Detrital Zircon Data Research Articles

Evolution of the northeastern margin of the Kazakhstan paleocontinent: results of petro-geochemical study of sedimentary and volcanogenic-sedimentary rocks of the Zharma-Saur island arc zone

We carried out studies of petrography, petrochemistry, geochemistry and Nd-isotopy of sedimentary and volcanic rocks, as well as U‒Pb dating of detrital zircons from sandstones and tuff sandstones of four stratigraphic units of the Zharma-Saur island arc zone, located in the Middle-Late Paleozoic near the north eastern (in modern coordinates) edge of the Kazakhstan paleocontinent. The data obtained, geological structure and analysis of discriminant diagrams indicate that the formation of sandstones of the Givetian‒Frasnian sequence was the result of erosion and destruction of the Early Paleozoic igneous complexes of the Chingiz-Tarbagatai zone of the Kazakhstan paleocontinent. Tuff sandstones of the Koyanda formation of the Tournaisian stage and the Tersairyk formation of the Visean stage, distributed within the Vorontsov-Saur subzone, are mainly a product of rock destruction and volcanic activity of the Zharma-Saur volcanic arc. The feeding provinces for the sedimentary rocks of the Kokon formation of the Visean stage, which occupies most of the Zharma-Sarsazan subzone, were simultaneously the Caledonides of the Chingiz-Tarbagatai zone and the Early Carboniferous volcanogenic complexes of the Zharma-Saur volcanic arc. Our data show that the Zharma-Saur arc developed near the northeastern margin of the Kazakhstan paleocontinent at the end of the Late Devonian‒in the Early Carboniferous period.

Quantifying Pleistocene loess provenance in midcontinental North America using a mixing model: Implications for glacial lobe evolution along the southern Laurentide ice sheet

Quaternary glaciations have significantly impacted the midcontinental North American landscape, leaving behind a proglacial sediment record of glacial lake deposits, glacio-fluvial sand and gravel, and windblown loess. This paper aims to expand upon a previous study using detrital zircon provenance analysis to investigate midcontinental North American loess provenance in relation to the glacial history of the southern Laurentide ice sheet during the middle to late Pleistocene. The study incorporates previously published detrital zircon data from last glacial tills (representing the Huron-Erie Lobe, Lake Michigan Lobe, Green Bay Lobe, Superior Lobe, Des Moines Lobe, and James Lobe), middle to late Pleistocene loess from several sites along the Illinois and Mississippi River valleys, and suspended sediment load inputs from the Missouri River and Arkansas River. A statistical mixing model (DzMix version 2.2) was used to estimate the relative proportions of glacial and nonglacial sources to Wisconsin Episode, Illinois Episode, and pre–Illinois Episode age loess. We show that mixing models that include the modern suspended sediment loads of the Missouri and Arkansas Rivers significantly improve (up to 23% increase in cross-correlation value) the source characterization of Wisconsin Episode (last glacial) and Illinois Episode (penultimate glacial) loess deposits within the Mississippi River drainage basin. These river sources are dominant inputs for certain loess sites (as much as 51%), but their relative contributions are not static across time and space, which has implications for temporal and spatial differences in relative sediment source estimates and glacial and fluvial sediment transport evolution. Specifically, differences in relative sediment proportion estimates among Wisconsin, Illinois, and pre–Illinois Episode loess support previous evidence for the persistence of a Quebec-Labrador ice dome source through multiple glacial cycles, even with the inclusion of river sources in updated mixing models. Illinois and pre–Illinois Episode loess in the southern portion of our study area received ~20% detrital zircon input from sources similar to the present-day Missouri and Arkansas Rivers, suggesting that these river systems were contributing a significant amount of detritus to the lower Mississippi River valley region during the middle Pleistocene.

