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1.
At Admiralty Bay of central King George Island, Keller Peninsula, Ull-man Spur and Point Hennequin are main Tertiary volcanic terranes. Field investigation and isotopic datings indicate that, there occurred three periods of eruptions ( three volcanic cycles) and accompanying N-toward migration of the volcanic center on Keller Peninsula. After the second period of eruptions, the crater collapsed and a cal-dera was formed, then later eruptions were limited at the northern end of the peninsula and finally migrated to Ullman Spur. Thus Keller Peninsula is a revived caldera, and its volcanism migrated toward E with time. Point Hennequin volcanism happened more or less simultaneously with the above two areas, but has no clear relation in chemical evolution with them, frequently it belongs to another independent volcanic center.  相似文献   

2.
Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.  相似文献   

3.
山东栖霞、临朐一带是山东胃癌死亡回顾调查中居首、二位的显著高死亡区。它与栖霞复背斜和临朐坳陷中的新生代火山岩区区域地质背景相吻合。火山岩受沂沭断裂和栖霞断裂等深断裂制约。山东栖霞、临朐一带新生代火山岩为富含Cr、Ni元素的地幔源基性、超基性火山喷发、分异混染、混杂玄武岩。Cr、Ni元素已被世界卫生组织国际癌症研究中心(IARC)确认为Ⅰ级、ⅡA级致癌物,与癌病有肯定的因果关系。据此推论,栖霞、临朐的新生代火山岩中Cr、Ni元素的地球化学行为是导致栖霞、临朐成为胃癌显著高死亡区的根本原因之一。  相似文献   

4.
Changes in the fungal and bacterial biomass and community structure in litter after the volcanic eruptions of Mount Usu, northern Japan were investigated using a chronosequence approach, which is widely used for analyzing vegetation succession. The vegetation changed from bare ground(10 years after the eruptions) with little plant cover and poor soil to monotonic grassland dominated by Polygonum sachalinense with undeveloped soil(33 years) and then to deciduous broad-leaved forest dominated by Populus maximowiczii with diverse species composition and well-developed soil(100 years). At three chronosequential sites, we evaluated the compositions of phospholipid fatty acids(PLFAs), carbon(C) and nitrogen(N) contents and the isotope ratios of C(δ13C) and N(δ15N) in the litter of two dominant species, Polygonum sachalinense and Populus maximowiczii. The C/N ratio, δ13C and δ15N in the litter of these two species were higher in the forest than that in the bare ground and grassland. The PLFAs gradually increased from the bare ground to the forest, showing that microbial biomass increased with the development of the soil and/or vegetation. The fungi-to-bacteria ratio of PLFA was constant at 5.3 ± 1.4 in all three sites, suggesting that fungi were predominant. A canonical correspondence analysis suggested that the PLFA composition was related tothe successional ages and the developing soil properties(P 0.05, ANOSIM). The chronosequential analysis effectively detected the successional changes in both microbial and plant communities.  相似文献   

5.
1 INTRODUCTIONA large-scale volcanic eruption can injectenormous amount of ash and dust into the atmos-phere, leading to local and short cooling due toshielding incoming radiation. During the past 2 to 3decades, accumulated evidence indicated thatlarge-scale volcano eruptions or series of volcanicactivity appears to coincide with climatologicaltransitions. For example, Robock (1979) indicatedthat volcanic eruptions played a role in forcing "Lit-tle Ice Age". Well-dated high-resolution co…  相似文献   

6.
The Dayizishan scoria cone and Jinlongdingzi scoria cone in the Longgang volcanic swarm, northeastern China are comprised of basaltic fallout tephra that derived from sub - Plinian eruptions. The airborn tephra formed a scoria cone and tephra sheets in geomorphological character. The fallout tephra deposits consist of basaltic scoria, bomb, ultramafic xenolith and lithic fragments. The tephra deposits in the tephra sheets developed plane parallel bedding and graded bedding. The size parameters of tephra changed with distance away from source and the lapse of time regularly.The Dalongwan tuff ring and Longquanlongwan tuff ring in Longgang volcanic swarm are comprised of base surge deposits, formed by phreatomagmatic explosions. The base surge deposits are composed of basaltic lapilli, pisolites and tuff.The sedimentary structure, for instance, dunelike structure, chute and pool structure, U - shaped channel and cross bedding, massive beds and sandwave beds etc. are recognized.  相似文献   

