Sediment Provenance Research Articles

Provenance, diagenesis and reservoir quality of sandstone facies of the Maracangalha Formation, Recôncavo Basin – Northeastern Brazil

Sedimentary composition studies on siliciclastic reservoirs and their relationship with sedimentary provenance have proved to be useful in hydrocarbon exploration, enabling the prognosis of reservoir quality and diagenetic models. However, unconventional terrigenous reservoirs in the Maracangalha Formation, Upper Cretaceous from Recôncavo Basin, have not yet been evaluated regarding sedimentary provenance and its control over reservoir quality. This study aims to define the provenance of the Maracangalha Formation sandstones and its control on the diagenetic processes affecting the reservoir quality. Based on petrography analysis and X-Ray Fluorescence data, it was possible to identify a granite-gneissic terrain under wet climate as the primary source area for quartz-feldspathic sandstones. The granite-gneissic terrains with predominantly felsic minerals, within in the surrounding Precambrian Terrains, represent a major source area for the quartz-feldspathic sandstones found in the Maracangalha Formation. These sources are characterized by significant contributions from recycled sedimentary and metasedimentary rocks, leading to the occurrence of litho and quartzose petrofacies. The high chemical-textural sediment maturity and paleoweathering dispersion, under semi-umid to semi-arid climates, may be a result of paleoclimatic changes and the variable residence times of the sediments in the dispersion routes or temporary storage. The mineral composition and primary texture of sandstones show a clear influence on diagenetic evolution, particularly in terms of mechanical compaction inhibition, by early cementation, and the generation of secondary porosity due to the dissolution of framework grains and early cements. Therefore, understanding the sedimentary provenance, composition, and diagenesis is crucial for predicting the quality of the reservoir and the compartmentalization of the Maracangalha Formation and its analogues.

Dense mineral distribution in the northwestern Arabian Sea: insights into sediment provenance and paleoclimate

Dense mineral distribution in the northwestern Arabian Sea: insights into sediment provenance and paleoclimate

Paleogene sediment provenance in the Gaize Basin: Implications for early Cenozoic paleogeography of central Tibet

A comprehensive study of the sediment source-to-sink history of basins arranged along the Bangong-Nujiang Suture Zone (BNSZ) is critical for understanding the early Cenozoic topography and drainage systems of central Tibet and its implications for the uplift history of the Tibetan Plateau. Nevertheless, previous provenance analyses work mainly focused on the middle-eastern segment of the BNSZ, those Paleogene basins in the western segment have received less attention, which hinders a full understanding of the early Cenozoic topography of central Tibet. In this study, based on a chronostratigraphic framework developed for the lower Cenozoic continental redbeds of the Gaize Basin, we applied detrital zircon U-Pb geochronology to the well-exposed Paleogene Suonahu Formation in order to reconstruct the basin's source-to-sink history. Integrating these new data with detrital zircon U-Pb results from the underlying Kangtuo Formation, we recognize a major secular shift in sediment provenance characterized by inputs of Lhasa-derived clasts during the Late Eocene. Moreover, we applied statistical analysis to compare the U-Pb age spectra of Eocene strata in the Gaize-Nima-Lunpola basins in order to assess similarities between them and potential source regions. Our study confirms a paleogeographic scenario in which these Paleogene basins most likely were part of a low-elevation intermontane valley.

Detrital zircon U‐Pb geochronology and provenance of Silurian, Devonian and Permian sedimentary rocks, South Qinling: Constraints on late Palaeozoic tectonic evolution history of the Qinling Orogenic Belt

