| Abstract: | Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80??? can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls. (C) 2000 Elsevier Science B.V. All rights reserved.Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80 per mil can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls. |
| Genre: | Conference Paper |
| ProdID: | 70022250 |
| Citation Author: | Jones, G.; Whitaker, F.; Smart, P.; Sanford, W. |
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| Citation End Page: | 75 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Geochemical Exploration |
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| Citation Number Of Pages: | 5 |
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| Citation Publisher: | Elsevier Science Publishers B.V. |
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| Citation Search Results Text: | Numerical modelling of geothermal and reflux circulation in Enewetak Atoll: Implications for dolomitization; 2000; Conference Paper; Journal of Geochemical Exploration; Jones, G.; Whitaker, F.; Smart, P.; Sanford, W. |
| Citation Start Page: | 71 |
| Citation Volume: | 69-70 |
| Citation Year: | 2000 |
| Type: | citation/reference |
| Text: | Numerical modelling of geothermal and reflux circulation in Enewetak Atoll: Implications for dolomitization; 2000; Conference Paper; Journal of Geochemical Exploration; Jones, G.; Whitaker, F.; Smart, P.; Sanford, W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/S0375-6742(00)00010-8 |
| Date Other: | Sat, 1 Jan 2000 00:00 -0600 |
| Publisher: | Elsevier Science Publishers B.V. |
