The Provenance and Tectonic Settings of the Greywacke Member of the Late Neoproterozoic Hazara Formation Lesser Himalayas, Northern Pakistan: Evidence from Geochemistry and Petrography

The petrographic and geochemical analysis of the greywacke horizon of the late Neoproterozoic Hazara Formation from the Hazara Mountains has been investigated to determine the provenance, tectonic settings and weathering history of the sediments. The Late Neoproterozoic Hazara Formation is a thick sedimentary sequence comprising of greywacke, shale, argillites, siltstone, and limestone. The greywackes are characterized by fine to medium-grained, moderately sorted and sub-angular to sub-rounded framework grains. They are rich in quartz, lithic fragments and clay minerals. The petrographic investigation of the greywackes categorized them as feldspathic greywacke in the QFR diagram. The quartz content is higher in sandstone and may reach to 70%, which indicates a weathered felsic source. Chemical Index of Alteration values of greywacke suggests that the source region has experienced highly weathering conditions with a warm and moist climate. Various geochemical interpretations, elemental ratios like Th/Sc, La/Sc,Th/Cr, and positive Eu anomalies indicate that the greywackes of the Hazara formation derived from a felsic source and were deposited within an active continental margin tectonic settings. The main source area of the sediments of the greywackes was located to south to southeast, which may possibly be the Aravali orogeny, central Indian craton and Bundelkhand craton. Finally, the geochemical data of the major elements point to a felsic igneous provenance for the greywacke.

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Geochemistry of the Paleocene Clastic Rocks From the Southwestern Jianghan Basin, Central China Reveal Their Provenance, Tectonic Setting, and Palaeoenvironment

10.21203/rs.3.rs-956386/v1 ◽

2021 ◽

Author(s):

Kai Yan ◽

Chun-lian Wang ◽

Jiu-yi Wang ◽

Xiao-can Yu ◽

Xiao-hua Teng ◽

...

Keyword(s):

Tectonic Setting ◽

Active Continental Margin ◽

Source Area ◽

Source Rocks ◽

Central China ◽

Clastic Rocks ◽

Ree Distribution ◽

C Value ◽

Tectonic Settings ◽

Jianghan Basin

Abstract This paper intends to learn about the provenance, tectonic setting and paleoenvironment of the Paleocene Shashi Formation in the southern Jianghan Basin by the bulk-rock geochemistry. The K2O/Al2O3 and SiO2/Al2O3 ratios indicate that the major proportion of samples are litharenite. The chondrite-normalized REE distribution pattern of the Shashi Formation’s mudstones are characterized by enriched LREE and flat HREE similar to those of UC with negative Eu anomalies. Combined with the geochemical element ratio discriminant diagram, such as Al2O3-TiO2, Zr-TiO2, La/Sc-Co/Th, and Hf-La/Th, so on, these samples were sourced from mixed felsic/basic rock. Moreover, the discriminant diagrams of K2O/Na2O-SiO2/Al2O3, La-Th-Sc, and Th-Co-Zr/10 suggest that the samples were formed under the tectonic settings of active continental margin and continental island arc. The values of CIA, CIW, PIA, ICV, Zr/Sc-Th/Sc, and ternary diagrams of A-(CN)-K and Al2O3-Zr-TiO2 indicate that weathering in the source area was weak and source rocks have not been reformed by depositional recirculation and hydraulic sorting. And the palaeoenvironmental indicators of C-value, Ni/Co, V/Cr, V/(V+Ni) and Sr/Cu, Ga/Rb indicate that the climate was cool and arid during the evaporite deposition period in the southern Jianghan Basin, and the water was in the condition of oxidation.

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Geochemistry of metasedimentary rocks of the Proterozoic Xingxingxia complex: implications for provenance and tectonic setting of the eastern segment of the Central Tianshan Tectonic Zone, northwestern China

Canadian Journal of Earth Sciences ◽

10.1139/e05-011 ◽

2005 ◽

Vol 42 (3) ◽

pp. 287-306 ◽

Cited By ~ 31

Author(s):

Qiugen Li ◽

Shuwen Liu ◽

Baofu Han ◽

Jian Zhang ◽

Zhuyin Chu

Keyword(s):

