On the west limb , there are andesite clasts at the lower section and limestone clasts at the upper section , which indicates normal stratigraphic sequence in its provenance . on the east limb , there are dolomite clasts at the lower section and limestone clasts at the upper section , which indicates reversed stratigraphic sequence in its provenance 西翼礫巖在剖面上具明顯的倒序巖屑地層特征,反映了物源區(qū)正常的層序地層,而東翼礫巖在剖面上仍然是正序的巖屑地層,反映了物源區(qū)非正常的層序地層。