Uppermost Oligocene and Miocene diatom biostratigraphy of Ocean Drilling Program Sites 682 and 688 from the Peru Margin

Stratigraphy
By: , and 

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Abstract

The diatom biochronology of ODP (Ocean Drilling Program) Holes 682A and 688E provides a detailed framework for refiningMiocene diatom zonation in the East Pisco Basin of southern Peru, establishing both a nearly complete offshore reference section and a correlation tool for the fragmentary onshore vertebrate-bearing deposits. This new biostratigraphic record documents a complete succession of low latitude and/or northeastern Pacific Miocene diatom zones, with two notable exceptions: a dissolution and/or hiatus interval (*16.5–14 Ma) during the Middle Miocene Climatic Optimum and a likely earliest Miocene hiatus (*23.4–21.8 Ma). Although eastern equatorial Pacific diatom zones characterize the Upper Oligocene and Lower Miocene strata, an increased abundance of cool-water diatoms that lived during the Middle and Late Miocene allows better application of northeast Pacific diatom zones, except during the Messinian (7–6 Ma) when warm-water diatoms predominate. The effects of eustatic sea level and tectonics on depositional sequences in the EPB and in offshore cores off central Peru are discussed.

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Publication type Article
Publication Subtype Journal Article
Title Uppermost Oligocene and Miocene diatom biostratigraphy of Ocean Drilling Program Sites 682 and 688 from the Peru Margin
Series title Stratigraphy
DOI 10.29041/strat.22.3.01
Volume 22
Issue 3
Year Published 2025
Language English
Publisher Micropaleontology Press
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 26 p.
First page 155
Last page 180
Country Peru
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