A New Basal Neoceratopsian Dinosaur from the Middle Cretaceous of Jilin Province,China

A new basal neoceratopsian dinosaur, Helioceratops brachygnathus gen. et sp. nov., is described from the Quantou Formation （late Early Cretaceous or early Late Cretaceous） in the Liufangzi locality （Jilin province, China）. Helioceratops differs from other basal neoceratopsians with its deep dentary ramus, its steeply-inclined ventral predentary facet, its heterogeneous dentary crowns, and by the denticles and secondary ridges asymmetrically distributed on either side of the primary ridge on its dentary teeth. Along with Auroraceratops and Yamaceratops, Helioceratops represents one of the most derived non-coronosaurian neoceratopsians. The palaeogeographical distribution of basal neoceratopsians appears limited to northern China and southern Mongolia in the current state of our knowledge. It is therefore probable that this region constituted the birthplace for more advanced, Late Cretaceous Coronosanria.

Clay Minerals of the Middle Jurassic Through Lower Cretaceous in Guangyuan Area,Northern Sichuan:Implications to Paleoclimate

Clay mineral analyses of the Middle Jurassic through the Early Cretaceous sedimentary rocks from the Guangyuan-Jian’ge section,Sichuan Basin (southwestern China)were undertaken in this article, which is aiming to reconstruct the palaeoclimate of the area.Relative contents of the four clay minerals, smectite(25.8%-1.0%-46.8%),kaolinite(31.0%- 12.5%-12.6%),illite(31.3%-68.0%-28.0%)and chlorite(11.8%-8.5%-12.6%),as the target clay minerals,illite crystalline index(0.26-0.31-0.27)and chemical index(0.62-0.66-0.79)are used as indicator of paleoclimate.It is indicated that changes of

New Cretaceous Jehol Fossil Sheds Light on Evolution of Ancestral Mammalian Middle Ear

Ajoint research team led by Dr.MAO Fangyuan from the Institute of Vertebrate Paleontology and Paleoanthropology(IVPP)of the Chinese Academy of Sciences and Prof.MENG Jin from the American Museum of Natral History has reported a new multituberculate mammal,Sinobaatar pani,with well-preserved middle ear bones.The new mammal CO mes;from the Early Cretaceous Jehol Biota in Northeast China.Comparing three types of fossils with extant mammals at different embryological stages,the researchers identifed varlous evolutionary stages and ancestral phenotypes of the mammalian middle ear.

Late Jurassic-Early Cretaceous Erg Deposits in the Mengyin Basin, Western Shandong Province, China: Inferences about the Wind Regime and Paleogeography

The Late Jurassic-Early Cretaceous Santai Formation, sporadically distributed in western Shandong Province, comprises terrestrial alluvial-eolian successions, which records regional wind patterns and paleogeography in eastern North China. This paper conducts an analysis of eolian stratification, bounding surfaces, facies architecture and paleowind direction of the Santai Formation in the east of the Mengyin Basin, western Shandong Province. Three basic types of eolian stratification are recognized in the Santai Formation, including grainflow strata, wind ripple strata and adhesion strata, and have been grouped into eolian dune and interdune facies associations. The occurrences of reactivation surfaces and superimposition surfaces within eolian dune deposits indicate active compound dunes or draas. The association of adhesion strata with grainflow or windripple strata is the development of a wet eolian system. Cross-strata dip direction indicates different paleowind directions from the lower to the upper part of the Santai paleoerg. The lower part of the paleoerg was characterized by paleowinds blowing from northwest to northeast, whereas the upper part was under the influence of paleowinds consistently towards east to northeast. The identified changes in wind directions possibly suggest wind regime shifts from monsoon circulation to westlies of planetary wind system, which may be related with the collapse of the East China Plateau during the Late Jurassic to Early Cretaceous.

A New Species of Aetheogrammatidae(Insecta:Neuroptera)with a Preserved Proboscis from the Lower Cretaceous of NE China

Objective The Aetheogrammatidae is a small family of extinct Neuroptera,which comprises six species in five genera,described from the Middle Jurassic to the Lower Cretaceous of China and Kazakhstan.They are easily distinguishable due to their highly derived venation with apical portion of R1 branched in the manner of Rs.

