辽东半岛南部寒武系与奥陶系界线     

王敏成 《国土资源》1990,(1)

笔者(1989)在辽东半岛南部复州湾和金县七顶山寒武系与奥陶系界线附近发现一层笔石,它们为:Airograptus furciferus,Staurograptus sp.,Dendrograptus sp.,并且建立了 Airograptus furciferus-Staurograptus 带,该带相当于华北的 Dictyonema flabelliforme-Staurograptus 带,相当于华南东南区的Staurograptus-Anisograptus 带,其层位相当于英国的特马豆克阶。由于该区寒武系顶部已建立了笔石带Dictyonema kelanense 带,因此,笔者将辽东半岛南部寒武系与奥陶系界线划在 Airograptus furciferus-Staurograptus 带与 Dictyonema kelanense 带之间。  相似文献   

从辽宁东、西部地质对比论郯庐断裂的平移运动     

陈荣度 《国土资源》1995,(3)

辽宁东、西部地质上诸多差异并非是原地升降运动造成的，而是二个异地岩块经郯庐断裂大规模左旋平移运动迁移到一起的结果。辽东半岛原曾与鲁西－徐淮地区处于相同的古纬度。郯庐断裂北延的主干断裂应是抚顺－敦化断裂，它在辽宁境内是地层区划的重要界线。郯庐断裂在太古宙末期即已出现，曾多次变换其平移方向，最近一次大规模左行平移活动的高峰期是在晚侏罗世晚期－早白垩世，结束于孙家湾组或泉头组堆积之前。  相似文献   

Coastal Upwelling Activity on the Pacific Shelf of the Baja California Peninsula     

Oleg Zaytsev  Rafael Cervantes-Duarte  Orzo Montante  Artemio Gallegos-Garcia 《Journal of Oceanography》2003,59(4):489-502

High primary productivity on the Pacific coast of the Baja California Peninsula is usually related to coastal upwelling activity that injects nutrients into the euphotic zone in response to prevailing longshore winds (from the northwest to north). The upwelling process has maximum intensity from April to June, with the coastal upwelling index varying from 50 to 300 m³/s per 100 m of coastline. Along the entire coast of the peninsula, the upwelling intensity changes in accordance with local wind conditions and bottom topography. Spatial variability can also be modulated by the influence of mesoscale meanders of the California Current. We have identified the seasonal and synoptic variability of upwelling signatures on the Baja California shelf, using averaged monthly and weekly sea surface temperature (SST) distributions obtained from remote sensing imagery from the Advanced Very High Resolution Radiometer in the period from 1996 to 2001. Analysis of SST distribution and direct experimental data on temperature and nutrient concentration shows that the areas with the coldest SST anomalies were closely related to the bottom slope, shelf width, and coastline orientation relating to wind direction. We also assume that the nutrient transport into the coastal lagoons may be forced by the coupling of coastal upwelling and tidal pumping of surface waters into the lagoon system. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Description of the post larva of star pipefish,halicampus punctatus (syngnathidae, gasterosteiformes) first found in the southwestern east sea, Korea     

Sung Kim  Jina Oh  Youn -Ho Lee 《Ocean Science Journal》2006,41(4):201-205

Larval specimens ofHalicampus punctatus were collected off Ulsan and Uljin in December 2002 (three specimens) and off Ulsan in December 2003 (one specimen). These specimens are characterized by the following morphological characteristics: rings, 14 + 35 = 49; subdorsal rings, 1 + 3 = 4; dorsal fin rays, 19 – 20; pectoral fin rays, 14 – 15; anal fin rays, 9; head length (HL), 5.8 – 6.7 in the standard length; snout length, 1.9 in HL; snout depth, 3.7 – 5.2 in snout length. The number of caudal fin rays 9 is less than those of the other species in the same genus 10. Wide stripe bands composed of small pigments are shown in the trunk and the tail. Melanophores are not found in the dorsal fin, the pectoral fin, and the anal fin except the caudal fin. The supraoccipital crest is on the head. The frontal ridge is on the dorsal side of front trunk. The blanched ridges on the opercular are fused with a main ridge like a tree branch. A few branched ridges that are small and narrow on the trunk and the tail are fused with the main ridges. We report these specimens as the first record in Korea and name them ‘Byeol-silgo-ki’ in Korean.  相似文献   

