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1.
《Geodinamica Acta》2003,16(2-6):149-169
The Calabria–Peloritani Arc southern terrane is a stack of crystalline basement nappes, some of them provided with a widely outcropping Alpine sedimentary cover, sealed by clastics of the Stilo–Capo d’Orlando Formation (SCOF). New field observations in the Stilo area lead to define a Pignolo Formation as a sedimentary cycle predating the emplacement of the uppermost nappe (Stilo Unit) of the tectonic pile. It includes the well-known Lithothamnium and larger foraminifers bearing calcarenites, previously interpreted as a basal member of the SCOF. The biostratigraphic revision of both formations, together with recently published data about other preorogenic deposits, point to a stacking of the whole terrane between the Aquitanian and the middle–late Burdigalian. A comparison between the sedimentary cycles characterising the Calabria–Peloritani southern terrane during the Oligocene–Early Miocene and those almost coeval of the Betic–Rifian internal units highlights their quite similar evolution. Thus it is reliable that both the orogenic belts originated from contiguous paleogeographic realms. These considerations confirm that the present western Mediterranean Chains were originally segments of a continuous orogenic belt disrupted by the opening of the Balearic and Tyrrhenian basins.  相似文献   

2.
The eastern Central Alps consist of several Pennine nappes with different tectonometamorphic histories. The tectonically uppermost units (oceanic Avers Bündnerschiefer, continental Suretta and Tambo nappes, oceanic Vals Bündnerschiefer) show Cretaceous/early Tertiary W-directed thrusting with associated blueschist facies metamorphism related to subduction of the Pennine units beneath the Austroalpine continental crust. This event caused eclogite facies metamorphism in the underlying continental Adula nappe. The gross effect was crustal thickening. The tectonically lower, continental Simano nappe is devoid of any imprint from this event. In the course of continent-continent collision, high- T metamorphism and N-directed movements occurred. Both affected the whole nappe pile more or less continuously from amphibolite to greenschist facies conditions. Crustal thinning commenced during the regional temperature peak. A final phase is related to differential uplift under retrograde P–T conditions. Further thinning of the crust was accommodated by E- to NE-directed extensional deformation.  相似文献   

3.
In the Rif (northern Morocco) and the Western Betics (southern Spain), the Alboran Domain forms a complex stack of metamorphic nappes including mantle peridotites (Beni Bousera and Ronda). We present in this paper new temperature data obtained in the Alboran Domain based on Raman spectroscopy of carbonaceous material (RSCM thermometry). In the lower metamorphic nappes of the Alboran Domain (lower Sebtides–Alpujárrides) temperature ranges from > 640 °C at the base of the metapelitic sequence to 500 °C at the top. The relationships between field isotherms and nappe structure show that peak temperatures were reached during strong ductile thinning of these nappes whereas they partly postdate this main episode in the Rif. In the upper nappes of the Alboran Domain (Ghomarides–Maláguides), generally supposed to be only weakly metamorphosed, temperatures range from ~500 °C at their base down to < 330 °C at the top. This temperature gradient is consistent with progressive Cenozoic resetting of K–Ar and 40Ar–39Ar ages. These nappes were thus affected by a significant thermal metamorphism, and the available age data in the underlying Sebtides–Alpujárrides show that this metamorphism is related to the metamorphic evolution of the whole Alboran Domain during the Late Oligocene–Early Miocene. Such thermal structure and metamorphic evolution can be explained by generalized extension in the whole Alboran Domain crustal sequence. At a larger scale, the present thermal structure of the Alboran Domain is roughly spatially consistent around the Beni Bousera peridotites in the Rif, but much more affected by late brittle tectonics around the Ronda peridotites in the Western Betics. Therefore, on the basis of the observed thermal structure, the metamorphic evolution of the Alboran Domain can be interpreted as the result of the ascent of hot mantle units contemporaneous with thinning of the whole lithosphere during an Oligo‐Miocene extensional event. The resulting structure has however been dismembered by late brittle tectonics in the Western Betics.  相似文献   

