Genesis and implications of the Late Jurassic Hailesitai granites in the northern Greater Khingan Range: evidence from zircon U–Pb dating and Hf isotope

2016 ◽  
Vol 154 (5) ◽  
pp. 963-982 ◽  
Author(s):  
PINGPING ZHU ◽  
QIUMING CHENG ◽  
ZHENJIE ZHANG ◽  
ZIYE WANG
Keyword(s):  
Inductively Coupled Plasma ◽  
Late Jurassic ◽  
Tectonic Setting ◽  
Hf Isotope ◽  
Source Rocks ◽  
High Potassium ◽  
Inductively Coupled ◽  
Depleted Mantle ◽  
Two Stages ◽  
Extensional Collapse

AbstractThe tectonic setting and geodynamic model of the Greater Khingan Range (GKR) is highly controversial due to the lack of reliable geological, isotopic and geochronological evidence. In the current study, the Hailesitai pluton, located at the west of the suture between the northern and southern GKR in the east of the Central Asian Orogenic Belt, is selected to address this issue. These granites of the high potassium calc-alkaline series belong to the A1-type granites with typical geochemical characteristics including high contents of Al2O3, extremely low contents of Ti, P, enriched LREE, LILE, depleted HFSE, and a medium Eu negative anomaly. Laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) zircon U−Pb dating indicates that the granites can be divided into two stages: c. 152 and c. 161 Ma. The intrusion of A1-type granites at ~161 Ma implies that intra-plate orogenesis of the northern GKR started at c. 161 Ma at latest. The Hailesitai pluton has relatively homogeneous Hf isotope compositions with a εHf (t) value (+6.0 − +9.0), and two-stage depleted mantle model ages of 579−738 Ma show that the original magma is a mixture of juvenile and crustal source rocks. Extensional collapse of the Mongol−Okhotsk belt between the Siberia block and the northern GKR resulted in the formation of late Jurassic A1-type granites in the northern GKR. The Hailesitai pluton formed in response to post-orogenic extensional collapse of the Mongol–Okhotsk belt, coupled with back-arc extension related to Palaeo-Pacific plate subduction.

Geochemical Characteristics of the Campano-Maastrictian Sediments of the Anambra Basin, Southeastern Nigeria - Implication For Provenance, Paleodepositional Environment, Maturity and Tectonic Setting

2021 ◽  
Author(s):  
Michael Edirin Okiotor ◽  
EDeh Desiree Ogueh
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Source Rocks ◽  
Sediment Provenance ◽  
Southeastern Nigeria ◽  
Inductively Coupled ◽  
Anambra Basin ◽  
Plasma Mass Spectrometry ◽  
Chemical Index Of Alteration

Abstract The present study investigates the Anambra Basin shales to determine the provenance and maturity of the sediments using standard geochemical techniques. Twelve (12) representative samples recovered from shale sequences of The Mamu Formation and Nkporo Group of The Anambra Basin were studied to determine the sediment provenance, paleoenvironment, diagenetic conditions, maturity as well as the tectonic setting. To consider in detail and establish the inherent constituents of the Major minerals, Trace and Rare Earth elements, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses techniques was employed. The detrital minerals determined are Al2O3 (18.27% and 21.16%), TiO2 (1.73% and 1.63%) and Fe2O3 (2.78% \ and 2.85%), for Nkporo Group and Mamu Formation respectively. The enrichment of SiO2, Al2O3 and TiO2 (1.14, 1.94, 3.67 respectively) supported by Chemical Index of Alteration (CIA) of 93.54 & 39.55 and Rb/Sr ratio of 0.57 & 0.40, indicate that the Anambra Basin sediments are matured. TiO2/AL2O3 binary plots, Th/Co Vs La/Sc crossplots, Th-Sc-Zr triplots and Cr, Ni concentration suggest mixed provenance of felsic to mafic source rocks for these sediments. From the log (K2O/Na2O) Vs SiO2 crossplots, a passive margin tectonic setting was determined for these sediments.

scholarly journals Two stages of Late Carboniferous to Triassic magmatism in the Strandja Zone of Bulgaria and Turkey

2021 ◽  
pp. 1-14
Author(s):  
Anna Sałacińska ◽  
Ianko Gerdjikov ◽  
Ashley Gumsley ◽  
Krzysztof Szopa ◽  
David Chew ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Age Groups ◽  
Late Carboniferous ◽  
The Balkans ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Tethys Ocean ◽  
Two Stages

