四川武隆地区二叠—三叠系磁性地层学研究

四川武隆地区的p/T界线为一化石丰富、沉积连续的海相碳酸盐剖面。通过对岩石磁学的研究,鉴别出三叠系灰岩样品以磁铁矿为主,其中约70％为多畴磁铁矿。ChRM由单畴磁铁矿所携带。二叠系灰岩样品主要为单畴与超顺磁颗粒的磁铁矿,样品不同程度地遭受重磁化。然而,根据其退磁中NRM矢量变化的轨迹与极性有关,使确定绝大部分样品的极性成为可能。本文通过与国外剖面的对比,认为Illawarra反转起始于吴家坪阶上部,而Kiaman极性段中则存在着若干正向极性。     

希土与三甘醇—二(2, 2''—乙酰丙酮—4, 4''—甲基)苯基醚配合物的研究

以合成的一种新化合物三甘醇－二（２，２＇－乙酰丙酮－４，４＇－甲基）苯基醚作配体，在无水甲醇中合成了七种希土氯化物的配合物，确定其组成是ＬｎＬＣｌ（Ｌｎ：Ｌａ，Ｃｅ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ和Ｄｙ），Ｌ：三甘醇－二（２，２＇－乙酰丙酮－４，４＇－甲基）苯基醚。由ＩＲ，ＵＶ，ＴＧ－ＤＴＧ和display status     

GEOCHEMISTRY OF IGNEOUS ROCK IN PANXI RIFT

In this paper the petrogenesis and magmatism of igneous rocks in the Panxi Rift are discussed based on the major element, transition metallic element, REE and other trace element analysis data of more than 40 samples.According to major element data, a feature of bimodal distribution is displayed. The transition metal patterns show that Cr and Ni are highly depleted and Ti is highly concentrated, reflecting a rather complex history of crystallization differentiation.The distribution patterns of hygromagmatophile element abundance of basalts normalized with primary mantle values are shown to be intermediate between those of alkali basalts and continental tholeiites. This provides evidence suggesting that the basalts were generated in a rift tectonic environment, and that the primary magma came deeply from the primary mantle as a result of partial melting of garnet lherzolite.     

HUANAN ALPS, NOT SOUTH CHINA PLATFORM

The notion that South China was a post-Caledonian platform is clearly proven incorrect by the ev-idence of Mesozoic deformation and igneous activities. Reinterpretation of map patterns suggested the pres-ence of Mesozoic orogenic belt comparable to Southern Appalachians in dimension and in style of de-formation. Field work in 1985 led to the discovery of possible flysch and rigid basement nappes, whichhave been thrust onto carbonate platform. A suture zone has been identified. The Huanan Alps owed itsorigin to Indosinian Orogeny, which eliminated a Paleo Tethyan Seaway, the Xiangganzhe (Hunan-Ji-angxi-Zhejiang) Ocean between the Yangtze and Huanan Terranes.     

华北断块西南部晚太古代成铁盆地构造演化的初步研究

我国前震旦纪的鞍山式铁矿,应该根据时代和含铁建造类型作进一步划分。它可以分为早太古代的太平寨型、既太古代弓长岭型和早元古代樱桃园型三个亚类。本文对桂村和八台地区晚太古代弓长岭型铁矿的绿岩系含铁建造进行了研究。这套岩系均经受了角闪岩相变质作用。通过原岩恢复和镁绿岩的研究,说明该地区处于岛弧-海沟间隙的大地构造位置。橄榄岩质镁绿岩的分布表明有一条南北向消亡了的扩张脊。用岩石化学数据和质谱计分析的铷、锶数据推算了地壳厚度和古贝尼奥夫带深度,进一步肯定了弧沟间隙盆地的构造特征。同时恢复了古成铁盆地的几何形态。文中还概要地分析了华北断块前震旦纪时期的地质演化历史,进而将桂村和八台地区的晚太古代成铁盆地的构造演化历史分为四个阶段:盆地形成前的东西拉张阶段、消减作用阶段、弧沟间隙盆地沉积阶段和盆地沉积期后阶段。赵案庄型铁矿属第一阶段,二铁型铁矿是第三阶段产物。     

是华南造山带而不是华南地台

华南是一个加里东期后地台的观念,已为中生代变形作用和火成活动的证据证明显然是错误的。地质图图型的重新解释指出了存在一个规模和交形样式均可与阿巴拉契亚南部相类比的中生代造山带。1985年的野外工作使我们发现了已经冲断到碳酸盐台地之上的可能的复理石和刚性基底。已经鉴定出一条缝合带。华南造山带是印支造山运动生成的,这次造山运动导致了杨子地体和华南地体之间的湘赣浙洋盆这个古特提斯海路的消失。     

攀西裂谷火成岩组合的微量元素地球化学

本文依据攀枝花-西昌裂谷四十几个火成岩的主要元素、过渡金属元素、稀土元素和其他微量元素的分析结果,探讨了这些岩石的成因和岩浆过程。从主要元素成分来看,明显地显示出双众数岩套的特征。过渡金属元素显示了Cr和Ni的强烈亏损与Ti的明显富集,反映了复杂的结晶分离作用历史。所有岩石的稀土元素分配型式都是富集型的,暗示出原始岩浆可能来自原始地幔的低程度部分熔融,玄武岩的亲石岩浆元素丰度经原始地幔值标准化后的分配型式,显示出一种介于碱性玄武岩与大陆拉斑玄武岩之间的图形,这支持了它们的裂谷大地构造环境,也暗示了原始岩浆来自深处的原始地幔区,可能是石榴二辉橄榄岩部分熔融的产物。     

东南极拉斯曼丘陵及其邻区的泛非热事件

本文以Sm-Nd内部等时年龄,单颗粒锆石~(207)Pb-~(206)Pb逐层蒸发年龄和黑云母~(40)Ar/~(39)Ar坪年龄为根据,论述了东南极拉斯曼丘陵泛非热事件。野外地质和同位素年代学的证据表明,该热事件不仅有区域强烈的部分熔融,而且还有低压麻粒岩相变质。它的产生可能与冈瓦纳古陆的最终形成有关。     

Permo-Triassic Magnetostratigraphy in Wulong Area, Sichuan, China

The Permo-Triassic boundary in Wulong area, Sichuan Province, South China lies in a continuous marine carbonate succession with abundant fossil records. Two well-exposed sections were sampled for magnetostratigraphic studies. The experimental results of rock magnetism reveal that the samples from the Triassic limestones contain only magnetites among which 70% are multi-domain. The ChRM direction is carried by remaining 30% of single-domain magnetite. The Permian limestone samples are dominated by single-domain to superparamagnetic magnetites with little ChRM direction due to their fine-grained texture. Nevertheless, the polarity determination is still possible based on the NRM vector changes during thermal demagnetization. A Permo-Triassic polarity profile in Wulong area is established in the paper, and a tentative correlation with other known profiles is pursued. The authors suggest that the Illawarra reversal starts at the upper part of Wujiapingian, while some normal polarity events may exist in the     

二滩坝址F-20断层泥中方解石的热发光年龄测定

本文研究了二滩坝址玄武岩中方解石的热发光性质。这些方解石是中温热液蚀变的产物,当受到新断裂活动作用时,方解石晶体发生变形。实验表明,方解石受压力作用时,其天然热发光逐渐衰减,直至全部消失。根据这种原理,可以用二滩坝址方解石变形后积累的天然热发光测定最新断层活动的年龄。利用这种方法测得方解石受压变形事件发生在距今140.3万年和115.5万年之间。据此推断F-20老断层复活时期不晚于距今115.5万年。