scholarly journals Evolution of the Late Mesozoic Magmatism of the Omulevka Terrane of the North Part of the Verkhoyansk–Kolyma Orogenic Region

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1208
Author(s):  
Vera A. Trunilina
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Active Continental Margin ◽  
Alkali Feldspar ◽  
Research Area ◽  
Total Alkalinity ◽  
Late Mesozoic ◽  
The North ◽  
Intrusive Rocks ◽  
North Part

This article presents the results of a study of Late Mesozoic intrusive formations of the Omulevka terrane of the Verkhoyansk–Kolyma orogenic region. The research area covers the Selennyakh block of the Omulevka terrane and the territory adjacent to the south. The compositions of rock-forming, accessory and restitic minerals and geochemical features of intrusive rocks are considered. The methods of optical microscopy, microprobe, silicate and spectral analyses were used. There are the following several stages in the evolution of magmatism: (1) the Late Jurassic supra-subduction (gabbro, dolerites), (2) the beginning of the Early Cretaceous-transitional from supra-subduction to marginal-continental (gabbro-diorites, diorites, granodiorites), (3) the Early Cretaceous of active continental margin (granodiorites, granites), (4) the Late Cretaceous postorogenic or continental-riftogenic (alkali-feldspar granites of A-type), (5) the Late Cretaceous continental riftogenic (subalkaline gabbroids and basaltoids). In the process of evolution from stage one to stage four, there was an increase in the silicic acid content, total alkalinity and ferruginousity of rocks with the movement of magmogeneration levels to higher and higher horizons of the lithosphere (calculated pressure from 1.6–1.4 GPa to 0.6–0.9 GPa). At the same time, the preservation of high temperatures of magmogeneration (1000–1150 °C) and crystallization implies the supply of additional heat from an external (deep) source during the formation of granitoid melts. The magmatic activity is completed by the intrusion of subalkaline derivatives of a deep hearth, formed by metasomatized lherzolites. All the studied igneous rocks are either direct mantle fusions, or bear signs of the participation of mantle matter in the generation of parent melts in crustal substrates: the presence of tschermakite in gabbroids, nonequilibrium structures, the composition of early generations of biotites corresponding to biotites of mantle and crust-mantle derivatives, the presence of pyroxenes and accessory minerals characteristic of mantle magmas in granitoids. In the diagram Al-Na-K-2Ca–Fe + Ti + Mg, the composition points of the studied intrusive rocks tend to the mixing trend. In general, the research results suggest that the evolution of the Late Mesozoic intrusive magmatism of the studied territory and the specific matter of rock compositions were caused by the crust-mantle interaction as a result of the rise of mantle diapirs in the crust from a long-existing deep hearth of the main melt.

scholarly journals Geochemical Evidence for Thickening and Thinning of Lower Crust beneath the Jiaodong Peninsula: Implications for Late Mesozoic Destruction of the Eastern North China Craton

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
YaYun Liang ◽  
Wenhui Guo ◽  
Yao Ma ◽  
Enquan Zhao
Keyword(s):  
Continental Crust ◽  
Early Cretaceous ◽  
North China Craton ◽  
Late Jurassic ◽  
North China ◽  
Temporal Variations ◽  
Late Mesozoic ◽  
Jiaodong Peninsula ◽  
Intrusive Rocks ◽  
Subducting Slab

