Tectonic Framework and Evolution of the Dabie Mountains in Anhui, Eastern China

AbstractWe have found >10 in situ microdiamonds in thin sections of eclogites from the Dabie and Su-Lu regions of central eastern China since the first occurrence of microdiamond in eclogites from the Dabie Mountains (DMT) reported in 1992. The microdiamonds are found not only in the central part but also in the northern part of the DMT. Several free crystals have been recovered from the crushed eclogites from the central DMT. Most in situ microdiamonds are inclusions in garnets but a few larger ones are intergranular. Most of the diamondiferous eclogites in the central part of the DMT are associated with coesite. Most importantly, the observation of microdiamonds in northern Dabie lead us to question the supposition that this is a low-P metamorphic terrane. All the diamondiferous eclogites from both the north and central DMT are of continental affinity as demonstrated by their negative εNd values. Therefore, both the north and central eclogite belts in the DMT are considered to be from the deep subducted terrane. Five in situ microdiamonds and two free crystals are first reported in this paper. The dimensions of the in situ microdiamonds are 30–180 µm and the free crystals are up to 400–700 mm across. All the microdiamonds are confirmed as such by Raman spectroscopy. The results of an infrared spectroscopic investigation on two larger free crystals and two in situ microdiamonds show that all the microdiamonds from both the Dabie and Su-Lu regions are mixed types IaA and IaB diamonds and there is no indication of any synthetic microdiamonds in our samples because such synthetic microdiamonds are always rich in type Ib.

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Eclogites from the Northern Dabie Mountains, eastern China: Geochemical characteristics, Sr−Nd isotopic compositions and tectonic implications

Science in China Series D Earth Sciences ◽

10.1007/bf02911943 ◽

2000 ◽

Vol 43 (S1) ◽

pp. 178-188 ◽

Cited By ~ 4

Author(s):

Yican Liu ◽

Shutong Xu ◽

Shuguang Li ◽

Laili Jiang ◽

Weiping Wu ◽

...

Keyword(s):

Eastern China ◽

Geochemical Characteristics ◽

Dabie Mountains ◽

Isotopic Compositions ◽

Tectonic Implications

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Different origins of adakites from the Dabie Mountains and the Lower Yangtze River Belt, eastern China: geochemical constraints

International Geology Review ◽

10.1080/00206814.2010.482349 ◽

2010 ◽

Vol 53 (5-6) ◽

pp. 727-740 ◽

Cited By ~ 89

Author(s):

Ming-Xing Ling ◽

Fang-Yue Wang ◽

Xing Ding ◽

Ji-Bin Zhou ◽

Weidong Sun

Keyword(s):

Yangtze River ◽

Eastern China ◽

Dabie Mountains ◽

Lower Yangtze ◽

Different Origins ◽

Geochemical Constraints

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Hydrolytic weakening of jadeite in UHP jadeite-quartzites from the Dabie Mountains, eastern China

Mineralogical Magazine ◽

10.1180/0026461067050354 ◽

2006 ◽

Vol 70 (5) ◽

pp. 509-515 ◽

Cited By ~ 4

Author(s):

Wen Su ◽

Kai Ye ◽

Jingbo Liu

Keyword(s):

Plastic Deformation ◽

Eastern China ◽

Dislocation Creep ◽

Dabie Mountains ◽

Dislocation Loops ◽

Transmission Electron ◽

Dislocation Arrays ◽

Show Evidence ◽

Electron Energy Loss ◽

Dislocation Walls

AbstractDeformed jadeite grains in the UHP jadeite-quartzites from the Dabie Mountains, eastern China show evidence (by transmission electron microscopy, TEM) of plastic deformation: free dislocations, dislocation loops, dislocation networks, dislocation arrays and regularly spaced subgrain boundaries by dislocation walls. Electron energy-loss spectroscopy and TEM studies reveal the existence of water-rich bubbles within dislocations and imply a relationship with water-defect dislocation by water weakening in the jadeites. These observations suggest that the water-rich bubbles are a major weakening effect facilitating plastic deformation of jadeite by dislocation creep.

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