Paleocene MORB and OIB from the Resolution Ridge, Tasman Sea.

Mortimer, N., Gans, P. B., Hauff, Folkmar and Barker, D. H. N. (2012) Paleocene MORB and OIB from the Resolution Ridge, Tasman Sea. Australian Journal of Earth Sciences, 59 (6). pp. 953-964. DOI 10.1080/08120099.2012.676569.

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Abstract

Altered lavas have been dredged from three locations on the Resolution Ridge, west of New Zealand's South Island. On the basis of whole-rock geochemistry, Sr, Nd and Pb isotope data and Ar–Ar ages, they can be divided into two suites: 62–60 Ma enriched mid-ocean ridge basalt (E-MORB), and 57 Ma trachybasalt and trachyandesite of ocean island basalt (OIB) affinity. The E-MORBs from the Resolution Ridge are only the second place from which Tasman Sea abyssal oceanic crust has ever been sampled, they have Indian MORB-like isotope compositions, and their ages support a recent interpretation of a 100 km sinistral offset of the southern part of the Tasman Sea spreading ridge. The slightly younger OIB suite erupted shortly after oceanic crust formation and has FOZO to HIMU source characteristics similar to the well-known SW Pacific Diffuse Alkaline Magmatic Province (DAMP). The close occurrence and isotopic mixing relationships of both Paleocene volcanic suites on the Resolution Ridge may be explained by a heterogeneous upper mantle in which the more fertile OIB component was extracted during a later melting event away from the spreading ridge. The dredged lavas predate formation of Southeast Tasman oceanic crust that borders the Resolution Ridge to the south.

Document Type: Article
Keywords: Resolution Ridge, Tasman Sea, MORB, OIB, petrology, geochemistry, isotope chemistry, argon–argon dating, Paleocene, tectonics
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1080/08120099.2012.676569
ISSN: 0812-0099
Projects: Future Ocean
Date Deposited: 07 Aug 2012 11:45
Last Modified: 08 Jun 2018 09:20
URI: http://oceanrep.geomar.de/id/eprint/15000

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