Southern Margin Research Articles

A dataset of monthly litter recovery from the desert grassland in Southern Tarim Basin during 2010–2020

The Cele National Field Science Observation and Research Station of Desert Grassland Ecosystem of Xinjiang of Chinese Academy of Science (Hereinafter referred to as "Cele Station"), is located on the southern margin of the Tarim Basin bordered to the south by the Kunlun Mountains and to the north by the largest desert in China, the Taklimakan Desert. As a result of simple vegetation community and slow accumulation of soil organic matter, litter serves as an important source of nutrients in this area. Based on the long-term observations of desert plant communities at Cele station, we gathered monthly dynamic data of litter recovery in the desert grassland from Southern Tarim Basin from 2010 to 2020. Based on plant organs (branches, leaves, and fruits), the monthly dynamic data of litter recovery at the observation sites and plots were sorted out, and the annual changes of community and soil nutrients were recorded. Data were compiled in strict accordance with CERN bio-observation specifications. The data has undergone review and quality control by the quality control personnel of the station and sub-center. The results would provide basic data for further study of litter dynamics in the desert grassland from Southern Tarim Basin, and theoretical support for better understanding and assessing nutrient cycling in hyper–arid desert ecosystems.

When a Plateau Suppresses a Plume: Disappearance of the Samoan Plume Under the Ontong Java Plateau

AbstractThe Samoan hotspot generated an age‐progressive volcanic track that can be traced back to 24 Ma at Alexa Bank, but the trace of the older portion (>24 Ma) of the hotspot track is unclear. We show that six seamounts located in and around the Magellan Seamount chain—north of the Ontong‐Java Plateau (OJP)—have ages (87–106 Ma), geochemistry, and locations consistent with absolute plate motion model reconstructions of the Samoan hotspot track in the late Cretaceous, and three additional seamounts have geochemistry and locations consistent with a Samoan origin. However, a large segment of the Samoan hotspot (24–87 Ma) remains unidentified. Absolute plate motion models show that, from ∼60 to 30 Ma, the OJP passed over the Samoan plume. The exceptional thickness of the OJP lithosphere may have largely suppressed Samoan plume melting because the inferred volcanic trace of the Samoan hotspot wanes, and then disappears, on the OJP. Fortunately, 44 Ma volcanism at Malaita Island, located on the southern margin of the OJP, has a location, age, and geochemistry consistent with a Samoan plume origin, and provides a “missing link” bridging the younger and older segments of the Samoan hotspot. Our synthesis of geochemical, geochronological, and plate motion model evidence reveals that Samoa exhibits a clear hotspot age progression for over 100 Myr. Passage of ancient plateaus over young plumes—here called “plume‐plateau” interaction—may be relatively common: the OJP also passed over the putative Rarotonga hotspot, and the Society and Pitcairn hotspots were overtopped by the Manihiki Plateau.

Extensive carbon cycle between peatland and vegetation: Insights from high net primary productivity of the Middle Jurassic in northwestern China

Peatlands have obvious carbon storage capacity and are crucial in mitigating global climate change. As the end-product of peatlands, coals have preserved a large amount of palaeoenvironmental information. The carbon accumulation rate and the net primary productivity (NPP) of coal-forming peatlands can be used as proxies for recovering palaeoenvironments. A super-thick coal seam (42°35′N, 91°25′E) was developed in the Middle Jurassic Xishanyao Formation in the Shaerhu coalfield in the southern margin of the Tuha (Turpan-Hami) Basin, northwestern China. In this study, we use the time series analysis to identify the periods of Milankovitch orbital cycles in the Gamma-ray curve of this super-thick (124.85 m) coal and then use the obtained cycle periods of 405 ka, 173 ka, 44 ka, 37.6 ka, 22.5 ka to calculate the timeframe of the coal-forming peatlands which ranges from 2703.44 to 2975.11 ka. Considering that the carbon content of the coal seam is 78.32% and the carbon loss during the coalification is about 25.80%, the carbon accumulation rate of the targeted coal seam is estimated to be 58.47–64.34 g C/m2·a, and the NPP is estimated to be 252.28–277.63 g C/m2·a. The main palaeoenvironmental factors controlling the NPP of peatlands are CO2 content, palaeolatitude and palaeotemperature. The reduced NPP values of the palaeo-peatlands in the Shaerhu coalfield can be attributed to the mid-palaeolatitude and/or too low atmospheric CO2 contents. To a certain extent, the NPP of palaeo-peatlands reflects the changes in atmospheric CO2, which can further reveal the dynamic response of the global carbon cycle to climate change. Therefore, predicting the level of NPP in the Middle Jurassic and studying the final destination of carbon in the ecosystem are beneficial to understanding the coal-forming process and palaeoenvironment.

