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This paper studies the major, trace, and rare earth elements (REEs) in fluvial sediments from the Yarlung Zangbo River (YZR) on the Tibetan Plateau, China, with the aim of investigating their provenances, sediment maturity, weathering conditions, and tectonic settings. All samples and analytical techniques are based on Environmental Geochemical Monitoring Networks, which are a crucial part of IGCP259/360 (Global Geochemical Baseline). The results show that the YZR sediments consist of greywacke and litharenite with low‐moderate maturities of textures and minerals. The chemical index of alteration (CIA) (49–71), plagioclase index of alteration (49–77), and index of compositional variability (ICV) values (0.82–1.54) indicate that both mature and immature sediments are present in the YZR and have experienced weak to moderate weathering with little intense weathering in the source area, which is also confirmed by the ICV‐CIA, A‐CN‐K, A‐CNK‐FM, and MFW plots. Moreover, the provenance discrimination diagrams suggest that the YZR sediments are predominantly derived from felsic rocks that are close to the upper continental crust and from acid intermediates, and the tectonic settings of the YZR source rocks were associated with active continental margins and continental island arcs. The overall sediment types, weathering conditions, and tectonics of the YZR were consistent with those of the Brahmaputra River and Meghna River during the Himalayan–Tibetan orogeny, while the sediments of the Brahmaputra River are characterized by recycled‐quartzose sources when compared with the other two Himalayan rivers due to the contributions of quartzolithic composition. [ABSTRACT FROM AUTHOR]

The Lower Jurassic clastic rocks in the Qiangtang Basin, northern Tibet, are generally regarded as the early sediments of the new Mesozoic Qiangtang Basin (Late Triassic to Early Cretaceous). However, little attention has been paid to the palaeoenvironment, provenance, and tectonic setting of this unit. The QZ‐16 well, located in the east of the northern Qiangtang Basin, firstly recovered the Lower Jurassic strata (Quemo Co Formation) in the Qiangtang Basin. In this paper, the whole‐rock major‐trace elemental characteristics of 34 mudstone samples and detrital zircon geochronology of one sandstone, collected from the Quemo Co Formation of the QZ‐16 well, are reported in order to infer the palaeoenvironment, provenance, and tectonic setting. Quemo Co mudstones are dominated by SiO2 and Al2O3, while Fe2O3, CaO, K2O, and MgO are the second most abundant oxides. They are generally characterized by high REE concentrations, enrichment in light rare earth elements (LREEs), marked negative Eu and Ce anomalies. The REE contents of the mudstones are mainly controlled by terrigenous detrital minerals input. The Lower Jurassic mudstones have relatively high chemical index of alteration (79.1–83.6) values, indicating moderate to high degree of chemical weathering conditions of the source area. Sr/Ba and Rb/K ratios reflect that the marine transgression impact was limited and the mudstones were generally deposited in a brackish water environment. Major, trace, and REE contents indicate that the mudstones were mainly derived from intermediate igneous rocks with subordinate felsic igneous rocks. Prominent age peaks at ca. 200 ~ 400 Ma, 700 ~ 970 Ma, 1,700 ~ 1,900 Ma, and 2,100 ~ 2,700 Ma of the detrital zircon grains suggest that the Lower Jurassic clastic rocks were derived from the Central Qiangtang and Songpan–Ganzi complex. Moreover, tectonic discrimination diagrams based on major and trace elements show that the source of the Lower Jurassic sediments were most likely derived from a collision tectonic setting. [ABSTRACT FROM AUTHOR]

