Experimental Seasonal Forecast of Monsoon 2005 Using T170L42 AGCM on PARAM Padma

As a part of the Experimental Extended Range Monsoon Prediction Experiment, ensemble mode seasonal runs for the monsoon season of 2005 were made using the National Centre for Environmental Prediction (NCEP), T170L42 AGCM. The seasonal runs were made using six initial atmospheric conditions based on the NCEP operational analysis and with forecast monthly sea-surface temperature (SST) of the NCEP Coupled forecast system (CFS). These simulations were carried out on the PARAM Padma supercomputer of Centre for Development of Advanced Computing (C-DAC), India. The model climatology was prepared by integrating the model for ten years using climatological SST as the lower boundary. The climatology of the model compares well with the observed, in terms of the spatial distribution of rainfall over the Indian land mass. The model-simulated rainfall compares well with the Tropical Rainfall Measuring Mission (TRMM) estimates for the 2005 monsoon season. Compared to the model climatology (7.81 mm/day), the model had simulated a normal rainfall (7.75 mm/day) for the year 2005 which is in agreement with the observations (99% of long-term mean). However, the model could not capture the observed increase in September rainfall from that of a low value in August 2005. The circulation patterns simulated by the model are also comparable to the observed patterns. The ensemble mean onset is found to be nearer to the observed onset date within one pentad.     

牙鲆种群动态及其资源管理

本文根据1980—1986年间鱼类生物学参数测定,结合体长分布资料的模拟分析,研究黄、渤海区牙鲆种群年龄结构、死亡动态以及在不同年龄和死亡率条件下世代资源生物量变化的规律。模型分析结果表明,当F=1.0和t_c=6.0a时,单位补充量最大群体产量为1492g。由此认为,现阶段牙鲆资源利用的最佳策略是通过增殖放流,增加资源补充;同时应适当控制捕捞压力,减少渔具对幼鱼资源的破坏并增设繁殖保护区,以追求最大持续产量。     

T17断块岩性地层油气藏高效勘探开发模式研究

断陷湖盆缓坡带是油气运移的优势指向区,具备形成岩性地层油气藏的优越条件.本文采用地球物理技术与石油地质分析相结合的方法,分析了T17断块岩性地层油气藏的地质特征与油气展布规律,认为：（1）油气成藏受不整合面、岩性及构造因素综合控制;(2)单个含油砂体的油层在上倾部位受储层超覆尖灭线控制,下倾方向受油水界面控制;(3)多个含油砂体叠和构成了岩性地层油气聚集区带,整个区带油气层纵向上呈阶梯状产出,平面上由构造低部位向构造高部位呈条带状展布.据此,总结该区油气藏的高效勘探开发模式,并应用到该断块的勘探开发实践中,取得了较好的效果.     

Spinel–sapphirine–quartz bearing composite inclusion within garnet from an ultrahigh-temperature pelitic granulite: Implications for metamorphic history and P–T path

We report here a multiphase mineral inclusion composed of quartz, plagioclase, K-feldspar, sapphirine, spinel, orthopyroxene, and biotite, in porphyroblastic garnet within a pelitic granulite from Rajapalaiyam in the Madurai Granulite Block, southern India. In this unique textural association, hitherto unreported in previous studies, sapphirine shows four occurrences: (1) as anhedral mineral between spinel and quartz (Spr-1), (2) subhedral to euhedral needles mantled by quartz (Spr-2), (3) subhedral to anhedral mineral in orthopyroxene, and (4) isolated inclusion with quartz (Spr-4). Spr-1, Spr-2, and Spr-4 show direct grain contact with quartz, providing evidence for ultrahigh-temperature (UHT) metamorphism at temperatures exceeding 1000 °C. Associated orthopyroxene shows high Mg/(Fe + Mg) ratio ( 0.75) and Al₂O₃ content (up to 9.6 wt.%), also suggesting T > 1050 °C and P > 10 kbar during peak metamorphism.

