Preliminary Integrated Chronostratigraphy of the AND-2A Core, ANDRILL Southern McMurdo Sound Project, Antarctica

• Main Authors: Acton, G., Crampton, J., Di Vincenzo, G., Fielding, C. R., Florindo, F., Hannah, M., Harwood, D. M., Ishman, S., Johnson, K., Jovane, L., Levy, R. H., Lum, B., Marcano, M. C., Mukasa, S., Ohneiser, C., Olney, M. P., Riesselman, C., Sagnotti, L., Stefano, C., Strada, E., Taviani, M., Tuzzi, E., Verosub, K. L., Wilson, G. S., Zattin, M., the ANDRIL-SMS Science Team
• Other Authors: Acton, G.; Geology Department, University of California – Davis, One Shields Ave., Davis, CA, 95616 - USA, Crampton, J.; GNS Science, 1 Fairway Drive, PO Box 30308, Lower Hutt - New Zealand, Di Vincenzo, G.; Istituto di Geoscienze e Georisorse, CNR, Via Moruzzi 1, I-56124 Pisa - Italy, Fielding, C. R.; Department of Geoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0340 - USA, Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Hannah, M.; School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 4007 - New Zealand, Harwood, D. M.; Department of Geoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0340 - USA, Ishman, S.; Department of Geology, Southern Illinois University, 1259 Lincoln Drive, Carbondale, IL, 62901 - USA, Johnson, K.; School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, OH, 43210 - USA, Jovane, L.; Geology Department, University of California – Davis, One Shields Ave., Davis, CA, 95616 - USA, Levy, R. H.; ANDRILL Science Management Office, University of Nebraska-Lincoln, Lincoln, NE, 68588-0341 - USA, Lum, B.; Geology Department, University of California – Davis, One Shields Ave., Davis, CA, 95616 - USA, Marcano, M. C.; Dept. of Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109 - USA, Mukasa, S.; Dept. of Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109 - USA, Ohneiser, C.; Department of Geology, University of Otago, PO Box 56, Dunedin - New Zealand, Olney, M. P.; Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL, 33620 - USA, Riesselman, C.; Geological and Environmental Sciences, Stanford University, Braun Hall, Bldg. 320, Stanford, CA, 94305 - USA, Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Stefano, C.; Dept. of Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109 - USA, Strada, E.; Dipartimento di Scienze della Terra, Università di Siena, Via del Laterino 8, I-53100 Siena – Italy, Taviani, M.; CNR, ISMAR - Bologna, Via Gobetti 101, I-40129 Bologna - Italy, Tuzzi, E.; Department of Geoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0340 - USA, Verosub, K. L.; Geology Department, University of California – Davis, One Shields Ave., Davis, CA, 95616 - USA, Wilson, G. S.; Department of Geology, University of Otago, PO Box 56, Dunedin - New Zealand, Zattin, M.; Dip. Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, I-40126 Bologna - Italy, the ANDRIL-SMS Science Team; http://www.andrill.org/projects/sms/team.html, Geology Department, University of California – Davis, One Shields Ave., Davis, CA, 95616 - USA, GNS Science, 1 Fairway Drive, PO Box 30308, Lower Hutt - New Zealand, Istituto di Geoscienze e Georisorse, CNR, Via Moruzzi 1, I-56124 Pisa - Italy, Department of Geoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0340 - USA, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 4007 - New Zealand, Department of Geology, Southern Illinois University, 1259 Lincoln Drive, Carbondale, IL, 62901 - USA, School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, OH, 43210 - USA, ANDRILL Science Management Office, University of Nebraska-Lincoln, Lincoln, NE, 68588-0341 - USA, Dept. of Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109 - USA, Department of Geology, University of Otago, PO Box 56, Dunedin - New Zealand, Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL, 33620 - USA, Geological and Environmental Sciences, Stanford University, Braun Hall, Bldg. 320, Stanford, CA, 94305 - USA, Dipartimento di Scienze della Terra, Università di Siena, Via del Laterino 8, I-53100 Siena – Italy, CNR, ISMAR - Bologna, Via Gobetti 101, I-40129 Bologna - Italy, Dip. Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, I-40126 Bologna - Italy, http://www.andrill.org/projects/sms/team.html
• Format: Article in Journal/Newspaper
• Language: English
• Published: Terra Antartica 2009
• Subjects: ANDRILL; Antarctica; Stratigraphy; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism; McMurdo Sound; Antarc*; Ice Sheet
• Online Access: http://hdl.handle.net/2122/6034

We use all available chronostratigraphic constraints – biostratigraphy, magnetostratigraphy, radioisotopic dates, strontium-isotope stratigraphy, and correlation of compositional and physical properties to well-dated global or regional records – to construct a preliminary age model for ANDRILL SMS Project’s AND-2A drillcore (77°45.488’S, 165°16.605’E, 383.57 m water depth). These diverse chronostratigraphic constraints are consistent with each other and are distributed throughout the 1138.54 m-thick section, resulting in a well-constrained age model. The sedimentary succession comprises a thick early and middle Miocene section below 224.82 mbsf and a condensed middle/late Miocene to Recent section above this. The youngest sediments are Brunhes age (<0.781 Ma), as confirmed by a radioisotopic age of 0.691±0.049 Ma at 10.23 mbsf and the occurrence of sediments that have normal magnetic polarity down to ~31.1 mbsf, which is interpreted to be the Brunhes/Matuyama reversal (0.781 Ma). The upper section is punctuated by disconformities resulting from both discontinuous deposition and periods of extensive erosion typical of sedimentary environments at the margin of a dynamic ice sheet. Additional breaks in the section may be due to the influence of tectonic processes. The age model incorporates several major hiatuses but their precise depths are still somewhat uncertain, as there are a large number of erosional surfaces identified within the stratigraphic section. One or more hiatuses, which represent a total 7 to 8 million years of time missing from the sedimentary record, occur between about 50 mbsf and the base of Lithostratigraphic Unit (LSU) 3 at 122.86 mbsf. Similarly, between about 145 mbsf and the base of LSU 4 at 224.82 mbsf, one or more hiatuses occur on which another 2 to 3 million years of the sedimentary record is missing. Support for the presence of these hiatuses comes from a diatom assemblage that constrains the age of the core from 44 to 50 mbsf to 2.06-2.84 Ma, two radioisotopic dates (11.4 Ma) and ...