The Qinling Orogenic Belt (QOB), formed by the subduction and collision between the North China Block (NCB) and the South China Block (SCB), is a key area for exploring the tectonic process and timing of integration between the two blocks. A range of tectonic models have been proposed with regard to the subduction and collision of the QOB, but controversy in the timing and integration process still remain debatable, especially in the late Palaeozoic orogeny. The South Qinling Belt (SQB) is located between the Shangdan and Mianlue sutures, widely dispersed sediments outcropped in the SQB provide natural ground for the detrital zircon study, that could trace the sedimentary provenance and continental crustal evolution history, thus provide important evidence for the late Palaeozoic evolutionary processes in the QOB. In this study, we applied a detailed geochronological U‐Pb zircon dating of the Silurian, Devonian and Permian sedimentary rocks from the SQB. The result of the U‐Pb isotopic data shows distinct age populations at 439–474 Ma of the Silurian samples, ca. 400–490 Ma of the Devonian samples and 260–310 Ma of the Permian samples, respectively. By comparing the regional geochronological data, we sum up that the Silurian detrital zircons are mainly derived from the SQB and the northern margin of SCB (N‐SCB), the Devonian detrital zircon age populations are dominated by the North Qinling Belt (NQB) and SQB and the Permian sediments mainly stemmed from the southern margin of the North China Block (S‐NCB) and the NQB. A mutual age population of the Devonian sediments at ca. 400–490 Ma from the NQB constrains the closure of the Shangdan Ocean between the NCB and the SCB before the middle Devonian times. Ca. 260 ~ 380 Ma age population of the Permian sediments show similarities with the age data from the northern margin of the NCB, indicating an uplift event of NQB before the late Permian, and further constrains the closure of Mianlue ocean later than Permian times.

Spatio-temporal variation in quartz luminescence sensitivity in the coastal area of China

Quartz luminescence signals have been proven to be an effective index for identifying sediment provenance. The provenance of quartz minerals on typical sandy coasts along the east coast of China serves as important evidence for estuarine and coastal aeolian geomorphological processes in coastal zones. However, the temporal and spatial differences in the sensitivity characteristics of quartz grains on the east coast of China remain controversial owing to a lack of systematic analyses of coastal sediments. In this study, we present the thermoluminescence (TL) and optical luminescence (OSL) sensitivity of quartz minerals from core FN1 in the coastal area of Fujian Province, and the relative OSL sensitivity of quartz minerals obtained from Hebei, Fujian, Hainan, and Taiwan provinces. Our results indicate that (1) the OSL sensitivity values of quartz grains in the FN1 core are closely correlated with the mean grain size, electrical conductivity, potential of hydrogen, and end-member, suggesting that the change in luminescence sensitivity may be closely related to climate changes; specifically, cold climatic events during this period can cause significant fluctuations in the sensitivity; further, the percentage contents of fast, medium, and slow components are also different; (2) spatially, there are clear differences between the %FAST value of quartz grains from different sandy coasts; in these coastal dune samples, the %FAST value of the quartz grains during the Last Glacial Maximum (LGM) was significantly different from that of the quartz grains during the interglacial; thus, %FAST can be used to distinguish between glacial and interglacial samples; specifically, the sensitivity of quartz from the glacial dune was higher than that from the interglacial dune, and the sensitivity dispersion of quartz from the glacial as smaller than that from the interglacial coastal dune sand; and (3) the change in the luminescence sensitivity of quartz grains was ultimately controlled by the provenance change. In different geological periods, transgression, regression, and abrupt climate change trigger changes in the supply range of sources, which indirectly affects the sensitivity characteristics of quartz minerals. The spatial difference in quartz sensitivity in the eastern coastal area of China is mainly affected by the characteristics of quartz crystals and types of bedrock, which require further systematic study.

Impact of Mexican Border rift structural inheritance on Laramide rivers of the Tornillo basin, west Texas (USA): Insights from detrital zircon provenance

