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1.
ABSTRACT A calcite mass more than 1·5 km long and 20 m wide crops outs along the faulted margin of the Albian carbonate platform of Jorrios in northern Spain. The mass contains abundant dissolution cavities up to 7 m long and 1 m high, filled with cross‐stratified quartz sandstone and alternating sandstone–calcite laminae. Similar cavities are also present in a 50‐m‐wide zone of platform limestones adjacent to the calcite mass that are filled with limestone breccias and sandstone. The calcite mass has mean δ18O values of 19·6‰ (SMOW), whereas platform limestones have mean δ18O values of 24·4‰ (SMOW). Synsedimentary faulting of the carbonate margin and circulation of heated fault‐related waters resulted in replacement of a band of limestone by calcite. Soon after this replacement, dissolution by undersaturated fluids affected both the calcite mass and the adjacent limestones. Percolating marine quartz sand filled all dissolution cavities, sometimes alternating with precipitating calcite. The resulting cavities and fills, which recall products of meteoric diagenesis, are attributed to a hydrothermal origin based on their geometry, occurrence along the profile and synsedimentary tectonic relationships. The early faulting and diagenesis are related to local extensional tectonism in a large‐scale strike‐slip setting. Movements occurred during the early dispar/appenninica zone of the Late Albian.  相似文献   

2.
笔者从冲断活动的产物———各种成因扇体(冲积扇、水下扇、扇三角洲)出发,由160口单井剖面、15条联井剖面、8个层位平面渐次展开了准噶尔西北缘前陆冲断带三叠—侏罗纪逆冲断裂活动的沉积响应研究。三叠纪扇体在乌尔禾—夏子街地区发育叠置程度最好,T1b到T3b,其由盆内向盆缘老山方向退缩迁移明显,并具T1b到T2k1由盆缘向盆内、T2k2到T3b由盆内向盆缘迁移的2个进退波动变化。侏罗纪扇体在八道湾组最为发育,总体叠置关系较差,J1b到J2t,均呈由盆内向盆缘老山退缩沉积的退覆式迁移特征。三叠纪到侏罗纪,总体为由强到弱的退覆式冲断活动及扇体迁移模式,即随主要同生控扇断裂分布由盆缘向老山方向退缩迁移,冲断活动强度由盆缘向盆地方向逐渐减弱直至停息;相应地,各期扇体平面上分布规模渐小,总体呈由盆内向盆缘老山退缩迁移的沉积响应,两者耦合性良好。各类扇体的沉积分布受不同时期同生断裂活动的严格控制,其时空叠置及迁移规律的差异是红山嘴—车排子、克拉玛依—百口泉及乌尔禾—夏子街各构造带冲断作用地域性及作用强度差异性的沉积响应。进而引入“活动性指数”的概念与方法,对前陆冲断带同生断裂的冲断活动强度进行了定量化统计分析,并根据冲断推覆事件的地层、沉积标识划分出T1b-T3b、J1b-J2x、J2t三套构造层序,识别出三叠—侏罗纪的3个逆冲推覆幕、6次逆冲推覆事件。  相似文献   

3.
A detailed investigation of floodbasin facies architecture was undertaken in the Upper Triassic (Carnian-Rhaetian) Callide Coal Measures in east-central Queensland, Australia, using extensive highwall and exploration borehole data from ongoing mining activities. The composite Callide Seam Member varies up to 23 m in thickness and is locally split by a number of clastic partings up to several metres thick, ranging from claystone to coarse sandstone. A subset of the nine lithofacies recognized in surface exposures was identified from geologists' logs of cored and uncored drillholes through the Callide Seam Member. Facies mapping of each clastic parting (split) was then undertaken using all available highwall and drilling data. Sequential maps of facies and interval thickness for each coal body and clastic parting over the mine area (6000 × 2500 m) record sediment accumulation in alluvial channel and floodbasin environments (including levees, splays and splay complexes, and mires). The maps indicate that the numerous splays have dominantly elongate plan geometry (up to 4 km long), with lesser irregular and rare lobate shapes. Small, elongate splays were evidently formed during single flood events, whereas larger, elongate bodies and more irregularly shaped complexes were the product of longer-term splay construction over several flood cycles. Quantitative summaries of splay dimensions indicate a wide variety of shape and size. The distribution of splay orientations is similar to the palaeocurrent distribution in major alluvial channel deposits as established from cross-bedding. Alluvial channels that sourced the splays and other clastic sediments within seam splits were of low sinuosity, braided planform, constructed sediment bodies up to 2800 m wide and were dominantly loaded rather than incised into underlying peat-rich substrates.  相似文献   

