闽西下白垩统坂头组锆石U-Pb年龄及地层对比

通过闽西地区永安盆地与崇安盆地下白垩统坂头组凝灰岩夹层中的岩浆锆石定年研究以及古生物研究,首次获得2个盆地坂头组底部开始沉积的准确年龄,分别为（144±2）和（116±2）Ma。根据它们与上覆地层关系来看,2个盆地坂头组顶部年龄基本等时约为100 Ma。因此,崇安盆地坂头组仅相当于永安盆地吉山剖面上段。在与临区地层对比...     

福建永安坂头组植物及古气候分析

分析了福建永安盆地早白垩世坂头植物群的组成特征。共计报道该植物群化石24属52种左右,包括未定种以及存疑种21个。植物群的组成以具鳞片状叶的松柏类化石为主,苏铁类化石次之,并以本内苏铁目占绝对优势,然后是真蕨类化石,以小羽片小而质厚为特征,银杏化石及其少见,未发现被子植物。坂头组植物的组成面貌与欧洲Wealden植物群、日本外带领石植物群,以及我国南方植物区,如浙江、山东等地的早白垩世植物群比较一致,说明坂头组含化石层位年龄为早白垩世早期。坂头组大多数植物主要分布于热带或亚热带地区,具有耐干旱炎热的特点,反映了较干旱而炎热的气候特征。除此之外,还发现少量适宜生活在温凉潮湿气候环境下的植物。根据这些对气候具有指示意义的代表分子在坂头组中的数量以及分布情况,推断永安盆地早白垩世早期气候总体上比较干旱炎热,且伴随有不同程度季节性的潮湿。     

福建永安下白垩统坂头组枝脉蕨属一新种Cladophlebis yonganensis sp.nov.

对福建永安市下白垩统坂头组保存较好的真蕨类营养叶化石枝脉蕨Cladophlebis进行了叶片形态及角质层微细构造特征的分析, 该化石至少二次羽状分裂, 末二次羽轴粗, 小羽片小, 全缘, 排列紧密, 中脉明显, 侧脉密集, 多数一次分叉; 上表皮无气孔器, 细胞轮廓不清晰, 偶见表皮毛; 下表皮具气孔器, 呈纵向带状排列; 表皮细胞长方形或呈条带状; 垂周壁加厚, 较直; 平周壁波状突起; 气孔器近圆形, 具明显拱盖, 保卫细胞弱角质化, 副卫细胞分化不明显.对当前化石小羽片解剖学特征的分析填补了该属植物化石叶片角质层微细构造特征的空白, 进一步将其与现生紫萁Osmunda joponsica以及部分真蕨类化石的表皮特征进行对比, 结合宏观形态和角质层特征的分析及其与相似种类的比较, 将永安的标本命名为一新种, 永安枝脉蕨Cladophlebis yonganensis Dai et B. N. Sun, sp. nov., 并且推断当前化石代表了某一类已经灭绝的真蕨类植物.      

内蒙古鄂尔多斯盆地下白垩统罗汉洞组剑龙类化石新材料

鄂尔多斯盆地下白垩统志丹群产出丰富的四足类动物化石:龟类、离龙类、鳄形类、鹦鹉嘴龙类、剑龙类、甲龙类、兽脚类、鸟类和早期哺乳类。采自内蒙古杭锦旗老龙豁子志丹群罗汉洞组剑龙类关联的荐椎与肠骨化石新标本,其形态特征显示该标本可被归为鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis)。该标本解剖学研究表明,鄂尔多斯乌尔禾龙腰带还具有以下特征:上髋臼面前缘向后凹而后缘内侧更加内凹。鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis)和新疆准噶尔盆地的平坦乌尔禾龙(Wuerhosaurus homheni)在腰带上存在明显区别:(1)鄂尔多斯乌尔禾龙肠骨前突延伸较短,肠骨前突背缘向后逐渐向背侧拱曲、高度逐渐加大,而平坦乌尔禾龙肠骨前突后端背腹缘大致平行;(2)鄂尔多斯乌尔禾龙上髋臼面较小;(3)鄂尔多斯乌尔禾龙左右肠骨前突延伸方向与中轴线之间的夹角略小于平坦乌尔禾龙。这些区别进一步表明,鄂尔多斯乌尔禾龙和平坦乌尔禾龙是不同的种。     

