Late Quaternary Sediment of the Panama Basin: Sedimentation Rates, Periodicities, and Controls of Carbonate and Opal Accumulation

Abstract

Assuming a constant rate of quartz accumulation for deep-sea sediment core Y69-106P, from the Panama Basin, I have estimated the age of samples from the core and have constructed a curve for sedimentation-rate versus time. Stratigraphic controls for the calculated time scale include three C 14 measurements, the extinction of the radiolarian Stylatractus universus, correlation with oxygen-isotope curves from other dated cores, and an Ar 40 /Ar 39 age determination.The model sedimentation rates, when combined with data on mineralogic composition, allow the determination of accumulation rates for CaC0 3 , opaline Si0 2 , and remaining "detritus." Fluctuations in CaC0 3 accumulation rates over time correlate with variations in oxygen-isotope ratios in biogenous carbonate from two other equatorial Pacific cores; high oxygen-isotope ratios correlate with high CaC0 3 accumulation rates. Opaline Si0 2 accumulation rates reflect changes in the dominance of different radiolarian fossil groups, changes which can be related to surface circulation in the Panama Basin.Spectral analysis of the accumulation rate of CaC0 3 in core Y69-106P and of the oxygen-isotope record of core V28-238 indicates a 23,000-yr periodicity. Spectral analysis of the opal accumulation rate suggests a 100,000-yr periodicity, which is an important frequency in the oxygen-isotope record. Both these periodicities are close to those found in fluctuations in the Earth's orbital parameters. The eccentricity of the orbit fluctuates with an average period of 98,000 yr, and the precession of the equinoxes changes with a period of 22,000 yr.

Metalliferous-sediment deposition in time and space: East Pacific Rise and Bauer Basin, northern Nazca plate

“…Even in these cores, however, this factor does not change monotonically with depth. Such a pattern is suggestive of glacial-interglacial changes in surface biologic productivity (Pisias, 1976) which our sampling interval cannot fully resolve.…”

Evolution of marine sedimentation in the Bering Sea since the Pliocene

“…However, other studies have shown a close link between biogenic silica in surface sediment and biosiliceous productivity patterns in overlying waters (e.g., Mortlock and Froelich, 1989;Koning et al, 2002). Further studies have linked downcore traces of biogenic silica to local paleoproductivity records with Milankovitch-like cycles (Mortlock and Froelich, 1989;Pisias, 1976;Pisias and Leinen, 1984).…”

A 420,000‐year record of cyclicity in oceanic and atmospheric processes from the eastern equatorial Pacific

“…Thompson and Saito [ 1974] carded out preservation studies and clearly documented the association of well-preserved microfossils with the high carbonate glacial intervals. Since then, paleocean,graphers have interpreted the Pacific carbonate cycles as dominated by a preservation-dissolution signal, reflecting the changing carbonate chemistry of deep water [Pisias, 1976]. Adelseck and Anderson [ 1978] have argued that cores recovered well above the compensation depth contain a productivity record in the CaCO3 contents.…”