Detrital Zircon Data Research Articles

Carbonate Massifs of Talas Sections in Tectonic Setting of the Middle Tien Shan

In the Dzhetym Range, there are well-known Precambrian massifs of marbled limestones and quartzites, which have no analogues throughout the Middle Tien Shan. The authors establish that the quartzite-carbonate stratum occupies the highest structural position in the series of nappes of the region. The U–Pb dating of detrital zircon and zircon from intrusions reliably proves the Riphean age of the quartzite-carbonate stratum, which grounds to compare it with the autochthonous complex of the Karatau–Talas terrane. The autochthonous and parautochthonous units of the Dzhetym Range are composed of Riphean–Vendian sediments of the Middle Tien Shan. The geochemical characteristics and the refined age of the Bolshoi Naryn volcanic-plutonic complex, obtained in the course of this study, indicate that in the Late Riphean this area was a segment of the periocean continental rift, manifested in the time interval of 750–700 Ma ago throughout the entire Tarim–Tien Shan–Kazakhstan region.

Evolution of the early Mesozoic Cordilleran arc: The detrital zircon record of back-arc basin deposits, Triassic Buckskin Formation, western Arizona and southeastern California, USA

Abstract A shift in the depositional systems and tectonic regime along the western margin of Laurentia marked the end of the Paleozoic Era. The record of this transition and the inception and tectonic development of the Permo-Triassic Cordilleran magmatic arc is preserved in plutonic rocks in southwestern North America, in successions in the distal back-arc region on the Colorado Plateau, and in the more proximal back-arc region in the rocks of the Buckskin Formation of southeastern California and west-central Arizona (southwestern North America). The Buckskin Formation is correlated to the Lower–Middle Triassic Moenkopi and Upper Triassic Chinle Formations of the Colorado Plateau based on stratigraphic facies and position and new detrital zircon data. Calcareous, fine- to medium-grained and locally gypsiferous quartzites (quartz siltstone) of the lower and quartzite members of the Buckskin Formation were deposited in a marginal-marine environment between ca. 250 and 245 Ma, based on detrital zircon U-Pb data analysis, matching a detrital-zircon maximum depositional age of 250 Ma from the Holbrook Member of the Moenkopi Formation. An unconformity that separates the quartzite and phyllite members is inferred to be the Tr-3 unconformity that is documented across the Colorado Plateau, and marks a transition in depositional environments. Rocks of the phyllite and upper members were deposited in wholly continental depositional environments beginning at ca. 220 Ma. Lenticular bodies of pebble to cobble (meta) conglomerate and medium- to coarse-grained phyllite (subfeldspathic or quartz wacke) in the phyllite member indicate deposition in fluvial systems, whereas the fine- to medium-grained beds of quartzite (quartz arenite) in the upper member indicate deposition in fluvial and shallow-lacustrine environments. The lower and phyllite members show very strong age and Th/U overlap with grains derived from Cordilleran arc plutons. A normalized-distribution plot of Triassic ages across southwestern North America shows peak magmatism at ca. 260–250 Ma and 230–210 Ma, with relatively less activity at ca. 240 Ma, when a land bridge between the arc and the continent was established. Ages and facies of the Buckskin Formation provide insight into the tectono-magmatic evolution of early Mesozoic southwestern North America. During deposition of the lower and quartzite members, the Cordilleran arc was offshore and likely dominantly marine. Sedimentation patterns were most strongly influenced by the Sonoma orogeny in northern Nevada and Utah (USA). The Tr-3 unconformity corresponds to both a lull in magmatism and the “shoaling” of the arc. The phyllite and upper members were deposited in a sedimentary system that was still influenced by a strong contribution of detritus from headwaters far to the southeast, but more locally by a developing arc that had a far stronger effect on sedimentation than the initial phases of magmatism during deposition of the basal members.

