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本文通过对辽西朝阳地区含鸟化石层附近侏罗—白垩系蓝旗组、土城子组、义县组地层共1252块古地磁样品的测试与分析,建立了以上沉积地层的磁极性序列,发现蓝旗组、土城子组地层的磁极性序列具有频繁的正、反极性,而义县组则为单一正极性,结合现有古生物和同位素年龄资料,对比国际中生代地磁极性年表,表明土城子组的磁极性序列相当于提塘期、基末里期、牛津期和卡洛期,其主体的地质时代应属晚侏罗世(J_3),土城子组底部的地质时代应属中侏罗世(J_2);并且根据义县组含鸟化石层以上层位的磁性地层研究结果,认为义县组合鸟化石的正极性带可与M_(16)正极性时相对应,义县组含鸟类化石层的时代应属早白垩世早期,辽西白垩系/侏罗系界线很可能位于义县组/土城子组之间。
Based on the testing and analysis of a total of 1252 paleomagnetic samples from the Jurassic-Cretaceous Lanqi, Tuchengzi and Yixian formations in the Chaoyang area, western Liaoning Province, the magnetic polarity sequence of the above sedimentary strata was established and found The polar sequences of the Lanqi and Tuchengzi formations have frequent positive and negative polarities, while the Yixian Formation is of a single positive polarity. Comparing the existing Mesozoic geomagnetic polarity chronology with the existing paleontology and isotopic ages, The magnetic polarity sequence of Tuchengzi Formation is equivalent to that of Late Tang Dynasty, Basement Period, Oxford Period and Carlow Period. The main geological period of Tuchengzi Formation should belong to Late Jurassic (J_3), and the geologic age at the bottom of Tuchengzi Formation should belong to Jurassic (J_2); and according to the results of magnetic strata above the Yixian Formation containing birds and fossils, it is concluded that the positive polarity band of the Yixian combined bird fossil may correspond to the positive phase of M_ (16) The era of avian fossil beds should belong to the early Early Cretaceous, and the Cretaceous / Jurassic boundary of western Liaoning is likely to be located between Yixian / Tuchengzi groups.