冀北康保晚古生代花岗质岩浆作用年龄数据及构造意义

冀北康保位于华北克拉通北缘中段，北靠古亚洲洋构造域（中亚造山带）。区内出露有小西沟、前孟家地、石柱梁、三老虎、新村和西五福堂等6个晚古生代花岗岩体，它们的锆石U-Pb年龄分别为260.6±1.6 Ma、264.1±1.7 Ma、269.5±2.7 Ma、276.3±1.9 Ma、280.4±2.0 Ma和284.7± 1.7 Ma等，表明这些花岗岩体形成于早-中二叠世。晚古生代（早-中二叠世）花岗岩体在冀北康保有规律地出露，应该与古亚洲洋的构造演化有关，可能反映了古亚洲洋的俯冲消减作用具有多期次的特点。

Late Paleozoic granites within Kangbao area,North Hebei Province: Zircon U-Pb dating and tectonic implications

The Kangbao area in Hebei Province is located in the central part of the northern margin of the North China Craton, which is bounded by the Paleo-Asian Ocean tectonic region（also known as the central Asia orogenic belt）to the north. The six kinds of Late Paleozoic granitic intrusive bodies, such as Xiaoxigou, Qianmengjiadi, Shizhuliang, Sanlaohu, Xincun and Xiwufutang, are found within Kangbao County. Zircon LA-ICP-MS isotopic dating of six different samples from the above-mentioned granitic bodies defines six weighted mean ages of about 260.6±1.6 Ma, 264.1±1.7 Ma, 269.5±2.7 Ma, 276.3±1.9 Ma, 280.4±2.0 Ma and 284.7± 1.7 Ma respectively, which is interpreted as the emplacement age of the granitic intrusive bodies and reflects the occurrence of acidic magmatism during the Early-Middle Permian. The granitic bodies from Kangbao area, Hebei Province is related to subduction of Paleo-Asian oceanic crust beneath the North China Craton during Late Paleozoic and shows the tectonic evolution of Paleo-Asian Ocean has multiperiodic characters.