Late Cretaceous stratigraphy, sedimentology, and macropaleontology of Seymour Island, Antarctic Peninsula. (volumes I and II) [microform]
- Bib ID:
- 3287549
- Format:
- Book and Microform
- Author:
- Macellari, Carlos Enrique
- Description:
- 657 p.
- Summary:
-
Seymour Island, located east of the Antarctic Peninsula, had a continuously exposed marine sequence of friable siltstones and occasional indurated sandstones. The portion of the sequence studied includes the late Companian-Paleocene Lopez de Bertodano, Sobral, and Cross Valley formations, all belonging to the Marambio Group. These sediments were studied and sampled in detail during two field seasons. This new collection has provided extensive data on the stratigraphic distribution of an abundant and well preserved macrofauna. Sixty three taxa of annelids, bivalves, ammonites, and gastropods are described in detail, including 11 new species and 12 new occurrences for the area. Two groups are stratigraphically useful: the annelids and the ammonites. The Lopez de Bertodano Formation has been divided into four Rotularia (Annelida) zones, locally useful for correlation within the James Ross Island Basin.
The ammontes, however, which cluster into three zones, allow correlation of the sequence with other Maastrichtian localities throughout the world. Glauconite ages obtained in the Marambio Group provide an independent confirmation of the Maastrichtian to Paleocene age of the sequence. The Marambio Group on Seymour Island is the records of a transgressive-regressive cycle. The lower portion of the Lopez de Bertodano Formation is interpreted as a very shallow marine deposit influenced by a major river output. Successively deeper water sediments are interpreted to occur up section, ranging from middle shelf to outer shelf/slope break and upper slope facies. This trend towards deeper water conditions is mirrored in a sharp increase in the macrofaunal diversity. The upper part of the Lopez de Bertodano, Sobral, and the Cross Valley formations were deposited during the regression and represent middle shelf, prodelta, and delta top facies, respectively.
Marambio Group sandstones, which range from subarkoses to lithic arenites, were deposited in a back-arc tectonic setting. Both an igneous-metamorphic source and a volcanic source, located in the Antarctic Peninsula, supplied sediments to the basin. The sedimentary record indicates that active volcanism began during the late Maastrichtian and probably ceased during the late Paleocene.
- Notes:
-
- (UnM)AAI8504048
- Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0094.
- Thesis (Ph.D.)--The Ohio State University, 1984.
- Reproduction:
- Microfiche. Ann Arbor, Mich.: University Microfilms International.
- Subject:
- Geology
- Other authors/contributors:
- Ohio State University
- Copyright:
-
In Copyright
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Copyright status was determined using the following information:
- Material type:
- Literary Dramatic Musical
- Published status:
- Unpublished
- Creation date:
- 1984
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