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Low-temperature emplacement of phreatomagmatic pyroclastic flow deposits at the monogenetic Mt Gambier volcanic complex, South Australia, and their relevance for understanding some deposits in diatremes
Citation
Van Otterloo, J and Cas, RAF, Low-temperature emplacement of phreatomagmatic pyroclastic flow deposits at the monogenetic Mt Gambier volcanic complex, South Australia, and their relevance for understanding some deposits in diatremes, Journal of the Geological Society, 173, (4) pp. 701-710. ISSN 0016-7649 (2016) [Refereed Article]
Copyright Statement
© 2016 The Author(s).
Abstract
The occurrence of pyroclastic flow deposits is not restricted to polygenetic and/or felsic volcanic systems, but can also
occur at mafic monogenetic volcanic centres. At the c. 5 ka Mt Gambier Volcanic Complex, Australia, two small-volume pyroclastic flow deposits resulted from phreatomagmatic eruptive
phases of the Blue Lake East and the Valley Lake maar craters. The facies descriptions of the two massive, poorly sorted lapilli
tuff and tuff breccia deposits are given. Low-grade carbonized wood fragments in the deposits mark low emplacement temperatures
(180–270°C) for these deposits with only c. 12–23% of the total thermal energy of the original magma preserved at the time of deposition. The Blue Lake East vent erupted
by forming a short-lived vertical eruption column, which could not be sustained and collapsed. The Valley Lake pyroclastic
flow deposit has a highly asymmetric dispersal to the west, indicating that this deposit was formed during an eruptive phase
with a large westward-directed lateral component. Such massive, poorly sorted deposits outside the maar crater indicate that
some similar deposits in diatremes may have originated from surface eruptions and not just from subsurface debris jets.
Item Details
Item Type: | Refereed Article |
---|---|
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Volcanology |
Objective Division: | Energy |
Objective Group: | Mining and extraction of energy resources |
Objective Field: | Mining and extraction of energy resources not elsewhere classified |
UTAS Author: | Cas, RAF (Professor Ray Cas) |
ID Code: | 115235 |
Year Published: | 2016 |
Web of Science® Times Cited: | 9 |
Deposited By: | Earth Sciences |
Deposited On: | 2017-03-10 |
Last Modified: | 2017-11-02 |
Downloads: | 0 |
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