Coarse spinel (Spl-1) with irregular grain morphology and adjacent quartz grains are separated by thin films of Spr-1 and K-feldspar, suggesting that Spl-1 and quartz were in equilibrium before the stability of Spr-1 + quartz. This texture implies that the P–T conditions of the rock shifted from the stability field of spinel + quartz to sapphirine + quartz. Petrogenetic grid considerations based on available data from the FMAS system favour exhumation along a counterclockwise P–T trajectory. The irregular shape of the inclusion and chemistry of the inclusion minerals are markedly different from the matrix phases suggesting the possibility that the inclusion minerals could have equilibrated from cordierite-bearing silicate-melt pockets during the garnet growth at extreme UHT conditions.     

对照组和雌核发育牙鲆血清中睾酮与雌二醇水平的比较

采用放射性免疫方法测定和比较了人工诱导的雌核发育牙鲆（Paralichthys olivaceus）与对照组牙鲆血清中睾酮（T）和雌二醇（E2）水平。研究发现, 雌核发育牙鲆个体中的T 含量显著高于对照组牙鲆个体（P〈0.05）, 而其E2 含量则略低于对照组个体; 在雌核发育牙鲆中, 卵巢发育不正常的个体比发育正常的...     

1993—2001年全球海面高度变化特征

应用TOPEX／POSEIDON（T／P）卫星高度计测高资料，对全球海洋的海面变化特征进行了分析，结果表明，1993年1月－2001年6月期间，全球海平面呈现上升的态势；全球平均海平面高度的平均上升速率约为1．2mm/a；海温的变化是引起海平面变化的重要原因，便其对海平面抬升的贡献不到50％。海平面的变化具有很强的地域特征。海平面变化的空间分布特征受风应力异常特别是纬向风应力异常的空间分布影响较大。     

Deep subduction of mantle-derived garnet peridotites from the Su-Lu UHP metamorphic terrane in China

Garnet peridotites from the southern Su‐Lu ultra‐high‐pressure metamorphic (UHPM) terrane, eastern China, contain porphyroblastic garnet with aligned inclusions comprising a low‐P–T mineral assemblage (chlorite, hornblende, Na‐gedrite, Na‐phlogopite, talc, spinel and pyrite). Orthopyroxene porphyroblasts show fine exsolution lamellae of clinopyroxene and minor chromite. A clinopyroxene inclusion in garnet shows some orthopyroxene exsolution lamellae. Both the rims of porphyroblastic pyroxene and garnet and the matrix pyroxene and garnet crystallized at the expense of olivine. This is interpreted as a result of metasomatism of the peridotites by an SiO₂‐rich melt at UHP conditions. A chromian garnet further overgrew on the rims of the garnet. The X_Mg values (Mg/(Mg+Fe)) of porphyroblastic garnet decrease from core to rim and vary in different peridotite samples, while the compositions of both the porphyroblastic and the matrix pyroxene are similar in terms of Ca–Mg–Fe. The Mg‐rich cores of porphyroblastic garnet and orthopyroxene record high temperatures and pressures (c. 1000 °C, ≥5.1 GPa), whereas the matrix minerals, including the rims of porphyroblasts, record much lower P–T (c. 4.2 GPa, c. 760 °C). Sm–Nd data give apparent isochron ages of c. 380 Ma and negative ε_Nd(0) values (c.?9). These dates are considered meaningless due to isotopic disequilibrium between garnet cores and the rest of the rocks. The isotopic disequilibrium was probably caused by metasomatism of the peridotites by melt/fluids derived from the coevally subducted crustal materials. On the other hand, the Rb–Sr isotopic systems of phlogopite and clinopyroxene appear to have reached equilibrium and record a cooling age of c. 205 Ma. It is suggested that the garnet peridotites were originally emplaced into a low‐P–T environment prior to the c. 220 Ma continental collision, during which they were subducted together with crustal rocks to mantle depth and subjected to UHP metamorphism. An important corollary is that at least some of the coevally subducted crustal rocks in the Su‐Lu terrane have been subjected to peak metamorphism at P–T conditions much higher than presently estimated (≥2.7 GPa, ≤800 °C).     

