Flexural controls on late Neogene basin evolution in souther

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TitleFlexural controls on late Neogene basin evolution in southern McMurdo Sound, AntarcticaAbstractThe basins of southern McMurdo Sound have evolved under the influence of lithospheric flexure induced by the loads of the Erebus Volcanic Province. To characterise these basins, it is important to investigate the lithosphereÅ› flexural properties, and estimate their influence on basin architecture and evolution. Seismic and gravity data are used to constrain 3D forward modelling of the progressive development of accommodation space within the flexural basins. Elastic plate flexure was calculated for a range of effective elastic thicknesses (T e) from 0.5 to 25km using a spectral method. Models with low, but nonzero, T e values (2km<T e<5km) produce the best fit to the gravity data, although uncertainty is high due to inaccuracies in the Digital Elevation Model. The slopes of flexural horizons revealed in seismic reflection lines are consistent with this, indicating a T e of 2km to 5km, although the depths to these horizons are not consistent, perhaps due to a northwards slope, or step, in the pre-flexural surface. These results indicate that the lithospheric strength of southern McMurdo Sound is significantly less than estimates of the regional average (T e Â 20km). This low strength may reflect the weakening effects of the Terror Rift, and perhaps also the Discovery Accommodation Zone, a region of major transverse faulting. A low T e model (T e=3) for southern McMurdo Sound predicts the development of two discrete flexural depressions, each 2-2.5km deep. The predicted stratigraphy of the northern basin reflects flexure due to Ross Island, predominantly erupted since ca. 1.8Ma. The predicted stratigraphy of the southern basin reflects more gradual flexure from ca. 10Ma to ca. 2Ma, due to the more dispersed volcanoes of the Discovery subprovince. Collectively, these two basins have the potential to preserve a remarkable stratigraphic record of Antarctic climate change through the late Neogene. Copyright 2011 Elsevier B.V.AcknowledgementsLogistic support for gravity data collection was provided by Antarctica New Zealand as part of ANDRILL site survey events K114 and K001. Financial support for the research was supplied by New Zealand Foundation for Research contracts UOOX0207 and C05X0410 and by the University of Otago Research Committee. We thank all members of the ANDRILL site survey field teams for their assistance in the field gravity data collection programme. The constructive comments of the reviewers helped improve the manuscript and are greatly appreciated.

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1st AuthorAitken, A.AuthorAitken, A.Wilson, G.Jordan, T.Tinto, K.Blakemore, H.Year2012JournalGlobal and Planetary ChangeVolume80-81Pages99-112DOI10.1016/j.gloplacha.2011.08.003URLhttps://www.scopus.com/inward/recor.....d0d3c0a5b07ea4b3479a01e02KeywordsAccommodation spaceAccommodation zoneAntarctic climateAntarcticaBasin evolutionBest fitDigital elevation modelElastic plateFlexural basinsFlexural propertiesFlexureForward modellingGravity dataLate NeogeneLithosphericLithospheric flexureNeo genesNorthern basinsSeismic reflectionsSpectral methodsStratigraphic recordsVolcanic loadWeakening effect, Climate changeGravitationSeismologySpectroscopyStratigraphyVolcanoes, Three dimensional, basin evolutiondigital elevation modelflexuregravity fieldlithospheric structureNeogeneseismic dataseismic reflectionstratigraphythree-dimensional modelingvolcanic eruption, AntarcticaEast AntarcticaMcMurdo Sound, rank5Author KeywordsBasin evolutionFlexureMcMurdo SoundNeogeneVolcanic load

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TypeArticleCitationAitken, A., Wilson, G., Jordan, T., Tinto, K. and Blakemore, H. (2012). Flexural controls on late Neogene basin evolution in southern McMurdo Sound, Antarctica. Global and Planetary Change, 80-81: 99-112