松辽盆地东南缘中生代火山岩及其盆地形成的构造背景

松辽盆地是我国著名的中生代盆地，在盆地的深部及其周边存在着大量火岩，在空间上和时间上火山岩和盆地之间有着密切的关系该区火山岩主要形成于晚侏罗世和早白垩世火山岩具有高钾的特征，为钙碱性火山岩系列和钾玄岩系列其岩石类型主要有：钾玄岩、响岩质碱玄岩、橄榄粗安岩、安粗岩、粗面岩、流纹岩火山岩的ＲＥＥ和不相容元素分布特点与造山带火山岩不相容元素的特点相似，在构造判别图解上，本区火山岩落在与俯冲作用有关的造山带火岩区域中，对火山岩的特征分析表明，本区火山岩与俯冲作用有关，本区总体构造背景与伊佐奈琦板块向东亚大陆腐冲作用有关，是一个冲造山带的构造背景     

内蒙东红胜花岗岩-绿岩带中韧性变形带的初步研究

该花岗岩—绿岩带位于内蒙武川县境内,是华北陆台北缘花岗岩—绿岩带的一部分。花岗岩—绿岩带主要由花岗岩及花岗质片麻岩系组成,构成绿岩带主体的上壳岩系被花岗质岩石所侵入、分离,呈似层状、大透镜状漂浮于花岗质岩石“海洋”之中。通过实地测量、构造解     

扬子大陆的陆内俯冲与大陆的缩小──由白云母（二云母）花岗岩推导

本文简要地论述了白云母（二云母）花岗岩是陆内俯冲的岩石学记录。华南大陆与天水－雅江地带广泛分布中生代王云母花岗岩侵作入体，已有的同位素年龄范围为２４５～１２２Ｍａ，与此同时，它们两侧的扬子大陆发育前陆褶皱带，这种成对性及其构造配置表明，扬子大陆曾向华南大陆与松潘—甘孜褶皱带发生过陆内俯冲作用。基于二云母花岗岩带的总宽度（约６５０ｋｍ），估算扬子大陆最小的总俯冲量（指宽度）至少为６５０ｋｍ，扬子大陆现今宽度约６８０ｋｍ，这样，扬子大陆在中生代时期由于陆内俯冲作用缩小了约一半；另一可能方案是，消失的主要是夹持于扬子大陆与江南造山带之间的一个微大陆。扬子大陆与秦岭造山带之间的壳内构造边界不具陆内俯冲性质，而是逆冲推复一走滑构造带。在大地构造单元上，江南造山带与龙门山造山带应分属两个上叠大陆，而不属于扬子大陆。华南中生代造山带内侧属于高喜马拉雅型陆内俯冲带（缝合带内无蛇绿岩伴生），而不是雅鲁藏布江型（缝合带内有蛇绿岩伴生）。陆内俯冲作用是华南大陆形成的主要机制之一。此外，它经受过晚元古代和加里东期陆内俯冲事件，可能属于雅鲁藏布江型。多次陆内俯冲和白云母（二云母）花岗岩的形成导致亲陆壳金属元素富集，可能是华南Ｗ－Ｓｎ     

PBDEs in the blubber of marine mammals from coastal areas of São Paulo, Brazil, southwestern Atlantic

Limited information is available in the literature on the levels of brominated flame retardants in the southern hemisphere. This study presents concentrations of polybrominated diphenyl ethers (PBDEs) in the blubber of small cetaceans from the coast of São Paulo (Brazil), southwestern Atlantic. PBDE levels were highest in Stenellafrontalis (770 ng g⁻¹ lipid) followed by Stenobredanensis (475 ng g⁻¹ lipid), Sotaliaguianensis (65.6 ng g⁻¹ lipid), Tursiopstruncatus (64.2 ng g⁻¹ lipid) and Pontoporiablainvillei (60.3 ng g⁻¹ lipid). In general, continental shelf individuals exhibited higher contamination than inshore animals. This might be related to larger prey items consumed by continental shelf dolphins. The pattern of contamination indicates that Penta-BDE commercial mixtures are a major source of PBDEs to top predators in the southwestern Atlantic. Congeners found in Octa-BDE formulations were not detected in the investigated animals.     

Microencapsulation of okadaic acid as a tool for studying the accumulation of DSP toxins in mussels

The possibility and effectiveness of microencapsulation of okadaic acid (OA) in gelatin-acacia microcapsules has been studied. The encapsulation efficiency was higher than 33%. The microcapsules were shown to be very stable, not leaching more than 9% of the encapsulated OA in a 20-h period. OA from the microcapsules was absorbed by the mussels very efficiently, accumulating--after 3 days of feeding and one of depuration--65% of the OA in microcapsules and 22% of the total OA used at the beginning of the microencapsulation process. These efficiencies and the possibility of encapsulating single DSP toxins and derivatives constitute a valuable tool for the study of the accumulation and biotransformation of DSP toxins in bivalves.     