Limitations of the Korean conventional fisheries management regime and expanding Korean TAC system toward output control systems     

Jeong-Gon Ryu  Jongoh Nam  John M. Gates 《Marine Policy》2006

In this paper, we focus on the status and trends of the current Korean fisheries management regime. Specifically, this paper briefly introduces the Korean conventional fisheries management regime (KCFMR) and discusses its problems and limitations. In describing policy evolution, this paper finds reasons why the Korean government has chosen a TAC system, an output control approach, besides input control approaches in force for almost a century. This paper also describes the evolution of the Korean TAC system, which is carrying out a pivotal role in Korean fisheries development, and analyzes problems of the Korean TAC system. Finally, this paper gives a perspective on expanding the Korean TAC system toward Output Control Systems (OCSs) such as Individual Quotas (IQs), Individual Vessel Quotas (IVQs), Individual Transferable Traps (ITTs), Community Quotas (CQs), and Individual Transferable Quotas (ITQs).  相似文献   

鲁南近浅海沉积物样品的因子分析及其地质意义     

陈敬冉  林振宏 《中国海洋大学学报(自然科学版)》1988,(3)

本文提出河流携带入海的沉积物或沿岸剥蚀物中矿物的分布及再组合是受多种因素控制的。为了确定控制鲁南两城河至白马河沉积物样品中矿物分布及再组合的主要因素,作者对该区109个沉积物样品的重矿物资料进行了Q型和R型因子分析。研究指出,在诸多的河流中,白马河和两城河是控制该区沉积物分布的最上要的河流;矿物的化学稳定性是决定该区矿物再组合的主要因素。  相似文献   

胶东半岛金矿床控矿构造特点浅析          下载免费PDF全文

赵冬冬  黄吉友  金刚 《地质找矿论丛》2008,23(2):125-129

胶东半岛金矿床的矿体(脉)均严格受断裂构造控制,这种控矿的脆/韧性叠加构造的显著特点是多期(次)活动的叠加,经过了早期的韧性剪切、后期的脆性压扭性碎裂岩化、晚期的脆性张性断裂叠加3个阶段.脆/韧型叠加构造与按"构造相"划分的脆-韧性剪切带是不同的概念,它们是性质和演化历史完全各异的两类断裂构造.金矿往往直接产于张性断裂之中,但是在同空间中更早形成的韧性剪切带和压扭性碎裂岩则对金矿化的规模具有明显的控制作用.  相似文献   

Palaeozoic and Mesozoic tectonic evolution and palaeogeography of East Asian crustal fragments: The Korean Peninsula in context   总被引：38，自引：2，他引：38  

I. Metcalfe 《Gondwana Research》2006,9(1-2):24

East and Southeast Asia comprises a complex assembly of allochthonous continental lithospheric crustal fragments (terranes) together with volcanic arcs, and other terranes of oceanic and accretionary complex origins located at the zone of convergence between the Eurasian, Indo-Australian and Pacific Plates. The former wide separation of Asian terranes is indicated by contrasting faunas and floras developed on adjacent terranes due to their prior geographic separation, different palaeoclimates, and biogeographic isolation. The boundaries between Asian terranes are marked by major geological discontinuities (suture zones) that represent former ocean basins that once separated them. In some cases, the ocean basins have been completely destroyed, and terrane boundaries are marked by major fault zones. In other cases, remnants of the ocean basins and of subduction/accretion complexes remain and provide valuable information on the tectonic history of the terranes, the oceans that once separated them, and timings of amalgamation and accretion. The various allochthonous crustal fragments of East Asia have been brought into close juxtaposition by geological convergent plate tectonic processes. The Gondwana-derived East Asia crustal fragments successively rifted and separated from the margin of eastern Gondwana as three elongate continental slivers in the Devonian, Early Permian and Late Triassic–Late Jurassic. As these three continental slivers separated from Gondwana, three successive ocean basins, the Palaeo-Tethys,. Meso-Tethys and Ceno-Tethys, opened between these and Gondwana. Asian terranes progressively sutured to one another during the Palaeozoic to Cenozoic. South China and Indochina probably amalgamated in the Early Carboniferous but alternative scenarios with collision in the Permo–Triassic have been suggested. The Tarim terrane accreted to Eurasia in the Early Permian. The Sibumasu and Qiangtang terranes collided and sutured with Simao/Indochina/East Malaya in the Early–Middle Triassic and the West Sumatra terrane was transported westwards to a position outboard of Sibumasu during this collisional process. The Permo–Triassic also saw the progressive collision between South and North China (with possible extension of this collision being recognised in the Korean Peninsula) culminating in the Late Triassic. North China did not finally weld to Asia until the Late Jurassic. The Lhasa and West Burma terranes accreted to Eurasia in the Late Jurassic–Early Cretaceous and proto East and Southeast Asia had formed. Palaeogeographic reconstructions illustrating the evolution and assembly of Asian crustal fragments during the Phanerozoic are presented.  相似文献   

