Grain size analysis and sedimentation rates of ODP Hole 175-1085A off the Namibian coast

Autoria(s): Roters, Bastian; Henrich, Rüdiger
Cobertura

LATITUDE: -29.374410 * LONGITUDE: 13.990110 * DATE/TIME START: 1997-09-26T00:15:00 * DATE/TIME END: 1997-09-29T18:15:00
Data(s)

07/06/2010
Resumo

Sediments from the ODP Site 1085A were studied to investigate the impacts of global cooling in the Middle and Late Miocene on the climate in Southwestern Africa. The size composition of the sediment was analysed emphasising the silt fraction. A comparison with the modern grain size distribution and suitable transport processes made it possible to assign specific transport processes to the grain size composition. Three processes are considered for transport of terrigeneous silt: while there was no evidence found for (1) transport by ocean currents, the analyses showed signals of (2) wind transport indicating dry conditions associated with a cool climate and (3) fluvial transport that points to humid and warm conditions. Three climatic phases were defined. The first phase from 13.8 to 11.8 Myr reveals a stable humid climate in Southwest Africa independent of the Antarctic glaciations. During the second phase from 11.8 to 10.4 Myr the regional climate cooled considerably but was not drier. Additionally, the climate during this phase reacted to the Antarctic glaciations. This cooling-trend continued during phase 3 from 10.4 to 9.0 Myr with a significant increase in dust input, pointing to overall drier conditions. However, fluvial transport still remained as the main source.
Formato

application/zip, 6 datasets
Identificador

https://doi.pangaea.de/10.1594/PANGAEA.738695

doi:10.1594/PANGAEA.738695
Idioma(s)