Provenance of the Mesoproterozoic Shennongjia Group in the north Yangtze Block, South China, and implications for reconstructions of the Nuna and Rodinia supercontinents

Magmatic activity in the range ca. 1.6−1.5 Ga is spatially restricted globally, and its distribution has been an important tool for constraining the reconstruction of the Nuna supercontinent. Abundant ca. 1.6 Ga detrital zircons have recently been discovered in the Luanshigou and Taizi formations of the middle Mesoproterozoic Shennongjia Group in the north Yangtze Block, South China. Detrital zircon age spectra and multi-dimensional scaling results indicate the Shennongjia Group was derived from variable sources. The ca. 1.6 Ga detrital zircons in the middle Mesoproterozoic units were probably sourced from Laurentia and Australia-Mawson, whereas detrital zircons of other age groups were provided by the local rock units in the north Yangtze Block. Similarities in sedimentary sequences, detrital zircon age spectra, and corresponding Hf isotopic patterns of the Shennongjia Group with other Mesoproterozoic successions in Yangtze Block (e.g., Baoban-Shilu, Huili, and Kunyang groups) suggest that the block contained a number of micro-blocks during the Mesoproterozoic. Furthermore, the compiled new and published detrital zircon data from the north Yangtze Block along with those from other continents containing ca. 1.6 Ga zircons reveal that the Yangtze Block was most likely situated within a rift zone between southeast Australia-Mawson and southwest Laurentia. The ca. 1.6 Ga zircons in the Shennongjia Group were derived from these bounding source regions during the middle Mesoproterozoic. By the late Mesoproterozoic, based on a comprehensive provenance analyses and comparison of detrital zircon data, the Yangtze Block was probably located on the margins of the Rodinia supercontinent, close to north-central India, Australia, and East Antarctica.

Detrital zircon tales between the Rodinia and Pangea supercontinents – Exploring connections between Avalonia, Cadomia and Central Asia

The Rodinia to Pangea supercontinent cycle represents the most recent complete cycle in the geological record and thus informs models on the processes involved in supercontinent dispersal and assembly. The terranes and/or micro-continents of the Avalonian, Cadomian and Central Asian Orogenic Belts are witnesses to this complete cycle but their relationships to Rodinia, each other, and an intermediate stage in this supercontinent cycle represented by the formation of a large (but not supercontinent) landmass, Gondwana, are at time ambiguous. One method for testing these relationships is detrital zircon geochronology; zircons are a highly resistant and easily dateable mineral and thanks to rapid instrumental advances a huge number of detrital zircon datasets are now available. These data can provide a fingerprint whereby suspect terranes and micro-continental fragments can be linked to each other and their parental continent. Nonetheless, in order to develop coherent and testable geological hypotheses from these data it is necessary to integrate the data into a consistent framework. The presented work explores the possibilities and limitations of using detrital zircon data to better understand the position of the Avalonian, Cadomian, and Central Asian terranes in Rodinia and their journey from there to Pangea.

Discerning sediment provenance in the Outer Banks (USA) through detrital zircon geochronology

Detrital zircon data from modern barrier island and estuarine environments in the Outer Banks (Atlantic Coast, USA) were statistically compared to sands from nearby rivers to assist in determining source-to-sink pathways. Fluvial samples, collected from near the Fall Line contact between the Appalachian Orogen and sediments of the coastal plain, all have age unique distributions, making them ideal for tracing provenance. Three samples from the Atlantic foreshore showed high similarities to one another, as well as to three samples from the estuarine (back-barrier) Pamlico and Albemarle Sounds. Mixture modeling with multiple data reduction methods and three different statistical tests for similarity consistently indicated that the nearby Potomac River was the primary source for all Atlantic foreshore and estuarine zircons, followed by minor contributions from the James River in some models. The models indicate little or no sediment contribution from the Susquehanna, Roanoke, Tar, Neuse, Cape Fear, and Peedee Rivers. Both Atlantic foreshore and estuarine sands are therefore interpreted to have initially originated from Appalachian bedrock to the north of their present-day location, and subsequently to have been transported southward through the Chesapeake Bay watershed before deposition in Virginia and North Carolina. Prior to barrier island formation in the last several thousand years, differing geomorphology of the Chesapeake Bay facilitated southward movement of sediments from its constituent rivers via longshore drift, where they were deposited in coastal settings on the mainland. The modern barrier islands, formed during the most recent post-glacial transgression, may be reworked from these deposits, but may also include a contribution from sediments that were derived more recently from relict deposits on the shelf. Oceanographic and sedimentological evidence suggests that movement of sand-sized grains from southern rivers across the back-barrier sounds is unlikely. These findings can assist with coastal resilience planning and resource management in a region under severe threat from climate change and rising sea levels.