4.
Synsedimentary faults result in the direct interaction between tectonic and sedimentary processes at similar spatio-temporal scales. Sedimentological analysis of sediment-laden gravity flows in the northern part of the Grès d'Annot Formation (Sanguinière sub-basin, Col de la Moutière/Tête Ronde) has revealed the presence of fault scarps of metre-scale height. These synsedimentary fault scarps were sufficient to disturb the sediment gravity flow dynamics resulting in (i) a strong variation of the erosive behaviour of a concentrated flow and (ii) the transformation of a strongly stratified, laminar hyperconcentrated flow into a turbulent flow, in short distance (less than 500 m). These disturbances develop without the flows being deviated by the fault scarps but produce great facies heterogeneity, the least homogeneous facies (mixing sand and clay) being localized on the upstream obstacle side, the most homogeneous (massive sand) downstream.  相似文献   

5.
The River Supersequence represents a 2nd‐order accommodation cycle of approximately 15 million years duration in the Isa Superbasin. The River Supersequence comprises eight 3rd‐order sequences that are well exposed on the central Lawn Hill Platform. They are intersected in drillholes and imaged by reflection seismic on the northern Lawn Hill Platform and crop out in the McArthur Basin of the Northern Territory. South of the Murphy Inlier the supersequence forms two south‐thickening depositional wedges on the Lawn Hill Platform. The northern wedge extends from the Murphy Inlier to the Elizabeth Creek Fault Zone and the southern wedge extends from Mt Caroline to the area south of Riversleigh Station. On the central Lawn Hill Platform the River Supersequence attains a maximum thickness of 3300 m. Facies are dominantly fine‐grained siliciclastics, but the lower part comprises a mixed carbonate‐siliciclastic succession. Interspersed within fine‐grained facies are sharp‐based sandstone and conglomeratic intervals interpreted as lowstand deposits. Such lowstand deposits represent a wide range of depositional systems and palaeoenvironments including fluvial channels, shallow‐marine shoreface settings, and deeper marine turbidites and sand‐rich submarine fans. Associated transgressive and highstand deposits comprise siltstone and shale deposited below storm wave‐base in relatively quiet, deep‐water settings similar to those found in a mid‐ to outer‐shelf setting. Seismic analysis shows significant fault offsets and thickness changes within the overall wedge geometry. Abrupt thickness changes across faults over small horizontal distances are documented at both the seismic‐ and outcrop‐scales. Synsedimentary fault movement, particularly along steeply north‐dipping, largely northeast‐trending normal faults, partitioned the depositional system into local sub‐basins. On the central Lawn Hill Platform, the nature of facies and their thickness change markedly within small fault blocks. Tilting and uplift of fault blocks affected accommodation cycles in these areas. Erosion and growth of fine‐grained parts of the section is localised within fault‐bounded depocentres. There are at least three stratigraphic levels within the River Supersequence associated with base‐metal mineralisation. Of the seven supersequences in the Isa Superbasin, the River Supersequence encompasses arguably the most dynamic period of basin partitioning, syndepositional faulting, facies change and associated Zn–Pb–Ag mineralisation.  相似文献   

6.
大庆长垣南部两翼葡萄花油层油气运移及聚集规律   总被引：2，自引：0，他引：2  
大庆长垣南部构造两翼葡萄花油层油气资源丰富,但油水分布复杂、油气聚集成藏规律认识不清,导致两翼油气资源探明率低、探明储量动用效果差。利用测井、地震、试油和地球化学分析数据,在系统油源对比基础上,结合断裂系统划分标定油源断裂,分析断裂与砂体配置关系对油气运移、聚集的控制,建立成藏模式。研究得出,大庆长垣南部葡萄花油层油主要来自于本地下伏青一段源岩,主要排烃期为明水组沉积末期及其后,因此,坳陷期形成、反转期继续活动的断层以及断陷期形成、坳陷期和反转期继续活动的断裂为主要油源断裂,油气沿油源断裂垂向运移至葡萄花油层,受砂体规模及断层侧向封闭性限制,油气在葡萄花油层中侧向运移距离较短;油源断裂为主要控藏断裂,宏观控制葡萄花油层油水平面分布,油源断裂与砂体空间配置控制着油气聚集层位及范围;油源断裂下盘、反向断阶、单斜式地垒和顺向断阶等高位断块为两翼有利油气聚集部位。  相似文献   