7.
雁荡山破火山口构造以其独特的火山地貌形态,完美的环状断裂和环状圈层分布的岩相,环形展市的航磁异常和地球化学异常,显示出一个地质─地球物理、地球化学、岩相─构造配置较完整的典型破火山口模式,依壳、幔二元混合模拟计算.火山岩和侵入岩源区物质组成为UC56.2DM43.8和UC56.4DM43.6,两者来自相似源区.源区处于地壳下部。  相似文献   

8.
中国近5000a来地质灾害群发期中岩石围异常事件存在着同步性、叠加性、相关性。灾害群发期与太阳活动等宇宙因素、中国不同地区环境演变──冰川进退、黄土沉积、沙漠化演化、海平面变化,降水变迁等对比分析,揭示出地质灾害群发的重要环境背景──温暖潮湿的气候条件;并且在宇宙变化→构造活动→气候变化→地质灾害群发之间存在着链锁性效应。  相似文献   

9.
Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr~(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E).  相似文献   

10.
With the rapid development of space technology, earth observation technology and sky observatory technolo-gy, they have played a more and more important part in monitoring and predicting of earthquakes and volcanoes in the terres-trial land. In recent years, the related agencies have done the experiments and researches on monitoring and predicting ofearthquakes and volcanoes in the forewarning period by means of many approaches, such as satellite thermal infrared re-mote sensing (TIRS), Global Positioning System (GPS), differential interferometric synthesis aperture radar (D-INSAR),astronomical time-latitude residual anomaly, and Geographic Information Systems (GIS), etc. A quite large number of re-search foundation has been built in the fundamental theories and application methods. The experiments and researcheshave shown that these technology is efficient methods for high frequency crust movement. If the existed separate scientificforces and results are possibly assembled together to form a more complete integration monitoring system with the combina-tion of space, sky observation, ground, deep geology and macro anomaly, it will come into a new stage of monitoring andpredicting of earthquakes and volcanic eruptions.  相似文献   

11.
1 INTRODUCTION Helium is a trace element in natural gas and the lightest element of all rare gases. It is formed during natural nuclear processes and it is chemi- cally stable. Because of its strong diffusibility and permeability, it is used as a very sen…  相似文献   

12.
西湖凹陷天台斜坡区火成岩发育尤为丰富,其发育与分布对盆内储层改造、构造演化都有着重要影响。依据区内地震特征和构造环境,划分出中心式、裂隙式2种喷发类型;采用振幅-方差体地震属性分级-拾取-融合技术,系统刻画区内火成岩的三维时空展布以及火山喷发时期,发现区内火成岩具有始新世至中新世多期间歇性发育特征,且火山机构富集于天台斜坡西南部;在区内建立了中心式和裂隙式2种喷发模式,认为这些模式的建立对于正确预测火成岩的分布具有重要意义;最后对火成岩的成因机制进行了解析与探讨,发现区内火山活动与板块构造运动相互影响、火山的时空展布与断裂也具有一定的配置关系,认为裂隙式喷发可能会形成优势的油气运移通道,中心式喷发则有利于形成良好的储集空间。基于此,我们将更容易找到区内有效的火成岩储层,对油气勘探具有重要的指示作用。   相似文献   

13.
盆地深部火山岩储层地震受能量屏蔽影响反射杂乱,使得火山岩油气藏的勘探非常困难。针对深部火山岩储层多期叠置的复杂内幕结构,研究了最优偏移距、激发周期窗口的时频电磁采集技术和时频电磁井震联合建模反演及电性节律变化火山岩期次解释技术,有效提高了该方法的深层分辨率和对深层目标的识别能力。在渤海湾盆地LD地区的研究应用效果明显,结果揭示红星构造带沙三段火山岩喷发自下而上表现出"弱-强-强-弱-弱"的"两强三弱"的特征,发育两个火山岩喷发机构,共同控制了5个期次的火山岩储层相带分布;桃园构造带沙三段各期次火山岩喷发强度明显减弱,仅发育一个火山岩喷发机构,除期次3火山岩储层相带分布范围相对较大外,其他期次火山岩主要局限分布于火山口附近,以爆发相为主,规模明显减小。后续钻探结果证实时频电磁揭示的火山岩储层分布正确,并为该区油气大发现提供了有力支撑,为探测类似的复杂目标提供了成功范例与技术方法。   相似文献   