Oil-source correlation studies have demonstrated that the crude oils in the Ordos Basin were mainly derived from organic-rich lacustrine mudstones of the Yanchang Formation. The sedimentology, petrology and organic geochemistry of these mudstones have been studied intensively, but their trace and rare earth element (REE) characteristics have received little attention. In this paper, we present trace and rare earth element data of the Upper Triassic Yanchang Formation mudstones in the southern Ordos Basin to constrain the palaeoenvironment, provenance and depositional setting. Our results show that the REE and trace element concentrations of the Yanchang Formation mudstones are higher than those of the upper continental crust (UCC). The Sr contents and Sr/Ba and Y/Ho ratios of these mudstones indicate the absence of a marine transgression during the sedimentation of the Upper Triassic mudstones. The depositional environment of the Upper Triassic mudstones was slightly oxic as evidenced by the values of Eu/Eu*, Ce/Ce*, Ceanom, δU, U/Th, V/Cr and Ni/Co. The UCC-normalized distribution pattern of REEs, spider diagrams, the ratios of related elements, the bivariate diagrams of Th/Sc-Zr/Sc and La/Th-Hf and the ternary plots of La-Th-Sc and Th-Sc-Zr/10 signify that the provenances of the Chang9-7 mudstones were mainly derived from a continental island arc, whereas the provenances of the Chang6-3 mudstones were mainly derived from a mixture of continental island arc and active continental margin, and the latter contain less recycled materials. Combined with the previous studies of detrital zircon dating and petrography of the Yanchang Formation sandstones in the southern Ordos basin, we propose that the Qinling orogenic belt served as one of the primary source regions occurring between the Chang7 and Chang6 periods, corresponding to the initial uplift of the west Qinling Mountains due to the collision between the Yangtze and North China blocks. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Late Permian Sunjiagou Formation and Early Triassic Liujiagou Formation were studied to understand the palaeoclimatic and palaeoenvironmental changes in the southwest margin of the North China Craton across the Permian–Triassic boundary, as well as the tectonic evolution of their provenance sediment. Major, trace, and rare earth elements in 20 clastic rock samples from the strata above and below the boundary were analysed. Overall, the Sunjiagou Formation samples showed an average index of compositional variability (ICV) and chemical index of alteration (CIA) of 1.53 and 73.59, respectively, indicating high‐maturity sediments in a warm and humid environment with moderate chemical weathering, whereas Liujiagou Formation samples had an average ICV and CIA of 2.40 and 70.1, respectively, indicating low‐maturity sediments in a cold and dry environment with mild chemical weathering. These strata were composed of first‐cycle sediments in a tectonically active area. The provenance of the Sunjiagou Formation was dominated by quartz‐rich sedimentary rocks, whereas that of Liujiagou Formation had both quartz‐rich sedimentary rocks and intermediate volcanic rocks. The provenance tectonic settings were mainly the continental island arc and active continental margin. Thus, the study area was in a terrestrial, freshwater sedimentary environment from the Late Permian to Early Triassic, and the climate gradually changed from warm and humid to dry and hot, with multiple small‐scale periodic evolutions. Taken together, these findings further confirm that the entire study area was in an oxidizing environment and the oxidation degree in the Early Triassic was higher than that in the Late Permian. [ABSTRACT FROM AUTHOR]

The mineralization in this area is more closely related to the shoshonitic Niuxinshan meddling complex (NIC), which helps to depict concurrent edge magmatism metallogeny. In the present investigation, new geochronological and geochemical data are combined with previously disseminated isotopic data from granitic rocks in the NIC to establish the situation of the region's structural setting change and determine its bearing on territorial metallogeny. The new geochronological data suggest that structural change could have occurred between 155 and 185 Ma. The granitic rocks of the NIC can be geochemically divided into two groups. The geochemical signature of one group displays high rare earth element (REE) designs with irrelevant Eu anomalies, lower Yb, higher Sr, and negative Nb–Ta–Ti (NTT) abnormalities, demonstrating a volcanic‐curve climate with a thickened outside layer in a focalized setting. The other group has level REE designs with obvious regrettable Eu anomalies, higher Yb, lower Sr, and moderate NTT anomalies, indicating an intra‐plate extensional climate with a decreasing outside. According to geochronologic and isotopic data, the mineralization is Late Jurassic (155 Ma). This has been deciphered to be hereditarily associated with the crystallization of the complex's shallow crustal‐sourced bits. In addition, a structural model is presented that provides a possible explanation for the abundant polymetallic mineralization that occurs in the northern margin of the NCC after 155 Ma. [ABSTRACT FROM AUTHOR]