7.
Backstripped basement subsidence histories from both the hanging wall and the footwall blocks adjacent to synsedimentary normal faults can be used to reconstruct the sense of fault motion through time and to quantify the vertical component of fault slip. Consequently, apparent dip-slip rates of faults can be calculated for each stratigraphic interval and times of increased fault activity can be distinguished. An application of this method to well data along a transect through the central part of the Miocene Vienna Basin indicates that two distinct phases of faulting occurred during the Karpatian, with rates as high as 3000 m Myr−1. Changes in the sense of movements during the early Karpatian and the earliest Badenian indicate a major rearrangement in the fault patterns. During the early Sarmatian another short pulse of dip-slip is recorded along the investigated faults.  相似文献   

8.
《Journal of Structural Geology》1999,21(8-9):1131-1142
Using spatial relationships between individual plutons and faults to support genetic correlations between faulting and magmatism is meaningless since even random magmatic or tectonic processes will result in some plutons adjacent to faults. Our initial analyses of populations of faults and Carboniferous plutons in the Armorican Massif, France and faults and Alleghanian plutons in the southern Appalachians, USA indicate that plutons have broad distributions with respect to faults but with a tendency for plutons to occur away from faults. Maxima of integrated pluton areas occur at 1/4 (Appalachians) and 1/2 (Armorican) of the distance between the average fault spacing in these orogens. Although there is a great need for statistical evaluations of relationships between populations of igneous bodies and structures in a wide variety of settings and crustal depths, our initial studies suggest that faults do not preferentially channel magma during ascent or emplacement and that these are relatively unfocused processes within orogenic belts.  相似文献   

9.
通过对鄂尔多斯盆地上三叠统延长组野外露头、岩心剖面的细致研究,发现深湖区发育有类型多样的同沉积变形构造。露头剖面中见有同沉积砂岩墙、砂泥岩脊、砂岩脉、微断层和褶皱变形构造等,岩心中也观察到砂岩揉皱构造,砂泥质角砾,微断层和砂岩脉等变形构造,在对其特征描述和层系结构分析的基础上,结合三角洲前缘砂体向深湖区滑塌形成富含火焰状构造的鲍马层系,指出同沉积构造成因与古地震作用关系密切。时间上同沉积变形构造与火山灰沉积物几乎同期发育,相伴而生,且略早于广泛发育的长7浊积岩; 古地震、邻区火山作用或深部热作用导致盆地基底沉降、山体隆升,有利于滑塌浊积岩的形成。空间上同沉积变形构造主要分布于盆地南部和西南部,并且从南西至北东方向有强度减弱的趋势。综合对比同期周邻造山带的演化历史及深湖区同沉积变形构造的分布特征后认为,同沉积变形构造是对盆地南部秦岭碰撞造山和盆地内深部热作用的耦合响应,指示了深湖盆发育期对应于盆地构造相对活动的动力学背景,对同期优质烃源岩的发育有重要贡献。  相似文献   

10.
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11.
第四纪断层上断裂活动的群集及迁移现象   总被引：16，自引：1，他引：16  
对许多第四纪断层上形成地表破裂的巨大滑动事件及错动位移状况的具体研究表明,在不同时间段它们的数量和强度是变化的,不均匀的。这种断层活动的不均匀性主要表现在两个方面:一是滑动事件的发生往往集中于一定的地段和一定的时间段,并与相对平静的阶段相交替,即所谓断裂活动的群集性;另一方面的表现是集中发生滑动事件段落(或区域)在空间上的迁移变化。这是中国大陆内部第四纪断层活动所表现出的主要特征之一。这方面的实例可见于许多活断层上。如沿郯庐断层、鲜水河断层以及河西走廊断裂带、阿尔金断裂带等。深入研究第四纪断层活动的这一不均匀特性对正确评估活断层的活动程度和潜在地震危险性具有实际应用意义。  相似文献   

