23 results on '"Tectonic controls"'
Search Results
2. Sedimentology and Sequence Stratigraphy of the Agrio Formation (Late Valanginian–Earliest Barremian) and the Closure of the Mendoza Group to the North of the Huincul High
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Pazos, Pablo José, Comerio, Marcos, Fernández, Diana Elizabeth, Gutiérrez, Carolina, Estebenet, María Candela González, Heredia, Arturo Miguel, Blondel, Philippe, Series Editor, Rabassa, Jorge, Series Editor, Horwood, Clive, Series Editor, Kietzmann, Diego, editor, and Folguera, Andrés, editor
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- 2020
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3. Caldera collapse and tectonics along the Main Ethiopian Rift: reviewing possible relationships
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Maestrelli, Daniele, Corti, Giacomo, Bonini, Marco, Montanari, Domenico, and Sani, Federico
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Main Ethiopian Rift ,Caldera collapse ,Peralkaline calderas ,Inherited faults ,Regional tectonics ,Caldera elongation ,Tectonic controls ,Geophysics. Cosmic physics ,QC801-809 ,Chemistry ,QD1-999 ,Geology ,QE1-996.5 - Abstract
The Main Ethiopian Rift (MER) represents an area where volcanism and tectonics interact to create closely linked volcano-tectonic features. This linkage is paramount in the axial portion of the rift, where magmatic segments localize several large peralkaline eruptive centres. Many of them evolved into caldera collapse (the best preserved of which are younger than ${
- Published
- 2021
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4. Sequence architecture and depositional evolution of the late Palaeogene in southwestern slope of Lufeng Depression, Pearl River Mouth Basin: Responses to tectonic processes and base‐level changes.
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Xia, Shiqiang, Li, Xin, Deng, Jimei, Luo, Donghong, Shu, Liangfeng, Wang, Shuzhi, Wu, Peng, Peng, Kai, Zhang, Xiangyang, Ji, Xinyuan, Liu, Huaming, and Ruffell, A.
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PALEOGENE , *WATERSHEDS , *BRAIDED rivers , *GEOMORPHOLOGY , *ARCHITECTURE , *SEQUENCE stratigraphy - Abstract
The southwestern slope of Lufeng Depression, which is located in the central part of Zhu I Depression is a significant geomorphic unit due to its petroliferous discoveries and tectonic evolutions since early Palaeogene. Based on the comprehensive analysis of cores, wireline logs, seismic volumes, and other related geological and geophysical information, the sequence architecture and depositional evolution was analysed, and their responses to regional tectonic processes and base‐level changes were revealed. The results indicated that two second‐order sequences and six third‐order sequences defined by different types of sequence boundaries are recognized. The second‐order and third‐order sequences were bounded by regional erosional unconformities on the depression margin or slope and unconformities in the central depression with the assist of stacking patterns of wireline logs and depositional characteristics of cores. The second‐order sequence generally consists of two regional transgressive–regressive cycles which can be further subdivided into several local sub‐cycles equivalent to corresponding third‐order sequences which can be identified from wireline logs and cores. The palaeogeomorphology resulted from compound and complex tectonic events in the early Palaeogene plays an important and main role in controlling sequence architecture. In contrast, the base‐level changes largely controls the sequence architecture in the late Palaeogene. The depositional systems within the sequence stratigraphic framework are mainly composed of braided delta deposits and shore deposits, which respectively includes braided channel, subaqueous distributary channel, lacustrine shale, beach bar, maximum flooding surface, shoreface, and foreshore. The base‐level changes, which apparently originated from tectonic uplift and subsidence and sediment supply, controlled the regional transgressions and regressions in sedimentary facies distributions. The development of subsequence (what we call it sand units or sections) from 2,980 to 2,880 in Enping Formation in the Early Palaeogene is obviously influenced by a decrease in tectonic subsidence (rifting stage) and an increase in accommodation space (base‐level rising), while the case is opposite in subsequence 2,850 of Enping Formation. However, the subsequence in Zhuhai Formation in the late Palaeogene from 2,760 to 2,600 was formed in stable tectonic settings (transition stage), and thereby, it was mainly dominated by base‐level changes which were caused by sediment supply and accommodation space changes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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5. Caldera collapse and tectonics along the Main Ethiopian Rift: reviewing possible relationships
- Author
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Maestrelli D.[1], Corti G.[1], Bonini M.[1], Montanari D.[1], and Sani F.[1
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Paleontology ,Tectonics ,Rift ,General Earth and Planetary Sciences ,Caldera ,Collapse (topology) ,Caldera collapse ,Caldera elongation ,Inherited faults ,Main Ethiopian Rift ,Peralkaline calderas ,Regional tectonics ,Tectonic controls ,Geology ,caldera collapse ,peralkaline calderas ,inherited faults ,regional tectonics ,caldera elongation ,tectonic controls ,General Environmental Science - Abstract
