藏北南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层

对西藏自治区北部南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层进行了研究。根据岩石地层和生物地层资料,确认毕洛错地区的石膏岩层和油页岩为曲色组的一部分,地质时代为早侏罗世,并确认下侏罗统曲色组在区域上可能是寻找油气、油页岩资源的重要层位之一。     

A New Female Cone, Araucaria beipoiaoensis sp. nov. from the Middle Jurassic Tiaojishan Formation, Beipiao, Western Liaoning, China and Its Evolutionary Significance

A new species of Araucaria, Araucaria beipiaoensis sp. nov., collected from the Middle Jurassic Tiaojishan Formation, southern hill of Shebudai village, near Beipiao city, western Liaoning is based on a permineralized female cone, which is ovate to elliptical in shape, about 11 cm × 7 cm × 4.5 cm in size. The cone bears rhomboid bracts that are spirally attached, texture thicker, with wings on both sides, with a detached lamina-like apex at the tip. In inner structure the ovuliferous scales are thicker and fused with bracts at the end with a ligular sulcns. There is one wingless ovule/seed per seed-scale complex embedded in the ovuliferous scale tissue, with the micropyle directed toward the cone axis. The ovules/seeds are long ovate or elliptical in shape, 1 cm long and near the base about 3 mm in diameter; the ovule/seed integuments have begun differentiation into 3 layers： the sarcotesta, sclerotesta, and endotesta. The nucellus is free from the enclosing integuments except in the chalazal region where it is fused to the inner layer （endotesta） of integument. Some ovules show cellularized nucellar tissue. Mature seeds exhibit the papery-thin wavy nucellus characteristically near to the micropyle. The embryonic tissue appears to be four cotyledons. The morphology and structure of the cone shows a close relationship to the araucarian cones of fossil and living genera but differs from any known species. The new species is distributed in the Middle Jurassic of the northern hemisphere, especially Asia, and has important significance for the evolution of the Family Araucariaceae.     

Jurassic Tectonics of North China: A Synthetic View

This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in North China have been divided into three stages. The earliest Jurassic is marked by a period of magmatism quiescence （in 205-190 Ma） and regional uplift, which are considered to be the continuation of the “Indosinian movement” characterized by continent-continent collision between the North and South China blocks. The Early to Middle Jurassic （in 190-170 Ma） was predominated by weak lithospheric extension expressed by mantle-derived plutonism and volcanism along the Yanshan belt and alongside the Tan-Lu fault zone, normal faulting and graben formation along the Yinshan- Yanshan tectonic belt, depression and resuming of coal-bearing sedimentation in vast regions of the North China block （NCB）. The Middle to Late Jurassic stage started at 165y.5 Ma and ended up before 136 Ma; it was dominated by intensive intraplate deformation resulting from multi-directional compressions. Two major deformation events have been identified. One is marked by stratigraphic unconformity beneath the thick Upper Jurassic molasic series in the foreland zones of the western Ordos thrust-fold belt and along the Yinshan-Yanshan belt; it was predated 160 Ma. The other one is indicated by stratigraphic unconformity at the base of the Lower Cretaceous and predated 135 Ma. During this last stage, two latitudinal tectonic belts, the Yinshan-Yanshan belt in the north and the Qinling-Dabie belt in the south, and the western margin of the Ordos basin were all activated by thrusting; the NCB itself was deformed by the NE to NNE-trending structural system involving thrusting, associated folding and sinistral strike-slip faulting, which were spatially partitioned. Foliated S-type granitic plutons aged 160-150 Ma were massively emplaced in the Jiao-Liao massif east of the Tan-Lu fault zone and indicate important crustal thicken     

