由恐龙化石论晚白垩世事件沉积

本文根据晚白垩世恐龙化石的分布结合地层学特征,初步提出了这套含有恐龙化石的晚白垩世地层属于事件沉积的观点,并认为导致这次事件沉积的原因可能是由天体撞击地球产生的强海啸形成。     

广东长坑金银矿床硅质岩中的放射虫化石及生物化石残迹

在广东长坑金银矿床的主要含金岩石碳质硅质岩巾两次找到放射虫化石,其时代可能属于早石炭世。在这些碳质硅质岩中还发现一些生物化石残迹．如石英环、石英圈、石英单晶球、石英多晶球、生物残体和似生物结构。由此认为碳质硅质岩原来含有一定量的微体生物化石．形成于海盆环境,应属沉积成因,这是证明碳质硅质岩属于热水沉积成因而不属于热液蚀变交代成因的有力证据;也表明热水沉积过程有生物物质的加入,热水沉积和生物沉积可以混合发生,说明长坑金银矿床形成手张性、不补偿、水较深的盆地之中。对长坑盒银矿床的矿区含矿地层应泼归属的岩石地层单位提出了疑问。     

柴达木盆地北缘沉积凝灰质岩层段的地层时代

柴达木盆地北缘深部沉积凝灰质岩层段的地层归属存在2种观点,下侏罗统和石炭系。本文通过岩石薄片、微量元素、孢粉组合以及海相化石碎片等多种资料的综合分析,认为沉积凝灰质岩层段与其上的下侏罗统之间岩性、电性出现突变的主要原因是沉积时火山事件以及晚期方解石脉充填造成的,并不能代表下伏的老地层;沉积凝灰质岩层段的海相化石碎片为搬运再沉积的结果,没有地层指示意义;孢粉组合能反映沉积凝灰质岩层段沉积的地质年代,据此确认沉积凝灰质岩层段为下侏罗统湖西山组二段。     

准噶尔盆地晚白垩世介形类化石组合北大核心CSCD

对准噶尔盆地晚白垩世地层的岩性特征、沉积环境、厚度变化及分布规律进行了讨论.这套红色地层在不同时期、不同地段分布范围和沉积厚度变化较大,岩性单一,环境单调,生物化石较贫乏,但介形类化石很典型,表现出晚白垩世化石组合特征,建立了3个介形类化石组合,为准噶尔盆地晚白垩世地层划分与对比起到了重要作用。     

南海北部第三纪钙质超微化石生物地层学研究

本文根据40口钻井剖面的钙质超微化石分析和研究成果,将南海北部海相第三系,划分出上渐新统至上新统18个超微化石带和始新统1个未命名组合。始新统未命名组合仅见于珠江口盆地东北缘。上渐新统至上新统18个超微化石带为连续沉积,但各带的发育程度不尽相同。其中相当于E.Martini(1971)划分的NN4—NN5带,NN11带和NN13—NN15带发育良好,横向稳定,分布广。它们是南海北部上第三系划分和对比的重要标志。结合部分有孔虫分带和岩性资料,探讨了全区海相第三系的沉积特征及沉积间断分布发育情况。文中还讨论了下、上第三系,第三系与第四系的超微化石划分标志以及再沉积超微化石的特点和地质意义。     

西藏申扎地区的下泥盆统

申扎地区的下泥盆统出露良好、沉积连续、构造单一,生物化石丰富,门类也较为齐全。根据多门类生物化石将下泥盆统进行了划分与对比。在塔尔玛达尔东组为一套以碳酸盐岩为主的沉积地层,中间夹有少量粒级较细的碎屑岩,属于稳定陆棚浅海型沉积。根据岩性和岩相特征可以明显划分为下部和中上部,下部灰岩中产有牙形石、竹节石和头足类,并含有丰富珊瑚和腕足类化石;中上部含有较丰富的珊瑚、腕足类等底栖生物化石,并含有竹节石、牙形石和头足类等游移生物化石。该组的时代为早泥盆世,包括Lochkovian大部以及整个Pragian、Emsian期。     

蒸发岩矿床生物成矿研究综述

现代盐湖生物学的研究和蒸发岩中生物化石的研究都表明，生物在包括芒硝矿床在内的蒸发岩矿床形成中起着重要作用。传统地质学认为蒸发岩是纯化学沉积矿床的观点应予修正。蒸发岩生物成矿研究目前尚处于初级阶段，还需要引入新的研究方法，开展摸拟生物成矿实验，进行更深入的成矿机理方面的研究。     