Detrital zircon age spectra of middle and upper Eocene outcrop belts, U.S. Gulf Coast region

AbstractRecently reported detrital zircon (DZ) data help to associate the Paleogene strata of the Gulf of Mexico region to various provenance areas. By far, recent work has emphasised upper Paleocene‐lower Eocene and upper Oligocene strata that were deposited during the two episodes of the highest sediment supply in the Paleogene. The data reveal a dynamic drainage history, including (1) initial routing of western Cordilleran drainages towards the Gulf of Mexico in the Paleocene, (2) an eastward shift of the western continental divide, from the Jura‐Cretaceous cordilleran arc to the eastern edge of the Laramide province after the Paleocene and (3) a southward shift, along the eastern Laramide province, of the headwaters of river systems draining to the Mississippi and Houston embayments at some time between the early Eocene and Oligocene. However, DZ characterisation of most (~20 Myr) of the middle Eocene‐lower Oligocene section remains limited. We present 60 DZ age spectra, most of which are from the middle or upper Eocene outcrop belts, with 50–200‐km spacing. We define six to eight distinct groups of DZ age spectra for middle and upper Eocene strata. Data from this and other studies resolve at least six substantial temporal changes in age spectra at various positions along the continental margin. The evolving age spectra constrain the middle and upper Eocene drainage patterns of large parts of interior North America. The most well‐resolved aspects of these drainage patterns include (1) persistent rivers that flowed from erosional landscapes across the Paleozoic Appalachian orogen either into the low‐lying Mississippi embayment or directly into the eastern Gulf; (2) at least during marine regressions, a trunk channel that likely flowed southward along the axial part of Mississippi Embayment and integrated tributaries from the east and west; and (3) rivers that flowed to the Houston embayment in the middle Eocene that likely originated in the Laramide province in central Colorado and southern Wyoming, as Precambrian basement highs in those source areas were being unroofed.

Secular Changes in Fore-arc Sandstones and Their Provenance in Cretaceous Southwest Japan: U–Pb Dating of Detrital Zircons

Secular Changes in Fore-arc Sandstones and Their Provenance in Cretaceous Southwest Japan: U–Pb Dating of Detrital Zircons

Detrital zircon U-Pb ages of the late Mesoproterozoic–Neoproterozoic Qiaotou formation in the Liao-Ji area of the North China Craton: implications for Rodinia reconstruction

ABSTRACT The Qiaotou Formation comprises the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin and Liaoning Provinces at the eastern margin of the North China Craton (NCC). The depositional age of the formation is 1.1–0.9 Ga, as constrained from the ages of the youngest detrital zircons and later mafic intrusions. U-Pb age dating of detrital zircons yielded age peaks at 1.16, 1.58, and 1.74 Ga, and a minor peak of 2.47 Ga. The late Neoarchaean to Palaeoproterozoic detrital zircons were derived from the ca. 2.5 Ga Longgang and Liaonan blocks, ca.1.9 Ga magmatic/metamorphic rocks and late Palaeoproterozoic extensional-related magmatic rocks in NCC. The abundance of Mesoproterozoic zircon grains is less easy to explain. The possible source may represent (i) possibly concealed/vanished Grenvillian magmatic rocks in NCC, or (ii) derivation from the Qinling Microcontinent or (iii) Fennoscandian shield, or (iv) São Francisco–Congo Craton.

A missing link of the Proto-Tethys Ocean between the Qinling and Qilian orogens, China: Insights from geochronology and structural geology

The Qinling-Qilian connection zone (QQCZ) is a key area to reveal the relationship and to make a link of the North Qinling and the North Qilian orogens, China. Here we present U–Pb dating data of detrital zircons from four sedimentary/metasedimentary rocks in the QQCZ and the southwestern North China Block (NCB) and detailed regional structural data. Three episodes of fold deformation (D1, D2 and D3) are distinguished in the QQCZ, with the former two occurred during the early Paleozoic. The D1 deformation is mainly characterized by regionally penetrative schistosity and some residual rootless intrafolial folds due to the intensive superpositions by the subsequent D2 and D3 deformations. The D2 deformation characterized by tight folds, associated axial plane foliations and crenulation lineations indicates a stress field characterized by NNE–SSW-directed compression, which may be induced by the collision between the NCB and the southern blocks. The D3 deformation which might occur during the Mesozoic is marked by upright open folds and kink bands. The similarity of the detrital zircon age spectra of the Huluhe Group in the North Qilian Orogen and the Erlangping Group in the North Qinling Orogen suggests that the two groups have similar provenance, which may indicate that the North Qilian Orogen corresponded to the North Qinling Orogen in a regional tectonic framework. In addition, the remarkable age peak at ~435 ​Ma of the detrital zircon age spectrum of the Duanjiaxia Formation in the southwestern NCB indicates that this formation obtained the provenance of the North Qilian and North Qinling orogens, which may be generated by the collage of the southwestern NCB and the QQCZ during the Late Ordovician–Early Silurian. Based on structural, detrital zircon and metamorphic data, we suggest that the North Qilian and North Qinling orogens underwent similar evolution during the early Paleozoic due to the closure of the North Qilian and the Kuanping oceans which located at the northern boundary of the Proto-Tethys Ocean.

