Lower Paleozoic Rocks, western Part of the North Greenland Fold Belt

1967 ◽  
Author(s):  
P R Dawes
1981 ◽  
Vol 106 ◽  
pp. 69-75
Author(s):  
I Parsons

A series of smal! volcanic centres cut Ordovician turbidites of Formation A in the southem part of Johannes V. Jensen Land between Midtkap and Frigg Fjord (Map 2). Their general location and main rock types were described by Soper et al. (1980) and their nomenclature is adopted here for fig. 22 with the addition of the small pipe B2. A further small intrusion, south-west of Frigg Fjord, was described by Pedersen (1980). The centres lie 5-10 km south of, and parallel to, the important Harder Fjord fault zone (fig. 22) which traverses the southern part of the North Greenland fold belt and shows substantial downthrow to the south (Higgins et al., this report).


2018 ◽  
Vol 55 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dominik Letsch ◽  
Mohamed El Houicha ◽  
Albrecht von Quadt ◽  
Wilfried Winkler

This article provides stratigraphic and geochronological data from a central part of Gondwana’s northern margin — the Moroccan Meseta Domain. This region, located to the north of the Anti-Atlas area with extensive outcrops of Precambrian and lower Paleozoic rocks, has hitherto not received much attention with regard to its Precambrian geology. Detrital and volcanic zircon ages have been used to constrain sedimentary depositional ages and crustal affinities of sedimentary source rocks in stratigraphic key sections. Based on this, a four-step paleotectonic evolution of the Meseta Domain from the Ediacaran until the Early Ordovician is proposed. This evolution documents the transition from a terrestrial volcanic setting during the Ediacaran to a short-lived carbonate platform setting during the early Cambrian. The latter then evolved into a rifted margin with deposition of thick siliciclastic successions in graben structures during the middle to late Cambrian. The detritus in these basins was of local origin, and a contribution from a broader source area (encompassing parts of the West African Craton) can only be demonstrated for postrifting, i.e., laterally extensive sandstone bodies that seal the former graben. In a broader paleotectonic context, it is suggested that this Cambrian rifting is linked to the opening of the Rheic Ocean, and that several peri-Gondwanan terranes (Meguma and Cadomia–Iberia) may have been close to the Meseta Domain before drifting, albeit some of them seem to have been constituted by a distinctly different basement.


Lithosphere ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 767-783 ◽  
Author(s):  
Christopher Clinkscales ◽  
Paul Kapp

Abstract The Middle–Late Jurassic to earliest Cretaceous fold belts of the Yanshanian orogen in North China remain enigmatic with respect to their coeval deformation histories and possible relationship to the contemporaneous Cordilleran-style margin of eastern Asia. We present geological mapping, structural data, and a >400-km-long, strike-perpendicular balanced cross section for the Taihang-Luliangshan fold belt exposed in the late Cenozoic central Shanxi Rift. The northeast-southwest–trending Taihang-Luliangshan fold belt consists of long-wavelength folds (∼35–110 km) with ∼1–9 km of structural relief cored by Archean and Paleoproterozoic metamorphic and igneous basement rocks. The fold belt accommodated ≥11 km of northwest-southeast shortening between the Taihangshan fault, bounding the North China Plain, in the east and the Ordos Basin in the west. Geological mapping in the Xizhoushan, a northeast-southwest–oriented range within the larger Taihangshan mountain belt, reveals two major basement-cored folds: (1) the Xizhou syncline, with an axial trace that extends for ∼100 km and is characterized by a steep to overturned forelimb consistent with a southeast sense of vergence, and (2) the Hutuo River anticline, which exposes Archean–Paleoproterozoic rocks in its core that are unconformably overlain by shallowly dipping (<∼20°) Lower Paleozoic rocks. In the Luliangshan, Mesozoic structures include the Luliang anticline, the largest recognized anticline in the region, the Ningjing syncline, which preserves a complete section of Paleozoic to Upper Jurassic strata, and the Wuzhai anticline; together, these folds are characterized by a wavelength of ∼45–50 km. Shortening in the Taihang-Luliangshan fold belt is estimated to have occurred between ca. 160 Ma and 135 Ma, based on the age of the youngest deformed Upper Jurassic rocks in the Ningjing syncline, previously published low-temperature thermochronology, and regional correlations to better-studied Yanshanian fold belts. The timing of basement-involved deformation in the Taihang-Luliangshan fold belt, which formed >1000 km from the nearest plate margin, corresponds with the termination of arc magmatism along the eastern margin of Asia, implying a potential linkage to the kinematics of the westward-subducting Izanagi (paleo-Pacific) plate.


1979 ◽  
Vol 93 ◽  
pp. 1-40
Author(s):  
P.R Dawes ◽  
N.J Soper

Structural and stratigraphic detaiIs collected during reconnaissance fjeld work in northern Peary Land in 1969 are presented to substantiate the rather general accounts of the North Greenland fold belt hitherto published. The structural detail, largely in the form of graphic profiles sketched in the fieid, is referred to a structural frarnework in which three main deformation phases are recognised. The fold belt displays a roughly E-W zonation based on the progressive northerly increasing intensity of deformation and metamorphic effects that culminate along the northern coast in amphibolite-facies mineral assemblages in complexly folded schist lithologies. It is stressed that, while the conspicuous structural character of the fold belt is its northerly vergence seen particularly in the northernmost part, the detailed structural make-up of the fold belt is complex. Fold style and vergence vary considerably and the southern margin of the fold belt, autochthonous with respect to the platform, is characterised by south-verging folds. Some stratigraphical data is presented particularly from the Lower Palaeozoic sequence at the southern part of the fold belt that iIIustrates the basinal clastic facies at the sheIf-basin margin.


