Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning,China:New 40Ar/39Ar dating of the Yixian and Tuchengzi Formations

We report new 40Ar/39Ar dating results obtained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby basaltic sill. The second is the Yixian Bed 9 tuff from Hengdaozi considered by Lo et al. to be unaffected by metamorphism and whose age, based on total fusion 40Ar/39Ar dating of biotite, argues for a Jurassic age for the Yixian Formation.The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion 40Ar/39Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ±0.04 (SE) Ma. Single sanidine crystal total fusion 40Ar/39Aranalyses of the Hengdaozi tuff gave a mean age of 125.0 +0.19 (1SD) ± 0.04 (SE) Ma, which is indistinguishable from the Sihetun tuff. The Tuchengzi Formation tuff gave a mean age of 139.4 ± 0.19 (1SD) ± 0.05 (SE) Ma. Detailed laser incremental-heating analyses of biotite from Sihetun, Hengdaozi, and Tuchengzi tuffs show disturbed Ar release patterns and evidence of trapped argon components. We conclude from these analyses that the total fusion dates on biotite by Lo et al. are erroneously old and isotopic dating of both biotite and sanidine from tuffs of the Yixian Formation point to a middle Early Cretaceous age. The upper part of the Tuchengzi Formation can be referred to the Early Cretaceous.``     

福建平潭岛火山岩及其板块碰撞构造

提出在福建东南沿海地区晚白垩世除了产出有拉张地球动力环境下火山（石帽山群火山岩）和深成（魁岐碱性花岗岩类）产物外，在长乐－南澳断裂带以东的平潭岛还产出有挤压地球动力环境下火山产物．其化学成分和岩系演化趋势显著不同于闽东南南园组和石帽山群火山岩，为独立的钙碱性角闪石英安岩系．其成因可能与库拉板块沿台湾中央山脉东侧向台湾海峡陆块的俯冲有关．闽东南地区早白垩世挤压环境火山产物（南园组火山岩）和晚自垩世拉张环境火山－深层岩系则可能与燕山早期台湾海峡陆块向闽东南大陆边缘的碰撞俯冲，而在晚白垩世停止俯冲，同时在台湾中央山脉东侧发生的俯冲作用所造成的“弧后扩张”有关．     

第三纪济阳盆地大地构造性质及其演化

依据中-小型构造、深部构造、地温场、岩浆活动、沉积建造、地貌和水文特征判断,早第三纪济阳盆地大地构造性质属大陆裂谷,其演化经历了前裂谷期裂谷孕育、裂谷期初始扩张裂陷—强烈扩张裂陷—晚期扩张裂陷—衰亡和后裂谷期拗陷漫覆6个阶段,晚第三纪为拗陷盆地.     

广东东莞木化石的首次发现

在广东东莞晚白垩世地层中首次发现一种新型木化石，定名为东莞云杉型木（新种）Ｐｉｃｅｏｘｙｌｏｎｄｏｎｇｇｕａｎｅｎｓｉｓ（ｓｐ．ｎｏｖ）．     

美洲黑杨新无性系生长动态遗传分析及早期选择

对４个区试点的５个美洲黑杨无性系的年生长动态进行了遗传分析。在不同区试点各无性系的年生长模式大致相似。遗传方差分量、广义遗传力随不同发育年龄而波动。生长早期选择是有效的，选择年龄为第４年     

Early Cambrian phosphatized blastula- and gastrula-stage animal fossils from southern Shaanxi

Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.     

江西玉山Etagraptus approximatus笔石带疑源类化石的发现及其意义

首次报道发现于江西玉山Etagraptus approximatus笔石带的疑源类化石，计12属23种，其中包括3个未定种，含量最高的3属是Stelliferidium、Polygonium、Micrhystridium，占总含量的77．4％，此外，Multiplicisphaeridium、Caldariola、Baltispharidium、Pteinosphaeridium也较常见，一定程度上反映了阿伦尼格期早期疑源类组合面貌。     

建国初期粤北地区土地改革运动述评

解放初期粤北地区的土地改革运动．是在北江地委和北江专署直接领导下开展的一场伟大的社会变革。整个运动从试点开始，经过清匪反霸、减租退押，划分阶级、分配土地，普遍复查、颁发土地证三个阶段，分三批由点带面、点面结合有序进行。虽然在运动中出现过“左”的错误倾向，但大都得到了及时有效的纠正，确保了土地改革运动的伟大胜利。对这一重大历史事件的回顾和评议，有利于正确认识社会发展的道路和粤北农村变革的艰辛。     

单星探测弹道特征信息提取方法研究

单星探测预警是天基预警系统发展的必然经历过程和重要组成部分,单星探测预警属于不完备测量,需要先验信息的支持才能估计弹道以及进行相应的预警,因此如何构建预警信息库就尤为重要。首先分析了一种弹道导弹的本质特征,并在此基础上建立了提取弹道特征信息的算法,从而使单星预警成为可能,仿真算例验证了该方法的可行性。