The Main Ethiopian Rift (MER) represents an area where volcanism and tectonics interact to create closely linked volcano-tectonic features. This linkage is paramount in the axial portion of the rift, where magmatic segments localize several large peralkaline eruptive centres. Many of them evolved into caldera collapse (the best preserved of which are younger than
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- 2022
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6. Environmental Controls and Facies Architecture of a Jurassic Carbonate Episode (La Manga Formation), Mendoza Province, Neuquén Basin
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Javier Martín-Chivelet, Ricardo Manuel Palma, Alberto Carlos Riccardi, Graciela S. Bressan, José López-Gómez, Kietzmann, Diego Alejandro, and Folguera Telichevsky, Andres
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geography ,geography.geographical_feature_category ,Outcrop ,TECTONIC CONTROLS ,Homocline ,Ciencias de la Tierra y relacionadas con el Medio Ambiente ,Sedimentary depositional environment ,chemistry.chemical_compound ,Paleontology ,chemistry ,CARBONATE RAMP ,Facies ,Carbonate ,Geología ,Siliciclastic ,SEA-LEVEL CHANGES ,CALLOVIAN-OXFORDIAN ,Reef ,CIENCIAS NATURALES Y EXACTAS ,Geology ,Sea level - Abstract
La Manga Formation is a vast carbonate system developed in the Neuquén Basin. The age is based in ammonite faunas, ranging from Early Callovian (Bodenbenderi-Proximum Zone) to Middle Oxfordian (Cordatum Standard Zone to Transversarium Standard Zone, and probably to the lower part of the Bifurcatus Standard Zone). A stratigraphical and sedimentological analysis, in the outcrops exposed in the south of Mendoza province, enabled the recognition of five facies associations of a carbonate ramp corresponding to (1) distal outer ramp, (2) proximal outer to distal middle ramp, (3) proximal middle ramp, (4) inner ramp deposits (shoreface, shoal, patch reef, shallow subtidal lagoon and tidal flat) and (5) paleokarstic facies. These facies correspond to homoclinal to distally steepened carbonate ramp. The facies associations are included into three third-order depositional sequences (DS-1, DS-2, DS-3) represented by transgressive and highstand systems tracts with sequence boundaries of regional character. Different controlling factors can be recognised in the deposition of this unit. The abrupt changes of facies, as well as paleokarst and epikarst discontinuity surfaces in the successions provide important evidence in terms of depositional environment and vertical evolution of the carbonate ramp. Facies patterns are variable across the outcrop area and vertically through time because of a combination of ramp morphology, siliciclastic supply, sea level changes and tectonic effects. In the southern sections, siliciclastic influx influenced the deposition of proximal middle ramp facies later overlain by scleractinian patch reefs which grew up throughout progressive stages from aggradational to progradational facies in response to climate controls and nutrient levels influence. In northern outcrops, tectonic controls affected the ramp topography and influenced the development of distal deep marine facies. Shallow subtidal and peritidal cycles indicate a combination of allocyclic and autocyclic processes controlling accommodation space and sediment accumulation. Fil: Palma, Ricardo Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Bressan, Graciela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Riccardi, Alberto Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: López Gómez, José. Universidad Complutense de Madrid; España. Consejo Superior de Investigaciones Científicas; España Fil: Martín Chivelet, Javier. Consejo Superior de Investigaciones Científicas; España. Universidad Complutense de Madrid; España
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- 2020
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7. Anorogenic granitoids of the Early Precambrian magmatism of the Ukrainian shield
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K.I. Sveshnikov, Y.T. Sukhorukov, I.K. Pashkevich, and S.S. Krasovsky
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granites ,rapakivi ,syenites ,tectonic controls ,igneous activity ,Ukrainian shield ,Proterozoic ,Ukraine ,Geology ,QE1-996.5 - Abstract
The Early Precambrian magmatism of the Ukrainian shield evolved through regular changes in tectonic setting, composition and depth of formation of rocks of three magmatic associations: (1) granitic, (2) diorite-granitic and (3) anorthosite-granitic. They correspond to the S, I, A - gtanite types respectively. The Early Proterozoic anorogenic granitoids of the Ukrainian shield are represented by the Korosten and Korsun-Novomirgorod rapakivi massifs, East-Peri-Asov complex of subalkaline granites, syenites and nepheline syenites, Perzhansk complex of subalkaline granites and rare-metal metasomatites. The anorogenic granitoids differ from magmatic rocks of the preceeding granitic and diorite-granitic associations by tectonic setting and composition. They are considered to belong to final stage of magmatic evolution and development of consolidated mature Early Proterozoic crust. The anorogenic granitoids of the Ukrainian shield are controlled by a major north-west linear magmatogenic structure, extending trough the whole Ukrainian shield to Poland.