12.
Growth faulting is a common feature of many deltaic environments and is vital in determining local sediment dispersal and accumulation, and hence in controlling the resultant sedimentary facies distribution and architecture. Growth faults occur on a range of scales, from a few centimetres to hundreds of metres, with the largest growth faults frequently being under‐represented in outcrops that are often smaller than the scale of feature under investigation. This paper presents data from the exceptionally large outcrops of the Cliffs of Moher, western Ireland, where a growth‐fault complex affects strata up to 60 m in thickness and extends laterally for ≈ 3 km. Study of this Namurian (Upper Carboniferous) growth‐fault system enables the relationship between growth faulting and sedimentation to be detailed and permits reconstruction of the kinematic history of faulting. Growth faulting was initiated with the onset of sandstone deposition on a succession of silty mudstones that overlie a thin, marine shale. The decollement horizon developed at the top of the marine shale contact for the first nine faults, by which time aggradation in the hangingwall exceeded 60 m in thickness. After this time, failure planes developed at higher stratigraphic levels and were associated with smaller scale faults. The fault complex shows a dominantly landward retrogressive movement, in which only one fault was largely active at any one time. There is no evidence of compressional features at the base of the growth faults, thus suggesting open‐ended slides, and the faults display both disintegrative and non‐disintegrative structure. Thin‐bedded, distal mouth bar facies dominate the hangingwall stratigraphy and, in the final stages of growth‐fault movement, erosion of the crests of rollover structures resulted in the highest strata being restricted to the proximity of the fault. These upper erosion surfaces on the fault scarp developed erosive chutes that were cut parallel to flow and are downlapped by the distal hangingwall strata of younger growth faults.  相似文献   

13.
The Fall River Formation is a 45 m thick layer of fluvial-dominated valley-fills and shore-zone strata deposited on the stable cratonic margin of the Cretaceous Western Interior Seaway. Fall River deposits in Red Canyon, in the south-west corner of South Dakota (USA), expose a cross-section of a 3.5 km wide valley-fill sandstone and laterally adjacent marine deposits. The marine deposits comprise three 10 m thick upward-shoaling sequences; each composed of multiple metres-thick upward-coarsening successions. The lower two of these sequences are laterally cut by the valley-fill sandstone, and are capped by metres-thick muddy palaeosols. The upper sequence spans the top of the valley-fill sandstone, and is overlain by the Skull Creek Shale. The 30 m thick valley sandstone is partitioned into four distinct fills by major erosion surfaces, and each of these fills contain many metres-thick channel-form bodies. Deposits in the lower parts of these fills are sheet-like, top-truncated channel bodies, whereas deposits in the upper parts of fills are upward-concave, laterally amalgamated channel bodies, more completely preserved heterolithic channel bodies, or wave-deposited sheets. Each valley-fill basal erosion surface records an episode of valley incision and relative sea-level fall, and the gradual progression from fluvial to more estuarine deposits upwards within each fill records relative sea-level rise. All fills are dominantly channel deposits and are capped by marine flooding surfaces. The dominance of channel deposits, the gradual change to more estuarine facies in the upper parts of fills, and the location of flooding surfaces at valley-fill tops all suggest that sediment supply initially kept pace with relative sea-level rise and valleys filled during late marine lowstand and transgression, not during subsequent highstands. Recently proposed facies models have focused on variations in the relative strength of tide, wave and river currents as controls on valley-fill deposits. However, relative rates of sediment supply and basin accommodation change, and the shift in this ratio along the depositional profile during multiple-scale cycles in relative sea-level, are equally important controls on the style of valley-fill deposits.  相似文献   

14.
The Munébrega Plio-Quaternary half-graben is a NW-SE trending neotectonic depression located in the central sector of the intraplate Iberian Range (NE Spain). The master fault of the half-graben offsets an Upper Pleistocene pediment deposit, forming an upslope-facing scarp. A trench dug across the fault scarp exposed a 25-m wide deformation zone consisting of graben and horst fault blocks with fissures in the upper part of the scarp, and a monoclinal flexure affected by normal and reverse faults in the lower part of the scarp. We infer a minimum of three faulting events over the past 72 ka, yielding an average (maximum) recurrence interval of 24 ka. The oldest event (72–41 ka) produced an antislope scarp on the relict pediment surface, confining deposition to the downthrown block. Cross-cutting faults affecting sedimentary units deposited in the sediment trap produced by the first event provide evidence for at least two younger events (33–19? ka). The measured cumulative vertical displacement (7.4 m) yield a minimum vertical slip rate of 0.10 ± 0.01 mm/year (2σ error) for the past 72 ka. If the paleoearthquakes ruptured the whole mappable length of the fault (ca. 20 km), they probably had moment magnitudes ca. 6.9 (Stirling et al. Bull Seismol Soc Am, 2002). Such earthquakes would have been more than a magnitude unit larger than the largest ones recorded historically in the Iberian Range. These results suggest that the official seismic hazard assessments, based solely on the historic and instrumental record, may underestimate the seismic hazard in the area.  相似文献   

