Late Paleozoic tectonism of the Bogda region in  Chinese North Tianshan: Insights from sedimentary provenance analysis

Author(s):  
Qian Wang ◽  
Guochun Zhao ◽  
Yigui Han ◽  
Jinlong Yao

<p>The Chinese North Tianshan (CNTS) extends E-W along the southern part of the Central Asian Orogenic Belt and has undergone complicated accretion-collision processes in the Paleozoic. This study attempts to clarify the late Paleozoic tectonism in the region by investigating the provenance of the Late Paleozoic sedimentary successions from the Bogda Mountain in the eastern CNTS by U-Pb dating and Lu-Hf isotopic analyses of detrital zircons. Detrital zircon U-Pb ages (N=519) from seven samples range from 261 ± 4 Ma to 2827 ± 32 Ma, with the most prominent age peak at 313 Ma. There are Precambrian detrital zircon ages (~7%) ranged from 694 to 1024 Ma. The youngest age components in each sample yielded weighted mean ages ranging from 272 ± 9 Ma to 288 ± 5 Ma, representing the maximum depositional ages. These and literature data indicate that some previously-assumed “Carboniferous” strata in the Bogda area were deposited in the Early Permian, including the Qijiaojing, Julideneng, Shaleisaierke, Yangbulake, Shamaershayi, Liushugou, Qijiagou, and Aoertu formations. The low maturity of the sandstones, zircon morphology and provenance analyses indicate a proximal sedimentation probably sourced from the East ­Junggar Arc and the Harlik-Dananhu Arc in the CNTS. The minor Precambrian detrital zircons are interpreted as recycled materials from the older strata in the Harlik-Dananhu Arc. Zircon ɛ<sub>Hf</sub>(t) values have increased since ~408 Ma, probably reflecting a tectonic transition from regional compression to extension. This event might correspond to the opening of the Bogda intra-arc/back arc rift basin, possibly resulting from a slab rollback during the northward subduction of the North Tianshan Ocean. A decrease of zircon ɛ<sub>Hf</sub>(t) values at ~300 Ma was likely caused by the cessation of oceanic subduction and subsequent collision, which implies that the North Tianshan Ocean closed at the end of the Late Carboniferous. This research was financially supported by the Youth Program of Shaanxi Natural Science Foundation (2020JQ-589), the NSFC Projects (41730213, 42072264, 41902229, 41972237) and Hong Kong RGC GRF (17307918).</p>

2013 ◽  
Vol 50 (10) ◽  
pp. 1007-1018 ◽  
Author(s):  
Luke P. Beranek ◽  
Victoria Pease ◽  
Robert A. Scott ◽  
Tonny B. Thomsen

Enigmatic successions of deep-water strata referred to as the Nesmith beds and Grant Land Formation comprise the exposed base of the Franklinian passive margin sequence in northern Ellesmere Island, Nunavut. To test stratigraphic correlations with Ediacaran to Cambrian shallow-water strata of the Franklinian platform that are inferred by regional basin models, >500 detrital zircons from the Nesmith beds and Grant Land Formation were analyzed for sediment provenance analysis using laser ablation (LA–ICP–MS) and ion-microprobe (SIMS) methods. Samples of the Nesmith beds and Grant Land Formation are characterized by 1000–1300, 1600–2000, and 2500–2800 Ma detrital zircon age distributions and indicate provenance from rock assemblages of the Laurentian craton. In combination with regional stratigraphic constraints, these data support an Ediacaran to Cambrian paleodrainage model that features the Nesmith beds and Grant Land Formation as the offshore marine parts of a north- to northeast-directed depositional network. Proposed stratigraphic correlations between the Nesmith beds and Ediacaran platformal units of northern Greenland are consistent with the new detrital zircon results. Cambrian stratigraphic correlations within northern Ellesmere Island are permissive, but require further investigation because the Grant Land Formation provenance signatures agree with a third-order sedimentary system that has been homogenized by longshore current or gravity-flow processes, whereas coeval shallow-water strata yield a restricted range of detrital zircon ages and imply sources from local drainage areas or underlying rock units. The detrital zircon signatures of the Franklinian passive margin resemble those for the Cordilleran and Appalachian passive margins of Laurentia, which demonstrates the widespread recycling of North American rock assemblages after late Neoproterozoic continental rifting and breakup of supercontinent Rodinia.