Tectonic Setting ◽

Active Continental Margin ◽

Northwestern China ◽

Geochemical Data ◽

Isotopic Study ◽

Tectonic Zone ◽

Elemental Ratios ◽

Chemical Index ◽

Eastern Segment ◽

Chemical Index Of Alteration

The eastern segment of the Central Tianshan Tectonic Zone in northwestern China includes the Proterozoic metasedimentary Xingxingxia complex. Because these rocks have been extensively deformed and metamorphosed to greenschist or amphibolite facies, a geochemical and Nd isotopic study was undertaken to constrain their provenance and tectonic setting, as well as to evaluate the effects of weathering and sedimentary processes on the source rock signature. Major- and trace-element data indicate that these samples are characterized by negative Eu anomalies, low chemical index of alteration values, and high index of compositional variability values. Chemical index of alteration values and the plot of molecular proportions Al2O3(CaO* + Na2O)K2O suggest low degrees of weathering of the source. They are compositionally immature and poorly sorted. Geochemical data and immobile elemental ratios, for example Al2O3/TiO2, Cr/Th, Eu/Eu* and (La/Yb)n, indicate that the clastic materials were derived predominantly from felsic sources. Sedimentary tectonic discrimination diagrams demonstrate that most of the samples of the Xingxingxia complex were deposited on an active continental margin or continental island-arc setting. Rare-earth element distributions, εNd(t) values (calculated at 1.20 Ga, varying from 3.00 to +6.1), TDM model ages (ranging from 1.30 to 2.30), and t εNd(t) plot, indicate that sediments of the Proterozoic Xingxingxia complex were derived from varying degrees of mixing between Paleoproterozoic crust and juvenile materials with the former predominating. There is an increased flux of juvenile materials from Weiya in the east through Dikar to Kumishi. The secondary juvenile source may be 1.2 Ga arc-magma materials.

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Constraining sources and relative flow rates of bottom waters in the Late Cretaceous Pacific Ocean

Geology ◽

10.1130/g47197.1 ◽

2020 ◽

Vol 48 (5) ◽

pp. 509-513 ◽

Cited By ~ 5

Author(s):

Shannon J. Haynes ◽

Kenneth G. MacLeod ◽

Jean-Baptiste Ladant ◽

Andrew Vande Guchte ◽

Masoud A. Rostami ◽

...

Keyword(s):

Ocean Circulation ◽

Deep Water ◽

Deep Convection ◽

Source Region ◽

Source Area ◽

Geochemical Data ◽

Deep Water Formation ◽

The North ◽

Water Formation ◽

Bottom Waters

Abstract Geochemical data suggest that ocean circulation patterns changed over a period of long-term cooling during the last 10 m.y. of the Cretaceous (late Campanian–Maastrichtian). Proposed changes include enhanced deep-water formation in the South Atlantic and/or Indian sectors of the Southern Ocean, initiation or enhanced deep-water formation in the North Atlantic, and alternating regions of deep convection in the North and South Pacific. Existing geochemical data do not allow simple confirmation or rejection of any of these scenarios. To test Pacific circulation during the Maastrichtian, we measured neodymium isotopic (εNd) values from four Pacific Deep Sea Drilling Project and Ocean Drilling Program sites and compare results both to Earth system model simulations using Maastrichtian paleogeography and to previous studies. Pacific εNd results consistently show a small negative εNd excursion during a well-documented, ∼1–3 m.y. early Maastrichtian cooling pulse (EMCP) but no other consistent trends across the late Campanian–late Maastrichtian interval (∼10 m.y.). Model results show that different CO2 forcings lead to changes in rates, but not patterns, of circulation. These combined results support the existence of a sustained source region for intermediate and deep waters in the southwestern Pacific throughout the late Campanian–Maastrichtian and indicate that changes in εNd values during the EMCP reflect an increased rate of overturning in the Pacific rather than changes in the source area of Pacific bottom waters.

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Sandstone petrography and geochemistry of the Nayband Formation (Upper Triassic, Central Iran): Implications for sediment provenance and tectonic setting

Austrian Journal of Earth Sciences ◽

10.17738/ajes.2019.0002 ◽

2019 ◽

Vol 112 (1) ◽

pp. 20-41 ◽

Cited By ~ 2

Author(s):

Asghar Etesampour ◽

Asadollah Mahboubi ◽

Reza Moussavi-Harami ◽

Nasser Arzani ◽

Mohammad Ali Salehi

Keyword(s):

