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Passchier, Sandra
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Passchier, Sandra
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- PublicationRestrictedMiddle Miocene to Pliocene History of Antarctica and the Southern Ocean(2008)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Haywood, A. M.; School of Earth & Environment, University of Leeds, Leeds LS2 9JT, UK ;Smellie, J. L.; Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK ;Ashworth, A. C.; Department of Geosciences, North Dakota State University, Fargo, ND 58105-5517, USA ;Cantrill, D. J.; Royal Botanic Gardens Melbourne, Private Bag 2000, Birdwood Avenue, South Yarra, Victoria 3141, Australia ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Hambrey, M. J.; Institute of Geography & Earth Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DB, UK ;Hill, D.; Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK ;Hillenbrand, C.-D.; Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK ;Hunter, S. J.; Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK and School of Earth & Environment, University of Leeds, Leeds LS2 9JT, UK ;Larter, R. D.; Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK ;Lear, C. H.; School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, UK ;Passchier, S.; Department of Earth and Environmental Studies, Mallory Hall 252, Montclair State University, Montclair, NJ 07043, USA ;van de Wal, R.; Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, 3584 Utrecht, The Netherlands; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Siegert, M.; School of GeoSciences, Grant Institute, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JW, UK; This chapter explores the Middle Miocene to Pliocene terrestrial and marine records of Antarctica and the Southern Ocean. The structure of the chapter makes a clear distinction between terrestrial and marine records as well as proximal (on or around Antarctica) and more distal records (Southern Ocean). Particular geographical regions are identified that reflect the areas for which the majority of palaeoenvironmental and palaeoclimatic information exist. Specifically, the chapter addresses the terrestrial sedimentary and fjordal environments of the Transantarctic Mountains and Lambert Glacier region, the terrestrial fossil record of Antarctic climate, terrestrial environments of West Antarctica, and the marine records of the East Antarctic Ice Sheet (EAIS), the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet (APIS), as well as the marine record of the Southern Ocean. Previous and current studies focusing on modelling Middle Miocene to Pliocene climate, environments and ice sheets are discussed.162 32 - PublicationOpen AccessA sedimentological record of early Miocene ice advance and retreat, AND-2A drill hole, McMurdo Sound, Antarctica(2018-08)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ;The lowest 501 m (similar to 1139-638 m) of the AND-2A core from southern Mc-Murdo Sound is the most detailed and complete record of early Miocene sediments in Antarctica and indicates substantial variability in Antarctic ice sheet activity during early Miocene time. There are two main pulses of diamictite accumulation recorded in the core, and three significant intervals with almost no coarse clasts. Each diamictite package comprises several sequences consistent with ice advance-retreat episodes. The oldest phase of diamictite deposition, Composite Sequence 1 (CS1), has evidence for grounded ice at the drill site and has been dated around 20.2-20.1 Ma. It likely coincides with cooling associated with isotope event Mi1aa. This is overlain by a diamictite-free, sandstone-dominated interval, CS2 that includes three coarsening-upward deltaic cycles, is inferred to mark substantial warming, and has an inferred age range between 20.1 and 20.05 Ma. Above this is an interval with variable amounts of diamictite (CS3), with indicators of ice grounding, that is inferred to record ice advance relative to CS2, and is overlain by an similar to 100-m-thick mud-rich interval (CS4) with no sedimentological evidence for direct glacial influence at the drill site (ca. 19.4-18.7 Ma). A third overlying diamictite-rich interval (CS5) overlies an unconformity spanning 18.7-17.8 Ma (coinciding with isotope event Mi1b), and records a return to more ice-influenced conditions at the drill site in late early Miocene time. The