Magmatic underplating associated with Proterozoic basin formation: insights from gravity study over the southern margin of the Bundelkhand Craton, India

Abstract. Extension tectonics responsible for intracratonic rift basin formation are often the consequences of active or passive tectonic regimes. The present work puts forth a plume-related rifting mechanism for the creation and evolution of two Proterozoic sedimentary basins outlining the Bundelkhand Craton, namely the Bijawar and Vindhyan basins. Using global gravity data, a regional-scale study is performed over the region encompassing the southern boundary of the Bundelkhand Craton consisting of the Bijawar Basin, Vindhyan Basin, and Deccan basalt outcrops. The gravity highs in the central part of the complete Bouguer anomaly and the upward-continued regional anomaly, derived from global gravity grid data, suggest that the Vindhyan sedimentary basin overlies a deeper high-density crustal source. The deepest interface as obtained from the radially averaged power spectrum analysis is observed to occur at a depth of ∼30.3 km, indicating that the sources responsible for the observed gravity signatures occur at larger depths. The 3D inversion of complete Bouguer anomaly data based on Parker–Oldenburg's algorithm revealed the Moho depth of ∼32 km below the Vindhyan Basin, i.e., south of the craton. The 2D crustal models along two selected profiles showcase a thick underplated layer with a maximum thickness of ∼12 km beneath the southern part of the Bundelkhand Craton. The inferred large E–W-trending underplating and deciphered shallower Moho beneath the regions south of the exposed Bundelkhand Craton point to crustal thinning compensated for magmatic emplacement due to a Paleoproterozoic plume activity below the craton margin.

Middle triassic magmatism in the Afyon Zone of the Anatolides/Eastern Mediterranean: Implications for the extension of the Northern margin of Gondwana and opening of the Inner-Tauride Ocean

The northward subduction of the Paleo-Tethys beneath the southern margin of Laurasia during the Triassic caused the development of an extensional tectonic regime on the northern Gondwana by pull-forces. The Middle Triassic volcanic activity on the passive continental margin of Gondwana can be attributed to this rifting stage. The Afyon Zone represents the deeply buried northern margin of the Anatolide-Tauride Block (ATB), which was rifted from Gondwana in the Triassic by the opening of the southern Neo-Tethys. It is characterized by the existence of widespread Middle Triassic volcanic activity, which unconformably cover deeply eroded pre-Triassic basement. Early Middle Triassic rhyolites and andesites (245.2 ± 2.0 Ma) represent the first stage of the magmatic activity and exhibit a subduction signature, attributed to the former short-lived southward subduction of the Paleo-Tethys beneath northern Gondwana during the Carboniferous. The second stage of magmatic activity is dominated by trachyandesitic volcanic rocks (243.1 ± 1.9–239.2 ± 1.2 Ma) and rhyolites (243.0 ± 2.9–238.2 ± 1.2 Ma), which were generated in a rift setting. The final stage of magmatic activity at the northern margin of the ATB is characterized by extensional anorogenic alkaline rhyolitic volcanism (237.2 ± 2.3–229.4 ± 2.7 Ma), following the earlier stages described. During Middle to Late Triassic, this rifting on the northern Gondwana led to the synchronous opening of the Inner Tauride Ocean in the north and the southern branch of the Neo-Tethys in the south. The generation of these two oceans and the separation of the ATB and Kırşehir blocks from the northern margin of Gondwana should have resulted in the failure of the northern branch of the Neo-Tethys to open as a new oceanic basin.

