玄武岩喷发前公里规模的地壳抬升是大火成岩省地幔柱成因的一个重要标志,此类地质证据的缺乏反过来被一些学者用来否定地幔柱学说.本文在厘定峨眉山大火成岩省中冲积扇沉积记录的基础上,根据茅口组顶部的剥蚀特征,估算峨眉山地幔柱上升造成的地壳抬升幅度大于1000 m,这与Campbell and Griffiths的地幔柱理论模型基本吻合,从而为峨眉山大火成岩省的地幔柱形成机制,乃至激烈争议中的地幔柱学说提供了有力的佐证.
THE MAGNITUDE OF CRUSTAL UPLIFT PRIOR TO THE ERUPTION OF THE EMEISHAN BASALT: INFERRED FROM SEDIMENTARY RECORDS
Kilometer-scale uplift prior to the eruption of basalt in large igneous province is the most remarkable characteristic for mantle plume model. However, few examples were documented in the international geological literatures and the mantle plume theory was disagreed upon by some geologists. This paper describes alluvial fan deposits in detail. Based on the geometry of the alluvial fan and the erosional features on the top of Maokou Formation, it is suggested that the magnitude of crustal uplift prior to the eruption of the Emeishan basalt is more than 1 ,000 m. This research result is well consistent with the crustal uplift caused by a starting mantle plume as predicted by Griffiths and Campbell modeling, and thus strongly supports a plume origin of the Emeishan flood basalts and the mantle plume theory as well.
Emeishan large igneous provincemantle plumecrustal upliftsedimentary record
NETL
NSTL
万方数据
维普