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- 1993
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8. Paleogeographic and tectonic controls on the evolution of Cenozoic basins in the Altiplano and Western Cordillera of southern Peru
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Carlotto, Víctor
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PALEOGEOGRAPHY , *STRUCTURAL geology , *CENOZOIC Era , *SEDIMENTOLOGY , *GEOLOGICAL basins - Abstract
Abstract: Integrated studies of stratigraphy, sedimentology, paleogeography and tectonic controls on Cenozoic basins provide the basis for a series of time-slice reconstructions of basin evolution in the Andes of southern Peru. The Altiplano and adjacent margin of the Western Cordillera are characterized by several Paleocene–Miocene synorogenic continental basins with thicknesses locally exceeding 10km. The evolution of these basins has been controlled by NW-trending tectonic features that mark the Altiplano–Western Cordillera and Altiplano–Eastern Cordillera boundaries and the Condoroma structural high. Sedimentary deposits of Paleocene age preserved in the Altiplano are the result of nonmarine sedimentation in a distal foreland basin. During the early Eocene, predominantly dextral strike-slip movements in the Altiplano between the Cusco–Lagunillas and Urcos–Ayaviri fault systems created the transpressional Kayra basin. The Soncco and Anta basins (middle Eocene–early Oligocene) are related to NE shortening (43–30Ma) and represent proximal, wedge-top and foredeep basin environments preserved on the Altiplano. At ~29–28Ma, a change to predominantly E–W shortening produced sinistral strike-slip motion along NW-striking faults, resulting in intermontane, transpressional basins. In the Altiplano, the Tinajani and Punacancha (29–5Ma), and Paruro (12–6Ma) basins were controlled by the Cusco–Lagunillas and the Urcos–Ayaviri fault systems. The Maure, Tincopalca–Huacochullo and Condoroma basins (22–5Ma) of the Western Cordillera developed between the Condoroma high and the Cusco–Lagunillas fault system. Oligocene–Miocene sedimentation commonly evolved from proximal (alluvial) facies along the borders to distal (lacustrine) facies. These basins were linked to sinistral strike-slip faults that evolved into reverse-sinistral structures. Plate kinematics may play a role in Andean basin evolution, with deformation influenced by major preexisting faults that dictated paleogeographic trends, but orientations of regional compression that appear to coincide with the plate convergence direction. However, the processes of slab flattening and steepening exerted a primary control on regional crustal shortening and filling of synorogenic basins. [Copyright &y& Elsevier]
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- 2013
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9. Fluvial architecture as a response to two-layer lithospheric subsidence during the Permian and Triassic in the Iberian Basin, eastern Spain
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López-Gómez, José, Arche, Alfredo, Vargas, Henar, and Marzo, Mariano
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FLUVIAL geomorphology , *SEDIMENTARY basins , *PERMIAN stratigraphic geology , *TRIASSIC stratigraphic geology , *BIOSTRATIGRAPHY , *SEDIMENTATION & deposition , *PLATE tectonics - Abstract
Abstract: The stratigraphy of a sedimentary basin is mainly the result of the long-term response of a depositional surface to prolonged subsidence. However, the real nature of interrelations between fluvial architecture and subsidence is still unknown. Herein, we present new data on these relationships by combining the results of detailed sedimentological field work with data acquired through automated forward modelling and backstripping for the alluvial Permian and Triassic sediments of the SE Iberian Ranges. Using this methodology, we determined tectonic subsidence of the basin by means of backstripping analysis and crust and lithospheric mantle stretching factors (δ and β, respectively) using forward modelling technique. Results indicated that a configuration of two individual and independent layers during lithospheric subsidence for each tectonic phase fit better for this time of the studied basin evolution than the assumption of subsidence due to a single layer spanning the whole lithosphere. For this study, we simplified fluvial geometries as two main types: isolated (I) and amalgamated (A), with subtypes in each case. Different order bounding surfaces (b.s.) were distinguished in the field, although we only selected those affecting the whole basin under study. These included those b.s. of clear tectonic origin, ranging from individual basin boundary-fault pulses produced over periods of approximately 1My to those arising from major tectonic events, such as the beginning of extension in the basin, causing major changes in basin geometry over periods of 3–5My. The comparison of δ and β values and fluvial geometries for each identified tectonic phase in the basin evolution, revealed some possible relationship between subsidence and fluvial geometry: Sections showing the most varied fluvial architectural geometries, including ribbon and nested forms, were related to higher β and δ stretching factors values indicating tectonic phases of greater stretching and subsidence. When both stretching factors were similar and close to 1, fluvial geometry was basically reduced to amalgamated geometry type. Wider ranging of fluvial geometries was associated with stages of basin development in which crust and upper mantle activities differed, that is, showing larger differences of β and δ stretching factors values. The related slope changes are proposed as the main surface control of fluvial styles. Combination of subsidence with other possible controlling factors such as avulsion rate, climate or budget of sediments, gives rise to the definitive alluvial architecture of a basin. [Copyright &y& Elsevier]
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- 2010
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10. Aalenian pulses of tectonic activity in the Iberian Basin, Spain
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García-Frank, Alejandra, Ureta, Soledad, and Mas, Ramón
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PLATE tectonics , *CARBONATES , *GEODYNAMICS , *SEDIMENTS - Abstract
Abstract: In the northwest Iberian Range the Aalenian to Bajocian interval is represented by condensed, as well as more expanded marine carbonate strata deposited in a shallow epicontinental-sea setting. Precise biochronological data (successive ammonites assemblages) from 29 measured sections, along with a bed-by-bed facies analysis, allowed a detailed correlation between sections, the definition of a number of successive transgressive–regressive cycles and of two distinct sedimentation areas, as well as the compilation of isopach maps for short time intervals (duration of ammonites Zone/Subzone) and the assessment of sediment accumulation rates. Differences in facies and thickness in the studied interval, and the sequential organization, reveal significant changes in the depositional environment. A tectonically-controlled compartmentalization of the sedimentation area is suggested by a detailed reconstruction of the accumulation history. An active extensional tectonic regime is supported by contemporaneous volcanic activity in the southeastern Iberian Basin. A precise timing of the main tectonic pulses recorded in NW Iberian Basin for the Upper Toarcian–Lower Bajocian interval is presented, which may help to better resolve the stratigraphy in other W European during this time interval. [Copyright &y& Elsevier]
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- 2008
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11. Tectonic control on peritidal carbonate parasequence formation: an investigation using forward tectono-stratigraphic modelling.