2020 ◽  
Author(s):  
Andrey K. Khudoley ◽  
Dmitriy V. Alexeiev ◽  
S. Andrew DuFrane

<p>Proterozoic microcontinents are widespread in the western part of the Central Asian Orogenic Belt, but their origin remains poorly constrained. The U-Pb dating of detrital zircons in Proterozoic rocks of the southern Kazakhstan and Kyrgyz North Tianshan elucidate depositional ages and evolution of the Precambrian basins and characterize possible links of Precambrian microcontinents in these regions with Gondwana and other cratons.</p><p>Distributions of U-Pb detrital zircon ages in 13 samples from ca 5 km thick flysch-like succession of the Talas and Malyi Karatau ranges (Ishim-Middle-Tianshan microcontinent) show significant similarity. They are characterized by a widespread occurrence of Neoproterozoic grains with peaks at ca 820-800 and 910–860 Ma, almost complete absence of Mesoproterozoic grains and distinct peaks at ca 2040–1990 and 2500–2465 Ma for Paleoproterozoic grains. Archean grains occur in small amount. Close similarity is supported by K-S test indicating that samples have the same or similar provenance, also implying rapid accumulation and similar depositional ages. Main peaks resemble those in the Tarim Craton, suggesting Tarim as likely provenance and pointing to the Gondwana affinity of the Ishim-Middle-Tianshan microcontinent.</p><p>In contrast, detrital zircon populations in 3 samples from the Neoproterozoic quartzites of the North Tianshan microcontinent are dominated by Mesoproterozoic grains ranging in age from ca 1500 to 1000 Ma and contain few Paleoproterozoic grains ca 1800-1650 Ma. Distributions of U-Pb zircon ages in all 3 samples are very similar and resemble those in the early Neoproterozoic quartzites from the Kokchetav area of northern Kazakhstan, recently reported by Kovach et al. (2017). Age peaks in these samples are very different from the ages of magmatic pulses in Gondwana and point that the North Tianshan microcontinent did not have connection with Gondwana.</p><p>The Ishim-Middle-Tianshan microcontinent was rifted out from the Gondwana in late Neoproterozoic and travelled to the north. Origin and travel paths of the North Tianshan microcontinent remain poorly constrained. Widespread occurrence of Mesoproterozoic zircons implies possible links with Baltica, North America or east Siberia, but more detailed study is required to define exact provenance. These two microcontinents welded together in the middle to late Ordovician during amalgamation of the Kazakhstan paleocontinent and were jointly incorporated in Eurasia during the late Paleozoic collisions of the Kazakhstan continent with Siberia, Baltica and Tarim.</p><p>The study was supported by RFBR grant 20-05-00252</p>


Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 371
Author(s):  
Xiaofeng Xie ◽  
Zhenning Yang ◽  
Huan Zhang ◽  
Ali Polat ◽  
Yang Xu ◽  
...  

The middle Mesoproterozoic is a crucial time period for understanding the Precambrian tectonic evolutionary history of the northern Yangtze Block and its relationship with the supercontinent Columbia. The Dagushi Group (Gp) is one of the Mesoproterozoic strata rarely found at the northern margin of the Yangtze Block. U–Pb geochronology and Lu–Hf isotopic analyses of detrital zircons were analyzed for three metamorphic quartz sandstone samples collected from the Luohanling and Dangpuling formations of the Dagushi Gp. These metasandstones yielded major zircon populations at ~2.65 Ga and ~1.60 Ga, respectively. The ~1.60 Ga ages first discovered yield a narrow range of ɛHf(t) values from −1.8 to +1.8, which lie above the old crust evolutionary line of the Yangtze Block, suggesting the addition of mantle material. Trace element data indicate that ~1.60 Ga detrital zircons share a basic provenance, whereby they have low Hf/Th and high Nb/Yb ratios. Zircon discrimination diagrams suggest that the ~1.60 Ga detrital zircon source rocks formed in an intra-plate rifting environment. Dagushi Gp provenance studies indicate that the ~1.60 Ga detrital zircon was most likely sourced from the interior Yangtze Block. Thus, we suggest that the late Paleoproterozoic to early Mesoproterozoic continental break-up occurred at the northern margin of the Yangtze Block.


