e.g. Steens and Columbia River basalts and other intermediate magmas).  Future work will include detailed stratigraphic sampling; if you are interested in doing geology off a boat, send me an e-mail!  Other future work to better understand how intermediate magmas form will be less field-oriented and rely on detailed micro-analytical techniques and osmium geochemistry.  Most of these studies are in collaboration with Bill Hart (Miami U.)     
San Volcanic field The bedrock geology of Kansas is far more exciting than many people might think.  In fact, there are  kimberlites exposed within 20 miles of Manhattan and we nearly lie over the mid-continent rift!   Unfortunately, besides distal Yellowstone tephra, we are lacking local Cenozoic volcanic rocks.  However,  the Southern Rocky Mountain volcanic field is just over the border and is composed of voluminous quantities of erupted materials and numerous large magmatic systems (figure from Lipman  & McIntosh, 2008; GSA Bulletin).  Potential projects include detailed geologic mapping/petrogenesis of a small composite volcano and its relationship to other similar volcanoes and volcanology/petrogenesis of eruptive products from the ~33 Ma Bonanza Caldera.  Thanks to Peter Lipman for introducing me to this area and some of the problems that need study (there is lots of work to do!).    
chisana pillows In collaboration with with Jeff Trop (Bucknell) and Bill Hart (Miami U., I plan on starting a new project to better understand Cretaceous arc magmatism along the southern Alaskan margin.  In the northern portion of Wrangell-St. Elias National Park, thick packages of lava flows and sedimentary strata  (Chisana formation) are exposed in close proximity to similar-aged plutonic bodies.  Overall, the primary goal of the igneous portion of this project is to evaluate the petrogenesis and  plate-tectonic affinity of the magmatic rocks.  The picture to the left depicting pillow basalts from the Chisana package is from Jeff's website.