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.     

New Isophlebioid Dragonflies from the Middle Jurassic of Inner Mongolia,China(Insecta:Odonata:Isophlebioptera:Campterophiebiidae)

Three new species of fossil dragonflies assigned to Sinokaratawia Nel,Huang and Lin in family Campterophlebildae,i.e.S,daohugouica sp.nov.,S.magica sp.nov.and S.gloriosa sp.nov.,and new materials of male S.prokopi Nel,Huang and Lin,2007 are described from the Middle Jurassic of Daohugou,Inner Mongolia,China.An emended diagnosis of genus Sinokaratawia was proposed.     

大岭子金矿地质特征及选矿浸出率

大岭子金矿V1矿体赋存于中元古界高黎贡山群变质岩中,受韧性剪切带控制,矿石类型以氧化矿石为主。提出选矿依据。     

藏西北三岔口地区泥瓮系生物礁特征及其意义

在羌塘西部的三岔口一带泥盆系拉竹龙组中发现规模较大的生物礁——台地前缘礁。下层礁体厚7．28m，上层礁体厚40.98m。两个礁体均为叠置礁，礁体由礁基、礁核、礁顶组成。剖面显示发育有礁前垮塌角砾、礁格架、礁间及礁后环境。泥盆纪生物礁的发现为羌塘盆地寻找油气资源提供了新思路。     

New specimens of a fossil ostrich from the Miocene of Kenya

Fossilised hind limb bones from the late Middle Miocene (approximately 14 million-year-old [MYA]) Fort Ternan, Kadianga West and Ngorora localities in Western Kenya indicate the presence of a new representative of the ostrich genus Struthio. These new fossils represent some of the oldest known records for Struthio yet described, slightly younger than Struthio coppensi, from the Lower Miocene of Namibia. Because the four sub-species of the modern-day ostrich (Struthio camelus camelus, Struthio camelus australis, Struthio camelus massaicus, and Struthio camelus molybdophanes) inhabit the plains of Africa, and as recently as the 1940s, a fifth sub-species was also present in the Middle East and Saudi Arabia (Struthio camelus syriacus), records of Struthio from Kenya and Namibia testify to the much wider distribution of these cursorial birds in the relatively recent past. This is further supported by the very high frequency of ostrich eggshell fragments found across Africa and Eurasia, which vastly outweighs the amount of skeletal material uncovered over the last century.     

A pronounced dry event recorded around 4.2 ka in brine sediments from the northern Red Sea

Partly laminated sediments were sampled from the brine-filled, anoxic Shaban Deep basin in the northern Red Sea. At about 4200 cal yr BP more than two millennia of anoxic sedimentation is replaced by a sub-oxic facies strongly suggesting the episodic absence of the brine. At the same time stable oxygen isotopes from surface dwelling foraminifera show a sharp increase (within less than 100 yr) pointing to a strong positive salinity anomaly at the sea surface. This major evaporation event significantly enhanced the renewal of deep water and the subsequent ventilation of the small Shaban Deep basin. The timing and strength of the reconstructed environmental changes around 4200 cal yr BP suggest that this event is the regional expression of a major drought event, which is widely observed in the neighboring regions, and which strongly affected Middle East agricultural civilizations.     

Sequence stratigraphy of a Late Devonian ramp-situated reef system in the Western Canada Sedimentary Basin: dynamic responses to sea-level change and regressive reef development

The Alexandra Formation, located in the Northwest Territories of Canada, is formed of a Late Devonian (Frasnian) reef system that developed on a gently sloping, epicontinental ramp in the Western Canada Sedimentary Basin. High‐resolution sequence stratigraphic analysis of its deposits delineates two reef complexes that are separated by a Type I sequence boundary. The second reef complex developed on the outer ramp, basinward of the first, after sea‐level fell ≈17 m. Stratigraphic complexity of the second reef complex was a result of its initiation during forced regression, and its development through an entire cycle of sea‐level rise followed by sea‐level fall. Its highstand systems tract was not characterized by high rates of carbonate production or sediment shedding. Rather, these features took place as sea‐level fell, after its highstand systems tract. The sequence stratigraphic framework of this regressive reef system highlights a number of depositional parameters that differ from high‐relief, shelf‐situated reef systems with steep, narrow margins. These have implications for understanding the controls on the development of ramp‐situated reef systems, and the nature of reef systems with gently sloping profiles. This study demonstrates that the development of stromatoporoid reef systems may be far more complex than generally realized, and that high‐resolution sequence stratigraphy may provide the tools for better understanding of complex, often enigmatic, aspects of these systems.     

Présence d'une mangrove à Avicennia au Miocène moyen dans la région de Digne (Alpes-de-Haute-Provence,France) : implications stratigraphiques et paléoclimatiques

Avicennia pollen grains have been discovered in marine facies from the Middle Miocene deltaic series of Châteauredon (southeastern France). Based on the local stratigraphy, an age between 15.8 and 16.5 Ma is proposed for these grains. The age and the transgressive context of the Avicennia bearing-levels are in agreement with the maximum extension of the mangrove known in the western Mediterranean during interval N8–NN4 pro parte, in relation with the Langhian highstand. This mangrove occurrence at 42°N latitude during Middle Miocene is a more northern witness of the mangrove sites known in Languedoc and Provence areas. It also implies a lower climatic gradient than today. To cite this article: J.-J. Châteauneuf et al., C. R. Geoscience 338 (2006).