(Appendix 1) Age, Ge/Si ratio, aluminium and opal contents in ODP Sites 175-1081 and 175-1084


Autoria(s): Lin, Hui-Ling; Chen, Chiau-Ju
Cobertura

MEDIAN LATITUDE: -22.566785 * MEDIAN LONGITUDE: 12.173535 * SOUTH-BOUND LATITUDE: -25.513880 * WEST-BOUND LONGITUDE: 11.319300 * NORTH-BOUND LATITUDE: -19.619690 * EAST-BOUND LONGITUDE: 13.027770 * DATE/TIME START: 1997-09-09T02:00:00 * DATE/TIME END: 1997-09-24T03:15:00 * MINIMUM ELEVATION: -1991.9 m * MAXIMUM ELEVATION: -794.1 m

Data(s)

11/08/2002

Resumo

As a result of both culture and sediment core studies, the ratio of germanium (Ge) to silicon (Si) in diatom shells has been proposed as a proxy for monitoring whole-ocean changes in seawater Ge/Si, a ratio affected by changes in continental weathering. However, because of the difficulties of extracting and cleaning diatom frustules from deep-sea sediments, only samples from highly pure diatom oozes in the Antarctic region have been previously analyzed. Here we present data on diatom Ge/Si ratios, (Ge/Si)opal, for the time interval between 3.1 and 1.9 Ma from a mid-latitude, coastal upwelling area where significant terrigenous sediment input complicated the sample processing and analyses. In general, our (Ge/Si)opal values show the same decreasing trend after 2.6 Ma than previously measured in Antarctic sediments (Shemesh et al., 1989. Paleoceanography 4, 221-231), but with a noisier background that may reflect the local imprint of proximal continental input superimposed upon global changes in the ocean reservoir. The time of initiation of large-scale North Hemisphere glaciation at ~2.6 Ma is characterized by a declining pattern of diatom Ge/Si ratios, which could have resulted from a global increase in the input of riverine Si due to enhanced silica weathering and/or equatorward (northward) intrusions of subantarctic waters enriched in silica. High (Ge/Si)opal ratios are associated with high opal contents from the same sediment samples and with warm climate as indicated by depleted benthic foraminiferal d18O values from the North and Equatorial Atlantic. Cold periods signified by enriched benthic d18O values, on the contrary, are associated with lower (Ge/Si)opal ratios. We interpret diatom Ge/Si values to reflect the prevailing weathering state on the continents, with greater chemical weathering during warm and wet periods of the Pliocene and less during cooler and drier intervals.

Formato

text/tab-separated-values, 325 data points

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.744050

doi:10.1594/PANGAEA.744050

Idioma(s)

en

Publicador

PANGAEA

Relação

Lin, Hui-Ling; Chen, Chiau-Ju (2002): A late Pliocene daitom Ge/Si record from the Southeast Atlantic. Marine Geology, 180(1-4), 151-161, doi:10.1016/S0025-3227(01)00211-0

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Palavras-Chave #175-1081A; 175-1084A; AGE; Aluminium; Benguela Current, South Atlantic Ocean; DRILL; Drilling/drill rig; Event label; Germanium/Silica, biogenous opal ratio; Joides Resolution; Leg175; Ocean Drilling Program; ODP; ODP sample designation; Opal, biogenic silica; Sample code/label
Tipo

Dataset