Provenance of Middle to Late Triassic sedimentary rocks in the Zoige Depression in the NE part of the Songpan-Ganzi Flysch Basin: Petrography, heavy minerals, and zircon U-Pb geochronology

2017 ◽  
Vol 52 ◽  
pp. 449-462 ◽  
Author(s):  
Yan Tang ◽  
Yunpeng Zhang ◽  
Lili Tong
Keyword(s):  
Sedimentary Rocks ◽  
Heavy Minerals ◽  
Late Triassic

Provenance of Jurassic sedimentary rocks of south-central Quesnellia, British Columbia: implications for paleogeography

2004 ◽  
Vol 41 (1) ◽  
pp. 103-125 ◽  
Author(s):  
Nathan T Petersen ◽  
Paul L Smith ◽  
James K Mortensen ◽  
Robert A Creaser ◽  
Howard W Tipper
Keyword(s):  
Detrital Zircon ◽  
Middle Jurassic ◽  
Sedimentary Rocks ◽  
Source Area ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Nd Isotopes ◽  
South Central ◽  
History Of

Jurassic sedimentary rocks of southern to central Quesnellia record the history of the Quesnellian magmatic arc and reflect increasing continental influence throughout the Jurassic history of the terrane. Standard petrographic point counts, geochemistry, Sm–Nd isotopes and detrital zircon geochronology, were employed to study provenance of rocks obtained from three areas of the terrane. Lower Jurassic sedimentary rocks, classified by inferred proximity to their source areas as proximal or proximal basin are derived from an arc source area. Sandstones of this age are immature. The rocks are geochemically and isotopically primitive. Detrital zircon populations, based on a limited number of analyses, have homogeneous Late Triassic or Early Jurassic ages, reflecting local derivation from Quesnellian arc sources. Middle Jurassic proximal and proximal basin sedimentary rocks show a trend toward more evolved mature sediments and evolved geochemical characteristics. The sandstones show a change to more mature grain components when compared with Lower Jurassic sedimentary rocks. There is a decrease in εNdT values of the sedimentary rocks and Proterozoic detrital zircon grains are present. This change is probably due to a combination of two factors: (1) pre-Middle Jurassic erosion of the Late Triassic – Early Jurassic arc of Quesnellia, making it a less dominant source, and (2) the increase in importance of the eastern parts of Quesnellia and the pericratonic terranes, such as Kootenay Terrane, both with characteristically more evolved isotopic values. Basin shale environments throughout the Jurassic show continental influence that is reflected in the evolved geochemistry and Sm–Nd isotopes of the sedimentary rocks. The data suggest southern Quesnellia received material from the North American continent throughout the Jurassic but that this continental influence was diluted by proximal arc sources in the rocks of proximal derivation. The presence of continent-derived material in the distal sedimentary rocks of this study suggests that southern Quesnellia is comparable to known pericratonic terranes.

The provenance of Middle Jurassic sandstones in the Scotian Basin: petrographic evidence of passive margin tectonics 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Geological Survey of Canada Contribution 20110319.

2012 ◽  
Vol 49 (12) ◽  
pp. 1463-1477 ◽  
Author(s):  
Gang Li ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Mineral Chemistry ◽  
Passive Margin ◽  
Heavy Minerals ◽  
Late Triassic ◽  
Cape Breton Island ◽  
Grand Banks ◽  
Meguma Terrane ◽  
Geomorphological Evolution

The tectonic and geomorphological evolution of the Scotian margin and its hinterland is poorly known between Late Triassic rifting and the Early Cretaceous progradation of major deltas. This study determined sedimentary provenance of Middle Jurassic Mohican Formation sandstones from three wells using heavy minerals and mineral chemistry. Indicator minerals such as xenotime, altered ilmenite, and varietal types of garnet and tourmaline are similar to those in Hauterivian–Barremian sandstones in the western Scotian Basin, which are almost exclusively derived from the Meguma terrane. The wells adjacent to the Canso Ridge have more zircon and less ilmenite, indicating a greater contribution of polycyclic reworking, but with an ultimate source in the Meguma terrane. Zircon and ilmenite were likely derived in part from Carboniferous sandstones in eastern mainland Nova Scotia and Cape Breton Island. Any river drainage from the inboard terranes of the Appalachians either was diverted through the Fundy Basin or entered the easternmost Scotian Basin, where the Mohican Formation is 5.5 km thick, along the linear continuation of the southwest Grand Banks transform. Such sediment did not reach the Canso Ridge, suggesting that the Cobequid–Chedabucto fault zone in Orpheus graben was not a significant physiographic feature. This tectonically controlled paleogeography in the Middle Jurassic is quite different from that during active rifting in the Late Triassic – Early Jurassic. Middle Jurassic quiescence was followed in the Tithonian – Early Cretaceous by renewed tectonic uplift associated with rifting of Grand Banks from Iberia and Labrador from Greenland.

