Subedifice collapse of an andesitic stratovolcano: The Maitahi Formation, Taranaki Peninsula, New Zealand

Research Article| January 01, 2012 Subedifice collapse of an andesitic stratovolcano: The Maitahi Formation, Taranaki Peninsula, New Zealand David R. Gaylord; David R. Gaylord † 1School of Earth and Environmental Sciences, Washington State University, Webster Physical Sciences Building, Pullman, Washington 99164-2812, USA †E-mail: gaylordd@wsu.edu Search for other works by this author on: GSW Google Scholar Vincent E. Neall Vincent E. Neall 2Institute of Natural Resources, Massey University, Private Bag 11, 222 Palmerston North, New Zealand Search for other works by this author on: GSW Google Scholar Author and Article Information David R. Gaylord † 1School of Earth and Environmental Sciences, Washington State University, Webster Physical Sciences Building, Pullman, Washington 99164-2812, USA Vincent E. Neall 2Institute of Natural Resources, Massey University, Private Bag 11, 222 Palmerston North, New Zealand †E-mail: gaylordd@wsu.edu Publisher: Geological Society of America Received: 30 Jul 2009 Revision Received: 15 Dec 2010 Accepted: 17 Dec 2010 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2012 Geological Society of America GSA Bulletin (2012) 124 (1-2): 181–199. https://doi.org/10.1130/B30141.1 Article history Received: 30 Jul 2009 Revision Received: 15 Dec 2010 Accepted: 17 Dec 2010 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation David R. Gaylord, Vincent E. Neall; Subedifice collapse of an andesitic stratovolcano: The Maitahi Formation, Taranaki Peninsula, New Zealand. GSA Bulletin 2012;; 124 (1-2): 181–199. doi: https://doi.org/10.1130/B30141.1 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 The Maitahi Formation is a large-volume (>7.5 km3) debris-avalanche deposit that resulted from a mid-Pleistocene (ca. 0.24–0.21 Ma) collapse of Pouakai Volcano, Taranaki Peninsula, New Zealand. It is best exposed at intermediate distances (12–14 km) from its source and consists of heterolithologic megaclast-rich and megaclast-poor facies. There are four megaclast and clast types: (1) volcanogenic sedimentary deposits derived from the cone and ring plain; (2) extrusive and intrusive igneous rocks derived primarily from the cone; (3) Pliocene mudstone-rich, subedifice bedrock; and (4) pyroclastic deposits derived from the cone and ring plain. Transport of intact, weakly to moderately lithified, volcanogenic sedimentary and bedrock megaclasts and megaclast domains, tens of meters in diameter, indicates that the W-NW–directed Maitahi debris avalanche was dominantly viscous and nonturbulent. Normally faulted, stratified megaclasts reflect flow dilation, whereas jigsaw-puzzle fractured megaclasts and clasts are evidence for early-stage compression and limited particle-particle and particle-substrate collisions. Folded and elongated megaclasts and clasts and injected interclast matrix reflect the influences of syn- and postavalanche compression, loading, penetrative shear, and pore-fluid overpressures.A significant subedifice bedrock and ring-plain megaclast and clast content distinguishes the Maitahi Formation from all other Taranaki Peninsula debris-avalanche deposits. Coupled with its large volume, the subedifice bedrock content also suggests that the Maitahi Formation originated from a deep-seated edifice collapse, unlike subsequent, and apparently shallower, edifice collapses at the nearby and genetically similar Egmont Volcano. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.