Research Article| March 01, 1993 Rock-avalanche characteristics in dry climates and the effect of flow into lakes: Insights from mid-Tertiary sedimentary breccias near Artillery Peak, Arizona JOHN C. YARNOLD JOHN C. YARNOLD 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1993) 105 (3): 345–360. https://doi.org/10.1130/0016-7606(1993)105<0345:RACIDC>2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation JOHN C. YARNOLD; Rock-avalanche characteristics in dry climates and the effect of flow into lakes: Insights from mid-Tertiary sedimentary breccias near Artillery Peak, Arizona. GSA Bulletin 1993;; 105 (3): 345–360. doi: https://doi.org/10.1130/0016-7606(1993)105<0345:RACIDC>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Rock-avalanche deposits can be significant components of aggradational sequences formed in dry climates. Features distinguishing such deposits from their closest counterparts, debris-flow deposits, reflect the higher energies and shear strengths associated with rock-avalanche lobes, and their tendency to generate their own matrix through pulverization associated with the failure event.Evaluation of sedimentary breccias in Oligocene-Miocene strata deposited under dry climatic conditions in west-central Arizona indicates that many are of rock-avalanche origin. Some are sufficiently large to have represented large rock avalanches (that is, sturzstroms) at the time of emplacement and display features consistent with descriptions of such lobes. Some rock-avalanche deposits interbedded with lacustrine sediments represent initially subaerial lobes that flowed into lakes. These bodies locally are intruded by substrate-derived injection structures and contaminated by lakebed mud; mud contamination was initially concentrated along the bases of lobes but affected a progressively greater proportion of the flows with increasing subaqueous runout. Contaminated portions of rock-avalanche lobes exhibit features consistent with decreased shear strength, and thoroughly contaminated lobes appear to have transformed into slow-moving, slurry-like flows that experienced internal cycling of debris. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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