Heat flow data from the southeast of South Australia: distribution and implications for the relationship between current heat flow and the Newer Volcanics Province

Simple item page
dc.contributor.authorMatthews, C.
dc.contributor.authorBeardsmore, G.
dc.contributor.authorDriscoll, J.
dc.contributor.authorPollington, N.
dc.date.issued2013
dc.description.abstractThis paper presents the results of 34 new heat flow estimates taken in 2004 from 16 water bores and 18 petroleum exploration wells in the western Otway Basin. The average estimated heat flow measured across the study area is 65.6 ± 9.4 mW/m2, with a range of 42–90 mW/m2. There are three recognisable sectors within the study area where heat flow is slightly elevated relative to the background levels. These sectors can be broadly classified as Mount Schank (73.5 ± 0.5 mW/m2), Mount Burr (71.2 ± 7.6 mW/m2) and Beachport (78.3 ± 10.4 mW/m2). Thermal conductivity values for each unit involved in heat flow estimation were determined from laboratory measurements on representative core using a divided bar apparatus. Borehole thermal conductivity profiles were then developed in this study by assigning a constant value of conductivity to each geological formation. The process of collecting temperature data involved measuring temperature profiles for 16 water bores using a cable, winch and thermistor, and compiling well completion temperature data from 18 petroleum wells. The precision of temperature data was higher in the water bores (continuous logs) than in the petroleum wells (largely bottom-of-hole temperature estimates). Inversion heat flow modelling suggests heterogeneous heat flow at 6000 m depth, with two zones where vertical heat flow might exceed 90 mW/m2, and several zones where vertical heat flow might be as low as 40 mW/m2. Therefore, while slightly higher surface heat flow does coincide with some of the volcanic centres, heterogeneous basement heat production is a more likely explanation, as there are no heat flow anomalies greater than 5–10 mW/m2 associated with the Pleistocene–Recent Newer Volcanics Province. The distribution of heat flow in south-east South Australia is most simply explained by non-volcanic phenomena.
dc.description.statementofresponsibilityChris Matthews, Graeme Beardsmore, Jim Driscoll and Nicky Pollington
dc.identifier.citationExploration Geophysics, 2013; 44(2):133-144
dc.identifier.doi10.1071/EG12052
dc.identifier.issn0812-3985
dc.identifier.issn1834-7533
dc.identifier.urihttp://hdl.handle.net/2440/79662
dc.language.isoen
dc.publisherAustralian Society of Exploration Geophysicists
dc.rightsJournal compilation © ASEG 2013
dc.source.urihttps://doi.org/10.1071/eg12052
dc.subjectAustralia
dc.subjectDelamerian Fold Belt
dc.subjectgeothermal modelling
dc.subjectheat flow
dc.subjectNewer Volcanics Province
dc.subjectOtway Basin
dc.subjectthermal conductivity
dc.subjectthermal gradient
dc.titleHeat flow data from the southeast of South Australia: distribution and implications for the relationship between current heat flow and the Newer Volcanics Province
dc.typeJournal article
pubs.publication-statusPublished

Files

Collections

Institute for Mineral and Energy Resources publications