Revised stratigraphy of the Mesozoic rocks of southern Cyprus

1980 ◽  
Vol 117 (6) ◽  
pp. 547-563 ◽  
Author(s):  
R. E. Swarbrick ◽  
A. H. F. Robertson
Keyword(s):  
Oceanic Crust ◽  
Continental Margin ◽  
Late Cretaceous ◽  
Sedimentary Cover ◽  
Igneous Rocks ◽  
Late Triassic ◽  
Metamorphic Rocks ◽  
Southern Cyprus

SummaryRecent resurgence of interest in the Mesozoic rocks of SW and southern Cyprus necessitates redefinition of the Mesozoic sedimentary and igneous rocks in line with modern stratigraphical convention. Two fundamentally different rocks associations are present, the Troodos Complex, not redefined, a portion of late Cretaceous oceanic crust, and the Mamonia Complex, the tectonically dismembered remnants of a Mesozoic continental margin. Based on earlier work, the Mamonia Complex is divided into two groups, each subdivided into a number of subsidiary formations and members. The Ayios Photios Group is wholly sedimentary, and records the evolution of a late Triassic to Cretaceous inactive continental margin. The Dhiarizos Group represents Triassic alkalic volcanism and sedimentation adjacent to a continental margin. Several other formations not included in the two groups comprise sedimentary mélange and metamorphic rocks. The Troodos Complex possesses an in situ late Cretaceous sedimentary cover which includes two formations of ferromanganiferous pelagic sediments, radiolarites and volcaniclastic sandstones. The overlying Cainozoic calcareous units are not redefined here.

scholarly journals Age and microfacies of oceanic Upper Triassic radiolarite components from the Middle Jurassic ophiolitic mélange in the Zlatibor Mountains (Inner Dinarides, Serbia) and their provenance

2017 ◽  
Vol 68 (4) ◽  
pp. 350-365 ◽  
Author(s):  
Hans-Jürgen Gawlick ◽  
Nevenka Djerić ◽  
Sigrid Missoni ◽  
Nikita Yu. Bragin ◽  
Richard Lein ◽  
...  
Keyword(s):  
Continental Slope ◽  
Oceanic Crust ◽  
Middle Jurassic ◽  
Sedimentary Cover ◽  
Upper Triassic ◽  
Late Triassic ◽  
Ophiolitic Mélange ◽  
Reef Limestone ◽  
Sedimentary Succession ◽  
Unit Yield

AbstractOceanic radiolarite components from the Middle Jurassic ophiolitic mélange between Trnava and Rožanstvo in the Zlatibor Mountains (Dinaridic Ophiolite Belt) west of the Drina–Ivanjica unit yield Late Triassic radiolarian ages. The microfacies characteristics of the radiolarites show pure ribbon radiolarites without crinoids or thin-shelled bivalves. Beside their age and the preservation of the radiolarians this points to a deposition of the radiolarites on top of the oceanic crust of the Neo-Tethys, which started to open in the Late Anisian. South of the study area the ophiolitic mélange (Gostilje–Ljubiš–Visoka–Radoševo mélange) contains a mixture of blocks of 1) oceanic crust, 2) Middle and Upper Triassic ribbon radiolarites, and 3) open marine limestones from the continental slope. On the basis of this composition we can conclude that the Upper Triassic radiolarite clasts derive either from 1) the younger parts of the sedimentary succession above the oceanic crust near the continental slope or, more convincingly 2) the sedimentary cover of ophiolites in a higher nappe position, because Upper Triassic ribbon radiolarites are only expected in more distal oceanic areas. The ophiolitic mélange in the study area overlies different carbonate blocks of an underlying carbonate-clastic mélange (Sirogojno mélange). We date and describe three localities with different Upper Triassic radiolarite clasts in a mélange, which occurs A) on top of Upper Triassic fore-reef to reefal limestones (Dachstein reef), B) between an Upper Triassic reefal limestone block and a Lower Carnian reef limestone (Wetterstein reef), and C) in fissures of an Upper Triassic lagoonal to back-reef limestone (Dachstein lagoon). The sedimentary features point to a sedimentary and not to a tectonic emplacement of the ophiolitic mélange (= sedimentary mélange) filling the rough topography of the topmost carbonate-clastic mélange below. The block spectrum of the underlying and slightly older carbonate-clastic mélange points to a deposition of the sedimentary ophiolitic mélange east of or on top of the Drina–Ivanjica unit.

