R. Oberhänsli, G. Martinotti, R. Schmid, X. Liu; Preservation of primary volcanic textures in the ultrahigh-pressure terrain of Dabie Shan. Geology ; 30 (8): 699–702. doi: https://doi.org/10.1130/0091-7613(2002)030<0699:POPVTI>2.0.CO;2
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Delicate primary volcanic features such as ash layers, volcaniclastic breccias, and pillow lavas with amygdaloidal rims have been identified in a terrigenous volcanosedimentary sequence forming part of the ultrahigh-pressure unit of the Dabie Shan, China. The presence of coesite relics in crosscutting dikes confirms an ultrahigh-pressure evolution for the entire sequence. Evaluation of the probable reaction history for zeolite compositions as supposed for the amygdaloidal rims reveals a scarcity of reactions at very high pressures. Such special conditions of low reactivity and fluid-conserving reactions, combined with a lack of directed stress, have allowed the remarkable preservation of these primary volcanic features despite deep subduction.