scholarly journals The Late Triassic Molasse Deposits in Central Jilin Province, NE China: Constraints on the Paleo-Asian Ocean Closure

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 223
Author(s):  
Zuozhen Han ◽  
Jingjing Li ◽  
Chenlin Zhu ◽  
Wenjian Zhong ◽  
Zhigang Song
Keyword(s):  
Jilin Province ◽  
Granitic Rocks ◽  
Late Triassic ◽  
Ne China ◽  
High Field Strength ◽  
Zircon Age ◽  
Second Stage ◽  
Magmatic Rocks ◽  
Isotopic Analyses ◽  
Final Closure

This paper presents a new detailed study including zircon U-Pb-Hf isotopic, whole-rock geochemical and Sr-Nd isotopic analyses of conglomerate and granitic pebbles from the molasse deposits in central Jilin Province, NE China. These data are used to better constrain the Late Permian–Triassic tectonic evolution regarding particularly the final closure of the Paleo-Asian Ocean (PAO) along the Changhun-Yanji suture (CYS). Zircon U-Pb data indicate that the granitic pebbles formed in the end-Permian (254–253 Ma). The youngest detrital zircon age of 231 Ma from the conglomerate, and presence of the overlying Upper Triassic Sihetun Formation suggests that the molasse deposits on the Jin′gui Island formed during the Late Triassic. The end-Permian granitic rocks display high SiO2 (66.07–74.77 wt %), with low MgO (0.55–2.05 wt %) and Mg# (31.61–43.64) values, together with depleted Hf and Nd isotopic values (εHf(t) = +1.61 to +11.62; εNd(t) = +3.3 to +4.2; (87Sr/86Sr)i = 0.706458–0.706842) and juvenile second-stage Hf model ages (1148–512 Ma), suggesting that they were probably generated by the partial melting of a Meso-Neoproterozoic juvenile metabasaltic lower crust. They are characterized by enrichments in large ion lithophile elements (LILEs) and depletions in high field strength elements (HFSEs), with affinities to igneous rocks forming in a subduction-related setting. This, combined with regional coeval subduction-related magmatic rocks, indicates that the PAO still existed along the CYS. In addition, the identification of Late Triassic molasse deposits on the Jin′gui Island in this study, coupled with occurrences of many Early Triassic syn-collisional granitoids along the CYS, indicates that the final closure of the PAO took place prior to the Late Triassic.

scholarly journals Geochemistry and Zircon U-Pb-Hf Isotopes of Metamorphic Rocks from the Kaiyuan and Hulan Tectonic Mélanges, NE China: Implications for the Tectonic Evolution of the Paleo-Asian and Mudanjiang Oceans

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 836
Author(s):  
Zuozhen Han ◽  
Jingjing Li ◽  
Zhigang Song ◽  
Guyao Liu ◽  
Wenjian Zhong ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Middle Triassic ◽  
Late Triassic ◽  
Metamorphic Rocks ◽  
Late Permian ◽  
Early Permian ◽  
Ne China ◽  
The North ◽  
Tectonic Mélange ◽  
Final Closure

