Terrigenous sediment supply in the Scotia Sea (Southern Ocean): response to Late Quaternary ice dynamics in Patagonia and on the Antarctic Peninsula

Diekmann, Bernhard; Kuhn, Gerhard; Rachold, Volker; Abelmann, Andrea; Brathauer, Uta; Fütterer, Dieter K; Gersonde, Rainer; Grobe, Hannes

doi:10.1016/s0031-0182(00)00138-3

Cited by 99 publications

(91 citation statements)

References 80 publications

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“…In the northern Scotia Sea, the supply of IRD from the Pacific sector of the Southern Ocean is supplemented by IRD from the southern Andean magmatic belt during glacial times and terminations, when the Patagonian ice fields coalesce and expand to the open ocean . In contrast to East Antarctica, where intense iceberg calving is related to interglacial stages, maximum iceberg calving rates from Patagonia and the Antarctic Peninsula document the rapid disintegration of marine ice masses during climate amelioration associated with glacial terminations and less pronounced during short-term climate perturbations (Hofrnann 1999;Diekmann et al 2000). Patagonian land records are consistent with these findings and moreover suggest interhemispheric teleconnections with northernhemispheric climate dynamics (Lowell et al 1995;Heusser et al 2000;McCulloch et al 2000).…”

Section: Ice-rafted Detritus (Ird)mentioning

confidence: 71%

“…In the Weddell Sea, apart from location PS 1789, higher IRD fluxes are related to interglacial stages (Grobe and Mackensen 1992). Marked IRD fluxes in the Bellingshausen Sea off the Antarctic Peninsula (PS 1565) and in the southern (PS2319) and the northern Scotia Sea (PS2515) coincide with glacial terminations and moreover show small short-term spikes during MIS 3 and MIS 2 (Hofrnann 1999;Diekmann et al 2000). In the Bellingshausen Sea, short-term fluctuations in IRD supply for the last glacial period were also noted by Pudsey and Cammerlenghi (1998) and Cofaigh et al (2001).…”

Section: Ice-rafted Detritus (Ird)mentioning

confidence: 88%

“…It has been suggested that increased detrital fluxes might reflect an increased long-distance supply of air-borne dust from Patagonia due to increased continental aridity and/or enhanced wind strengths of the southern-hemispheric westerlies during glacial times (Martin 1990;Kumar et al 1995). However, this suggestion is not well supported by provenance analyses taking into account the mineralogical and geochemical composition (major and trace elements, neodymium and strontium isotopes) of marine muds (Bareille et al 1994;Diekmann et al 2000;Walter et al 2000). Clues for stronger atmospheric dust fluxes during glacial times actually arise from increased dust concentrations ofPatagonian origin in the ice cores from the East Antarctic ice sheet (Petit et al 1990;Grousset et al 1992).…”

Section: Mass-accumulation Rates Ofterrigenous Sediment (Mart)mentioning

confidence: 99%

“…Magmatic rocks also make up a high proportion ofIRD in the Scotia Sea (Conolly and Ewing 1965;Diekmann et al 2000). In the northern Scotia Sea, the supply of IRD from the Pacific sector of the Southern Ocean is supplemented by IRD from the southern Andean magmatic belt during glacial times and terminations, when the Patagonian ice fields coalesce and expand to the open ocean .…”

Section: Ice-rafted Detritus (Ird)mentioning

confidence: 99%

“…Chlorite originates from the Andean mobile belts of South America and the Antarctic Peninsula distributed by the ACC, with possibly minor aeolian contributions Diekmann et al 2000;Hillenbrand and Ehrmann 2001;Hillenbrand et al 2003). The influence of southern-source water masses on particle advec-tion is well displayed by latitudinal gradients ofkaolinitel chlorite ratios in sea-bottom sediments, with decreasing kaolinite/chlorite ratios from north to south.…”

Section: Modern Clay-mineral Provincesmentioning

confidence: 99%

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Terrigenous Sediment Supply in the Polar to Temperate South Atlantic: Land-Ocean Links of Environmental Changes during the Late Quaternary

Diekmann

Fütterer

Grobe

et al. 2003

The South Atlantic in the Late Quaternary

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Terrigenous sediment parameters in modem sea-bottom samples and sediment cores of the South Atlantic are used to infer variations in detrital sources and modes of terrigenous sediment supply in response to environmental changes through the late Quaternary climate cycles. Massaccumulation rates of terrigenous sediment and fluxes of ice-rafted detritus are discussed in terms of temporal variations in detrital sediment input from land to sea. Grain-size parameters ofterrigenous mud document the intensity of bottom-water circulation, whereas clay-mineral assemblages constrain the sources and marine transport routes of suspended fine-grained particulates, controlled by the modes of sediment input and patterns of ocean circulation. The results suggest low-frequency East Antarctic ice dynamics with dominant lOO-kyr cycles and high rates of Antarctic Bottom Water formation and iceberg discharge during interglacial times. In contrast, the more subpolar ice masses of the Antarctic Peninsula also respond to short-term climate variability with maximum iceberg discharges during glacial terminations related to the rapid disintegration of advanced ice masses. In the northern Scotia Sea, increased sediment supply from southern South America points to extended ice masses in Patagonia during glacial times. In the southeastern South Atlantic, changes in regional ocean circulation are linked to global thermohaline ocean circulation and are in phase with northern-hemispheric processes of ice build-up and associated formation of North Atlantic Deep Water, which decreased during glacial times and permitted a wider extension of southern-source water masses in the study area.