en
Publicador

PANGAEA
Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted
Fonte

Supplement to: Roters, Bastian; Henrich, Rüdiger (2010): The middle to late Miocene climatic development of Southwest Africa derived from the sedimentological record of ODP Site 1085A. International Journal of Earth Sciences, 99(2), 459-471, doi:10.1007/s00531-008-0398-9
Palavras-Chave #<2 µm, >9 phi; >63 µm; 175-1085A; 3.9-4.0 phi; 4.0-4.1 phi; 4.1-4.2 phi; 4.2-4.3 phi; 4.3-4.4 phi; 4.4-4.5 phi; 4.5-4.6 phi; 4.6-4.7 phi; 4.7-4.8 phi; 4.8-4.9 phi; 4.9-5.0 phi; 5.0-5.1 phi; 5.1-5.2 phi; 5.2-5.3 phi; 5.3-5.4 phi; 5.4-5.5 phi; 5.5-5.6 phi; 5.6-5.7 phi; 5.7-5.8 phi; 5.8-5.9 phi; 5.9-6.0 phi; 6.0-6.1 phi; 6.1-6.2 phi; 6.2-6.3 phi; 6.3-6.4 phi; 6.4-6.5 phi; 6.5-6.6 phi; 6.6-6.7 phi; 6.7-6.8 phi; 6.8-6.9 phi; 6.9-7.0 phi; 63-2 µm; 7.0-7.1 phi; 7.1-7.2 phi; 7.2-7.3 phi; 7.3-7.4 phi; 7.4-7.5 phi; 7.5-7.6 phi; 7.6-7.7 phi; 7.7-7.8 phi; 7.8-7.9 phi; 7.9-8.0 phi; 8.0-8.1 phi; 8.1-8.2 phi; 8.2-8.3 phi; 8.3-8.4 phi; 8.4-8.5 phi; 8.5-8.6 phi; 8.6-8.7 phi; 8.7-8.8 phi; 8.8-8.9 phi; 8.9-9.0 phi; Acc rate <2 µm; Acc rate <63 µm; Acc rate CaCO3; Accumulation rate, < 63 µm; Accumulation rate, calcium carbonate; Accumulation rate, clay < 2 µm; Age; AGE; Atterberg settling tubes; Benguela Current, South Atlantic Ocean; CaCO3; Calcium carbonate; Calculated, CaCO3=(TC-TOC)*8.333; Calculated, see reference(s); Carbon, organic, total; carbonate; Depth; Depth, composite; DEPTH, sediment/rock; Depth comp; DRILL; Drilling/drill rig; Element analyser CS, LECO CS-200; Grain size, mean; Grain size, SEDIGRAPH 5100; Grain size, sieving; gs mean; Intercore correlation; Joides Resolution; Leg175; LSR bulk; LSR calcareous; LSR terrigeneous; MAR calcareous clay; MAR calcareous silt; MAR terrigeneous clay; MAR terrigeneous silt; MAR TOC bulk; Ocean Drilling Program; ODP; ODP sample designation; Sample code/label; Sedimentation rate; Sed rate; see reference(s); Size fraction < 0.002 mm, > 9 phi, clay; Size fraction > 0.063 mm, sand; Size fraction 0.063-0.002 mm, silt; Size fraction 10.309-9.618 µm, 6.6-6.7 phi; Size fraction 11.049-10.309 µm, 6.5-6.6 phi; Size fraction 11.842-11.049 µm, 6.4-6.5 phi; Size fraction 12.691-11.842 µm, 6.3-6.4 phi; Size fraction 13.602-12.691 µm, 6.2-6.3 phi; Size fraction 14.579-13.602 µm, 6.1-6.2 phi; Size fraction 15.625-14.579 µm, 6.0-6.1 phi; Size fraction 16.746-15.625 µm, 5.9-6.0 phi; Size fraction 17.948-16.746 µm, 5.8-5.9 phi; Size fraction 19.237-17.948 µm, 5.7-5.8 phi; Size fraction 2.093-1.953 µm, 8.9-9.0 phi; Size fraction 2.244-2.093 µm, 8.8-8.9 phi; Size fraction 2.405-2.244 µm, 8.7-8.8 phi; Size fraction 2.577-2.405 µm, 8.6-8.7 phi; Size fraction 2.762-2.577 µm, 8.5-8.6 phi; Size fraction 2.960-2.762 µm, 8.4-8.5 phi; Size fraction 20.617-19.237 µm, 5.6-5.7 phi; Size fraction 22.097-20.617 µm, 5.5-5.6 phi; Size fraction 23.683-22.097 µm, 5.4-5.5 phi; Size fraction 25.383-23.683 µm, 5.3-5.4 phi; Size fraction 27.205-25.383 µm, 5.2-5.3 phi; Size fraction 29.157-27.205 µm, 5.1-5.2 phi; Size fraction 3.173-2.960 µm, 8.3-8.4 phi; Size fraction 3.401-3.173 µm, 8.2-8.3 phi; Size fraction 3.645-3.401 µm, 8.1-8.2 phi; Size fraction 3.906-3.645 µm, 8.0-8.1 phi; Size fraction 31.250-29.157 µm, 5.0-5.1 phi; Size fraction 33.493-31.250 µm, 4.9-5.0 phi; Size fraction 35.897-33.493 µm, 4.8-4.9 phi; Size fraction 38.473-35.897 µm, 4.7-4.8 phi; Size fraction 4.187-3.906 µm, 7.9-8.0 phi; Size fraction 4.487-4.187 µm, 7.8-7.9 phi; Size fraction 4.809-4.487 µm, 7.7-7.8 phi; Size fraction 41.235-38.473 µm, 4.6-4.7 phi; Size fraction 44.194-41.235 µm, 4.5-4.6 phi; Size fraction 47.366-44.194 µm, 4.4-4.5 phi; Size fraction 5.154-4.809 µm, 7.6-7.7 phi; Size fraction 5.524-5.154 µm, 7.5-7.6 phi; Size fraction 5.921-5.524 µm, 7.4-7.5 phi; Size fraction 50.766-47.366 µm, 4.3-4.4 phi; Size fraction 54.409-50.766 µm, 4.2-4.3 phi; Size fraction 58.315-54.409 µm, 4.1-4.2 phi; Size fraction 6.346-5.921 µm, 7.3-7.4 phi; Size fraction 6.801-6.346 µm, 7.2-7.3 phi; Size fraction 62.500-58.315 µm, 4.0-4.1 phi; Size fraction 66.986-62.500 µm, 3.9-4.0 phi; Size fraction 7.289-6.801 µm, 7.1-7.2 phi; Size fraction 7.813-7.289 µm, 7.0-7.1 phi; Size fraction 8.373-7.813 µm, 6.9-7.0 phi; Size fraction 8.974-8.373 µm, 6.8-6.9 phi; Size fraction 9.618-8.974 µm, 6.7-6.8 phi; terrigeneous; TOC; Total carbonate bulk fraction; Total carbonate clay fraction; Total carbonate sand fraction; Total carbonate silt fraction; Total organic carbon bulk fraction
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