Geotermalny przepływ ciepła w Portugalii kontynentalnej

Heat flow density measurements in Portugal were made in boreholes used for mining prospecting. Heat flow density values in the sedimentary basins of the western and southern margins of the country were obtained using data from oil or gas prospecting works. Due to the scarcity of data in the central and northern regions of the country, numerical models based on some characteristics of the region were used to obtain more heat flow values. The total of heat flow values used in this work is 69, with 17 values obtained using numerical models, 36 obtained in boreholes and 16 obtained from oil/gas prospecting wells data. The analysis and location of these data allows to define different regions in the territory and characterize them using average values of heat flow density, temperature gradient and thermal conductivity. Statistical values with all the data in the territory are also presented.

Mesozoic crustal growth and recycling along the Southern margin of Eurasia: Magmatic rocks from the Sanandaj-Sirjan Zone of Iran

The Sanandaj-Sirjan Zone of western Iran is characterized by significant Mesozoic magmatic activity (from the early Jurassic to the late Cretaceous), with Cenozoic rocks being less common. Granitoids are prevalent in this zone, displaying A-, I-, and S-type geochemical characteristics. Despite several studies on these granitoids, there are still some questions regarding their sources– especially the S- and A-type granitoids – and the crustal growth and recycling in this zone, which require further studies using isotopes. This study focuses on the Aligoodarz, Kolah-Ghazi, and Golpayegan granitoids from the central SaSZ to better understand crustal growth and recycling in the Sanandaj-Sirjan Zone. The Aligoodarz and Kolah-Ghazi granitoids are identified as S-type granites, showing strong peraluminous signatures. Geochemical evidence suggests a mixture of melts from sub-crustal metasedimentary and meta-igneous sources, with factors such as source diversity and disequilibrium melting contributing to their formation. in contrast, the Golpayegan granitoids exhibit high total alkali (Na2O + K2O) contents and high field strength elements, indicating alkaline magmatic affinity. Their geochemical signatures suggest derivation from an enriched portion of an Indian MORB-like protolith. Golpayegan syenites share similarities with within-plate A1 granites, suggesting they are related to anorogenic silica-oversaturated granitoids. Golpayegan A-type granites probably originated from high-degree fractionation of alkali basic magmas. Golpayegan gabbros may be derived from a MORB or OIB-like mantle source, with characteristics indicating the presence of garnet in the mantle source and potentially deep melting from a mantle plume. Newly compiled zircon UPb data from the Sanandaj-Sirjan Zone show a complex magmatic chronology spanning from approximately 180 million years ago to the Eocene epoch, revealing peaks of magmatic activity at various intervals. Distinct phases of A-, I-, and S-type magmatism are identified, and synthesis of zircon UPb ages and HfO isotope data reveals the simultaneous occurrence of S-type and I-type magmas during specific periods. Furthermore, our study explores the tectonic settings underlying these magmatic processes and proposes scenarios involving subduction, continental rifting, and asthenospheric upwelling to elucidate the geological dynamics of the SaSZ.

Tectonic evolution of the South Tazin Lake shear zone; a major Arrowsmith-age (ca. 2.36 Ga) structure in the SW Rae craton, Laurentia

The Rae Province records the effects of multiple, staggered orogenies along both margins, leaving a complex record of tectonism within major crustal-scale shear zones. While the recently recognized 2.5–2.3 Ga Arrowsmith orogeny is now known to have affected a large tract of the western Rae, few related structures have been described. In this paper, we present the first detailed investigation of such a structure, the ‘South Tazin Lake shear zone’, localized along the Nolan-Zemlak lithotectonic domain boundary in the SW Rae. Multi-scale structural analysis undertaken herein documents the lithostructural zonation and strain progression across this structure and evaluates its context in the regional tectonic evolution. Strain intensity increases dramatically from north to south, with onset of thick, continuous intervals of protomylonite to ultramylonite toward and into a 3–5 km wide corridor that straddles the Nolan-Zemlak domain boundary and constitutes the core of the shear zone. New U-Pb zircon igneous crystallization ages are consistent with previous results for units across the Nolan-Zemlak domain boundary while 40Ar-39Ar thermochronology of hornblende and biotite provides temporal constraints on deformation and a more detailed thermal evolution than previous studies. An 40Ar-39Ar date of 2361 ± 12 Ma for hornblende overgrowing the sheared and recrystallized matrix in blastomylonitic rocks places a minimum age on D2 mylonitization. This, together with similar ages in the core of the shear zone from foliation-parallel hornblende, definitively links ductile shearing and the related S2 fabric along the South Tazin Lake shear zone with Arrowsmith orogenesis. Cooling rates suggest an initial accelerated phase (∼2360–2350 Ma) of post-Arrowsmith exhumation, but the absence of extensional shear-sense indicators implies control by structures outside of the immediate area; or masking by younger (Taltson-age) structures. This was likely followed by a much slower erosion-related (≤2.35 Ga) phase. All-told, the South Tazin Lake shear zone represents a significant Arrowsmith-age tectonic front that was reactivated only along its southern margin under ductile–brittle conditions during the ca. 1.93 Ga Taltson orogeny. These dual fronts were later transposed to the northeast in concert with deformation along the Black Bay fault during the ca. 1.90 Ga Snowbird orogeny.