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BENEDICTIS, DARIO DE, BOSENCE, DAN, and WALTHAM, DAVE
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STRUCTURAL geology , *PHYSICAL geology , *GEOLOGICAL formations , *CARBONATE rocks , *GEODYNAMICS ,QUATERNARY paleohydrology - Abstract
Studies of Quaternary extensional faults indicate that they have instantaneous amounts of throw (0·4 to 4 m), average slip rates (0·05 to 2·8 m kyr−1) and frequency of recurrence (<40 000 years) accounting for the accommodation space required for the accumulation of peritidal carbonate parasequences (PCPs). Hangingwall sites and graben are characterized by fault down-dropping together with regional subsidence, and footwall sites and horsts by fault-related uplift alternating with periods of regional subsidence. The relative sea-level curves generated by these processes operating in a maritime rift setting are used as inputs to a forward stratigraphic modelling program SedTec2000 to simulate how fault-related changes in accommodation space can account for high-frequency PCP formation. Each instantaneous fault slip generates a flooding surface or aggradation in hangingwall and graben settings. High-frequency cycles in hangingwall sites are either symmetric (deepening then shallowing upward) or asymmetric (shallowing-upward). The major factor controlling cycle types is the balance between rates of carbonate accumulation and generation of accomodation space. High-frequency cycles in footwall sites and horsts comprise shallow subtidal facies, with no distinctive bathymetric trends, capped by erosional boundaries generated by footwall uplift. The modelled cycles are of the same thickness, with bathymetric trends and frequency to cycles commonly interpreted to be due to orbitally driven eustatic sea-level changes or autocyclic processes. These numerical experiments demonstrate that high-frequency PCPs can be generated by tectonic, fault-related processes, a hypothesis that is frequently discounted. [ABSTRACT FROM AUTHOR]
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- 2007
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12. Importance of high-frequency tectonic sequences during greenhouse times of Earth history.
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Vakarelov, Boyan K., Bhattacharya, Janok P., and Nebrigic, Dragana D.
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PLATE tectonics , *STRUCTURAL geology , *STRATIGRAPHIC geology , *SEA level , *BENTONITE , *GEOLOGICAL time scales , *IGNEOUS rocks , *PHYSICAL geology , *EARTH (Planet) - Abstract
The relative importance of tectonism in the stratigraphic record should be more clearly expressed during greenhouse times of Earth history due to the lack of overmasking effects of high-frequency and high-amplitude sea-level changes typical for icehouse periods. Establishment of the importance of tectonism, especially at temporal scales comparable to durations of typical transgressive-regressive cycles, has been plagued by poor temporal resolution. Our outcrop and subsurface-based study of a Cenomanian shallow-marine siliciclastic interval, constrained by bentonite-based geochronology and detailed biostratigraphy, examines this problem. In a 2.2 m.y. interval, we identified four tectonically driven erosional surfaces that dominate preserved stratigraphy. Biostratigraphic correlation to a sea-level curve for the Cenomanian—where coeval high-frequency lowamplitude eustatic cyclicity has been demonstrated—allows the first direct comparison of the effects of eustasy and tectonics at temporal scales of hundreds of thousands of years during a global greenhouse time. We suggest that minor tectonic pulses locally overshadow the effects of eustasy and exert the dominant control over preserved stratigraphy. While subtle tectonic control on sedimentation has been documented throughout the Cretaceous Western Interior, the results of this study suggest that much of that deformation occurred at sub-million-year frequencies and at time scales comparable to eustatic transgressiveregressive cycles. [ABSTRACT FROM AUTHOR]
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- 2006
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13. The Hammamet, Gabe`s and Chotts basins (Tunisia): a review of the subsidence history
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Patriat, Martin, Ellouz, Nadine, Dey, Zied, Gaulier, Jean-Michel, and Ben Kilani, Hatem
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LAND subsidence , *STRUCTURAL geology - Abstract
We modeled the subsidence of three Mesozoic basins in Tunisia by using well data, seismic lines and field data. The results are presented here with an attempt to relate the succession of events deduced from the subsidence evolution analysis to the geodynamic evolution of the northern African margin.The Mesozoic and Cenozoic geological history of Tunisia has been broken down into two major periods separated by a transition period. The first period from Trias to Aptian was characterized by a constant subsidence of variable intensity spread over most of Tunisia, and over all the studied basins. This period was dominated by extension accompanying the Tethyan rifting during Trias–Lias. The transition period during the upper Cretaceous was characterized by extension and by the weak effects of far-seated compressional events. It is coeval with the first appearance of salt mobilization. The last period, in Tertiary, marked the appearance of the major collisional events, mostly during Neogene. During this last period, basins were characterized by very different behaviour, depending on their location: East or West of the North–South axis and close or not to the Tellian nappes.Among the three basins we studied, we paid special attention to the southernmost Gabe`s basin located south of the present eastern margin of Tunisia. The first-order evolution of its subsidence is similar to that we infer for most of the Tunisian basins. We emphasize the role of the structuration of the Gabe`s basin in the partition of the subsidence through time. [Copyright &y& Elsevier]
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- 2003
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14. Tectonic controls on kimberlite location, southern Africa
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Vearncombe, Susan and Vearncombe, Julian R.
