Nd, Sr and Pb isotopes and clay minerals in sediment cores from the Gulf of Cadiz and the Portuguese margin


Autoria(s): Stumpf, Roland; Frank, Martin; Schönfeld, Joachim; Haley, Brian A
Cobertura

MEDIAN LATITUDE: 37.716333 * MEDIAN LONGITUDE: -8.929444 * SOUTH-BOUND LATITUDE: 36.380000 * WEST-BOUND LONGITUDE: -10.680000 * NORTH-BOUND LATITUDE: 39.040000 * EAST-BOUND LONGITUDE: -7.071667 * DATE/TIME START: 1997-04-24T14:30:00 * DATE/TIME END: 1997-05-04T18:14:00

Data(s)

18/01/2011

Resumo

The assemblages of marine sediments on the SW Iberian shelf have been controlled by contributions from distinct sources, which have varied in response to environmental changes since the Last Glacial Maximum (LGM). The rapid, decadal scale Mediterranean overturning circulation permits mixing of suspended particles from the entire Mediterranean Sea. They are entrained into the suspended particulate matter (SPM) carried by Mediterranean Outflow Water (MOW), which enters the eastern North Atlantic through the Strait of Gibraltar and spreads at intermediate depths in the Gulf of Cadiz and along the Portuguese continental margin. Other major sediment sources that have contributed to the characteristics and budget of SPM along the flow path of MOW on the SW Iberian shelf are North African dust and river-transported particles from the Iberian Peninsula. To reconstruct climate- and circulation-driven changes in the supply of sediments over the past ~23000 cal yr B.P., radiogenic Nd, Sr and Pb isotope records of the clay-size sediment fraction were obtained from one gravity core in the Gulf of Cadiz (577 m water depth) and from two gravity cores on the Portuguese shelf (1745 m, 1974 m water depth). These records are supplemented by time series analyses of clay mineral abundances from the same set of samples. Contrary to expectations, the transition from the LGM to the Holocene was not accompanied by strong changes in sediment provenance or transport, whereas Heinrich Event 1 (H1) and the African Humid Period (AHP) were marked by significantly different isotopic signatures reflecting changes in source contributions caused by supply of ice rafted material originating from the North American craton during H1 and diminished supply of Saharan dust during the AHP. The data also reveal that the timing of variations in the clay mineral abundances was decoupled from that of the radiogenic isotope signatures.

Formato

application/zip, 2 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.774225

doi:10.1594/PANGAEA.774225

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Stumpf, Roland; Frank, Martin; Schönfeld, Joachim; Haley, Brian A (2011): Climatically driven changes in sediment supply on the SW Iberian shelf since the Last Glacial Maximum. Earth and Planetary Science Letters, 312(1-2), 80-90, doi:10.1016/j.epsl.2011.10.002

Palavras-Chave #206Pb/204Pb; 207Pb/204Pb; 208Pb/204Pb; 2 sigma error = ± 0.00004; 2 sigma error = ±0.005; 2 sigma error = ±0.015; 2 sigma error = ±0.35; 87Sr/86Sr; Age; AGE; Chl; Chlorite; Depth; DEPTH, sediment/rock; e-Nd; epsilon-Neodymium; Event; Finnigan TRITON thermal ionization mass spectrometer (TIMS); Gravity corer (Kiel type); Ill; Illite; Kaolinite; Kln; Lead 206/Lead 204 ratio; Lead 207/Lead 204 ratio; Lead 208/Lead 204 ratio; M39/1; M39/1_08-3; M39/1_36-4; M39/1_58-2; M39008-3; M39058-2; Meteor (1986); Multi-collector inductively coupled plasma - mass spectrometer (MC-ICP-MS); SL; Sme; Smectite; Strontium 87/Strontium 86 ratio; X-ray diffraction, clay fraction
Tipo

Dataset