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Section: Ice-rafted Detritus (Ird)mentioning

confidence: 71%

Section: Ice-rafted Detritus (Ird)mentioning

confidence: 88%

Section: Mass-accumulation Rates Ofterrigenous Sediment (Mart)mentioning

confidence: 99%

Section: Ice-rafted Detritus (Ird)mentioning

confidence: 99%

Section: Modern Clay-mineral Provincesmentioning

confidence: 99%

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Terrigenous Sediment Supply in the Polar to Temperate South Atlantic: Land-Ocean Links of Environmental Changes during the Late Quaternary

Diekmann

Fütterer

Grobe

et al. 2003

The South Atlantic in the Late Quaternary

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Glacial reduction of AMOC strength and long-term transition in weathering inputs into the Southern Ocean since the mid-Miocene: Evidence from radiogenic Nd and Hf isotopes

2017

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Combined seawater radiogenic hafnium (Hf) and neodymium (Nd) isotope compositions were extracted from bulk sediment leachates and foraminifera of Site 1088, Ocean Drilling Program Leg 177, 2082 m water depth on the Agulhas Ridge. The new data provide a continuous reconstruction of long‐ and short‐term changes in ocean circulation and continental weathering inputs since the mid‐Miocene. Due to its intermediate water depth, the sediments of this core sensitively recorded changes in admixture of North Atlantic Deep Water to the Antarctic Circumpolar Current as a function of the strength of the Atlantic Meridional Overturning Circulation (AMOC). Nd isotope compositions (εNd) range from −7 to −11 with glacial values generally 1 to 3 units more radiogenic than during the interglacials of the Quaternary. The data reveal episodes of significantly increased AMOC strength during late Miocene and Pliocene warm periods, whereas peak radiogenic εNd values mark a strongly diminished AMOC during the major intensification of Northern Hemisphere Glaciation near 2.8 Ma and in the Pleistocene after 1.5 Ma. In contrast, the Hf isotope compositions (εHf) show an essentially continuous evolution from highly radiogenic values of up to +11 during the Miocene to less radiogenic present‐day values (+2 to +4) during the late Quaternary. The data document a long‐term transition in dominant weathering inputs, where inputs from South America are replaced by those from Southern Africa. Moreover, radiogenic peaks provide evidence for the supply of radiogenic Hf originating from Patagonian rocks to the Atlantic sector of the Southern Ocean via dust inputs.

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Deglacial changes in the strength of deep southern component water and sediment supply at the Argentine continental margin

et al. 2017

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The deep southern component water (SCW), comprising Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW), is a major component of the global oceanic circulation. It has been suggested that the deep Atlantic water mass structure changed significantly during the last glacial/interglacial cycle. However, deep SCW source‐proximal records remain sparse. Here we present three coherent deep SCW paleocurrent records from the deep Argentine continental margin shedding light on deep water circulation and deep SCW flow strength in the Southwest Atlantic since the Last Glacial Maximum (LGM). Based on increased sortable silt values, we propose enhanced deep SCW flow strength from 14 to 10 cal ka B.P. relative to the early deglacial/LGM and the Holocene. We propose a direct influence of deep northern component water (NCW) on deep SCW flow strength due to vertical narrowing of deep SCW spreading, concurrent with a migration of the high‐energetic LCDW/AABW interface occupying our core sites. We suggest a shoaled NCW until 13 cal ka B.P., thereby providing space for deep SCW spreading that resulted in reduced carbonate preservation at our core sites. Increased carbonate content from 13 cal ka B.P. indicates that the NCW expanded changing deep water properties at our core sites in the deep Southwest Atlantic. However, southern sourced terrigenous sediments continued to be deposited at our core sites, suggesting that deep SCW flow was uninterrupted along the Argentine continental margin since the LGM.

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Terrigenous sediment supply in the Scotia Sea (Southern Ocean): response to Late Quaternary ice dynamics in Patagonia and on the Antarctic Peninsula

Cited by 99 publications

References 80 publications

Terrigenous Sediment Supply in the Polar to Temperate South Atlantic: Land-Ocean Links of Environmental Changes during the Late Quaternary

Terrigenous Sediment Supply in the Polar to Temperate South Atlantic: Land-Ocean Links of Environmental Changes during the Late Quaternary

Glacial reduction of AMOC strength and long-term transition in weathering inputs into the Southern Ocean since the mid-Miocene: Evidence from radiogenic Nd and Hf isotopes

Deglacial changes in the strength of deep southern component water and sediment supply at the Argentine continental margin

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