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KIMBERLITE , *GEOLOGY - Abstract
The relationship between kimberlite (the host to diamonds) ascent paths from mantle depths >150 km to surface and major structures is controversial. We use a geometric method of spatial analysis (SpaDiS™), which requires neither statistics nor algebraic models to show that crustal architecture is critical in the localisation of kimberlites. Distinct corridors of kimberlites are parallel to, but not within, prominent shear zones and crustal faults. Instead the kimberlites occur in relatively homogeneous, strong crust capable of maintaining the very high CO2 pressures necessary for rapid emplacement. Archaean directional trends in kimberlite distribution are recognised on craton, whereas Proterozoic and Carboniferous–Permian (Karoo) age trends are recognised both on and off the Archaean craton. [Copyright &y& Elsevier]
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- 2002
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15. The copper history in the Anti Atlas belt,from Panafrican to Variscan orogeny, apersistence of tectonic controls: an overviewof Bou Azzer-El Graara inlier
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Bourque, Hugo, Barbanson, Luc, Sizaret, Stanislas, Branquet, Yannick, Al., Et, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Société Géologique de France, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Variscan ,Panafrican ,[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,copper deposits ,tectonic controls ,mineralogy ,textures ,Anti-Atlas - Abstract
National audience; The Anti-Atlas belt is well known for its numerous copper deposits.It displays also a complex geological, metallogenic andtectonic history which is challenging for mining companies in orderto better understand and prospect these Cu-deposits. In theBou Azzer-El Graara inlier, these deposits are hosted as well withinthe Precambrian basement as within the Neoproterozoic to Paleozoiccover. This study based on mapping, structural, mineralogy,textures and micro-textures observations present a synthesis ofCu-deposits at this inlier scale In this Neoproterozoic to Paleozoicsedimentary cover, two types of mineralizations are distinguished:one is related to local folds and faults and another one associatedwith a deformation localized in specific stratigraphic levels at thebase of the cover. Geological and mineralogical studies showedthat both Cu-ores types are controlled by the same hydrothermalevent associated to the Variscan orogeny. In the Precambrianbasement, massive copper sulfides lenses are present at the intersectionbetween regional pyritic beds or black shales and brittlefaults potentially associated with the late Panafrican deformation.Another kind of Cu-deposits is spatially associated with Panafricanshear zones, which showed ductile and brittle deformations. Thesemineralizations seem to be linked to the late brittle deformationthat re-used the ductile shear zones inherited from the Panafricanorogeny. During the Variscan compression, the reactivation, ofbasement-inherited Panafrican structures controlled the deformationresponsible of mineralization in the cover. In summary, coppermineralizations are closely associated with a brittle deformation,posterior to the ductile Panafrican deformation in the basementand synchronous with the Variscan orogeny in the cover. The metallogenichistory of copper in the Bou Azer-El Graara inlier canbe depicted through, at least, two models: (i) a two-stage model,with a first late Panafrican hydrothermal event, responsible for thebasement-hosted Cu-bodies and a second Variscan event, yieldingCu-deposits hosted in the cover. (ii) A single metallogenic phase,during Variscan deformation, that mineralized both the basementand the cover. Works in progress try to assess the relevance ofthese models at the Anti-Atlas scale.
- Published
- 2016
16. Anorogenic granitoids of the Early Precambrian magmatism of the Ukrainian shield
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I.K. Pashkevich, Y.T. Sukhorukov, K.I. Sveshnikov, and S.S. Krasovsky
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rapakivi ,Ukrainian ,Ukrainian shield ,lcsh:QE1-996.5 ,Geochemistry ,Geology ,Proterozoic ,granites ,language.human_language ,lcsh:Geology ,Precambrian ,syenites ,igneous activity ,Shield ,Magmatism ,language ,tectonic controls ,Ukraine - Abstract
The Early Precambrian magmatism of the Ukrainian shield evolved through regular changes in tectonic setting, composition and depth of formation of rocks of three magmatic associations: (1) granitic, (2) diorite-granitic and (3) anorthosite-granitic. They correspond to the S, I, A - gtanite types respectively. The Early Proterozoic anorogenic granitoids of the Ukrainian shield are represented by the Korosten and Korsun-Novomirgorod rapakivi massifs, East-Peri-Asov complex of subalkaline granites, syenites and nepheline syenites, Perzhansk complex of subalkaline granites and rare-metal metasomatites. The anorogenic granitoids differ from magmatic rocks of the preceeding granitic and diorite-granitic associations by tectonic setting and composition. They are considered to belong to final stage of magmatic evolution and development of consolidated mature Early Proterozoic crust. The anorogenic granitoids of the Ukrainian shield are controlled by a major north-west linear magmatogenic structure, extending trough the whole Ukrainian shield to Poland.