山西省河东煤田保德地区晚古生代生物成因构造及其环境意义

应用生物成因构造、特征遗迹化石对沉积速率、含氧量、能量级别、底质和含盐度等环境指标的解释，分析了山西省河东煤田保德地区晚古生代沉积环境，认为保德地区晚古生代沉积环境以河流沉积体系、泻湖相浅海相为主，当时沉积底质为半硬到软底，水体含氧量丰富，含盐度比其相邻地区偏低。     

滇东早奥陶世阿莫里坎砂岩相沉积

根据沉积特征、大化石、遗迹化石及微体化石等诸方面证据，认为滇东早奥陶世地层属于广泛分布于西南欧、北非、中东及纽芬兰东部的阿莫里坎砂岩相沉积。     

安徽宿松坐山志留纪晚期地层的研究北大核心CSCD

通过对安徽宿松原称"茅山群"地层的综合研究,发现了2层线形植物化石、植物类表皮微体化石和大型虫管遗迹化石。结合湖南张家界和澧县、重庆秀山、贵州石阡和印江、湖北通山等地志留纪晚期地层的研究结果,确定宿松坐山原称"茅山群"地层的时代为志留纪晚期(Ludlow-Pridoli);依据所含化石和岩性特征,认为这套地层应称为小溪组。综合分析了安徽下扬子地层分区的志留系上部地层,认为该区可能不存在真正茅山群沉积,原称"茅山群"地层为志留纪晚期小溪组。造成该区志留纪兰多维列世特列奇早期之后沉积间断的原因是广西运动的影响。     

比较埋藏学与埋藏相及其环境意义简介及评述

在地层中,各种生物的骨骼具有多种埋藏类型,因而据此可很好地了解骨骼所处位置的沉积环境.Speyer和Brett(1988)用化石保存特征及类型,即骨骼的搬运,解体、破碎及侵蚀,建立了七个晚元古代化石埋藏相.由于本学说诞生不久,所以还有许多必须进一步完善之处:1.埋藏相仅是大陆架沉积边缘环境中化石保存类型的简化模式,而在地质历史中,具有众多的不同沉积环境,不仅有沉积边缘,而且还有陡斜坡跌积边缘.如分布于华南晚古生代的跌积边缘就不适于Speyer等的埋藏相理论.2.怎样建立适用于浊流沉积、风暴沉积及淡水河湖沉积环境的埋藏相.淡水沉积环境与海洋沉积环境十分不同,因而淡水沉积环境的化石保存特征也具有不同于海洋沉积环境的特征.     

Feature

The fossil record contains many examples of the interactions that occurred between organisms. Thus, Cenozoic molluscs are commonly found encrusted by bryozoans, serpulid worms and balanid barnacles; ancient scleractinian corals and echinoderms may show unusual growth patterns as a response to organisms that have embedded themselves into the host's skeleton; fossil bones can preserve indications of biting, gnawing and trampling; and ancient leaves may retain traces of bite marks and leaf miners. Other evidence of interactions may be more cryptic or difficult to interpret, none more so than the evidence of ancient parasitism.     

Fossil–Lagerstätten

Possibly every palaeontologist, before and after Charles Darwin, has been well aware that the fossil record is very incomplete. Only a tiny percentage of the plants and animals alive at any one time in the past get preserved as fossils, both in terms of numbers of individuals and in terms of numbers of species. The palaeontologist attempting to reconstruct ancient ecosystems is therefore, in effect, trying to complete a jigsaw puzzle without the picture on the box lid and for which the majority of pieces are missing. Under normal preservational conditions probably only around 15 per cent of the species composing an ecosystem are preserved. Moreover, the fossil record is biased in favour of those animals and plants with hard, mineralized shells, skeletons or cuticles, and towards those living in marine environments. Thus, the preservational potential of a particular organism depends on two main factors: its constitution (better if it contains hard parts), and its habitat (better if it lives in an environment where sedimentary deposition occurs).     