14.
The origin and migration of natural gas and the accumulation of gas hydrates within the Pearl River Mouth Basin of the northern South China Sea are poorly understood. Based on high-resolution 2D/3D seismic data, three environments of focused fluid flow: gas chimneys, mud diapirs and active faults have been identified. Widespread gas chimneys that act as important conduits for fluid flow are located below bottom simulating reflections and above basal uplifts. The occurrence and evolution of gas chimneys can be divided into a violent eruptive stage and a quiet seepage stage. For most gas chimneys, the strong eruptions are deduced to have happened during the Dongsha Movement in the latest Miocene, which are observed below Pliocene strata and few active faults develop above the top of the Miocene. The formation pressures of the Baiyun Sag currently are considered to be normal, based on these terms: 1) Borehole pressure tests with pressure coefficients of 1.043–1.047; 2) The distribution of gas chimneys is limited to strata older than the Pliocene; 3) Disseminated methane hydrates, rather than fractured hydrates, are found in the hydrate samples; 4) The gas hydrate is mainly charged with biogenic gas rather than thermogenic gas based on the chemical tests from gas hydrates cores. However, periods of quiet focused fluid flow also enable the establishment of good conduits for the migration of abundant biogenic gas and lesser volumes of thermogenic gas. A geological model governing fluid flow has been proposed to interpret the release of overpressure, the migration of fluids and the formation of gas hydrates, in an integrated manner. This model suggests that gas chimneys positioned above basal uplifts were caused by the Dongsha Movement at about 5.5 Ma. Biogenic gas occupies the strata above the base of the middle Miocene and migrates slowly into the gas chimney columns. Some of the biogenic gas and small volumes of thermogenic gas eventually contribute to the formation of the gas hydrates.  相似文献   

15.
王家庄、碑楼铜矿床位于邹平火山岩盆地内,区内为山东重要的铜矿产地.在收集以往地质工作资料的基础上,详细分析了王家庄铜矿床与碑楼铜矿床的地质特征,总结了赋矿岩石、围岩、矿体规模、形态、产状等特征,分析了矿石中金属矿物与矿石类型;对王家庄与碑楼铜矿的成矿期次与成矿条件进行了探讨,研究发现,邹平火山岩主要经历了3次喷发与侵入...  相似文献   

16.
The Changling gas field is occurs in tight sandstone reservoirs of the Lower Cretaceous Denglouku Formation in the Changling fault depression , southern Songliao Basin , China, which constitutes a new gas-pro-ducing area in the depression .Using information on the source-reservoir-cap rock assemblage of the Denglouku Formation, fault activity, and single well burial history of well CS 1, together with data on reservoir fluid inclu-sion and laser Raman spectroscopy , we described the formation of the Changling gas field and determine that this fault depression did not possess suitable conditions for hydrocarbon generation .Coal-derived methane gen-erated from underlying hydrocarbon source rock accumulated in the Lower Cretaceous Yingcheng Formation .At the end of the Late Cretaceous Qingshankou Stage , underwater volcanic eruptions occurred in the northern part of the Changling gas field near Qian'an, resulting in the reactivation of deep faults .Mantle-sourced inorganic CO2 migrated along faults to hydrocarbon gas reservoirs in volcanic rocks of the Yingcheng Formation ;Mean-while, displaced methane ( hydrocarbon gas ) migrated upward to sand reservoirs of the Denglouku Formation . The methane accumulated and formed secondary gas reservoirs ,Therefore fault activity was the main factor con-trolling the generation of gas reservoirs in the Denglouku Formation .The main accumulation period of the Yingcheng hydrocarbon gas reservoirs was 82 Ma.Whereas gas reservoir formation in the overlying Denglongku Formation was 79 Ma, slightly later than the time of formation of the Yingcheng gas reservoir in CS 1 well area. At 79 Ma, the burial depth of the Denglouku Formation was 1800-2000 m, the diagenesis is relatively weak and the physical properties of the reservoir are relatively favorable for accumulation .This period is not only at gas generation peak time of three sets of source rock but also at the reactivation of deep faults during the forma -tion of fault-bound depressions , thereby providing favorable conditions for the migration and accumulation of methane .  相似文献   