scholarly journals Supplemental Material: Syn-exhumation magmatism in an active continental margin above a continental subduction zone: Evidence from Late Triassic mafic igneous rocks in the southeastern North China Block

2020 ◽  
Author(s):  
Wei Fang ◽  
Li-Qun Dai
Keyword(s):  
Trace Element ◽  
Subduction Zone ◽  
Continental Margin ◽  
North China ◽  
Active Continental Margin ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Late Triassic ◽  
North China Block ◽  
Pb Isotope

Table S1: Major and trace element compositions of mafic igneous rocks from the southeastern North China Block; Table S2: Whole-rock Rb-Sr, Sm-Nd, and Lu-Hf isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S3: LA-ICPMS zircon U-Pb isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S4: Zircon LA-MC-ICPMS Lu-Hf and SIMS O isotopic compositions of mafic igneous rocks from the southeastern North China Block.

Provenance and palaeogeographic implications of detrital zircons from the lower Carboniferous Riwanchaka Formation of the central Tibetan Plateau

2019 ◽  
Vol 156 (12) ◽  
pp. 2031-2042 ◽  
Author(s):  
Hu Peng ◽  
Chaoming Xie ◽  
Cai Li ◽  
Zhongyue Zhang
Keyword(s):  
High Pressure ◽  
Continental Margin ◽  
Detrital Zircon ◽  
Suture Zone ◽  
Metamorphic Rocks ◽  
Lower Carboniferous ◽  
Margin Setting ◽  
Depositional Settings ◽  
Tethys Ocean

AbstractThe Longmu Co–Shuanghu suture zone, which divides the Qiangtang terrane into the northern and southern Qiangtang blocks, is regarded as a key locality in reconstructing the evolutionary history of the Palaeo-Tethys Ocean and the break-up of Gondwana. However, although low-temperature – high-pressure metamorphic rocks and ophiolites have been documented within the Longmu Co–Shuanghu suture zone, it remains unclear whether it is an in situ suture zone and represents the relic of the main Palaeo-Tethys Ocean. The uncertainty stems mainly from the limited systematic studies of the provenance, palaeontological evidence and depositional settings of strata on either side of the Longmu Co–Shuanghu suture zone (i.e. northern and southern Qiangtang blocks). Here we report new detrital zircon U–Pb ages and palaeontological data from Lower Carboniferous strata (Riwanchaka Formation) of the northern Qiangtang block, central Tibet. The Riwanchaka Formation contains warm-climate biota with Cathaysian affinities. Provenance analysis reveals that the formation has detrital zircon spectra similar to those from strata of the Yangtze Plate, and it contains a large proportion of zircons with ages (~360 Ma) similar to the timing of synsedimentary magmatic arc activity, implying an active continental margin setting associated with northward subduction of the Palaeo-Tethyan oceanic lithosphere. Conversely, the Carboniferous–Permian strata from the southern Qiangtang block contain cool-water faunas of Gondwanan affinity and exhibit minimum zircon crystallization ages that are markedly older than their depositional ages, suggesting a passive continental margin setting. The differences in provenance, palaeontological assemblages and depositional settings of the Carboniferous to Permian strata either side of the Longmu Co–Shuanghu suture zone indicate the existence of an ancient ocean between the northern and southern Qiangtang blocks. Combining the new findings with previous studies on high-pressure metamorphic rocks, arc magmatism and ophiolites, we support the interpretation that the Longmu Co–Shuanghu suture zone is an in situ suture zone that represents the main suture of the Palaeo-Tethys Ocean.