The First Observation on Plant Cell Fossils in China

For a long time, paleontologists have been focusing on hard parts of organisms during different geological periods while soft parts are rarely reported. Well-preserved plant cells, if found in fossils, are treated only as a rarity. Recent prowess in research on fossil cytoplasm indicates that plant cytoplasm not only has excellent ultrastructures preserved but also may be a quite commonly seen fossil in strata. However, up to now there is no report of plant cell fossils in China yet. Here plant cell fossils are reported from Huolinhe Coal Mine （the early Cretaceous）, Inner Mongolia, China. The presence of plant cytoplasm fossils in two cones on the same specimen not only provides further support for the recently proposed hypothesis on plant cytoplasm fossilization but also marks the first record of plant cytoplasm fossils in China, which suggests a great research potential in this new area.     

河南鲁山寒武系第二统辛集组风暴沉积及其相关的遗迹化石*

河南鲁山寒武系第二统辛集组为一套风暴作用影响下的含磷和海绿石的碎屑岩沉积,主要由中厚层石英砂岩及极薄层泥岩与砂岩互层组成。遗迹化石发育在交错层理砂岩以及极薄层泥岩与薄层砂岩互层的层面上。Skolithos sp. 属于风暴衰减期的Skolithos遗迹相机会种(r-选择)遗迹化石,它们以短小的垂直居住潜穴及低遗迹分异度和丰度为特征。Palaeophycus tubularis,P. striatus,Taenidum sp.,Gordia marina,Planolites montanus,P. beverleyensis等属于风暴间歇期的Cruziana遗迹相均衡种(K-选择)遗迹化石,以水平进食、觅食潜穴为主,遗迹分异度和丰度中等。早寒武世风暴衰减期,频繁的风暴事件不利于研究区机会种遗迹化石的保存,同时风暴间歇期持续时间短、风暴停息期不发育,造成均衡类生物殖居窗口期短暂,亦不利于对沉积底质的连续殖居。这种特殊的风暴沉积以及早寒武世造迹生物较差的掘穴能力,导致研究区遗迹化石种类及数量远不及寒武纪以后的风暴沉积。     

Diminutive trace fossils in the Chengjiang Lagerstätte

Diminutive trace fossils described here have been well preserved in connection with certain pliable carapaces or skeletons of the Chengjiang animals. Taphonomic evidence suggests that these traces were formed in situ. The peculiar preservation indicates that some bilaterians of uncertain affinities seem to have been active at the burial site, constituting an important group of the hidden majority of Cambrian marine community. This may be an essential feature closely associated with the palaeoecology and exceptional preservation of the Cambrian fossil Lagerstätten. The rare preservation of such millimetre‐sized trace fossils raises further doubts about the timing of the initial benthic bilaterians by applying trace fossil evidence.     

Taphonomy of large marine vertebrates in the Upper Cretaceous (Cenomanian-Turonian) Tropic Shale of southern Utah

Sediments from the Upper Cretaceous (Cenomanian-Turonian) Tropic Shale were deposited along the western margin of the Western Interior Seaway, in present-day southern Utah. Marine vertebrates from this formation include plesiosaurs, mosasaurs, bony fish, sharks, and turtles. They are concentrated in the lower portion of the Tropic Shale, mostly between Bentonites B and D. Study of the taphonomic condition of these vertebrates has contributed to an understanding of how they were preserved as well as a detailed paleoenvironment for the Tropic Shale. Physical factors played the dominant role in their preservation, with robust and durable skeletal elements, such as teeth and vertebrae, being most common within the shale. Isolated bones and teeth are also relatively common within the formation, while complete and nearly complete skeletons are more rare. Biological factors played a less dominant role, with no evidence of epifaunal or infaunal activity preserved with any of the skeletal remains. In addition, scavenging marks (both bite and gnaw marks) are relatively uncommon, typically only being found on more complete specimens. A signature of post-burial alteration can be recognized as low levels of abrasion, weathering, and compression and high levels of fracturing of vertebrate skeletal material. Slightly higher levels of abrasion and weathering occur to the west, closer to the ancient shoreline, suggesting some pre-burial alteration. The preservation of marine vertebrates in the Tropic Shale suggests a low energy marine environment with some weak bottom currents and low levels of benthic oxygen. The substrate ranged from soft and soupy to firm, with moderate sedimentation rates resulting in relatively rapid burial.     