Tectonic Setting of the Eastern Margin of the Sino-Korean Block in the Pennsylvanian: Constraints from Detrital Zircon Ages

To test the previous hypothesis that upper Paleozoic sediments in the eastern Sino-Korean Block were mostly derived from the paleo-orogen located to the east, we compared published and new U–Pb age data of detrital zircons from Pennsylvanian strata distributed in the Sino-Korean Block (SKB). The age distributions of detrital zircons from different localities of Pennsylvanian strata in North China reflect varying contributions from the Inner Mongolia Paleo-uplift in the north and the Central China Orogenic Belt in the south. The supply of detritus from the northern source to distant areas, however, appears to have been limited during the Pennsylvanian times. The age distributions of detrital zircons from Korean Pennsylvanian strata located in the east of the SKB are characterized by a dense cluster of 1.84–1.90 Ga and differ from those of North China. The Korean age characteristic is best explained by strong influences of the detritus derived from the Paleoproterozoic Yeongnam Massif in southeastern Korea. Along with the significant number of zircons that record syn- to near-depositional magmatic activities, this observation supports the hypothesis of the existence of an active continental margin setting in the east of the SKB.

Provenances of the Ediacaran sedimentary rocks in the Zhuguangshan area and their implications for granitoid-related uranium mineralization in South China

The terrigenous clastic sedimentary rocks in the Zhuguangshan uranium ore field of the Cathaysia Block, South China, were selected to reveal their petrogenesis and implications for granitoids-related uranium mineralization in South China. LA-ICP-MS U-Pb dating of detrital zircons shows that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area are characterized by a significant age peak at ca. 1023 Ma and that the Grenville-aged detritus in the Zhuguangshan area originated from northern India and eastern Antarctica. Elemental geochemical features show that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area were derived from a recycled sedimentary source and were deposited in a passive continental margin. The geochemical composition of the source rock is similar to that of intermediate-felsic rocks which are likely composed of andesite-granite. Petrographic and geochemical features unravel that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area underwent mildly-intensive chemical weathering. Through the comparison of the terrigenous clastic rocks between the Cathaysia Block and the southeastern margin of the Yangtze Block, we suggest that the high maturity and high U and Th contents of the terrigenous clastic rocks might be the key factors causing the granite-related uranium mineralization in the Cathaysia Block.

Recognizing drainage reorganization in the stratigraphic record of the Neogene foreland basin of the Central Andes

Changes in drainage basin reorganization as preserved in the stratigraphic record have direct implications for the composition, organization, and scaling relationships of sedimentary systems. However, isolating the stratigraphic signature of drainage basin reorganization in response to tectonic and/or climatic drivers can be challenging. In the Neogene foreland basin of the southern Central Andes between 28°–31°S, the tectonically-controlled reorganization of basin catchment area has been cited as an important control on the basin stratigraphy. To resolve the signature of drainage basin reorganization in the Central Andean foreland, we conducted a basin-scale study integrating detailed sedimentology from four measured sections with multi-method provenance analysis to reconstruct foreland sediment routing pathways between 28°–31°S. Our regional synthesis suggests that the foreland basin has been connected by an axial sediment routing system since the early Miocene. Statistical analysis and graphical comparison using multidimensional scaling of new and published detrital zircon data from 45 samples resolves tectonically controlled changes in the catchment area in the late Miocene, including an eastward shift of the Andean drainage divide. This study provides the first evidence for expansion of the catchment area east of the basin draining the emerging basement-cored highlands of the Sierras Pampeanas. This study demonstrates that, when combined, provenance and detailed sedimentologic data sets provide a powerful tool to recognize and interpret drainage basin reorganization in the stratigraphic record and thus reconstruct the tectono-climatic and paleogeographic evolution of sedimentary systems.

