Variations in the strontium isotopic composition of seawater during the Neogene

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1991)019<0024:VITSIC>2.3.CO;2· OSTI ID:5679800

Hodell, D A; Mueller, P A; Garrido, J R ^[1]

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1. Univ. of Florida, Gainesville (USA)

The authors report 261 strontium isotopic analyses of well-preserved planktonic foraminifers from three Deep Sea Drilling Project Sites (519, 588, and 607). These samples cover the period from 24 Ma to present with an average of approximately one sample per 100 ka. The combination of high sample density and uniformity of analytical procedures has produced a well-defined record of changes in the {sup 87}Sr/{sup 86}Sr of seawater during the Neogene. The record can be viewed as a series of essentially linear segments with slopes ranging from as high as 6{times}10{sup {minus}5}/m.y. to as low as 0/m.y. The times associated with major inflections in the curve do not appear to correspond to simple geologic phenomena such as eustatic cycles, but are probably controlled by a combination of tectonic and climatic factors that influenced the abundance and isotopic composition of terrestrial strontium input to the oceans. The strontium isotopic data are consistent with a progressive increase in the chemical weathering rates of the continents during the Neogene, probably related to repeated glaciations, increased exposure of continents by lowered sea level, and increased continental relief resulting from high rates of tectonic uplift.

• OSTI ID: 5679800
• Journal Information: Geology; (USA), Vol. 19:1; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
SEAWATER
GEOCHEMISTRY
ABUNDANCE
BOREHOLES
CLIMATES
FOSSILS
GEOLOGIC HISTORY
GLACIERS
GROUND UPLIFT
ISOTOPE RATIO
MEASURING METHODS
SAMPLING
SEA LEVEL
STRONTIUM 86
STRONTIUM 87
TECTONICS
TERTIARY PERIOD
VARIATIONS
WEATHERING
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
CAVITIES
CENOZOIC ERA
CHEMISTRY
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEVELS
NUCLEI
OXYGEN COMPOUNDS
RADIOISOTOPES
STABLE ISOTOPES
STRONTIUM ISOTOPES
WATER
580000* - Geosciences