overall picture for the early Miocene (spanning the period 20.2-17.35 Ma) is one of ice advance alternating with periods of ice retreat and hence significant global climate fluctuations after the permanent establishment of the Antarctic ice sheet at the Eocene/Oligocene boundary, and preceding the relative warmth of the middle Miocene climatic optimum (ca. 17.5-14.5 Ma). Sedimentary cyclicity in CS1 and CS2 is consistent with similar to 21 k.y. precession but in CS3 the frequency is closer to 100 k.y. (consistent with eccentricity), with a possible change to 20 k.y. precession in CS4. CS5 cyclicity is consistent with obliquity forcing. Provenance data are consistent with local Trans antarctic Mountains glacial activity under precessional control in CS1 and more southerly ice-cap build up under 100 k.y. eccentricity and obliquity control during CS3 and CS5, respectively.77 24 - PublicationRestrictedEarly and middle Miocene Antarctic glacial history from the sedimentary facies distribution in the AND-2A drill hole, Ross Sea, Antarctica(2011-11)
; ; ; ; ; ; ; ;ANDRILL-SMS Science Team, ;Passchier, S.; Department of Earth and Environmental Studies, Montclair State University, Montclair, New Jersey 07043, USA ;Browne, G.; GNS Science, PO Box 30-368, Lower Hutt 5040, New Zealand ;Field, B.; GNS Science, PO Box 30-368, Lower Hutt 5040, New Zealand ;Fielding, C. R.; Department of Earth and Atmospheric Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA ;Krissek, L. A.; School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA ;Panter, K.; Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403, USA ;Pekar, S. F.; School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, New York 11367, USA ;ANDRILL-SMS Science Team,; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ; In 2007, the Antarctic Geological Drilling Program (ANDRILL) drilled 1138.54 m of strata ~10 km off the East Antarctic coast, includ ing an expanded early to middle Miocene succession not previously recovered from the Antarctic continental shelf. Here, we pre sent a facies model, distribution, and paleoclimatic interpretation for the AND-2A drill hole, which enable us, for the fi rst time, to reconstruct periods of early and middle Miocene glacial advance and retreat and paleo environmental changes at an ice-proximal site. Three types of facies associations can be recognized that imply signifi cantly different paleoclimatic interpretations. (1) A diamictite-dominated facies association represents glacially dominated depositional environments, including subglacial environments, with only brief intervals where ice-free coasts existed, and periods when the ice sheet was periodically larger than the modern ice sheet. (2) A stratified diamictite and mudstone facies association includes facies characteristic of open-marine to iceberg-infl uenced depositional environments and is more consistent with a very dynamic ice sheet, with a grounding line south of the modern position. (3) A mudstone-dominated facies association generally lacks diamictites and was produced in a glacially infl uenced hemipelagic depositional environment. Based on the distribution of these facies associations, we can conclude that the Antarctic ice sheets were dynamic, with grounding lines south of the modern location at ca. 20.1–19.6 Ma and ca. 19.3–18.7 Ma and during the Miocene climatic optimum, ca. 17.6–15.4 Ma, with ice-sheet and sea-ice minima at ca. 16.5–16.3 Ma and ca. 15.7–15.6 Ma. While glacial minima at ca. 20.1–19.6 Ma and ca. 19.3–18.7 Ma were characterized by temperate margins, an increased abundance of gravelly facies and diatomaceous siltstone and a lack of meltwater plume deposits suggest a cooler and drier climate with polythermal conditions for the Miocene climatic optimum (ca. 17.6–15.4 Ma). Several periods of major ice growth with a grounding line traversing the drill site are recognized between ca. 20.2 and 17.6 Ma, and after ca. 15.4 Ma, with evidence of cold polar glaciers with ice shelves. The AND-2A core provides proximal evidence that during the middle Miocene climate transition, an ice sheet larger than the modern ice sheet was already present by ca. 14.7 Ma, ~1 m.y. earlier than generally inferred from deep-sea oxygen isotope records. These fi ndings highlight the importance of high-latitude ice-proximal records for the interpretation of far-fi eld proxies across major climate transitions.191 27 - PublicationRestrictedSequence stratigraphy of the ANDRILL AND-2A drillcore, Antarctica: A long-term, ice-proximal record of Early to Mid-Miocene climate, sea-level and glacial dynamism(2011-05-15)