The Neoproterozoic Andrelândia group: Evolution from an intraplate continental margin to an early collisional basin south of the São francisco craton, Brazil

New U–Pb and Lu–Hf zircon data for the Andrelândia Group are presented and discussed with the previously published data to propose an evolutionary model. The Andrelândia Group consists of two depositional sequences that record the geotectonic evolution from Tonian to Ediacaran times. Both sequences are part of the Andrelândia Nappe System, a fold-and-thrust system, generated in the 630-600 Ma interval, during the evolution of the Neoproterozoic convergence in the interference zone between the Southern Brasília and the Ribeira orogens, SE Brazil. The Andrelândia Group rocks record greenschist to granulite facies metamorphism related to this convergence. The lower sequence consists of paragneiss, metapelite, quartzite, metachert, calc-silicate and mafic rocks distributed in five lithofacies associations. They record shallow to deep water sedimentation coeval with mafic magmatism at the southern border of the São Francisco Craton. U–Pb data obtained from detrital zircon grains of deep water quartzites indicate a maximum depositional age of ca. 970 Ma. The U–Pb age peaks can be correlated to major events in the adjacent São Francisco paleocontinent. εHft isotopic signature obtained in this study shows a predominance of juvenile sources for the Mesoproterozoic and crustal reworking and juvenile additions for the Paleoproterozoic. This can be related to source rocks from the Espinhaço Supergroup and from the Mineiro Belt, respectively. We interpret our data together with previous published detrital zircon data and whole-rock εNdt signatures to suggest that the lower sequence of the Andrelândia Group is related to a passive margin of the São Francisco paleocontinent with a platformal and a deep water succession with roughly similar sources, indicating likely a resedimentation process. The upper sequence of the Andrelândia Group consists of a monotonous package of biotite schist interpreted as metamorphosed plagioclase sandstones and siltstones. The upper sequence covers the lower sequence units unconformably. Deposition occurred in a relatively deep and fast subsiding basin during the early collisional stage of the southern Brasília Orogen. Previously published U–Pb, Sm–Nd and Lu–Hf data for the upper sequence constrain likely sources in the southern São Francisco Craton and possibly in the early stages of the Neoproterozoic Socorro-Guaxupé arc, established at the eastern margin of the Paranapanema paleocontinent, which collided with the São Francisco paleocontinent during West Gondwana assembly.

Proterozoic tectonic evolution of the Tarim Craton: New insights from detrital zircon U-Pb and Lu-Hf isotopes of metasediments in the Kuruktag area

The Proterozoic is the longest Eon in geological history and witnessed the assemblies and breakups of the Columbia and Rodinia supercontinents. The Tarim Craton has been proposed to be a building block of these supercontinents. However, its tectonic evolution during late Paleoproterozoic to earliest Neoproterozoic (ca. 1.8–0.8 Ga) has been poorly understood, due to the paucity of geological record. In this paper, we present U-Pb and Lu-Hf isotopic data for detrital zircons from the metasediments of the early Neoproterozoic Paergangtag Group and the Paleoproterozoic Xinditag Group in the Kuruktag area, northern Tarim Craton.Although formed approximately 1 billion years later, the Paergangtag Group contains detrital zircons almost identical to those inthe Xinditag Group. LA-ICP-MS U-Pb dating yields a ca. 2.0 Ga age peak, as well as a group of older zircons of ca. 2.5 Ga in six samples from these two groups. Lu-Hf data show that the ca. 2.0 Ga zircons have variableεHf(t) values (−28.1 to 0.1), indicating the detritus were mostly derived from reworked continental crusts. The older zircons around 2.5 Ga have both negative and positiveεHf(t) values (−28.5 to 9.5), indicating a prolonged and complicated crustal growth and reworking process in the source area. It is inferred that the zircons in these samples were likely derived from southeastern Tarim Craton, where a ca. 2.0 Ga orogenic event has been documented.The fact that the Neoproterozoic Paergangtag Group contains only Paleoproterozoic and older zircons suggests that the Tarim Craton was not involved in the Grenville Orogeny, which developed between the colliding continents in the interior of the Rodinia Supercontinent. In contrast, the Tarim Craton was probably on the periphery of the Rodinia Supercontinent and was involved in the peripheral subduction zone of the supercontinent shortly after the deposition of the Paergangtag Group. Our new data imply that the Tarim Craton might have been a tectonically stable continent for nearly 1 billion years from ca. 1.8 to 0.9 Ga.