The sandstones of Upper Miocene Injana Formation were studied petrographically and geochemically in the Hemrin South Mountain area, northern Iraq. The sandstones vary between arkose and lithic arkose in composition (Q50F24L26) and are compositionally and texturally immature; meanwhile, the Log(Fe2O3/K2O)–Log(SiO2/Al2O3) diagram shows that they are divided between arkose, litharenite and wacke. These sandstones contain a wide spectrum of heavy minerals ranging from the most resistant ultrastable minerals (zircon, rutile and tourmaline), to the least resistant non‐stable minerals (amphiboles and pyroxenes). The provenance indicator diagrams QmFLt and QtFL indicate multi‐sources for these sandstones ranging from transitional craton, arc and recycled sediments. The major element provenance discriminant function plot shows that they are derived mostly from intermediate igneous provenance. All these suggest that the probable source of these sandstones is the igneous‐metamorphic rocks including the ophiolites of the Suture Zone, the imbricate zone, the Shalair‐Sanandaj‐Sirjan Terrane and the complimentary rock units in Turkey and Iran. The presence of glaucophane as the provenance indicator mineral for subduction zones is a further proof of the ophiolites having acted as the source rocks. Geochemically, the sandstones are enriched in Ca, V, Cr, Ni, Cu, Mo, Sn and Sb and depleted in all othe major, trace and rare earth elements (REE) relative to upper continental crust (UCC). The chondrite‐normalized REE pattern shows a distinct negative slope for the LREEs and a slight negative slope for the HREEs with an enrichment of LREE/HREE of 8.11–10.90 and a negative Eu anomaly of 0.70–0.83. The most probable source of REEs is the heavy minerals detected in the sandstones. Tectonically, the studied rocks were derived from collision rifting arc–related settings. The Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA) and Index of Composition Variation (ICV) values of the Injana sandstones suggest that they are compositionally immature and suffered from very weak weathering indicating the proximity of their source rocks and their deposition under dry continental conditions. [ABSTRACT FROM AUTHOR]

Detrital mineralogy, major oxides, trace, and rare earth elements (REE) were examined in the Middle Jurassic Fort Member Sandstone (FMS) of the Jaisalmer Formation in Western India to understand palaeoweathering, provenance of sediments, and to decipher the tectonic setting. The sandstones are classified as arkose to sub‐litharenite types according to their relative percentages of quartz, feldspar, and lithic fragments, and major elemental ratios. The values of Chemical Index of Alteration (67–85), Plagioclase Index of Alteration (78–97) and Chemical Index of Weathering (83–97) along with A‐CN‐K diagram suggest moderate to intense chemical weathering in the source region. Presence of fresh feldspars and dominance of monocrystalline quartz, showing both parallel and undulose extinction, indicate plutonic and volcanic felsic igneous provenance. Contribution from metamorphic orogen sources is indicated by the lithic fragment population. Various geochemical parameters such as Th/Sc, Cr/Th, Ti/Zr, and Eu/Eu* support a dominant felsic provenance. Higher Zr/Sc ratios relative to the magmatic Zr/Sc‐Th/Sc trend, higher Zr and Hf concentrations in the FMS indicate some extent of sedimentary recycling and zircon sorting. LREE enrichment, flat HREE pattern, negative Eu anomaly and trace element ratios, in conjunction with palaeocurrent data, indicate a likely sediment contribution from basement source terrains including Erinpura‐Mount Abu‐Sirohi granites, Malani Igneous Suite, and Aravalli‐Delhi orogens. The major and trace element tectonic setting discrimination diagrams for the FMS indicate a passive margin setting. [ABSTRACT FROM AUTHOR]