; ; ; ; ; ; ; ; ; ; ;Fielding, C. R.; Department of Earth & Atmospheric Sciences, 214 Bessey Hall, University of Nebraska-Lincoln, NE 68588-0340, USA ;Browne, G. H.; GNS Science, P.O. Box 30368, Lower Hutt, New Zealand ;Field, B.; GNS Science, P.O. Box 30368, Lower Hutt, New Zealand ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Harwood, D. M.; Department of Earth & Atmospheric Sciences, 214 Bessey Hall, University of Nebraska-Lincoln, NE 68588-0340, USA ;Krissek, L. A.; School of Earth Sciences, Ohio State University, 125 South Oval Mall, Columbus, OH 43210, USA ;Levy, R. H.; GNS Science, P.O. Box 30368, Lower Hutt, New Zealand ;Panter, K. S.; Department of Geology, Bowling Green State University, Bowling Green, OH 43403, USA ;Passchier, S.; Department of Earth & Environmental Sciences, Montclair State University, 252 Mallory Hall, 1 Normal Avenue, Montclair, NJ 07043, USA ;Pekar, S. F.; School of Earth & Environmental Sciences, Queen's College, 65-30 Kissena Blvd., Flushing, NY 11367, USA; ; ; ; ; ; ; ; ; Present understanding of Antarctic climate change during the Early to Mid-Miocene, including major cycles of glacial expansion and contraction, relies in large part on stable isotope proxies from deep sea core drilling. Here, we summarize the lithostratigraphy of the ANDRILL Southern McMurdo Sound Project drillcore AND- 2A. This core offers a hitherto unavailable ice-proximal stratigraphic archive from a high-accommodation continental margin setting, and provides clear evidence of repeated fluctuations in climate, ice expansion/ contraction and attendant sea-level change over the period c. 20.2–14.2 Ma, with a more fragmentary record of Late Miocene and Pliocene time. The core is divided into seventy-four high-frequency (fourth- or fifthorder) glacimarine sequences recording repeated advances and retreats of glaciers into and out of the Victoria Land Basin. The section can be resolved into thirteen longer-term, composite (third-order) sequences, which comprise packages of higher frequency sequences that show a consistent stratigraphic stacking pattern (Stratigraphic Motif). The distribution of the six recognized motifs indicates intervals of less and more iceproximal, and temperate to subpolar/polar climate, through the Miocene period. The core demonstrates a dynamic climate regime throughout the Early to Mid-Miocene that may be correlated to some previouslyrecognized events such as the Mid-Miocene Climatic Optimum, and provides a detailed reference point from which to evaluate stable isotope proxy records from the deep-sea.252 39 - PublicationOpen AccessMiocene Glacial Dynamics Recorded by Variations in Magnetic Properties in the ANDRILL‐2A Drill Core(2019-03)
; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ; ;During the 2007 ANtarctic geological DRILLing (ANDRILL) campaign in the Ross Sea, Antarctica, the AND-2A core was recovered through a stratigraphic succession spanning 1,138.54m of Neogene sedimentary rocks that include an expanded early to middle Miocene sequence. The study reported here focuses on the magnetic properties of the interval from 778.63m below sea floor (mbsf) to 1,138.54mbsf, which comprises a time interval spanning 1.5Myr, from 18.7 to 20.2Ma. We recognize three main pulses of increased input of magnetic materials to the drill site between 778.34-903.06, 950.55-995.78, and 1,040-1,103.96mbsf. Trends in the magnetic mineral concentration dependent parameters mirror changes in the proportion of sediments derived from McMurdo Volcanic Group rocks. We suggest that these pulses in magnetic mineral concentration reflect changes in sediment transport processes associated with changing glacial conditions at the drill site that included (1) subglacial and grounding zone proximal settings, (2) hemipelagic and neritic conditions with abundant sediment-rich icebergs, and (3) grounding zone-distal environment that was covered by land-fast multiyear sea ice or a fringing ice shelf. The magnetic minerals record preserved in the AND-2A core supports other data that indicate a highly dynamic and variable coastal environment during the early Miocene, where glaciers retreated inland under warm climatic conditions and advanced beyond the drill site across the continental shelf when cold climate prevailed.152 18