Stratigraphic correlation of Pleistocene California borderland marine carbonate using strontium isotopes

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6720632

Capo, R C ^[1]; Depaolo, D J ^[2]

---

1. Univ. of California, Los Angeles (USA)
2. Univ. of California, Berkeley (USA)

High-precision measurements on carbonate sediments have refined the history of the {sup 87}Sr/{sup 86}Sr ratio in Pleistocene seawater and allowed them to construct a standard {sup 87}Sr/{sup 86}Sr vs. age curve, which the authors have applied to stratigraphic correlations in the California Borderland basins. Foraminifera-nannofossil ooze samples from DSDP (Deep Sea Drilling Project) Site 590 in the Tasman Sea (31{degree}S) were analyzed for {sup 87}Sr/{sup 86}Sr to determine the Sr isotopic ratio of ocean water over the past 2.5 m.y. Modeling suggests that changes in river input associated with large variations in global chemical weathering rates are responsible for the observed variations in the {sup 87}Sr/{sup 86}Sr record during the Pliocene-Pleistocene. From 2.4 m.y. to 0.3 m.y., the {sup 87}Sr/{sup 86}Sr ratio of seawater increased rapidly by 14 {times} 10{sup {minus}5}, which makes this period ideal for high-resolution correlations using the Sr isotope method. Based on their standard seawater curve, strontium isotope analyses of macrofossils and foraminifera from carbonate sections from the Santa Barbara-Ventura and Los Angeles basins indicate that the Bathhouse Beach section of the Santa Barbara Formation was deposited between 0.9 and 0.4 m.y. ago, and in part is syndepositional with western portions of the nearly Pliocene-Middle Pleistocene Pico Formation of the Ventura basin, and with the lithologically similar Lomita Marl of the San Pedro Formation at Palos Verdes.

• OSTI ID: 6720632
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
CALIFORNIA
CENOZOIC ERA
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGY
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NORTH AMERICA
NUCLEI
PLEISTOCENE EPOCH
QUATERNARY PERIOD
RADIOISOTOPES
ROCKS
SEDIMENTARY ROCKS
STABLE ISOTOPES
STRATIGRAPHY
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
USA