塔里木盆地库车坳陷英买力地区白垩系巴什基奇克组中深层砂岩储层孔隙保存机制

塔里木盆地库车坳陷南部斜坡带英买力地区白垩系巴什基奇克组砂岩储层物性好,油气勘探潜力大,但其非均质性强、油气分布规律不明。综合利用岩心观察、系列薄片(普通、铸体、阴极发光及包裹体)、扫描电镜、物性测试和X射线衍射等分析测试资料和成岩过程重建与物性恢复技术,分析英买力地区中深层巴什基奇克组砂岩储层的岩性与物性,探寻其孔隙特征与保存机制,划分储层类型和明确有利储层分布规律及控制因素。该砂岩主要为长石岩屑砂岩和岩屑长石砂岩,杂基含量较低,其成分和结构成熟度均中等;储层孔隙类型主要为残余原生孔隙,其次为次生孔隙,主要为粒间溶孔和粒内溶孔,为中高孔—中高渗储层。巴什基奇克组中深层砂岩原生孔隙得以保存主要在于其形成的沉积环境与经历的成岩和成储演化:首先砂岩形成于高水动力的辫状河三角洲前缘水下分流河道微相,不断叠置的河道形成了厚度较大且分布稳定的水道复合砂体,强水动力使得砂岩碎屑颗粒含量高、分选较好,为原生孔隙形成提供了物质基础;其次早期长期浅埋和后期快速深埋的埋藏演化方式使砂岩经历了较弱的压实作用改造,同时晚期深层超压作用大大增强了砂体抗压实能力,残余原生孔隙得以保存;最后坳陷不断降低的古地温梯度使得残余原生孔隙得以有效保存。

伊拉克地区中上白垩统滩相灰岩颗粒组成特征及其对沉积环境的指示

伊拉克地区白垩系广泛发育滩相灰岩储层,由于这类灰岩储层的颗粒类型复杂导致沉积相划分和预测难度较大。前人的研究结果发现,伊拉克地区中上白垩统主要发育似球粒、绿藻、棘皮,其次为有孔虫、圆笠虫、内碎屑。针对该地区中上白垩统开展不同颗粒的类型及其组合对沉积环境的指示有助于进一步厘清沉积微相和储层类型。该研究利用岩心和薄片观察,识别出了不同类型的颗粒,明确了中上白垩统Kh2层、Mi4层和Ma1层的颗粒类型。绿藻、薄壁瓣鳃类生物反映正常盐度海水或广盐度的浅海相对局限且水体能量较低的环境;有孔虫类中圆笠虫为移动底栖,分布范围广,反映水动力强;厚壳蛤这类厚壁瓣鳃类和内碎屑形成于浅海高能环境;棘皮类对沉积环境无选择性,分布范围广,各个层位中均可见。对中上白垩统典型层位不同颗粒类型的认识为我国在伊拉克地区油气开发和油气储层研究提供了岩相学依据。

Upper Jurassic and Lower Cretaceous of Sanjiang-Middle Amur basin: Non-marine and marine correlation

A comparative analysis of Late Jurassic-Early Cretaceous strata have been done for the Sanjiang Middle Amur basin, a coaland oil-bearing area spanning the eastern Heilongjiang of northeastern China and southeastern Far East of Russia. On the basis of various fossils occurring in the formations, particularly by means of the Tithonian-Valanginian index Buchia and the late Barremian-middle Albian indicator Aucellina assemblages, the marine and non-marine Late Jurassic-Early Cretaceous strata in the basin are correlated. The Mesozoic international chronostratigraphic chart (http://www.stratigra phy.org) is established basically based on the marine rocks. To accurately date the non-marine strata, it is necessary to correlate them with the marine deposits. This study sheds new light on the dating and correlation of non-marine Upper Mesozoic. Additionally, the results would help understand the tectonics and paleogeography and thus aid the exploration of energy resources.