Tectonic Setting ◽

Active Continental Margin ◽

Source Area ◽

Major Elements ◽

Upper Triassic ◽

Late Triassic ◽

Sediment Provenance ◽

Provenance Areas ◽

Nayband Formation ◽

Southwestern Margin

AbstractThe Upper Triassic (Norian–Rhaetian) Nayband Formation is situated at the southwestern margin of Central East Iranian Microcontinent and records Eo-Cimmerian events. The formation is composed of mixed carbonate-siliciclastic deposits. This study presents information on the tectonic reconstruction and palaeoclimate of the southwestern margin of Central East Iranian Microcontinent during the Late Triassic. Petrography and modal analyses of sandstones show a variety of quartz-rich petrofacies including subarkose, lithic arkose, sublitharenite, feldspathic litharenite and litharenite. The combined modal analysis and geochemical results of major and trace elements of the sandstone samples represents mixed sedimentary, intermediate, felsic igneous rocks and moderate- to high-grade metamorphic provenance areas. The major elements and modal analyses of the Nayband Formation sandstone samples suggest an active continental margin tec-tonic settings. The palaeoclimatic conditions were sub-humid to humid with relatively low to moderate weathering in the source area which is in agreement with the palaeogeography and palaeotectonic history of southwestern margin of Central East Iranian Microcontinent during the Late Triassic.

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Geochemical and Petrographical Characteristics of the Madzaringwe Formation Coal, Mudrocks and Sandstones in the Vele Colliery, Limpopo Province, South Africa: Implications for Tectonic Setting, Provenance and Paleoweathering

Applied Sciences ◽

10.3390/app11062782 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2782

Author(s):

Elelwani Denge ◽

Christopher Baiyegunhi

Keyword(s):

Tectonic Setting ◽

Active Continental Margin ◽

Sedimentary Rocks ◽

Source Area ◽

Granite Gneiss ◽

Major Elements ◽

Limpopo Province ◽

Source Areas ◽

Mgo Support ◽

Chemical Index Of Alteration

The sedimentary rocks of the Madzaringwe Formation in the Tuli Basin have been investigated using geochemical and petrographic methods to reveal their source area composition, tectonic setting, provenance and paleoweathering conditions. The petrographic studies show that the rocks consist mostly of clay minerals and quartz. The major elements geochemistry indicates that the rocks of the Madzaringwe Formation have the same source area. Based on the discriminant function plots, it can be inferred that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The binary plots of TiO2 versus Zr and La/Sr against Th/Co shows that the rocks were derived from silicic or felsic igneous rocks. The tectonic setting discrimination diagrams of SiO2 against Log (K2O/Na2O), Th–Sc–Zr/10, and TiO2 versus (Fe2O3 + MgO) support passive-active continental margin settings of the provenance. The A–CN–K (Al2O3–CaO + Na2O–K2O) ternary diagram and binary plot of the index of compositional variability (ICV) against chemical index of alteration (CIA) shows that the rocks have been subjected to moderate to intensive weathering. Geochemical and petrographic characteristics of the rocks point to uplifted basement source areas predominantly composed of sedimentary rocks and/or granite-gneiss rocks. These source areas might have been from adjacent areas near the Tuli coalfield which include the Limpopo Belt (igneous and sedimentary rocks), and basement uplifted rocks of the Beit-Bridge Complex, consisting of the granite, granite-gneisses and schists.

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Detrital zircon geochronology and provenance of Devono-Mississippian strata in the northern Canadian Cordilleran miogeoclineThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh.Northwest Territories Geoscience Office Contribution 0047. Geological Survey of Canada Contribution 20100432.

Canadian Journal of Earth Sciences ◽

10.1139/e10-056 ◽

2011 ◽

Vol 48 (2) ◽

pp. 515-541 ◽

Cited By ~ 26

Author(s):

Yvon Lemieux ◽

Thomas Hadlari ◽

Antonio Simonetti

Keyword(s):