论福建坂头组的时代及对比

<正> 坂头组系陈恺(1943)命名,未指定建组剖面,以永安城北坂头村一带的岩性为标准。当时称坂头系,时代为早白垩世。坂头组分布在崇安、永安和泰宁举岚等盆地,宁化、安溪、仙游、古田和霞浦等地亦有零星出露。对坂头组的时代归属存在二种意见:福建省区调队(1976—1985)、原福建石油地质队(1978)、顾知微(1980、1982)、王思恩等(1985)归于     

辽西下白垩统义县组湖相碳酸盐岩及其沉积环境研究

辽西地区下白垩统义县组是热河生物群产出的主要地层,其中产出大量精美的生物化石,但是由于受到后期构造破坏和风化作用影响,难以开展野外工作,热河生物群产出的古地理环境及盆地沉积环境的研究程度仍然较低。该组地层中湖相碳酸盐岩比较发育,本次工作主要对辽西义县组老公沟—金刚山剖面4个沉积层中产出的多层湖相碳酸盐岩沉积层进行了深入研究。通过野外工作结合室内镜下鉴定,分析了义县组湖相碳酸盐岩的产出状态和岩石类型,划分出5个岩相类型和两个相组合。结合野外实测剖面中碳酸盐岩与其它沉积岩层的组合关系对义县组湖相碳酸盐沉积环境进行了探讨,发现义县组湖相碳酸盐岩主要为洪水—漫湖沉积体系中较浅的储水洼地和滨浅湖半咸水沉积环境,并建立了义县组湖相碳酸盐岩沉积相模式。     

松辽盆地四五家子油田下白垩统泉头组沉积相研究

松辽盆地四五家子油田位于吉林省公主岭市内，在构造上是松辽盆地东南隆起区杨大城子背斜的一部分。油田的储层主要由下白垩统泉头组组成，它是在晚白垩世干旱和氧化环境中沉积的。其物源来自东北部的中央古隆起。本区储层岩性以岩屑长石砂岩为主，部分为岩屑质长石砂岩和长石质岩屑砂岩。通过单井相分析，主要相标志为具有牵引流沉积机制为主的沉积构造和粒度分布特征。根据相标志分析，储层为曲流河相沉积，发育曲流河点坝、决口扇、天然堤及泛滥平原四种沉积微相类型。曲流河相自下而上为点坝-天然堤-决口扇-泛滥平原的正韵律组合。在建立各沉积微相测井相模式的基础上，对全区136口非取心井进行了沉积微相识别，而应用顺序指示模拟实现了沉积微相的平面展布，恢复其古地理面貌：主要发育两条自北北东向南南西方向延伸的曲流河道，具有河道点坝特征的泉头组6、7小层是主要的储集层。这个研究成果为下一步油田开发奠定了基础。     

内蒙古固阳地区下白垩统研究新进展

在内蒙古固阳县以东下湿壕地区 1∶5万区域地质调查中 ,首次在前人划分的下白垩统固阳组 采到瓣腮类、腹足类、介形类、轮藻、植物等大量化石。结合地层沉积组合特征 ,将原固阳组重新厘定为下白垩统李三沟组。这一地层层位的厘定和古生物化石的发现 ,对进一步探讨固阳盆地的构造演化和成煤规律等都将具有重要的理论意义和实际价值     