Dinosaur diversity during the transition between the middle and late parts of the Late Cretaceous in eastern Shandong Province,China:Evidence from dinosaur eggshells

The record of dinosaur eggs from the Upper Cretaceous Wangshi Group in eastern Shandong Province,China shows that the dinosaur species represented by elongatoolithids were present from the middle to the late Late Cretaceous,whereas those represented by the dictyoolithids and spheroolithids became extinct in the middle Late Cretaceous and the new species represented by ovaloolithids appeared in the late Late Cretaceous.Estimated eggshell conductance of water vapor is over 4 to over 115 times higher in spheroolithids and the dictyoolithids than in elongatoolithids and ovaloolithids,indicating that eggs of the first two oofamilies required higher humidity during incubation.Based on the18O record as preserved in eggshell,a change from relatively humid to relatively dry climatic conditions can be assumed to have taken place during the transition between the middle and late parts of the Late Cretaceous.It is reasonable to suggest that the change in climate was the cause of the dinosaur diversity.

庐山岩浆核杂岩隆起-快速伸展变形特征和时代

华南板块中东部晚中生代广泛发育伸展构造变形事件,不仅发育沉积红盆、伸展穹窿、变质核杂岩、韧性拆离断层带等,也发育大规模的同构造岩浆和成矿作用,但是快速伸展时限仍然存在争议。选取庐山岩浆核杂岩,针对岩浆核杂岩两侧的晚中生代韧性剪切带及周缘开展野外地质调查及同构造变形分析。构造变形的运动学解析结果表明,庐山岩浆核杂岩拆离正断层的伸展方向为NW-SE向,同构造40 Ar-39 Ar测年获得白云母主坪视年龄为105.20±0.23 Ma和黑云母主坪视年龄95.84±0.09 Ma,限定了庐山岩浆核杂岩隆升-快速伸展时限集中于95~105 Ma。庐山岩浆核杂岩本期伸展构造变形特征及形成时代与华南板块区域性的隆升-伸展变形特征一致,代表了华南板块晚中生代以来快速的伸展构造变形事件,形成机制可能与古太平洋板块向华南板块俯冲后的板块弯转后撤有关。

内蒙古中东部玛尼吐组火山岩形成时代及其大地构造环境

玛尼吐组广泛分布在内蒙古中东部地区,长期以来与满克头鄂博组和白音高老组的地质时代被定为晚侏罗世,然而前人在玛尼吐组中发现Nestoriapissovi化石,并认为是早白垩世冀北阶的带化石,同位素年代学结果差异也较大,而且形成的大地构造环境仍然存在争论。因此,笔者对玛尼吐组火山岩进行了同位素年代学分析,并利用全岩成分探讨其形成的大地构造环境。玛尼吐组采集的3个安山岩和粗安岩的锆石U–Pb(LA–ICP–MS)测年结果分别为(142.4±1.4)Ma、(130.0±1.4)Ma和(145.0±1.5)Ma,显示该地区玛尼吐组形成于早白垩世。样品SiO2含量为59.43%~64.73%,Al_(2)O_(3)含量为15.66%~17.19%,K_(2)O含量为2.56%~5.03%,Na_(2)O含量为3.59%~4.53%,全碱含量为6.36%~9.56%;微量元素以富集大离子亲石元素和LREE,亏损Nb、Sr、P和Ti为特征;稀土元素ΣREE=118.71×10^(–6)~189.99×10^(–6),轻重稀土分馏系数(La/Yb)N为8.88~9.58,δEu值为0.66~0.95,Eu负异常,与岛弧火山岩地球化学特征相似。对比大兴安岭西部玛尼吐组西部、中部(~140 Ma)和东部火山岩年龄,笔者认为其玛尼图组火山岩类最老形成于晚侏罗世(~158 Ma),向东逐渐变新为早白垩世(140~130 Ma),这一变化与蒙古–鄂霍次克洋自西向东的闭合及陆块的后碰撞伸展有关。