Detrital-zircon analyses, provenance, and late Paleozoic sediment dispersal in the context of tectonic evolution of the Ouachita orogen

Abstract New analyses for U-Pb ages and εHft values, along with previously published U-Pb ages, from Mississippian–Permian sandstones in synorogenic clastic wedges of the Ouachita foreland and nearby intracratonic basins support new interpretations of provenance and sediment dispersal along the southern Midcontinent of North America. Recently published U-Pb and Hf data from the Marathon foreland confirm a provenance in the accreted Coahuila terrane, which has distinctive Amazonia/Gondwana characteristics. Data from Pennsylvanian–Permian sandstones in the Fort Worth basin, along the southern arm of the Ouachita thrust belt, are nearly identical to those from the Marathon foreland, strongly indicating the same or a similar provenance. The accreted Sabine terrane, which is documented by geophysical data, is in close proximity to the Coahuila terrane, suggesting the two are parts of an originally larger Gondwanan terrane. The available data suggest that the Sabine terrane is a Gondwanan terrane that was the provenance of the detritus in the Fort Worth basin. Detrital-zircon data from Permian sandstones in the intracratonic Anadarko basin are very similar to those from the Fort Worth basin and Marathon foreland, indicating sediment dispersal from the Coahuila and/or Sabine terranes within the Ouachita orogen cratonward from the immediate forelands onto the southern craton. Similar, previously published data from the Permian basin suggest widespread distribution from the Ouachita orogen. In contrast to the other basins along the Ouachita-Marathon foreland, the Mississippian–Pennsylvanian sandstones in the Arkoma basin contain a more diverse distribution of detrital-zircon ages, indicating mixed dispersal pathways of sediment from multiple provenances. Some of the Arkoma sandstones have U-Pb age distributions like those of the Fort Worth and Marathon forelands. In contrast, other sandstones, especially those with paleocurrent and paleogeographic indicators of southward progradation of depositional systems onto the northern distal shelf of the Arkoma basin, have U-Pb age distributions and εHft values like those of the “Appalachian signature.” The combined data suggest a mixture of detritus from the proximal Sabine terrane/Ouachita orogenic belt with detritus routed through the Appalachian basin via the southern Illinois basin to the distal Arkoma basin. The Arkoma basin evidently marks the southwestern extent of Appalachian-derived detritus along the Ouachita-Marathon foreland and the transition southwestward to overfilled basins that spread detritus onto the southern craton from the Ouachita-Marathon orogen, including accreted Gondwanan terranes.

Upper Triassic Sequences of the Crimean Mountains: First Results of U–Pb Dating of Detrital Zircons

The first results of U–Pb dating of detrital zircons from two samples that characterize the Tauric and Eski-Orda Series of the Cimmerian structural complex of the Crimean Mountains are presented. The strong similarity between the detrital zircons ages from the Lower Tauric Formation of the Tauric Series and the Salgir sequence of the Eski-Orda Series confirms the facial character of the primary relationships of these series. The studied Upper Triassic sandstones had a common source area and were most likely formed in different parts of the same sedimentary basin. It is most likely that this sedimentary basin was part of the continental margin of Baltica. The presence of a significant number of very ancient detrital zircons (>3.0 Ga, including three oldest detrital zircons grains with ages of ~3.9 Ga) in samples suggests that the crystalline complexes represented in the present-day structure of the Ukrainian Shield had very likely been primary sources of these zircons. Crystalline complexes with such ancient ages are extremely rare over the world, but are widely represented in the Podolian and Azov blocks of the Ukrainian Shield.

Stratigraphic Correlation of Permian–Triassic Red Beds, Moscow Basin, East European Platform: First Detrital Zircon U–Pb Dating Results

The results of U–Th–Pb LA-ICP-MS dating of detrital zircons collected from the Permian–Triassic red beds of the Moscow Basin are presented. U–Th–Pb ages of detrital zircons from two samples (Upper Permian and Lower Triassic), which were collected in the vicinity of the P–T boundary in the Zhukov Ravine reference section, show their contrasting provenance. It means that U–Pb detrital zircon geochronology can be used as an additional independent tool for stratigraphic correlation of the Permian–Triassic red beds, at least within the Moscow Basin. The applicability of the method is illustrated by additional constraints on the age of the Nedubrovo member deposits (Vologda Region) with a previously uncertain stratigraphic position: the U–Pb age pattern of the respective detrital zircons suggests their Early Triassic age.

