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1.
焦家断裂带是胶西北地区三大著名的金成矿带之一,一般认为焦家断裂带为龙（口）莱（州）断裂带南段的高家庄子紫罗姬家段。根据近几年的研究成果,认为焦家断裂带在紫罗姬家以南,沿195＆#176;～200＆#176;方位延伸至紫罗綦家与黄家之间分为3支：第一分支沿紫罗綦家—赵官庄—前单家—张家埠至曹家埠村北;第二分支（主断裂带）沿紫罗綦家村东南—大尹家—西尹—西罗台村南至曹家埠村南;第三分支自紫罗綦家与黄家村之间向南延伸至史家村西之后,再向南去向不明,推测逐渐尖灭的可能性较大。 相似文献
2.
阿尔金断裂东段断层滑动方式的研究 总被引：10，自引：2，他引：8
采用宏观、微观相结合的方法 ,对阿尔金断裂东段断层滑动方式进行研究 ,结果表明 :(1)阿尔金断裂东段由多条羽列状次级断层所组成 ,相邻两次级断层间的夹角 :A段 15,B段 12,C段 5;(2 )断层物质具明显的组构现象 ,眼球状流动构造 ,较小的剪切破裂角等是阿尔金断裂东段断层蠕动的结果 ;(3)断层泥石英碎砾 SEM特征显示阿尔金断裂东段 Q3以来主要是蠕滑 ,但不同区段稍有不同。综上所述 ,阿尔金断裂东段断层活动主要是蠕滑 ,愈向东其蠕滑程度愈高。 相似文献
3.
The reactivation of faults induced by natural/human induced fluid pressure increases is a major concern to explain subsurface fluid migration and to estimate the risk of losing the integrity of reservoir/seal systems. This study focusses on paleo-fluid migration in a strike slip fault with >100 m long, affecting a Toarcian shale (Causses Basin, France). A high calcite concentration is observed in a 5 cm thick zone at the boundary between the fault core and damage zone. Cumulated displacements in this zone are of millimeter-to-centimeter-scale offsets and different dilatant deformation textures are observed. The zone is affected by thin slip planes containing gouge. Cathodo-luminescence observations indicate that two phases of vein formation occurred. The first phase coincides with the fluid migration along this centimeter thick dilatant zone. The second one is associated to re-shear along the millimeter thick slip planes that results in more localized mineralization, but also in a better hydrologic connection through the shale formation. These results show that in shales fluids may migrate off a slipping surface in centimeter scale dilatant volumes, at first controlled by the intact shale anisotropy related to bedding and then favored by brecciating, structures re-orientation and strengthening processes induced by calcite sealing effects. 相似文献
4.
A study of pollution transport from the surface through 100 m of Upper Cretaceous limestone into the underlying Postojnska Jama found the highest pollution in three seeps. Flushing of nitrates and chlorides continued for 11 years after source removal, while sulphates and phosphates continued even longer. A tracing test from the surface with uranin dye and added water in the dry season caused a rapid reaction in the most conductive seep. Expulsion of the remaining dye (forced by precipitation) occurred with a delay of up to 3 months. Dye injected during the wet season was transported only by precipitation and appeared in the cave within 21–43 h. The best connection between the surface and the cave exists along a subvertical tectonically fissured zone to a broken zone (80–90/90). Percolation through a less permeable trickle is limited to the tectonically broken zone 70/90. Percolation through dripping follows the subvertical fissured to broken zones and the dip direction of bedding planes. 相似文献
5.
