The Baker Cave Bison Remains: Bison Diminution and Late Holocene Subsistence on the Snake River Plain, Southern Idaho

The role of bison in the prehistoric subsistence in southern Idaho is not fully understood. Bison remains from Baker Cave, a late Holocene archaeological site dating to cal A.D. 1042-1265, however, provide evidence of pre-contact subsistence strategies in the region. This thesis focuses on the paleoecology of bison and their role in prehistoric subsistence on the Snake River Plain (SRP). The ecological study of bison focuses on the hypothesized trans-Holocene diminution in bison body size in southern Idaho, while a second study focuses on how these animals figured into prehistoric responses to seasonal fat scarcity. Although bison diminution and its ecological determinants are well understood on the Great Plains, the history of diminution west of the Rocky Mountains is less clear. Bison morphometrics from Baker Cave present the opportunity to assess bison diminution on the Snake River Plain. Bison morphometrics from Baker Cave are indistinguishable not only from other late Holocene bison on the Snake River Plain but iv also from late Holocene bison from the Great Plains. Further, the Baker Cave bison are smaller than early Holocene bison from the Great Plains and Snake River Plain. These results suggest morphological similarity between Snake River Plain bison and Great Plains bison through the Holocene, pointing to similar bottom up ecological constraints on body size. Although bison are common components of SRP archaeofaunas, their role in prehistoric subsistence is poorly understood. To shed light on this problem, I hypothesize that the Baker Cave bison assemblage resulted from hunters seeking skeletal fat. I test predictions drawn from this hypothesis with assemblage-level patterns in element representation, impact scar distribution, and fragmentation. These assemblage-level patterns track the skeletal fat utility of elements. These patterns, combined with winter procurement evidenced by fetal remains, support the hypothesis that fat-seeking behavior was a response to winter fat scarcity. A comparison with smaller bison assemblages from southern Idaho suggests that this fat-seeking behavior might have persisted as far back as the middle Holocene, although this requires confirmation from future studies

Volcanism of the Eastern Snake River Plain, Idaho: A comparative planetary geology-guidebook

The Planetary Geology Field Conference on the central Snake River Plain was conceived and developed to accomplish several objectives. Primarily, field conferences are sponsored by the National Aeronautics and Space Administration to draw attention to aspects of terrestrial geology that appear to be important in interpreting the origin and evolution of extraterrestrial planetary surfaces. Another aspect is to present results of recent research in a region. A final objective of this conference is to bring together investigators of diverse backgrounds who share a common interest in the Snake River Plain. The Snake River Plain appears to be similar in surface morphology to many volcanic regions on the Moon, Mars, and possibly Mercury. Therefore, the Snake River Plain, in combination with the relatively good state of preservation, the lack of forests or other heavy vegetation, and the good network of jeep trails, is an area nearly ideal for analog studies

The geology and geothermal setting of the Magic Reservoir Area, Blaine and Camas Counties, Idaho

Journal ArticleThe Magic Reservoir area straddles the Blaine- Camas county line in south-central Idaho, along the northern boundary of the central Snake River Plain. The rocks exposed at Magic Reservoir include a 5.8- million-year-old rhyolite flow, the Pliocene Square Mountain Basalt, multiple cooling units of a 5.6- million-year-old rhyolite ash-flow tuff, a 4.7-millionyear- old rhyolite dome, and Quaternary basalt flows and sediments. These newly reported ages for the rhyolites at Magic Reservoir reveal that they are the youngest, westernmost silicic volcanic rocks presently known in the Snake River Plain. They represent an anomalously young rhyolitic event that may include the Moonstone Mountain rhyolite dome to the northwest and the previously dated (Armstrong and others, 1975) 3-million-ycar-old Wedge Butte rhyolite dome to the southeast of Magic Reservoir. The area is cut by numerous normal faults trending northwest, northeast, and west. The northwest-trending faults are the dominant structures. They form a horst block at Hot Springs Landing and parallel the regional structural grain. The geothermal resource at Magic Reservoir occurs within the elevated heat flow province at the northern margin of the Snake River Plain. The system is probably controlled by the deep, convectivce circulation of fluids along faults at the intersection of the Hot Springs Landing horst with west- and northeast-trending fractures. Although the volcanic rocks in the Magic Reservoir area are young, they are too old to contribute any magmatic heat to the geothermal system

A fixed sublithospheric source for the late Neogene track of the Yellowstone hotspot: Implications of the Heise and Picabo volcanic fields

The Heise and Picabo volcanic fields of eastern Idaho are part of the more extensive time-transgressive Yellowstone-Snake River Plain hotspot track. Calderas associated with these two silicic volcanic fields are buried under 1 to 3 km of younger basalt, so their locations and eruption record histories have been based on analysis of silicic units along the margins of the eastern Snake River Plain along with some limited geophysical data. A 1.5 km borehole penetrating through basalt into underlying silicic rocks provides new data we used to reassess caldera locations and the timing of eruptions of these volcanic fields. Using these new caldera locations, we calculate an extension-adjusted rate of 2.35 cm/yr for the North American plate over the last 6.66 m.y. and a velocity of 2.30 cm/yr over the 10.27 m.y. Recalculation of a previously determined plate velocity-based migration of the deformation field surrounding the eastern Snake River Plain yields an extension-adjusted rate of 2.38 ± 0.21 cm/yr. These migration rates all fall within the previously published range of North American plate velocities of 2.2 ± 0.8 cm/yr, 2.4 cm/yr, and 2.68 ± 0.78 cm/yr based on a global hot spot reference frame. The consistency of these rates suggest that over the last 10 m.y., the Yellowstone hot spot is fixed with respect to the motion of the North American plate and therefore consistent with a classical deep-sourced hotspot model

