نتایج جستجو برای: ultramafic bedrock
تعداد نتایج: 4457 فیلتر نتایج به سال:
Introduction: The petrogenesis of the low-Ti lunar ultramafic glasses is critical to the understanding of volcanic processes on the Moon. Popular petrologic models developed to explain the formation of these glasses involve high pressure melting of a variety of sources, including primordial, garnet bearing, lunar mantle and depleted lunar magma ocean (LMO) cumu-lates [1,2,3,4]. Following the hi...
[1] We conducted a detailed study of subsurface flow and water table response coupled with digital terrain analysis (DTA) of surface and subsurface features at the hillslope scale in Panola Mountain Research Watershed (PMRW), Georgia. Subsurface storm flow contributions of macropore and matrix flow in different sections along an artificial trench face were highly variable in terms of timing, pe...
[1] The formation of inner gorges cut into bedrock has been explained as relief rejuvenation by fluvial incision in response to rapid base level drop, repeated glaciations, frequent pore pressure–driven landsliding focused at hillslope toes, or catastrophic outburst flows from natural dam failures. Prominent inner gorges occur in soft Mesozoic Bündner schist and lower Tertiary flysch units of t...
In an actively deforming orogen, maintenance of a topographic steady state requires that hillslope erosion, river incision, and rock uplift rates are balanced over timescales of 10–10 years. Over shorter times, < 10 years, hillslope erosion and bedrock river incision rates fluctuate with changes in climate. On 10-year timescales, the Marsyandi River in the central Nepal Himalaya has oscillated ...
The objective of this study was to investigate the possibility of a generic rating curve with a small number of adjustable parameters for the restricted class of bedrock step-pool rivers. The motivation for this study arose from Utah Valley University’s long-term program of groundwater development in the Trans-Mexican Volcanic Belt, which requires hydrographs for bedrock step-pool rivers near r...
We present evidence for a naturally occurring quasicrystal consisting of micron-sized grains of Al63Cu24Fe13 with icosahedral symmetry embedded in a sample of khatyrkite (nominally, (Cu,Zn)Al2) obtained from the Khatyrka ultramafic zone of the Koryak Mountains in the northern half of the Kamchatka Peninsula.
Species composition patterns and vegetation-environment relationships were quantified for high-elevation rock outcrops of the Southern Appalachian Mountains, an infrequent and insular habitat in a forested landscape. Outcrops occur over a wide geographic range encompassing extensive variation in both geology and climate. Geographic-scale factors interact with site-scale factors to produce varia...
[1] Bedrock erosion in mountain river channels ultimately sets the erosion rate of the surrounding hillslopes and the rate of sediment supply to the channels. The supply of coarse bed sediment acts as a dampening effect on further erosion by depositing an alluvial cover that temporarily obscures the bedrock. For landscapes where the residence time of the alluvial bed cover is comparable to the ...
The Big Jim complex is a concentrically zoned ultramafic to felsic plutonic complex which intruded the pelitic Chiwaukum schist. Most of the major plutonic rock types (from websterite through hornblendite, gabbronorite, hornblende gabbro and diorite, to granodiorite) enclose harzburgite and metaperidotite xenoliths similar to foliated metaperidotite lenses included in the Chiwaukum schist. The ...
This contribution assesses the availability of catabolic energy for microbial life during water-rock reactions in the flanks of mid-ocean ridges, where basaltic and ultramafic rocks interact with circulating seawater. In addition to equilibrium thermodynamic computations, results for kinetic reaction paths are presented. In these calculations, it is assumed that dissolution of olivine and basal...
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