中元古代长城纪遗迹化石在宁夏贺兰山的发现

简要报道了宁夏贺兰山中元古界长城系黄旗口组中发现的遗迹化石,并与有关非生物沉积构造进行了对比讨论。这些遗迹化石的发现,为研究后生动物起源及其演化提供了新的佐证。     

西藏侏罗纪双壳类化石组合特征

该文详细论述了西藏侏罗纪双壳类化石组合特征、地理分布和共生生物的关系,并划分为喜马拉雅和冈底斯-念青唐古拉-三江两生物地理区。     

显微拉曼光谱对恐龙化石内部成分研究

文章对云南省三个不同时期的恐龙化石内部成分进行了研究。拉曼光谱结果表明,三个不同时期恐龙化石内部的主要成分是CaCO3晶体,在早、中侏罗纪化石内部发现有SiO2晶体,而晚侏罗纪化石内部则没有。它表明晚侏罗纪化石的硅化环境条件与早、中侏罗纪化石的硅化环境条件相差较大。实验所获资料可为恐龙化石源地及年代鉴别提供一定的依据。     

Robust Chemical Preservation of Digital Information on DNA in Silica with Error‐Correcting Codes

Information, such as text printed on paper or images projected onto microfilm, can survive for over 500 years. However, the storage of digital information for time frames exceeding 50 years is challenging. Here we show that digital information can be stored on DNA and recovered without errors for considerably longer time frames. To allow for the perfect recovery of the information, we encapsulate the DNA in an inorganic matrix, and employ error‐correcting codes to correct storage‐related errors. Specifically, we translated 83 kB of information to 4991 DNA segments, each 158 nucleotides long, which were encapsulated in silica. Accelerated aging experiments were performed to measure DNA decay kinetics, which show that data can be archived on DNA for millennia under a wide range of conditions. The original information could be recovered error free, even after treating the DNA in silica at 70 °C for one week. This is thermally equivalent to storing information on DNA in central Europe for 2000 years.     

Molecular fossils and oil-source rock correlations in Tarim Basin, NW China

The distribution of "molecular fossils" (bio-markers) of steroid compounds in extracts from some spe-cific geologic age in the Tarim Basin have been analyzed andare used as the fingerprints for the oil-source rock correla-tion. Having been affected by maturation, migration, phasefractionation and biodegradation, not any molecular fossilsrelated to source and environment can be used as the finger-prints for oil-source rock correlation. Some special bio-markers widely existed in the extracts from Cambrian andOrdovician rocks in the Tarim Basin and showed obviousdifference in each stratum, including dinosteranes (C₃₀),4-methyl-24-ethyl-cholestanes (C₃₀) and their aromatizedsteroids, C₂₄-norcholestanes and C₂₈ steranes originated fromdinoflagellates and diatom. Few oils such as the heavy oildrilled in the Cambrian reservoir from Tadong 2 well (TD2)correlated well with the extracts from the Cambrian. Theamazing similarity of the relative contents of these com-pounds between the marine oils produced in Tazhong andTabei uplifts and the extracts from the Upper Ordoviciansuggests that the Middle-Upper Ordovician is the very likelymain source for the marine oils.     

Phosphatized biotas from the Neoproterozoic Doushantuo Formation on the Yangtze Platform

The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts, carbonaceous shales, and phosphorites, onto the late Neoproterozoic biosphere. The phosphatic window is unusually clear; Doushantuo phosphorites at Weng'an (Guizhou Province) are known to exquisitely preserve a multitude of single-celled eukaryotes, multicellular algae, and microscopic animals. Our recent survey reveals that, in addition to the now famous Weng'an locality, Doushantuo phosphorites at Baokang (Hubei), Chadian (Shaanxi), and Shangrao (Jiangxi) also contain diverse eukaryotes preserved at the cellular level. All these phosphorites were deposited in shallow-water environments, typically above fair weather wave base and close to ancient islands. Along with Doushantuo cherts and shales, these phosphorites give us a clearer and more complete picture of late Neoproterozoic biological evolution: there is a remarkable diversification of multicellular eukaryotes shortly after several Neoproterozoic glaciation events.     

北祁连东段天祝冷龙岭一带三叠纪地层

近年来的调查研究表明，分布于北祁连东段天祝冷龙岭一带的叠系可划分为上三叠统和中三叠统两部分。前者含较丰富的我国北方晚三叠世Ｄ－Ｂ植物群化石，与甘肃靖远晚三叠世南营儿群最接近，同属温湿气候条件下的河流相至湖泊沼泽相含煤碎屑沉积。后者化石少，但能显示出较老的中三叠世面貌，与白银丁家窑组一致，建议用南营儿群和丁家窑组分别代表本区的晚三叠世和中三叠世地层。