Abstract The eastern North China Craton (NCC) has been recognised as undergoing cratonic destruction during the Mesozoic; however, the mechanism of its destruction is still unclear. The main difference between the proposed models is whether the lower continental crust (LCC) underwent thinning. In this study, we conducted comprehensive analyses of Late Mesozoic felsic intrusive rocks, including Late Jurassic granites (166–146 Ma), Early Cretaceous granodiorites (136–123 Ma), and latest Early Cretaceous granites (123–108 Ma) from the Jiaodong Peninsula, located on the southeastern margin of the NCC. These rocks allowed us to investigate variations in the LCC thickness in this region and to further discuss the destruction mechanism of the eastern NCC. Here, temporal variations in crustal thickness can be tracked using whole-rock La/Yb ratios of the felsic intrusive rocks. Our study shows that the continental crust in the eastern NCC thickened during the Late Jurassic (>40 km) due to compression and the westward subduction of the Palaeo-Pacific Ocean lithosphere beneath the NCC since the Early Jurassic. The continental crust further thickened during the Early Cretaceous, caused by the steepening of the subducting slab after ~144 Ma that produced crustal underplating of mantle-derived melts in an extensional setting. However, the continental crust thinned (20–40 km) during the latest Early Cretaceous, caused by the rollback of the subducting slab after ~123 Ma. The geochemical compositions of three stages of felsic intrusions also suggest that the regional tectonic stress that affects the eastern NCC altered from a compressional to an intraplate extensional environment after ~144 Ma. Thus, the Late Mesozoic destruction of the eastern NCC and its accompanying magmatism were controlled by prolonged thermomechanical-chemical erosion due to low-angle subduction, steepening, and rollback of the Palaeo-Pacific Oceanic lithosphere.

Contrasting Middle Jurassic and Early Cretaceous mafic intrusive rocks from western Liaoning, North China craton: petrogenesis and tectonic implications

2010 ◽  
Vol 147 (6) ◽  
pp. 844-859 ◽  
Author(s):  
XIAOHUI ZHANG ◽  
HONGFU ZHANG ◽  
NENG JIANG ◽  
SIMON A. WILDE
Keyword(s):  
Trace Element ◽  
Early Cretaceous ◽  
North China Craton ◽  
Middle Jurassic ◽  
North China ◽  
Stability Field ◽  
Rock Interaction ◽  
Western Liaoning ◽  
Late Mesozoic ◽  
Intrusive Rocks

AbstractZircon U–Pb dating, whole-rock major oxide, trace element and Sr–Nd isotopic data are presented for the Late Mesozoic mafic intrusive rocks from Yiwulüshan of western Liaoning along the eastern segment of the Yanshan belt, North China craton, with two episodes of magmatism documented. Middle Jurassic hornblende-rich gabbros show enrichment of large ion lithophile elements and light REE, and prominent depletion in high field strength elements, and possess moderately enriched isotopic compositions with (87Sr/86Sr)i ranging from 0.7056 to 0.7065 and ɛNd(t) from −5.0 to −7.1. These features suggest that the gabbros were derived from an amphibole-bearing harzburgitic lithospheric mantle source metasomatized recently by slab-derived fluids. By contrast, Early Cretaceous mafic dykes are gabbroic dioritic to dioritic in composition, with comparable trace element characteristics to continental crust and depleted isotopic signatures ((87Sr/86Sr)i = 0.7048–0.7055, ɛNd(t) = 0 to −3.0). They probably originated from partial melting of a relatively fertile asthenospheric mantle in the spinel stability field, with subsequent lower crustal assimilation and fractional crystallization. These two contrasting mafic intrusive suites, together with multiple Mesozoic mafic volcanic rocks from western Liaoning, documented a localized lithospheric thinning process, mainly through prolonged hydro-weakening or melt–rock interaction and triggered by gravitational collapse, possibly within an evolved post-collisional to within-plate extensional regime.

scholarly journals The Mesozoic Tectonic Dynamics and Chronology in the Eastern North China Block

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Quanlin Hou ◽  
Qing Liu ◽  
Hongyuan Zhang ◽  
Xiaohui Zhang ◽  
Jun Li
Keyword(s):  
North China ◽  
Late Triassic ◽  
Upper Crust ◽  
North China Block ◽  
Late Mesozoic ◽  
Detachment Faults ◽  
The North ◽  
North Part ◽  
Strong Compression ◽  
Tectonic System

Mesozoic tectonic events in different areas of the eastern North China Block (NCB) show consistency in tectonic time and genesis. The Triassic collision between NCB and Yangtze results in the nearly S-N strong compression in the Dabie, Jiaodong, and west Shandong areas in Middle Triassic-Middle Jurassic. Compression in the Yanshan area in the north part of NCB was mainly affected by the collision between Mongolia Block and NCB, as well as Siberia Block and North China-Mongolia Block in Late Triassic-Late Jurassic. However, in the eastern NCB, compressive tectonic system in Early Mesozoic was inversed into extensional tectonic system in Late Mesozoic. The extension in Late Mesozoic at upper crust mainly exhibits as extensional detachment faults and metamorphic core complex (MCC). The deformation age of extensional detachment faults is peaking at 120–110 Ma in Yanshan area and at 130–110 Ma in the Dabie area. In the Jiaodong area eastern to the Tan-Lu faults, the compression thrust had been continuing to Late Mesozoic at least in upper crust related to the sinistral strike slipping of the Tan-Lu fault zone.The extensional detachments in the eastern NCB would be caused by strong crust-mantle action with upwelling mantle in Late Mesozoic.