贵州福泉牛蹄塘组蠕虫状化石组合的发现

贵州省福泉桅杆坪地区寒武系底部牛蹄塘组黑色页岩中以炭质印模的形式保存有大量宏观后生动物化石.化石微细特征保存较差,多属于疑难化石.该化石组合以化石个体较大的蠕虫状化石和疑似杆壁虫类化石为优势分子,还常见管状类化石、遗迹化石,以及少量的软舌螺、海绵骨针等化石碎片.该化石组合紧位于镍钼多金属层之上,与遵义等地区的松林生物群(牛蹄塘组下生物群)的层位相当,化石组成基本一致,但优势生物存在明显差异.福泉地区牛蹄塘组蠕虫状化石组合的发现,丰富了寒武系牛蹄塘组的生物群面貌,为研究早期后生动物演化提供了新资料和新信息.对该化石组合的进一步研究,也必将为这种特殊生物群的古环境恢复和埋藏学研究提供有利的古生物学证据.      

Preservation of the shell matrix protein dermatopontin in 1500 year old land snail fossils from the Bonin islands

Organic molecules such as proteins can be preserved in certain fossils. The bulk properties of fossil proteins of both vertebrates and invertebrates have been studied for over half a century. Named proteins have so far been identified, however, only in vertebrate fossils, such as collagen from mammoth bones. Using immunological assays, we examined 1500 year old fossils of the extinct land snail Mandarina luhuana from the Bonin islands for the presence of dermatopontin, a molluscan shell matrix protein. First, we examined the shell microstructure and mineralogy of the fossil shells using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) in order to estimate the extent of diagenetic alteration. The results suggest that the original microstructure and mineralogy of the shells are preserved. Antiserum raised against the Type-1 dermatopontin fragment of the living land snail Euhadra brandtii showed significant immunological reactivity with the extracts from the fossil shells of M. luhuana. Immunological binding curves drawn for the shell extracts of extant M. aureola and the extinct M. luhuana confirmed the presence of dermatopontin in the fossil shells and provided an estimate that about 75–98% of the original dermatopontin was lost from the M. luhuana fossils. This is the first report of a named protein being identified in invertebrate fossils.     

中国早白垩世翼龙动物群及其多样性对比

中国西北和东北地区发育中生代河湖相沉积的陆相盆地,其中赋存丰富的脊椎动物化石群,包括天山北部准噶尔盆地的乌尔禾翼龙动物群、天山南部吐哈盆地的哈密翼龙动物群和辽西热河生物群富含翼龙化石。乌尔禾和哈密翼龙动物群都发现于下白垩统吐谷鲁群中,两者的繁盛时间大致相当,这两个动物群的翼龙个体数量巨大,但是物种多样性很低。乌尔禾翼龙动物群的化石多保存在半深湖环境沉积的细砂岩和粉砂岩中,化石保存较为完整,主要为正常死亡;哈密翼龙动物群的化石富集保存在滨浅湖环境事件沉积的风暴岩中,大都经过了大型风暴的短距离搬运和快速埋藏,骨架分散,但几乎所有单个骨骼完整。东北地区的热河生物群翼龙种类众多,共生包括鱼类、两栖类、恐龙等其他爬行类、鸟类和哺乳类等脊椎动物,生物多样性极为丰富,大多保存在半深湖-深湖环境形成的页岩中,骨架多为完整保存,是火山爆发事件导致其集群死亡,并被火山灰快速埋藏,与新疆的动物群面貌明显不同。根据天山南北的翼龙动物群初步对比,乌尔禾翼龙动物群的主要优势类群准噶尔翼龙类,在天山北部的准噶尔盆地及相邻的蒙古西部地区都有分布,与天山南部的哈密翼龙动物群中已知唯一翼龙类群哈密翼龙完全不同,两者亲缘关系很远。因此认为在中生代,天山的隆升就已经达到了一定的高度,并对翼龙的南北迁徙交流形成了有效的地理阻隔。依据中国东北和西北地区早白垩世翼龙动物群对比,认为辽西及相邻周边地区由于华北克拉通破坏,导致大量火山活动,造成了生态环境的多样性和生物种类的快速更替,从而形成了热河生物群独有的极高的生物多样性,而缺少火山活动、环境相对单一的西北陆相盆地,虽然翼龙类具有数以千万计的庞大居群,但是物种多样性很低。华北克拉通破坏导致的辽西地区频繁而强烈的火山活动,是形成中国西北和东北早白垩世生物多样性差异的重要原因。