应用GIS技术进行油气资源评价的探讨   总被引：10，自引：0，他引：10  

李艳春  王东坡 《世界地质》1998,17(3):49-53,104

简要介绍了地理信息系统（ＧＩＳ）概况,同时讨论了利用ＧＩＳ进行油气评价的可能性及优越性,并利用此法辽河外围盆地进行凹陷评价,建立了辽河外围盆地地质信息系统,最后应用自组织神经网络对这些凹陷优选排队。  相似文献   

差异扩散速度与晶体形态标型     

施光海  王长秋 《岩石矿物学杂志》1998,17(3):281-287

本文依据矿物晶体结晶时不同结晶离子对晶体结晶的作用不同,提出了差异扩散速度控制晶体形态的观点。文中论述了差异扩散速度的产生及影响因素,指出外部因素（温度、压力、粘度、酸碱度等）是通过离子的扩散速度变化来主导占位选择和形成优势面网,最终形成反映差异扩散速度的晶体形态。用差异扩散速度来解释矿物的晶体形态标型,比较全面地考虑各种外部因素的共同作用,从而避免了文中列举的片面性。此外,文中还探讨了晶体的生长方式、优势面网的产生和产生的必要条件以及相对衍射强度与优势面网的关系。  相似文献   

人工合成锰矿物实验及其产物   总被引：2，自引：1，他引：1  

单连芳  曲高生 《矿物学报》1998,18(3):281-291

通过在蒸馏水中0～10℃条件下,在含Cu、Co、Ni和有机质溶液以及不同底质的合成海水中（常温常压）合成锰矿物。结果得出,初始锰矿物是黑锰矿;控制锰矿物形成的条件是,除必要的物质来源外,起决定作用的是形成环境的酸碱度和氧化还原电位。在含硅质粘土和钙质软泥的试管中产生三层沉淀物：上部层主要是菲细粒（粒径0．5～1.5μm）黑锰矿,中间层为菲细粒黑锰矿和黑锰矿微结核（粒径5.8～43.5μm）,下部层分别为含黑锰矿微结核的硅质粘土和钙质软泥。有的实验中在硅质粘土或钙质软泥上面形成一层厚度为20～33μm黑锰矿结壳。这种结壳上表面的突起和埋藏型结核的表面相似,下表面的小突起里定向排列。  相似文献   

西藏当雄羊应乡地热田新生代火山岩特征及其成因探讨   总被引：7，自引：0，他引：7  

李家振  张有瑜 《现代地质》1992,6(1):96-109,T001

本文首次较全面系统地研究了西藏当雄羊应乡地区与地热田有关的火山岩的岩石学、矿物学、地球化学、岩石化学稀土微量元素等方面的特征,并根据这些特征及同位素年代学的方法和地层构造关系,把滨区新生代火山岩划分为4个喷发期,确定其喷发类型、规模、喷发旋回及岩相特征。通过现代岩石学的研究方法及理论分析,讨论该区火山岩的成因,并确定其岩浆并非原生岩浆,而是派生岩浆。采用了Stormer和Nicholls(1978)提出的主要元素质量平衡原理,进一步计算了派生岩浆演化的特点。通过(?)Sr/(?)"Sr的初始比值的研究,认为本区火山岩浆是来源于壳源下相当于辉长岩质成分的部分熔融结果。  相似文献   

Ocean–atmosphere Teleconnections Play a Key Role in the Interannual Variability of Seasonal Gross Primary Production in China     