scholarly journals Early Cretaceous

1982 ◽  
Vol 8 ◽  
pp. 45-49
Author(s):  
Jens Morgen Hansen ◽  
Arne Buch
Keyword(s):  
North Sea ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Late Jurassic ◽  
Significant Feature ◽  
Marine Clay ◽  
The North ◽  
Marine Sand ◽  
The North Sea ◽  
Early Late

The Early Cretaceous sea primarily covered the same basinal regions as the Late Jurassic sea but, late in the Early Cretaceous the sea also covered Late Jurassic land masses. During Early Cretaceous time the topography of the North Sea region became gradually buried. The following major transgression comprises the transition Early/Late Cretaceous. At the Jurassic/ Cretaceous transition, the Late Cimmerian unconformity is a significant feature (fig. 24), known from large parts of the North Sea region. The subsequent transgression and sedimentation of marine clay (the Valhall Formation), and marine sand (the LC-1 Unit), started late in Late Jurassic. Therefore, the formations described in the present chapter also comprise sediments of Late Jurassic age. Thicknesses of the Lower Cretaceous sediments are given in fig. 15.

THE NORTH PAARATTE GAS DISCOVERY

1981 ◽  
Vol 21 (1) ◽  
pp. 78
Author(s):  
I. McPhee ◽  
M. D. McNicol ◽  
D. M. Harrison
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Gas Flows ◽  
Production Testing ◽  
Seismic Surveys ◽  
The Past ◽  
The North ◽  
Broken Hill ◽  
Probable Source ◽  
Structural Closure

The North Paaratte 1 gas discovery well was drilled, in November 1979, on the Port Campbell High in the Otway Basin to test a discrete structural closure 3.5 km from the Frome-Broken Hill Port Campbell 1 well, which discovered gas in non-commercial quantities in 1959. A number of other minor gas flows have been encountered in wells drilled since 1959 in the vicinity, but none have beeen commercial.A rate of flow of 9.6 MMcf/D was substained on production testing of the North Paaratte discovery well. This is the first discovery to have possible commercial significance in the Otway Basin, which has attracted a moderate level of exploration effort for the past 25 years.The gas at North Paaratte is reservoired in the Waarre Sandstone of earliest Late Cretaceous age; the probable source of the gas being the underlying Early Cretaceous Otway Group. The structure relies on faulting for closure and is sealed by the Belfast Mudstone, which drapes over the fault block.Post-drill seismic surveys were carried out to map the area of closure and a step-out well to determine the extent of the gas reserve is programmed for early 1981.

scholarly journals The significance of a Middle Devonian Kl Ar age of an intrusive rock in the southern part of the North Greenland Fold Belt

1983 ◽  
Vol 31 ◽  
pp. 121-127
Author(s):  
Stig A. Schack Pedersen ◽  
Paul Martin Holm
Keyword(s):  
Late Cretaceous ◽  
Middle Devonian ◽  
The Arctic ◽  
Intrusive Body ◽  
Fold Belt ◽  
The North ◽  
Intrusive Rocks ◽  
Deformation Event ◽  
Dyke Swarms ◽  
North Greenland

A Kl Ar age of 380 ± 5 Ma has been obtained from an intrusive body in the· southern part of the North Greenland Fold Belt in Peary Land. This age dates the first major deformation event in the North Greenland Fold Belt, and it is inferred that a correlation exists between the North Greenland Fold Belt and the Northern Ellesmerian Fold Complex of the Arctic Canadian archipelago. The dating furthermore casts serious doubt on the proposed genetic link between the intrusive rocks of the southern part of the North Greenland Fold Belt and the Late Cretaceous Kap Washington volcanics and the N-S trending dyke swarms W of Peary Land.