Pre-Quaternary landscape evolution in the Scottish Highlands

1991 ◽  
Vol 82 (1) ◽  
pp. 1-26 ◽  
Author(s):  
A. M. Hall
Keyword(s):  
Late Cretaceous ◽  
Late Jurassic ◽  
Landscape Evolution ◽  
Igneous Rocks ◽  
Late Triassic ◽  
Progressive Reduction ◽  
Near Surface ◽  
Scottish Highlands ◽  
Early Tertiary ◽  
Relief Elements

ABSTRACTThe development of the relief of the Scottish Highlands is traced over the last 400 Ma. Evidence from Late Palaeozoic and Mesozoic sediments and near-surface volcanic and igneous rocks shows that post-Devonian erosion of basement has been < 1–2 km and that the main morphotectonic units of the Highlands were already established by the end of the Palaeozoic. During the Mesozoic, the Highlands experienced several major erosional cycles, beginning with uplift, reactivation of relief and stripping of cover rocks, followed by progressive reduction of relief through etchplanation and culminating in extensive marine transgressions in the Late Triassic, Late Jurassic and Late Cretaceous. In the Early Tertiary major uplift affected the Highlands, with downwarping and block movements along basin margins, but levels of uplift and denudation around the Tertiary igneous centres cannot be extrapolated to other areas. Buchan and Caithness remained relatively stable and Mesozoic relief elements were maintained during gradual surface lowering. Earth movements of lesser magnitude continued episodically until at least the end of the Tertiary. After 50 Ma the Highland terrain evolved by dynamic etching, with deep weathering of varied geology under warm to temperate humid environments leading to a progressive differentiation of relief, with formation of basins, valleys, scarps and inselbergs often closely adjusted to lithostructural controls.

scholarly journals Supplemental Material: Syn-exhumation magmatism in an active continental margin above a continental subduction zone: Evidence from Late Triassic mafic igneous rocks in the southeastern North China Block

2020 ◽  
Author(s):  
Wei Fang ◽  
Li-Qun Dai
Keyword(s):  
Trace Element ◽  
Subduction Zone ◽  
Continental Margin ◽  
North China ◽  
Active Continental Margin ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Late Triassic ◽  
North China Block ◽  
Pb Isotope

Table S1: Major and trace element compositions of mafic igneous rocks from the southeastern North China Block; Table S2: Whole-rock Rb-Sr, Sm-Nd, and Lu-Hf isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S3: LA-ICPMS zircon U-Pb isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S4: Zircon LA-MC-ICPMS Lu-Hf and SIMS O isotopic compositions of mafic igneous rocks from the southeastern North China Block.

Korotaikha Composite Tectono-Sedimentary Element

2021 ◽  
pp. M57-2018-28
Author(s):  
Konstantin Sobornov
Keyword(s):  
Continental Margin ◽  
Sedimentary Cover ◽  
Systems Development ◽  
Late Triassic ◽  
Word Class ◽  
Late Permian ◽  
Upper Ordovician ◽  
Petroleum Systems ◽  
Thrust Sheets ◽  
Uplift And Erosion

AbstractKorotaikha Composite Tectono-Sedimentary Element constitutes the northeastern part of the Timan-Pechora petroleum province. It is evolved through rifting, continental margin development, and two-stage collisional phase related to the Uralian Orogeny in the Late Artinskian-Late Permian and the Pay-Khoy Orogeny in the Late Triassic. In course of the later one, the sedimentary cover was delaminated along the Upper Ordovician evaporites which produced general uplift. The complex tectonostratigraphic history resulted in accumulation of up to 15 km-thick sedimentary section which has all essential ingredients of prolific petroleum systems, including the word-class Domanik source rock, and a large variety of structural and stratigraphic traps. Nevertheless, up to now, no commercial discoveries have been made yet. A review of geological setting and petroleum habitat suggests that the petroleum systems development was more complex than it was assumed previously. The amount of uplift and erosion related to the updip displacement on the salt detachment was underestimated. Reinterpretation of the available data shows the presence of large untested exploration opportunities including duplex thrust sheets and subsalt structures related to squeezed diapirs.