Kairan YING  Jing PENG  Li DAN  Xiaogu ZHENG 《大气科学进展》2022,39(8):1329-1342

Since the 1950s, the terrestrial carbon uptake has been characterized by interannual variations, which are mainly determined by interannual variations in gross primary production (GPP). Using an ensemble of seven-member TRENDY (Trends in Net Land–Atmosphere Carbon Exchanges) simulations during 1951–2010, the relationships of the interannual variability of seasonal GPP in China with the sea surface temperature (SST) and atmospheric circulations were investigated. The GPP signals that mostly relate to the climate forcing in terms of Residual Principal Component analysis (hereafter, R-PC) were identified by separating out the significant impact from the linear trend and the GPP memory. Results showed that the seasonal GPP over China associated with the first R-PC1 (the second R-PC2) during spring to autumn show a monopole (dipole or tripole) spatial structure, with a clear seasonal evolution for their maximum centers from springtime to summertime. The dominant two GPP R-PC are significantly related to Sea Surface Temperature (SST) variability in the eastern tropical Pacific Ocean and the North Pacific Ocean during spring to autumn, implying influences from the El Ni?o–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). The identified SST and circulation factors explain 13%, 23% and 19% of the total variance for seasonal GPP in spring, summer and autumn, respectively. A clearer understanding of the relationships of China’s GPP with ocean–atmosphere teleconnections over the Pacific and Atlantic Ocean should provide scientific support for achieving carbon neutrality targets.  相似文献   

庙岛群岛北五岛生态系统净初级生产力与景观格局时空分布异质性研究     

殷丽婷  郑伟  高猛  路景钫 《海洋学报》2020,42(6):110-118

利用ArcGIS10.2、ENVI5.1、SPSS26等软件，本文基于经典CASA模型估算了2005年、2010年、2017年庙岛群岛北五岛的净初级生产力(Net Primary Productivity, NPP)，从季节、岛屿、景观类型、地形梯度等多种角度分析了NPP的时空分布异质性；进而分析了2005年、2010年、2017年北五岛的景观格局时空分布异质性；探讨了NPP与景观格局时空变化之间的关系及其原因。结果表明:庙岛群岛北五岛平均全年NPP总量为7 520.54 t/a(以碳计)，平均密度为406.07 g/(m2·a) (以碳计)；NPP分布呈明显的时空分异性；各景观类型平均面积由大到小依次为:针叶林、阔叶林、建设用地、草地、耕地；其NPP平均密度由大到小依次为:阔叶林、针叶林、耕地、草地、建设用地；各景观NPP平均密度随坡度和高差的增大先上升后出现平缓下降态势；坡向对林地NPP影响较大，半阴坡林地NPP平均密度最大；不同地形梯度的NPP年平均密度随时间推移总体呈下降态势；NPP高值出现在山林区域，低值主要在建设用地区域；由于自然地理条件、植物自身生长条件和人类活动强度等原因，NPP时空异质性分布受季节差异、景观格局时空异质性和地形因子影响显著。  相似文献   

Specific oceanographic characteristics and phytoplankton responses influencing the primary production around the Ulleung Basin area in spring     

Lee Minji  Kim Jin Ho  Kim Yun-Bae  Park Chan Hong  Shin Kyoungsoon  Baek Seung Ho 《海洋学报(英文版)》2020,39(2):107-122

The East Sea(Sea of Japan)is a marginal,semi-closed sea in the northwestern Pacific.The Ulleung Basin area,which is located near the subpolar front of the East Sea,is known to have high primary production and good fisheries in spring season.After episodic wind-driven events during the spring of 2017,horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area.In addition,growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass.Because of strong northwestern wind,phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season.The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations.In contrast,the nutrient and chlorophyll a(Chl a)concentrations and the phytoplankton biomass were quite low in all locations.Bacillariophyceae was dominated group(>75.1%for coastal,40.0%for offshore and 43.6%for island stations).In the algal bioassays,the phytoplankton production was stimulated by N availability.The in vivo Chl a values in the+N and+NP treatments were significantly higher than the values in the control and the+P treatments.Based on the field survey,the higher nutrients in coastal waters affected the growth of diatom assemblages,however,little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments.The growth of phytoplankton depended on the initial cell density.All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers,and the low level of biomass supply from the coasts resulted in low primary production.Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea.  相似文献   

The influence of pumping parameters in fluid‐driven fractures in weak porous formations          下载免费PDF全文

