A new ice core (TALDICE) drilled at Talos Dome (East Antarctica, Ross Sea sector) preserves a ca. 250 ka long record of palaeoclimate and atmospheric history. We investigate dust variability and provenance at the site during glacial periods and the Holocene through the Sr–Nd isotopic composition of ice core dust and potential source areas (PSA). We provide new isotopic data on dust sources from Victoria Land such as regoliths, glacial drifts, aeolian sands and beach deposits. Some of these sources are located at high altitude and are known to have been ice free throughout the Pleistocene. The major features of the TALDICE dust record are very similar to those from central East Antarctica. During glacial times, South America was the dominant dust supplier for Talos Dome as well as for the entire East Antarctic plateau. Conversely, during the Holocene the principal input of mineral dust at Talos Dome probably derives from proximal sources which are the ice-free areas of northern Victoria Land, located at similar altitude with respect to the drilling site. Atmospheric mobilisation of dust from these neighbouring areas and transport inland to Talos Dome can be ultimately associated with advection of maritime air masses from the Pacific/Ross Sea region

International audienceAeolian mineral dust archived in Antarctic ice cores represents a key proxy for Quaternary climate evolution. The longest and most detailed dust and climate sequences from polar ice are provided today by the Vostok and by the EPICA-Dome C (EDC) ice cores. Here we investigate the geographic provenance of dust windborne to East Antarctica during Early and Middle Pleistocene glacial ages using strontium and neodymium isotopes as tracers. The isotopic signature of Antarctic dust points towards a dominant South American origin during Marine Isotopic Stage (MIS) 8, 10, 12, and back to MIS 16 and 20 as deduced from EDC core. Data provide evidence for a persistent overall westerly circulation pattern allowing efficient transfer of dust from South America to the interior of Antarctica over the last 800 kyr. Some small but significant dissimilarity between old and recent glacial ages suggests a slightly reduced Patagonian contribution during ancient glaciations