Some observations on the use of zircon U-Pb geochronology in the study of granitic rocks

1992 ◽  
Vol 83 (1-2) ◽  
pp. 447-458 ◽  
Author(s):  
Ian S. Williams
Keyword(s):  
Igneous Rocks ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Ion Microprobe ◽  
Zircon Population ◽  
Metamorphic History ◽  
Ion Probe ◽  
Isotopic Analyses ◽  
Single Zircon

ABSTRACTIn situ, microscale, U-Pb isotopic analyses of zircon using the SHRIMP ion microprobe demonstrate both the potential and the limitations of zircon U-Pb geochronology. Most zircons, whether from igneous or metamorphic rocks, need to be considered as mixed isotopic systems. In simple, young igneous rocks the mixing is principally between isotopically disturbed and undisturbed zircon. In polymetamorphic rocks, several generations of zircon growth can coexist, each with a different pattern of discordance. A similar situation exists for igneous rocks rich in inherited zircon, as these contain both melt-precipitated zircon and inherited components of several different ages. Microscale analysis by ion probe makes it possible to sample the record of provenance, age and metamorphic history commonly preserved within a single zircon population. It also indicates how the interpretation of conventionallymeasured bulk zircon isotopic compositions might be improved.

Syn-exhumation magmatism in an active continental margin above a continental subduction zone: Evidence from Late Triassic mafic igneous rocks in the southeastern North China Block

2020 ◽  
Author(s):  
Wei Fang ◽  
Li-Qun Dai ◽  
Yong-Fei Zheng ◽  
Zi-Fu Zhao ◽  
Qi Chen ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Continental Margin ◽  
North China ◽  
Mantle Wedge ◽  
Active Continental Margin ◽  
Continental Collision ◽  
Igneous Rocks ◽  
Late Triassic ◽  
North China Block ◽  
Continental Subduction

Syn-subduction arc magmatism is absent above continental subduction zones, providing important constraints on the nature of petrogenetic processes during continental collision. Nevertheless, we have identified syn-exhumation mafic igneous rocks in an active continental margin above a continental subduction zone, where the South China Block (SCB) was deeply subducted beneath the North China Block (NCB) for collisional orogeny in the Triassic. These mafic igneous rocks occur in the southeastern margin of the NCB, showing consistent Late Triassic zircon U-Pb ages of ca. 219−218 Ma, coeval with exhumation of the deeply subducted continental crust. These rocks are categorized into two series of sub-alkaline and alkaline, all exhibiting arc-like trace element distribution patterns, highly enriched radiogenic Sr-Nd-Hf and high zircon O isotope compositions. In particular, they exhibit two-stage whole-rock Nd and Hf model ages and zircon Hf model ages of Paleoproterozoic, which are comparable to those of ultrahigh-pressure metamorphic rocks with the SCB affinity in the Dabie-Sulu orogenic belt. Such geochemical features indicate that these mafic igneous rocks were derived from partial melting of ultramafic metasomatites generated by reaction of felsic melts from the subducted SCB with the mantle wedge peridotite beneath the NCB. The geochemical differences in element and isotope compositions between the two series igneous rocks can be mainly ascribed to different proportions of the crustal component in the metasomatites, which is verified by quantitative modellings of the geochemical transfer in the continental subduction zone. The systematic variations in some geochemical variables such as Fe/Mn, Zn/Fe, and Nb/Ta ratios indicate pyroxenite-rich and hornblendite-rich lithologies, respectively, for the sub-alkaline and alkaline series igneous rocks. With the tectonic extension for exhumation of the deeply subducted continental crust in the Late Triassic, the fertile and enriched metasomatites in the mantle wedge underwent partial melting for the syn-exhumation mafic magmatism in the southeastern NCB. Therefore, the mafic igneous rocks in the active continental margin not only record the crust-mantle interaction in the continental subduction zone, but also witness the generation of syn-exhumation magmatism in the late stage of continental collision.

