| The worked area is situated in the northeast part of Heilongjing Province,covering an area of about 600km2 in 4730 - 4830N and 130-131 E;geotectonically, belonging to the Jiamusi massif (Fig. 1). The area is northward connected together with the Burya massif of Russia, which is generally known as the Burya - Jiamusi medial massif.The Jiamusi massif is bounded by surrounding faults of Mudanjiang-Tangwang-he-Jielehe fault separating from the Zhangguangcailing orogenic belt on west,Dunhua-Mishan fault separating from the Yanbian fold system on southeast, and the Tongjiang-Dangbi fault separating from the Nadanhada terrane on east. The massif is composed mostly of Precambrian metamorphic rocks, granitic rocks and Mesozoic-Cenozoic coverings, arornd which the Palaeozoic strata are scattered. The Postpalaeo-zoic strata on the massif can be comparable with those on the surrounding units.The Precambrian metamorphic rock series used to be regarded as "stratigraphic unit"and divided into two groups,Heilongjiang and Mashan,but the sequence and contact relationship between the two groups have been argued for a long time. The major problems are as follows, a. On the bases of the concept of burial metamorophism, high-grade metamorphosed Mashan group ( high-amphibolite-granulit facies) should be beneath low-grade metamorphosed Heilongjiang group(greens-chist facies). b Vnusual field occurrence, the Mashan group overlying the Heilongjiang group was interpreted as"inverse metamorphic zoning", c. Owing to uncertainty relation of both groups, the metamorphic rocks which are difficult to be compared each other should be reconsidered to be"independent stratigraphic units".HEILONGJIANG COMPLEX We use the term "Heilongjiang complex"to substitute for the Heilongjiang group in order to distinguish tectonic rock association fromprevious" stratigraphic unit".For usage reason, division of metamorphic rock groups and formations is based on the assume that rock schistosity inherits original rock bedding. The geological evidence shows that almost all schistosities in the Heilong jiang Complex are new-formed mylo-nitic foliations by ductile deformation, which are not comsistent with original beddings. In fact, the foliations as boundary surface between different lithologies are "false:-bedding"formed by tectonic substitution and differentiation, and interbedded of intercalaed lithologic layers are without stable extension. The "stratigraphic formations" previously determined posses neither specific rock associations nor clear boundary marks. The pervasive foliate tectonics are reflected by prefer oriented flaky silicate minerals and elongated feldspars, quartzes and amphiboles, which doubtless resulted from recombination of materials and tectonic parallelism as ductile deformation. This rprocess includes physical(mcchanical) transformation,chemical rework and participation of fluid.The field relation indicates that the foliations in deformed rocks are consistent with pervasive regional foliation that is so strongly developed that former tectonic elements, including beddings, were destroyed. In this case, it is difficult to renew original beddings. Only in local exposure where relict primary bedding coexisting with regional foliatoin can be observed, are some small slip folds the manifestation of primary beddings (s0) that slip along regional pervasive foliation (s1). With the development of the folds,primary bedding(s0)became discontinuous and were finally replaced by the foli-ation(sl).As indicated above, the primary stratigraphic fabrics in the Heilong jiang Complex, for the most part,had been replaced by edformation is impracticable.The Heilongjiang Complex is composed chiefly of various mylonites and mylonitic schists that suffered varying degrees of ductile deformation. These foliated rocks are spatially distributed in belt, in which L-S fabrics indicate they resuled from nappe shear movement.
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