15.
山东灵山岛滑塌体内部沉积及构造特征研究   总被引：1，自引：0，他引：1  
青岛市灵山岛修船厂剖面下白垩统地层中发育良好的滑塌变形体。野外观察可见滑塌体岩性单元主要由厚层砂岩及砂页岩互层组成,其中厚层砂岩根据其沉积构造及成因机制可分为砂质碎屑流沉积及浊流沉积两类;砂页岩互层段砂岩层可见底模构造及粒序层理,为静水环境下远端浊流沉积。滑塌体内部构造主要可分为软褶皱变形、同生断层、透镜状砂质团块三种类型。其中,软褶皱变形根据岩性可分为砂岩软褶皱、砂页岩互层软褶皱及页岩软褶皱,随着变形强度增加,软褶皱枢纽逐渐平行于滑移方向,形成曲脊软褶皱或软鞘褶皱(soft sheath folds);同生断层出现在砂岩层中,根据力学性质分为正断层及逆断层,正断层为剪切拉伸所致,逆断层为软褶皱逆冲所致;透镜状砂质团块包括同沉积布丁构造和同沉积断块。根据滑塌体内部滑移面识别出三期滑塌,完整的滑塌体由底部拆离滑移面、下部厚层砂体、中部砂页岩互层及上部砂页岩互层未变形体组成,其组成特征及各部分接触关系反映了滑塌体中下部沿底部拆离滑移面发生滑塌变形,且于活动末期在相对静水条件下被上部砂页岩互层覆盖这一形成过程。根据滑塌体内部组成特征的有序性、相似性及滑塌体内部沉积构造特征,推测其触发机制可能为沉积物快速沉积所引发的重力滑塌成因。  相似文献   

16.
This paper analyzes throw-depth (T-z) profiles from a high resolution 2D reflection seismic grid in the central basin of Lake Malawi to investigate whether evidence exists: 1) for migration of faulting away from the border fault of the half-graben; and 2) that faults in the hangingwall lengthened over the last 1.3 million years. We use the high-precision age model from a 2005 scientific drilling project in our study area to constrain the ages of our seismic horizons and examine a fault array and two individual faults within the hangingwall of the central basin border fault. We account for climatic and sedimentological controls on stratal growth with a lake-level curve that accompanies the age model. A comparison of our hangingwall T-z profiles with published throw-distance (T-x) profiles for the border fault shows synchronous faulting over the last 1.3 m.y. rather than basinward migration of faulting. Furthermore, we find no evidence for significant propagation of the tips of the hangingwall faults in the last 1.3 m.y. and conclude that the lack of basinward migration of faulting is a consequence of strain localization on faults established at an early stage in basin development.  相似文献   

17.
The benefits of geologic analysis for roof-control studies and hazard prediction in coal mines are well documented. Numerous case studies have illustrated the importance of recognizing geologic features such as paleochannels, coal riders, and kettlebottoms in mine roofs. Relatively understudied features, in terms of mining, are paleoslumps .Paleoslumps represent ancient movement and rotation of semi-consolidated sediment. Because bedding in paleoslumps is deformed or inclined, these features cause instability in mine roofs, haul roads, surface highwalls, and other excavations. Various types of paleoslumps above coals in the Eastern Kentucky Coal Field were studied in order to aid in their recognition and prediction in mines.The paleoslumps studied all showed characteristic slump-deformation features, although some differences in magnitude of deformation and overall slump size were noted. Coals beneath slumps often exhibited folding, reverse displacements, truncation, clastic dikes, and locally increased thickness. Slumps are inferred to have been triggered by a wide range of mechanisms, such as loading of water-saturated sediment on rigid substrates, synsedimentary faulting, and over-pressurization of channel margin and bar slopes.Analysis of paleoslumps in underground mines, where paleoslumps are viewed from beneath rather than in profile is difficult, since characteristic bed rotation may not be conspicuous. Sudden increases in bed-dip angle inferred from changes in rock type or bedding contacts in the roof; occurrence of bounding, polished rotation surfaces; or roof irregularity and occurrence of loading features may indicate the presence of paleoslumps. Another key to recognition may be the sudden appearance of over-thickened coal, which can occur because of slump-created paleotopography, synsedimentary faults, and slump-generated overthrusting. In addition, steeply inclined, folded, or transported coal marginal to paleoslumps can create apparent increases in coal thickness in cores. Although thick coals are obviously a target of exploration, anomalously thick coals may actually indicate adjacent paleoslumps accompanied by hazardous roof conditions and loss of seam thickness.  相似文献   