乍得Doseo盆地白垩纪沉积充填演化及对油气成藏的控制作用

通过综合分析地震及钻井资料,阐述了Doseo盆地的区域地质特征、盆地结构及沉积体系特征,确定了Doseo盆地幕式裂谷演化过程及反转改造特征。重点分析了Doseo盆地自早白垩世以来的沉积充填演化特征,认为盆地经历了早白垩世Neocomian-Barremian期的张性断陷、Aptian-Albian期的走滑—拉分断陷及晚白垩世—新近纪的广覆式坳陷三个发育阶段,形成了明显的下部断陷、上部广覆式坳陷的双层沉积充填结构,但盆地以早白垩世的张性及走滑—拉分断陷沉积充填为主,形成了广泛分布的湖相烃源岩及水下扇、三角洲前缘沉积储层,是盆地的主要勘探目标。Doseo盆地湖相沉积地层主要发育在早白垩世的张性及走滑—拉分断陷阶段,而且是一个快速湖泛过程,广泛发育退覆式三角洲沉积。早白垩世晚期在北部撒哈拉地台挤压作用下湖盆快速抬升消亡,晚白垩世—新近纪充填了河流相的粗碎屑沉积,在断陷活动中盆地缺乏旋回性湖相地层的发育过程。Doseo盆地下白垩统整体表现为“北部水下扇”、“南部短轴浅水三角洲”及“东北部长轴深水三角洲”的沉积体系分布格局。在构造—沉积作用的共同控制下,Doseo盆地陡坡带近岸水下扇及缓坡带三角前缘发育较好的储盖组合,是油气勘探较有利的沉积相带,已经发现了多个油气藏。同时盆地后期的构造反转也为陡坡带水下扇砂体及中部湖底扇沉积等岩性圈闭目标成藏提供了机会,是盆地主要的新勘探领域。

Late Jurassic-Early Cretaceous tectonic switching in Liaodong Peninsula of the North China Craton and the implications for gold mineralisation

Constraining the processes of deformation during tectonic switching from compression to extension is difficult because of the scarcity or absence of associated sedimentary and magmatic rocks and weak metamorphism.The east margin of the eastern North China Craton experienced Early to Middle Jurassic compression and Early Cretaceous extension.However,the period of tectonic quiescence lasting~13 million years(between 153 and 140 Ma)during which this transition occurred is poorly understood.This paper reports the identification of small-scale N-S-trending thrust and sinistral strike-slip faults(TSS)and NWtrending thrust and dextral strike-slip faults(TDS)in the Tongyuanpu-Aiyang region,which is part of the northern Liaodong Peninsula.Calculation of the tectonic stress field using striations,fault planes and kinematics reveals a NW-SE-oriented maximum principal axis(σ1),and sub-horizontalσ2 andσ3.Assemblages of N-S-trending TSS and NW-trending TDS were arranged with right stepping and resulted in local uplift and erosion at the junctions between fault terminations,which partitioned the Early and Middle Jurassic basins into residual smaller volcanic-sedimentary basins.These basins were unconformably overlain by small Early Cretaceous volcanic-sedimentary basins,such as those at Tongyuanpu and Fangjiaweizi.Magmatic ages and the timing of basin formation constrain the initiation of tectonic switching to 156–153 Ma,and its termination to 140–139 Ma.We suggest that R-R’Riedel shears controlled the formation of the N-S-trending TSS and NW-trending TDS.The R-R’shears were produced by continued sinistral strike-slip and northward growth along the Bohai Bay segment of the Tan-Lu fault zone during the Late Jurassic to early Early Cretaceous,simultaneous with a gradual weakening in the tectonic stress field during a switch in the direction of subduction of the Palaeo-Pacific plate from NW-ward to NNW-ward.This tectonic switching might have promoted the dissolution of gold and migration of gold-bearing fluids.