The Late Paleozoic–Early Mesozoic tectonic evolution of the Changchun-Yanji suture (CYS) was mainly associated with the Paleo-Asian and Mudanjiang tectonic regimes. However, the spatial and temporal overprinting and variations of these two regimes remains are still dispute. In order to evaluate this issue, in this contribution, we present new zircon U-Pb ages and a whole-rock geochemical and zircon Hf isotopic dataset on a suite of metamorphic rocks, including gneisses, actinolite schist, leptynites, and biotite schists, from tectonic mélanges in northern Liaoning and central Jilin provinces, NE China. Based on zircon LA-ICP-MS U-Pb dating results, protoliths show wide ranges of aging spectrum, including Paleoproterozoic (2441 Ma), Early Permian (281 Ma), Late Permian (254 Ma), and Late Triassic (230 Ma). The Permian protoliths of leptynites from the Hulan Tectonic Mélange (HLTM) and gneisses from the Kaiyuan Tectonic Mélange (KYTM) exhibit arc-related geochemical signatures, implying that the Paleo-Asian Ocean (PAO) did not close prior to the Late Permian. The Late Triassic protoliths of gneisses from the KYTM, in combination with previously reported coeval igneous rocks along the CYS, comprises a typical bimodal igneous suite in an E–W-trending belt, suggesting a post-orogenic extensional environment. Consequently, we infer that the final closure of the PAO took place during the Early–Middle Triassic. The Early Permian protoliths of biotite schists from the HLTM are alkali basaltic rocks and contain multiple older inherited zircons, which, in conjunction with the geochemical features of the rocks, indicate that they were generated in a continental rift related to the initial opening of the Mudanjiang Ocean (MO). Data from this contribution and previous studies lead us to conclude that the MO probably opened during the Middle Triassic, due to the north–south trending compression caused by the final closure of the PAO.

scholarly journals Geochronology and geochemistry of Permo-Triassic sandstones in eastern Jilin Province (NE China): Implications for final closure of the Paleo-Asian Ocean

2019 ◽  
Vol 10 (2) ◽  
pp. 683-704 ◽  
Author(s):  
Qingxiang Du ◽  
Zuozhen Han ◽  
Xiaoli Shen ◽  
Chao Han ◽  
Zhigang Song ◽  
...  
Keyword(s):  
Jilin Province ◽  
Ne China ◽  
Final Closure

The timing of final closure along the Changchun–Yanji suture zone: Constraints from detrital zircon U–Pb dating of the Triassic Dajianggang Formation, NE China

Lithos ◽  
2016 ◽  
Vol 261 ◽  
pp. 216-231 ◽  
Author(s):  
Bin Wang ◽  
Jian-Bo Zhou ◽  
Simon A. Wilde ◽  
Xing-Zhou Zhang ◽  
Shou-Mai Ren
Keyword(s):  
Detrital Zircon ◽  
Suture Zone ◽  
Ne China ◽  
Final Closure

Petrology and geochronology of Paleoproterozoic intrusive rocks, Kiggavik uranium camp, Nunavut

2015 ◽  
Vol 52 (7) ◽  
pp. 495-518 ◽  
Author(s):  
J.M.J. Scott ◽  
T.D. Peterson ◽  
W.J. Davis ◽  
C.W. Jefferson ◽  
B.L. Cousens
Keyword(s):  
Granitic Rocks ◽  
Uranium Deposits ◽  
Zircon Age ◽  
Core Samples ◽  
Thelon Basin ◽  
Intrusive Rocks ◽  
Uranium Exploration ◽  
Melt Infiltration ◽  
Granitic Intrusions ◽  
Baker Lake

We investigated the age and petrology of Paleoproterozoic granitic intrusions in the area of the Kiggavik uranium exploration camp, near the southeast margin of the Aberdeen subbasin of the Thelon Basin. A subset of these intrusions (e.g., the Lone Gull stock) is spatially associated with and mineralized by basement hosted, unconformity-related uranium deposits. Surface (outcrop) samples have field relations, textures, and compositions consistent with Hudson Suite granitoids and mixtures of monzogranite with minette. We obtained U–Pb (zircon) ages ranging from ca. 1818 to 1840 Ma, within the known range of the Hudson Suite and cogenetic minettes of the Baker Lake Group (1.80–1.84 Ga). Core samples of granitic rocks adjacent to mineralized zones are more complex and indicate an influence from the younger Nueltin Granite (Kivalliq Igneous Suite, ca. 1.77–1.73 Ga). One sample from the Lone Gull stock contains two zircon populations in texturally distinctive domains, one at 1806 ± 41 Ma and the other at 1748 ± 9.4 Ma. A porphyritic hypabyssal syenite below the Bong deposit yielded a U–Pb zircon age of 1837.8 ± 7.7 Ma and a U–Pb titanite age of 1758.5 ± 44 Ma. We recognize a Kivalliq-age overprint in the form of metasomatism and partial remelting or melt infiltration in the drill core samples, which is not evident at the surface and is consistent with the presence of a Nueltin Granite intrusive complex at depth. The geochemistry and primary igneous textures of the Bong syenite, including its euhedral zircons, resemble those of lava flows near the base of the Baker Lake Group, and we recognize a mixed magma (i.e., Martell Syenite) continuum between intrusive Hudson granitoids and minette with extrusive equivalents in the lower felsic minette member of the Christopher Island Formation.