4.
The main terrains involved in the Cretaceous–Tertiary tectonism in the South Carpathians segment of the European Alpine orogen are the Getic–Supragetic and Danubian continental crust fragments separated by the Severin oceanic crust-floored basin. During the Early–Middle Cretaceous times the Danubian microplate acted initially as a foreland unit strongly involved in the South Carpathians nappe stacking. Multistage folding/thrusting events, uplift/erosion and extensional stages and the development of associated sedimentary basins characterize the South Carpathians during Cretaceous to Tertiary convergence and collision events. The main Cretaceous tectogenetic events responsible for contraction and crustal thickening processes in the South Carpathians are Mid-Cretaceous (“Austrian phase”) and Latest Cretaceous (“Laramide” or “Getic phase”) in age. The architecture of the South Carpathians suggests polyphase tectonic evolution and mountain building and includes from top to bottom: the Getic–Supragetic basement/cover nappes, the Severin and Arjana cover nappes, and Danubian basement/cover nappes, all tectonically overriding the Moesian Platform. The Severin nappe complex (including Obarsia and Severin nappes) with Late Jurassic–Early Cretaceous ophiolites and turbidites is squeezed between the Danubian and Getic–Supragetic basement nappes as a result of successive thrusting of dismembered units during the inferred Mid- to Late Cretaceous subduction/collision followed by tectonic inversion processes.

Early Cretaceous thick-skinned tectonics was replaced by thin-skinned tectonics in Late Cretaceous. Thus, the former Middle Cretaceous “Austrian” nappe stack and its Albian–Lower Senonian cover got incorporated in the intra-Senonian “Laramide/Getic” stacking of the Getic–Supragetic/Severin/Arjana nappes onto the Danubian nappe duplex. The two contraction events are separated by an extensional tectonic phase in the upper plate recorded by the intrusion of the “Banatitic” magmas (84–73 Ma). The overthrusting of the entire South Carpathian Cretaceous nappe stack onto the fold/thrust foredeep units and to the Moesian Platform took place in the Late Miocene (intra-Sarmatian) times and was followed by extensional events and sedimentary basin formation.  相似文献   


5.
黔东南地区构造特征   总被引:2,自引:2,他引:2  
黔东南地区构造复杂,发育有多期次,不同组合类型的构造形迹,通过构造解析划分出了顺层韧性剪切带,阿尔卑斯式褶皱,侏罗山式褶皱,过渡性剪切带,逆冲推覆构造及地垒-地式构造等组合类型,它们分别产出于造山前期伸展背景,造山带,造山带前陆和造山后地壳隆升背景,反映了该区不同时期构造类型及构造演化特征。  相似文献   

6.
7.
逆冲推覆构造研究进展和今后探索趋向   总被引:17,自引:0,他引:17  
朱志澄 《地学前缘》1995,2(1):51-58
本文概述了70年代中期以来逆冲推覆构造研究的几个方面,指出逆冲推覆构造广泛产出于不同大地构造单元,今后应注意造山带内尤其是活动性高的地台上这类构造的研究。台阶式结构是逆冲构造的基本型式,但对各种模型应采取分析态度。文章分析了与逆冲推覆系相关的褶皱构造及其产出关系。逆冲推覆构造常呈一定型式产出,以隆起构造为中心的背冲和以构造拗陷为中心的对冲是具有普遍品格的模式。挤压性推覆与伸展滑覆常密切伴生,并与构造热隆作用相关,常常表现为推覆→侵入→滑覆的规律性顺序。笔者最后提出了这类构造今后研究的意见。  相似文献   

8.
Understanding the exhumation process of deep-seated material within subduction zones is important in comprehending the tectonic evolution of active margins. The deformation and slip history of superficial nappe pile emplaced upon high-P/T type metamorphic rocks can reveal the intimate relationship between deformation and transitions in paleo-stress that most likely arose from changes in the direction of plate convergence and exhumation of the metamorphic terrane. The Kinshozan–Atokura nappe pile emplaced upon the high-P/T type Sanbagawa (= Sambagawa) metamorphic rocks is the remnant of a pre-existing terrane located between paired metamorphic terranes along the Median Tectonic Line (MTL) of central Japan. Intra- and inter-nappe structures record the state of paleo-stress during metamorphism and exhumation of the Sanbagawa terrane. The following tectonic evolution of the nappes is inferred from a combined structural analysis of the basal fault of the nappes and their internal structures. The relative slip direction along the hanging wall rotated clockwise by 180°, from S to N, in association with a series of major tectonic changes from MTL-normal contraction to MTL-parallel strike-slip and finally MTL-normal extension. This clockwise rotation of the slip direction can be attributed to changes in the plate-induced regional stress state and associated exhumation of the deep-seated Sanbagawa terrane from the Late Cretaceous (Coniacian) to the Middle Miocene.  相似文献   