Petrogenesis and tectonic implications of A-type granites in the Dabie orogenic belt, China: geochronological and geochemical constraints

2009 ◽  
Vol 146 (5) ◽  
pp. 638-651 ◽  
Author(s):  
LING CHEN ◽  
CHANG-QIAN MA ◽  
ZHEN-BING SHE ◽  
ROGER MASON ◽  
JIN-YANG ZHANG ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Eastern China ◽  
Volcanic Rocks ◽  
Orogenic Belt ◽  
The Body ◽  
Geochemical Data ◽  
Late Mesozoic ◽  
The North ◽  
Dabie Orogenic Belt ◽  
Type Granite

AbstractThe Dabie orogenic belt is characterized by the presence of large volumes of intrusive and volcanic rocks that formed in Late Mesozoic times. Most of the intrusive bodies are I-type granites but it is still unclear whether there are contemporary A-type granites. Here, we report the first unambiguous discovery of A-type granite from Baiyashan in the North Dabie tectonic belt. The crystallization age of the body has been fixed as 120.4 ± 1.2 Ma using U–Pb analysis of zircons by LA-ICPMS. The Baiyashan granite is enriched in Si, K, Na, Rb and REE, has elevated FeOtot/(FeOtot + MgO) and Ga/Al ratios, and is depleted in Mg, Ca, Mn, Ba, Sr, P and Ti. The REE composition shows highly fractionated patterns with (La/Yb)N = 6.95–16.68 and Eu*/Eu = 0.33–0.59. Its crystallization age, field relationships, petrographic and geochemical data show beyond doubt that the Baiyashan granite is an Early Cretaceous A-type granite. Sr–Nd isotope systematics are characterized by a high ISr of 0.708–0.714 and a low ɛNd of −7.5 to −19.4, with TDM2 = 1.5–2.5 Ga, and these data indicate that the magmas were dominantly sourced from partial melting of middle to lower crustal intermediate-felsic igneous rocks and mingling with mafic to intermediate magmas, during rift-related magmatism associated with subduction of the Palaeo-Pacific Plate beneath Eastern China in Early Cretaceous times.

Geochronological constraints on magmatism and polyphase deformation and metamorphism in the southern Omineca Belt, British Columbia

2017 ◽  
Vol 54 (5) ◽  
pp. 529-549 ◽  
Author(s):  
Ewan Russell Webster ◽  
David Pattison ◽  
S. Andrew DuFrane
Keyword(s):  
British Columbia ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Middle Jurassic ◽  
Inductively Coupled Plasma ◽  
Contact Aureole ◽  
Inductively Coupled ◽  
The North ◽  
Three Samples ◽  
Geochronological Constraints

The Omineca Belt between Nelson and Creston in southeastern British Columbia was affected by overlapping pulses of Mesozoic magmatism, metamorphism, and deformation. U–Pb geochronological data from zircon and monazite were collected by laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) to constrain the timing of these events. The Porcupine Creek stock (162.3 ± 1.3 Ma) intruded across folds and fabrics associated with the earliest phase of regional deformation and metamorphism (D1M1), restricting it to the Early–Middle Jurassic. The Jurassic structures are overprinted northwards by Early Cretaceous deformation and metamorphism (D2M2). The Baldy pluton (117.8 ± 1.2 Ma) crosscuts the regional 144–134 Ma M2 isograds, yet was pervasively affected by the D2 deformation, indicating that D2 deformation outlasted M2 metamorphism but had ceased by 111 Ma, the age of an undeformed pluton. Monazite dates from a kyanite-bearing rock in the contact aureole of the Middle Jurassic Wall stock overlap with the age of the intrusion (167 Ma), indicating a contact rather than regional origin for the kyanite. In the southeast part of the study area, three samples from the regional sillimanite zone contain monazite intergrown with sillimanite that yield dates between 80 and 69 Ma, indicating an episode of Late Cretaceous (M3) Barrovian metamorphism and deformation (D3). To the north of this domain, in an area characterized by the older D2M2 deformation, a sillimanite zone schist contains two main monazite age populations, suggestive of overlapping effects of Early Cretaceous and Late Cretaceous metamorphic episodes.

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