HUANG Du-bin，GUAN Xin-bang

(School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing100083, China)

Abstract: The mineralogical features of chloritoid in Hongmiaoling Formation of Dongshan, Tanzhesi, West Beijing, China were studied by using polarization microscope, X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results show that, rose-like or fasciculate chloritoid in this area is monoclinic crystal with contact twin. Its chemical formula can be written as (Fe2+, Mg) (Al, Fe3+)2SiO5(OH)2 as Fe2+ is oxidized to Fe3+ and replaces Al3+.Paragonite is found in the sample,indicating the metallogenic temperature of 350–500 ℃. The orientation of chloritoid shows that chloritoid is a stress mineral, and its formation may be related to the deeply structural controlled hydrothermal activities.

Key words: chloritoid; mineralogical feature; stress mineral; Tanzhesi; Beijing

E-mail:　cumtbhdb@126.com

ACTA MINERALOGICA SINICA Vol. 32, No. 2, 2012, Page 200-204