9.
造山带逆冲推覆构造研究的主要新进展   总被引:9,自引:0,他引:9  
造山带逆冲推覆构造研究是造山带研究中最为重要的课题之一。造山带外带即前陆褶皱冲断带(主要发育盖层冲断推覆体,一般遵循薄皮构造变形规则)与造山带内带(主要是基底褶皱推覆体,呈现厚皮构造变形规律)结晶逆冲推覆构造的几何学、运动学特征存在较大差异,二者形成机制也不相同,但其间仍有紧密的联系。近20年来造山带逆冲推覆构造研究的主要新进展为:①前陆褶皱冲断带逆冲断层及其相关褶皱的几何学特征分析已趋定量化,对其组合类型与演化时序有了更全面的认识,且对前陆褶皱冲断带的发展演化模式取得了新的共识,即遵循临界库仑楔模式;②平衡剖面技术在前陆褶皱冲断带的应用已从二维平衡与复原演进到三维平衡与复原,且日渐计算机化;③对造山带内带结晶基底逆冲推覆构造的主要类型(C型与F型逆冲岩席)及其特征已有较深的理解;④对前陆褶皱冲断带与结晶基底逆冲构造的相互关系及其形成演化模式有了新认识。目前造山带逆冲推覆构造研究过程中存在的主要问题为:①造山带内带结晶逆冲推覆构造的研究比较薄弱;②造山带晚期走滑构造及伸展构造的叠加与改造使得造山带内结晶逆冲推覆构造更为复杂化,致使其研究难度加大;③全面、精细的造山带深部地球物理资料较缺乏;④造山带内结晶逆冲岩席变形变质历史与超高压变质岩的形成机制及折返过程之间的关系尚未揭示清楚。在今后研究过程中应加强对上述问题的深入研究。  相似文献   

10.
The southern and eastern Karkonosze-Izera massif (northern Bohemian Massif) exposes blueschist facies rocks and MORB-type magmatic complexes. During Late Devonian to Early Carboniferous times, these were overthrust within a nappe pile toward the NW onto the pre-Variscan Saxothuringian basement composed of the Izera-Kowary metagranitoids and their envelope. The lowermost nappe (or parautochthonous?) unit of the pile is the low-grade metamorphosed Jewt3d complex, comprising a Devonian to Early Carboniferous sedimentary succession of the Saxothuringian passive margin. This is tectonically overlain by the South Karkonosze complex, which represents Ordovician-Silurian volcano-sedimentary infill of the Saxothuringian basin, affected by Late Devonian HP metamorphism. The uppermost nappe is the Early Palaeozoic epidote-amphibolite grade Leszczyniec MORB-like complex, cropping out on the eastern margin of the Karkonosze-Izera massif. It probably represents a fragment of obducted Saxothuringian basin floor. The nappe pile was stacked beneath the overriding upper plate margin, now concealed below the Intra-Sudetic basin and hypothesized to represent a fragment of the Tepla-Barrandian terrane. The nappe stacking, triggered by buoyancy-controlled upward extrusion of the subducted continental slab, was the main mechanism for the exhumation of HP rocks. The final stages of the NW-ward nappe stacking were accompanied and followed by SE-directed Early Carboniferous extensional collapse. The lower plate of the suture zone was uplifted at that time and intruded by the ~330-Ma-old, nearly undeformed Karkonosze granite pluton. As a result of the collapse, the Tepla-Barrandian(?) upper plate was downthrown on shear zones and brittle faults and buried under several km-thick synorogenic Late Tournaisian(?) through Namurian and post-orogenic Late Carboniferous-Early Permian succession of the Intra-Sudetic basin. The south and east Karkonosze suture most probably is a fragment of the Tepla/Saxothuringian (Münchberg-Tepla) suture belt known from the western Bohemian Massif.  相似文献   