- Published
- 1993
17. Neogene evolution of the mixed carbonate-siliciclastic system in the Gulf of Papua, Papua New Guinea
- Author
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Bradley N. Opdyke, Luc Beaufort, Philippe Lapointe, Larry C. Peterson, Gerald R. Dickens, Samuel J. Bentley, James Daniell, André W. Droxler, Evgueni N. Tcherepanov, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA)
- Subjects
Atmospheric Science ,ice volume ,010504 meteorology & atmospheric sciences ,Carbonate platform ,fluctuations ,Soil Science ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,sea level ,Aquatic Science ,010502 geochemistry & geophysics ,Oceanography ,Neogene ,deposition ,01 natural sciences ,Sedimentary depositional environment ,chemistry.chemical_compound ,Paleontology ,platforms ,Geochemistry and Petrology ,foreland basin ,Earth and Planetary Sciences (miscellaneous) ,14. Life underwater ,tectonic controls ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology ,Tectonic subsidence ,Ecology ,Australia ,Forestry ,Geophysics ,great barrier reef ,chemistry ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Carbonate ,Siliciclastic ,Sedimentary rock ,sedimentation ,Paleogene ,Geology - Abstract
International audience; This paper outlines the evolution of the late Cenozoic mixed carbonate-siliciclastic depositional system in the Gulf of Papua (GoP), using seismic, gravity, multibeam bathymetry, well data sets, and Landsat imagery. The deposition of the mixed sedimentary sequences was influenced by dynamic interplay of tectonics, eustasy, in situ carbonate production, and siliciclastic sediment supply. The roles of these major factors are estimated during different periods of the GoP margin evolution. The Cenozoic mixed system in the GoP formed in distinct phases. The first phase ( Late Cretaceous-Paleocene) was mostly driven by tectonics. Rifting created grabens and uplifted structural blocks which served later as pedestals for carbonate edifices. Active neritic carbonate accumulation characterized the second phase (Eocene-middle Miocene). During this phase, mostly eustatic fluctuations controlled the large-scale sedimentary geometries of the carbonate system. The third phase ( late Miocene-early Pliocene) was characterized by extensive demise of the carbonate platforms in the central part of the study area, which can be triggered by one or combination of several factors, such as eustatic sea level fluctuations, increased tectonic subsidence, uplift, sudden influx of siliciclastics, or dramatic changes in environmental conditions and climate. The fourth phase ( late Pliocene-Holocene) was dominated by siliciclastics, which resulted in the burial of drowned and/or active carbonate platforms, although some platforms still remain alive until present-day.
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- 2008
- Full Text
- View/download PDF
18. Aalenian pulses of tectonic activity in the Iberian Basin, Spain
- Author
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García Frank, Alejandra, Ureta Gil, María Soledad, Mas Mayoral, José Ramón, García Frank, Alejandra, Ureta Gil, María Soledad, and Mas Mayoral, José Ramón
- Abstract
In the northwest Iberian Range the Aalenian to Bajocian interval is represented by condensed, as well as more expanded marine carbonate strata deposited in a shallow epicontinental-sea setting. Precise biochronological data (successive ammonites assemblages) from 29 measured sections, along with a bedby- bed facies analysis, allowed a detailed correlation between sections, the definition of a number of successive transgressive–regressive cycles and of two distinct sedimentation areas, as well as the compilation of isopach maps for short time intervals (duration of ammonites Zone/Subzone) and the assessment of sediment accumulation rates. Differences in facies and thickness in the studied interval, and the sequential organization, reveal significant changes in the depositional environment. A tectonically-controlled compartmentalization of the sedimentation area is suggested by a detailed reconstruction of the accumulation history. An active extensional tectonic regime is supported by contemporaneous volcanic activity in the southeastern Iberian Basin. A precise timing of the main tectonic pulses recorded in NW Iberian Basin for the Upper Toarcian–Lower Bajocian interval is presented, which may help to better resolve the stratigraphy in otherW European during this time interval., Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub
- Published
- 2008
19. Neogene evolution of the mixed carbonate-siliciclastic system in the Gulf of Papua, Papua New Guinea
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Tcherepanov, Evgueni N., Droxler, Andre W., Lapointe, Philippe, Dickens, Gerald R., Bentley, Sam J., Beaufort, Luc, Peterson, Larry C., Daniell, James, Opdyke, Bradley N., Tcherepanov, Evgueni N., Droxler, Andre W., Lapointe, Philippe, Dickens, Gerald R., Bentley, Sam J., Beaufort, Luc, Peterson, Larry C., Daniell, James, and Opdyke, Bradley N.