河南省花冲建筑用机制砂矿床地质特征与成因研究

我国普通建设用砂矿产资源十分丰富。近年来,随着社会建设规模的持续扩大上升等因素,导致建筑材料目前远不能满足经济发展的需求。因此加强建设用砂矿产资源勘查和开发利用十分必要。河南省唐河县花冲建筑用机制砂矿床位于秦岭复杂构造带东段,桐柏—大别隆起西部,南阳断陷盆地东缘。交通条件优越,区位优势明显。通过对其矿床地质特征与成因研究,得出如下结论,矿床赋存于中生代白垩世二长花岗岩体中,由燕山期酸性岩浆侵入冷凝形成的高温熔融体冷凝结晶矿床。区内岩浆的侵入作用为机制砂的形成提供了至关重要的物质基础,后期的构造隆起作用使得本区地壳上升,局部出露地表,呈现剥蚀与上升二者动态平衡的状态。为机制砂的开发利用提供了得天独厚的条件;矿石自然类型为细—中粗粒二长花岗岩,工业类型为建筑用机制砂,矿石坚固性为Ⅱ类,压碎指标为Ⅲ类,综合评定矿区内矿石品级为Ⅲ类,属中砂。矿区内资源量可靠;区域中生代中酸性侵入岩广泛发育,具有良好的建筑用花岗岩找矿远景。对于该矿床的研究,可进一步推动该区建筑材料工业的发展,缓解其周边区域对建筑材料的需求,促进地方经济。

波斯湾盆地中白垩统Mishrif组碳酸盐岩储层特征及其发育模式

Mishrif组碳酸盐岩储层是波斯湾盆地最主要的储集层之一,储层岩石类型主要为礁滩相生物礁灰岩、生屑灰岩和含生屑泥灰岩,储集空间主要为粒间(溶)孔、晶间(溶)孔、铸模孔、表生期组构选择性溶蚀孔洞和基质微孔。储层多呈层状展布,横向上连续,边界受沉积相带约束;纵向上发育多套致密隔夹层,呈强非均质性。储层发育与保存主要受沉积作用、成岩作用和构造作用影响。碳酸盐岩缓坡背景下发育的生物礁和生屑滩空间分布受盆地基底古构造格局控制,是优质储层分布相带。相对海平面升降旋回控制相带迁移和成岩作用差异,导致优质孔渗层与致密隔夹层交互发育。构造圈闭发育与油气充注时间的耦合有效抑制压实作用和胶结作用对储层的破坏,是储层得以保存的有利因素。

冈底斯中北部晚侏罗世—早白垩世地球动力学环境:火山岩约束

利用新近完成的1∶25万区域地质调查资料和笔者分析数据,初步研究了西藏冈底斯带晚侏罗世—早白垩世火山岩的分布特点及地层古生物、同位素年代学约束的火山活动时代以及冈底斯中北部火山岩的性质、构造环境、岩石成因和俯冲极性。冈底斯带晚侏罗世—早白垩世火山岩主要分布于南冈底斯、中冈底斯、北冈底斯和班公湖-怒江缝合带南缘,基本同期开始于早白垩世(大约120～130 Ma)并可能延续到晚白垩世,以冈底斯中北部地区规模最大为特征。已有数据显示中冈底斯则弄群火山岩包括部分中钾钙碱性系列的中基性岩石和占优势的高钾钙碱性系列的中酸性火山岩,不同于传统岛弧火山岩,但与中安第斯厚地壳背景下的岛弧火山岩相似,北冈底斯主要为与传统岛弧火山岩相似的中钾钙碱性系列火山岩。中冈底斯则弄群中基性火山岩很可能与来自消减沉积物和/或蚀变玄武质洋壳的含水流体引起上覆地幔楔物质的部分熔融有关,并在岩浆上升过程中经历了明显的分离结晶作用和中上部地壳物质的同化混染(即AFC过程),长英质火山岩很可能主要与地壳重熔有关,但并不能完全排除镁铁质岩浆的分离结晶作用。目前冈底斯中北部晚侏罗世—早白垩世火山岩地球化学数据揭示的成分变化、地壳厚度、与俯冲带的距离以及冈底斯带同期火山岩的分布特点暗示冈底斯中北部火山岩很可能与班公湖-怒江特提斯洋壳向南的俯冲作用有关。