Tectonostratigraphic framework and provenance of a Mesoproterozoic rift succession: An example from the Espinhaço Supergroup, SE Brazil

During the Mesoproterozoic era, the amalgamation of the Rodinia supercontinent witnessed numerous intraplate rifting events far-field induced by “Grenvillian-type age” orogenic systems. The intimate connection between tectonics and sedimentation enables the reconstruction of these intraplate rifting cycles, linking them to accretionary events along craton margins. This is essential for understanding the paleotectonic history of continents during the Mesoproterozoic era. In southeastern Brazil, the Espinhaço Supergroup documents long-lasting superimposed rifting events that extended to the eastern border of the São Francisco paleocontinent from the Paleoproterozoic to the Mesoproterozoic era. Three unconformity-bound rift sequences (∼1.77–1.7 Ga; ∼1.57–1.5 Ga; and ∼ 1.19 Ga) have been identified within the Espinhaço Supergroup, terminated by sag-marine deposits of the Conselheiro Mata Group. In the southern extension of the southern Espinhaço range (Cipó range), a detailed sedimentological and stratigraphic study was conducted on a rift-related sequence with unknown stratigraphic positioning. This sequence is bounded at the base by eolian sediments of the Galho do Miguel Formation of the Southern Espinhaço Supergroup and at the top by Ediacaran-Cambrian carbonates and pelites of the Bambuí Group. Examination of the tectonically-induced depositional controls in the provenance signatures involved stratigraphic surveys coupled with U-Pb geochronological data of detrital zircons. The lower section of the rift-related sequence transitions eastward into marine sediments of the Conselheiro Mata Group within the Santa Rita Formation, now identified as the Lower Member. With a maximum depositional age of 1660 ± 32 Ma, this section directly overlies the Galho do Miguel Formation by an erosive unconformity, comprising syn-rift coarse-grained deposits from alluvial and fluvial systems within an inverted half-graben structure. The Lower Member of the Santa Rita Formation provides evidence of the Mesoproterozoic rifting event associated with the Conselheiro Mata Group. The marine sediments of the Undefined sequence have a maximum depositional age of 1462 ± 19 Ma, overlying the Lower Member of the Santa Rita Formation with an erosive unconformity. The stratigraphic position of this sequence remains speculative, possibly linked to a later extensional phase of the Mesoproterozoic Conselheiro Mata rifting event or one of the two continental rifting stages leading to the Neoproterozoic Macaúbas Group.

Mineral chemistry and geothermobarometry of metasedimentary rocks of Central Menderes Massif, Western Türkiye: Metamorphic evolution and source of metapelitic rocks

The Menderes Massif (MM) is the largest metamorphic massif of Türkiye. This study was carried out to determine the origins, metamorphic conditions and age of garnet-mica schists covering large areas in the Central Menderes Massif (CMM). Detrital zircon dating of a garnet-mica schist derived from a quartzofeldspathic source measured the youngest zircon age to be 450 ± 61 Ma (102 % concordant, Th/U = 0.02) Ma and the oldest zircon age to be 1529 ± 18 Ma (97 % concordant, Th/U = 0.02) Ma. The ƐHf(t) values of the selected zircon grains vary between −27.42 and −3.43, and the 176Lu/177Hf isotope values vary between 0.2820 and 0.2827, and these values are consistent with the values obtained from the orthogneisses and paragneisses of the massif. The presence of five Ordovician zircon grains in garnet-mica schists and the intrusive contact with Triassic granites indicate that the source rock of the schists may have been deposited in the Late Ordovician - Triassic interval. Mineral chemical analyses show that garnets are almandine, biotites are Fe-biotite and white micas are muscovite-phengite in composition, and they are affected by metamorphism (greenschist - lower amphibolite facies) under ∼5 kbar pressure and ∼600 °C temperature conditions. For the first time, rutile UPb dating shows that garnet-mica schists underwent metamorphism 43.1 ± 6.1 Ma ago. PT conditions and metamorphic ages obtained from garnet-mica schists show that the overlying units underwent metamorphism in the greenschist-lower amphibolite facies in the Lutetian (Eocene) period.