- Abstract
This paper outlines the evolution of the late Cenozoic mixed carbonate-siliciclastic depositional system in the Gulf of Papua (GoP), using seismic, gravity, multibeam bathymetry, well data sets, and Landsat imagery. The deposition of the mixed sedimentary sequences was influenced by dynamic interplay of tectonics, eustasy, in situ carbonate production, and siliciclastic sediment supply. The roles of these major factors are estimated during different periods of the GoP margin evolution. The Cenozoic mixed system in the GoP formed in distinct phases. The first phase ( Late Cretaceous-Paleocene) was mostly driven by tectonics. Rifting created grabens and uplifted structural blocks which served later as pedestals for carbonate edifices. Active neritic carbonate accumulation characterized the second phase (Eocene-middle Miocene). During this phase, mostly eustatic fluctuations controlled the large-scale sedimentary geometries of the carbonate system. The third phase ( late Miocene-early Pliocene) was characterized by extensive demise of the carbonate platforms in the central part of the study area, which can be triggered by one or combination of several factors, such as eustatic sea level fluctuations, increased tectonic subsidence, uplift, sudden influx of siliciclastics, or dramatic changes in environmental conditions and climate. The fourth phase ( late Pliocene-Holocene) was dominated by siliciclastics, which resulted in the burial of drowned and/or active carbonate platforms, although some platforms still remain alive until present-day.
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- 2008
- Full Text
- View/download PDF
20. Tectonic controls on alluvial deposition in the earliest syn-rift phase (South Pannonian Basin System, Croatia)
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Pavelić, Davor, Avanić, Radovan, Kovačić, Marijan, Pena dos Reis, Rui, Callapez, Pedro, and Dinis, Pedro
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tectonic controls ,alluvial deposition ,Pannonian Basin ,Croatia - Abstract
The Pannonian Basin System was formed as a result of continental collision of the European plate (Tisia-Moesia) with the African plate. Formation of its southern part began during Ottnangian time (Early Miocene) by continental rifting. The syn-rift phase lasted until the Middle Badenian (Middle Miocene), and resulted in the formation of elongated half-grabens characterized by large sediment thicknesses strongly influenced by tectonics and gradually increasing volcanism. The Lower Miocene sedimentary complex of the south Pannonian Basin System, i.e. North Croatian Basin, unconformably overlies pre-Miocene basement, and is represented by fresh-water deposits which belong to the earliest syn-rift phase of basin evolution. Deposition of the lower part of the fresh-water complex occurred in alluvial environments while the upper part was characterized by lacustrine sedimentation. Alluvial deposits have been measured at the Kalnik, Medvednica and Požeška Mts.. The main characteristics of these deposits the domination of coarse-grained over fine-grained sediments, conspicuous variation in grain size, very rapid lateral and vertical facies alternations, occurrences of red beds and a lack of fauna. The sediments form many small fining- and rarely coarsening-upward cycles. These cycles are typical of alluvial fans and braided rivers as a consequence of the autocyclic process on the surface. The deposits are divided into eleven facies: 1. Bcn ; massive breccia, clast-supported: rock-fall, 2. Gmu ; massive conglomerates, matrix-supported: plastic debris flow, 3. Gmi ; massive conglomerates, matrix-supported, rare clast-supported: pseudoplastic debris flow, 4. Gc ; massive conglomerates, clast-supported: main fan-trench, longitudinal bar, 5. Gp ; planar cross-bedded conglomerates, clast-supported: tranverse bar, 6. Ge ; pebble to granule conglomerates, lenses: stream flows, crevasse channel, 7. Sh ; fine- to coarse grained sandstones, horizontal lamination: upper flow regime, 8. Sr ; fine- to coarse grained sandstones, cross-lamination: lower flow regime, 9. Se ; fine- to coarse grained sandstones, lenses: crevasse splay, 10. F1 ; siltstones, massive, brown colour: flood plain, abandoned channel, 11. F2 ; siltstones, scattered granules, calcrete, reddish colour: palaeosol. Kalnik Mt.. The conglomerate bodies interpreted as longitudinal and transverse bar deposits, and the lack of sediments deposited by gravity flows suggest a pebbly braided river in the upper part of the succession. The lower part of the succession is characterized by dominant flood plain over channel deposits indicating deposition in the lower alluvial plain of the braided river. The unusually thick flood plain deposits could be attributed to rapid subsidence of the basin by tectonic influences, when the possibility of erosion of fine-grained deposits is minimal. Medvednica Mt.. The domination of coarse-grained deposits accumulated on longitudinal bars, pedogenic occurrences and the lack of fossils suggest a pebbly braided river. Alluvial deposits are sharply overlain by lacustrine limestones indicating tectonic deepening of the basin. Požeška Mt.. The association of sediments deposited by rock-fall and debris flow mechanisms with deposits of longitudinal bars, flood-plains and palaeosol indicates deposition in alluvial environments, relatively close to the source area, probably in the alluvial fan. The predominance of sediments deposited by traction in the fan succession seems closer to the braided alluvial fan. One of the measured sections shows a fining-upwards megacycle which is expressed by a general decrease in fragment size in the coarse-grained deposits and the occurrence of thick calcretes near the top of the megacycle, followed by gradual decreasing of the conglomerate unit thickness. This megacycle is interpreted as the result of normal faulting along the active margin of the subsiding basin. The deposition of rock-fall breccias also indicates the very high intensity of tectonic activity, and trapping of coarse-grained clastics near the steep slopes in the proximity of the source area.
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- 2004
21. Tectonic controls on lacustrine sedimentation on Mt. Medvednica (Ottnangian, Pannonian Basin System, North Croatia)
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Pavelić, Davor, Avanić, Radovan, Zupanič, Jožica, and Clemmensen, Lars B.