Detrital Zircon ◽

Inductively Coupled Plasma ◽

Source Region ◽

Upper Devonian ◽

Detrital Zircons ◽

Detrital Zircon Geochronology ◽

Inductively Coupled ◽

Arctic Alaska ◽

Wide Range ◽

Late Neoproterozoic

U–Pb ages have been determined on detrital zircons from the Upper Devonian Imperial Formation and Upper Devonian – Lower Carboniferous Tuttle Formation of the northern Canadian Cordilleran miogeocline using laser ablation – multicollector – inductively coupled plasma – mass spectrometry. The results provide insights into mid-Paleozoic sediment dispersal in, and paleogeography of, the northern Canadian Cordillera. The Imperial Formation yielded a wide range of detrital zircon dates; one sample yielded dominant peaks at 1130, 1660, and 1860 Ma, with smaller mid-Paleozoic (∼430 Ma), Neoproterozoic, and Archean populations. The easternmost Imperial Formation sample yielded predominantly late Neoproterozoic – Cambrian zircons between 500 and 700 Ma, with lesser Mesoproterozoic and older populations. The age spectra suggest that the samples were largely derived from an extensive region of northwestern Laurentia, including the Canadian Shield, igneous and sedimentary provinces of Canada’s Arctic Islands, and possibly the northern Yukon. The presence of late Neoproterozoic – Cambrian zircon, absent from the Laurentian magmatic record, indicate that a number of grains were likely derived from an exotic source region, possibly including Baltica, Siberia, or Arctic Alaska – Chukotka. In contrast, zircon grains from the Tuttle Formation show a well-defined middle Paleoproterozoic population with dominant relative probability peaks between 1850 and 1950 Ma. Additional populations in the Tuttle Formation are mid-Paleozoic (∼430 Ma), Mesoproterozoic (1000–1600 Ma), and earlier Paleoproterozoic and Archean ages (>2000 Ma). These data lend support to the hypothesis that the influx of sediments of northerly derivation that supplied the northern miogeocline in Late Devonian time underwent an abrupt shift to a source of predominantly Laurentian affinity by the Mississippian.

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Origin of the Ordovician Mansehra granite in the NW Himalaya, Pakistan: constraints from Sr–Nd isotopic data, zircon U–Pb age and Hf isotopes

Geological Society London Special Publications ◽

10.1144/sp481.5 ◽

2018 ◽

Vol 481 (1) ◽

pp. 277-298 ◽

Cited By ~ 2

Author(s):

Masatsugu Ogasawara ◽

Mayuko Fukuyama ◽

Rehanul Haq Siddiqui ◽

Ye Zhao

Keyword(s):

Granitic Magma ◽

Geochemical Data ◽

Large Contribution ◽

Crustal Material ◽

Sr Isotope ◽

Nw Himalaya ◽

Nd Isotope ◽

Isotope Data ◽

Late Neoproterozoic ◽

T Values

AbstractThe Mansehra granite in the NW Himalaya is a typical Lesser Himalayan granite. We present here new whole-rock geochemistry, Rb–Sr and Sm–Nd isotope data, together with zircon U–Pb ages and Hf isotope data, for the Mansehra granite. Geochemical data for the granite show typical S-type characteristics. Zircon U–Pb dating yields 206Pb/238U crystallization ages of 483–476 Ma. The zircon grains contain abundant inherited cores and some of these show a clear detrital origin. The 206Pb/238U ages of the inherited cores in the granite cluster in the ranges 889–664, 1862–1595 and 2029 Ma. An age of 664 Ma is considered to be the maximum age of the sedimentary protoliths. Thus the Late Neoproterozoic to Cambrian sedimentary rocks must be the protolith of the Mansehra granitic magma. The initial Sr isotope ratios are high, ranging from 0.7324 to 0.7444, whereas the εNd(t) values range from −9.2 to −8.6, which strongly suggests a large contribution of old crustal material to the protoliths. The two-stage Nd model ages and zircon Hf model ages are Paleoproterozoic, indicating that the protolith sediments were derived from Paleoproterozoic crustal components.

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On the volcanic architecture, petrology and geodynamic setting of the 3.48 Ga Barberton komatiite suite, South Africa

South African Journal of Geology ◽

10.25131/sajg.124.0036 ◽

2021 ◽

Author(s):

E.G. Grosch ◽

J. Slama

Keyword(s):

South Africa ◽

Mantle Plume ◽

Source Region ◽

Crustal Contamination ◽

Primitive Mantle ◽

Geochemical Data ◽

Geodynamic Setting ◽

Crustal Material ◽

Type Section ◽

Formation Type

Abstract This study presents new field and petrological observations combined with geochemical data on a range of komatiitic to tholeiitic volcanic rocks from the ca. 3.48 Ga mid-lower Komati Formation type-section of the Barberton Greenstone Belt, South Africa. A range of mafic-ultramafic rocks is identified across a 1.44 km profile, leading to the proposition of a new preliminary volcanic architecture for the mid-lower Komati Formation type-section. Major, trace and rare earth element (REE) data in conjunction with Lu-Hf isotopic constraints indicate that the tholeiites, newly recognized high-magnesium basalts, basaltic komatiites and komatiites in the volcanic sequence have a primitive mantle signature with no geochemical affinity to Archaean or modern-day supra-subduction zone boninites. The whole rock initial εHf values of spinifex and massive komatiite flows in the lowermost part of the Komati type-section are negative, ranging between -1.9 and -3.1, whereas the second overlying spinifex and massive flow unit records positive initial εHf values between +0.5 and +4.7. A new geodynamic model involving crustal contamination of the mafic-ultramafic lavas is proposed for the Barberton mid-lower Komati Formation type-section, involving mantle plume-crust interaction. The new observations and data indicate that the komatiites erupted as a result of a mantle plume from a hot (>1 600oC) mid-Archaean mantle, in which the earliest volcanic flows were variably affected by crustal contamination during their ascent and eruption. The possibility of incorporation of lower crustal material and/or recycled crust residing in the mantle source region cannot be excluded. This indicates that modern-style plate tectonic processes, such as subduction, may not have been a requirement for the formation of the 3.48 Ga Barberton komatiite suite, with implications for the hydration state, geodynamic processes and secular thermal evolution of the Archaean mantle.

