Digital Simulation on Convergence Tendency between Southwest Tienshan and Pamirs-West Kunlun Systems and Its Significance

The collision between India plate and Eurasia continent 55 Ma ago caused the convergence between Southwest Tienshan and Pamirs tectonic systems, and conclusions by other researchers also suggest that the convergence will continue. Studies on the collision between these systems are helpful to the knowledge of the history and the tendency of the in-land tectonics since Cenozoic and are important in science and the real world as for environment changes, resources and energy reform, and forecast of earthquakes. For this reason, by means of digital modeling, on the basis of crustal shortening rate, crustal motion rate and data of physical properties of rocks, with the help of the FE (finite element) theory-based marc software, the United States, we address on the tendency of the convergence in this area in almost 10 Ma and draw a conclusion that the converged borders move northward and stretch southeast. The Southwest Tienshan will move more slowly and suffer less deformation than the Pamirs-West Kunlun (昆仑) system. The Pamirs-West Kunlun system will rotate counterclockwise while moving northward and extending westward.     

Solar insolation driven periodicities in southwest monsoon and its impact on NE Arabian Sea paleoceanography

In the northeastern(NE) Arabian Sea,the fluctuation in terrestrial and freshwater runoff directly depends on southwest monsoon(SWM) precipitation as well as the meltwater flux provided by Indus River.Therefore,analysis of multi-proxy spectral signatures was carried out to trace the high-resolution SWM periodicities and their influence on the productivity,regional sea level fluctuations and depositional processes in the NE Arabian Sea.The time series data of stable isotopes of oxygen(δ~(18)O_(G.ruber)).carbon(δ~(13)C_(G.ruber) and δ~(13)C_(org)) and nitrogen(δ~(15)N).Total Organic Carbon(TOC),planktic-benthic foraminiferal ratio(P/B ratio) and63 μm coarse fraction(CF) were used from two coastal sedimentary cores located offshore Saurashtra,NE Arabian Sea(Core SK-240/485 having 88 m water depth;Core GC/SK-240/496 having 174 m water depth).The REDFIT based spectral analysis recorded significant periodicities(90% significance) in δ~(18)0 time series centered at~1609,~667,~525,~296,~290 and~256 years.Further,the significant periodicities recorded in carbon isotopes time series(δ~(13)C_(G.ruber) and δ~(13)C_(org))centered at~681,~512,~471,~452,~438,~360,~292,~275,~269,~245 and~209 years.The significant periodicities in TOC include~471 and-322 years whereas δ~(15)N time series recorded significant periodicity centered at-360 years.The significant periodicities in P/B ratio time series centered at~512,~388,~304,~250,~235,~217,~152,~139 and~135 years while CF recorded~268,~216,~209,~198,~188,~173 and~140 years significant periodicities.The observed periodicities in the multi-proxy record consist of similar cycles(within the radiocarbon dating error) which also natch with previously reported solar insolation influenced SWM and other global and regional cycles.Further,the stationarity of the data has been verified using wavelet analysis and shows similar periodicities as observed in REDFIT analysis.Thereafter,the depositional behaviour was studied using correlation analysis of the common periods of δ~(18)0 time series of both the cores.The result suggests that the depositional behaviour was different for both the core sites during the early Holocene and became similar during the middle Holocene.The correlation analysis of Total Solar Index(TSI) with δ~(18)O time series reveals a significant correlation with the core SK-240/485 whereas an insignificant correlation with the core GC/SK-240/496.These observations suggest that the solar insolation has been a leading factor responsible for the SWM trends during the Holocene which may have further influenced the productivity.regional sea level fluctuations and depositional conditions in the NE Arabian Sea.However,these trends are better preserved in shallow marine sediments as compared to the deeper marine sediments.     