1981 ◽  
Vol 106 ◽  
pp. 77-84
Author(s):  
N Springer

This report presents the first Rb-Sr age determinations obtained on low-grade metasediments within the eastern part of the North Greenland fold belt. Samples were collected during the 1979 field mapping in eastem Johannes V. Jensen Land, the results ofwhich have been published elsewhere (Soper et al., 1980). Material selected for this study was taken from moderately folded rocks of the Polkorridoren Group and from the northem part of the fold belt where deformation is intense and sedimentary structures are rarely preserved (fig. 23). The principles and methods of isotopic dating of sedimentary rocks applied in this study have been treated in a recent paper by Clauer (1979).


1982 ◽  
Vol 108 ◽  
pp. 5-13
Author(s):  
R.H Wagner ◽  
N.J Soper ◽  
A.K Higgins

Late Permian plant impressions comprising six taxa have been obtained from the North Greenland fold belt. Rhipidopsis, a probable ginkgophyte, occurs together with the fems Prynadaeopteris venusta Radczenko and Pecopteris (Asterotheca?) cf. P. (A?) helenaeana Zalessky, the sphenophyte Sphenophyllum cf. S. biarnicum Zalessky the cordaitean Cordaites cf. C. sylovaensis (Neuburg) Meyen and a possibie conifer branch fragment. The assemblage invites comparison with the Pechora flora of the northem Pre-Urals, and also with that of Mongolia and north-eastern China. These may be warm temperate floras on approximately the same palaeolatitude.


1980 ◽  
Vol 99 ◽  
pp. 89-98
Author(s):  
N.J Soper ◽  
A.K Higgins ◽  
J.D Friderichsen

This report concerns that part of the North Greenland fold belt in north Peary Land (Johannes V. Jensen Land) which lies east of Polkorridoren (the glacier filled depression between Frigg Fjord and Sands Fjord) and north of the Harder Fjord fault (fig. 40). The rocks forming the fold belt are mainly Lower Palaeozoic quartzites, carbonates, arkoses and shales, which are an extension of the Hazen Trough that stretched through the Queen Elizabeth Islands of Canada and across northern Greenland. Because of the northward increase in deformation and metamorphic grade, it is convenient to subdivide the region into a southerly, less deformed, area in which a stratigraphical sequence ean be established, and a northerly area in which only lithological units can be mapped. The dividing line corresponds to that, north of which, 'way-up' criteria cannot be used owing to the masking of the sedimentation structures by a pervasive schistosity. This line runs approximately from the northern end of Paradisfjeld to Bliss Bugt.


1974 ◽  
Vol 65 ◽  
pp. 11-13
Author(s):  
W.B.N Berry ◽  
A.J Boucot ◽  
P.R Dawes ◽  
J.S Peel

The precise age of the youngest part of the geosynclinal fill of the North Greenland fold belt has been the subject of important discussion, particularly with regard to the problem of dating the Palaeozoic diastrophism (Kerr, 1967; Dawes, 1971). Since Lauge Koch's field work between 1916 and 1923 it has been known that strata bearing Monograptus priodon were involved in the folding (Koch, 1920), indicating the presence of Silurian of Llandovery-Wenlock age. In addition, Poulsen (1934) identified Cyrtograptus cf. C. multiramus and Monograptus bohemicus in collections made by Koch from unfolded shales on the platform, to the south of the fold belt, which demonstrated that the section included Wenlock and early Ludlow strata.


1986 ◽  
Vol 128 ◽  
pp. 37-54
Author(s):  
A.K Higgins

A historical review of geological research in North Greenland is followed by a summary of the main results of the 1978-80 GGU expeditions to the region. New outcrops of Archaean and early Proterozoic crystalline rocks are recorded only as xenoliths in dykes and volcanic centres. A revised stratigraphy is applied to the middle Proterozoic Independence Fjord Group sandstones, while petrographic and isotopic studies have been made of the cross-cutting Midsommersø dolerites and the overlying Zig-Zag Dal Basalt Formation. No convincing evidence has been found of a Carolinidian orogenic episode separating these units from succeeding late Proterozoic sedimentary sequences. Lower Palaeozoic sediments dominate North Greenland and are divided into southern shelf and northern trough successions; new or revised stratigraphies are now applied in both settings. The shelf-trough boundary can be shown to have moved south with time, and a major early Silurian expansion of the trough is related to shelf subsidence and a new phase of turbidite deposition derived from the rising East Greenland Caledonian mountains. Devonian - Middle Carboniferous (Ellesmerian) deformation brought deposition to a close and created the North Greenland fold belt, in which deformation intensity and metamorphic grade increase northwards. Thin-skinned thrusting in association with west or south-facing folds is important in southern areas; this is one of the main differences in interpretation compared to earlier work in the fold belt. New outcrops of post-ElIesmerian sediments (Wandel Sea Basin) have mainly been recorded as fault or thrust bounded sequences; a new stratigraphy is applied to the Wandel Sea Basin succession. Cretaceous - Tertiary events include a suite of volcanic centres, dyke swarms, the Kap Washington Group volcanics, and faults and thrusts of Tertiary (Eurekan) age; all have been studied anew, as have the Quaternary deposits.


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