Geosphere; February 2008; v. 4; no. 1;
p. 292-314; DOI: 10.1130/GES00111.1
© Geological Society of America
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Figure 3. Generalized geological map of the Gaoligong Shan and the Chong Shan shear zones (GSSZ and CSSZ) and the rock units they separate. Main tectonic elements are labeled: BaS—Baoshan, L—Lhasa, T—Thengchong. The location of the geological cross sections that are discussed in the text are lettered a through g and are circled. Major towns that are easy to locate on any road map of Yunnan Province, rather than the small villages that the cross sections are closest to, are also labeled. Block diagrams schematically represent structural setting of the samples dated. All of the rocks forming the Chong Shan shear zone (d in the schematic block diagrams), except for the discontinuous bands of marble, regardless of their degree of metamorphism, have been intruded by cm- to dm-scale pegmatitic, leucogranitic, and aplitic sills of granitic composition. While some of the granitic intrusions within the migmatitic section of the Chong Shan shear zone contain a folded foliation, the intrusions into the granitoid and pelitic gneisses show evidence for only one deformational event and can be grouped by their degree of deformation as follows: (A) unfoliated dikes that crosscut the foliation, (B) unfoliated, foliation-parallel sill, and (C) foliated, foliation-parallel sill. None of these sills and dikes contains a lineation, even though the host rocks they intrude display a prominent subhorizontal, mylonitic lineation associated with the strike-slip shearing along the Chong Shan shear zone. Structural setting for each sample is shown to the right of the sample number. mnz—monazite, M—muscovite, B—biotite.
Copyright © 2008 by Geological Society of America
