Adleman, J.N., Larsen, J.F., Geophysical Institute/Department of Geology and Geophysics, University of Alaska Fairbanks, 99775

M. Ramsey, Department of Geology and Planetary Science, 200 SRCC Building, University of Pittsburgh, Pittsburgh, PA 15260

McGimsey, R.G., Neal, C.A., Wessels, R.L., U.S. Geological Survey, Alaska Volcano Observatory, Anchorage, AK 99508

Black Peak is a 1,032m stratovolcano on the Alaska Peninsula located at 56.53 N, 158.80 W. It is one of approximately 80 historically active volcanic centers along the 2,500km long Aleutian Arc that stretches from southern Alaska to Russia's Kamchatka Peninsula. Ash-flow tuffs from the >10km 3 caldera forming eruption ~4,600 years ago filled the valleys to the west and north. The ice-free caldera floor of Black Peak volcano is occupied by a complex of approximately one dozen overlapping dacitic lava domes. During emplacement, additional domes breeched the eastern caldera wall depositing avalanches partway down the drainages in this area. We sampled each of the domes outcropping in and around the flanks of the caldera. Initial examination of these samples reveals a possible range in bulk composition within the dome field, with differences in amphibole content and matrix glass alteration. Several of the domes contain dark, mafic enclaves with chilled margins, whereas others are enclave free. The purpose of this study is to investigate how these apparent differences in dome mineralogy and bulk composition are detected in the satellite imagery (ASTER, Landsat ETM+, Ikonos) collected for Black Peak volcano, and apply the results to the ground based field observations in order to map changes in the physical and chemical properties of the domes. To compare with the satellite data results, the bulk rock compositions of collected samples will be analyzed using both laboratory thermal emission spectroscopy and XRF. Electron microprobe and standard light microscopic petrographic techniques will also be used to determine specific details about the changes in mineralogy and chemistry within and between each dome. The results of these analyses will be used to construct a satellite based map of the physical and chemical properties of the dome field, augmented by careful ground validation and laboratory analyses. This combined with other studies of Black Peak will lead to a more complete understanding of the volcanic processes that followed the caldera formation. Further, given the significant amount of unstudied and unmapped volcanic regions in Alaska, the use of high resolution satellite data for preliminary investigation of remote volcanoes may be a cost effective and efficient way to assess eruption deposits along the Aleutian Arc, which might otherwise be unstudied for a number of years.

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Submitted: American Geophysical Union Fall Meeting
Date: December 8 - 12, 2003