Abstract Late Cretaceous to Eocene Laramide basement–involved shortening fragmented the Sevier and Mexican foreland basins. This resulted in a major drainage reorganization in response to the emerging topography of Laramide basement–cored uplifts and Mexican inverted Border rift basins. This study presents new depth-profile detrital zircon U-Pb data (3679 ages from 28 samples) from Upper Cretaceous–Eocene fluvial strata of the Tornillo basin in west Texas to determine sedimentary provenance and reconstruct sediment dispersal through the U.S.-Mexico border region. Detrital zircon U-Pb data are dominated by Hauterivian–Coniacian (130–87 Ma; ~20%) and Coniacian–Ypresian (87–52 Ma; ~30%) ages that represent Cordilleran and Laramide arc magmatism, respectively. Subordinate age groups are Paleoproterozoic–Mesoproterozoic (1900–1300 Ma; ~12%), Ectasian–Tonian (1300–900 Ma; ~8%), Tonian–Pennsylvanian (900–300 Ma, ~10%); Permian–Triassic (300–200 Ma; ~8%), and Jurassic–Early Cretaceous (200–130 Ma; ~11%). Detrital zircon maximum depositional ages provide new constraints on the chronostratigraphic framework of the Tornillo Group, the stratigraphic nature of the Cretaceous-Paleogene boundary, and the stratigraphic level of the Paleocene–Eocene thermal maximum. Depth-profile core-rim age pairs yielded Paleoproterozoic–Mesoproterozoic and Jurassic cores with Cretaceous–Paleogene rims, which represent zircons derived from Laramide magmatic rocks that intruded Yavapai-Mazatzal basement and Cordilleran-Nazas magmatic rocks. Zircon grains with Ectasian–Tonian cores and Paleozoic rims likely represent Appalachian-derived and/or Coahuila terrane zircons recycled from the inverted Mesozoic Bisbee basin and Chihuahua trough. These results demonstrate that fluvial strata in the Tornillo basin were sourced from Laramide and Cordilleran magmatic rocks, Yavapai-Mazatzal basement, and recycled Mexican Border rift sedimentary rocks in the southwest United States and northern Sonora, and these sediments were delivered via a large (>103-km-long), axial-trunk river. Additional recycled detritus from Mexican Border rift sedimentary rocks in the Chihuahua fold belt was delivered via transverse tributaries. This drainage reconstruction indicates that the Tornillo river flowed along an inversion-flank drainage corridor adjacent to topography formed by the inverted Mexican Border rift. Therefore, inherited Mexican Border rift architecture represented a first-order control on sediment routing to the Tornillo basin.

U–Pb ages and paleoenvironmental evolution of the guanchín formation (neogene fiambalá foreland basin), Central Andes, Argentina

The Guanchín Formation is a sedimentary unit that was deposited during the Andean orogeny and is preserved in the Fiambalá Basin in NW Argentina. It records an advanced stage of the broken-foreland evolution in a transitional zone between the morphotectonic domains of the Precordillera, the Sistema de Famatina, the Western Sierras Pampeanas, and the southern Puna. Furthermore, it preserves a record of Late Miocene explosive volcanism that is common in all the foreland basins in this Andean segment. The Guanchín Formation was studied at Cuesta Loro Huasi and Guanchíncito sections, where seven facies associations (FA) were recognized. These represent ephemeral sandy braided fluvial systems with thin mud floodplains (FA1), sheetflow-dominated sandy-tuffaceous alluvial plain (FA2), perennial sandy braided fluvial system (FA3), fine-grained alluvial plain built up by unconfined flows and less terminal splays (FA4), sheetflow-dominated sandy alluvial plain (FA5), and sandy-gravelly (FA6) and sandy-dominated (FA7) braided fluvial system, arranged in chronological order from oldest to youngest. To date the formation, zircon U/Pb ages from tephras were obtained from the Cuesta Loro Huasi section, which yielded depositional ages of 6.10 ± 0.07, 5.89 ± 0.09, 5.60 ± 0.06, and 5.20 ± 0.05 Ma, while a fifth sample from the Guanchíncito section yielded an age of 3.26 ± 0.05 Ma. Additionally, detrital zircon analyses were performed to infer sediment provenance and constrain the maximum depositional age of sedimentary units. These data combined with paleoenvironmental analysis and clast compositions in conglomerates suggest that the Western Sierras Pampeanas had been uplifted around ∼6 Ma. By this time the drainage was dissipated as a distributary fluvial system (DFS) under semiarid climatic conditions, which received sediments from northern, eastern, and to a lesser extent from western sources. Around ∼3 Ma the basin started to receive coarse-grained sediments of braided fluvial systems (FA6 and 7) indicating a closer proximity to the Pampean sources areas. The Guanchín Formation records an overall progradational trend manifested through two minor progradational cycles, each one controlled by changes in the equilibrium profile and accommodation space of the basin. This trend is likely associated with a basinward increase in the subsidence rate or enhanced water availability in the headwaters, potentially linked to tectonic uplift in the eastern and/or northern ranges, including the final uplift of the southern Puna. Since previous works placed the deposition of the overlying Rodado de la Puna Formation deposition began at 4 Ma, these news ages suggest the top of the Guanchin Formation is younger than previously thought.

