Strontium isotopic composition of estuarine sediments as paleosalinity-paleoclimate indicator

Journal Article · Fri Jan 03 00:00:00 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), Vol. 255:5040; ISSN 0036-8075
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
54 ENVIRONMENTAL SCIENCES
ESTUARIES
ISOTOPE RATIO
MULTI-ELEMENT ANALYSIS
FORAMINIFERA
PALEOCLIMATOLOGY
RIVERS
SALINITY
SAN FRANCISCO BAY
SEAS
SEDIMENTS
STRONTIUM 86
STRONTIUM 87
ALKALINE EARTH ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INVERTEBRATES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MICROORGANISMS
NUCLEI
PACIFIC OCEAN
PALEONTOLOGY
PROTOZOA
RADIOISOTOPES
SARCODINA
STABLE ISOTOPES
STREAMS
STRONTIUM ISOTOPES
SURFACE WATERS
580000* - Geosciences
540310 - Environment
Aquatic- Basic Studies- (1990-)