T-t Evolution of the Early Proterozoic Rocks in the Northern Ladoga Region from the Data on U-Pb, Rb-Sr and Sm-Nd Systems in Minerals

This paper presents the results of a study of isotopic systems in minerals and rocks in southern margin of the epi-Archean Karelian craton in the zone of its junction with the Svecofennian mobile belt. U-Pb, Sm-Nd and Rb-Sr mineral ages of metamorphic rocks allowed reconstructing a T-t trend during ~1.88–1.61 Ga, which reflects a wide-ranging cooling history of metamorphic rocks from the peak values of about 650–700 °C at 1.88–1.79 Ga (U-Pb age of monazites and apparent oldest Sm-Nd age of amphiboles) to 300–400 °C at 1.61 Ga (model Rb-Sr age of biotites) in zones of low- and medium-temperature metamorphism. The specificity of removal of deep-seated rocks to the present-day erosion surface and the reconstructed T-t trend comply with the development of thrust-nappe structures during the exhumation of the Svecofennids. It is also assumed that differential vertical block movements played a significant role during the post-orogenic extensional collapse and neorifting.

Statement of Retraction: Environmental significance of Palaeogene gastropod fossils in the southern margin of the Junggar Basin

Statement of Retraction: Environmental significance of Palaeogene gastropod fossils in the southern margin of the Junggar Basin

Upper Triassic igneous rocks of the southern Kenai Peninsula, Alaska—prelude to Early Jurassic subduction along the Western Wrangellia composite terrane margin

New U–Pb zircon geochronology identifies a latest Triassic (ca 214–201 Ma) igneous suite of tuff, hypabyssal dikes, and a pluton on the southern Kenai Peninsula, Alaska. The igneous suite was emplaced within Upper Triassic sedimentary rocks along the southern margin of Western Wrangellia, the western-most fragment of the Wrangellia composite terrane. The igneous rocks range from mafic (50.6% SiO2) to felsic (78.3% SiO2), characteristically have less than 1.55% K2O, and generally have low trace element abundances. The tonalitic and trondhjemitic magmas were largely sourced in mafic-rich lower crust and incompletely assimilated quartz and other mineral xenocrysts are common. Fractionation involving plagioclase and amphibole is indicated for some magmas and composite intrusions and igneous xenoliths indicate magma mixing was possible. Paleozoic and Precambrian inherited zircons and initial 87Sr/86Sr (0.704103–0.705609) and 143Nd/144Nd (0.512396–0.512777) ratios indicate that the Western Wrangellia crustal sources are heterogeneous and contain sialic components. The latest Triassic magmatism reflects processes that preceded Early Jurassic subduction along the Wrangellia composite terrane and Pacific Ocean plate boundary. These processes involved heating and melting of mantle lithosphere and lower crust as mantle instabilities accompanied the breaking of the plate boundary linkages. The Late Triassic transition to subduction along the Wrangellia composite terrane margin coincided with the transition to subduction cessation in the Late Triassic arcs of the western Intermontane terranes of Canada. The shift to subduction along the outboard Wrangellia composite terrane margin marks the beginning of the Pacific Ocean–Cordillera plate interactions that came to dominate the tectonic evolution of the northern Cordillera from the Early Jurassic to today.