Dating drainage reversal using mineral provenance along the Yangsan Fault, South Korea.

Tectonics is broadly accepted as one of the main factors controlling long-term landscape evolution. The impact of tectonics on short timescales is most often observed through earthquake rupturings that produce localized, metric-scale deformations. Although these deformations significantly affect the landscape, it remains challenging to precisely correlate major landscape changes with these localized earthquake deformations. Therefore, linking instantaneous deformation to long-term morphological changes often involves a thought experiment with potentially limited temporal resolution. At a paleoseismological site along the slow-moving strike-slip Yangsan Fault in South Korea, we employed optically stimulated luminescence (OSL) dating and detrital zircon analysis on all exposed unconsolidated layers in trench walls. The results reveal a significant provenance shift in the sediments accumulating in the trench, indicating a major reorganization of the drainage network. Based on our OSL and detrital zircon data, we estimate that this change occurred around 70ka. We propose that this drastic drainage reorganization was caused by a combination of very slow, yet continuous, earthquake activity and a temporary reduction in river erosion during the onset of the cold, dry spell characteristic of the MIS4 stage across the Korean Peninsula.

Mesozoic clastic provenance during post-rift evolution of the Essaouira Agadir Basin, Northern Morocco

This study combines several provenance tools, analysis of published structural and geodynamic data, integrated with Low-Temperature Thermochronology (LTT) and time-Temperature Modelling (tTM) to reconstruct the evolution of source-to-sink systems feeding the Essaouira-Agadir Basin (EAB) during the Jurassic (Toarcian, Bathonian, and Kimmeridgian) and Lower Cretaceous (Hauterivian and Barremian).LTT and tTM define timing and rate of subsidence and exhumation of the hinterland and allows modelling of the predicted age and lithology of eroding rock units from the most-likely source locations through time. Extrapolation of predicted surface geology allows recognition of the lithology of sedimentary overburden in the hinterland, much of which has been subsequently eroded and is not preserved in the modern surfical geological record.Heavy mineral, petrography and detrital zircon data analysis was carried out on fluvial and shallow marine sandstones sampled from Jurassic and Cretaceous sections across in the EAB. The results document changing sediment source terrains through time. In the Early and Middle Jurassic, the heavy mineral and detrital zircon signature correlates with a Palaeozoic source, suggesting provenance was dominantly from erosion of Cambrian and Ordovician sandstone in the Central and Western Anti-Atlas. From the Late Jurassic to Early Cretaceous, the heavy mineral and zircon signatures have a strong affinity with Triassic sediments. This indicates a provenance switch to the exhuming West Moroccan Arch (MAM and Western Meseta), interpreted to have been largely covered by Triassic continental red beds at the time.The results help in predicting sediment delivery offshore, into the deep-water basin, where sandstones are a target for hydrocarbon exploration. Defining timing of input, location and composition helps to de-risk exploration. All the intervals examined contained discrete fluvial systems entering in the EAB, suggesting multiple periods of clastic delivery. Results suggest the Middle Jurassic and Hauterivian and Barremian intervals offer the optimum time for delivery of coarse clastics to the shelf margin, and potentially into the deep basin. The source to sink maps developed in this study further characterize these systems, their provenance and timing.

Sedimentary provenance and U-PB detrital zircon in the mesozoic record of the Parecis Basin, Rôndonia and Juruena sub-basin

Sediment provenance analysis is a tool increasingly used in the study of basins. This technique allows identifying the mineralogical and lithological composition of source areas, inferring paleogeography, climate and relief, determining the main sand distribution routes, and estimating the distance and transport time. The Mesozoic volcanic-sedimentary packages of the Parecis Basin mark a significant part of the South American Platform evolution, regarding tectonism, subsidence, sedimentation, basic and alkaline magmatism, uplift and erosion. Also, these packages registers the initial stages of Andean Orogeny subduction. Different authors have established opposite stratigraphic proposals for Parecis Basin regional correlations, and also for its tectonics evolution. Given this context, there are controversies regarding the chronostratigraphic positioning and relationships between the intervals, especially the units called Salto das Nuvens and Utiariti formations. This article presents the faciological framework and facies association, heavy mineral assemblage, ZTR index and sediment sources, and U-Pb detrital zircon ages to both sub-basins. Detrital Zircon data reveal minimum ages of 124 Ma for the Rondônia sub-basin and 245 Ma for the Juruena sub-basin for sedimentary deposition attributed to the base of the Cretaceous units. The detrital age of zircons points to a varied contribution, between elements from different provinces and ages of the Amazon Craton, the Paraguay Fold Belt and records of alkaline magmatism of ages Permo-Triassic and Cretaceous in the different kimberlithic fields of Rondônia and Mato Grosso.