Geosphere ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1102-1127 ◽  
Author(s):  
William A. Thomas ◽  
George E. Gehrels ◽  
Timothy F. Lawton ◽  
Joseph I. Satterfield ◽  
Mariah C. Romero ◽  
...  

AbstractNew analyses of U-Pb ages along with previously published analyses of detrital zircons from sandstones in the foreland of the Marathon orogen in west Texas have significant implications regarding provenance. The most prominent concentrations of U-Pb ages are at 1200–1000, 700–500, and 500–290 Ma. The accreted Coahuila terrane in the Marathon hinterland and nearby terranes with Gondwanan (Amazonia) affinity include Paleozoic volcanic and plutonic rocks, as well as Precambrian basement rocks. Late Paleozoic Las Delicias arc rocks have ages of 331–270 Ma. Detrital zircons from Upper Jurassic and Lower Cretaceous sandstones, which were deposited in local basins around the Coahuila terrane, provide a record of detritus available from proximal sources within Coahuila, including important peaks at 1040, 562, 422, 414, 373, and 282 Ma. Components of the detrital-zircon populations in the Marathon foreland have unique matches with primary and/or detrital sources in the Coahuila terrane. Although some components of the Marathon populations also have age matches in Laurentia (Appalachians), others do not; however, all components of the Marathon populations have potential sources in Coahuila. Analyses of εHft show generally more negative values in Amazonia than in Laurentia, and εHft values for Marathon sandstones have distributions similar to those in Amazonia. Therefore, the Coahuila terrane provides a provenance for all of the detrital-zircon ages in the Marathon foreland, requiring no mixing from other sources.


2017 ◽  
Vol 156 (3) ◽  
pp. 547-571 ◽  
Author(s):  
GUANZHONG SHI ◽  
GUANGZENG SONG ◽  
HUA WANG ◽  
CHUANYAN HUANG ◽  
BEN LI

AbstractThe Solonker and Shalazhashan belts are hotly debated tectonic units of the Central Asian Orogenic Belt (CAOB), because they may either represent a Permian or Triassic suture zone of the CAOB, or a rifting zone overprinted on an Early Palaeozoic orogen. Provenance analysis of the Upper Palaeozoic sandstones in these belts may provide useful constraints on this issue. This study collected six sandstone samples from three study areas: the Mandula area of the Solonker Belt, the Quagan Qulu area of the Shalazhashan Belt but close to the Alxa block, and the Enger Us area of the Shalazhashan Belt, for framework petrography, zircon morphology, U–Pb and Lu–Hf isotopic analyses. Framework petrography reveals that the Mandula and Enger Us area samples contain high proportions of volcanic fragments, whereas the samples from the Quagan Qulu area include not only volcanic fragments but also significant amounts of biotite and muscovite. The detrital zircons of the Mandula area and the Enger Us area yield two main age groups: (i) 260–330 Ma, with dominant εHf(t) values of –5 to +12; and (ii) 420–550 Ma, with dominant εHf(t) values of –9 to +9, suggesting that Early Palaeozoic arc-related magmatic rocks and Late Palaeozoic syn-depositional volcanic rocks are the main source rocks. The detrital zircons of the Quagan Qulu area have one main age group of 420–500 Ma and some grains of 0.9–1.1 Ga, 1.4–1.5 Ga, 1.8–1.9 Ga and ~ 2.5 Ga, which derive from the northern margin of the Alxa block. The lithological and fossil assemblages of the Upper Palaeozoic sandstones suggest shallow-marine to deep-water depositional environments and a northward-deepening transition. Based on the zircon spectra, sedimentary environment analysis and previous studies, we argue that the Solonker Belt and the Shalazhashan Belt of the CAOB are in extensional basins of a fore-arc or rifting setting.


