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报道了对大别山高压 -超高压带河南罗山熊店和湖北英山蜜蜂尖两地榴辉岩单颗粒锆石SHRIMPU -Pb原位 (in situ)定年结果 .英山超高压榴辉岩年龄有 4组 :(773± 2 0 )Ma ,(73 0± 16)Ma ,(4 61± 7)Ma和 (2 62± 6)Ma ,其中以 (4 61± 7)Ma占绝对优势 .熊店高压榴辉岩有 3组年龄 :(4 4 9± 14 )Ma ,(3 0 7± 14 )Ma和 (2 16± 4)Ma .两地榴辉岩中均存在约 45 0Ma的早古生代奥陶纪年龄 ,它们均具有极低的Zr含量 (9× 10 - 6 ～ 19× 10 - 6 ) .结合熊店榴辉岩样品具有类似于MORB的微量元素特征和εNd值 (4 5 0Ma时为 + 6.5 6) ,说明该古生代年龄应代表古生代洋壳和岛弧物质俯冲经高压 -超高压变质作用的产物 .由于奥陶纪高压 -超高压事件的年龄同时出现在英山和熊店榴辉岩中 ,且熊店榴辉岩中清楚地记录了三叠纪高压-超高压事件 ,表明大别高压 -超高压带北界无论是在奥陶纪或三叠纪时均应在熊店榴辉岩以北的桐柏 -商城断裂
This paper reports the in-situ dating of SHRIMPU-Pb single-body zircon eclogite from the Xiongcheng store, Luoshan, Henan Province, and the beeswipod, Yingshan, Hubei Province in the Dabieshan high pressure- (773 ± 2 0) Ma, (73 0 ± 16) Ma, (4 61 ± 7) Ma and (62 62 ± 6) Ma, with 4 61 ± 7 Ma as the absolute advantage. There are three groups of high-pressure eclogite age: (4 4 9 ± 14) Ma, (3 0 7 ± 14) Ma and (2 16 ± 4) Ma.The Early Paleozoic ages of about 45 0Ma They all have very low Zr content (9 × 10 -6 ~ 19 × 10 -6). The Xiongdian eclogite samples have trace element characteristics similar to MORB and εNd values (at 450 Ma + 6.5 6), indicating that the Paleozoic age should represent the product of the subduction of the Paleozoic oceanic crust and island arc by high-pressure-ultrahigh pressure metamorphism.As the age of the Ordovician high-pressure event occurred at the same time, Rock, and the Triassic high pressure-ultrahigh pressure event clearly recorded in the Xiongdian eclogite, indicating that the northern boundary of the Dabie UHP-UHB should be covered by Xiongdianliu either during the Ordovician or Triassic Hui Yan north of Bo - Mall fracture