Detrital Zircon Geochronology and Provenance of Metasedimentary Rocks from the Susong Complex Zone in the Dabie Orogen

AbstractThe Susong complex zone is a relatively low‐grade metamorphic unit located in the southern part of the Dabie orogen and preserves a variety of metasedimentary rocks, mostly with epidote–amphibolite facies. However, their depositional age, provenance and tectonic setting of sedimentary protolith remain controversial due to the lack of fossils, precise dating and integrated geochemical investigation. This study has conducted whole‐rock elemental, and zircon U‐Pb SHRIMP dating and Lu‐Hf isotope analyses on three types of representative metasedimentary rocks including garnet‐bearing mica‐quartz schist, graphite‐muscovite‐quartz schist and dolomitic marble from the Susong complex zone. The U‐Pb SHRIMP dating data indicate that the sedimentary protolith of these rocks have the maximum depositional ages of less than 840–750 Ma and have various sedimentary provenances. In combination with zircon Lu‐Hf isotope compositions, the provenance of the metasedimentary rocks in the region is for the first time documented to be mainly derived from four groups of magmatic rocks formed at ∼2.5 Ga, ∼2.0 Ga, ∼1.4 Ga and ∼0.8 Ga in response to four episodes of igneous activity in the northeastern margin of the Yangtze Block. The conventional geothermobarometry combined with rare metamorphic zircon ages indicate that the studied rocks underwent the Late Triassic continental subduction‐related metamorphism with peak epidote–amphibolite facies conditions at P = 0.34–0.91 GPa and T = 427–532°C. In addition, results of the elemental contents (i.e., La, Ce, Th and ΣREE) and ratios (i.e., Eu/Eu* and LaN/YbN) suggest that the protoliths of the metasedimentary rocks were mainly shales, wackes and limestones, most probably related to the Rodinia supercontinent rifting along the northern margin of the Yangtze Block during the Neoproterozoic.

Tectonic-geomorphological evolution and provenance-sedimentary response: Insights from the Middle Jurassic–Lower Cretaceous, Junggar Basin, China

Understanding the complex depositional systems within lake basins requires a comprehensive analysis of the interplay between tectonic-geomorphological evolution and climate change. Based on three-dimensional seismic data, outcrops, well logging, cores, thin sections, and heavy mineral data, this study reconstructed the tectonic-geomorphological evolution of the Middle Jurassic–Lower Cretaceous in the Junggar Basin and analysed the responses of sequence stratigraphy, sediment provenance, and depositional systems. The Jurassic Xishanyao and Cretaceous Qingshuihe Formations developed third-order sequences (SQ1 and SQ2, respectively), which both consisted of lake transgressive (TST) and regressive system tracts (RST). During the SQ1 period, the Chepaizi-Mosuowan palaeo-uplift underwent substantial erosion and supplied sediment to the surrounding sub-basins, where deposited braided-river deltas were formed. Middle Yanshanian tectonism resulted in rapid subsidence, and the Chepaizi-Mosuowan palaeo-uplift submerged. During the early TST stage of SQ2, sediment from the northeast and northwest formed shallow braided-river deltas in topographic lows surrounding the residual Chepaizi-Mosuowan palaeo-uplift and reduced topographic roughness, resulting in a gentle slope to the south. The rapid lacustrine transgression from southeast to north in the late TST stage of SQ2 formed local beach-bars at shallow depths. During the RST stage of SQ2, a climate transition occurred from arid to humid, resulting in depositional systems that evolved from braided to meandering river deltas. The sedimentary fillings of the SQ1 and SQ2 stages were mainly controlled by tectonic-geomorphology and climate change, respectively. Collectively, our results suggest that the tectonic-geomorphological evolution and climate change jointly controlled the sediment sources and determined the depositional features in the basin.

Age, provenance and tectonic setting of the Tonian–Cryogenian clastic successions in the northwest Bikou terrane, NW Yangtze Block, Central China