2007 ◽  
Vol 44 (3) ◽  
pp. 297-316 ◽  
Author(s):  
JoAnne Nelson ◽  
George Gehrels

Two samples of late Paleozoic grit and Late Mississippian quartzite–chert conglomerate collected from southeastern Yukon–Tanana terrane (YTT) — a composite thrust sheet resting structurally above North American parautochthonous strata and intervening imbricate sheets of the late Paleozoic oceanic Slide Mountain terrane — yielded, respectively, 89 and 74 concordant or nearly concordant (<20% discordant) U–Pb ages on single detrital zircons. They provide constraints on the provenance of this allochthonous pericratonic terrane. Zircons in the grit range from 1770 to 2854 Ma, with a well-defined Early Proterozoic peak between 1800 and 2100 Ma. Precambrian zircons in the conglomerate also show a dominant peak between 1800 and 2100 Ma and smaller peaks between 2200 and 3200 Ma, with a few older grains, and younger grains with ages of 998, 1219, 1255, 1256, and 1417 Ma. The conglomerate also yielded three Devonian grains, with ages of 366 ± 23, 373 ± 12, and 379 ± 23 Ma. Their ages are approximately coeval with the oldest felsic to intermediate arc- and rift-related magmatism in the YTT. The age spectra from southeastern YTT units compare closely with those from Mississippian and older pericratonic units in the Coast Mountains, confirming correlations previously made on lithologic grounds. They also strongly resemble detrital zircon populations from craton-derived Paleozoic units of the northern North American autochthon. This robust U–Pb data set lends support to the idea that YTT once formed part of the outer, active margin of the North American continent, prior to Mississippian rifting and marginal ocean basin development.


2020 ◽  
pp. pygs2020-010
Author(s):  
A.C. Morton ◽  
J.I. Chisholm ◽  
D. Frei

New U-Pb isotopic analyses of detrital zircon grains from Namurian and Westphalian sandstones in the central and south parts of the Pennine Basin are combined with published analyses from the same region, to assess existing views on the nature and location of the source areas that supplied the clastic sediment. The study confirms that most sandstones were derived from distant areas to the north, west and south, and that a local source, in the Wales-Brabant High, also supplied sediment at times. The northern sources are thought to lie mainly in Laurentia (East Greenland), with some input from Baltica (Norway). Most sandstones entering from the west are thought to have been supplied from areas of Avalonian basement, with some components recycled from sediments that were themselves derived from the Caledonian belt that lay to the north. An exception is the Clifton Rock: its source is thought to lie entirely in the Irish Caledonides or in southern Scotland. Sandstones supplied from the south contain significant numbers of late Devonian and Carboniferous grains, indicating the inclusion of material eroded from the active Variscan orogenic belt in Europe. Northern provenance prevailed during Namurian and early Langsettian times, then alternated with western supply until the late Langsettian. Western input then dominated through most of Duckmantian times, until superseded in the late Duckmantian by supply from the Variscan orogen. The Woolley Edge Rock, now shown to be an isolated member of the northern group, entered the area just before the earliest sandstone of Variscan origin.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5174702


2018 ◽  
Vol 156 (07) ◽  
pp. 1247-1264 ◽  
Author(s):  
YU LIU ◽  
KUNGUANG YANG ◽  
ALI POLAT ◽  
XIAO MA