The depositional environment and sediment provenance of the third member of Palaeogene Shahejie Formation (Es3) in the Nanpu Sag of the Bohai Bay Basin, eastern China, are reconstructed by analysing trace element and rare earth element (REE), and the formation mechanism of organic‐matter‐rich shales of the same member is also evaluated. These results show that the terrigenous detrital supply in the Nanpu Sag was relatively sufficient during the Es3 interval, and the total REE contents range from 148.23 to 319.28 ppm, close to or higher than that of the upper crust. The Sr concentrations are 214.22–525.54 ppm and the Sr/Ba ratios are 0.31–0.74, which represent the coexistence of fresh, brackish, and saline waters during the Es3 interval. The V/(V + Ni) ratios of 0.71–0.82, Th/U ratios of 0.82–4.05, and positive δCe anomaly confirm that the water column was suboxic condition, with moderate stratification during the Es3 interval. Comparison of REE behaviours suggests that the Es3 sediments were primarily derived from Yanshanian granites at the Yanshanian fold belt at the active continental margin. The development of organic‐matter‐rich shales in the Es3 member in the Nanpu Sag was closely related to major palaeoenvironmental and palaeogeographical variations in that time, which can be summarized: (a) suitable palaeosalinity as well as sufficient nutrients in water column contributed to the boom of various planktonic algae, improving the production efficiency of aquatic organic matter; (b) suboxic water column slowed down the degradation of oxygen‐sensitive materials during the burial process, enhancing the preservation efficiency of aquatic organic matter. [ABSTRACT FROM AUTHOR]

The earliest record of Himalayan detritus in the Himalayan foreland and the erosion sequence of different lithotectonic units of the Himalaya are critical for reconstructing collision and crustal deformation of the orogenic belt. In this study, bulk‐rock major, trace and rare earth elements of 19 fine‐grained clastic sedimentary rock samples from Eocene to Pliocene strata of the Bengal Basin were examined to study their provenance and erosion of the Himalaya. Combining with previous detrital zircon age data from the Bengal Basin, Nepal foreland basin, and South Tibet, we suggest that detritus from the uplifted Tethyan Himalayan Sequences and the Gangdese Arc had not been carried into the Himalayan foreland at least before Late Miocene, and that the Bengal Basin was in a passive continental margin setting from Eocene to Early Miocene, receiving detritus from a felsic sedimentary rock source. The earliest Himalayan detritus recorded in the Eocene strata of Bengal Basin were probably derived from the antecedent sedimentary cover of the Greater Himalayan crystalline rocks. We assume that the lack of Cretaceous Gangdese detritus in the Himalayan foreland from Eocene to Middle Miocene is due to a geomorphic barrier between the Tethyan Himalaya and the Himalayan foreland. Detritus from the Greater Himalayan crystalline rocks were first recorded in the Middle–Late Miocene Boka Bil Formation of the Bengal Basin, which is consistent with the uplift and exhumation time of the Greater Himalayan Sequences. [ABSTRACT FROM AUTHOR]

The whole‐rock geochemistry and Sr‐Nd isotope data of Middle Jurassic sedimentary rocks in the Gümüşhane area (north‐eastern Turkey) were analysed to reconstruct the provenance, chemical weathering, sediment recycling history, and tectonic setting of the source area. Based on trace element ratios and rare earth element (REE) patterns, it was interpreted that the sandstones were derived from a source area with felsic‐mafic rocks as dominant contributors. The average chemical index of alteration (CIA) and weathering index (WIP) values are low with respect to Upper Continental Crust (UCC) in the studied sandstones and mudstones, but the index of compositional variability (ICV) values are high, thus revealing weak–moderate weathering conditions. The average Th/U ratios of the sandstones and mudstones indicate a relatively simple cycling history. The positive and low negative εNd values support the supposition that the source area did not undergo much sedimentary change. A model mixture composed of 60% granite, 5% granodiorite, and 35% gabbro could be deduced to be the potential source composition of Middle Jurassic sediments; this model was reinforced by the 87Sr/86Sr ratios and εNd(t) values of the sediments. The Middle Jurassic siliciclastic sedimentary rocks of the Gümüşhane region were likely deposited in a tectonic environment with a passive margin. [ABSTRACT FROM AUTHOR]