Studies on the widely-exposed Neoproterozoic geological records in the Bikou terrane (northwestern Yangtze Block, Central China) have produced different tectonic models (e.g., arc, rift and ridge settings), confusing the relationships between the Bikou and Yangtze blocks in the Neoproterozoic. In addition to the Neoproterozoic Bikou Group igneous rocks and Hengdan Group sedimentary strata which have been well investigated, clastic sedimentary records in the westernmost regions are also crucial for understanding the Neoproterozoic tectonic evolution of the terrane. Here, we target a 3000 m-thick siliciclastic outcrop section along the Bailongjiang River and conduct sedimentological, petrographic, elemental geochemical and zircon U-Pb geochronological analyses to constrain depositional time, sediment provenance and tectonic settings. The outcrop indicates an overall coarsening-upward sedimentary succession, from deep-water sequences to ice-water sequences with dropstone textures. Two volcanic tuffaceous rocks from the basal and middle parts of the succession were dated as 773.2 ± 5.9 Ma and 758.0 ± 8.7 Ma, respectively. The upper parts are characterized by thick, continuous, poorly-sorted glacial diamictites and are conformably overlain by Ediacaran strata. We contend that these diamictites are most likely equivalents to the widespread Cryogenian strata in the Yangtze Block. While provenance analysis results demonstrate felsic bedrock-dominated source terranes with minor mafic contributions, the dropstone gravel components, sandstone petrography and heavy mineral compositions and fine-grained sedimentary rock element concentrations are evidently variable vertically, revealing temporal variations in sediment source-to-sink systems in this region during the late Tonian–Cryogenian. We suggest that the late Tonian deposits were most likely fed by proximal mixed sources with continental arc-related and recycled orogenic terranes, whereas the Cryogenian deposits were dominated by detritus from recycled orogenic terranes. Climate change during the Neoproterozoic glacial-interglacial cycles also played a crucial role in the variable deposit compositions by regulating sediment transport agents and abilities. We favor that the Bikou terrane connected with the Yangtze Block under convergent settings during the early-middle Neoproterozoic and was subsequently under extensional settings. Such findings are a significant step in our understanding of the role of the Yangtze Block in global Neoproterozoic tectonic and climatic frameworks.

Silt-size sediment provenance of the Jianggang radial sand ridges in the southwestern Yellow Sea identified by geochemistry of quartz and K-feldspar

In this paper, the geochemistry of K-feldspar and quartz, combined with MixSIAR and MDS models, was applied to illustrate the provenance of silt-size sediments in the Jianggang RSRs of the Yellow Sea, which profoundly affect the circulation of organic matter. The geochemical distributions revealed an apparent shoreward migration for sediments in the western offshore compared to eastern offshore. The models showed that the onshore RSRs silt-size sediments were mainly from the Yangtze River Mouth and Old Yellow River Delta, with contributions of 43.5 ± 15.3 % and 48.4 ± 13.9 %, respectively. While the offshore RSRs sediments were primarily from the Yangtze River Mouth (61.9 ± 18.0 %). Meanwhile, the transport patterns of silt-size sediments were proposed for the first time. The load calculation further showed that the expansion rate of local coast in 2023–2043 will be lower than in 1997–2017. Therefore, it was recommended to take actions for coastal development.

Decoding the control of active tectonics on the sedimentary budget of a Himalayan River basin: Insights from Sr and Nd isotopic compositions (87Sr/86Sr, εNd) of bed sediments

The interaction between climate and tectonics chiefly governs the erosion and sedimentary budget in the tectonically active Himalayan Mountain chain. In the present study, the relative contribution from the various litho-tectonic units of the Himalaya to the sedimentary budget of the Teesta River System (TRS) (a major tributary of the Brahmaputra system) has been deciphered using the Sr and Nd isotopic compositions (87Sr/86Sr, εNd) of bed sediments. The possible controlling factors for such observed sedimentary provenance have also been assessed. The discharge-weighted sediment transport amount has been translated into the quantification of the erosion rate in the basin. The 87Sr/86Sr and εNd values in the silicate fraction of bed sediments range from 0.74867 to 0.90529 and − 24.3 to −13.9, respectively. In the Teesta main channel, 87Sr/86Sr and εNd show large variability ranging from 0.74867 to 0.82288 and −21.8 to −13.9, respectively along its entire course. This large variability indicates changes in sediment sources i.e., Higher Himalaya and Lesser Himalaya. These data sets show that >60 % of TRS sediments are derived from the Lesser Himalaya, indicating a higher physical erosion over the catchments in the Lesser Himalaya. Our assessment suggests that the sedimentary budget of the Teesta Basin is chiefly governed by higher exhumation as well as the vertical uplift rate of the lesser Himalaya sector of the study area (due to the presence of Rangeet duplex) coupled with focused precipitations. Based on the sediment discharge method, we estimate the erosion rate in the Teesta basin to be 1.7 ± 0.5 mm/yr, which yields a total annual sediment flux of ~41.4 ± 12.4 Mtons. This estimate is comparable to other Himalayan River basins like the Ganga basin, however, lower than the erosion hotspots such as the Brahmaputra basin (Namche Barwa and eastern Syntaxis region) and Indus basin (western Syntaxis region). The obtained erosion rate of the Teesta basin seems to result from the active tectonics in the Sikkim sector of the Himalaya.

