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FORAMINIFERAL EVIDENCE OF HOLOCENE SUBSIDENCE AND FAULT DISPLACEMENTS, COASTAL SOUTH OTAGO, NEW ZEALAND

2007; Cushman Foundation for Foraminiferal Research; Volume: 37; Issue: 4 Linguagem: Inglês

10.2113/gsjfr.37.4.344

1943-264X

Bruce W. Hayward, Hugh R Grenfell, Ashwaq T Sabaa, Katherine E. Southall, W. Roland Gehrels,

Geological and Geochemical Analysis

Research Article| October 01, 2007 FORAMINIFERAL EVIDENCE OF HOLOCENE SUBSIDENCE AND FAULT DISPLACEMENTS, COASTAL SOUTH OTAGO, NEW ZEALAND Bruce W. Hayward; Bruce W. Hayward 4 1Geomarine Research, 49 Swainston Rd, St Johns, Auckland, New Zealand. 4Correspondence author. Email: b.hayward@geomarine.org.nz Search for other works by this author on: GSW Google Scholar Hugh R. Grenfell; Hugh R. Grenfell 1Geomarine Research, 49 Swainston Rd, St Johns, Auckland, New Zealand. Search for other works by this author on: GSW Google Scholar Ashwaq T. Sabaa; Ashwaq T. Sabaa 1Geomarine Research, 49 Swainston Rd, St Johns, Auckland, New Zealand. Search for other works by this author on: GSW Google Scholar Kate E. Southall; Kate E. Southall 2Department of Geography, Trinity College, Dublin, Republic of Ireland. Search for other works by this author on: GSW Google Scholar W. Roland Gehrels W. Roland Gehrels 3School of Geography, University of Plymouth, Plymouth, PL4 8AA, Devon, United Kingdom. Search for other works by this author on: GSW Google Scholar Journal of Foraminiferal Research (2007) 37 (4): 344–359. https://doi.org/10.2113/gsjfr.37.4.344 Article history received: 28 Dec 2006 accepted: 19 Jun 2007 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Bruce W. Hayward, Hugh R. Grenfell, Ashwaq T. Sabaa, Kate E. Southall, W. Roland Gehrels; FORAMINIFERAL EVIDENCE OF HOLOCENE SUBSIDENCE AND FAULT DISPLACEMENTS, COASTAL SOUTH OTAGO, NEW ZEALAND. Journal of Foraminiferal Research 2007;; 37 (4): 344–359. doi: https://doi.org/10.2113/gsjfr.37.4.344 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 SocietyJournal of Foraminiferal Research Search Advanced Search Abstract Foraminiferal assemblages preserved in estuarine sedimentary sequences along the coast of South Otago, New Zealand, provide evidence for three Holocene fault-displacements and associated earthquakes within the 250 km-wide continental collision zone along the Australian-Pacific plate boundary. The modern analogue technique was used to estimate paleotidal elevations of the fossil foraminiferal faunas, based on an analogue set of 334 modern New Zealand faunas (including data from three new intertidal transects taken from the studied estuaries). These elevation estimates provide a record of abrupt changes in tidal elevation, which are inferred to have been produced by vertical displacements on nearby faults. The foraminiferal record in cores (0.75–2.8 m long) from Akatore Estuary identify the previously recognized last rupture (~1100 cal yrs BP) on the Akatore Fault, with ~0.4 m of subsidence on the western side produced by actual downthrow or shaking-related compaction of underlying sediment. The foraminiferal record in cores (1.4–7.0 m long) and in an uplifted terrace section from tidal Catlins Lake provides the first evidence of Holocene fault rupture and major earthquake risk south of the Clutha River mouth. Three displacement events on the Settlement Fault, which forms the eastern margin of Catlins Lake, are recognized. The youngest (~1000 cal yrs BP) resulted in 0.4 m of subsidence (downthrow or compaction) on its west side. The penultimate (~3600 cal yrs BP) resulted in ~1.2 m of uplift of an extensive terrace on the east side of the fault with consequent narrowing of the estuarine entrance and reduced salinity in the tidal lake (recorded by foraminiferal faunas). The earliest event (~5000–4500 cal yrs BP) is recognized by ~1 m of abrupt subsidence on the west (Catlins Lake) side of the fault. Foraminiferal faunas in the upper parts of the majority of cores (from high tidal salt meadows) also document ~0.3 m of sea-level rise within the last 150 years. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.