New Zealand Journal of Geology
and Geophysics abstracts
Diagenetic history of Triassic
sandstone from the Beacon Supergroup in central Victoria Land,
Antarctica
Matthias Bernet*
Reinhard Gaupp†
Institut
für Geowissenschaften
Johannes-Gutenberg Universität
Mainz, Germany
matthias.bernet@aya.yale.edu
*Present
address: State University of New York, New Paltz, USA.
†Present
address: Institut für Geowissenschaften, Friedrich
Schiller Universität, Jena, Germany.
Abstract The
diagenetic history of Triassic sandstone from the Beacon Supergroup,
Victoria Land, Antarctica, can be divided into three main phases of
shallow burial diagenesis, contact diagenesis (temperatures of
200–300°C), and post-contact diagenesis, on the basis of
petrographic and geochemical analyses. Shallow burial diagenesis is
characterised by minor compaction, K-feldspar alteration to illite, and
quartz cementation. Contact diagenesis is related to emplacement of
dolerite intrusions and basalt flows during Gondwana break-up at
180 Ma. This high-temperature diagenetic phase is dominated by
zeolite cementation, even in sandstone poor in zeolite precursor
materials. Elevated thermal conditions associated with the igneous
intrusions are suggested by increased illite crystallinity, but strong
evidence for contact metamorphism is missing. Post-contact diagenesis
is signified by zeolite and K-feldspar dissolution, and local quartz,
calcite cementation, and minor albite and K-feldspar precipitation.
This diagenetic phase is possibly related to renewed (hydro-) thermal
activity in Victoria Land in association with rifting of New Zealand
and Australia from Antarctica at c. 96 Ma.
Keywords contact
diagenesis; zeolite cementation; dolerite intrusion; Beacon Supergroup;
Antarctica
G04040; Received 18 October
2004; accepted 5 May 2005; Online publication date 22 August 2005
New Zealand Journal of Geology
& Geophysics, 2005, Vol. 48:
447–458
0028–8306/05/4803–0447© The Royal Society of
New Zealand 2005
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