以坡位为空间配置单元的流域管理措施情景优化方法

基于流域过程模型的BMP情景分析是当前流域管理措施评价、非点源污染控制等研究应用中广泛采用的方法,但其通常采用的BMP空间配置单元（地块、农场、水文响应单元或子流域）与坡面上的地形部位关系较弱,难以有效地根据坡面过程特点表达坡面上多种BMP之间的空间配置关系,影响了BMP情景优化效率和结果的合理性。为此,本文提出以坡位单元作为BMP空间配置单元,将各种BMP在不同坡位间合理的空间配置关系显式表达为基于坡位的空间配置规则,通过结合NSGA-II优化算法建立了一套基于坡位单元的BMP空间配置优化方法。应用案例表明,本文构建的基于坡位单元的BMP情景优化方法可有效利用基于坡位的空间配置规则进行BMP情景优化,优化所得的BMP空间配置方案更为合理,优化效率较高。     

Evaluation of soil physical properties of long-used cultivated lands as a deriving indicator of soil degradation,north Ethiopia

Soil degradation causes low land productivity. To tackle soil degradation, soil management practices have been implemented in the study area. However, less attention has been given to the management of physical soil quality. Hence, the objective of this study is to evaluate soil physical properties of long-used cultivated lands. Twelve Land Mapping Units (LMUs) were identified by overlaying slope and soil maps. Twelve composite and 12 undisturbed soil samples were collected from the 12 LMUs, and soil physical properties analyzed. Soil bulk density varied from 1.22 g cm^?3 in LMU3 to 1.68 g cm^?3 in LMU4. Available water capacity ranged from 0.09 in LMU4 to 0.17 in LMU3. Stability index (SI) values ranged from a low of 3.58 at LUM10 to 62.5 at LMU3; stability quotient (SQ) values ranged from 79.4 at LMU9 to 2782.8 at LUM3. Highest and lowest soil crust index values were found to be 1.53 in LMU5 and 0.29 in LMU9. This study indicated that poor soil management practice in the study area has caused soil physical degradation. Therefore, this study provides insight into improved land management of long-used cultivated land in the semi-arid region of the study area and other similar environments.     

Tectonic unit divisions based on block tectonics theory in the South China Sea and its adjacent areas

Identifying distinct tectonic units is key to understanding the geotectonic framework and distribution law of oil and gas resources. The South China Sea and its adjacent areas have undergone complex tectonic evolution processes, and the division of tectonic units is controversial. Guided by block tectonics theory, this study divide the South China Sea and its adjacent areas into several distinguished tectonic units relying on known boundary markers such as sutures(ophiolite belts), subduction-collision zones, orogenic belts, and deep faults. This work suggests that the study area is occupied by nine stable blocks(West Burma Block, Sibumasu Block, LanpingSimao Block, Indochina Block, Yangtze Block, Cathaysian Block, Qiongnan Block, Nansha Block, and Northwest Sulu Block), two suture zones(Majiang suture zone and Southeast Yangtze suture zone), two accretionary zones(Sarawak-Sulu accretionary zone and East Sulawesi accretionary zone), one subduction-collision zone(RakhineJava-Timor subduction-collision zone), one ramp zone(Philippine islands ramp zone), and six small oceanic marginal sea basins(South China Sea Basin, Sulu Sea Basin, Sulawesi Sea Basin, Banda Sea Basin, Makassar Basin, and Andaman Sea Basin). This division reflects the tectonic activities, crustal structural properties, and evolutionary records of each evaluated tectonic unit. It is of great theoretical and practical importance to understand the tectonic framework to support the exploration of oil and gas resources in the South China Sea and its adjacent areas.     

地勘单位企业化改制战略初探

本文在分析地勘单位改革现状的基础上,指出了地勘单位向企业化转变中的矛盾和问题,提出了实施企业化改制的战略目标及战略对策。     

Terrain mapping unit-based approach for sustainable agricultural development in India—an example from plains ecosystem at semi-arid interface