滇藏铁路沿线滇藏交界段劈理化带成因探讨及工程效应分析 总被引：3，自引：0，他引：3
滇藏铁路沿线滇藏交界段劈理化带是新近发现的与高山峡谷区河流岸坡密切相关的介于劈理与节理之间的密集破裂构造型式。我们对劈理化带进行了较全面的调查、测绘、统计和分析, 由此得出, 劈理化带呈带状断续分布, 规模与河流岸坡规模有关, 在金沙江和澜沧江岸坡地带规模巨大, 并与微地貌关系密切。另外, “劈理”具有倾角陡、不均匀等特点, “劈理”走向往往与河流方向一致。劈理化带是在内、外动力相互作用下形成, 内动力作用可以形成劈理化带, 在内动力作用的基础上, 河谷地带的外动力作用也可以形成劈理化带, 内、外动力对劈理化带均有后期改造作用。拟建的滇藏铁路将通过许多劈理化带, 那里将来可能产生铁路地基大变形、隧道和桥梁大变形、隧道冒顶、隧道渗漏和发生滑坡、崩塌、泥石流灾害。因此, 在将来铁路等工程建设和运营中要采取针对性防治措施。 相似文献
6.
《Journal of Structural Geology》2001,23(6-7):1031-1042
The Eastern Highlands shear zone in Cape Breton Island is a crustal scale thrust. It is characterized by an amphibolite-facies deformation zone ∼5 km wide formed deep in the crust that is overprinted by a greenschist-facies mylonite zone ∼1 km wide that formed at a more shallow level. Hornblende 40Ar/39Ar plateau ages on the hanging wall decrease towards the centre of the shear zone. In the older zone (over 7.8 km from the centre), the ages are between ∼565 and ∼545 Ma; in the younger zone (within 4.5 km of the centre), they are between ∼425 and ∼415 Ma; and in the transitional zone in between, they decrease abruptly from ∼545 to ∼425 Ma. Pressures of crystallization of plutons in the hanging wall, based on the Al-in-hornblende barometer and corresponding to depth of emplacement, increase towards the centre of the shear zone and indicate a differential uplift of up to ∼28 km associated with movement along the shear zone. The age pattern is interpreted to have resulted from the differential uplift. The pressure data show that rocks exposed in the younger zone were buried deep in the crust and did not cool through the hornblende Ar blocking temperature (∼500°C) until differential uplift occurred. The 40Ar/39Ar ages in the zone (∼425–415 Ma) thus date shear zone movement or the last stage of it. In contrast, rocks in the older zone were more shallowly buried before differential uplift and cooled through the blocking temperature soon after the emplacement of ∼565–555 Ma plutons in the area, long before shear zone movement. The transitional zone corresponds to the Ar partial retention zone before differential uplift. The 40Ar/39Ar age pattern thus reflects a Neoproterozoic to Silurian cooling profile that was exposed as a result of differential uplift related to movement along the shear zone. A similar K–Ar age pattern has been reported for the Alpine fault in New Zealand. It is suggested that such isotopic age patterns can be used to help constrain the ages, kinematics, displacements and depth of penetration of shear zones. 相似文献
7.
New geological observations, recent published data and U–Pb SHRIMP zircon dating from the Karakoram Mountains along the Nubra and Shyok Rivers reveal that the initial subduction of the Tethyan oceanic lithosphere took place ~ 110 Ma beneath the Paleozoic–Mesozoic platform of the southern edge of the Asian Plate. This has produced the I-type plutons within the Karakoram Batholith Complex, well before the juxtaposition of the Asian Plate along the Karakoram Shear Zone. Within this shear zone, U–Pb zircon crystallisation ages of ~ 75 Ma from mylonitised granitoids and 68 Ma from undeformed Tirit granodiorite constrain the timing of suturing of the Karakoram terrain with the Trans-Himalaya between 75 and 68 Ma. Post-shearing leucogranite was episodically generated within frontal migmatised Karakoram Metamorphic Belt and emplaced between 20 and 13 Ma within the shear zone. Presence of a low resistivity zone as a possible indication of mid-crustal partial molten crust underneath the Higher Himalaya–Ladakh–Karakoram terrains manifests the impingement of the Indian Plate along the Main Himalayan Thrust at depth.
Physical continuity of the Baltoro granite belt into the Karakoram Batholith is established as well as the continuity of the Shyok suture as the Shiquanhe Suture Zone in western Tibet through the Chushul–Dungti sector. The Karakoram Shear Zone, therefore, displays a complex geological history of movements since ~ 75 Ma and plays a very significant role in the overall India–Asia convergence, rather than merely being a strike-slip fault for eastward extrusion of a segment of Asia in Tibet. 相似文献
8.
