PUMA
Istituto di Scienze Marine     
Panter K., Talarico F., Bessett K., Del Carlo P., Field B., Frank T., Hoffmann S., Kuhn G., Taviani M., Bracciali L., Cornamusini G. Petrologic and Geochemical Composition of the AND-2A Core, ANDRILL Southern McMurdo Sound Project, Antarctica. In: Terra Antartica, vol. 15 (1/2) pp. 1 - 45. Museo Nazionale dell'Antartide 'Felice Ippolito' Sezione Scienze della Terra, UniversitÓ di Siena Via del Laterino 8, 53100 Siena - Italy, 2010.
 
 
Abstract
(English)
The compositional record of the AND-2A drillcore is examined using hetrological, sedimentological, volcanological and geochemical analysis of clasts, sediments and pore waters. Preliminary investigations of basement clasts (granitoids and metasediments) indicate both local and distal sources corresponding to variable ice-volume and ice-flow directions. Low abundance of sedimentary clasts (e.g., arkose, litharenite) suggests reduced contributions from sedimentary covers while intraclasts (e.g., diamictite, conglomerate) attest to intrabasinal reworking. Volcanic material includes pyroclasts (e.g., pumice, scoria), sediments and lava. Primary and reworked tephra layers occur within the Early Miocene interval (1093 to 640 metres below sea floor). The compositions of volcanic clasts reveal a diversity of alkaline types derived from the McMurdo Volcanic Group. Finer-grained sediments (e.g., sandstone, siltstone) show increases in biogenic silica and volcanic glass from 230 to 780 mbsf and higher proportions of terrigenous material ca. 350 to 750 mbsf and below 970 mbsf. Basement clast assemblages suggest a dominant provenance from the Skelton Glacier - Darwin Glacier area and from the Ferrar Glacier - Koettlitz Glacier area. Provenance of sand grains is consistent with clast sources. Thirteen Geochemical Units are established based on compositional trends derived from continuous XRF scanning. High values of Fe and Ti indicate terrigenous and volcanic sources, whereas high Ca values signify either biogenic or diagenic sources. Highly alkaline and saline pore waters were produced by chemical exchange with glass at moderately elevated temperatures.
URL: http://www.earth-prints.org/bitstream/2122/5825/1/TA_PP_Panter%20et%20al%202009.pdf
Subject AND-2A Core
ANDRILL
McMurdo Sound
Antarctica


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