四川盆地须家河组地层划分方案讨论

从晚三叠世盆地演化阶段划分和物源方向分析出发,认为晚三叠世处于巴颜喀拉海控大陆边缘盆地向受控于龙门山推覆抬升的川西前陆盆地的转化时期,其间重要的盆地转换界面就是须三、须四段之间的安县运动界面。在对南北向和东西向钻井、露头剖面的区域地层进行详细划分对比基础上,认为须下盆的须二、须三段地层主要发育在川西地区中北段,并以鸭子河地区最为发育,往南因受安县运动影响,须三段地层遭受剥蚀,从北往南逐渐减薄缺失,在大邑构造减薄,在平落坝缺失须三段,造成须二段与须四段不整合接触。从川西地区往东须二段、须三段也逐渐变薄,在川中地区缺失。川中、川南和川东地区的须家河组与川西地区须上盆即须四段、须五段地层相当。     

四川广元志留系Ludlow统的再研究兼论车家坝组的含义

四川广元地区志留纪晚期地层曾被划分为金台观组、车家坝组和中间梁组,后被厘定合并为一个组,即车家坝组。通过对岩性组合特征和生物化石群面貌的分析,广元地区晚志留世地层在岩性、生物化石生物群面貌方面具有一致性,赞成将三组归入同一个岩石地层单元——车家坝组,代表近岸、正常浅海(平均浪基面以上)沉积(BA2—BA3)。对比分析表明,该组的牙形刺Ozarkodina crispa应鉴定为Ozarkodina snajdri。这是O.snajdri牙形刺带在中国的首次报道。依据牙形刺化石,车家坝组的时代被修订为中Ludlow世晚期—晚Ludlow世早期。该组上部发现几丁石Sphaerochitina sp.组合,可与O.snajdri牙形刺带和bohemicus tenus-kozlowskii笔石带进行对比。     

Biogenic Sediments and Their Paleoceanographic Implication in West Pacific Warm Pool during the Pleistocene

Primary productivity has played an important role in the global carbon cycle during the Quaternary. The average Corg/N ratio was 7.0 from the core MD97-2140 in the West Pacific Warm Pool (WPWP) over the last 1 755 ka, which indicates a main contribution of marine organic carbon to the organic matter in the sediments. Large fluctuations in mass accumulation rates (MARs) of biogenics and lithogenics from this core since the marine isotope stage (MIS) 6 reflected the moderate variability in oceanographic condi...     

Characteristics and Environmental Significance of pH and EC in Summer Rainfall and Shallow Firn Profile at Yulong Snow Mountain,Lijiang City,China

The seasonal and inter-annual variations of pH and EC(electrical conductivity) at Yu-long(玉龙) Snow Mountain,Lijiang(丽江) City,are sensitive to precipitation variations and are important indicators of the atmospheric environment.The pH of summer rainfall at Lijiang City ranges from 6.7 to 7.4,and alkaline mineral salts dominate the variations of rainfall acidity.pH values in theshallow firn profile at Baishui(白水) Glacier No.1 range from 5.6 to 6.3,and EC values from 2.4 to 7.3 μs/cm.The ranges are lower than ...     

Observed Glaciohydrological Changes in China's Typical Monsoonal Temperate Glacier Region since 1980s

Under the background of significant climate warming since the 1980s,the glaciers in China's monsoonal temperate glacier region respond to the warming intensely.Based on the glaciohy-drological observations at some typical glaciers from Mts.Yulong(玉龙) and Gongga(贡嘎) of Heng-duan(横断) Mountains Range in the southeastern Tibetan plateau,the glaciohydrological changes in the temperate glacier region since the 1980s were investigated.First,the glacier terminus exhibited an accelerating retreat.Second,as the glaci...     

Middle Jurassic Coptoclavidae (Insecta:Coleoptera:Dytiscoidea) from China:a Good Example of Mosaic Evolution

<正>Adults of the aquatic coptoclavid beetles(Coleoptera:Adephaga:Dytiscoidea),described from four Middle Jurassic fossil localities in Inner Mongolia and Liaoning in northeastern China,are attributed to Daohugounectes primitives Wang,Ponomarenko and Zhang,2009,which was previously proposed after study of larvae.The generic name Timarchopsis Brauer,Redtenbacher and Ganglbauer,1889 is proposed as a substitute for the preoccupied and junior homonym Necronectes Ponomarenko,1977,non Milne-Edwards,1881. Furthermore,the subfamily name Necronectinae Ponomarenko,1977 is substituted by the available name Timarchopsinae.Daohugounectes is placed into Timarchopsinae because its adults have long,slightly apically widened tibiae and small femoral plates.The adults of this genus differ from those of other Timarchopsinae in the following features:antennae short and widened in the middle part;basal segments of protarsi not cut apically; metaventrite with a triangular plate.The larvae look like somewhat primitive forms in the subfamily Timarchopsinae.In contrast to these primitive larvae,the adults with some advanced characters can be regarded as among the most advanced forms in the subfamily Timarchopsinae,and probably represent a transition between the Timarchopsinae and Charanoscaphinae.Such mosaic evolution within Daohugounectes indicates that the evolutionary process of aquatic beetles is far more complex than previously thought.     

Latitude-Dependent Response of East Asian Summer Monsoon to External Forcing in the Last Millennium

Response of the East Asian summer monsoon(EASM) rainfall to external forcing(insolation,volcanic aerosol,and greenhouse gases) is investigated by analysis of a millennium simulation with the coupled climate model ECHO-G.The model reproduces reasonably realistic present-day EASM climatology.The simulated precipitation variation in East Asia over the last millennium compares favorably with the observed and proxy data.It is found that the features and sensitivity of the forced response depend on latitude.On...     

Erratum to: Estimation of the 2001 Kunlun earth-quake fault slip from GPS coseismic data using Hori’s inverse method

An error was introduced in title of section 3 of our paper. The correct title is "Estimation of slip distribu-tion". The online version of the original article can be found at http://dx.doi.org/10.1007/s11589-009-0609-x.     

柴达木盆地北缘早古生代高压——超高压变质带中发现典型超高压矿物——柯石英

从都兰北带榴辉岩的片麻岩围岩的锆石中发现了柯石英包裹体和石墨包裹体，说明该超高压带的峰期变质作用已达柯石英稳定区间（＞2.8GPa）但小于金刚石的稳定区间（＜3.5GPa），从而确定柴达木盆地北缘存在早古生代超高压变质作用和陆－陆碰撞作用，为中国中部存在一条横贯东西的早古生代（大致500－400Ma）高压超高压变质带的推断提供了新的关键性证据。