吉林南部杉松岗植物群及其地质时代

吉林南部杉松岗盆地早侏罗世植物群主要由松柏类、银杏类、真蕨类和茨康类组成，迄今已发现22属37种。其典型特征是锥叶蕨(Coniopteris)与准苏铁果(Cycadocarpidium)共生，显示了欧亚大陆早侏罗世植物群早期组合的特征，其地质时代似为早侏罗世早期。这一发现对确定杉松岗盆地含煤地层的地质时代和建立我国北方侏罗纪植物群序列具有重要的科学价值，对探讨吉林南部的地质发展史也具有重要的意义。     

Late Ordovician and Early Devonian conodonts from Onoo Tolgoi area of Mongolia

Conodont samples were collected from three localities in the Onoo Tolgoi area, Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation （M288-M294） lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation （M295-M299） contain Ozarkodina pandora alpha Morph. （ P element）, clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities （M300-M303） yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf. baotaensis, Eoplacognathus fianyeen- sis, Eoplacognathus protoramosus ; Baltoniodus alobatus ; and ？ Ambalodus triangularis ; the age is Late Ordovician, more precisely, early-middle Late Ordovician.     

黑龙江嘉荫地区古近纪早期古气候分析

黑龙江嘉荫地区是在我国范围内最有希望找到确切陆相白垩系一古近系界线的地区之一,定量研究界线附近古气候变迁有助于了解该界线前后的生物灭绝与复苏过程。本文以乌云组含煤段第10层所产20属29种木本双子叶被子植物化石为根据,定量研究了嘉荫地区白垩系古近系界线之后的生物复苏的环境条件。“叶相一气候多变量程序”定量分析结果显示,该区古近纪早期年均温度(MAT)约11．45℃,属暖温带气候类型;“叶缘分析”得出年均降水量(MAP)约为1424mm,林相总体上属混交中生林。     

Proposed GSSP for the base of Cambrian Stage 9, coinciding with the first appearance of Agnostotes orientalis, at Duibian, Zhejiang, China

Exposed in natural outcrops near the Duibian Village, Jiangshan County, Zhejiang Province, China, the Duibian B section is proposed as the boundary stratotype for the base of an unnamed stage termed provisionally Cambrian Stage 9. The proposed position of the GSSP is 108.12 m above the base of the Huayansi Formation, at a horizon coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalis. This horizon coincides also with the first appearance of the cosmopoli-tan polym...     

New material of Cordaites baodeensis Sun from Lower Permian Shanxi Formation of Baode,Shanxi

Based on the anatomical study of leaf cuticles of Cordaites from the Lower Permian Shanxi Formation in Baode of Shanxi,the author analysed the epidermal characters of Cordaites in this area.On the base of the abundant compressions and laboratory studies,the author complemented some new data of the cuticular characters of the species Cordaites baodeensis Sun for its study of taxonomy.Meanwhile,the author newly discovered a number of sporopollen fossils associated with the mega-plants of Cordaitales,described...     

The developmental trend of labrum and median eyes of Orsten-type preserved Phosphatocopina (Crustacea)

The Phosphatocopina (Crustacea,Arthropoda) is an important group of 'Orsten-type' preserved fossils.It is resolved as the sister-group of Eucrustacea.Here we study the labrum,the median eyes,and the inner lamella of Phosphatocopina based on the selected specimens respectively from western Hunan,South China,and Sweden.The labrum characters of different species exhibit interspecific difference.The ratio of labrum length/shield length is significant to the reconstruction of the ontogeny of phosphatocopines.The...     

“清河镇群”年代地层学研究进展

本文根据"清河镇群"(或"开原岩群")年代地层学研究新进展,即在上肥地剖面原划入北大沟组、吴家堡子组,尖山子水库大坝原划入北大沟组等地层中获得的岩浆结晶锆石(SHRIMP)年龄2497±27 Ma、2522±17 Ma,250±5 Ma;在"白砬子组"(或"照北山岩组")之建组剖面东杨木林子的大理岩(结晶灰岩)中获得震旦纪之微古植物化石--Stictosphaeridium tortutosum,Synsphaeridium sp.,Hystrisphaeridium sp.等,结合前人研究成果和区域地质构造特征,提出清河断裂为华北板块(清原地块)与北部陆缘活动带(兴蒙或吉黑造山带)的界线,前人划分的"辽河群"或"清河镇群"或"开原岩群"是分布在不同大地构造单元内的、不同属性的地质体的拼合物.并重新划分为清河断裂带之南华北板块内的新太古代英云闪长岩和古元古代芦家堡子岩组;清河断裂带以北华北板块北部陆缘活动带的构造岩石地层-新元古代(震旦纪)西保安岩组、早寒武世佟家屯岩组和晚二叠世尖山子火山岩.