Potassium variation across the New Britain volcanic arc |
| |
Authors: | R.W. Johnson |
| |
Affiliation: | Bureau of Mineral Resources, Canberra City, A.C.T. Australia |
| |
Abstract: | Late Cainozoic volcanoes of the New Britain island arc overlie an inclined Benioff zone that extends to a depth of at least 580 km. The rocks are tholeiitic basalt, andesite, dacite, and rhyolite. Unlike many other examples of island arcs described in the literature, K2O contents in rocks with the same SiO2 content do not increase progressively as depth,h, to the New Britain Benioff zone increases. The most complex relationships between K2O, SiO2, andh are shown by volcanoes overlying the deeper part of the Benioff zone. In these, the K2O contents of rocks containing more than about 60% SiO2,decrease as depth to the Benioff zone increases. The New Britain volcanic arc provides a striking exception to the generalisation thatK-h relationships are essentially similar in all island arcs. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|