11.
In the Central Taurides, the Sultan Mountains comprise in ascending order the Çimendere unit and the Ak?ehir, Do?anhisar, Çay nappes composed of metasedimentary sequences deposited from Cambrian to Tertiary. The overthrust of the Çay nappe on the Lutetian Celepta? formation representing the uppermost stratigraphic position in the Çimendere unit indicates that the latest nappe emplacement occurred during the Middle Eocene. The Oligocene and Miocene rocks are in post-tectonic facies in the west Central Taurides. The kinematic data from these nappes related to closure of the Neotethys reveal a top-NE shear sense in the northwest part and a top-SE shear sense in the southeast part of the Sultan Mountains. The Sultan Mountains are located in the north part of the Isparta Angle which was tectonically assembled by the Lycian, Hoyran–Bey?ehir–Hadim and Antalya allochthons on the Bey Da?lar? and Anamas–Akseki autochthons from the Latest Cretaceous to the Late Pliocene. The previous paleomagnetic data showed that the west and east subsections of the Isparta Angle were subjected to post-Eocene 30°–40° anticlockwise and clockwise rotations, respectively. In consideration of these paleomagnetic data, the kinematic data measured in the Sultan Mountains might be restored into approximately E–W-trending linear fabric associated with a top-E shear sense. These new kinematic data from the nappes in the Sultan Mountains disagree with the existing tectonic models that suggest N–S nappe translation over the Central Taurides during the latest Cretaceous–Middle Eocene. The alternative tectonic model for the Antalya nappes in the core of the Isparta Angle related to east–west compression suggests westward and eastward nappe emplacements on the surrounding autochthons. However, the new kinematic data presented here point consistently to a top-E shear sense in all tectonostratigraphic units in the Sultan Mountains currently located in the north part of the Anamas–Akseki autochthon.  相似文献   

12.
This paper presents a structural analysis of the external zone of Alpine Corsica, including the autochthonous domain and overlying external nappes (Santa Lucia and Balagne nappes). Two stages of nappe emplacement are identified occurring prior to and after the deposition of the Eocene sediments which were laid down upon first generation thrust contacts but are imbricated with their composite (continental and ophiolitic) basement by second generation thrusts. Five generations of structures with regional extent have been distinguished. However, the first generation has not been recognized within the visible part of the autochthon domain.Eoalpine first generation structures, restricted to allochthonous units, and Late Eocene to Early Oligocene second generation structures were nearly contemporaneous with the two stages of thrusting. The precise significance of E-W third generation structures is poorly understood. Broadly N-S fourth generation structures resulted from Oligocene compressive tectonics (folding and local backthrusting). Finally, fifth generation structures were generated during a Miocene extensional stage.These results are partly consistent with structural features previously reported in the southern and the northern outcrops of the Schistes lustrés, i.e. the main part of the allochthonous domain. A summary of a regional tectonic evolution is thus proposed for Alpine Corsica from Eoalpine obduction to Miocene extension.  相似文献   

13.
The Southeast Anatolian orogen is a part of the eastern Mediterranean-Himalayan orogenic belt. Development of the Southeast Anatolian orogen began with the first ophiolite obduction onto the Arabian platform during the Late Cretaceous, and it continued until the Miocene. Its lingering effects continue to be discernible at present. During the Late Cretaceous-Miocene interval, three major deformational phases occurred, related to Late Cretaceous, Eocene, and Miocene nappe emplacements. The Miocene nappes are composed of ophiolites and metamorphic massifs.

For a decade, field studies in the region have shown that strike-slip tectonics played a role complementary to the major horizontal effects of the nappe movement, as indicated by: (1) fault systems active during the Eocene; (2) different Eocene rock units composed of coeval continental and deep-sea deposits and presently tectonically juxtaposed; and (3) other stratigraphic and structural data obtained across the present strike-slip fault zones.

These strike-slip faults possibly resulted from oblique subduction of the mid-oceanic ridge underneath the northerly situated Yuksekova ensimatic island-arc complex, causing a gradual cessation of the island-arc system. The subduction also led to the development of a back-arc pull-apart basin, i.e., the Maden basin, which opened on the upper plate. The geologic history in Southeast Anatolia resembles the development of the San Andreas fault system and subsequent tectonic evolution.  相似文献   

14.
The boundary zone between two Penninic nappes, the eclogite-facies to ultrahigh-pressure Zermatt-Saas zone in the footwall and the blueschist-facies Combin zone in the hanging wall, has been interpreted previously as a major normal fault reflecting synorogenic crustal extension. Quartz textures of mylonites from this fault were measured using neutron diffraction. Together with structural field observations, the data allow a refined reconstruction of the kinematic evolution of the Pennine nappes. The main results are: (1) the contact is not a normal fault but a major thrust towards northwest which was only later overprinted by southeast-directed normal faulting; (2) exhumation of the footwall rocks did not occur during crustal extension but during crustal shortening; (3) the Sesia-Dent Blanche nappe system originated from a continental fragment (Cervinia) in the Alpine Tethys ocean, and the Combin zone ophiolites from the ocean basin southeast of Cervinia; (4) out-of-sequence thrusting played a major role in the tectonic evolution of the Penninic nappes. An erratum to this article can be found at  相似文献   