No abstract

ISI Document Delivery No.: 956AU Times Cited: 14 Cited Reference Count: 45 Cited References: Alibo DS, 1999, GEOCHIM COSMOCHIM AC, V63, P363, DOI 10.1016/S0016-7037(98)00279-8 Bishop J., METHODS IN PRESS Bishop JKB, 2008, DEEP-SEA RES PT I, V55, P1684, DOI 10.1016/j.dsr.2008.07.012 Chu ZY, 2009, J ANAL ATOM SPECTROM, V24, P1534, DOI 10.1039/b904047a COLLIER R, 1984, PROG OCEANOGR, V13, P113, DOI 10.1016/0079-6611(84)90008-9 Cullen JT, 1999, MAR CHEM, V67, P233, DOI 10.1016/S0304-4203(99)00060-2 DEPAOLO DJ, 1977, GEOPHYS RES LETT, V4, P465, DOI 10.1029/GL004i010p00465 Dodson RW, 1936, J AM CHEM SOC, V58, P2573, DOI 10.1021/ja01303a058 ELDERFIELD H, 1982, NATURE, V296, P214, DOI 10.1038/296214a0 EUGSTER O, 1970, J GEOPHYS RES, V75, P2753, DOI 10.1029/JB075i014p02753 GEOTRACES Planning Group, 2006, GEOTRACES SCI PLAN Goldstein S.L., 2003, TREATISE GEOCHEMISTR, P453, DOI DOI 10.1016/B0-08-043751-6/06179-X Halliday A. N., 2000, INORGANIC MASS SPECT, P291 Harvey J, 2009, CHEM GEOL, V258, P251, DOI 10.1016/j.chemgeo.2008.10.024 HOOKER PJ, 1975, CHEM GEOL, V16, P189, DOI 10.1016/0009-2541(75)90027-3 JACOBSEN SB, 1980, EARTH PLANET SC LETT, V50, P139, DOI 10.1016/0012-821X(80)90125-9 JEANDEL C, 1995, GEOCHIM COSMOCHIM AC, V59, P535, DOI 10.1016/0016-7037(94)00367-U Lacan F, 2005, EARTH PLANET SC LETT, V232, P245, DOI 10.1016/j.epsl.2005.01.004 LANDING WM, 1991, GEOPH MONOG SERIES, V63, P263 Li CF, 2007, INT J MASS SPECTROM, V266, P34, DOI 10.1016/j.ijms.2007.06.013 Lugmair G.W., 1975, P LUNAR PLANET SCI C, P1419 LUGMAIR GW, 1983, SCIENCE, V222, P1015, DOI 10.1126/science.222.4627.1015 Maiti K., 2012, 234 INTERCALIBRATION NANCE WB, 1976, GEOCHIM COSMOCHIM AC, V40, P1539, DOI 10.1016/0016-7037(76)90093-4 ONIONS RK, 1977, EARTH PLANET SC LETT, V34, P13, DOI 10.1016/0012-821X(77)90100-5 ONIONS RK, 1978, NATURE, V273, P435, DOI 10.1038/273435a0 Pahnke K, 2012, LIMNOL OCEANOGR-METH, V10, P252, DOI 10.4319/lom.2012.10.252 PIEPGRAS DJ, 1992, GEOCHIM COSMOCHIM AC, V56, P1851, DOI 10.1016/0016-7037(92)90315-A PIEPGRAS DJ, 1987, GEOCHIM COSMOCHIM AC, V51, P1257, DOI 10.1016/0016-7037(87)90217-1 PIEPGRAS DJ, 1979, EARTH PLANET SC LETT, V45, P223, DOI 10.1016/0012-821X(79)90125-0 PIEPGRAS DJ, 1980, EARTH PLANET SC LETT, V50, P128, DOI 10.1016/0012-821X(80)90124-7 PIEPGRAS DJ, 1988, GEOCHIM COSMOCHIM AC, V52, P1373, DOI 10.1016/0016-7037(88)90208-6 Pin C, 1997, ANAL CHIM ACTA, V339, P79, DOI 10.1016/S0003-2670(96)00499-0 RICHARD P, 1976, EARTH PLANET SC LETT, V31, P269, DOI 10.1016/0012-821X(76)90219-3 SHABANI MB, 1992, ANAL CHEM, V64, P737, DOI 10.1021/ac00031a008 STORDAL MC, 1986, EARTH PLANET SC LETT, V77, P259, DOI 10.1016/0012-821X(86)90138-X Tachikawa K, 2003, J GEOPHYS RES-OCEANS, V108, DOI 10.1029/1999JC000285 Tanaka T, 2000, CHEM GEOL, V168, P279, DOI 10.1016/S0009-2541(00)00198-4 THIRLWALL MF, 1991, CHEM GEOL, V94, P85, DOI 10.1016/0168-9622(91)90002-E THIRLWALL MF, 1991, CHEM GEOL, V94, P13, DOI 10.1016/0168-9622(91)90036-V Vance D, 2004, PALEOCEANOGRAPHY, V19, DOI 10.1029/2003PA000957 Vance D, 2002, CHEM GEOL, V185, P227, D...

Evidence is presented here from the northern Scandinavian Caledonides for development of an extensional basin of Ashgill to Mid Llandovery age along the Baltoscandian margin immediately prior to Baltica–Laurentia collision. U/Pb multigrain and ion microprobe zircon dating of plagiogranites in the Halti Igneous Complex complement previous baddeleyite and zircon dating of a dolerite dyke, and zircon dating of anatectic granite; they demonstrate that this dunite, troctolite, gabbro, sheeted‐dyke complex ranges in age from c. 445 to 435 Ma. The dolerite dykes intruded and melted arkoses of inferred Neoproterozoic age. This evidence, taken together with previous documentation of ophiolites (Solund–Stavfjord), ophiolite‐like associations (Sulitjelma Igneous Complex) and several other mafic suites (e.g. Råna, Artfjället) of Ashgill to Llandovery age further south in the northern Scandinavian Caledonides, implies that Scandian collisional orogeny along this nearly 2000‐km‐long mountain belt was immediately preceeded by development of short‐lived marginal basins. The latter developed during the final closure of the Iapetus Ocean and are inferred to be of back‐arc origin, some (perhaps all) related to E‐dipping subduction. Collision of the continents at c. 435 Ma is inferred to have induced a flip in subduction polarity, leading to underthrusting of Laurentia by Baltica.

No abstract

No abstract

No abstract