中朝板块元古宙板内地震带与盆地格局   总被引：34，自引：3，他引：34  

乔秀夫 《地学前缘》2002,9(3):141-149

地史中发生的强地震事件在地层中留下固定的记录 (图 1～ 3) ,这些记录在区域上呈带状分布 ,代表地史中的地震带。中朝板块元古宙目前可识别出两个板内地震带 (图 5 )。中元古代板内地震带 (170 0～ 12 0 0Ma)西起太行山北段 ,经燕山山脉、辽宁西部、穿越辽河平原至辽宁北部的泛河流域分布 ,即燕山—泛河地震带 ,现今呈NEE向延伸。新元古代震旦纪地震带沿吉林南部、辽东半岛、山东中部及苏皖北部现今呈NNE走向分布 ,即古郯庐地震带 (6 5 0～ 6 0 0Ma)。上述两个板内地震带是元古宙不同时期超大陆裂解的响应。中元古代与新元古代两个不同方向的地震断裂带分别控制着两个时期的盆地边界。燕山泛河地震断裂带构成中元古代海盆南界 (指现在的位置 ) ,形成向北开放的海域。古郯庐地震断裂带将中朝板块裂解为华北块体与胶辽朝块体。古郯庐地震断裂带构成震旦纪海域的边界 ,震旦纪海盆通过朝鲜半岛与当时的外海相连接 ,华北块体则为陆源剥蚀区。文内四幅古地理图 (图 6～ 9)是以地震灾变思想为指导 ,以新的地层研究、对比为基础编制的 ,侧重反映了盆地的格局及其变化。根据地震、同沉积断裂新的思路 ,可提供地质学家重新认识与解释某些沉积矿床的成因 ,它们的成矿元素均来自地球深部而非地表风化作用。文中编制  相似文献   

中朝地台东北缘地区的地震层析成像   总被引：24，自引：5，他引：24       下载免费PDF全文

卢造勋  蒋秀琴  潘科  白云  姜德录  肖立萍  刘建华  刘福田  陈辉  何建坤 《地球物理学报》2002,45(3):338-351

根据中朝地台东北缘地区 (东经 1 1 7°0 0′— 1 2 6°0 0′ ,北纬 36°0 0′— 44°0 0′) 1 980— 1 997年的 380 0 0余条P波走时数据 ,利用正交投影法重建了该区地壳和上地幔的三维速度结构 .通过分析及同人工地震测深剖面的详细对比 ,证明了成像结果的可靠性 .结果表明 :中朝地台东北缘地区地壳上地幔介质存在显著的横向不均匀性 ,直至 1 2 0km深度处依然明显 ;地壳上部的速度图像清楚地反映了不同岩石单元的分布与该区不同性质的基岩分布基本吻合 ;从上、中地壳的速度图像中发现了研究区存在海城、朝阳、义县、丹东南、唐山等几个低速异常区(即速度逆反层区 ) ,其中海城、唐山、朝阳等地区的壳内低速层已由深地震测深资料所证实 ;研究区陆地发生的几次强震均发生于壳内低速层上方的高速脆性介质内 ,而渤海发生的强震 ,此现象不明显 ,但都发生于横向介质速度显著突变的位置 ;在地壳不同深度上发现了普兰店至山海关横跨渤海的北西向低速异常带 ;地震层析二维速度图像与深地震测深资料的对比表明 ,研究区利用地震层析成像技术 ,在一定条件下可以获得与人工地震测深相似的效果  相似文献