Re-Os and U-Pb Geochronology of Porphyry and Skarn Types Copper Deposits in Jilin Province, NE China

2015 ◽  
Vol 65 (4) ◽  
pp. 394-404 ◽  
Author(s):  
Yong Zhang ◽  
Shu-Wen Xing ◽  
Quan-Heng Song ◽  
Yan Wang ◽  
Zheng-Tao Yu ◽  
...  
Keyword(s):  
Jilin Province ◽  
Ne China ◽  
Copper Deposits

K–Ar age determinations on the fine fractions of clay mineral ‘Crystallinity Index Standards’ from the Palaeozoic mudrocks of southwest England

Clay Minerals ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Anna C. Schomberg ◽  
Klaus Wemmer ◽  
Laurence N. Warr ◽  
Georg H. Grathoff
Keyword(s):  
Clay Mineral ◽  
Crystallinity Index ◽  
White Mica ◽  
Early Jurassic ◽  
Late Triassic ◽  
X Ray Diffraction ◽  
Middle Ordovician ◽  
Late Cambrian ◽  
Isotopic Analyses ◽  
Mineral Crystallinity

AbstractClay mineral ‘Crystallinity Index Standards’ (CIS) composed of Palaeozoic mudrocks from southwest England were investigated systematically in five sub-fractions per sample for the first time. X-ray diffraction was used to determine mineral assemblages, calibrated 001 illite full-width-at-half-maximum (FWHM) values and illite polytype compositions, in addition to K–Ar isotopic analyses of all fine fractions. The FWHM results of the <2 µm fraction are consistent with previous studies and reflect the range of diagenetic to epizonal grades covered by the sample set SW1 to SW7 (~0.61–0.26°2θ). Diagenetic and lower anchizone samples also show significant broadening of 001 illite reflections in the finer fractions and contain mixtures of authigenic 1M + 1Md illite and detrital 2M1 white mica polytypes suitable for illite age analysis. The estimated end-member ages of the Bude (SW1-1992) and younger Crackington (SW3-2000) mudstones yield detrital ages of Late Cambrian to Middle Ordovician (493–457 Ma) and a broad range of 1M + 1Md illite ages between Middle Permian and Early Jurassic (271–190 Ma). The detrital age of the stratigraphically older Crackington Formation mudrock (SW2-1992) is Late Devonian (384–364 Ma) with 1M + 1Md illite ages between Late Triassic and Early Jurassic (219–176 Ma). The origin of Mesozoic 1M + 1Md illite ages may represent neocrystallized illite associated with Mesozoic hydrothermal events or similar events that thermally reset older authigenic illite with partial loss of radiogenic argon and no renewed crystal growth. In contrast, upper anchizonal and epizonal Devonian slates (SW3-2012, SW4-1992, SW6-1992 and SW7-2012) contain only the 2M1 polytype, with K–Ar ages younger than the stratigraphic age. The three finest fractions of SW4-1992 yield consistent Late Carboniferous ages (331–304 ± 7 Ma) that are considered to date the neocrystallized 2M1 mica. Most fractions of epizonal slate (SW6-1992, SW7-2012) yield Early Permian ages (293.6–273 Ma) corresponding to published cooling ages of the Tintagel High-Strain Zone and the intrusion of the Bodmin granite (291.4 ± 0.8 Ma). These first K–Ar age constraints for the fine fractions of the CIS should provide useful reference values for testing analytical procedures of illite age analysis.

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