‘Green Revolution’ was adopted as National Agricultural Policy by the Government of India to meet the requirements for food grain self-sufficiency. Improved seeds, fertilizers and irrigation were provided as science and technology (S&T) inputs to the soil resource base of the country. Land use changes in order to increase the area of land under cultivation have resulted in sectoral imbalances. The introduction of irrigation, fertilizers and new seed varieties using the district as a unit of agricultural input and management, without consideration of moisture and pedogenetic requirements at the micro-level, have resulted in ecological imbalances and environmental degradation in some parts of the district. Intensive irrigation has resulted in water mining in some blocks, and over a period of years the upper aquifer has been lost and in parts of the Aligarh district water-logging and salinity development has taken place.This paper presents the concept of spatial information systems for sustainable agriculture to eliminate the overdose effect of S&T inputs in a land system such as the fragile ecosystem at the semi-arid border in India.The present study has attempted to integrate the natural resource endowments of lithology, soil, ground-water and geomorphology into terrain mapping units (TMUs). The geological, geomorphological and soil maps were generated using remotely sensed data. For ground-water, well logging was carried out and secondary data regarding depth to water-table were collated. The spatial modelling for depth to water-table was carried out using SURFER software. The files on geology, geomorphology, soil and depth to water-table were digitized and integrated to generate an illuminated model characterized by areas of homogeneity in terms of geology, geomorphology, soil and ground-water conditions to map the TMUs. Intergraph's Modular GIS Environment (MGE) software was used to integrate the multiple data base.For sustainable agriculture the natural boundaries represented by TMUs will be more appropriate as spatial units for the application of agricultural inputs and management practices for the land system, rather than villages, blocks and districts which have cultural boundaries. The methodology proposed will be useful for all ecosystems in semi-arid and arid regions.     

软弱层带夹泥物理力学特征的仿真研究

软弱层带夹泥物理力学参数是评价岩体稳定性的基础。研究表明,在天然围压条件下,软弱层带夹泥的物理力学性质与其所承受的围压具有良好的相关性。因此,本文提出应用土工压缩定律及重力压密机制在室内对夹泥的物理力学特征进行仿真研究,并对仿真效果进行了评价。这为软弱层带夹泥物理力学参数的评价、预测提供了新的途径。     

中更新世以来东海陆架的古环境

基于１９９６年中法合作在东海陆架进行的电火花单道地震调查资料,并与位于东海外陆架钻孔ＤＺＱ４对比,发现对应于氧同位素６期以来的六个地震地层与钻孔地层呈现很好的对应关系,其间共有四次海退－海进的沉积旋回。资料分析表明东海第四纪环境演变与全球气候冷暖变化所导致的海面升降直接相关。     

新生代以来中国大陆岩石圈尺度的大地构造分区

基于大陆根柱构造概念，讨论了新生代以来大陆岩石圈尺度的大地构造分枢，地壳浅部主要表现为３种形态，即西部挤压造山带、东部大陆裂谷带和中部克拉通块体群，它们分别对应山根与造山岩石圈根、地幔热柱和大陆（岩石圈）根，认为浅部构造开矿对对壳幔深部构造的一种响应，简述了地于岩石圈度的３个大地构造单元的软流圈     

In situ and laboratory investigations of fluid flow through an argillaceous formation at different scales of space and time, Tournemire tunnel, southern France

In the context of a research and development program on waste disposal, an experimental site (Tournemire tunnel, Aveyron, France) was selected by the French Institute for Nuclear Protection and Safety (IPSN) in order to undertake studies on potential fluid flow at different scales of space and time within a 250-m-thick argillaceous formation. The argillite has a low natural water content (~3–5%) and very low radii access porosity. Diffusion (tritiated water) coefficients (1×10^–12 to 2×10^–11 m²/s) and hydraulic conductivities derived from different types of laboratory tests (10^–14 to 10^–13 m/s) are characteristics of a very low-permeable rock. In situ hydraulic tests (including long-term hydraulic-head measurements) were used to obtain values for hydraulic head and hydraulic conductivity at a scale of 1–10 m (10^–13 to 10^–11 m/s). Despite uncertainties on these data (due to a scale factor, presence of fissures, and possible artefacts due to hydro-chemo-mechanical coupling), it is expected that fluid flow is essentially governed by diffusion processes. Identification of possible natural flows at larger scales of time and space was investigated using natural isotopic tracers from interstitial fluids. Modelling, based on the deuterium profile along the clay formation and assuming pure diffusion processes, provides estimations of possible flow times. However, lack of knowledge concerning the past geological evolution of the site and the possible role of a fracture network do not permit reduction of uncertainties on these estimations at this stage. Electronic Publication