15.
The classical concept of the nappe structure of the central Northern Calcareous Alps (NCA) is in contradiction with modern stratigraphic, structural, metamorphic and geochronological data. We first perform a palinspastic restoration for the time before Miocene lateral tectonic extrusion, which shows good continuity of structures, facies and diagenetic/metamorphic zones. We present a new nappe concept, in which the Tirolic unit practically takes the whole area of the central NCA and is divided into three subunits (nappes): Lower and Upper Tirolic subunit, separated by the Upper Jurassic Trattberg Thrust, and the metamorphic Ultra-Tirolic unit. The Hallstatt (Iuvavic) nappe(s) formed the highest unit, but were completely destroyed by erosion after nappe stacking. Remnants of the Hallstatt nappes are only represented by components of up to 1 km in size in Middle/Upper Jurassic radiolaritic wildflysch sediments ("Hallstatt Mélange" belonging to the Tirolic unit). Destruction of the continental margin started in Middle to Upper Jurassic time and prograded from the oceanic side towards the shelf. The original substratum of the external nappes (Bavaric units) of the NCA was largely the Austroalpine crystalline basement, of the internal nappes (Tirolic units) the weakly metamorphosed Palaeozoic sequences (Greywacke Zone and equivalents). Eocene movements caused limited internal deformation in the Tirolic unit.  相似文献   

16.
The thermotectonic evolution of the East Alpine Rhenodanubian flysch zone (RDFZ) and the collisional history along the orogenic front is reconstructed using apatite fission-track (FT) thermochronology. The apatite FT data provides evidence for a burial depth of at least 6 km for the samples, which were totally reset. Burial was not deeper than 11 km, since the zircon fission-track system was not reset. The RDFZ represents an accretionary wedge with a complex burial and cooling history due to successive and differential accretion and exhumation. The sedimentary sequences were deposited along a convergent margin, where accretion started before Maastrichtian and lasted until Miocene. Accretion propagated from a central area (Salzburg-Ybbsitz) both to the west and to the east. In the west, accretion lasted from Middle Eocene to Early Oligocene, reflecting underplating of the RDFZ by the European continental margin sediments. In the east, where three nappes (Greifenstein, Kahlenberg and Laab nappes) can be distinguished, the exhumation started between Late Oligocene and Early Miocene. The Kahlenberg and Laab nappes show total resetting of the apatite FT ages, while in the Greifenstein nappe there is only partial resetting. According to a new paleogeographic reconstruction, the Kahlenberg and Laab nappes were placed on top of the Greifenstein nappe by an out-of-sequence thrust.  相似文献   

17.
The distribution of aromatic hydrocarbons and stable carbon isotope ratios of organic matter in a series of nine Miocene Embalut coal samples obtained from nine coal seams of Kutai Basin, East Kalimantan, Indonesia were studied. The rank of the Embalut coals ranged from lignites to low rank sub-bituminous coals (0.36–0.50% Rr), based on measurements of huminite reflectance. The aromatic hydrocarbon fractions of all coal samples were dominated by cadalene in the lower boiling point range and picene derivatives in the higher boiling point range of the gas chromatograms. Cadalene can be attributed to the contribution of Dipterocarpaceae and various hydrated picenes to the contribution of additional angiosperms to the coal forming vegetation. The picenes originate from alpha- and beta-amyrin. However, in some coal samples minor amounts of simonellite and retene were also detected which argues for an additional contribution of gymnosperms (conifers) to coal forming vegetation preferentially in the Middle Miocene and at the beginning of the Late Miocene. The results of stable carbon isotope ratios (δ13C) in most of the coal samples are consistent with their origin from angiosperms (δ13C between ?27.0‰ and ?28.0‰). During the Miocene the climate of Mahakam Delta was not uniformly moist and cooler than the present day climate. This would have been favourable for the growth of conifers, especially in the montane forests. The contribution of conifers to the Embalut coals might be a result of the cool Middle/Late Miocene climate during peat accumulation in the Kutai Basin.  相似文献   