A Precambrian History of Cratonic North American Crust Beneath the Snake River Plain, Idaho

Granulite xenoliths erupted in Neogene basalts, and a rare outcrop of Precambrian basement along the northern margin of the Snake River Plain (SRP), can be used as windows into the origin and stabilization of the lower crust of southern Idaho. Previous work to determine the nature of the lower crust beneath the Snake River Plain was conducted on a suite of xenoliths exposed in Southern Idaho at Square Mountain (SM), Craters of the Moon National Monument and Preserve (CRMO), and the Spencer-Kilgore (SK) area (Leeman, 1979; Leeman et al., 1985; Matty, 1984; Wolf et al., 2005), as well as on a basement outcrop at House Mountain, near Mountain Home, ID (Alexander, 2006). This study uses U/Pb geochronology and Hf isotope geochemistry to determine the history of formation and stabilization of the lower crust of the SRP within the context of other surrounding Precambrian basement terranes of North America. Results of this investigation reveal that two distinct terranes comprise the lower crust of Southern Idaho. The Kilgore-Craters terrane formed and stabilized \u3e2.7 Ga and the Square Mountain terrane at \u3e2.5 Ga. Hf isotope ratios and U-Pb geochronology of inherited cores of zircons reveal that the Snake River Plain formed in part from older, reworked crust. Archean geologic events and Hf signatures of the Snake River Plain match those of the Wyoming Province, indicating the Snake River Plain is a westward extension of the Wyoming Province. The Kilgore-Craters terrane is equivalent to the northern Beartooth-Bighorn magmatic zone and the Montana Metasedimentary province area, and the Square-Mountain/Grouse Creek terrane is a westward extension of the Southern Accreted Terranes of the Wyoming Province

INL Seismic Monitoring Annual Report: January 1, 2011 - December 31, 2011

During 2011, the Idaho National Laboratory Seismic Monitoring Program evaluated 21,928 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 2,063 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these events, 16 were small-to-moderate size earthquakes ranging in magnitude (M) from 3.0 to 4.4. Within the 161-km radius, the majority of 941 earthquakes (M < 4.4) occurred in the active regions of the Basin and Range Province with only six microearthquakes occurring in the Snake River Plain. In the northern and southeastern Basin and Range, eight earthquake swarms occurred and included over 325 events. Five of the Snake River Plain earthquakes were located within and near the northern and southern ends of the Great Rift volcanic rift zone. All have anomalously deep focal depths (16 to 38 km) and waveforms indicative of fluid movement at mid- and lower-crustal levels and are a continuation of activity observed at Craters of the Moon National Monument since 2007. Since 1972, the Idaho National Laboratory has recorded 55 small-magnitude microearthquakes (M = 2.2) within the eastern Snake River Plain and 25 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument

INL Seismic Monitoring Annual Report: January 1, 2011 - December 31, 2011

During 2011, the Idaho National Laboratory Seismic Monitoring Program evaluated 21,928 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 2,063 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these events, 16 were small-to-moderate size earthquakes ranging in magnitude (M) from 3.0 to 4.4. Within the 161-km radius, the majority of 941 earthquakes (M < 4.4) occurred in the active regions of the Basin and Range Province with only six microearthquakes occurring in the Snake River Plain. In the northern and southeastern Basin and Range, eight earthquake swarms occurred and included over 325 events. Five of the Snake River Plain earthquakes were located within and near the northern and southern ends of the Great Rift volcanic rift zone. All have anomalously deep focal depths (16 to 38 km) and waveforms indicative of fluid movement at mid- and lower-crustal levels and are a continuation of activity observed at Craters of the Moon National Monument since 2007. Since 1972, the Idaho National Laboratory has recorded 55 small-magnitude microearthquakes (M = 2.2) within the eastern Snake River Plain and 25 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument

Groundwater Monitoring and Field Sampling Plan for Operable Unit 10-08

This plan describes the groundwater sampling and water level monitoring that will be conducted to evaluate contaminations in the Snake River Plain Aquifer entering and leaving the Idaho National Laboratory. The sampling and monitoring locations were selected to meet the data quality objectives detailed in this plan. Data for the Snake River Plain Aquifer obtained under this plan will be evaluated in the Operable Unit 10-08 Remedial Investigation/Feasibility Study report and will be used to support the Operable Unit 10-08 Sitewide groundwater model

Late Tertiary to Quaternary Geology and Landscape Evolution along the Snake River Plain, Southwestern Idaho

The geology of the Snake River Plain in the vicinity of Melba and Murphy, in southwestern Idaho, provides evidence for changes that have occurred over the last several million years, during the late Cenozoic. Here, the local and regional geology is described and interpreted within the context of events that have contributed to the present-day landscape

Planetary geology, stellar evolution and galactic cosmology

Field studies of selected basalt flows in the Snake River Plain, Idaho, were made for comparative lunar and Mars geological investigations. Studies of basalt lava tubes were also initiated in Washington, Oregon, Hawaii, and northern California. The main effort in the stellar evolution research is toward the development of a computer code to calculate hydrodynamic flow coupled with radiative energy transport. Estimates of the rotation effects on a collapsing cloud indicate that the total angular momentum is the critical parameter. The study of Paschen and Balmer alpha lines of positronium atoms in the center of a galaxy is mentioned