Recent detailed mapping along the Motagua fault zone and reconnaissance along the Chixoy—Polochic and Jocotán—Chamelecón fault zones provide new information regarding the nature of Quaternary deformation along the Caribbean—North American plate boundary in Central America.The southern boundary of the Motagua fault zone is defined by a major active left-slip fault that ruptured during the February 4, 1976 Guatemala earthquake. The recurrent nature of slip along the fault is dramatically demonstrated where stream terraces of the Río El Tambor show progressive left-slip and vertical (up-to-the-north) slip. Left-slip increases from 23.7 m (youngest mappable terrace) to 58.3 m (oldest mappable terrace) and vertical slip increases from 0.6 m to 2.5 m. The oldest mappable terrace crossed by the fault appears to be younger than 40,000 years and older than 10,000 years.Reconnaissance along the Chixoy—Polochic fault zone between Chiantla and Lago de Izabal has located the traces of a previously unmapped major active left-slip fault. Geomorphic features along this fault are similar to those observed along the active trace of the Motagua fault zone. Consistent and significant features suggestive of left-slip have so far not been observed along the Guatemala section of the Jocotán—Chamelecón fault zone.In Central America, the active Caribbean—North American plate boundary is comprised of the Motagua, Chixoy—Polochic, and probably the Jocotán—Chamelecón fault zones, with each accommodating part of the slip produced at the mid-Cayman spreading center. Similarities in geomorphic expression, apparent amount of left-slip, and frequency and magnitude of historical and instrumentally recorded earthquakes between the active traces of the Motagua and Chixoy—Polochic fault zones suggest a comparable degree of activity during Quaternary time; the sense and amount of Quaternary slip on the Jocotán—Chamelecón fault zone remain uncertain, although it appears to be an active earthquake source. Uplift of major mountain ranges on the north side of each fault zone reflects the small but consistent up-to-the-north vertical component (up to 5% of the lateral component) of slip along the plate boundary. Preliminary findings, based on offset stream terraces, indicate a late Quaternary slip rate along the Caribbean—North American plate boundary of between 0.45 and 1.8 cm/yr. Age dating of offset Quaternary terraces in Guatemala will allow refinement of this rate. 相似文献
9.
Metamorphism and deformation at different structural levels in a strike-slip fault zone, Ross Lake fault, North Cascades, USA 总被引：1，自引：0，他引：1
S. M. GORDON D. L. WHITNEY R. B. MILLER N. McLEAN N. C. A. SEATON 《Journal of Metamorphic Geology》2010,28(2):117-136
Continental crust is displaced in strike-slip fault zones through lateral and vertical movement that together drive burial and exhumation. Pressure – temperature–deformation ( P–T–d ) histories of orogenic crust exhumed in transcurrent zones record the mechanisms and conditions of these processes. The Skagit Gneiss Complex, a migmatitic unit of the North Cascades, Washington (USA), was metamorphosed at depths of ∼25–30 km in a continental arc under contraction, and is bounded on its eastern side by the long-lived transcurrent Ross Lake fault zone (RLFZ). The P–T–d conditions recorded by rocks on either side of the RLFZ vary along the length of the fault zone, but most typically the fault separates high-grade gneiss and plutons from lower-grade rocks. The Ruby Mt–Elijah Ridge area at the eastern margin of the Skagit Gneiss exposes tectonic contacts between gneiss and overlying rocks; the latter rocks, including slivers of Methow basin deposits, are metamorphosed and record higher-grade metamorphism than in correlative rocks along strike along the RLFZ. In this area, the Skagit Gneiss and overlying units all yield maximum P–T conditions of 8–10 kbar at >650 °C, indicating that slices of basin rocks were buried to similar mid-crustal depths as the gneiss. After exhumation of fault zone rocks to <15 km depth, intrusion of granitoid plutons drove contact metamorphism, resulting in texturally late andalusite–cordierite in garnet schist. In the Elijah Ridge area of the RLFZ, an overlapping step-over or series of step-overs that evolved through time may have facilitated burial and exhumation of a deep slice of the Methow basin, indicating that strike-slip faults can have major vertical displacement (tens of kilometres) that is significant during the crustal thickening and exhumation stages of orogeny. 相似文献
10.