Detrital zircon in Pleistocene aeolianite of the Isipingo Formation at Cape Vidal, KwaZulu-Natal, South Africa, gives age and Hf isotope signatures without provenance significance

Abstract Pleistocene (50 to 70 ka) aeolianite of the Isipingo Formation (Maputaland Group) at Cape Vidal, northern KwaZulu-Natal province, South Africa, contains a combination of three detrital zircon age fractions (A: 940 to 1150 Ma, B: 470 to 720 Ma, C: 230 to 280 Ma) that are also known from Holocene sediments in eastern South Africa, Mesozoic – Cenozoic sandstones in southern Mozambique and from the Carboniferous to Jurassic Karoo Supergroup. Archaean and Palaeoproterozoic bedrock of the Kaapvaal Craton, which is exposed in the drainage basins of rivers that have provided detritus to coastal sedimentary basins, is represented by one single Archaean zircon. Combined laser Raman micro-spectroscopy and estimates of accumulated alpha radiation dose from U and Th concentrations indicate that the virtual absence of zircon older than late Mesoproterozoic cannot be attributed to selective removal of radiation-damaged zircon grains by abrasion during erosion and transport. The Isipingo Formation sandstone at Cape Vidal is a product of sedimentary recycling, potentially involving river transport from the continental hinterland, water- and wind-borne drift parallel to the coast and local recycling. Because of the similarity in detrital zircon distribution patterns of the sandstone and all of its potential Palaeozoic to Cretaceous sedimentary precursors, detrital zircon data cannot provide useful information on the relative importance of these processes, or on the routing of detritus to its final site of deposition.

Sedimentary provenance of the Upper Devonian Old Red Sandstone of southern Ireland: an integrated multi-proxy detrital geochronology study

The Devonian Old Red Sandstone (ORS) magnafacies of southern Ireland is hosted in the Early Devonian Dingle Basin and the Late Devonian Munster Basin. Following the closure of the Iapetus Ocean during the Caledonian Orogeny, the Dingle Basin developed as a pull-apart structure before being deformed by Acadian tectonic activity. The Munster Basin developed as a half-graben structure in response to post-Acadian north–south extension in the region. Thus, the Irish ORS provides insights into the region's tectonic history owing to its temporal and spatial proximity to the Caledonian ( c . 475–425 Ma), Acadian ( c . 400–390 Ma) and Variscan orogenic events ( c . 390–290 Ma). This study presents the first detrital zircon and apatite U–Pb geochronological data for the Upper ORS (UORS) in southern Ireland in addition to detrital white mica 40 Ar/ 39 Ar geochronological data to help unravel the depositional history of the Irish UORS and to assess the possible role of sedimentary recycling in Late Devonian basin development. Most UORS samples contain few late Neoproterozoic detrital zircon grains and are instead dominated by early Paleozoic and c. 1.1 Ga zircons. These populations represent recycling of northerly-derived Ordovician to Silurian strata of the Southern Uplands–Longford–Down terrane, which are of Laurentian affinity, and not recycling of Lower ORS (which contains a significant number of late Neoproterozoic detrital zircons) as previously thought. Similar detrital zircon dates have been observed in Givetian–Frasnian quartzites of the Pulo do Lobo Zone on the Iberian Peninsula, providing a possible Rheic Ocean link with the UORS.