In-situ δ18O and 87Sr/86Sr proxies in an unconformable clastic unit at the Ordovician–Silurian transition

Clastic successions found in the carbonate platform of continental margin during the Ordovician–Silurian Transition (OST) period are archives for interpreting paleo-depositional systems. Here, we report in-situ δ18Oquartz and 87Sr/86Srcarbonate isotope chemo-stratigraphy for an unconformable clastic unit from the Cathaysia terrane that rifted off the Gondwana Supercontinent in the Early Paleozoic Era. Our results suggest a depositional proxy and model for geological events attributed to rapid changes in the sedimentary environment during the OST period. Importantly, these results present crucial clues that infer the influence of Paleo-Tethys Sea opening, global eustatic regression, and rapid sedimentary provenance change. Our study provides insight into paleo-tracer that could be a key method for interpreting depositional system of carbonate platform based on in-situ mineral isotope chemo-stratigraphy that preserves the original value of provenance and geochemical condition.

Cretaceous mountain building processes triggered the aridification and drainage evolution in east Asia

Knowledge of the late Mesozoic topography and drainage system of the Tibetan Plateau is essential for understanding the Cenozoic tectonic dynamics of the plateau. However, systematic analyses of the pre-Cenozoic surface uplift history and sediment-routing systems of the Tibetan Plateau remain sparse. Here we present new results for paleocurrents and U-Pb detrital zircon geochronology from the Lanping Basin, a key junction in the southeastern (SE) Tibetan Plateau, and integrate multidisciplinary data sets to constrain sediment provenance and reconstruct paleotopography and its drainage system throughout the Cretaceous. Our results indicate that mid- to Late Cretaceous (ca. Albian−Santonian) tectonically induced surface uplift occurred in the SE Tibetan Plateau, leading to the build-up of an extensive topographic barrier, and resultant rain shadows in the interior of east Asia. Superimposition of this topographic pattern by uplands in the eastern margin of Asia meant that the Cretaceous topography of east Asia was characterized by an enclosed paleo-relief pattern that was high in both the east and west, with drainage from the east and west to the south, contrasting with previously proposed configurations. This topographic pattern interrupted the atmospheric circulation pattern and generated widespread intracontinental desertification and drainage network evolution in east Asia. Our study constrains a key part of the late Mesozoic growth of the Tibetan Plateau prior to the Cenozoic collision between India and Eurasia and will improve our understanding of the paleoclimate, atmospheric circulation, and modern drainage system evolution of the east Asian continent.

Late Oligocene–Early Miocene incision of the Three Gorges and the initial establishment of an east-flowing Yangtze River

The evolutionary history of the Yangtze River plays a key role for understanding the Cenozoic landscape evolution of East Asia. The Three Gorges currently separate the Sichuan Basin from the Jianghan Basin to the east, and their formation is considered to establish an initial connection between the Upper and Middle reaches of the modern Yangtze River. However, despite their importance in the Yangtze River evolution, the age of the initial incision of the Three Gorges remains an ongoing debate. In this study, we use apatite-fission track and (UTh)/He data to model the thermal history of the crust during the gorge formation. Based on the modeled time–temperature paths of samples on vertical profiles and the 3D thermos-kinematic modeling of the gorge region, we suggest that the gorges were initially carved during the Late Oligocene–Early Miocene. This event connected the drainages to the west and east of the gorge regions, leading to the formation of the modern east-flowing Yangtze River. This is also consistent with the sediment provenance of the Yangtze Gravels in the Lower Yangtze reported in previous studies. The gorge formation could be a response to the base level drop in the Jianghan and Subei Basins, which led to an upstream propagation of high erosion rates in the Three Gorges areas.