东准噶尔蒙西斑岩铜钼矿床脉体特征及其形成机制 总被引：5，自引：1，他引：4
蒙西斑岩铜钼矿床位于东准噶尔伊吾县琼河坝花岗岩北侧,以发育细脉、网脉状矿化为特征。脉体类型多样,包括石英脉、石英硫化物脉和硫化物脉等。根据脉体力学成因机制,其又可划分为水压破裂充填脉和构造破裂充填脉。构造破裂充填脉体按破裂形成的位错特征有正断与逆断两种。地表石英脉产状陡立,明显受断裂控制。脉体体积分数统计结果显示流体富集区呈向北缓倾的带状分布于深100～400m范围内,并与矿化富集带有较好的对应关系。脉体富集带内,脉体以共轭形式存在,一组为倾角较小的逆断破裂充填脉,另一组为倾角较大的正断破裂充填脉,他们可能为缓倾逆冲剪切带的次级破裂与充填脉,即富矿带内脉体是沿矿区低角度逆冲断裂次级破裂面充填的。矿区地表及深部(400m以下)脉体以陡立为主,矿化较弱。矿区流体的运移具先沿水压直立破裂往上运移,进入剪切带后沿剪切带次级破裂侧向和向上运移,并在剪切带中富集成矿。低温矿物组合脉体穿切高温矿物组合脉体的特征说明脉体形成过程矿区处于隆升构造环境,这对斑岩铜矿成矿有利。 相似文献
11.
The Garm polygon is confined to the junction between Tien-Shan and the Peter the Great fault zone separating the Pamirs and Tien-Shan. It is just in the zone of contact between the fault zone itself and Tien-Shan (the spurs of the Gissar ridge) that a submeridional overthrust of the fault zone on the Gissar block is revealed along the surface inclined to the horizontal by an angle of 40°, the velocity of the overthrust being approximately 20–25 mm/yr. Recently the area of the polygon has been increased. Investigations over the expanded polygon permit the preliminary conclusion that alongside the overthrust mentioned above there is a block in the fault zone approaching southwesterly along the contact with the Gissar block. Attempts are made to enlarge the deformational network so as to cover the fault zone completely. 相似文献
12.
东昆仑活动断裂带强震地表破裂分段特征 总被引：1，自引：0，他引：1
东昆仑活动断裂带是青藏高原内部一条长度达到1000km以上的活动断裂带。在近100年期间,沿该断裂带曾发生过4次MS7.0以上地震。最新一次强震是2001年昆仑山口MS8.1地震。本文综合前人资料,通过东昆仑活动断裂带的几何展布、活动速率、历史强震及古地震地表破裂带展布,讨论了该断裂带的强震破裂分段特征、强震破裂端点障碍体的稳定性,强调了从断裂带演化过程认识断裂带的几何展布与现今强震地表破裂分段的异同,并讨论了该断裂带未来的强震破裂危险地段。 相似文献
13.
Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert,USA 总被引：1，自引：0，他引：1
Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams
in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable
isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek
Washes indicate that infiltration of streamflow occurs to depths below the root zone, and presumably to the water table, along
much of Oro Grande Wash and near the mountain front along Sheep Creek Wash. Differences in infiltration at sites along each
wash are the result of hydrologic variables such as proximity to the mountain front, quantity of streamflow, and texture of
the subsurface deposits. Differences in infiltration between the washes are the result of large-scale geomorphic processes.
For example, Oro Grande wash is incised into the Victorville fan and infiltration has occurred at approximately the same location
over recent geologic time. In contrast, Sheep Creek Wash overlies an active alluvial fan and the stream channel can move across
the fan surface through time. Infiltration does not occur to depths below the root zone at control sites outside of the washes.