海底管线管跨段涡激振动响应的实验研究

海底管线管跨段的涡激振动,是引发海底管线失效的主要因素之一,尤其是管跨在涡激振动下的“频率锁定”现象,是导致管线断裂失效的主要原因,也是在设计和维护管理中必须要避免的状态。影响管跨涡激振动响应规律的因素很复杂,因此,模型实验是研究和探索其规律的主要手段。为了探索海流运动对管跨动力响应的影响规律,在实验水槽中,分别对管跨在稳定流和随机流的作用下,管跨的动力响应规律进行了测定,本文对实验结果进行了分析的基础上,总结了“频率锁定”现象出现的条件,提出了在海底管线的可靠性设计和管道理中应采取的相应措施。     

涡旋相互作用及其对强度和路径的影响

研究一个台风涡旋和一个低压涡旋之间的相互作用。该相互作用使低压涡旋强度 衰减的速率显著变慢，使低压涡旋滞留在初始位置附近的时间显著加长。在低压涡旋强度 演化和路径变化的过程中，显示出清楚的临界点现象。     

Prioritizing conservation potential of arid-land montane natural springs and associated riparian areas

Using inventory data and input from natural resource professionals, we developed a classification system that categorizes conservation potential for montane natural springs. This system contains 18 classes based on the presence of a riparian patch, wetland species, surface water, and evidence of human activity. We measured physical and biological components of 276 montane springs in the Oscura Mountains above 1450 m and the San Andres Mountains above 1300 m in southern New Mexico. Two of the 18 classes were not represented during the inventory, indicating the system applies to conditions beyond the montane springs in our study area. The class type observed most often (73 springs) had a riparian patch, perennial surface water, and human evidence. We assessed our system in relation to 13 other wetland and riparian classification systems regarding approach, area of applicability, intended users, validation, ease of use, and examination of system response. Our classification can be used to rapidly assess priority of conservation potential for isolated riparian sites, especially springs, in arid landscapes. We recommend (1) including this classification in conservation planning, (2) removing deleterious structures from high-priority sites, and (3) assessing efficiency and use of this classification scheme elsewhere.     

探索川西南地区二叠系阳新统断层裂缝储集流体规律

本文通过对75口断层井勘探成效的分析研究,揭示了阳新统内逆断层有效裂缝分布于脆性岩层接触的断层面附近,储集流体性质随断点层位的新老变化而变化,即断点层位新以产气为主、层位老以产水为主的客观地质现象。这一规律的发现对提高勘探获气率和控制断层气井的无水采气期,具有重要的现实意义。     

西南涡与鄂南暴雨的关系及其预报

利用1970—1995年咸宁气象资料，分析了鄂南西南涡暴雨的气候特征及环流形势，并归纳了相应的暴雨短期预报模型。     

闽西南坳陷内石炭纪海相火山岩类的空间分布及其意义

闽西南坳陷在石炭纪时，演化至一个重要的发展阶段。于海盆形成初期，随着坳陷加深，发育了一条呈北东东向横贯坳陷区的横张断裂带，使盆底开裂、引起海底火山活动。此带可称为上杭-德化构造、火山活动带。该带与南平-宁化构造带基本平行，后者作为控制闽西南坳陷北部的边界性构造，很可能也控制了上杭-德化构造、火山活动带的生成。在龙岩马坑等地，断裂已深切至上地幔，导致玄武岩浆的喷溢，而马坑铁矿正处于坳陷最深部位。福建已知的重要铁矿几乎均位于此带上，因此，是重要的铁矿成矿带。     

丽江地震前后西南地区定点形变变化的特点分析

研究了1996年2月3日丽江7．0级地震前后西南地区地倾斜观测的特点及与中强地震活动之间的关系。研究结果表明，丽江地震后西南地区地倾斜变化幅度与区域地震活动水平具有逐年减弱的趋势，丽江地震后5年内中强地震都发生在快速变形以后回复的时间段内，而5年之后，中强地震则往往发生在一些快速变化的极值点时刻。在对每次中强地震前形变特征分析的基础上，还研究了短期形变前兆对地震的触发机制，给出了每次地震前短期形变迁移的速度分布。最后讨论了短期形变前兆的非同步性、非遍历性、不可重复性及无记忆性等特性。尽管这些特性可能使得经验地震预测变得更为艰难，但是认识这些特性将可能帮助找到新的预测途径。     

低涡与怀柔暴雨

对产生怀柔县暴雨的三类低涡（蒙古低涡、西北涡和西南涡）进行了统计分析。对各类低涡暴雨的个例对比分析发现，三类低涡暴雨有相同的不稳定度和水汽条件，但垂直运动条件则不同，这些为暴雨预报提供了依据。