Coastal landsliding and catastrophic sedimentation triggered by Cretaceous-Tertiary bolide impact: A Pacific margin example?

Research Article| August 01, 2002 Coastal landsliding and catastrophic sedimentation triggered by Cretaceous-Tertiary bolide impact: A Pacific margin example? Cathy J. Busby; Cathy J. Busby 1Department of Geological Sciences, University of California, Santa Barbara, California 93106, USA Search for other works by this author on: GSW Google Scholar Grant Yip; Grant Yip 1Department of Geological Sciences, University of California, Santa Barbara, California 93106, USA Search for other works by this author on: GSW Google Scholar Lars Blikra; Lars Blikra 2Geological Survey of Norway, N-7040 Trondheim, Norway Search for other works by this author on: GSW Google Scholar Paul Renne Paul Renne 3Berkeley Geochronology Center, 2453 Ridge Road, Berkeley, California 94709, USA Search for other works by this author on: GSW Google Scholar Geology (2002) 30 (8): 687–690. https://doi.org/10.1130/0091-7613(2002)030<0687:CLACST>2.0.CO;2 Article history received: 25 Oct 2001 rev-recd: 11 Apr 2002 accepted: 16 Apr 2002 first online: 02 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 Cathy J. Busby, Grant Yip, Lars Blikra, Paul Renne; Coastal landsliding and catastrophic sedimentation triggered by Cretaceous-Tertiary bolide impact: A Pacific margin example?. Geology 2002;; 30 (8): 687–690. doi: https://doi.org/10.1130/0091-7613(2002)030<0687:CLACST>2.0.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 SocietyGeology Search Advanced Search Abstract We report here the first-recognized Pacific margin stratigraphic sequence containing evidence for catastrophic landsliding attributed to bolide impact–related seismic shocking at the Cretaceous-Tertiary (K-T) boundary. The K-T boundary is not commonly preserved in stratigraphic sequences of the Pacific margin, but we have discovered it within a coastal paleovalley in Baja California, Mexico (near El Rosario). This 5-km-wide, 15-km-long, and 200-m-deep coastal paleovalley formed by massive gravitational collapses and rapidly filled with coastal (shallow marine and lesser fluvial) gravels and sands, as well as slide sheets of marine mudstone that range from meters to kilometers in length. We infer that seismic shocking caused liquefaction and extremely rapid sedimentation of the gravels and sands, simultaneous with unleashing of slide sheets. Laser-heating 40Ar/39Ar data for biotite, hornblende, and plagioclase (single crystal and bulk step heating) on a 20-m-thick pumice lapilli tuff in the middle of the valley fill give an age of 65.5 ± 0.6 Ma; this is indistinguishable from the age of Haitian tektites dated by the same laboratory. Our new Pacific margin sequence, like many K-T boundary sequences in the Gulf of Mexico–Caribbean region, provides evidence of giant landslides and catastrophic sedimentation 1800 km from the bolide impact site. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.