Sedimentary provenance constraints on the Cretaceous to Cenozoic palaeogeography of the western margin of the Jianghan Basin, South China

Provenance analysis of sedimentary basins is a direct way to understand the uplift of orogenic belts, basin deposition, and evolution of large rivers. A series of Mesozoic and Cenozoic strata from the western Jianghan Basin provides key sedimentary archives for investigating the growth of the surrounding orogenic belts and the evolution of the Yangtze drainage. However, the provenance of these sediments remains unclear. In this study, we report U–Pb data for 1098 detrital zircons from the western Jianghan Basin. We combine these data with published zircon U–Pb ages of potential source areas, paleocurrent data, and paleomagnetic age constraints to reconstruct provenance areas and establish related mountain-building processes. All Cretaceous and Early Cenozoic samples show five major age peaks at 131–210, 432–461, 720–986, 1836–1908, and 2470–2552 Ma. We infer that these sediments are primarily derived from recycled sediments associated with the uplift of the western Jiangnan Orogen. The tectonic uplift of the Jiangnan orogenic belt in the Cretaceous and Early Cenozoic was mainly controlled by the subduction of the Pacific and Indian plates underneath Eurasia. The detritus in the current upper reaches of the Yangtze River did not enter the Jianghan Basin before the Late Eocene (34 Ma). Early Pleistocene strata (1.2–0.7 Ma) show a distinct Cenozoic zircon U–Pb (41 Ma) peak age, which is mainly derived from the detrital sediments of the upper reaches of the Yangtze River. The combination of these data with published provenance tracing results for boreholes in the Jianghan Basin and Yangtze River Delta indicates that the Yangtze River was completely connected between 34 and 1.2 Ma. Such a long time interval may correspond to the tectonic uplift of the Tibetan Plateau and environmental changes during the Late Cenozoic.

A database of detrital zircon U–Pb ages and Lu–Hf isotope of sediments in the South China Sea

AbstractSource‐to‐sink analysis examines the effects of source areas and basin (sink) dynamics on the generation, transport, composition, distribution and deposition of sediment in modern and ancient sedimentary systems. Detrital zircon, as one of the most stable detrital minerals, its U–Pb geochronology and geochemistry is pivotal for sedimentary provenance analysis and reconstructing palaeogeography. The South China Sea (SCS), as the largest marginal sea in the Southeast Asia, is closely related to the uplift of the Tibetan Plateau and the evolution of Chinese rivers. In this study, we mainly collect published detrital zircon of Cenozoic sediments in the SCS (include Hainan and Taiwan Islands). These detrital zircon were concentrated on Cenozoic multiple episodic rift basins in the northern part of the SCS. A total of 21,760 detrital zircon U–Pb data from 293 samples and 995 detrital zircon Lu‐Hf isotope data from 22 samples were collected in this dataset, with the main study epochs being the Palaeogene and Neogene. Best ages of these grains are range from 4,691 to 10 Ma and more than half of them within age less than 500 Ma. The 176Hf/177Hf ratios of the SCS samples ranging from 0.280509 to 0.28306 and the εHf(t) values from −63.8 to 24.6. The main age group of the SCS Cenozoic sediments were at 130–95 Ma, 175–130 Ma and 265–230 Ma. The detrital zircon U–Pb age and Lu–Hf isotope data contained in this dataset is an important geological record of the sedimentary and tectonic evolution of the SCS and the evolution of rivers such as the ancient Pearl River and the ancient Red River, which can provide a basis and important clues or exploring the source of sediments in the SCS, the dynamical processes of basin evolution, the evolution of the coastal drainage system and the tectonic uplift of the Tibetan Plateau.

Developing sediment provenance discrimination tracers using major elements in East China Sea mud deposits

Discriminating shelf sediment provenances using sediment trace metal and rare earth element (REE) concentration and isotope ratios and clay mineral contents has several unavoidable hurdles, such as the effect of sediment grain size on metal concentrations, ubiquitous inclusion of REE-rich heavy minerals in sediments, and meager and inconsistent compositional differences. Furthermore, to date, no study has analyzed and determined a convincing tracer that can differentiate between Huanghe (HH) and Changjiang (CJ) sediment provenances, especially quantitatively. In this study, we quantitatively discriminated the provenances of the southwestern Cheju Island mud deposit (SWCIM) in the northern East China Sea (ECS) shelf, using seven major elements (Si, Al, Fe, K, Na, Ca, and Mg), and further determined the spatial variations of the contributions from the HH and CJ rivers to the northern ECS sediments. The results indicate that the SiO2/Al2O3 and Fe2O3/Al2O3 ratios of the HH, CJ, and Korean (KR) river sediments can be considered as reliable tracers for differentiation of the northern ECS shelf sediment provenance. Furthermore, the quantitative contributions of HH, CJ, and KR to the northern ECS sediment budget were approximately 80, 20, and 0%, respectively. The systematic spatial variations of the HH and CJ river contributions to the sediment provenances in the study area, such as the significant contributions of the HH river in the northwestern part of the SWCIM and the CJ river in the southwestern part, support the availability and applicability of the Fe2O3/Al2O3 ratio as a sediment provenance discrimination tracer. We propose that these major element concentration ratios can be applied to distinguish other siliciclastic shelf sediment provenances.