18.
福建省大田县广平含煤区推覆构造特征及找煤预测   总被引:1,自引:0,他引:1  
陈开彪 《中国煤田地质》2006,18(2):16-17,70
通过对区内推覆构造及地层等的研究,认为广平含煤区推覆体下蕴藏着丰富的煤炭资源,童子岩组煤系地层埋藏深度主要受发育于童子岩组上部的F1、F2推覆断层控制,并圈定出煤炭资源预测前景较好的3个区作为煤炭勘查后备基地。  相似文献   

19.
The nappe pile presently cropping out in the central sector of the Ligurian Alps, is represented by some principal groups of tectonic units. Starting from the foreland, the outer and lower, weakly metamorphic (up to 0.3 GPa) Briançonnais units support the high-pressure (up to 1.3 GPa) ensemble of inner Briançonnais nappes, in turn overridden by the Prepiedmont units, sourced from the European continental margin. Prepiedmont units form two superposed groups. The lower is composed only of a pre-Namurian basement (Alpine metamorphism up to 0.6 GPa); and the upper is mainly composed of a slightly metamorphic (greenschist facies) post-Namurian cover. At the top lie the high-pressure metamorphosed (up to 0.8 GPa in the sector here considered) ophiolitic units. The group of the non-metamorphic Helminthoid Flysch nappes (original stratigraphic cover of the ophiolitic units) has travelled the greatest distance and is presently mainly set onto the outer part of the chain. Only events up to the stacking of the nappe pile are discussed, disregarding late-stage deformation. As the examined sector is located at a considerable distance from the collisional zone, late processes did not change the overall order of superposition formerly acquired. The model proposes the development of two major, subhorizontal detachment surfaces. The first, shallower one confines at the base a very thin-skinned set of nappes, nearly totally made up of Prepiedmont sedimentary covers that are bounded at their top by the Helminthoid Flysch units. Both these groups underwent a mainly horizontal outwards transport. In contrast, the underlying Prepiedmont crust and the adjoining Briançonnais inner sector (separated by the second, deeper major detachment surface) were progressively dragged into the subduction zone under the ophiolitic units and duplexes were generated. Exhumation of the metamorphic units occurred along the subduction channel, as did stacking of the nappe pile.  相似文献   

20.
In the area of Arosa?CDavos?CKlosters (Eastern Switzerland) the different tectonic elements of the Arosa zone mélange e.g. the Austroalpine fragments, the sedimentary cover of South Penninic ophiolite fragments, as well as the matrix (oceanic sediments and flysch rocks) show distinctively different metamorphic histories and also different climaxes (??peaks??) of Alpine metamorphism. This is shown by a wealth of Kübler-Index, vitrinite and bituminite reflectance measurements, and K-white mica b cell dimension data. At least six main metamorphic events can be recognized in the area of Arosa?CDavos?CKlosters: (1) A pre-orogenic event, typical for the Upper Austroalpine and for instance found in the sediments at the base of the Silvretta nappe but also in some tectonic fragments of the Arosa zone (Arosa zone mélange). (2) An epizonal oceanic metamorphism observed in the close vicinity of oceanic basement rocks units of the Arosa zone (South Penninic) is another pre-orogenic process. (3) A metamorphic overprint of the adjacent Lower Austroalpine nappes and structural fragments of the Lower Austroalpine in the Arosa zone. This metamorphic overprint is attributed to the orogenic metamorphic processes during the Late Cretaceous. (4) A thermal climax observed in the South Penninic sediments of the Arosa zone can be bracketed by the Austroalpine Late Cretaceous event (3) and the middle Tertiary event (5) in the Middle Penninic units and predates Oligocene extension of the ??Turba phase??. (6) North of Klosters, in the northern part of our study area, the entire tectonic pile from the North Penninic flysches to the Upper Austroalpine is strongly influenced by a late Tertiary high-grade diagenetic to low-anchizone event. In the Arosa zone mélange an individual orogenic metamorphic event is evidenced and gives a chance to resolve diagenetic?Cmetamorphic relations versus deformation. Six heating episodes in sedimentary rocks and seven deformation cycles can be distinguished. This is well explained by the propagation of the Alpine deformation front onto the foreland units. Flysches at the hanging wall of the mélange zone in the north of the study area (Walsertal zone) show data typical for low-grade diagenetic thermal conditions and are therefore sandwiched between higher metamorphic rock units and separated from theses units by a disconformity. The Arosa zone s.s., as defined in this paper, is characterised by metamorphic inversions in the hanging wall and at the footwall thrust, thus shows differences to the Walsertal zone in the north and to the Platta nappe in the south.  相似文献   

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