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Found 92 matches
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  1. ... , suggestive of resurgence. Some large chaos areas, notably Murias Chaos and Thrace Macula, are associated with clusters of small (<1 km diameter) craters, interpreted as secondary craters. Some chaos areas are surrounded by blobs of matrix material and sometimes small blocks, which may represent ...
  2. ... STUEBEN, Doris, Institute for Mineralogy and Geochemistry, Univ of Karlsruhe, Karslruhe, 76128, Germany Yaxcopoil 1, drilled within the Chicxulub crater, was expected to yield the final proof that this impact occurred precisely at the K-T boundary 65 m.y. ago and caused the end-Cretaceous mass extinction ...
  3. ... compositions distinguish evaporite-rich rocks, basaltic soils, concretion/hematite-rich soils, and basaltic rocks with distinctive compositions. Craters expose evaporite-rich sedimentary rocks from beneath a thin, basaltic regolith. In addition to hematite and jarosite, indicated by MB, APXS chemical ...
  4. ... geology and soil chemistry along a 40 meter-wide corridor along the traverse. Geologic contacts crossed included ejecta blankets from larger impact craters and the regional contact between the lava plains and the Columbia Hills. Traverse observations confirmed that orbital mapping successfully identifies ...
  5. ... -term remobilization and redistribution of tephra following a scoria-cone (violent strombolian) eruption. Initial modeling efforts focused on Sunset Crater, Arizona , and Parícutin , Mexico , and incorporated a simplified mass-balance approach to examine sediment erosion and transport processes in ephemeral ...
  6. ... are Phanerozoic in age, but the first 88% of Earth history (~ 4 billion years) resides in the Precambrian. The Moon is covered with Precambrian craters, but only a few dozen impacts that age have been documented on Earth. Relating evolution to impacts is also a daunting task because “hard parts” didn ...
  7. ... degrees north and south; of these bands, the southern hemispheric zone contains more gully features. Most surveys focused on gullies forming along crater walls; however, the Dao and Harmakhis Valles systems provide a unique opportunity to evaluate gully features with respect to latitude, elevation, ...
  8. ... of high concentrations of LCP are typically restricted to small outcrops in older, Noachian terrains. High olivine abundances have been found in crater floors in Lunae Planum, in crater rims in the southern highlands, and associated with volcanic rocks in and around Syrtis Major. Deposits with hydrated ...
  9. ... are penetrated by the EWDP boreholes south and southwest of the proposed repository. Ground water near Pleistocene-age tufa deposits in southern Crater Flat has &delta;87Sr values between +4.4 and +5.8, similar to those of the deposits. Samples from new boreholes in a small valley north of the Lathrop ...
  10. ... displaced ice blocks kms across embedded in a matrix of disturbed ice, bands of newer ice, cryovolcanoes, domes and pits, and fault scarps. Impact craters pierce the crust, exposing older ice in crater walls, central peaks, overturned ice, and ejecta. Opportune sites for studying habitats and their ...

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