The major, trace, and rare earth element (REE) compositions of sediments from the Meghna River in Bangladesh have been examined to infer their sediment type, compositional maturity, chemical weathering intensity, provenance, and tectonic setting. Geochemically, the sediments are classified as litharenites, shale, and wacke. The ICV (Index of Compositional Variability) values (0.92 to 1.10) indicate that the sediments have low compositional and mineralogical maturity. Major and trace element abundances display marked depletion of Na2O, CaO, MgO, K2O, Fe2O3T, Sr, and Ba relative to UCC (upper continental crust), suggesting loss of feldspars during chemical weathering in the source. Zirconium, Th, Ce, and Y are enriched relative to UCC, indicating that these elements are primarily controlled by resistant heavy minerals. The CIA (Chemical Index of Alteration), PIA (Plagioclase Index of Alteration), and Rb/Sr and K2O/Rb ratios of the river sediments suggest low to moderate intensity of chemical weathering in the source area. Chondrite‐normalized REE patterns show that high LREE enrichment, nearly flat HREE fractionation (LaN/YbN = 7.62 to 8.73) and marked negative Eu anomalies (Eu/Eu* = 0.49 to 0.69) suggesting a felsic source provenance. Several discriminant function diagrams and immobile trace element ratios (Th/Sc, Zr/Sc, Ce/Sc, and Ti/Zr) and REEs (∑LREE/HREE, Eu/Eu*, and GdN/YbN) parameters indicate that the river sediments were primarily derived from a common felsic source rock, with composition close to the average rhyolite, granodiorite, granite, and UCC. Tectonic setting signatures of the Meghna River sediments are both active continental margin and passive margin environments. [ABSTRACT FROM AUTHOR]

Detailed petrological, whole‐rock geochemical, and zircon Hf isotopic researches were conducted on the Late Carboniferous–Triassic sedimentary rocks in the Bogda region to evaluate the effects of weathering, sorting, and alteration, as well as to understand their provenance and tectonic setting. These rocks show variable major element compositions, but most are generally similar to post‐Archean Australian shales. The relatively narrow range of TiO2–Zr variation and good correlation between Th/Sc and Zr/Sc signify no obvious sorting and recycling of the sedimentary rocks. The relatively high index of compositional variability (0.8–3.1) and low chemical index of alteration values (44.4–76.4) of the sedimentary rocks indicate that they are immature and probably undergo weak to moderate chemical weathering. In the chondrite‐normalized diagrams, almost all the samples are distinguished by moderately enriched light rare earth element and flat heavy rare earth element patterns with negative Eu anomalies (Eu/Eu* = 0.5–0.8). In conjunction with their Th/Sc, Zr/Sc, La/Th, Zr/Al2O3, TiO2/Zr, Co/Th, and La/Sc ratios, we infer that the major sources of these sedimentary rocks were the intermediate–acidic igneous rocks from the North Tianshan and Yili–Central Tianshan. Combining the orientation of the Bogda region in the Palaeozoic that was roughly perpendicular to the Tianshan and/or East Junggar orogens with the sedimentologic, petrologic, and tectonic researches, we suggest that the Bogda region was a rift basin that occurs at high angles to the orogenic belt. On the other hand, the zircons from these sediments have minor Precambrian grains (<0.2%), positive εHf(t) values (mostly +7.1–+15.0) and young 2‐stage Hf model ages (major peak <1,000 Ma), suggesting that a juvenile continental crust exists as the basement of the Junggar Basin. The geochemical data reveal weakly to moderately weathering of the source, compositionally immature and poorly sorted.The rift model appears as the most likely geodynamic interpretation of the Bogda region.The juvenile continental crust exists as the basement of the Junggar Basin. [ABSTRACT FROM AUTHOR]