Electronic Publication 相似文献
14.
T. K. Biswal V. Thirukumaran Kamleshwar Ratre Krishanu Bandyapadhaya K. Sundaralingam Amit Kumar Mondal 《Journal of the Geological Society of India》2010,75(1):128-136
The E-W running Salem-Attur shear zone demarcates the tectonic boundary between Archaean Dharwar Craton in the north and Proterozoic
Southern granulite terrane in the south. This study reveals that the shear zone is a low angle thrust. The thrust zone is
around 10 m thick and it merges with the main shear zone along the strike. The thrust is developed on charnockite near Odyarpatti,
which is retrograded into schists. Further, it is marked by gently dipping mylonitic foliation and subhorizontal lineation.
The S-C fabric, mantled porphyroclasts and intragranular faults indicate northeasterly slip along the thrust. Recumbent shear
folds SF1 are developed within the thrust zone. The thrust has been folded by late stage F2 fold which has brought variation in the orientation of the mylonitic foliation from subhorizontal to vertical attitude; the
mylonitic lineations have been rotated to subvertical orientation also. Additionally, the F2 crenulations and shear cleavages and intersection lineations are superimposed on the mylonitic fabric. Thrusting along the
Salem-Attur shear zone is probably the cause for upliftment of the charnockites to the upper crust. Post-upliftment stage
has witnessed brittle deformation in the form of development of shear fractures in NNE-SSW and E-W directions. Pseudotachylites
are emplaced along these fractures. 相似文献
15.
Summary Structural elements impressed upon the more easterly extensions of the Westralian shield were dominantly east-west features. These tendencies have channelled subsequent orogenies and geomorphic evolution, right down through the long history of the area.Possibly two major anticlinal zones were devoleped along east-west zones, to be preserved to the present day as mountainous ranges and inselbergs. Massive batholithic intrusions mark the more southern zone, whereas outcropping rocks in the more northerly zone are predominantly metasedimentary. The granite zone is one of intense negative Bouguer anomaly (–150 milligals) indicating a strong density contrast between these massive granites of low density and the foliated granite gneisses of the northern chain. The strength of the earth's crust, locally, must be immense to support such unbalanced load, and yet deep grabens with inliers of Upper Proterozoic and Ordovician sediments flank the negative anomaly on both margins. 相似文献
16.
基于西安地裂缝成因、基本特征和未来活动趋势分析,通过几何缩比为1：5的地裂缝活动模型试验和地裂缝活动对盾构隧道影响的数值模拟计算,研究了西安地铁2号线隧道正交穿越地裂缝带的设防参数。通过分析地裂缝年平均活动速率和历史最大活动量,确定了与地铁2号线相交的各条地裂缝的最大垂直位移量的预测值和设计建议值。模型试验和数值模拟结果表明,正交条件下地铁隧道在地裂缝活动地段的设防宽度为60 m,即上盘为35 m,下盘为25 m;沿隧道纵向地裂缝两侧地层变形规律呈现台阶状突变变形,隧道纵向设计可将上盘视为整体下降来考虑;地铁隧道穿越地裂缝带必须分段设缝以适应地裂缝的变形,其分段长度在地裂缝主影响区按10 m进行设防,在一般影响区可按10～15 m进行分段设防。研究结果可为地铁隧道穿越地裂缝带的结构设计提供参考。 相似文献
17.
Permo-Silesian movements between Baltica and Western Europe: tectonics and 'basin families' 总被引：1，自引：0，他引：1
Frank Mattern 《地学学报》2001,13(5):368-375
During the late Carboniferous, NW-trending faults of Central Europe's Bohemian Massif acted as a dextral shear zone between Baltica and Western Europe. During the early Permian, the shear sense was reversed, and a group of strike-slip basins formed along major NW-trending faults. This reversal is attributed to early Permian left-lateral motion between Baltica and Western Europe recorded by faults and basins of the Bohemian Massif. The Uralian orogeny is identified as the driving force for the sinistral motion between Baltica and Western Europe, shifting Baltica to the north-west along the Tornquist–Teisseyre zone. 相似文献
18.