The Canadian Cordillera, the Hellenides, and the Sea-Floor Spreading Theory

1972 ◽  
Vol 9 (6) ◽  
pp. 709-743 ◽  
Author(s):  
Jean Dercourt
Keyword(s):  
Pacific Ocean ◽  
Oceanic Crust ◽  
Continental Margin ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Late Triassic ◽  
Canadian Cordillera ◽  
Transform Faults ◽  
Sea Floor ◽  
Sea Floor Spreading

The theory of plate tectonics is applied to the tectonic evolution of the Hellenides and the Canadian Cordillera. In the Hellenides a Tethyan zone of sea-floor spreading developed within the continental crust during Triassic time and functioned until the end of the Middle Jurassic. It led to the formation of two plates, each with continental and oceanic segments, that were separated in some places by accreting plate margins and in others by transform faults. In Late Jurassic time the mid-Tethyan ridge became inactive as new ridges developed in the Atlantic Ocean. From Late Jurassic to Recent time, Tethyan oceanic crust largely disappeared under one of the cratons. The chronology of tectonic events in the Hellenides corresponds well with that of sea-floor spreading in the Atlantic.Four periods of sea-floor spreading were involved in the formation of the Canadian Cordillera: (1) a Silurian? to Early Devonian period when an Archeo-Pacific Ocean separated the Canadian craton with a stable sedimentary margin from a volcanic archipelago; (2) a Middle Devonian to Permian period when the extinct volcanic archipelago was bounded to the west by a spreading Paleo-Pacific Ocean, and to the east by a tectonic contact which was consuming Archeo-Pacific oceanic crust; part of this crust was obducted over the continental margin; (3) a Late Triassic to Middle Jurassic period when a second volcanic archipelago separated a spreading Neo-Pacific Ocean from the continental margin; and (4) a Late Jurassic to Recent period where spreading occurred in both the Atlantic and Pacific Oceans, subjecting the second volcanic archipelago and the continental margin to major tectonism; since the Paleocene, the Cordillera has slid towards the NNW along transform faults.

scholarly journals Geological and seismic evidence for the tectonic volution of the NE Oman continental margin and Gulf of Oman

Geosphere ◽  
2021 ◽  
Author(s):  
Bruce Levell ◽  
Michael Searle ◽  
Adrian White ◽  
Lauren Kedar ◽  
Henk Droste ◽  
...  
Keyword(s):  
Continental Margin ◽  
Late Cretaceous ◽  
Deep Water ◽  
Large Scale ◽  
Accretionary Prism ◽  
Oceanic Lithosphere ◽  
Seismic Reflection Data ◽  
Gulf Of Oman ◽  
Semail Ophiolite

Late Cretaceous obduction of the Semail ophiolite and underlying thrust sheets of Neo-Tethyan oceanic sediments onto the submerged continental margin of Oman involved thin-skinned SW-vergent thrusting above a thick Guadalupian–Cenomanian shelf-carbonate sequence. A flexural foreland basin (Muti and Aruma Basin) developed due to the thrust loading. Newly available seismic reflection data, tied to wells in the Gulf of Oman, suggest indirectly that the trailing edge of the Semail Ophiolite is not rooted in the Gulf of Oman crust but is truncated by an ENE-dipping extensional fault parallel to the coastline. This fault is inferred to separate the Semail ophiolite to the SW from in situ oceanic Gulf of Oman crust to the NE. It forms the basin margin to a “hinterland” basin formed atop the Gulf of Oman crust, in which 5 km of Late Cretaceous deep-water mudstones accumulated together with 4 km of Miocene and younger deep-water mudstones and sandstones. Syndepositional folding included Paleocene–Eocene folds on N-S axes, and Paleocene to Oligocene growth faults with roll-over anticlines, along the basin flank. Pliocene compression formed, or tightened, box folds whose axes parallel the modern coast with local south-vergent thrusts and reversal of the growth faults. This Pliocene compression resulted in large-scale buckling of the Cenozoic section, truncated above by an intra-Pliocene unconformity. A spectacular 60-km-long, Eocene(?) to Recent, low-angle, extensional, gravitational fault, down-throws the upper basin fill to the north. The inferred basement of the hinterland basin is in situ Late Cretaceous oceanic lithosphere that is subducting northwards beneath the Makran accretionary prism.

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