用波函数展开法求解界面圆孔的SH波散射问题

研究了ＳＨ波绕界面圆孔散射的波函数展开理论。由入射,反射和透射波组成的自由波场与孔的散射场叠加成总波场。将定义于两个半平面的散射场按一定方式延拓到全平面。通过Ｈａｎｋｅｌ－Ｆｏｕｒｉｅｒ型积分来满足界面与孔缘处的边界条件,得到了确定特定系数的封闭代数方程组。给出了具体算例,计算了孔缘处的动应力系数分布。     

Research, Extension and Industry – Working Together Can Achieve Results

Over recent decades, research has been directed to assessing the impacts of land uses on valuable natural assets, such as the Great Barrier Reef. Land managers in adjacent areas are expected to adopt practices to minimize any adverse affects on downstream environments. Conversely, researchers are being pressed to provide answers to the problems. In response, researchers and environmental managers are bombarding land managers with information regarding the potential environmental implications of their practices. Is this an effective mode to achieve on-ground change?

Collaboration between all groups – research, industry and extension – may be more effective in developing and implementing practical solutions to these more complex issues. A change from the research and extension models currently used may be needed to achieve positive resource management outcomes.

Research, development and extension initiatives underway in the Australian sugar industry to improve farm practice and reduce the potential for adverse impacts on downstream environments are discussed. Case studies provide some insights into how science and extension skills work best together and how an industry group can respond to a community concern.     

秦岭造山带及相邻地块元古代基性岩墙群研究综述及相关问题探讨

基性岩墙群是重建古陆块聚合、伸展乃至裂解的关键标志之一。通过对秦岭造山带及相邻的华北地块、扬子地块元古代基性岩墙群的时空对比综 合分析表明,华北地块区发育2300Ma±和1700～1200Ma的两期基性岩墙群,分别代表了新太 古代和古元古代华北古陆块的聚合、伸展过程;扬子地块区发育800～620Ma的基性岩墙群, 反映了新元古代扬子古陆块的聚合、伸展过程。认为前震旦纪华北地块和扬子地块可能是独 立古陆块或不同古陆块的组成部分。晋宁造山作用(1100～850Ma)和澄江伸展、裂解作用(800Ma±)是可与新元古代Rodinia超大陆聚合、裂解过程进行对比、研究的重要时期。     

藏南聂拉木地区上三叠统与侏罗系中伸展不整合以及各组地层的厘定

晚三叠世及侏罗纪是特提斯大洋形成和扩张的时期。藏南聂拉木地区的相应地层中普遍存在裂陷盆地沉积及众多的伸展不整合。根据这些不整合面之上的“超越下伏地层不正常的化石混积事件”,判断早侏罗世赫唐早期和中侏罗世巴通期裂陷幅度分别为大于 1 60 0 m和大于80 0 m。作者根据这些不整合面以及遵循地层命名的“优先法则”,对各个组的地层划分与名称进行了厘定。     

秦岭构造带的东延兼述其高压变质带的形成深度与机制

在介绍郯庐断裂东西两侧ＥＷ向构造基本特征的同时,从将秦岭带理解为高级协和函数和边界条件差异及构造复合等方面具体探讨了下述问题：为什么秦岭东延后构造形迹显得宽散零落？ＮＥ向的苏鲁变质岩构造带何以也成为秦岭构造带的成份？重塑了“老淮阳弧构造”,指出在郯庐断裂东侧,古老的秦岭带发生北移,中新生代秦岭带又在原水的纬度上产生,其构造形迹北抵海州湾两侧,南达杭州湾附近。还探讨了该区高压变质带的形成深度和动力学     

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA.

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA     

SYNCONVERGENT, DUCTILE N-DIRECTED SHEARING ON THE WESTERN MARGIN OF THE NANGA PARBAT SYNTAXIS, N. PAKISTAN

SYNCONVERGENT, DUCTILE N-DIRECTED SHEARING ON THE WESTERN MARGIN OF THE NANGA PARBAT SYNTAXIS, N. PAKISTAN1　BurgJ P ,ChaudryMN ,GhazanfarM ,etal.StructuralevidenceforbackslidingoftheKohistanarcinthecollisionalsystemofnorthwestPakistan[J] .Geology 1996 ,2 4 ( 8) ,739～ 74 2 . 2　ChamberlainCP ,ZeitlerPK ,EricksonE .ConstraintsonthetectonicevolutionofthenorthwesternHimalayafromgeochronologicandpetrologicstudiesofBabusarPass,Pakistan[J] .Journa…     

庐枞早白垩世火山岩的地球化学特征及其源区意义

从中生代到新生代,华北东部岩石圈地幔发生了减薄以及地球化学性质置换, 而扬子地块东部中生代岩石圈地幔也表现出类似的过程,对中生代火山岩的地球化学研究有助于了解这一变化过程以及发生置换时的时空关系。庐枞火山岩出露于扬子地块东部,为一套包括粗玄岩–玄武粗安岩–粗面岩的富碱橄榄安粗岩系。研究了双庙组基性火山岩,这些岩石富集Rb,K,Sr,Th和轻稀土元素,亏损高场强元素。(87Sr/86Sr)i = 0.7060~0.7063,εNd(t )=-3.9~-6.2,(206Pb/204Pb)i=17.788~18.125,(207Pb/204Pb)i= 15.511~15.546,(208Pb/204Pb)i =37.735~38.184。在喷出地表过程中,火山岩没有受到明显的地壳物质混染,因此元素和同位素组成反映了地幔源区的地球化学特征。 其地幔源区具有同位素富集特征,表明火山岩源区曾受到地壳物质的影响,是富集地幔部分熔融的产物,并经历明显的结晶分异作用。庐枞火山岩的岩浆成分和源区特征反映该地区在晚中生代岩石圈地幔的伸展和软流圈地幔上涌的演化过程。     

Post-collisional extension of the East Greenland Caledonides: a geophysical perspective

Crustal extension during and following continental collision is well documented in the Arctic Caledonian fold belt. However, models for the post-collisional extension of the Caledonides are mainly based on geoscientific data from Scandinavia. For a more complete understanding of the evolution of the Caledonides, knowledge of the crustal structure of East Greenland is vital. Seismic and gravity studies have revealed a pronounced Moho topography and a west-dipping lower crustal reflector beneath the fjord region of East Greenland. These deep crustal structures are related to Late Caledonian extensional structures at the surface. The observations can be satisfactorily explained by applying simple shear or eduction models proposed for upper crustal extension in Scandinavia to the complementing lower crustal structures in East Greenland. However, exhumation of the Caledonian Northeast Greenland eclogite province cannot be accomplished by these models. Instead, a synthesis of geoscientific data has shown marked differences in the crustal structure of East Greenland north and south of about 76°N, indicating a different crustal evolution of the northern and southern parts of the East Greenland Caledonides.     

地图质量可拓综合评价模型

可拓学是解决矛盾问题的新兴交叉学科,理论支柱是物元理论和可拓集合。它以物元为基本元,通过物元变换来建立物元模型,化矛盾问题为相容问题。基于可拓论探讨了地图质量的可拓综合评价新模型,即通过构造各评定等级的经典域和全体等级的节域物元矩阵,计算待评物元与各评定等级之间的关联度,判定对各评定等级的符合程度而作出综合评定。文中给出了具体评价流程,并应用于实际地图的质量综合评价,结果同其它方法进行了对比,取得了较好的结果。