辽西下白垩统义县组湖相碳酸盐岩中的燧石成因

辽西义县鹰窝山下白垩统义县组砖城子层中部发育一套湖相碳酸盐岩,可识别出4种岩相类型,其中角砾化团块灰岩相中含有大量燧石,所含的燧石可据形态划分为结核状、透镜状和团块状3种类型,据颜色和透明度识别出两种类型。燧石以微晶石英和玉髓为主,含少量的白云石和方解石晶粒。该岩相系相对干旱气候背景下的洪积-漫湖沉积体系中较浅储水洼地沉积,火山活动也具一定的影响力。     

内蒙古固阳地区下白垩统研究新进展

在内蒙古固阳县以下湿壕区１：５万区域地质调查中,首次在前人划分的下白垩统固阳组采到瓣腮类、腹足类、介形类、轮藻、植物等大量化石。结合地层沉积组合特征,将原固降组重新厘定为下白垩统李三沟组。这一地层层位的厘定和古生物化石的发现,对进一步探讨固阳盆地的构造演化和成煤规律等都将具有重要的理论意义和实际价值。     

福建永安白垩纪红层盆地丹霞地貌及特征

永安白垩纪红层盆地位于福建省中部永安市东隅,大地构造处于华夏古陆武夷隆起的西南部,盆地内晚白垩世崇安组紫红色厚层一巨厚层砾岩、砂砾岩经内、外动力地质作用,发育峰丛、石峰、石堡、石墙、石柱等正地貌和线谷、巷谷、峡谷、峡谷曲流等负地貌,构成风光旖旎的丹霞地貌景观。永安红层盆地丹霞地貌于上新世开始发育,现已处于中年期发展演化阶段,是开展中年期丹霞地貌旅游和科考的宝贵地质遗迹。     

甘肃酒西盆地早白垩世两种Elatides化石微细构造

现已绝灭的古老松柏类植物似纵属Elatides在中生代北半球中高纬度植被组成研究上具有重要意义。甘肃酒西盆地早白垩世地层中发现了Elatides的营养枝和雌球果,并保存有较好的碳膜,对它们进行了详细的宏观形态和微细特征研究。根据营养枝、叶角质层、花粉、球果、苞鳞和种子的特征,鉴定这些化石为2个种：Elatides harrisii Chow和Elatides curvifolia (Dunker) Nathorst。其中：Elatides harrisii的突出特征是,花粉球形且具乳状小突起、表面光滑无纹饰,侧面观具褶皱;Elatides Curvifolia的显著特点为,着生于苞鳞腹面基部的种鳞先端三裂,具三枚胚珠。这些特征与现生杉木Cunninghamia非常相似,推论Elatides与现生Cunninghamia可能具有亲缘关系。通过对Elatides地质历史和地理分布的研究,发现该属的演化方向与中生代大陆漂移的方向具可比性,因而为板块构造学说提供了又一古生物学佐证。     

Sauropod Teeth from the Lower Cretaceous Luohandong Formation of Ordos Basin, Inner Mongolia

The Early Cretaceous Zhidan Group in the northern Ordos Basin, Inner Mongolia, yielded a large number of tetrapods, including turtles, choristoderes, crocodyliforms, psittacosaurs, stegosaurs, theropods and birds. Well-preserved sauropod teeth have been found in the Luohandong Formation, a middle-upper unit of the Zhidan Group. The large V-shaped wear facet, low slenderness index value, labial grooves, lingual ridge and concavity on the tooth crown suggest that these teeth are from titanosauriforms. Moreover, the presence of the prominent bosses on the lingual side of the tooth crown indicates these teeth should be identified as Euhelopus teeth further. The existence of Euhelopus in Ordos Basin (Inner Mongolia), Shandong Province and western Liaoning Province shows some connections about vertebrate faunas during Early Cretaceous in these areas. Other tetrapod groups such as turtles (Sinemys, Ordosemys), choristoderes (Ikechosaurus), psittacosaurs (Psittacosaurus) and birds (Cathayornis) provide more evidences for this viewpoint.     