Detrital zircon provenance evidence for an early Permian longitudinal river flowing into the Midland Basin of west Texas

ABSTRACT Collision of Gondwana and Laurentia in the late Palaeozoic created new topography, drainages, and foreland basin systems that controlled sediment dispersal patterns on southern Laurentia. We utilize sedimentological and detrital zircon data from early Permian (Cisuralian/Leonardian) submarine-fan deposits in the Midland Basin of west Texas to reconstruct sediment dispersal pathways and palaeogeography. New sedimentological data and wire-line log correlation suggest a portion of the early Permian deposits have a southern entry point. A total of 3259 detrital zircon U-Pb and 357 εHf data from 12 samples show prominent groups of zircon grains derived from the Appalachian (500–270 Ma) and Grenville (1250–950 Ma) provinces in eastern Laurentia and the peri-Gondwana terranes (800–500 Ma) incorporated in the Alleghanian-Ouachita-Marathon orogen. Other common zircon groups of Mesoproterozoic-Archaean age are also present in the samples. The detrital zircon data suggest throughout the early Permian, Appalachia and Gondwana detritus was delivered by a longitudinal river system that flowed along the Appalachian-Ouachita-Marathon foreland into the Midland Basin. Tributary channels draining the uplifted Ouachita-Marathon hinterland brought Gondwana detritus into the longitudinal river with headwaters in the Appalachians or farther northeast. This drainage extended downstream westward and delivered sediments into the Permian Basin near the west terminus of the Laurentia-Gondwana suture. Estimated rates of deposition and proportions of zircons from more local (Grenville) versus more distal (Pan-African) sources indicate that river strength decreased throughout early Permian time. Primary sediment delivery pathway was augmented by minor input from the Ancestral Rocky Mountains and wind deflation of fluvial sediments north and east of the basin. Slope failure associated with early Permian deposition in the southeastern margin of the Midland Basin triggered gravity flows leading to submarine fan deposition.

Triassic formations of Mountain ous Crimea: the first resust of U–Pb dating of detrital zircons

The first results of U-Pb dating of detrital zircons (dZr) from two samples characterizing the Taurica and Eski-Orda Groups of the Cimmerian structural complex of the Mountainous Crimea are presented. The strong similarity of the sets of ages of dZr from the Lower Taurica Formation of the Taurica Group and the Salgir strata of the Eski-Orda Group confirms the facial character of the primary relationships of these Groups. The studied Upper Triassic sandstones had a common feeding province and were formed, most likely, in different parts of the same sedimentary basin. It is most likely that this sedimentary basin was part of a continental margin of Baltica. The presence in samples of a significant number of dZr with very ancient ages >3.0 Ga (including 3 the oldest dZr grains with ages of ~3.9 Ga) makes the crystalline complexes represented in the present-day structure of the Ukrainian Shield as the very possible primary sources of these zircons. Crystalline complexes with such ancient ages are extremely rare over the world, but are widely represented in the Podolian and Cis-Azov blocks of the Ukrainian shield.

Surface microtextures and new U–Pb dating of detrital zircons from the Eocene Strihovce sandstones in the Magura Nappe of the External Western Carpathians: implications for their provenance

Heavy mineral morphological, chemical and isotopic features are strong discriminative parameters in provenance studies. This paper focuses on the micro-textural signatures of detrital zircon grains obtained by scanning electron microscope (SEM) and U–Pb geochronological dating from the Strihovce Formation sandstones of the Magura Nappe in the External Western Carpathians. Our focus provides an important contribution to understanding the provenance of these sedimentary rocks. Although the SEM images reveal few dissolution features, they highlight many marks of mechanical processes which occur during detrital zircon transport. The detrital zircon U–Pb ages range from Mesoarchean–Neoproterozoic through Cambrian to Permian and Late Cretaceous. The pronounced peak at approximately 480 Ma Ordovician indicates the culmination of the peri-Gondwanan magmatic event. In conjunction with Archean to Proterozoic zircon inheritance, it implies Cadomian affinity of the potential source terranes which supplied the Magura Basin. The approximate ages of 379 Ma for the Late Devonian peak and 264 Ma for the Permian relate to widespread magmatism and/or rhyolite volcanism. These sources could be associated with the Carpathian basement units and the Apuseni terranes of the Tisza/Dacia mega-units. Most importantly, the sub-hedral Proterozoic zircons may signal the input of ‘first-cycle’ material from relatively closer surroundings, including the South-Magura Ridge to the Magura Basin.

