Pollen analyses of sediments from Holes 1019C, 1019E, 1020C, and 1020D as well as piston Core EW9504-17 provide
continuous, chronostratigraphically controlled proxy vegetation and climate data for coastal northwest North America for the
last ~500 k.y. Systematic changes in the representation of the diagnostic components of northern California plant assemblages...
Sediments from five Leg 167 drill sites and three piston cores were analyzed for C[subscript ORG] and CaCO₃. Oxygen isotope stratigraphy on benthic foraminifers was used to assign age models to these sedimentary records. We find that the northern and central California margin is characterized by k.y.-scale events that can...
Ocean Drilling Program (ODP) Leg 202 has opened a new window
into understanding late Paleogene and Neogene global environmental
change by providing high-quality sediment sequences from a previously
unsampled region, the eastern South Pacific. Eleven sites (1232–
1242) that record variations on timescales ranging from decades to tens
of millions...
Multiproxy geologic records of δ18O and Mg/Ca in fossil foraminifera from sediments under the Eastern Pacific Warm Pool (EPWP) region west of Central America document variations in upper ocean temperature, pycnocline strength, and salinity (i.e., net precipitation) over the past 30 kyr. Although evident in the paleotemperature record, there is...
The stable isotopic signature of dissolved inorganic carbon (δ¹³CDIC) in the northeast Pacific Ocean is lower in near-surface waters by 1.1‰ relative to values predicted from global oceanic trends of δ¹³CDIC versus nutrients. A combination of anthropogenic carbon uptake from the atmosphere and thermodynamic, air-sea gas exchange processes in different...
The isotopic composition of the dissolved inorganic carbon (DIC) collected at sites of active methane discharge on Hydrate Ridge, Oregon, reveals anaerobic methane oxidation mediated by bacteria, with δ13CDIC reaching values as low as –48‰ in the upper 4 cm of the sediment. In spite of the high sulfide levels...
Planktonic foraminiferal faunas of the southeast Pacific indicate that sea surface temperatures (SST) have
varied by as much as 8–10°C in the Peru Current, and by ~5–7°C along the equator, over the past 150,000 years.
Changes in SST at times such as the Last Glacial Maximum reflect incursion of high-latitude...
In order to quantify changes in export production and carbonate dissolution over the past 1 Myr in the
central equatorial Pacific Ocean we analyzed Ba, P, Al, Ti, and Ca in 1106 samples from five piston cores gathered from
5°S to 4°N at 140°W. We focused on Ba/Ti, Al/Ti, and...
Application of the ²³⁰Th normalization method to estimate sediment burial fluxes in six cores from the
eastern equatorial Pacific (EEP) reveals that bulk sediment and organic carbon fluxes display a coherent regional
pattern during the Holocene that is consistent with modern oceanographic conditions, in contrast with estimates
of bulk mass...
Mg/Ca ratios in planktonic foraminifera reflect calcification temperatures and are thus useful for sea
surface temperature (SST) reconstructions. Despite the obvious utility of this paleoceanographic tracer,
problems of dissolution, gametogenic calcification, and contaminant phases have thus far limited
confidence in Mg/Ca-based reconstructions. Here we show strong evidence of Mg heterogeneity...