Triassic volcanism in the Eastern Fore-Caucasus: evolution and geodynamic interpretation

Тихомиров, П. Л.; Chalot-Prat, F.; Nazarevich, B.P.

doi:10.1016/j.tecto.2003.10.014

Cited by 27 publications

(15 citation statements)

References 4 publications

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“…The extent and age of Cimmerian orogenic phases, in Late Triassic or Early Jurassic, Mid-Jurassic and Late Jurassic times, as well as the successive rifting events, are not confidently known (see Nikishin et al 1998a,b). region and in the northern part of the GC (Nazarevich et al 1986;Lordkipanidze et al 1989;Tikhomirov et al 2004). The geodynamic setting of such tectonics is still debated: was this a back-arc setting or not?…”

Section: A Review Of the Early Mesozoic Tectonic Evolution Of The Grementioning

confidence: 99%

The Mesozoic-Cenozoic tectonic evolution of the Greater Caucasus

Saintot

Brunet

Yakovlev

et al. 2006

Memoirs

119

139

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The Greater Caucasus (GC) fold-and-thrust belt lies on the southern deformed edge of the Scythian Platform (SP) and results from the Cenozoic structural inversion of a deep marine Mesozoic basin in response to the northward displacement of the Transcaucasus (lying south of the GC) subsequent to the Arabia-Eurasia collision. A review of existing and newly acquired data has allowed a reconstruction of the GC history through the Mesozoic and Cenozoic eras. In Permo(?)-Triassic times, rifting developed along at least the northern part of the belt. Structural inversion of the basin occurred during the Late Triassic corresponding to the Eo-Cimmerian orogeny, documented SE of the GC and probably linked to the accretion of what are now Iranian terranes along the continental margin. Renewed development of extensional basin formation in the area of the present-day GC began in Sinemurian-Pliensbachian times with rift activity encompassing the Mid-Jurassic. Rifting led to extreme thinning of the underlying continental crust by the Aalenian and concomitant extrusion of mid-ocean ridge basalt lavas. A Bathonian unconformity is observed on both sides of the basin and may either correspond to the end of active rifting and the onset of post-rift basin development or be the record of collision further south along the former Mesozoic active margin. The post-rift phase began with deposition of Late Jurassic platform-type sediments onto the margins and a flysch-like unit in its deeper part, which has transgressed the basin during the Cretaceous and Early Cenozoic. An initial phase of shortening occurred in the Late Eocene under a NE-SW compressional stress regime. A second shortening event that began in the Mid-Miocene (Sarmatian), accompanied by significant uplift of the belt, continues at present. It is related to the final collision of Arabia with Eurasia and led to the development of the present-day south-vergent GC fold-and-thrust belt. Some north-vergent retrothrusts are present in the western GC and a few more in the eastern GC, where a fan-shaped belt can be observed. The mechanisms responsible for the large-scale structure of the belt remain a matter of debate because the deep crustal structure of the GC is not well known. Some (mainly Russian) geoscientists have argued that the GC is an inverted basin squeezed between deep (near)-vertical faults representing the boundaries between the GC and the SP to the north and the GC and the Transcaucasus to the south. Another model, supported in part by the distribution of earthquake hypocentres, proposes the existence of south-vergent thrusts flattening at depth, along which the Transcaucasus plunges beneath the GC and the SP. In this model, a thick-skinned mode of deformation prevailed in the central part of the GC whereas the western and eastern parts display the attributes of thin-skinned fold-and-thrust belts, although, in general, the two styles of deformation coexist along the belt. The present-day high elevation observed only in the central part of the belt would have resulted...

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Section: A Review Of the Early Mesozoic Tectonic Evolution Of The Grementioning

confidence: 99%

The Mesozoic-Cenozoic tectonic evolution of the Greater Caucasus

Saintot

Brunet

Yakovlev

et al. 2006

Memoirs

119

139

View full text Add to dashboard Cite

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“…In fact, relationship between large negative carbon isotope excursions and tuffaceous claystone or tuffaceous limestone interlayers seems to supply evidences for the interpretations of the causes of the negative excursions. Moreover, strong volcano eruptions took place in the East Caucasus [57] , Turkey [58] and Siberia [59] during the early Triassic. In the Lower Yangtze Region, tuffaceous claystones and limestones occur in the transition of the Permo-Triassic boundary, above the Induan-Olenekian boundary and near the Mid-Lower Triassic boundary.…”

Section: Mechanics Of Carbon Isotope Excursionsmentioning

confidence: 99%

Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South China

et al. 2006

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Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South China, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13 C background values are intensively controlled by palaeogeographic environment. In general, δ 13 C values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in marine sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the InduanOlenekian boundary and the Lower Triassic-Middle Triassic boundary.The Early Triassic is a critical period in earth history. A series of events such as volcano eruptions [1,2] , sea-level fluctuations, changes in environmental conditions [3] , mass extinctions [4,5] as well as global negative carbon isotope excursions [6 -9] have been discovered in the uppermost Permian or across the Permian-Triassic boundary. Large scale sea-level rise [10][11][12] , restoration of environment conditions, recovery of ecosystem [13] , including gradual carbon isotope rise [14] occurred in the East Tethyan Ocean in the early Triassic after the mass extinction. In order to describe the features of carbon isotope evolutions in detail, construct evolutional pattern of carbon isotope compositions, discuss the controlling factors on carbon isotope evolution, three sections located on the carbonate platform, deep-water slope and in deep-water

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“…Dolerites are usually equigranular, never poikilitic, with the same mineralogical assemblage than T1 and T2. More detailed descriptions are in Tikhomirov et al (2004).…”

Section: Late Devonian Groupmentioning

confidence: 99%

“…As Rb data obtained via inductive coupled plasma-mass spectrometer (ICP-MS) or isotopic dilution (ID) differ from each other, two distinct ( 87 Sr/ 86 Sr)i ratios for each sample was calculated. The eruption times for each group are taken from McCann et al (2003) and Tikhomirov et al (2004). Nevertheless as the relative distribution of data from the three groups on the εNdi vs. ( 87 Sr/ 86 Sr)i diagram does not change depending on the used Rb value, the demonstration will be based on isotopic ratios using Rb ICP-MS values.…”

Section: Sr and Nd Isotopic Compositionsmentioning

confidence: 99%

“…• the Late Devonian Dniepr-Donets-Donbas basin (Chekunov and Naumenko 1982;Wilson and Lyashkevich 1996;McCann et al 2003); • the Triassic Eastern Fore Caucasus basin (Dubinski and Matsenko 1965;Burshtar et al 1973;Nazarevich et al 1986;Tikhomirov et al 2004); • the Jurassic Western Fore Caucasus basin ; • the Cretaceous Karkinit rift basin (western part of Scythian Platform) (Muratov 1969;Chekunov et al 1976;Grigorieva et al 1981;Leschukh 1992;Nikishin et al 1998aNikishin et al , b, 2001; • the Neogene Minvody basin (Stavropol High) (Polovinkina 1960;Adamia and Lordkipanidze 1989).…”

Section: Introductionmentioning

confidence: 99%

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