Ichnological records associated with dermestid beetles in dinosaur bones from Lala's Place (Maastrichtian), Ramos Arizpe, Coahuila, Mexico, and their taphonomic implications

We analyzed the ichnological record of hadrosaur remains from the dinosaur quarry CLP-3, Lala's Place, Ramos Arizpe, Coahuila, where taphonomic research is ongoing. These fossils have been determined to stratigraphically belong to the Cerro del Pueblo Formation, deposited in a deltaic floodplain environment. The Lala's Place quarries have been determined to belong to the early Maastrichtian (69 ± 5 Ma) through U/Pb detrital zircon dating. Thirteen trace fossil morphotypes were identified in six bone elements, interpreted to belong to a single individual. These traces were identified to belong to the ichnospecies Cuniculichnus seilacheri, cf. Cubiculum cooperi, Cubiculum atsintli. A new ichnospecies, Cubiculum subcorticalis n. isp., characterized by a composite feeding-pupation trace with subcortical chambers, is also described. Based on these findings, temporal range of the previously described ichnospecies is expanded to the Maastrichtian stage in the Cerro del Pueblo Formation. Previous work has reported these ichnospecies and associated them with dermestid beetles; this work also associates these traces with dermestids through morphological analyses and using for the first time the novel Usefulness in Identification and Differentiation (UID) index, recently proposed for this taxon. These traces indicate that the carcass was exposed to a subaerial environment for at least 20–30 days, reaching a dry stage in which dermestid adults fed, reproduced, and oviposited. Larvae produced these traces by excavating chambers to avoid cannibalism by other larvae.

Glacially influenced provenance and Sturtian affinity revealed by detrital zircon U–Pb ages from sandstones in the Port Askaig Formation, Dalradian Supergroup

The Cryogenian ‘Sturtian’ snowball Earth glaciation ( c. 717–658 Ma) likely had a major role in shaping continental landscapes and biotic radiations of the late Neoproterozoic Era. However, an incomplete sedimentary record and inadequate syn-glacial age constraints make Cryogenian studies challenging. We present detrital zircon U–Pb ages for >2000 zircons from 11 sandstone samples taken at <200 m stratigraphic resolution throughout the Port Askaig Formation, a c. 1.1 km thick glaciogenic succession within the Dalradian Supergroup of Scotland and Ireland. Eight new maximum depositional age constraints, including a key constraint on deglaciation (<662.7 ± 7.8 Ma), support lithostratigraphic and stable isotope evidence that suggests the Port Askaig Formation preserves a relatively complete record of the global ‘Sturtian’ glaciation. An increasing contribution from Archean and Paleoproterozoic detritus to the sandstones through the lower c. 500 m of the Port Askaig Formation likely reflects the progressive glacial unroofing of the previously buried Lewisian Gneiss terrane. Archean and Paleoproterozoic grains then become scarce in the uppermost c. 300 m of the formation, which we attribute to glacial modification of the Laurentian continental margin landscape during the waning stage of ‘Sturtian’ glaciation. The disruption to sediment transport pathways caused by this modification, and evidenced by the detrital zircon data, points to partially warm-based ‘Sturtian’ ice sheets that were, to some degree, dynamic.

The First Results of U–Th–Pb Isotopic Dating of Detrital Zircons from the Chenka Sandstones – a Contribution to the Stratigraphy of the Cimmerides of the Mountainous Crimea

The First Results of U–Th–Pb Isotopic Dating of Detrital Zircons from the Chenka Sandstones – a Contribution to the Stratigraphy of the Cimmerides of the Mountainous Crimea

Unravelling the evolution of a continental rift by a multi-proxy provenance study (Albertine Rift, Uganda)

