塔中地区志留系碎屑锆石测年及其地质意义

志留系是塔里木盆地第一套砂岩储层广泛分布的沉积盖层,其沉积来源与成因对志留纪构造演化及周边造山带的研究具有重要意义。塔中地区3个志留系样品的碎屑锆石LA?ICP?MS U?Pb定年研究表明,志留系具有比较集中的二期物源年龄：南华纪中期、古元古代中期。碎屑锆石测定的年龄表明塔中志留系物源均来自前寒武纪,塔中东部源区方向的塔南隆起基底在奥陶纪已隆升成为蚀源区。大量的新元古代中期锆石年龄表明塔里木板块在新元古代时期可能与Rodinia超大陆具有相似的聚合与裂解演化史。     

Tracing the 850-Ma continental flood basalts from a piece of subducted continental crust in the North Qaidam UHPM belt,NW China

A Paleozoic ultrahigh-pressure metamorphic (UHPM) belt extends along the northern margin of the Qaidam Basin, North Tibetan Plateau. Eclogites in the Yuka eclogite terrane, northwest part of this UHPM belt, occur as blocks or layers of varying size intercalated with granitic and pelitic gneisses. These eclogites have protoliths geochemically similar to enriched-type mid-ocean ridge basalts (E-MORB) and oceanic island basalts (OIB). On the basis of Ti/Y ratios, they can be divided into low-Ti and high-Ti groups. The low-Ti group (LTG) eclogites exhibit relatively low TiO₂ (most <2.5 wt%) and Ti/Y (<500) but comparatively high Mg# (48–55), whereas the high-Ti group (HTG) eclogites have high TiO₂ (most >2.5 wt%) and Ti/Y (>500) but lower Mg# (46–52). Zircons from two eclogite samples gave a magmatic crystallization (protolith) age of ∼850 Ma and a UHPM age of ∼433 Ma. The occurrence, geochemical features and age data of the Yuka eclogites suggest that their protoliths are segments of continental flood basalts (CFBs) with a mantle plume origin, similar to most typical CFBs. Our observation, together with the tectonic history and regional geologic context, lend support for the large scale onset of mantle plume within the Rodinia supercontinent at ∼850 Ma. The Qaidam block is probably one of the fragments of the Rodinia supercontinent with a volcanic-rifted passive margin. The latter may have been dragged to mantle depths by its subducting leading edge of the oceanic lithosphere in the Early Paleozoic.     

多频测深初探

在频率域测深的基础上,提出了多频测深方法,实现一机多频同时观测的目的,以提高观测速度。本文讨论了多频观测方法的理论依据及工作特点,并提示实现这种观测的方案。     

Data processing and initial results from the CE-3 Extreme Ultraviolet Camera

The Extreme Ultraviolet Camera(EUVC) onboard the Chang'e-3(CE-3)lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions(He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius(RE) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.     

正确测定望远镜光能集中度的方法

正确测定望远镜光能集中度的方法苏定强（中国科学院南京天文仪器研制中心，南京２１００４２）主题词天文光学－望远镜－光学检验天文望远镜广泛采用的象质判据是光能集中度，即一定比例的光能量集中在多大的圆中。例如，七十年代的优秀望远镜光能集中度的标准是８０％的...     

水下拖曳系统运动姿态仿真研究

采用凝集参数法建立了水下拖曳系统的三维离散模型,该模型由一系列的质量点和不计重量的弹簧组成.采用数学模型编程对NCEL浮球实验和四个典型拖曳系统进行了仿真计算.计算结果表明此数学模型具有一定的理论意义和工程实用价值.     

东白令海三种经济鲽类捕捞群体结构与生长特性比较

对东白令海水域双线鲽(Lepidopsetta bilineata)、太平洋拟庸鲽(Hippoglosso-ides elassodon)和阿拉斯加鲽(Pleuronectes quadrituberculata)等三种经济鲽类的捕捞群体结构和生长特性进行比较。得出结论是:(1)捕捞群体结构复杂;(2)渐近体长和渐近体重较大、寿命长、K值小;(3)雌鱼比雄鱼个体大、生长快、寿命长;(4)三种鲽类的捕捞群体结构和生长特性有明显差异。     

An acoustic-wave theory for casing bond evaluation using viscoelastic slip boundary modeling

Slip boundary condition is commonly utilized to model elastic wave propagation through layered earth media. The same approach is used here to characterize acoustic wave propagation along a cased borehole with various cement bond conditions. By modeling the cement layer between casing and formation as a viscoelastic slip interface with complex coupling rigidity parameters, one can not only reduce the complexity in the classical elastic wave modeling of the problem, but also efficiently model various complicated wave phenomena that are difficult for the existing modeling. More specifically, the new theory can well describe the effect of the cement bond condition change and the location of the change (i.e., whether it is in the first interface between casing and cement, or the second interface between cement and formation) on the acoustic waves, demonstrating the good modeling capability and predicting power. Application of the theory to field data shows that the theory can correctly model the acoustic wave characteristics and interpret the cement bond condition, thus providing a useful fundament theory for casing bond evaluation using acoustic logging.     

The Co-seismic Response of Underground Fluid in Yunnan to the Nepal MS8.1 Earthquake

In this paper, statistics are taken on the co-seismic response of underground fluid in Yunnan to the Nepal M_S8.1 earthquake, and the co-seismic response characteristics of the water level and water temperature are analyzed and summarized with the digital data. The results show that the Nepal M_S8.1 earthquake had greater impact on the Yunnan region, and the macro and micro dynamics of fluids showed significant co-seismic response. The earthquake recording capacity of water level and temperature measurement is significantly higher than that of water radon and water quality to this large earthquake; the maximum amplitude and duration of co-seismic response of water level and water temperature vary greatly in different wells. The changing forms are dominated by fluctuation and step rise in water level, and a rising or falling restoration in water temperature. From the records of the main shock and the maximum strong aftershock,we can see that the greater magnitude of earthquake, the higher ratio of the occurrence of co-seismic response, and in the same well, the larger the response amplitude, as well as the longer the duration. The amplitude and duration of co-seismic response recorded by different instruments in a same well are different.Water temperature co-seismic response almost occurred in wells with water level response, indicating that the well water level and water temperature are closely related in co-seismic response, and the well water temperature seismic response was caused mainly by well water level seismic response.