Strontium isotopic composition of estuarine sediments as paleosalinity-paleoclimate indicator

Journal Article · Fri Jan 03 04:00:00 EST 1992 · Science (Washington, D.C.); (United States)

DOI:https://doi.org/10.1126/science.255.5040.68· OSTI ID:7114331

Ingram, B L ^[1]; Sloan, D ^[2]

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1. Stanford Univ., CA (United States) Univ. of California, Berkeley (United States)
2. Univ. of California, Berkeley (United States)

The strontium isotopic composition of biogenic precipitates that occur in estuarine sediments can be used as proxy indicator of paleosalinity and for assessing precipitation and river discharge rates over thousands of years. In the San Francisco Bay estuary, river water with low {sup 87}Sr/{sup 86}Sr ratio (average, 0.7065) and low Sr concentration (0.13 parts per million) mixes with seawater with a higher {sup 87}Sr/{sup 86}Sr ratio (0.7092) and Sr concentration (7.9 parts per million). The predicted mixing relation between salinity and Sr isotopic composition is confirmed by measurements of modern estuarine surface waters. A paleosalinity record obtained from foraminifera for the ancestral San Francisco Bay during oxygen isotope substage 5e of the last interglacial reflects a global rise and fall of sea level, and short time-scale variations related to fluctuations in discharge rates of the Sacramento and San Joaquin rivers.

• OSTI ID: 7114331
• Journal Information: Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 255:5040; ISSN SCIEA; ISSN 0036-8075
• Country of Publication: United States
• Language: English

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ALKALINE EARTH ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
ELECTRON CAPTURE RADIOISOTOPES
ESTUARIES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
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ISOTOPE RATIO
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MICROORGANISMS
MULTI-ELEMENT ANALYSIS
NUCLEI
PACIFIC OCEAN
PALEOCLIMATOLOGY
PALEONTOLOGY
PROTOZOA
RADIOISOTOPES
RIVERS
SALINITY
SAN FRANCISCO BAY
SARCODINA
SEAS
SEDIMENTS
STABLE ISOTOPES
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STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
SURFACE WATERS