苏子河盆地中生代生物地层研究

本文报道了辽东苏子河盆地中生代各门类化石,其中植物、双壳、腹足各3属3种;叶肢介6属12种(包括3个新种);介形虫7属10种;昆虫2属2种(包括一新属新种);硅化木1属1种,还有鱼类等,新命1新属4个新种。据此将苏子河盆地的小东沟组、小岭组、梨树沟组、聂尔库组和打石沟组的时代归属为早白垩世,并将小东沟组和小岭组与辽西的义县组及安徽的毛坦厂组进行对比;梨树沟组和聂尔库组与辽西的阜新组及安徽大别山区的黑石渡组进行对比。     

First report of trace fossils from Palaeogene succession (Namunagarh grit) of Andaman and Nicobar islands

The Namunagarh grit of Eocene age in South Andaman island is a submarine fan deposit where sedimentation occurred in deep marine environment mainly by turbidity currents. The mudstone and fine-grained sandstone of the turbidite sequence yielded three ichnogenera viz Thalassinoides, Teichichnus and Lorenzinia. Typically shallow marine Thalassinoides burrows co-occur with deep water burrows represented by Teichichnus and Lorenzinia, indicating a dominant control of substrate, availability of food and rate of sedimentation against bathymetry on distribution of trace fossils. Trace fossils are particularly abundant in the mudstones pointing to a strong lithofacies control. A well-oxygenated muddy bottom with a low rate of sedimentation is envisaged. An order in the succession of traces could be deciphered. Simply constructed burrows of Thalassinoides appeared initially followed by complex structures of Teichichnus and ornate Lorenzinia.     

Interest in geological and palaeontological curiosities by southern African non-western societies: A review and perspectives for future study

Compared with other parts of the world, the study of geomythology in southern Africa, and the associated documentation of non-western awareness of palaeontological and geological phenomena, is in an early phase. We focus on examples of rocks and fossils as items of special interest and curiosity, and we search for evidence of an indigenous palaeontology and geology. We review twenty-one sites or cases for which published accounts exist, and we describe a newly identified trilobite manuport site. In combination these sites provide various levels of evidence of palaeontological and geological awareness exhibited by non-western cultures in southern Africa, and how these cultures incorporated this knowledge into their understanding of their world. We anticipate that in time a diverse heritage of such ‘natural knowledge’ may become evident in southern Africa, aided in part by recognition of the possibility that rock art images may be associated with awareness of body fossils and trace fossils. We suggest ways in which further analysis may bolster this contention.     

西藏羌塘盆地光明湖地区早白垩世化石的发现及意义

西藏羌塘盆地以发育中生代海相地层为特征,成为近年来油气勘探的重要区块。对于整个盆地的中生代海相沉积是否跨入早白垩世过去仍存在一些争议。本次在光明湖一带的白龙冰河组上部采集到大量早白垩世化石,证实了该组沉积晚期已跨入早白垩世,为区域上与该组同时异相的其它中生代地层沉积时代的进一步厘定提供了新的化石依据。对整个羌塘盆地晚侏罗世—早白垩世沉积古地理的研究,以及羌塘盆地早白垩世海相地层的圈定和油气地质条件的探讨具有重要意义。     

Further evidence supporting high diversity of cyathealean tree ferns in the Early Cretaceous of Antarctica

Two new specimens of a cyathealean fern stems collected from the Lower Cretaceous (Aptian) Cerro Negro Formation, which crops out at the South Shetland Islands, Antarctica, are described in detail. The specimens are dictyostelic stems with U-shaped meristeles without sclerenchyma sheaths and petiole bases with numerous, small, vascular strands, and a mantle of adventitious roots. The anatomy of the stems show similarities with Cibotiaceae, but given they are not well preserved, some critical features that would allow a conclusive referral to this family are lacking. Preserved in the surrounding matrix, fragmentary pinnules were found, showing sori with bivalvate indusia, and sporangia with more than 20 spores, attached to an elongate receptacle. The features observed in these fertile remains suggest cyathealean affinities, but are difficult to refer to a particular family. These findings increase the diversity of cyathealean tree ferns in the Cerro Negro Formation, supporting previously suggested warm climatic conditions for this region of Antarctica during the Aptian.     

