Cenozoic magnetostratigraphy of ODP holes 113-689B and 113-690B

DOI

A detailed paleomagnetic study was carried out on biosiliceous and calcareous sediments drilled on Maud Rise, Antarctica, during ODP Leg 113. High-quality APC sections were retrieved in the upper 220 m of Holes 689B and 690B. Average deposition rates range from 3 to 15 m/m.y. A close (25 cm) paleomagnetic sample spacing provided a medium-resolution magnetostratigraphic sequence for the Paleogene and Neogene. Paleomagnetic samples were demagnetized stepwise by alternating fields, and characteristic remanent magnetization directions were derived from detailed vector and difference vector component analysis.A magnetochronologic framework has been established for the first time for the Southern Ocean sedimentary sequences spanning Paleocene to Oligocene and middle Miocene to early Pliocene times. Biosiliceous and calcareous microfossil stratigraphies were used to constrain magnetostratigraphic age assignments. Although average sedimentation rates were rather low, nearly complete sections of the geomagnetic polarity time scale (e.g., Chrons C5 and C5A) could be correlated with the inferred polarity pattern. Miocene and Pliocene records are marked by a high number of hiatuses mainly identified by diatom biostratigraphy. Good paleomagnetic correlation between the two holes is afforded in particular in the middle to upper Miocene. Oligocene magnetostratigraphy reveals a high-quality paleomagnetic record with a mostly complete Oligocene section in Hole 689B at ~5 m/m.y. deposition rate. Hole 690B exhibits higher deposition rates (7-12 m/m.y.), although two hiatuses are present. Early and late Eocene sedimentary sequences could be analyzed in both holes, but in Hole 689B middle Eocene chrons were disrupted by hiatuses and only incomplete polarity intervals C21 and C24 were encountered. Highest resolution (14 m/m.y.) was achieved in Hole 690B in a complete early Eocene and late Paleocene sequence from Chrons C23 to C26, with a number of short polarity intervals detected within Chrons C24 and C25.

Supplement to: Spieß, Volkhard (1990): Cenozoic magnetostratigraphy of Leg 113 drill sites, Maud Rise, Weddell Sea, Antarctica. In: Barker, PF; Kennett, JP; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 113, 261-315

Identifier
DOI https://doi.org/10.1594/PANGAEA.726436
Related Identifier https://doi.org/10.2973/odp.proc.sr.113.182.1990
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.726436
Provenance
Creator Spieß, Volkhard
Publisher PANGAEA
Publication Year 1990
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 4 datasets
Discipline Earth System Research
Spatial Coverage (1.205W, -65.161S, 3.100E, -64.517N); South Atlantic Ocean
Temporal Coverage Begin 1987-01-16T08:00:00Z
Temporal Coverage End 1987-01-21T07:00:00Z