U–Pb dating of detrital zircons in the eastern Guangdong Basin, South China, and constraints on the tectonic transformation from the Early to Middle Jurassic

Controversies exist regarding the mechanism of formation of basins located on the continental margin of South China as well as when they formed. It was ascertained based on clastic petrology, geochemical analysis, and zircon U–Pb dating that the sedimentary provenances in the eastern Guangdong Basin are mainly felsic igneous rocks from the late Early Jurassic to the Middle Jurassic. The late Early Jurassic Qiaoyuan Formation mainly shows major age peaks at approximately 238 Ma, 259 Ma, and 1858 Ma, and the Middle Jurassic Tangxia Formation shows major age peaks at approximately 169 Ma and 172 Ma. From the late Early Jurassic to the Middle Jurassic in the eastern Guangdong Basin, the source region changes from southwestern South China and southern South China to the eastern Nanling Range. It was determined by comparing the detrital zircon ages of the Qiaoyuan Formation and the Tangxia Formation with those of the late Paleozoic to early Mesozoic basins, and analyzing both the geochemical data and sedimentation, that the eastern Guangdong Basin changed from the basin-arc foreland basin of the late Early Jurassic to the back-arc extension basin of the Middle Jurassic. The changes in early Mesozoic detrital zircon age peaks indicate that the tectonic regime of the eastern Guangdong Basin ended the transformation from the Tethyan tectonic domain to the paleo-Pacific tectonic domain in the early Middle Jurassic (approximately 172 Ma).

Paleoproterozoic and Neoproterozoic Quartzites of the Kyrgyz North Tianshan: Age Determination according to the Results of Detrital Zircon Dating

LA-ICP-MS U–Pb dating of detrital zircons reveals two levels of accumulation of Proterozoic quartzites in the Kyrgyz North Tianshan. The quartzites of the Makbal Formation in the core of the Makbal anticlinorium have a maximum depositional age of 1.7 Ga and characterize the oldest stage of accumulation of quartzites in the western Central Asian Orogenic Belt. Quartzites of the Ovva Formation in the northeastern limb of the Makbal anticlinorium and Djeldysu Formation in the Burkhan anticlinorium have maximum depositional ages of ca. 1.0 Ga. Distributions of detrital zircon ages in these two formations are identical and indistinguishable from detrital zircon age distributions in the Neoproterozoic quartzites of the North Kazakhstan. The latter three quartzitic units have common provenance and, apparently, represent the same stratigraphic level. Distinctly different distributions of detrital zircon ages indicate that Precambrian microcontinents of the Kokchetav-North Tianshan zone represented independent continental massif with respect to Precambrian crustal blocks of the Middle Tianshan and Tarim Craton.

Northern limit of Gondwana in northwestern Mexico from detrital zircon data

UPb geochronology along a north-south transect from central Sonora to northern Sinaloa in northwestern Mexico indicates several changes in provenance sources through time and space. Lower Cambrian arenites of the Proveedora Quartzite yield a single main age peak at 1075 Ma with minor Paleoproterozoic contribution. Arenites from the Sonobari Complex of southwestern Sonora-northwestern Sinaloa, purportedly assigned to the early Paleozoic, yield main peaks at 1424, 1662, and 1736 Ma, probably derived from the Yavapai and Mazatzal provinces, which are pervasively intruded by early Mesoproterozoic granites coeval to those forming the Granite-Rhyolite Province. Lower to Upper Ordovician units deposited on shelf, slope, and abyssal environments display very similar zircon age patterns, with main peaks ca. 2700 and 1850 Ma, indicating a large drainage system arising from the Archean cratons of Laurentia such as the Wyoming or Superior Provinces, and Paleoproterozoic sources similar to the Trans-Hudsonian orogen, which are older than the Yavapai Province. The Río Fuerte quartzites from southern Sonora-northern Sinaloa contain main peaks at 534, 542, and 637 Ma whose sources may be peri-Gondwanan blocks similar to Avalonia or Carolina terranes. A minor peak at 475 Ma suggests input from igneous suites reported from the Acatlán Complex in southern Mexico. UPb geochronology permit inference of a late Paleozoic collisional orogen in northwestern Mexico that was originated by the collision of Gondwanan blocks against southern Laurentia and outline the boundary between terranes related to continental blocks in the Pangaea supercontinent.