青藏高原多年冻土区沥青路面下融化盘形成变化特征

在青藏高原多年冻土区，沥青路面的辅设改变了地表与大气之间的热交换关系，尤其是路面水分蒸发量大量减少，致使路面突然升高，多年冻土层内能量积蓄增多，地温升高，上奶宵年下降。最终在路基下多年冻土顶板上形成融化夹层，并随时间延长，多年冻土顶板下降，融化夹层逐年扩大，多年冻土地下冰融化，路面破坏，严重影响道路运营。     

The Chahe Copper Deposit—Its Age and Genesis

The Chahe copper deposit occurs in the Early Proterozoic metamorphic series in the area of Chahe and its chalcopyrite yielded a Pb−Pb isochron age of 951±36 Ma, providing evidence for copper mineralization at the early stage of the Jinning movement. The ore-forming material came from terrestrial clastic sediments and marine volcanic eruption and the ores were deposited in a relatively open beach environment. The Jinning movement led to folding and metamorphism of country strata, as well as to the rebomilization and transport of copper, resulting in ore deposition in structurally weak locations. This deposit is a volcano-sedimentary metamorphic deposit.     

甘肃及邻近地区ML与MS震级问题的探讨

甘肃及邻近地区Ｍ＿Ｌ与Ｍ＿Ｓ震级问题的探讨众所周知，震级问题是国内外地震学家非常关心并一直在探讨的重要课题。由实际观测资料发现，对于甘肃及邻近地区Ｍ＿Ｓ≥４．０的地震（中长周期和短周期仪器都能记上的情况下）由短周期仪测定的体波震级Ｍ＿Ｌ换算出的面波震...     

甘肃及邻区台网MD震级公式的研究

目前,在我国相继有不少地震台站(网)研究了适合该地区的测定持续时间震级的方法,并建立了相应的公式。本文利用兰州有线传输台网记录的甘肃及邻区的470个地震资料,建立了6个有线传输台和武威无线传输台网的4个子台的M_D震级公式,初步建立了兰州电传台网的M_D震级系统。本文还对M_D与M_L两种震级测量精度做了初步评价,简要分析了放大倍数v对M_D震级的影响。     

Low-Pressure Metamorphism of Granulite Facies in an Early Proterozoic Orogenic Event in Central Inner Mongolia

According to the kinds of feldspar and rock associations in the Ai-rich gneisses, the low-pressure metamorphic crust of the Early Proterozoic granulite facies in central Inner Mongolia can be divided into southern and northern belts which are composed of six rock associations. They represent the relevant rock sequences of the layered metamorphic rock series formed under specific metamorphic temperature and pressure conditions as well as tectonic environments. Mineral inclusions and reaction texture have recorded that the medium-temperature high-pressure mineral assemblages are replaced by the high-temperature low-pressure mineral assemblages, thus, giving rise to: garnet+quartz→ hypersthene+plagioclase; kyanite→sillimanite and garnet+kyanite/sillimanite+quartz→cordierite. The deformation fabrics of the rocks, the change of mineral assemblages and the PTt path of metamorphism indicate that the contempranceous high-temperature normal-slip ductile shearing is the main cause of the formation of the low-pressure metamorphic crust of granulite facies. In the orogenic event, the co-action of thrusting and extension resulted in the change of a medium-temperature high-pressure metamorphic environment into the high-temperature low-pressure metamorphic conditions.     

麻粒岩相区地质研究现状及评述

构成世界各大陆基底的前寒武纪高级变质区或称麻粒岩相区,是下部地壳的代表。它的研究不仅具有实际意义(赋存有大量矿产),而且具有极大的理论价值。因而对这一课题的研究已成为各国地质界的热门。当前,对这一领域的研究主要集中于以下几个方面:①前寒武纪麻粒岩相区以及下部地壳的性质及其组成;②麻粒岩相的形成条件和机制,温压条件测定方法的选择;③麻粒岩相区变质流体的性质及其作用;④下部地壳的地球化学研究;⑤麻粒岩相区地质学和岩石学研究及它们的动力学模拟(P-T-t轨迹)。     

Changes and spatial patterns of the differences between ground and air temperature over the Qinghai–Xizang Plateau

The difference between ground soil and air temperature (Ts-Ta) was studied by using the data of ground and air temperature of 99 stations over the Qinghai–Xizang (Tibet) Plateau from 1960 to 2000,and its spatial distribution and time changing tendency have been diagnosed by principal component analysis and power spectral analysis methods. The results show that the values of (Ts-Ta) are the maximum in June and the minimum in December. The first three loading eigenvectors, which reflect the main spatially anomalous structure of (Ts-Ta) over the Qinghai–Xizang Plateau, contain the contrary changing pattern between the north-western and the southeastern regions, the pattern response of the sea level elevation and the geography, and the pattern response of the distribution of the permafrost. There are four patterns of time evolution including the patterns of monotonous increasing or decreasing trends, the basic stability pattern and the parabola pattern with the minimum value. (Ts-Ta) has a periodic variation about 2 years. According to the spatial distribution of the third loading eigenvectors of (Ts-Ta) over the Qinghai–Xizang Plateau in cold season, the permafrost re-sponse region and the seasonal frozen ground response region are identified.     

灰色聚类分析在煤炭资源有效保障能力评价中的应用

在灰色系统理论与煤炭资源评价实践有机结合的基础上,讨论了煤炭资源评价单元的灰色特征,分析了灰色聚类分析应用于煤炭资源评价的原理,给出了煤炭资源评价中的灰色聚类分析的计算方法。以贵州省9个煤炭资源评价单元为例,参考18个评价指标,按照既定的优、良、可、差等级划分标准,计算出其综合优度值,得到评价结果为4良、4可、1差,并给出开发的先后顺序。结果表明,该方法具有较大的实用性。      

洞庭湖湖区水质时空演化(1983-2004年)

根据洞庭湖湖区的1983-2004年的水质监测数据,参照GB3838-2002中Ⅲ类水质标准,运用内梅罗水污染指数法进行水质评价,分析了洞庭湖湖区22年来的水质时空变化.结果表明:洞庭湖湖区水质污染在时间上呈有升有降的波动变化.洞庭湖湖区丰水期和洪水期的水质较差,但是从2002年以后,丰水期的水质逐渐好于平水期.污染空间变化表现为入湖河道的污染程度高于湖体,湖体污染呈西洞庭湖的污染较为严重,南洞庭湖其次,东洞庭湖的水质仍较好的格局.