Variations in the strontium isotopic composition of seawater during the Neogene

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doi: 10.1130/0091-7613(1991)019<0024:VITSIC>2.3.CO;2
Author(s): Hodell, David A.; Mueller, Paul A.; Garrido, Jose R.
Author Affiliation(s): Primary:
Univ. Fla., Dep. Geol., Gainesville, FL, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 19(1), p.24-27. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 37 refs.; illus. incl. 261 anal., 5 tables
Summary: We 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 87Sr/86Sr 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 x 10-5/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.
Year of Publication: 1991
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Atlantic Ocean; Biochemistry; Cenozoic; Chemical weathering; DSDP Site 519; DSDP Site 588; DSDP Site 607; Deep Sea Drilling Project; Foraminifera; Geochemistry; IPOD; Invertebrata; Isotopes; Leg 73; Leg 90; Leg 94; Metals; Microfossils; Neogene; Neotectonics; Oceanography; Pacific Ocean; Paleo-oceanography; Planktonic taxa; Protista; Rates; Sea water; Sr-87/Sr-86; Stable isotopes; Stratigraphy; Strontium; Tectonics; Tertiary; Uplifts; Weathering
Coordinates: S260813 S260811 W0113958 W0113959
S260642 S260642 E1611336 E1611336
N410004 N410005 W0325726 W0325727
Record ID: 1991006640
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