Abstract Although Variscan terranes have been documented from the Balkans to the Caucasus, the southeastern portion of the Variscan Belt is not well understood. The Strandja Zone along the border between Bulgaria and Turkey encompasses one such terrane linking the Balkanides and the Pontides. However, the evolution of this terrane, and the Late Carboniferous to Triassic granitoids within it, is poorly resolved. Here we present laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) U–Pb zircon ages, coupled with petrography and geochemistry from the Izvorovo Pluton within the Sakar Unit (Strandja Zone). This pluton is composed of variably metamorphosed and deformed granites which yield crystallization ages of c. 251–256 Ma. These ages are older than the previously assumed age of the Izvorovo Pluton based on a postulated genetic relationship between the Izvorovo Pluton and Late Jurassic to Early Cretaceous metamorphism. A better understanding of units across the Strandja Zone can now be achieved, revealing two age groups of plutons within it. An extensive magmatic episode occurred c. 312–295 Ma, and a longer-lived episode between c. 275 and 230 Ma. Intrusions associated with both magmatic events were emplaced into pre-Late Carboniferous basement, and were overprinted by Early Alpine metamorphism and deformation. These two stages of magmatism can likely be attributed to changes in tectonic setting in the Strandja Zone. Such a change in tectonic setting is likely related to the collision between Gondwana-derived terranes and Laurussia, followed by either subduction of the Palaeo-Tethys Ocean beneath Laurussia or rifting in the southern margin of Laurussia, with granitoids forming in different tectonic environments.

Trace Element Geochemistry and Mineral Inclusions Constraints on the Petrogenesis of a Marble–Hosted Ruby Deposit in Yunnan Province, China

2021 ◽  
Author(s):  
Wenqing Huang ◽  
Pei Ni ◽  
Ting Shui ◽  
Junyi Pan ◽  
Mingsen Fan ◽  
...  
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Yunnan Province ◽  
Geographic Origin ◽  
Source Rocks ◽  
Trace Element Geochemistry ◽  
Mineral Inclusion ◽  
Element Geochemistry ◽  
Inductively Coupled ◽  
Mineral Inclusions

Abstract Primary rubies in the Ailao Shan of Yunnan Province, China, are found in three layers of marble. However, the origin and source rocks of placer rubies in the Yuanjiang area remains unclear. Trace element geochemistry and inclusion mineralogy within these materials can provide information on their petrogenesis and original source. Zircon, rutile, mica group minerals, titanite, and apatite group minerals were the main solid inclusions identified within the placer Yuanjiang rubies, along with other mineral inclusions such as pyrite, pyrrhotite, plagioclase group minerals, and scapolite group minerals. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) measurements showed that the placer rubies are characterized by average values of Mg (31 ppmw), Ti (97 ppmw), V (77 ppmw), Cr (3326 ppmw), Fe (71 ppmw), and Ga (66ppmw). A trace-element oxide diagram, Fe values (<350 ppmw), and the mineral inclusion assemblage suggest marble sources for the placer ruby. Therefore, the Yuanjiang rubies (both primary and placer) are metamorphic, and this fits well with the observations that skarn and related minerals are mostly absent in this deposit. Yuanjiang rubies can be readily separated from the high-iron rubies of different geological types by their Fe content (<1000 ppmw). The discriminators Mg, Ga, Cr, V, Fe, and Ti have potential in separating Yuanjiang rubies from some other marble-hosted deposits, such as Snezhnoe. Nevertheless, geographic origin determination remains a challenge when considering the similarities in compositional features between the Yuanjiang rubies and rubies from some other marble-hosted deposits worldwide (e.g., Luc Yen). The presence of kaolinite group minerals and clusters of euhedral, prismatic zircon crystals in ruby suggest a Yuanjiang origin.

scholarly journals Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria

2017 ◽  
Vol 64 (1) ◽  
pp. 35-52 ◽  
Author(s):  
Emmanuel E. Adiotomre ◽  
Innocent O. Ejeh ◽  
Edwin O. Adaikpoh
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Fluvial Sediments ◽  
Geochemical Analysis ◽  
Sediment Samples ◽  
Inductively Coupled ◽  
Southwest Nigeria ◽  
Plasma Mass Spectrometry ◽  
Quartz Grains

