岩浆成矿体系的热演化和剥露史的数字模拟

傅清平; McInnesBrent I.A.; DaviesPeter J.

Volume 29 Issue 5

Sep. 2004

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FU Qing-ping, McInnes Brent I.A., Davies Peter J., 2004. Numerical Modelling of Thermal and Exhumation Histories of Magmatic Ore Deposits. Earth Science, 29(5): 555-562.

Citation:

FU Qing-ping, McInnes Brent I.A., Davies Peter J., 2004. Numerical Modelling of Thermal and Exhumation Histories of Magmatic Ore Deposits. Earth Science, 29(5): 555-562.

FU Qing-ping, McInnes Brent I.A., Davies Peter J., 2004. Numerical Modelling of Thermal and Exhumation Histories of Magmatic Ore Deposits. Earth Science, 29(5): 555-562.

Citation:

FU Qing-ping, McInnes Brent I.A., Davies Peter J., 2004. Numerical Modelling of Thermal and Exhumation Histories of Magmatic Ore Deposits. Earth Science, 29(5): 555-562.

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Numerical Modelling of Thermal and Exhumation Histories of Magmatic Ore Deposits

1.
School of Geosciences, University of Sydney, NSW 2006, Australia
2.
CSIRO Exploration and Mining, Perth, WA 6151, Australia

Received Date: 2004-06-15
Publish Date: 2004-09-25

Abstract

Abstract

The purpose of this paper is to quantify the thermal and exhumation histories of magmatic ore deposits by combining U-Th-He thermochronometrical data with computer modelling techniques.The numerical modelling of magmatic cooling has been first attempted and then integrated with the exhumation cooling to produce a digitized cooling curve which is further constrained by U-Th-He thermochronometer.The modelling results indicate that the magmatic cooling of igneous bodies is complicated.The cooling history of an igneous body can be divided into two distinct stages.In the first stage, the igneous body cools rapidly while the ambient country rock is heated simultaneously.In the second stage, the temperature of the igneous body is slightly higher than or close to that of the country rock, but the geothermal gradient in the vicinity is still higher than the initial thermal conditions, and thus both the igneous and country rocks cool slowly until both reach a final thermal equilibration under the normal thermal conditions.The cooling of the igneous body is affected by many factors, among which the size and the emplacement depth are the principal factors controlling the cooling rates and the durations of the two cooling stages.The complete thermal history requires an understanding of the exhumation history and this is achieved by the combined modelling of thermal and exhumation cooling resulting in a temperature-age curve constrained by the apatite U-Th-He, zircon U-Th-He, and zircon U-Pb age data.The validity of this curve was successfully tested against data obtained from porphyry copper deposits in Iran.The digitized temperature-age curve defines the time and depth of emplacement, crystallization age of economic minerals, cooling rate, cooled and exposure ages, and exhumation/erosion rates for the porphyry copper deposit.Therefore, the combination of highly precise age dating and computer modelling techniques can not only quantify the thermal and exhumation histories of ore systems, but also provide an insight into the genesis of the ore deposits.
- numerical modelling,
- magmatic cooling,
- exhumation history,
- magmatic ore deposits

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References(26)

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