西藏冈底斯带侏罗纪岩浆作用的时空分布 及构造环境

在新近完成的1：25万区域地质调查资料和相关研究成果的基础上,初步研究了西藏冈底斯带侏罗纪岩浆作用的分布特点及其年代学,并利用已有的地球化学数据重点分析了早期关注程度较低的侏罗纪花岗岩类岩浆作用的性质。目前在冈底斯弧背断隆带未发现侏罗纪火山岩;在冈底斯东部地区,早侏罗世岩浆活动几乎同时发生于南冈底斯（叶巴组火山岩和鸟郁、尼木花岗岩类）、冈底斯弧背断隆带（宁中、金达、布久花岗岩类）和北冈底斯（聂荣花岗岩类）,中晚侏罗世接奴群和拉贡塘组火山岩断续分布于北冈底斯,晚侏罗世岩浆活动零星分布于沙莫勒一麦拉一洛巴堆～米拉山断裂以北。将冈底斯侏罗纪岩浆活动置于时空框架内分析发现,南冈底斯和北冈底斯在侏罗纪时主要受俯冲作用的影响．而冈底斯弧背断隆带和中冈底斯自早侏罗世以来除了受到俯冲作用的影响外,还受到自东向西逐步扩展的碰撞作用的影响。结合古地磁重建资料和其他新发现．认为冈底斯带侏罗纪这种岩浆活动的特点可用班公湖一怒江洋壳向南、新特提斯洋壳向北的双向剪刀式（剪刀口向西张开）俯冲模式来解释。     

华北克拉通东部早白垩世伸展盆地的发育过程及其对克拉通的破坏

在晚侏罗世华北克拉通东部破坏之初出现了区域性隆起,全区缺失上侏罗统沉积。在早白垩世早期,出现了区域性的伸展活动,断陷盆地形成,克拉通南、北缘伸展活动最强,北部燕山构造带以出现变质核杂岩为特征,南部出现宽裂谷型盆地。早白垩世中期华北克拉通东部普遍出现了火山活动与岩浆侵入。早白垩世晚期克拉通上以出现窄裂谷型盆地为特征,沿北北东走向的郯庐断裂带断陷活动最强。这些断陷盆地的演化过程揭示,经历地表抬升后,克拉通破坏之初的岩石圈热而弱,从而形成变质核杂岩或宽裂谷型盆地。这期间的破坏强度在空间上具有不均匀分布的特征,受控于早期岩石圈地幔的结构。经过早白垩世中期的大量岩浆活动之后,早白垩世晚期克拉通岩石圈温度降低、强度变大,从而利用早期大型断裂构造形成窄裂谷型盆地。这现象支持华北克拉通东部晚中生代的岩石圈减薄是以逐渐拆沉机制为主。     

北京云蒙山地区花岗岩穹隆及伸展构造的探讨

北京云蒙山花岗岩为一中生代侵入的花岗岩穹隆,花岗岩穹隆的叶理普遍发育,叶理轨迹基本平行于穹隆的外部边界,并显示出从核部到边部逐渐增强,东南侧明显强于西北侧的特点。变形构造研究显示,花岗岩穹隆的边部及围岩中普遍存在不同层次及不同运动方向的伸展构造。东南侧以具河防口－水峪伸展型韧性剪切带为特征,剪切运动标志显示为从ＮＷ－ＳＥ的正剪切运动,有限应变分析估算其剪切位移量在１０ｋｍ以上,剪切带上部被河防口正     

藏北安多地区侏罗纪菊石动物群及其古地理意义

藏北安多地区新发现2套以黑色页岩、深灰色钙质泥岩和泥灰岩为主的舍菊石化石的侏罗纪地层，它们与羌塘地区广泛分布的雁石坪群无论在化石组合或沉积特征方面都明显不同．岗尼乡剖面地层中产太阳菊石科的菊石，主要有Sonninia，Dorsetensia，Witchellia等。、这套地层是双湖地区色哇组的东延部分，时代确定为中侏罗世早中巴柔期114道班剖面中羌姆勒曲组的菊石化石大多归属于Virgatosphinctinae科，计有Aulacosphinctes、Virgatosphinctes等，均为上侏罗统菊石化石的典型分子，产出层位应归于提塘阶中、上部。藏北安多-改则以北一线的侏罗系深水黑色岩系虽不十分连续，但从有化石证据的土阿辛阶到巴柔阶再到提塘阶都有零星出露，它们同属一个沉积相区。侏罗纪时羌塘南部可能存在一套大陆边缘型沉积地层，因此有必要对该区的构造属性和演化历史重新进行解释。     

道虎沟生物群(前热河生物群)的发现及其地质时代

根据最新发现的动、植物化石 ,确立了“道虎沟生物群”,这一新的生物群属前热河生物群 ,生存时代大体相当于晚侏罗世的牛津期 (Oxfordian)至基末利期 (Kim meridgian)。这一发现大大补充了我国这一地质时期贫乏的化石记录 ,为探讨热河生物群的起源提供了较丰富的第一手材料。