Abstract Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E) and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G). Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E) and greywackes (units FL_C, FL_D, FL_F and FL_G). Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E) parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Yb)n ratios <2.0 (1.53- 1.82, average 1.65) suggest post-Archean protoliths.

scholarly journals Geochemical Classification and Geotectonic Setting of Granitic Gneisses from Southeastern Margin of Western Nigeria Basement

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Mohammed Olatoye Adepoju ◽  
Yinusa Ayodele Asiwaju-Bello
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Calc Alkaline ◽  
Granitic Gneiss ◽  
Basement Complex ◽  
Southwestern Nigeria ◽  
Inductively Coupled ◽  
Continental Arc ◽  
Southeastern Margin ◽  
Geochemical Classification

Chemical whole-rock major oxides and some trace element analyses were done on granitic gneiss rocks located on the southeastern margin of western Nigeria Basement Complex, exposed in parts of Dagbala-Atte District, southwestern Nigeria. This was meant to classify the rocks and to understand the tectonic setting in order to evaluate their crustal evolution. The chemical analyses were done using inductively-coupled plasma mass spectrometer. From the results obtained, these rocks classified into calc-alkaline to shoshonite series with metaluminous to peraluminous varieties, they are I-type granitoids of feroan composition. The granitic gneisses formed from metamorphism of granite and granodiorite. Tectonically, most of the rock samples plotted in the field of island arc, continental arc and continental-collisional granitoids, which indicated that the protolith granite and granodiorite are orogenic and are arc related inferring arc tectonic setting.

Late Jurassic to Early Cretaceous magmatism in the Xiong’ershan gold district, central China: implications for gold mineralization and geodynamics

2019 ◽  
Vol 157 (3) ◽  
pp. 435-457
Author(s):  
Zhenshan Pang ◽  
Fuping Gao ◽  
Yangsong Du ◽  
Yilun Du ◽  
Zhaojian Zong ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Inductively Coupled Plasma ◽  
Late Jurassic ◽  
Gold Mineralization ◽  
Central China ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Metamorphic Basement ◽  
Plasma Mass Spectrometry ◽  
Cretaceous Magmatism

AbstractThe Xiong’ershan area is the third largest gold-producing district in China. The Late Jurassic to Early Cretaceous magmatism in the Xiong’ershan area can be divided into two episodes: early (165–150 Ma) and late (138–113 Ma). Laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) zircon U–Pb dating yields ages of 160.7 ± 0.6 Ma and 127.2 ± 1.0 Ma for the Wuzhangshan and Huashan monzogranites in the Xiong’ershan area, respectively, representing the two magmatic episodes. The Wuzhangshan monzogranites exhibit adakite-like geochemical features (e.g. high Sr/Y ratios, low Yb and Y contents). Their Sr–Nd–Hf isotopic compositions are consistent with those of the amphibolites of the Taihua Group, indicating that the Wuzhangshan monzogranites were formed from partial melting of the Taihua Group metamorphic rocks. Compared to the Wuzhangshan rocks, the Huashan monzogranites have higher MgO, Cr, Co and Ni contents, but lower Sr/Y and Fe3+/Fe2+. All the samples from the Huashan monzogranites plot in the area between the Taihua Group amphibolite rocks and the mantle rocks in the (87Sr/86Sr)t vs εNd(t) and age vs εHf(t) diagrams, suggesting that the Huashan monzogranites were probably generated by mixing of mantle-derived magmas and the Taihua Group metamorphic basement melts. The gold mineralization (136–110 Ma) is coeval with the emplacement of the late-episode magmas, implying that crustal–mantle mixed magma might be a better target for gold mineralization compared to the ancient metamorphic basement melt. The data presented in this study further indicate that the transformation of the lithosphere from thickening to thinning in the Xiong’ershan area probably occurred between ~160 Ma and ~127 Ma, and that the gold mineralization in this area was probably related to lithospheric thinning.