In the Oman ophiolite, the large scale Makhibiyah shear zone, in Wadi Tayin massif was generated with no or little relative motion between the two adjacent blocks, in contrast with what is reported from otherwise similar shear zones in deep crust and upper mantle. This shear zone is asymmetrical with, along one margin an asthenospheric mantle (～1200 °C) and along the adjacent margin, a lithospheric mantle (～1000 °C). Within the hotter side and with increasing shear strain, horizontal flow lines smoothly swing towards the shear zone direction before abutting against the wall of the lithosphere side. Profuse mafic melts issued from the hotter mantle are frozen in the shear zone by cooling along this lithospheric wall. Tectonic and magmatic activities are entirely localized within the asthenospheric compartment. Mantle flow lines were rotated, during their channelling along this NW‐SE shear zone, in the NW and SE opposite directions. Depending on whether the flow lines are deviated NW or SE, dextral or sinistral shear sense is recorded in the shear band mylonitic peridotites. This demonstrates that the shear zone was not generated by strike‐slip motion, a conclusion supported by regional observations. 相似文献
19.
David R. Gray 《Journal of Structural Geology》1995,17(12)
Emplacement of an upper crustal, leading imbricate-fan thrust belt in the Lachlan Fold Belt of eastern Australia was accomplished along a 0.5–1 km thick zone of heterogeneously deformed, low grade phyllonite in pelitic rock. Continuous recrystallization and neocrystallization of mica in a zone of transposition layering has provided a weak zone at the base of a 100 km wide × 150 km exposed length × 10 km thick thrust system. The basal deformation zone is characterized by a low-moderately dipping, strong-intense transposition foliation enclosing elongate fault-bounded slices (up to 20 km long × 5 km wide in map view) of disrupted Cambrian metavolcanics and Upper Ordovician black shales and slates. These are derived from a structurally lower zone of duplexing or from the overturned limbs of anticlinorial structures. The detachment zone is a 10–15 km wide zone of intense deformation showing a transition from open, upright folds with weak cleavage to inclined, tightisoclinal folds with strong axial surface cleavage. The intensity of minor faults also increases into the zone. Leading imbricate fan thrust belts show maximum deformation effects along the basal detachment which forms the frontal or leading fault. The leading imbricate geometry is due to emplacement of the basal detachment zone up the lowest and last formed imbricate thrust. Movement is along a relatively ductile, low viscosity ‘layer’ at the base where strain softening occurs with development of transposition layering. This enables confined ‘flow’ along the basal zone with transport and emplacement of the fold system and duplex zone to higher structural levels. Reaction-enhanced ductility and grain boundary sliding may be important deformation mechanisms responsible for this flow. Localized polydeformation, marked by mesofolds and crenulation cleavage, reflects the interaction between thrust sheets and the movement on faults. 相似文献
20.
C. Schubert 《Tectonophysics》1979,52(1-4)
The El Pilar fault zone extends for about 700 km in an approximately E—W direction, from the Cariaco Trench to a point about 200 km northeast of Trinidad. It marks the southern boundary of the Araya—Paria peninsulas (eastern Caribbean Mts.) and of the Northern Range of Trinidad. It is characterized along its length by straight valleys, fault wedges, fumaroles, thermal springs, and sulfur deposits. The displacement along the El Pilar fault zone has been the subject of much controversy. Various authors recognize the following types of displacement: (1) southward thrust; (2) normal or graben faulting; (3) right-lateral strike-slip. The El Pilar fault zone probably represents a transform fault between the Caribbean and South America plates, and a hinge fault at its contact with the subduction zone east and south of the Lesser Antilles. It is planned to investigate the present-day movement along the El Pilar fault zone by high-precision geodetic methods, at the following localities: across the Gulf of Cariaco and at Casanay (central-southern Araya—Paria peninsulas). 相似文献