Under the compressional regime imposed by the flat slab and expansion of the fold and thrust belt and consequent crustal thickening, middle Miocene arc-related volcanism comprises mostly andesitic and minor dacitic lava flows (Cerro de las Tórtolas Fm. The two ∼5- to 6-km-wide quasicircular depressions highlighted in Figs. (B) Example of many of the pit structures and depressions and faults (black arrow) along the eastern flank of Ascraeus Mons in Tharsis (252.72°E, 11.84°N) (CTX image F09_039302_1918). Features associated with compressional tectonics are: Reverse (or thrust) faults. (1993) who attributed the 208Pb/204Pb composition of Miocene arc-related rocks from Precordillera due to the interaction of asthenospheric wedge magmas with a Greenville-aged basement, considered to be the southern extension of the Appalachian system as part of the exotic Cuyania terrane (Ramos, 2010b and reference there in). Figure 1: Old school, not cool. Changes in arc magmatism are particularly conspicuous from middle to late Miocene, linked to the progress of the shallowing of the Nazca plate beneath the South American plate (Kay et al., 1991; Kay and Mpodozis, 2002; Yañez et al., 2001; 2002). (A) 87Sr/86Sr ratios for arc-related volcanic rocks from southern Central (Pampean and Payenia segments) and North Patagonian Andes that reflects contribution of crustal components in arc magmas through time. However, other processes, such as mantle hydration and the combination of trenchward motion of thick cratonic lithosphere and trench retreat, are also ascribed as the cause of the flat-slab setting (Manea et al., 2012; Skinner and Clayton, 2013). Extensional Tectonics. Red Sea) 'v' 1000km Fig. 7 of Powell, C.M., 1989. Palynological evidence is lacking to prove the nature of the Ordovician-Silurian contact, but Grignani claimed that deposition of the Tanzuft Formation began in this area during the late Ordovician. Figure 9.11. The Campania Plain, an E-W elongated basin infilled by up to 3000 m of Pleistocene volcaniclastic and alluvial sediments (Milia and Torrente, 1999), is part of this extensional system, which encompasses an area extending from southern Tuscany to the northern margin of Calabria. (D) Portion of the Thermal Emission Imaging System daytime global mosaic showing an unnamed crater east of Maunder crater with an elongated, irregular trough associated with a system of graben (black arrows) that transect the crater and its interior deposits (3.76°E, 50.06°S). (2003) established syn-exhumational heating of orogenic lower crust (conductive heating from the asthenosphere) and mid-crustal granulite facies metamorphism at a very high-T/P ratio (~ 1800 °C/GPa) of the crustal carapace above the Ronda lithospheric mantle peridotite, Spain. Carbonate deposition began in the early Miocene (late Cycle III) and continued until the present-day in deeper water areas away from siliclastic sedimentation. Therefore, it is often difficult to decouple metamorphism during rift-tectonics alone from an overall convergent plate boundary process. Despite main arc and eastern arc-related rocks showing similar geochemical features, some differences were described, associated with the variable composition of the continental crust assimilated by ascending magma melts (e.g., higher Sr and Ba content and lower Rb and Th concentrations in retroarc lavas at Western Precordillera; Poma et al., 2017). Indeed it has probably remained emergent throughout the entire Phanerozoic. Want to add an example to this list? It seems reasonable to assume that the smaller magnitude unconformities were also generated by crustal movements driven by plate tectonic interactions. Middle to Late Miocene carbonates developed upon the horsts. LINEAMENTS AND EXTENSIONAL TECTONICS : EXAMPLES FROM SHABA (ZAIRE) AND NE ZAMBIA by J. DEHANDSCHUTTER and J. LAVREAU (*) ABSTRACT - Fracture and lineament analysis on Landsat imagery of the Shaba­ Northern Zambia region reveals a remarkable persistancy of trends over both cratonic areas and mobile belts. This correlates with an increase in 86Sr/87Sr ratios (Fig. (CTX image B11_013786_1729.) In some instances they host elvans and "mainstage" magmatic-hydrothermal lodes (more rarely lamprophyres). 