吉林延边地区早白垩世长财组的蕉羽蕨叶(Nilssoniopteris)

首次在吉林省延边地区长财煤矿早白垩世长财组发现蕉羽蕨叶属(Nilssoniopteris)。根据其外部形态及表皮构造等特征,鉴定并描述蕉羽蕨叶4个种,即：普里纳达蕉羽蕨叶Nilssoniopteris prynadae Samylina,平轴蕉羽蕨叶(新联合)N.platyrachis (Samylina) comb．nov．长叶蕉羽蕨叶?N.longifliadenko?和蕉羽蕨叶(未定种)Nilssoniopteris sp。     

Saurischian track assemblages from the Lower Cretaceous Shenhuangshan Formation in the Yuanma Basin,Southern China

Cretaceous dinosaur tracks from Hunan Province are historically significant as the basis for three ichnotaxa: Xiangxipus chenxiensis, Xiangxipus youngi, and Hunanpus jiuquwanensis all representing theropodan tracks, described from a single site in 1982. Although the type locality has since been destroyed, the type specimen and replicas remained available for restudy in 2006, when paratype Hunanpus tracks and sauropod footprints were described from a second, nearby locality. Material from both localities is here re-described in detail. It is proposed that while Xiangxipus chenxiensis can be regarded as a distinct ichnospecies, probably representing an ornithomimid trackmaker, Xiangxipus youngi cannot be accommodated in the same ichnogenus. We consider it similar to the ichnogenus Wupus from the Lower Cretaceous of Sichuan Province, and therefore of possible avian affinity. We also find no justification for regarding Hunanpus jiuquwanensis as generically distinct from the widespread ichnogenus Grallator, and therefore rename it Grallator jiuquwanensis comb. nov. The Hunan track record is generally consistent with the sparse record of theropod skeletal remains in the province, but adds evidence of sauropods that was previously lacking.     

The longest theropod trackway from East Asia,and a diverse sauropod-, theropod-, and ornithopod-track assemblage from the Lower Cretaceous Jiaguan Formation,southwest China

Here we report a large dinosaur tracksite from an extensive fluvial sandstone surface in the Lower Cretaceous Jiaguan Formation of Sichuan Province, China. The site contains over 250 individual tracks comprising at least 18 recognizable trackways, including the longest theropod trackway (cf. Eubrontes) known from China. This exceptional theropod trackway consists of 81 successive footprints covering a distance of 69 m. The tracks are well-preserved and are expressed both as true tracks on the main “upper” surface and as transmitted undertracks on a locally exposed “lower” bed. Also recorded are six other theropod trackways, including small Grallator-like ichnites, eight sauropod trackways (cf. Brontopodus), and three small ornithopod (cf. Ornithopodichnus) trackways with a parallel orientation, which may indicate gregarious behavior. Several trackways of a larger theropod trackmaker show pes imprints with elongated traces of the metatarsals, suggesting extramorphological (substrate-controlled) variation and/or plantigrade posture, which is here interpreted as indicating a change in gait assumed in response to deep and soft sediment. The assemblage indicates a diverse dinosaur fauna in the Lower Cretaceous Sichuan Basin with variously sized theropods, sauropods, and ornithopods. The late occurrence of footprints of the Grallator-Eubrontes plexus in Lower Cretaceous strata is further evidence of the extended stratigraphic range of this morphotype and the distinct palaeobiogeographic distribution of these trackmakers in East Asia.     

A new species of Leptotarsus (Diptera: Tipulidae) from the Lower Cretaceous Crato Formation of Brazil

Leptotarsus (sensu lato) lukashevichae sp. nov. is described and illustrated, based on a single but very well preserved female specimen from the Crato Formation of Brazil (Aptian, ca. 112 Ma). Along with other Leptotarsus species recently described from Lower Cretaceous beds of Brazil, Spain, Russia and China, this new species is among the oldest known records of the genus Leptotarsus and the family Tipulidae.