The present paper reports the research development in the timing and tectonic setting of the Xixiang Group, northwestern margin of the Yangtze block. U-Pb concordant ages of (946+-18) Ma and (904+-18) Ma of zircons we...The present paper reports the research development in the timing and tectonic setting of the Xixiang Group, northwestern margin of the Yangtze block. U-Pb concordant ages of (946+-18) Ma and (904+-18) Ma of zircons were obtained from the upper and lower units of the Xixiang volcanic succession, respectively. Elemental and Nd isotope characteristics show that the volcanic suite has the affinities of arc island magmatism as well as an evolution trend of tectonic setting from front-arc to back-arc. The volcanic rocks suffered from some extensive post-stage tectonothermal events, resulting in the resetting of their Rb-Sr isotopic system.展开更多
The Xixiang Group in the southern Qinling has been believed to be a Precambrian metamorphic complex. Radiolarian fossils were found in the muddy chert interlayers of volcanic rocks in the Sunjiahe Formation of the gro...The Xixiang Group in the southern Qinling has been believed to be a Precambrian metamorphic complex. Radiolarian fossils were found in the muddy chert interlayers of volcanic rocks in the Sunjiahe Formation of the group. The ages of the fossils are Late Devonian and Early Carboniferous in the lower member and Early Carboniferous in the middle and upper members of the formation. The complex in the Xixiang area can be determined as a Paleozoic-Triassic melange which connects with the Mianxian-Lueyang ophiolitic melange.展开更多
基金This work was supported by the NationalNatural Science Foundation of China (Grant Nos. 49873010, 49794043 and 49573138) the Ministry of National Land and Resources of China (Grant No. 20001010203).
文摘The present paper reports the research development in the timing and tectonic setting of the Xixiang Group, northwestern margin of the Yangtze block. U-Pb concordant ages of (946+-18) Ma and (904+-18) Ma of zircons were obtained from the upper and lower units of the Xixiang volcanic succession, respectively. Elemental and Nd isotope characteristics show that the volcanic suite has the affinities of arc island magmatism as well as an evolution trend of tectonic setting from front-arc to back-arc. The volcanic rocks suffered from some extensive post-stage tectonothermal events, resulting in the resetting of their Rb-Sr isotopic system.
基金Project supported by the fundations of the Chinese Academy of Sciences and Ministry of Geology and Mineral Resources (MGMR) for 100 outstanding young scientists.
文摘The Xixiang Group in the southern Qinling has been believed to be a Precambrian metamorphic complex. Radiolarian fossils were found in the muddy chert interlayers of volcanic rocks in the Sunjiahe Formation of the group. The ages of the fossils are Late Devonian and Early Carboniferous in the lower member and Early Carboniferous in the middle and upper members of the formation. The complex in the Xixiang area can be determined as a Paleozoic-Triassic melange which connects with the Mianxian-Lueyang ophiolitic melange.
