Compilation and time-series analysis of a marine carbonate delta O-18, delta C-13, Sr-87/Sr-86 and delta S-34 database through Earth history

摘要

The Sr, S, O and C isotope database of marine carbonates contains over 55,000 published isotope values of low-Mg calcite from diagenetically little altered Phanerozoic fossil shells as well as samples of whole rocks and calcite cements of Ordovician to Archean age. Carbon and oxygen isotope data for the shell material are divided into habitat subsets (high-, mid-, low-latitude and deep sea), and whole rock data are separated by mineralogy into calcite/dolomite subsets. Trend, correlation, wavelet, and spectral analyses on Gaussian-filtered isotope records were applied to detect and quantify similarities and patterns in temporal records with the following results: Oxygen isotope trends from the "high-latitude" and "deep-sea" habitats are almost indistinguishable through the last 115 Ma, consistent with the existence of the "oceanic conveyor belt" throughout this interval; All oxygen isotope habitat records show a strong, coherent 30-45 Ma (similar to 38 Ma) cyclicity throughout the Cretaceous and the Cenozoic Up to 70% of the multi-million year variability in the 6180 record of the last 115 Ma can be simulated by the following equation: delta O-18(parts per thousand) = 0.64 sin (27 pi t/120 Ma + 0.9) +Xsin (2 pi t/38.3 Ma + 1.1) with X ranging from 0.4-0.6 parts per thousand for the "low- ", "high-latitude" and "deep-sea" habitats, to 0.8 parts per thousand for the "mid-latitude" realm. A similar to 120 +/- 20 Ma cycle occurs in the Paleozoic and Neoproterozoic delta O-18 record, consistent with paleoclimate variability as interpreted from sedimentological and faunal records. The offset of delta C-13 values between "deep water" and "high-latitude" vs. surficial habitats at lower latitudes is consistent with the operation of a biological pump in the oceans since at least the Cretaceous. Sr and S isotope records exhibit a similar to 60-70 Ma cyclicity throughout the Phanerozoic. (c) 2008 Elsevier B.V All rights reserved.