Statement of Retraction: Characteristics and environmental significance of upper carboniferous rugose corals in the Qijiagou section, southern margin of the Junggar Basin

Statement of Retraction: Characteristics and environmental significance of upper carboniferous rugose corals in the Qijiagou section, southern margin of the Junggar Basin

Late Pleistocene Fault Slip Rate within the Bole Basin: Insights into deformation kinematics in the Central Tian Shan

Tian Shan is a vast and highly seismically active intracontinental mountain range. GPS measurements and field studies have shown that E-W and NW-SE trending thrusts and fault-related folds are distributed across central Tian Shan. However, few studies have determined the fault and fault-related-fold activity in the Bole Basin, the northernmost part of central Tian Shan. In this study, we focus on the Alashak Fold, which is situated along the southern margin of the Bole Basin. Using high-resolution uncrewed aerial vehicle-Digital Elevation Model data, field observations, and detailed mapping, we determined that the Alashak Fold is characterized by a trishear fault-propagation fold. Along the Alashak River, we identified five levels of fluvial surfaces, the T3 terrace was continuously preserved across the fold. Radiocarbon and surficial 10Be dating were used to determine the exposure age of the deformed T3 terrace. The folding characteristics of T3, trishear inversed modeling, and abandonment age indicate that the Alashak Fault has an uplift rate of 0.8 ± 0.3 mm/yr, a dip-slip rate of 4.2 ± 1.2 mm/yr, and a crustal shortening rate of 4.0 ± 1.2 mm/yr since the late Pleistocene, respectively. The Alashak and Latgan Faults intersect at a depth of 1.2 km, enclosing a wedge-shaped block. Our study emphasizes that tectonic activity along the southern margin of the Bole Basin has played a significant role in north-south shortening within central Tian Shan, as measured by geological measurements since the late Pleistocene. The Alashak Fault can potentially generate moderate–strong (Mw 5.0–7.0) earthquakes, while the Alashak and Latgan Faults can generate major (Mw 7.2) earthquakes.

Statement of Retraction:A minute freshwater pycnodont fish from the Late Cretaceous on the southern margin of the Junggar Basin: Palaeoecological implications

Statement of Retraction:A minute freshwater pycnodont fish from the Late Cretaceous on the southern margin of the Junggar Basin: Palaeoecological implications

Statement of Retraction: Characteristics and significance of upper Triassic cod fossils in the Tongchuan area, Southern Margin of the Ordos Basin

Statement of Retraction: Characteristics and significance of upper Triassic cod fossils in the Tongchuan area, Southern Margin of the Ordos Basin

Statement of Retraction: Characteristics and environmental significance of late carboniferous brachiopods within the Qijiagou Area, Southern Margin of the Junggar Basin

Statement of Retraction: Characteristics and environmental significance of late carboniferous brachiopods within the Qijiagou Area, Southern Margin of the Junggar Basin

Mineral Textures and Chemistry Trace the Origin and Transcrustal Evolution of the Sanyuangou Syenite in Southern North China Craton

Abstract Alkaline rocks are widely distributed in various geological environments and are important carriers for exploring the formation and compositional diversity of continental crust. Extensive studies have investigated the processes of mantle melting and crustal differentiation that produced such rocks. However, the potential interaction processes between mantle-derived magma and crust during their formation are poorly constrained. In this study, we focus on a Paleoproterozoic garnet-bearing syenite in the Xiong'er large igneous province (LIP) on the southern margin of the North China Craton through detailed whole-rock and mineral analyses. The high K2O (7.4–8.8 wt %) syenite emplaced at ~1772 Ma with ancient inherited zircon (1800–2800 Ma). The dominant mineral assemblage is composed of clinopyroxene, garnet, and K-feldspar with a small amount of titanite. Complex compositional oscillatory zoning of clinopyroxene and garnet indicates that magma mixing played a significant role in the formation of the syenite. We estimated the major elements composition for melts in equilibrium with clinopyroxene and calculated the clinopyroxene/melt partition coefficients by crystal lattice strain model, thus calculating the trace elements of the equilibrated melts. The equilibrium melts of high Mg# (>85) clinopyroxene have high CaO/Al2O3 (>0.6) and low Hf/Sm (<0.4), which suggests a role for carbonatitic metasomatism of the mantle. The variables La/Yb (24.4–56.1), Dy/Yb (0.8–5.9), and Yb (0.6–10.3 μg/g) indicate that the initial melts were formed by 1% to 2% partial melting of spinel-garnet phlogopite lherzolite. An REE-based model for melts in equilibrium with low Mg# (<85) clinopyroxene indicates that 10% to 30% felsic magma from ancient crust participated in hybridization. In addition to well-documented magma mixing, the oscillatory zoning of garnet is also related to competition with titanite. The initial alkaline magmas have a high water content (~4 wt %), which delays the crystallization of K-feldspar, leading to the enrichment of K2O, until the K-feldspar accumulates in the shallow crust to form the syenite. Magma mixing under an open system further leads to alkalinity enrichment. Magma source and crustal evolution jointly determine the potassium-rich characteristics of syenite. Multiple episodes of magma mixing and fractional crystallization occur in the crust (700–300 MPa), suggesting complex and vertically extensive magma chambers. This study represents the first identification of carbonatitic metasomatism as a mantle source in the Xiong'er LIP. Furthermore, it offers a new perspective on magma mixing between the mantle and crust in transcrustal magmatic systems, contributing to the formation of alkaline rocks.