Significance of post‐peak metamorphic reaction microstructures in the ultrahigh temperature Eastern Ghats Province,India

Ultrahigh temperature (UHT) granulites in the Eastern Ghats Province (EGP) have a complex P–T–t history. We review the P–T histories of UHT metamorphism in the EGP and use that as a framework for investigating the P–T–t history of Mg–Al‐rich granulites from Anakapalle, with the express purpose of trying to reconcile the down‐pressure‐dominated P–T path with other UHT localities in the EGP. Mafic granulite that is host to Mg–Al‐rich metasedimentary granulites at Anakapalle has a protolith age of c. 1,580 Ma. Mg–Al‐rich metasedimentary granulites within the mafic granulite at Anakapalle were metamorphosed at UHT conditions during tectonism at 960–875 Ma, meaning that the UHT metamorphism was not the result of contact metamorphism from emplacement of the host mafic rock. Reworking occurred during the Pan‐African (c. 600–500 Ma) event, and is interpreted to have produced hydrous assemblages that overprint the post‐peak high‐T retrograde assemblages. In contrast to rocks elsewhere in the EGP that developed post‐peak cordierite, the metasedimentary granulites at Anakapalle developed post‐peak, generation ‘2’ reaction products that are cordierite‐absent and nominally anhydrous. Therefore, rocks at Anakapalle offer the unique opportunity to quantify the pressure drop that occurred during so‐called M2 that affected the EGP. We argue that M2 is either a continuation of M1 and that the overall P–T path shape is a complex counter‐clockwise loop, or that M1 is an up‐temperature counter‐clockwise deviation superimposed on the M2 path. Therefore, rather than the rocks at Anakapalle having a metamorphic history that is apparently anomalous from the rest of the EGP, we interpret that other previously studied localities in the EGP record a different part of the same P–T path history as Anakapalle, but do not preserve a significant record of pressure decrease. This is due either to the inability of refractory rocks to extensively react to produce a rich mineralogical record of pressure decrease, or because the earlier high‐P part of the rocks history was erased by the M1 loop. Irrespective of the specific scenario, models for the tectonic evolution of the EGP must take the substantial pressure decrease during M2 into account, as it is probable the P–T record at Anakapalle is a reflection of tectonics affecting the entire province.     

Deep crustal growth of quartz, kyanite and garnet into large-aperture, fluid-filled fractures, north-eastern Connecticut, USA

Abstract A petrographic and petrological analysis of exceptionally well-preserved hydrothermal veins from the Merrimack synclinorium, north-eastern Connecticut, has been carried out in order to place new field-based constraints on fracture aperture dimensions and porosity in the lower continental crust. The veins preserve substantial open space today in outcrop, and contain mineral assemblages including subhedral to euhedral crystals of quartz, kyanite and almandine-rich garnet. Textural evidence indicates unequivocally that the vein minerals grew into macroscopic (mm- to cm-scale) open space between the vein walls. The veins are interpreted to have been large-aperture fractures along which significant advective fluid infiltration and chemical reaction occurred. The porosity of the rock mass due to open space between fracture walls today is c . 0.3%, but it could have been as large as several percent when the flow system was active. Quantitative thermobarometry results from vein mineral assemblages indicate that the fractures formed at pressures and corresponding crustal depths of c. 0.8 GPa and c. 30km, and temperatures of 550–600° C. The depth of fracture formation corresponds to published estimates of the maximum burial depth of the Merrimack synclinorium during the Acadian orogeny. The formation of large-aperture fractures could increase significantly the transient permeability of the deep crust, and therefore influence metamorphic heat and mass transfer.     

云南兰坪罗善铅锌矿控矿因素及成因

铅锌矿赋存于上三叠统三合洞组下段（T3s1）灰岩容矿岩层中及近南北向、北北东向、北西向断裂破碎带内,少数赋存在近东西向节理裂隙中,成因具多成矿阶段、多成矿物质来源特征,层位＋构造控制的中低温热液型铅锌多金属矿床.