Sedimentary provenance analysis has rarely been applied to continental rifts, because source-rock terrains are assumed to be uniform and supply systems stable and closely connected to the formation of graben shoulders. Here, we test the suitability of multi-proxy sedimentary provenance analysis to unravel the evolution of a segment of the East African Rift System from its sedimentary record, where an extreme relief has been created and a continent-wide drainage system has been affected. Multi-proxy techniques include petrographic-mineralogical analysis (framework, heavy mineral spectra, zircon morphology, and colour), as well as single-grain garnet geochemistry, Zr-in-rutile thermometry, and geochronological methods (detrital zircon U–Pb ages). Published data are compiled and complemented by new U–Pb detrital zircon data of rift sediments. Because a comprehensive database of basement source-rock compositions from East Africa is missing, published modern river sand compositions have been added to provide endmember source fingerprints. The selected Albertine Rift is surrounded by four main source terrains within the East African Basement, which cannot be separated clearly by individual provenance indicators. Most useful were heavy mineral spectra, garnet composition, and with limitation Zr-in-rutile thermometry showing different metamorphic overprint. U–Pb detrital zircon spectra assisted well in detecting juvenile magmatism of different orogenic events, but repeated inheritance in younger units prevented a strict allocation. Petrographic maturity turned out to be more dependent on multi-cycle detritus as on climate shift. Applying endmember composition to rift sediments, three evolutionary stages of the Albertine Rift could be identified which coincide with basin-scale unconformities. Moreover, we could prove a large, southwest trending drainage network in East Africa during the Miocene, which was destructed step-wise by ongoing rifting. Extreme uplift of the Rwenzori Mountains up to 5109 m could be documented by a specific set of provenance indicators justified by modern river sand. Three main lessons can be drawn from this study: (1) basement units can be only reliably characterized by a combination of provenance-sensitive parameters, and here, the frequently used U–Pb detrital zircon ages are not sufficient; (2) it is possible to define subunits, e.g., individual fault-blocks within the rift; and (3) chemical weathering is unproblematic when applying a multi-parameter approach even in a tropical setting.Graphical abstract

Channel evolution in the lower reach of palaeo Fen River: evidence from detrital apatite petrochronology and zircon geochronology

This study provides a comprehensive analysis combining multi-element (Sr, Y, Th, U and REE) geochemistry and U–Pb geochronology of single-grain apatite with zircon U–Pb ages from channel sand deposits of the palaeo Fen River, collected at the Chaizhuang and Weijiazhuang sites, corresponding to sediments from the Late Pleistocene and late Middle Pleistocene, respectively. The results unveil that the analysed apatites originated from a varied assemblage of source rocks, encompassing mafic–ultramafic rocks, intermediate to felsic I-type plutons, highly fractionated S-type granites and pegmatites, as well as assorted metamorphic rocks. U–Pb age dating of detrital zircons and apatites identifies three predominant age peaks at 2.4, 2.2 and 1.8 Ga, consistent with known tectonothermal episodes within the North China Craton (NCC). The similarity in U–Pb age spectra for both zircon and apatite, along with comparable apatite geochemical characteristics across both the Chaizhuang and Weijiazhuang sections, indicates stable provenance with little to no change from the late Middle Pleistocene to the Late Pleistocene. This continuity in provenance signatures suggests an absence of shift in drainage patterns or sediment sources, indicating that the current location and pattern of Fen River lower reach drainage was not formed at least by then. Consequently, it is inferred that the detrital material composing the palaeo Fen River sediments during this period predominantly originated from the NCC.

Tracing provenance of phosphorite in the Shifang phosphorite deposit: Insights from the genesis of detrital zircon

Phosphorites (P2O5 content > 18 wt%) are widespread in the world; however, high-quality phosphorite (P2O5 content > 30 wt%) is exceptionally rare. In South China, the Devonian Shifang phosphorite deposit represents not only a high-quality phosphorus ore resource but also hosts abundant rare earth elements (up to 3677.6 ppm). Despite its significance, the provenance of this unique phosphorite deposit has remained unclear. In this study, we conducted U-Pb dating, Hf isotope, and trace element concentrations analysis of detrital zircon from the phosphorite in the Shifang phosphorite deposit to well constrain the specific provenance and potential material source of the phosphorite. Cathodoluminescence (CL) images and trace elements analysis of zircons suggested that the majority of zircons have a magmatic origin. The U-Pb dating age of these zircons revealed three main age peaks at ∼ 560–520 Ma, ∼850–750 Ma and ∼ 1050–950 Ma. A comparison of the εHf values of zircons for the same age group worldwide revealed the following: (1) The 1050 ∼ 950 Ma detrital zircon in the Shifang phosphorite deposit could be derived from North India; (2) The 850–750 Ma zircons originated from Tonian granites in the western South China Block; (3) The 560–520 Ma zircons had two sources, one could be the Kuungan orogeny in the east-Gondwana, and another could be the Arabian-Nubian Shield in the northern-west-Gondwana. In addition, our new age histograms of detrital zircon U-Pb ages are well consistent with underlying strata, such as Silurian and early-middle Devonian. Combining these findings with the geological activities in the study area, we conclude that zircons in the Shifang phosphorite deposit may directly originate from the underlying strata in the study area and the Cambrian Qingping phosphorite deposit may have served as an essential phosphorus source for the Shifang phosphorite deposit.