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The petrochemistry of the Lower Proterozoic metamorphic rocks from the Dabieshan-Lianyungang area, the southeastern margin of the North China Platform

Mineralogical Magazine ◽

10.1180/minmag.1991.055.379.15 ◽

1991 ◽

Vol 55 (379) ◽

pp. 263-276 ◽

Cited By ~ 3

Author(s):

Sang Longkang

Keyword(s):

Continental Margin ◽

North China ◽

Active Continental Margin ◽

The South ◽

North China Platform ◽

The North ◽

Lower Proterozoic ◽

Southeastern Margin ◽

Tectonic Settings ◽

North China Plate

AbstractBased on geological studies, 141 rock analyses and 5 trace element analyses of metabasites, the present paper deals with the rock association, chemical features, protolith formation and the original tectonic settings upwards through the Lower Proterozoic metamorphic strata in the Dabieshan-Lianyungang area, in the south-east of the North China Platform. The results of the study indicate that the lower and middle parts of the metamorphic strata comprise terrigenous clastics, phosphoritic and aluminous sedimentary formations which formed under stable continental margin conditions. In the middle-upper part a calc-alkaline volcano-sedimentary formation under the active continental margin was developed. The Lower Proterozoic meta-strata of sedimentary-volcanosedimentary origin from bottom upwards suggest that the tectonic evolution of the south-eastern margin of the North China Platform is a process from stabilization to mobilization. This process suggests a northward subduction of the Yangtze Plate under the North China Plate during the later part of the early Proterozoic.

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Early Cretaceous redbeds from the Minle Basin, Hexi Corridor, northwest China: Mineralogy and geochemistry implications for paleoweathering, provenance, and tectonic settings

Interpretation ◽

10.1190/int-2018-0120.1 ◽

2019 ◽

Vol 7 (2) ◽

pp. T525-T545

Author(s):

Yaxiong Sun ◽

Wenlong Ding ◽

Yang Gu ◽

Gang Zhao ◽

Siyu Shi ◽

...

Keyword(s):

Early Cretaceous ◽

Lower Cretaceous ◽

Chemical Weathering ◽

Tectonic Setting ◽

Active Continental Margin ◽

Northwest China ◽

Hexi Corridor ◽

Sediment Supply ◽

Compositional Variation ◽

Tectonic Settings

Redbeds with a large thickness in the lower Cretaceous record abundant geologic information in the Minle Basin. We have conducted the paleoweathering conditions, provenance, and tectonic settings based on mineralogy and geochemistry. Our results indicate that mudstone samples are characterized by abundant illite with negligible amounts of K-feldspars and analcime. The lower part of the lower Cretaceous is rich in quartz, whereas the upper part is dominated by dolomite and analcime. We suggest that this is caused by the decreasing input of the clastic influx during the middle-late early Cretaceous. High index of compositional variation values (average 1.33) indicate first-cycle sediment supply, suggesting an overall compositional immaturity and short-distance transportation. These characteristics are consistent with an active regional extension tectonic setting. The [Formula: see text] system ([Formula: see text];[Formula: see text];[Formula: see text]) and Th/U versus Th consistently reveal that the lower Cretaceous experienced a positive gradient in chemical weathering from young to old formations. Although the patterns of trace elements in three formations of the lower Cretaceous are different, those of the rare earth elements (REEs) tend to be consistent. The significant enrichment of light REEs, heavy REEs fractionation, and distinctive negative Eu anomalies suggest derivation from an old, upper continental crust composed of predominantly felsic sediments. This interpretation is supported by several discrimination diagrams such as titanium dioxide-nickel ([Formula: see text]), which shows the characteristics of immature recycled sediments. A few sensitive elements, ratios, and normalized REE patterns indicate a provenance of an active continental margin and a continental island arc (CIA). The La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 discrimination plots further confirm the CIA signature. Thus, we conclude that the early Cretaceous redbeds in the Minle Basin, Hexi Corridor, were deposited in a dustpan-shaped half-graben basin in a CIA setting when northwest China was influenced by intense regional extension.

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