Ernestos Sarris  Panos Papanastasiou 《国际地质力学数值与分析法杂志》2015,39(6):635-654

In this work, we investigate the main pumping parameters that influence a fluid‐driven fracture in cohesive poroelastic and poroelastoplastic weak formations. These parameters include the fluid viscosity and the injection rate. The first parameter dominates in the mapping of the propagation regimes from toughness to viscosity, whereas the second parameter controls the storage to leak‐off dominated regime through diffusion. The fracture is driven in weak permeable porous formation by injecting an incompressible viscous fluid at the fracture inlet assuming that the fracture propagates under plane strain conditions. Fluid flow in the fracture is modeled by lubrication theory. Pore fluid movement in the porous formation is based on the Darcy law. The coupling follows the Biot theory, whereas the irreversible rock deformation is modeled with the Mohr–Coulomb yield criterion with associative flow rule. Fracture propagation criterion is based on the cohesive zone approach. Leak‐off is also considered. The investigation is performed numerically with the FEM to obtain the fracture opening, length, and propagation pressure versus time. We demonstrate that pumping parameters influence the fracture geometry and fluid pressures in weak formations through the viscous fluid flow and the diffusion process that create back stresses and large plastic zones as the fracture propagates. It is also shown that the product of the propagation velocity and fluid viscosity, µv that appears in the scaling controls the magnitude of the plastic zones and influences the net pressure and fracture geometry. These findings may explain partially the discrepancies in net pressures between field measurements and conventional model predictions for the case of weak porous formation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

南海北部4万年以来有机碳和碳酸盐含量变化及古海洋学意义   总被引：2，自引：0，他引：2  

李丽  王慧  罗布次仁  贺娟 《海洋地质与第四纪地质》2008,28(6)

南海北部陆坡的17937柱状样上部4万年来有机碳和碳酸盐的含量分布特征显示：有机碳含量总体显示出冰期高、间冰期低的特征，碳酸盐则相反。C／N元素比分布范围和二组分分析说明该站位的有机碳以海洋自生有机碳为主，全新世达80％以上。根据海洋沉积物中总有机碳含量和两类不同来源有机碳所占比例计算得出的海洋自生生物产生的有机碳含量在MIS2时期最高，说明末次冰期海洋生产力提高。冰期冬季风强化，海水混合程度加强，营养物质利用更充分以及陆源输入增多导致营养物质增加。碳酸盐含量主要受陆源物质稀释的影响，为“大西洋型”旋回。碳酸盐旋回在全新世早中期存在低碳酸钙事件，可能与该时期的强降雨冲刷所致陆源稀释作用增强、海水溶解作用增强以及海洋表层生产力的降低等综合作用相关。  相似文献   

Influence of allochthonous input on autotrophic–heterotrophic switch-over in shallow waters of a tropical estuary (Cochin Estuary), India     

Shoji D. Thottathil  K.K. Balachandran  G.V.M. Gupta  N.V. Madhu  Shanta Nair 《Estuarine, Coastal and Shelf Science》2008

Bacterial productivity (BP) and respiration (BR) were examined in relation to primary productivity (PP) for the first time in a shallow tropical ecosystem (Cochin Estuary), India. The degree of dependence of BP (6.3–199.7 μg C L⁻¹ d⁻¹) and BR (6.6–430.4 μg C L⁻¹ d⁻¹) on PP (2.1–608.0 μg C L⁻¹ d⁻¹) was found to be extremely weak. The BP/PP (0.05–8.5) and PP/BR (0.02–7.9) ratios widely varied in the estuary depending on the season and location. There was a seasonal shift in net pelagic production from autotrophy to heterotrophy due to terrestrial organic matter input through rivers which enhanced the bacterial heterotrophic activity and very high pCO₂ (106–6001 μatm) levels. The heterotrophic zones were characterized by low PP but high bacterial production and respiration leading to oxygen undersaturation and exceptionally high pCO₂. We propose that the CO₂ supersaturation caused by increased bacterial respiration (in excess of PP) was a result of bacterial degradation of allochthonous organic matter. This indicates that sources other than planktonic compartment need to be explored to understand the C-cycling in this estuary. These results are of particular relevance to tropical ecosystems in general, where the bulk of world's river discharges occur.  相似文献