9.11). Vanesa D. Litvak, ... Andrés Folguera, in Andean Tectonics, 2019. Central Luconia Province. From the Cambridge English Corpus Extensional tectonics played a major role during the latest stages of exhumation, as shown by collapse folds and brittle shear zones. See Fig. Major subsidence occurred accompanied by rifting, and thick Nubian Sandstones were deposited, particularly in the southern part of the basin. 146, 439–446. They illustrate the tectonic evolution of the upper plate, through the reconstruction of structural maps. The title Extensional Tectonics of Central-Northern Mexico reflects a fraction of studies on Mexican country, which are summed up in a research sponsored by the Ministry of Education and the National Council for Science and Technology and identified with number 167638. Two notable examples of magmatic flare‐ups in the geological record include (1) the Sierra Nevada batholith of western North America, where despite a >100 My history of subduction, magmatism was dominated by two pulses, each lasting only 10–20 Myr [ Ducea, 2001; Van Buer and Miller, 2010 ], and (2) episodic Miocene to Recent mafic volcanism in the Andean Puna … (A) Depression in Syria Planum (212.72°E, 8.45°S), a long-lived volcanic and tectonic region in central Tharsis. Such maps do not display the evolution of the subducting lithosphere, although the tectonic reconstruction allows determination of the polarity of the subduction and its convergence direction. Wrench faults. rifts, places where extensional deformation ceased 382 Rifting, Seafloor Spreading, and Extensional Tectonics 16.1 Introduction 382 16.2 Cross-Sectional Structure of a Rift 385 16.2.1 Normal Fault Systems 385 16.2.2 Pure-Shear versus Simple-Shear Models of Rifting 389 16.2.3 Examples of Rift Structure in Cross Section 389 West Anatolia, together with the Aegean Sea and the easternmost part of Europe, is one of the best examples of continental extensional tectonics. This evidence includes the shape, orientation, and alignment of some of these features that demonstrate an element of structural control in their formation. A second footwall shortcut fault in the hanging wall of the Johnston Thrust and footwall of the Benton Fault (Flt X) was originally developed during extension on the Benton Fault and was subsequently passively carried by the Johnston Thrust and thus was not inverted. The peak of carbonate deposition was in Cycles IV and V. Strontium isotopic dating has been carried out to determine the carbonate stratigraphy. Upper: Schematic NNW–SSE cross section across the Central Luconia Province and the Balingian Province. There is no palynological evidence for the presence of late Silurian or Lochkovian rocks, and deposition in the Devonian began in the Pragian and continued until the Visean. (1989), Schettino and Turco (2006, 2009; 2011), Argnani (2012), Turco et al. This is in marked contrast to the Murzuq Basin in which was tectonism was very active particularly during the Devonian.12. The characteristics of these unconformities leave no doubt as to their tectonic origin (Embry, 1990, 1993b, 1997; Beauchamp et al., 2001; Embry et al., in press). 3 Whipple Mountains. The first type comprises low angle (dip <45°) extensional faults which exhibit listric or ramp and flat geometries and may display complex arrangements of secondary faults and folds in their hangingwalls. Active syn- to postorogenic extension during the Early and Late Devonian, south of the main Caledonian uplift, controlled the deposition of a significant terrestrial syn-extensional sequence (Old Red Sandstone), which thickens towards the basin-bounding extensional faults noted above (Powell, 1989). This area, however, contains only seven additional craters D ≥ 1 km that are interpreted to be impact craters due to their circularity and raised rims. Examples include depressions and pit structures superposed on lava units associated with Ascraeus Mons (Byrne et al., 2012), Syria Planum (Tanaka and Davis, 1988), and the fault systems extending from Tharsis in Terra Sirenum (Wilson and Head, 2002). A new Coniacian–early Santonian extensional salt tectonics event has been identified in the Cotiella thrust sheet of the central Spanish Pyrenees. Using the map from Spencer et. 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