A Cretaceous back-arc basin in the Coast Belt of the northern Canadian Cordillera: evidence from geochemical and neodymium isotope characteristics of the Kluane metamorphic assemblage, southwest Yukon

2001 ◽  
Vol 38 (1) ◽  
pp. 91-103 ◽  
Author(s):  
Jochen E Mezger ◽  
Robert A Creaser ◽  
Philippe Erdmer ◽  
Stephen T Johnston
Keyword(s):  
Late Jurassic ◽  
Metamorphic Rock ◽  
Tectonic Setting ◽  
Source Region ◽  
Canadian Cordillera ◽  
Metasedimentary Rocks ◽  
Depleted Mantle ◽  
Metamorphic Assemblage ◽  
Continental Source ◽  
Back Arc

The Coast Belt of the northern Cordillera in Canada is the locus of the boundary between accreted and ancient North American margin rocks. The largest exposure of metasedimentary rocks in the Coast Belt is the Kluane metamorphic assemblage (KMA), a northwest-striking belt 160 km long of graphitic mica–quartz schist and gneiss with minor interfoliated olivine serpentinite. The KMA does not appear to correlate with other sedimentary or metamorphic rock assemblages in the Canadian Cordillera. To determine its tectonic setting and protolith provenance, we analyzed trace element, rare earth elements, and neodymium isotope compositions of the KMA, of the adjacent pericratonic Aishihik metamorphic suite (AMS) of the Yukon–Tanana terrane, and of adjacent slates of the Dezadeash Formation (DF), filling a Late Jurassic – Early Cretaceous flysch basin. The εNd(0) values of analyzed KMA samples range from –1.4 to –5.6 and depleted mantle model ages (TDM) range from 1.16 to 1.45 Ga. KMA samples are intermediate between more evolved AMS samples (average εNd(0) –25, TDM = 2.6 Ga) and more juvenile DF samples (εNd(0) = +1.9, TDM = 0.95 Ga). The intermediate characteristics of the KMA samples cannot be linked to a known source region and are interpreted to reflect homogeneous mixing from predominantly juvenile and minor evolved sedimentary sources. A compatible tectonic setting is a back-arc basin within influence of a continental source. Eastward subduction of the KMA beneath ancient North America collapsed the back-arc basin by latest Cretaceous time.

INFLUENCE OF ORGANIC MATTER ON Re-Os DATING OF SULFIDES: INSIGHTS FROM THE GIANT JINDING SEDIMENT-HOSTED Zn-Pb DEPOSIT, CHINA

2021 ◽  
Author(s):  
Shiqiang Huang ◽  
Yucai Song ◽  
Limin Zhou ◽  
David L. Leach ◽  
Zhaoshan Chang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Inductively Coupled Plasma ◽  
Elemental Mapping ◽  
Bacterial Reduction ◽  
Inductively Coupled ◽  
Hydrocarbon Reservoir ◽  
Low Concentrations ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Two Stages

Abstract This study evaluates the effect of organic matter impurities on pyrite Re-Os dating, using the giant Jinding sediment-hosted Zn-Pb deposit in China as an example. The Jinding deposit is hosted in a Paleocene evaporite dome that was a hydrocarbon reservoir before mineralization. Pyrite in Jinding formed in two stages: pre-ore (py1) and syn-ore (py2). Two types of py1 are recognized, organic matter-free and organic matter-bearing. The organic matter-free py1 contains homogeneously distributed low concentrations of Re (&lt;2.5 ppb) that yields an isochron age of 51 ± 1 Ma (mean square of weighted deviates [MSWD] = 3.2). This date is interpreted to be the age of py1 formation. The organic matter-bearing py1 contains organic matter inclusions trapped during py1 growth and synchronous with bacterial reduction of sulfate. Elemental mapping with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) shows that the organic matter inclusions have Re signals 1 to 4 orders of magnitude higher than those of pyrite, revealing that organic matter is the major host for Re. Such pyrite separates contain 37 to 1,145 ppb Re. The Re-Os data of organic matter-bearing py1 yield an isochron age of 72.9 ± 0.5 Ma (MSWD = 0.2). This age is older than the actual py1 formation age of 51 ± 1 Ma but overlaps with previously dated bitumen Re-Os isochron age of 68 ± 5 Ma at Jinding, indicating that organic matter inclusions can significantly influence the Re-Os dates of pyrite and likely other sulfides. This study demonstrates that in order to date sulfides formed in organic-rich environments using the Re-Os method, it is necessary to determine the distribution of Re in samples using detailed petrography and LA-ICP-MS trace element mapping plus spot analysis.

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