AbstractDetrital zircons are often used to constrain the maximum sedimentary age of strata and sedimentary provenance. This study aimed at reconstructing the Cryogenian palaeogeography of the Yangtze Domain based on U–Pb ages and Lu–Hf isotopic signatures of detrital zircons from sandstones in the southeastern part of the Yangtze Domain. U–Pb ages of the youngest detrital zircon grains from the Niuguping, Gucheng and Datangpo formations yielded average ages of 712±24 Ma, 679.2±6.2 Ma and 665.1±7.4 Ma, respectively, which are close to the depositional ages of their respective formations. An integrated study of detrital zircon Lu–Hf isotopes and U–Pb ages from three samples revealed six main peak ages in the samples from the Anhua section atc. 680 Ma,c. 780 Ma,c. 820 Ma,c. 940 Ma,c. 2000 Ma andc. 2500 Ma. The characteristics of the U–Pb ages and Hf isotopes indicate a link between the north and southeast margins of the Yangtze Domain as early asc. 680 Ma, and the provenance of the coeval sedimentary sequences in the SE Yangtze Domain was the South Qinling Block on the northern margin of the Yangtze Domain. The provenance analysis on thec. 680 Ma detritus composing upper Neoproterozoic strata in the Yangtze Domain revealed that the detritus was transported southward from South Qinling to the southeast margin of the Yangtze Domain through the Exi Strait, but was hindered by the Jiangnan Orogenic Belt.


2019 ◽  
Vol 56 (3) ◽  
pp. 247-266
Author(s):  
Ian Anderson ◽  
David H. Malone ◽  
John Craddock

The lower Eocene Wasatch Formation is more than 1500 m thick in the Powder River Basin of Wyoming. The Wasatch is a Laramide synorgenic deposit that consists of paludal and lacustrine mudstone, fluvial sandstone, and coal. U-Pb geochronologic data on detrital zircons were gathered for a sandstone unit in the middle part of the succession. The Wasatch was collected along Interstate 90 just west of the Powder River, which is about 50 km east of the Bighorn Mountain front. The sandstone is lenticular in geometry and consists of arkosic arenite and wacke. The detrital zircon age spectrum ranged (n=99) from 1433-2957 Ma in age, and consisted of more than 95% Archean age grains, with an age peak of about 2900 Ma. Three populations of Archean ages are evident: 2886.6±10 Ma (24%), 2906.6±8.4 Ma (56%) and 2934.1±6.6 Ma (20%; all results 2 sigma). These ages are consistent with the age of Archean rocks exposed in the northern part of the range. The sparse Proterozoic grains were likely derived from the recycling of Cambrian and Carboniferous strata. These sands were transported to the Powder River Basin through the alluvial fans adjacent to the Piney Creek thrust. Drainage continued to the north through the basin and eventually into the Ancestral Missouri River and Gulf of Mexico. The provenance of the Wasatch is distinct from coeval Tatman and Willwood strata in the Bighorn and Absaroka basins, which were derived from distal source (>500 km) areas in the Sevier Highlands of Idaho and the Laramide Beartooth and Tobacco Root uplifts. Why the Bighorn Mountains shed abundant Eocene strata only to the east and not to the west remains enigmatic, and merits further study.


1998 ◽  
Vol 35 (12) ◽  
pp. 1380-1401 ◽  
Author(s):  
George E Gehrels ◽  
Gerald M Ross

U-Pb ages have been determined on 250 detrital zircon grains from Neoproterozoic through Permian miogeoclinal strata in British Columbia and Alberta. Most of the grains in these strata are >1.75 Ga and are interpreted to have been derived from nearby basement provinces (although most grains were probably cycled though one or more sedimentary units prior to final deposition). Important exceptions are Ordovician sandstones that contain grains derived from the Peace River arch, and upper Paleozoic strata with detrital zircons derived from the Franklinian orogen, Salmon River arch (northwestern U.S.A.), and (or) Grenville orogen. These provenance changes resulted in average detrital zircon ages that become progressively younger with time, and may also be reflected by previously reported shifts in the Nd isotopic signature of miogeoclinal strata. In addition to the grains that have identifiable sources, grains of ~1030, ~1053, 1750-1774, and 2344-2464 Ma are common in our samples, but igneous rocks of these ages have not been recognized in the western Canadian Shield. We speculate that unrecognized plutons of these ages may be present beneath strata of the western Canada sedimentary basin. Collectively, our data provide a record of the ages of detrital zircons that accumulated along the Canadian Cordilleran margin during much of Paleozoic time. Comparisons between this reference and the ages of detrital zircons in strata of potentially displaced outboard terranes may help reconstruct the paleogeography and accretionary history of the Cordilleran orogen.


Sign in / Sign up

Export Citation Format

Share Document