Temperature profile around a basaltic sill intruded into wet sediments

Journal of Volcanology and Geothermal Research
By: , and 

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Abstract

The transfer of heat into wet sediments from magmatic intrusions or lava flows is not well constrained from field data. Such field constraints on numerical models of heat transfer could significantly improve our understanding of water–lava interactions. We use experimentally calibrated pollen darkening to measure the temperature profile around a basaltic sill emplaced into wet lakebed sediments. It is well known that, upon heating, initially transparent palynomorphs darken progressively through golden, brown, and black shades before being destroyed; however, this approach to measuring temperature has not been applied to volcanological questions. We collected sediment samples from established Miocene fossil localities at Clarkia, Idaho. Fossils in the sediments include pollen from numerous tree and shrub species. We experimentally calibrated changes in the color of Clarkia sediment pollen and used this calibration to determine sediment temperatures around a Miocene basaltic sill emplaced in the sediments. Results indicated a flat temperature profile above and below the sill, with T > 325 °C within 1 cm of the basalt-sediment contact, near 300 °C at 1–2 cm from the contact, and ~ 250 °C at 1 m from the sill contact. This profile suggests that heat transport in the sediments was hydrothermally rather than conductively controlled. This information will be used to test numerical models of heat transfer in wet sediments on Earth and Mars.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Temperature profile around a basaltic sill intruded into wet sediments
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/j.jvolgeores.2015.06.012
Volume 302
Year Published 2015
Language English
Publisher Elsevier Science
Publisher location Amsterdam
Contributing office(s) Astrogeology Science Center
Description 6 p.
First page 81
Last page 86
Online Only (Y/N) N
Additional Online Files (Y/N) N