Multiproxy provenance analyses in the Devonian Villavicencio Formation of the Mendoza Precordillera, Argentina: correlation and geotectonic implications for the SW Gondwana margin

Abstract This work focuses on the sedimentary provenance of the Villavicencio Formation of the Mendoza Precordillera and integrates the information obtained with previous work on other coeval units of the Precordillera Central of San Juan province (Gualilán Group: Talacasto and Punta Negra formations) in western Argentina. Multiproxy provenance analyses are carried out from different applied methodologies (petrography, geochemistry, morphological, and cathodoluminescence studies of detrital zircon grains, and analysis of U-Pb and Lu-Hf isotopes). The Villavicencio Formation is mostly composed of pelites and very fine-grained psammites. The major components are quartz, both monocrystalline and polycrystalline, and metamorphic lithics that associate this unit with a recycled orogen. Regarding geochemistry, the Chemical Index of Alteration (CIA) values are similar to the Post-Archean Australian Shales (PAAS), indicating a null to incipient degree of weathering. The ratios between different trace elements and rare earth elements (REEs) suggest the felsic composition of the source area. Th/U ratios differ, but a secondary uranium enrichment is inferred. The morphological analysis of the zircon grains reveals their mainly plutonic origin. The integration of U-Pb data with Lu-Hf data shows a juvenile-mantle origin in which the populations are dominantly Mesoproterozoic and ɛHf of positive values (up to 12), indicating poor differentiation. The Villavicencio Formation would be the product of deltaic deposits in which its components are dominantly from the Western Pampean Sierras associated with the Grenville orogen, assuming exhumation and erosion of the Mesoproterozoic basement. The data support the hypothesis of equivalence and correlation with the Punta Negra Formation in the Devonian depocenters of the south-central region of the San Juan Precordillera.

Paleozoic tectonic evolution of the proto-Korean Peninsula along the East Asian continental margin from detrital zircon U-Pb geochronology and Hf isotope geochemistry

Detrital zircon geochronology and Hf isotope analysis can be used for inferring provenance characteristics, and to evaluate the tectonic evolution of sedimentary basins and their link with regional orogenesis. The Paleozoic sequences of the Okcheon Belt consist of the Lower Paleozoic Joseon and the Upper Paleozoic Pyeongan supergroups with Middle Paleozoic hiatus locally on top of the Neoproterozoic bimodal volcanic rocks, reflecting an intracontinental rift setting between the two basements (viz. Gyeonggi and Yeongnam massifs) at southern part of the Korean Peninsula. Our detrital zircon U-Pb ages and Lu-Hf isotope results show that all these Paleozoic strata commonly have Paleoproterozoic and Paleozoic zircon ages with rare Meso- to Neoproterozoic ages. The individual zircon populations display following features, allowing estimation of their sedimentary provenances: (i) The Paleoproterozoic zircons (ca. 1.85 Ga and 2.50 Ga) with similar ranges of εHf(t) values are most common in the basement rocks of the Korean Peninsula, and were sourced from both the Gyeonggi and Yeongnam massifs. (ii) The Meso- to Neoproterozoic zircons, preserved only in the Middle to Late Cambrian clastic sedimentary rocks within the carbonate sequences probably reflect proximal provenance. (iii) The youngest Paleozoic zircons of each formation, almost coincident with their deposition ages, suggest presence of syndepositional magmatism, indicating proximal magmatic sources during their deposition. (iv) The Cambrian–Ordovician zircons, from the Lower Paleozoic sequences, but rare in the successive Upper Paleozoic sequences, suggest a provenance change after the hiatus between the two sedimentary successions. (v) The Permian zircons showing different εHf(t) values indicate that detrital sources were varied at that time. The integrated results in our study suggest provenance variability linked to diverse tectonic environments, reflecting prolonged subduction-related crustal evolution of the proto-Korean Peninsula during the Paleozoic.