17.
Deccan volcanic sequences( DVS) in the central Deccan volcanic province( CDVP) are designated as Sahyadri Group having ~ 500 m thick lava pile associated with multiple sedimentary beds at different stratigraphic levels. In the eastern part of CDVP between the latitude 19 °55 '--20 °25 ' N and the longitudes 78 °15 '--78 °30 ' E,palynological investigation of the intertrappean sedimentary beds at five stratigraphic levels was carried out. The study was basically aimed for tracking the floral and environmental changes across the Deccan transition. The resulting finds indicate that the intertrappean sediments at the lowest stratigraphic level between the earliest lava flows are characterized by presence of marker Maastrichtian palynomorphs- Gabonisporis vigourouxii,Aquilapollenites bengalensis,Azolla cretacea and Farabeipollis associated with triporate and tricolpate pollen grains,phytoliths of Oryzeae of Poaceae family and peridinoid dinoflagellate cysts. The increasing volcanism deteriorated the existing flora as evident by absence of pollen-spores and presence of only structured biodegraded organic matter,fungal spores,acritarchs and algal( Botryococcus) remains in the sediments of higher-up in the sequence. For chronostratigraphic constraints on the lava flows magnetic polarity of the flows bracketing the intertrappean beds was investigated. The results indicated presence of N-R-N-R magnetic polarity in the basal lava pile that are interpreted as representing the magnetochron C30 N to C28 R( Maastrichtian-Paleogene). The floral change begins with the onset of volcanism in the chron C30 N and floral deterioration is observed in C29 N with increasing volcanism and it is only in the chron C28 R( Danian) that some evidence of recovery of flora is recorded. The current study shows that in eastern part of CDVP the post Cretaceous-Paleogene boundary eruptions represent the main phase of eruptions that triggered deterioration of the flora.  相似文献   

18.
桑托斯盆地盐下碳酸盐储层中火成岩分布广泛,以盆地C区块为解剖区,通过对区内火成岩岩石学、年代学以及CO2气体同位素测试分析等,明确了区内火成岩发育特征,剖析了其对油气成藏的影响。C区块至少经历了阿普特期和圣通-坎潘期2期岩浆活动,其中阿普特期岩浆以喷发岩为主,经历了多次喷发,并伴有多次侵入;圣通-坎潘期岩浆规模较小,侵入比较随机。阿普特期岩浆多次喷发改造古地形,形成局部凸起,促成并控制了Itapema组介壳灰岩的沉积发育,形成了巨厚的火山岩-介壳灰岩复合体,不仅造成了局部构造反转和圈闭高点迁移,而且也促成了Barra Velha组优质微生物灰岩的发育。区块北翼属早期古隆,Barra Velha组也发育一定规模微生物灰岩滩体。圣通-坎潘期及之后岩浆活动伴生的CO2大规模侵入,对烃类流体进行萃取和抽提改造,形成含凝析油的CO2气藏。   相似文献   

19.
在群舞创作中,舞蹈构图就是舞蹈演员与整个舞台空间的静止画面,"静止"是舞蹈构图的表现形式,"流动"是舞蹈调度的表现形式,作为舞蹈构图与构图的必要连接,在营造舞蹈情境和增强形式美上起到了补充作用。舞蹈调度是变换舞蹈构图的一种过程,舞蹈构图是调度过程的某一个停顿和结果。二者相辅相成,不断进行连接和变化,为表现舞蹈作品的主题,交代环境情节和塑造舞蹈形象而发挥其特有的作用。  相似文献   

20.
电影不仅是作为一种艺术品,同时也是作为一种商品存在,而电影片名就好比是电影的一件外衣,因此,确切地翻译电影片名非常重要。电影片名的翻译技巧有很多,同时影响电影片名的翻译的因素也有很多。因此,在翻译电影片名时要从各方面因素考虑,从而选择恰当的翻译技巧,使得译名不仅能够从意义上忠实于源名,涵盖电影的内容,同时在形式上做到简练并具有吸引力。  相似文献   

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