A COOL EASTERN PACIFIC OCEAN AT THE CLOSE OF THE LAST INTERGLACIAL PERIOD, ~80,000 YR BP

New high-precision (TIMS) U-series ages of solitary corals from eight marine terrace localities along the U.S. Pacific Coast date to the ~80,000 yr B.P. high stand of sea, late in the last interglacial complex. Activity ratios for Th isotopes are high (88-600; most >200), indicating little inherited daughter Th. Except for Pt. Arena, initial U-isotopic ratios indicate that the ages are very reliable. The span of ages from two localities with multiple corals (see below) suggests that the high sea stand lasted at least 4,000 yr (Green Oaks Creek, n=10) and could have lasted as long as 10,000 yr (San Nicolas Island, n=8). All localities have molluscan faunas that contain several extralimital northern species and lack extralimital southern species. In addition, two localities have molluscan oxygen isotope compositions significantly heavier than modern specimens, indicating water temperatures 1.5 to 3.5°C cooler than present. The combined U-series, faunal and oxygen isotope data suggest a major high sea stand at ~80,000 yr B.P., with cooler-than-modern marine waters, probably heightened by a strengthened California Current

LOCALITY	AGE (ka)	INITIAL 234U/238U
Coquille Point, OR	78.6 ± 0.5	1.1427 ± 0.0018
Point Arena, CA	82.8 ± 0.8	1.1145 ± 0.0041
Green Oaks Crk., CA (youngest)	77.3 ± 0.3	1.1488 ± 0.0020
Green Oaks Crk., CA (oldest)	81.2 ± 0.7	1.1486 ± 0.0025
Point Año Nuevo, CA	75.8 ± 0.4	1.1391 ± 0.0023
Point Santa Cruz, CA	71.5 ± 0.4	1.1511 ± 0.0022
San Nicolas Island, CA (youngest)	76.1 ± 0.4	1.1427 ± 0.0023
San Nicolas Island, CA (oldest)	86.6 ± 0.8	1.1501 ± 0.0026
Palos Verdes Hills, CA	82.7 ± 0.9	1.1541 ± 0.0018
San Pedro, CA	78.5 ± 0.5	1.1437 ± 0.0027