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Croatia ,Pannonian basin system ,lake ,tectonic controls - Abstract
The Ottnangian (late Early Miocene) succession in the Mt. Medvednica (North Croatia) consists of a lower, alluvial portion and an upper, lacustrine portion. The lower portion overlies pre-Neogene basement, and may attain a thickness of approximately 100 m. It is dominated by poorly stratified, pebble to cobble conglomerates, which reflect deposition within braided-stream systems. General direction of streams was toward the NE. The coarse-grained character of these systems reflects the activation of faults at the closely situated active tectonic margins of the depositional basin. Coarse-grained alluvium is sharply overlain by upper, lacustrine portion of Ottnangian succession, which consists of three different parts. The sharp transition from coarse-grained alluvium to the fine-grained swamp and peat deposits is regarded to have been a consequence of extensional tectonics, which caused subsidence, enlargement of the depositional area, i.e. the activation of new faults situated farther from the previous basin margins. The swamp and peat deposits are overlain by carbonate deposits of lake margin, and rhytmites and thin turbidites in the deeper lake realms, which reflect continued subsidence. In this part of the succession there are rare thin intercalations of pyroclastics. Lower part of lacustrine deposits may be some 55 m thick. The second part of the lacustrine deposits, which may be more than 45 m thick, shows a coarsening-upward trend with an increase of the proportion of clastic deposits. Sands and gravels reflect a delta progradation ending with coarse-grained material. These gravels are sharply overlain by the third part of the lacustrine Ottnangian succession, which is dominated by silts. The relevant change must have been caused by renewed tectonic activity, i.e. the activation of extensional faults. The silts contain fresh-water gastropods, and may contain rare intercalations of gravels deposited from gravity flows. The fresh-water deposition was ended by Karpatian (latest Early Miocene) marine transgresssion and deposition of marine silts. This transgression is known from other parts of the Pannonian Basin System and has been explained by tectonic events.
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- 1999
22. Tectonic and geomorphic controls on the fluvial styles of the Eslida Formation, Middle Triassic, Eastern Spain
- Author
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Arche, Alfredo, López Gómez, José, Arche, Alfredo, and López Gómez, José
- Abstract
The Eslida Fm is an alluvial unit of the Buntsandstein Facies of the Iberian Ranges deposited in a half-graben basin over a period of 2–2.5 Ma during the lower Anisian (Middle Triassic). It can be subdivided into six cycles that can be correlated along the basin. The overall architecture and cyclicity were controlled by the episodic activity of the basin boundary fault. Two proximal source areas of minor importance and a distal one of major importance are identified. The petrological composition of the sandstones is arkosic to subgrauwackic, indicating source areas containing both low-metamorphic rocks and gneiss, and granitic rocks. Alluvial fans, very common in rift basins, were not developed because of slow fault scarp retreat and the lack of large antecedent rivers cutting across the rift shoulders. Paleocurrents point to the SE, except for a zone in the middle part of the basin where interference with a NE–SW fault system deflected the channels to the S. The infilling of the basin is asymmetric in a transverse section, with channel facies near the basin boundary fault to the NE and overbank facies in the distal SW part., Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub
- Published
- 1999
23. Hydrologic, magmatic and tectonic controls on hydrothermal flow, Taupo volcanic zone, New Zealand: implications for the formation of epithermal vein deposits.
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Rowland J.V., Simmons S.F., Rowland J.V., and Simmons S.F.
- Abstract
Most of the geothermal systems of the Taupo zone occur in a 150 km rifted arc dominated by silicic volcanism, associated with major faults near calderas or within accommodation zones that transfer extension between rifts, and are hosted by 1-3 km thick volcanic deposits resting unconformably on Mesozoic argillites and greywackes. Flow regimes and permeability controls in one extinct and six active systems show that flow is generally controlled by intrusion-driven convection, host porosity/permeability, fault-fracture networks produced by tectonism, volcanism and/or dyke emplacement, vertical eruption conduits, and the heterogeneity resulting from hydrothermal alteration and mineral deposition. Such controls influence flow within three depth zones: a feed zone below 2 km, an intermediate zone of epithermal mineralisation and a discharge zone at depths shallower than 200 m. The permeability structure conducive to vein formation is vertically long but only tens to hundreds of metres wide, where episodic flux over time scales from decades to millennia accumulates sufficient gold and silver to form orebodies., Most of the geothermal systems of the Taupo zone occur in a 150 km rifted arc dominated by silicic volcanism, associated with major faults near calderas or within accommodation zones that transfer extension between rifts, and are hosted by 1-3 km thick volcanic deposits resting unconformably on Mesozoic argillites and greywackes. Flow regimes and permeability controls in one extinct and six active systems show that flow is generally controlled by intrusion-driven convection, host porosity/permeability, fault-fracture networks produced by tectonism, volcanism and/or dyke emplacement, vertical eruption conduits, and the heterogeneity resulting from hydrothermal alteration and mineral deposition. Such controls influence flow within three depth zones: a feed zone below 2 km, an intermediate zone of epithermal mineralisation and a discharge zone at depths shallower than 200 m. The permeability structure conducive to vein formation is vertically long but only tens to hundreds of metres wide, where episodic flux over time scales from decades to millennia accumulates sufficient gold and silver to form orebodies.
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