Revised stratigraphy of the Takla Group, north-central British Columbia

1977 ◽  
Vol 14 (2) ◽  
pp. 318-326 ◽  
Author(s):  
J. W. H. Monger ◽  
B. N. Church
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Lower Jurassic ◽  
Upper Triassic ◽  
Late Triassic ◽  
North Central ◽  
Volcaniclastic Rocks ◽  
Jurassic Rocks

The Takla Group of north-central British Columbia as originally defined contained volcanic and sedimentary rocks of Late Triassic and Jurassic ages. As redefined herein, it consists of three formations in the McConnell Creek map-area. Lowest is the Dewar Formation, composed of argillite and volcanic sandstone that is largely the distal equivalent of basic flows and coarse volcaniclastic rocks of the Savage Mountain Formation. These formations are overlain by the volcaniclastic, basic to intermediate Moosevale Formation. These rocks are Upper Triassic (upper Karnian and lower Norian). They are unconformably overlain by Lower Jurassic rocks of the Hazelton Group.

Upper Paleozoic to lower Mesozoic strata and their conodonts, western Coast Plutonic Complex, British Columbia

1985 ◽  
Vol 22 (9) ◽  
pp. 1329-1344 ◽  
Author(s):  
G. J. Woodsworth ◽  
M. J. Orchard
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Late Triassic ◽  
Western Coast ◽  
Upper Paleozoic ◽  
Facies Metamorphism ◽  
Volcanic Suite ◽  
Plutonic Complex ◽  
Coast Plutonic Complex ◽  
Greenschist Facies Metamorphism

Six lithologic units, including two newly named formations, were mapped on Randall, Dunira, and nearby islands. The islands are characterized by greenschist-facies metamorphism and westerly directed thrusting. The oldest unit is a Late Mississippian, massive limestone on Ducie Island. The Dunira Formation, composed of thin-bedded limestone and siltstone, is Early and Middle Pennsylvanian in age. It is unconformably overlain by limestone and dolomite of the Upper Triassic Randall Formation. The Randall Formation grades upwards into a green phyllitic unit of Late Triassic(?) age. Rhyolitic and more mafic volcanic rocks may represent a bimodal volcanic suite of Early Jurassic age, based on a U–Pb date of 188 Ma on zircons. These five units correlate with rocks in the Alexander Terrane in southeastern Alaska. The sixth and presumed youngest unit consists of flysch-like sedimentary rocks of probable Middle Jurassic to Early Cretaceous age that may correlate with rocks of the Gravina–Nutzotin belt. The three older units yielded 15 conodont genera from 29 localities. The 13 Paleozoic genera are described and illustrated.

Paleozoic volcanic assemblages and volcanogenic massive sulfide deposits near Tulsequah, British Columbia

1984 ◽  
Vol 21 (3) ◽  
pp. 379-381
Author(s):  
Joanne Nelson ◽  
John G. Payne
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Massive Sulfide ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Volcanogenic Massive Sulfide ◽  
Small Bodies ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Volcanogenic Massive Sulfide Deposits

New fossil, structural, and lithological evidence shows that the dominantly andesitic terrane near the junction of the Taku and Tulsequah rivers, northwestern British Columbia, is a proximal facies, roughly age equivalent to late Paleozoic tuffaceous and argillaceous sedimentary rocks exposed near Tatsamenie Lake, rather than of Late Triassic age as previously mapped. Fusulinids from the Tulsequah sequence are Middle Pennsylvanian, whereas the limestones at the top of the Paleozoic section near Tatsamenie Lake are of Permian age. The Tulsequah sequence hosts the Tulsequah Chief, Big Bull, and Ericksen – Ashby massive sulfide deposits, which arc associated with small bodies of rhyolite.