Reassessing early to mid-Neoproterozoic (∼885–720 Ma) tectonic evolution of the southwestern Jiangnan Orogen: A detrital zircon perspective

The Neoproterozoic Jiangnan Orogen (JNO) marks the consolidation of the South China Block, sparking ongoing debates on its early to mid-Neoproterozoic tectonic evolution. In this study, we have gathered detrital zircon data from the southwestern JNO, presenting new detrital zircon U-Pb ages alongside trace element data from the mid-Neoproterozoic Banxi Group and Sinian System within this region. Our objective is to illuminate the early to mid-Neoproterozoic tectonic evolution within the southwestern JNO through a comprehensive detrital zircon analysis. The obtained dating results derived from detrital zircons reveal maximum depositional ages of ∼733 Ma and ∼713 Ma for Mobin Formation (Banxi Group) and Jiangkou Formation (Sinian System) sedimentary rocks, suggesting a proximal source, possibly originating from magmatic rocks within the southwestern JNO. Within the paleo-geographic context, it is plausible that these samples were deposited within the deep-water expanse of the Nanhua Rift Basin. Trace element analysis of detrital zircons within the southwestern JNO highlights distinctive fluctuations, delineating three crucial time points (∼885 Ma, ∼835 Ma, and ∼810 Ma): the beginning of early Neoproterozoic subduction of the South China Ocean towards the Yangtze Block beneath the southwestern JNO, the subduction slab rollback, and the Nanhua rifting initiation. The discernible shifts in detrital zircon age distributions within these sedimentary rocks serve as robust validation for the proposed model and crustal reworking. We then propose that the southwestern JNO was in a lull of magmatism before ∼885 Ma, then transitioned to a convergent setting around 885–835 Ma, subsequently subduction slab rollback after ∼835 Ma. The time of final assembly of the Yangtze and Cathaysia blocks in the southwestern JNO is no later than ∼810 Ma. This transformative period (∼810–720 Ma) witnessed the development of a rift basin concurrently with the accumulation of deep-water deposits within the southwestern JNO.

Permian tectonic evolution of the proto-Japan and East Asia: Insights from detrital zircon geochronology and crystal morphology

Combination analyses of detrital zircon ages and morphology from Permian sandstones in Japan provide evidence of orogenic evolution caused by collision in East Asia and reveal their paleogeographic setting. This study compares published and newly measured data from Permian fore-arc accretionary complexes (Akiyoshi Belt) and back-arc basin deposits (Maizuru Belt) in the Inner Zone of Southwest Japan. The fore-arc deposits and lower part of the back-arc deposits consist mainly of approximately 300–250 Ma zircon grains that are close to the depositional ages and are generally angular to subangular. These sediments formed around the Late Paleozoic volcanic arc isolated from the older continental crust, and their source rocks were exposed immediately prior to their erosion and transport and were transported directly to the depositional site in a relatively short time. In contrast, upper part of the back-arc deposits generally contains approximately 2,700–1,800 and 500–250 Ma zircon grains, which are commonly older than their depositional ages and are rounded. These grains were supplied from multiple sources, such as the Paleozoic volcanic arc and Precambrian continental block, and were affected by long-distance transport and a strong abrasion effect during transport. Comprehensive detrital zircon data emphasize that the oceanic arc–back-arc basin–continental margin system formed along the eastern margin of East Asia, and that the volcanic arc collided with the eastern margin of the Sino-Korean Block during the Permian. The variation in detrital zircon ages and shapes of back-arc deposits provides a constraint for modeling the East Asian Permian collision. Detritus derived from continental crust was captured by a back-arc basin and blocked by the uplift zone of the volcanic arc. However, a small amount of detritus originating from the continental crust was supplied to the fore-arc.