伊拉克艾哈代布油田中-下白垩统碳酸盐岩储层孔隙结构及控制因素

伊拉克艾哈代布油田中-下白垩统碳酸盐岩储层孔隙结构类型划分及其差异性的受控因素和成因的认识是制约该类储层分类评价的一个关键问题。本文综合运用了常规薄片、铸体薄片、扫描电镜、电子探针、常规物性、压汞分析、阴极发光、稳定同位素分析等手段及统计分析方法对储层的主要孔隙类型、喉道类型、喉道分布类型进行了研究,并在此基础上确定了高孔中渗细喉型、中高孔低渗细喉型、中高孔特低渗微喉型、低孔特低渗极微喉型四种孔隙结构类型及其划分依据和方案,同时指出了在该类储层中好的孔隙结构具有网络状、偏细型、分选较差的孔喉特征。通过分析明确了孔隙结构差异性的主要控制因素为岩石组构和溶蚀作用,认为该套储层的孔喉空间及结构是以沉积形成的原生孔隙受同生期或准同生期的溶蚀改造为基础,并在后期表生岩溶作用下的改造而成;而先期受岩石组构控制下的溶蚀作用控制了储层孔隙结构的差异性。通过本文研究将对中东地区该类储层的形成及分类评价研究具有较好的指导意义。

山东中侏罗世-早白垩世侵入岩的锆石Hf同位素组成及其意义

对山东中侏罗世-早白垩世侵入岩中锆石的原位Hf同位素分析显示,形成于晚太古代(上交点年龄～2.5Ga)的继承锆石具有正的ε_(Hf)(t)值(+8～+1),Hf同位素模式年龄集中在2.6～2.8Ga,与辽宁古生代金伯利岩中基性下地壳捕虏体中锆石Hf组成和Hf模式年龄十分一致,Hf模式年龄也与研究区变质岩和花岗岩的全岩Nd模式年龄相同,因此,这些继承锆石来自于晚太古代由岩浆底侵形成的基性下地壳。新生锆石出现在继承锆石周围或者以独立颗粒出现,其U-Pb年龄为177Ma和132～126Ma,ε_(Hf)(t)值均为负值(-23～-1)。山东中生代侵入岩的形成与富集岩石圈地幔,亏损地幔和地壳三个端员之间的相互作用有关。其中根据来源于晚太古代下地壳的侏罗纪铜石二长花岗岩限定的研究区下地壳ε_(Hf)(t)平均值为-20,根据来源于富集岩石圈地幔的早白垩纪沂南辉长岩限定的富集地幔端员的ε_(Hf)(t)为-16。部分样品锆石ε_(Hf)(t)变化非常大(-20～-1),示踪了岩浆作用过程中亏损地幔物质的参与程度的逐渐增强。这种变化是华北晚中生代岩石圈大规模减薄作用的结果。

伊拉克哈勒法耶油田中、上白垩统碳酸盐岩储层岩石类型及特征

伊拉克哈勒法耶油田中、上白垩统碳酸盐岩储层是重要的产油层系。综合利用岩心、薄片、物性测试、压汞数据及扫描电镜分析资料,以典型取心井为研究对象,开展研究区岩石类型及特征研究。结果表明,岩石矿物成分主要为方解石和泥质,局部含少量白云石。岩石组分多样,各组分相对含量差异明显。在岩石组分类型及特征研究基础上,以泥晶基质、有孔虫骨架和生屑/砂屑为三端元,提出研究区岩石类型划分方案。将研究区岩石划分为泥晶灰岩、有孔虫灰岩和生屑/砂屑灰岩3大类,并进一步根据颗粒含量的多少将岩石类型划分为9小类。不同岩石的孔隙类型、孔隙结构和物性特征均不相同,是不同沉积环境的产物,储集性能差异较大。总体来看,平面上不同岩石类型分布明显受沉积环境控制。纵向上,有孔虫灰岩集中分布在上白垩统碳酸盐岩储层,厚度较大,生屑/砂屑灰岩分布较为局限,中白垩统碳酸盐岩储层多为生屑/砂屑灰岩。泥晶灰岩以薄层状分布在生屑/砂屑灰岩之间,有孔虫灰岩类罕见。

西藏中白垩世和始新世岩相古地理

西藏中白垩世海相区可以识别出9种沉积相类型6个相组合带，老第三纪时可以鉴别出约5种岩相类型4个相组合带。建议将这些岩相组合带视为对应的海相次级地层分区。拉萨地体和羌塘地体在白垩纪中期海水分布可能继承了侏罗纪时的格局，并进一步扩展到了羌塘地体的南部和中部；与此同时，拉萨地体主体和特提斯喜马拉雅仍然被海水淹没，与全球同期海侵事件表现一致。