Magma source variations for mid–late Tertiary magmatic rocks associated with a shallowing subduction zone and a thickening crust in the central Andes (28 to 33°S) 论文

详细信息

发表期刊/会议

Geological Society of America Special Papers

发表日期

1991-01-01

发表年份

1991

摘要

The distribution, petrology, and geochemistry of mid-late Tertiary magmatic rocks in the Main Andean Cordillera over the modern zone of shallow subduction ("flat-slab" −28 to 33°S) correlate with the shallowing of the subducted plate and the thickening of the crust in central Chile and Argentina. The evolving characteristics of these "flat-slab" magmatic rocks suggest that crustal thickening occurred earlier in the central (near 30.5°) and northern (near 28°S) regions than in the southern region (near 33°S). Crustal thicknesses approximated by comparing the chemical characteristics (particularly the La/Yb ratios) of the "flat-slab" magmatic rocks with those of similar rocks in the...