scholarly journals Middle–Late Triassic sedimentary provenance of the southern Junggar Basin and its link with the post-orogenic tectonic evolution of Central Asia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jialin Wang ◽  
Chaodong Wu ◽  
Yue Jiao ◽  
Bo Yuan
Keyword(s):  
Central Asia ◽  
Detrital Zircon ◽  
Tectonic Evolution ◽  
Sedimentary Rocks ◽  
Junggar Basin ◽  
Upper Triassic ◽  
Late Triassic ◽  
The North ◽  
Sedimentary Provenance ◽  
Source To Sink

AbstractDue to the unknown Triassic volcanism in the Junggar Basin, the Middle–Late Triassic sedimentary provenance in the southern Junggar Basin (SJB) has long been controversial. Detrital zircon grains from 13 samples of the Middle–Upper Triassic Xiaoquangou Group in the SJB were analyzed using zircon U–Pb geochronology to constrain the provenance of Triassic sedimentary rocks and to further understand their source-to-sink system. Comparison of detrital zircon U–Pb age distributions for 13 samples reveals that the Triassic age populations predominate in sediments of the northern Bogda Mountains, with subordinate in the southern Bogda Mountains, and no or minimal in the North Tianshan (NTS). Coupled with sandstone petrological, sedimentary geochemical and paleocurrent data, the Triassic detrital zircon grains of the Xiaoquangou Group in the SJB were probably input from the Bogda Mountains. As Pennsylvanian and Mississippian zircon grains are mainly derived from the NTS and Central Tianshan (CTS), the provenance of the Xiaoquangou Group includes the NTS, CTS and Bogda Mountains. But the different samples in different sink areas have different provenances, originating from at least four source-to-sink systems. The supply of sediments from the Bogda Mountains started in the Late Triassic, suggesting initial uplift of the Bogda Mountains.

Reappraisal of the Mesozoic tectonic transition from the Paleo-Tethyan to Paleo-Pacific domains in South China

2021 ◽  
Author(s):  
Chengshi Gan ◽  
Yuzhi Zhang ◽  
Yuejun Wang ◽  
Xin Qian ◽  
Yang Wang
Keyword(s):  
South China ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Sedimentary Rocks ◽  
Early Jurassic ◽  
Igneous Rocks ◽  
Late Triassic ◽  
Geochemical Data ◽  
South China Block ◽  
Tectonic Transition

The southeastern (SE) South China Block was mainly influenced by the Paleo-Tethyan and Paleo-Pacific dynamic domains during the Mesozoic. The initial timing of the tectonic transition between these two domains in the SE South China Block still remains debated. The transition would affect the nature of the lithosphere and material provenance of sediments, and, therefore, igneous and sedimentary rocks in the area could record such dynamic processes. In this study, published geochronological and geochemical data of the Triassic and Jurassic igneous rocks and detrital zircon data of contemporaneous sedimentary rocks in the SE South China Block were compiled, aiming to provide constraints on the tectonic transition via tracing the spatial-temporal variations in the nature of the lithosphere and sedimentary provenance signals. The compiled results suggest that the magmatic intensity and volume decreased significantly from the Late Triassic to Early−Middle Jurassic, with an obvious magmatic quiescence between them, and increased from the Early−Middle Jurassic to Late Jurassic. The εNd(t) and zircon εHf(t) values of mafic rocks, granitoids, and shoshonitic rocks remarkably increased from the Late Triassic to Early−Middle Jurassic, indicative of variations in the lithospheric mantle and continental crust. Such variations suggest that the initial tectonic transition occurred at the earliest Early Jurassic. Based on the southward paleocurrents from Early Jurassic sandstone, E-W−trending extension of Early−Middle Jurassic mafic and shoshonitic rocks, and similar sedimentary provenances of Late Triassic and Early−Middle Jurassic sedimentary rocks, these features imply that the SE South China Block was not immediately influenced by the Paleo-Pacific domain during the Early−Middle Jurassic. However, from the Early−Middle Jurassic to Late Jurassic and Early Cretaceous, the spatial distribution, geochemical signatures, magmatic intensity, and magmatic volume of igneous rocks and provenance of sedimentary rocks exhibit obvious variations, and the regional fold hinge direction changed from E-W−trending to NE-trending, suggesting significant effects from Paleo-Pacific subduction on the SE South China Block. Thus, the Mesozoic tectonic transition from the Paleo-Tethyan to the Paleo-Pacific dynamic domain in the SE South China Block likely occurred during the Early−Middle Jurassic.

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