Polar aromatic biomarkers of Miocene-aged Chukurovo resinite and correlation with a progenitor macrofossil

Functionalised aromatic constituents of Chukurovo resinite are compared here with the chemical composition of a macrofossil assigned paleobotanically as Taxodium dubium (Sternb.) Heer. Terpenoids and lipids of fossil wood tissue embedded in a clay sediment were extracted and analyzed for comparison. The information was interpreted in relation to the biomarker compositions of different conifer families, as well as to the effects of contamination by inward migration of organic matter from the adjacent sediments.Many of identified geolipids, i.e., alkanes, alkanols, alkan-2-ones, and steranes/triterpanes have no chemosystematic value because they are ubiquitous in the plant kingdom. Ferruginol, sugiol, and products of their diagenetic transformations were identified as the dominant specific biomarkers in the resinite. Ferruginol and its analogues were the most abundant diterpenoids in Taxodium dubium sample. Thus, the biomarker composition of the extractable matter of the resinite strongly suggests that species of Cupressaceae contributed significantly to the Chukurovo paleoenvironment.     

中国发现的完整麇鹿(Elaphurus davidianus Milne—Edwards,1866)角枝化石和它们的科学意义

鉴于野生麋鹿在人们直接研究它的野生习性前已经绝灭,简接推断总带有某些危险性,而本文报导的一件产于青浦的、连同先前发表过的10余件产于我国其它地区的比较完整的角枝,区别于遗址中的多数破碎标本,先民干扰的因素较少,它们和它们产出的地层却有希望弥补不足,能直接反映当时的古生态和自然面貌,因而具有特别重要的科学意义。     

Depositional history of a muddy sabkha complex in the Sokoto Basin of Nigeria,West Africa

Sedimentological and stratigraphical analysis of the Sokoto Basin has resulted in recognition of four lithostratigraphic units. They are Unit A—siltstone and fine-grained sandstone; Unit B—shale and marl; Unit C—limestone and calcareous shale; and Unit D—red sandstone. Unit A represents a wadi plain system composed of desert-alluvial beds; Unit B, a mud-rich sabkha system; and Unit C, an inner-shelf carbonate system. A marine transgression from the northwest began in the Maastrichtian and reached its peak in the Palaeocene. After regression in the late Palaeocene, the area was subjected to erosion, followed by fluvial sedimentation of Unit D. Wadi plain beds and mud-rich sabkha facies of Sokoto Basin are similar to alluvial and coastal mud-flat deposits in the northwestern Gulf of California and ephemeral stream and tidal-flat sediments in Gladstone Embayment, Australia.     

The hunt for Precambrian fossils: An abbreviated genealogy of the science

In 1859, in his great work On the Origin of Species, Darwin repeatedly raised what he regarded to be the most serious problem facing his theory of evolution – the lack of fossils predating the rise of shelly invertebrates that marks the beginning of the Cambrian Period of geological time (550 Ma), an “inexplicable” absence that could be “truly urged as a valid argument” against his all-embracing synthesis. This missing early fossil record posed a major dilemma, for Darwin's theory demanded firm linkage from the less advanced to the more evolved, from primitive microbes to protozoans to the rich faunas of the basal Phanerozoic for which no fossil evidence was known. For more than 100 years, the history of Precambrian life stood out as one of the greatest unsolved problems in natural science. In recent decades, however, understanding of life's early evolution has changed markedly as the documented fossil record has been extended seven-fold to some 3500 Ma, an age more than three-quarters that of the planet. This long-sought solution to Darwin's dilemma was set in motion by a small vanguard of workers who blazed the trail in the 1950s and 1960s, just as their course was charted by a few prescient pioneers of the previous century. All workers today, including the 28 participants in the recently held World Summit on Ancient Microscopic Fossils, have roots that can be traced to the pathfinders of a half-century ago.