晚元古代和古生代的潮汐,月球后退与地球自转

元古界Ｂｉｇ Ｃｏｔｔｏｎｗｏｏｄ组，新元古界Ｆｌｉｎｄｅｒｓ岭地区Ｅｌａｔｉｎａ组，宾夕法尼亚系下统Ｐｏｔｔｓｖｉｌｌｅ组和Ｍａｎｓｆｉｅｌ组中的潮汐韵律表明，月轨道的后退速率为ｄξ／ｄｔ－ｋ２ｓｉｎ，ｋ２而且这一速率从晚前寒武纪以来基本保持恒定。     

Photochemical modeling of Titan's atmosphere

We have developed a new photochemical model of Titan's atmosphere which includes all the important compounds and reactions in spherical geometry from the surface to 1240 km. Compared to the previous model of Yung et al. (1984, Astrophys. J. Suppl. 55, 465-506), the most significant recent change in the reactions used is the updated methane photodissociation scheme (Mordaunt et al. 1993, J. Chem. Phys. 98(3), 2054-2065). Moreover, the transfer of the solar radiation in the atmosphere and the photolysis rates have been calculated by using a Monte Carlo code. Finally, the eddy diffusion coefficient profile is adjusted in order to fit the mean vertical distribution of HCN retrieved from millimeter groundbased observations of Tanguy et al. (1990, Icarus, 85, 43-57) using new values for the boundary flux of atomic nitrogen (Strobel et al. 1992, Icarus 100, 512-526). We have run the model in both steady-state and diurnal modes, with 62 speices involved in 249 reactions. There is little difference between diurnal and steady-state results. Overall our results are in a closer agreement with the abundances inferred from the Voyager infrared measurements at the equator than the Yung et al. results. We find that the catalytic scheme for H recombination invoked by Yung et al. only slightly improves the model results and we conclude that this scheme is not essential to fit observations.     

Episodic ocean-induced CO2 greenhouse on Mars: implications for fluvial valley formation

Pulses of CO2 injected into the martian atmosphere more recently than 4 Ga can place the atmosphere into a stable, higher pressure, warmer greenhouse state. One to two bar pulses of CO2 added to the atmosphere during the past several billion years are sufficient to raise global mean temperatures above 240 or 250 K for tens to hundreds of millions of years, even when accounting for CO2 condensation. Over time, the added CO2 is lost to carbonates, the atmosphere collapses and returns to its buffered state. A substantial amount of water could be transported during the greenhouse periods from the surface of a frozen body of water created by outflow channel discharges to higher elevations, despite global temperatures well below freezing. This water, precipitated as snow, could ultimately form fluvial valleys if deposition sites are associated with localized heat sources, such as magmatic intrusions or volcanoes. Thus, if outflow channel discharges were accompanied by the release of sufficient quantities of CO2, a limited hydrological cycle could have resulted that would have been capable of producing geomorphic change sufficient for fluvial erosion and valley formation. Glacial or periglacial landforms would also be a consequence of such a mechanism.     

Dissolved gases in perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica

Measurements of dissolved N2, O2, Ar, CO2, and CH4 were made in perennially ice-covered Lake Hoare. Results confirm previous reports that O2 concentrations in the upper water column exceed atmospheric equilibrium and that N2 and Ar are supersaturated throughout the water column. The mean supersaturation of N2 was found to be 2.0 (+/- 0.37) and Ar was 3.8 (+/- 1.1). The ratios of N2/Ar (20.3 +/- 13.8), and O2/Ar (22.5 +/- 4.0) at the ice-water interface are consistent with those previously measured, suggesting that bubble formation is the main process for removing gas from the lake. However, the saturations of N2 and Ar greatly exceed those previously predicted for degassing by bubble formation only at the ice-water interface. The data support the hypothesis that removal of gas by bubbles occurs in the water column to a depth of 11 m in Lake Hoare. CO2 concentration increases from near zero at the ice-water interface to 80-100 times saturation at and below the chemocline at c. 28 m. There is considerable variability in the gas concentrations throughout the water column; samples separated in depth by one metre may vary by more than 50% in gas content. It is likely that this phenomenon results from the lack of turbulent mixing in the water column. Methane (c. 2 micrograms l-1) was detected below the chemocline and immediately above the sediment/water interface at a depth of 30 m. Samples from lakes Vanda, Joyce, and Miers, also show supersaturations of O2, N2, and Ar at levels similar to levels found in Lake Hoare.     

格尔木－额济纳旗地学断面走廊域地壳－上地幔岩石学结构与深部过程

基于岩石学研究与地球物理场的结合，提出了祁连山、柴达木与北山３个地区的壳幔岩石学结构．认为造山带加厚的下地壳与山根带分别由高压麻粒岩相与榴辉岩相岩石构成，对断面走廊域进行了岩石学填图．探讨了山根的形成与不对称、陆壳物质的分异与新莫霍界面的形成、造山岩石圈增厚机制、岩石围拆沉与玄武岩岩浆底侵作用等．讨论了青藏高原南、北缘岩石图增厚机制的差异及其岩石学标志．