18.
The Umbria-Marche foreland fold-and-thrust belt in the northern Apennines of Italy provides excellent evidence to test the hypothesis of synsedimentary-structural control on thrust ramp development. This orogenic belt consists of platform and pelagic carbonates, Late Triassic to Miocene in age, whose deposition was controlled by significant synsedimentary extension. Normal faulting, mainly active from Jurassic through Late Cretaceous-Paleogene time, resulted in significant lateral thickness variability within the related stratigraphic sequences. By Late Miocene time the sedimentary cover was detached from the underlying basement and was deformed by east-verging folds and west-dipping thrusts. Two restored balanced cross sections through the southernmost part of the belt show a coincidence between the early synsedimentary normal faults and the late thrust fault ramps. These evidences suggest that synsedimentary tectonic structures, such as faults and the related lithological lateral changes, can be regarded as mechanically important controlling factors in the process of thrust ramp development during positive tectonic inversion processes.  相似文献   

19.
本文在岩心观察和描述的基础上,结合地震、测井等资料及平面上砂体的分布形态,对惠民凹陷西部沙四下亚段的沉积特征及成因进行了研究。认为研究区沙四下亚段主要发育冲积扇沉积的泥石流扇和辫状河扇两种类型,共识别出了6种沉积微相。宁南断层和无南断层下降盘发育大面积的辫状河扇沉积。砂体垂直岸线分布,延伸距离较远。平面上分布呈扇形,沉积相带分异不明显,主要沉积微相为辫状河道、河道砂坝与河道间沉积。邻近齐广断层断崖处发育泥石流扇沉积,砂体不甚发育,与辫状河扇相比,该沉积类型砾岩富集,扇体规模较小。相带变化比较明显,主要沉积微相为泥石流沉积、河道沉积与漫流沉积。该沉积体系的形成主要受构造活动、古地貌、物源区性质与古气候等因素的影响,断裂活动是该沉积体系形成的决定性因素。  相似文献   

20.
The Upper Cretaceous Cerro Toro Formation in the Silla Syncline, Parque Nacional Torres del Paine, Magallanes Basin, Chile, includes over 1100 m of mainly thin‐bedded mud‐rich turbidites containing three thick divisions of coarse conglomerate and sandstone. Facies distributions, stacking patterns and lateral relationships indicate that the coarse‐grained sandstone and conglomerate units represent the fill of a series of large south to south‐east trending deep‐water channels or channel complexes. The middle coarse division, informally named the Paine member, represents the fill of at least three discrete channels or channel complexes, termed Paine A, B and C. The uppermost of these, Paine C, represents a channel belt about 3·5 km wide and its fill displays explicit details of channel geometry, channel margins, and the processes of channel development and evolution. Along its northern margin, Paine C consists of stacked, laterally offset channels, each eroded into fine‐grained mudstone and thin‐bedded sandy turbidites. Along its southern margin, the Paine C complex was bounded by a single, deeply incised but stepped erosional surface. The evolution of the Paine C channel occurred through multiple cycles of activity, each involving: (i) an initial period of channel erosion into underlying fine‐grained sediments; (ii) deposition of coarse‐grained pebble to cobble conglomerate and sandstone within the channel; and (iii) waning of coarse sediment deposition and accumulation of a widespread sheet of fine‐grained, thin‐bedded turbidites inside and outside the channel. The thin‐bedded turbidites deposited within, and adjacent to, the channel along the northern margin of the Paine C complex do not appear to represent levée deposits but, rather, a separate fine‐grained turbidite system that impinged on the Paine C channel from the north. The Cerro Toro channel complex in the Silla Syncline may mark either an early axial zone of the Magallanes Basin or a local slope mini‐basin developed behind a zone of slope faulting and folding now present immediately east of the syncline. If the latter, flows moving downslope toward the basin axis further east were diverted to the south by this developing structural high, deposited part of their coarse sediment loads, and exited the mini‐basin at a point located near the south‐eastern edge of the present Silla Syncline.  相似文献   

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