An end-Permian two-stage extinction pattern in the deep-water Dongpan Section, and its relationship to the migration and vertical expansion of the oxygen minimum zone in the South China Basin

The diversity and last appearance patterns of different taxa, inhabiting varied palaeo-water depths, can provide significant insights into the deterioration process of palaeoecosystems. This paper systematically summarizes the last appearance of the end-Permian planktons (including deep-water, intermediate-water, and shallow-water radiolarians) and benthos (including ostracods, foraminifers, brachiopods and bivalves) from Dongpan, a deep-water section of South China. Results show that the deep-water radiolarian Albaillellaria was the first order to go extinct, quickly followed by the intermediate- and shallow-water radiolarians and bottom-water ostracods and foraminifers. This was followed by the extinction of the bottom-water brachiopods and bivalves. We propose that the two-stage extinction pattern was related to the end-Permian migration and vertical expansion (both upward and downward) of an oxygen minimum zone (OMZ) along the southern margin of South China.

Age and composition of perovskite in ultramafic lamprophyres from the Zima alkaline-ultramafic carbonatite complex, the southern margin of the Siberian craton: Petrogenetic implications

This paper presents data on the age and trace element composition of perovskites from dykes of ultramafic lamprophyres (aillikites) of the Zima alkaline-ultramafic carbonatite complex (Bolshaya Tagna and Bushkanay) located within the Urik-Iya graben, Eastern Sayan region, southern margin of the Siberian craton. The studied samples exhibit similar textural and structural features but differ slightly in the mineral composition of the groundmass. They have a porphyritic structure, a massive texture, and consist of olivine macrocrystals embedded in a fully crystallized groundmass composed of perovskite, apatite, spinel, phlogopite, garnet, carbonates, clinopyroxene and other minerals. The macrocrystals quantity varies between 40 and 50 vol%. With the exception of a single sample from the Bushkanay dyke, olivine is entirely replaced by serpentine and/or talc.Perovskites from aillikites of the Bolshaya Tagna intrusion exhibit crystals with normal zoning showing a decrease in Na, REE, and Nb contents with center-to-rim increasing Ca content. In contrast, minerals from the aillikites of the Bushkanay dyke demonstrate reverse zoning, with an increase in Na, REE, and Sr and decrease in Ca contents from the center to the rim. We suggest that during crystallization of perovskites, the magma parental to the aillikites of the Bolshaya Tagna intrusion and the Bushkanay dyke had nearly similar trace element composition, but after crystallization of the cores of perovskite crystals each melt portion evolved independently. The samples from the Bushkanay dyke show an increase in fO2 and the residual magma enrichment in REE, Na, and Sr as evidenced by their elevated contents at the rims of perovskite grains. In the Bolshaya Tagna aillikites after crystallization of perovskite cores, the melt was depleted in REE, Na, and Nb.Based on U-Pb dating of perovskites, the age of aillikites from the Bolshaya Tagna intrusion is 583–654 Ma. Perovskite from aillikites of the Bushkanay dyke is relatively young, with an age of 575 ± 39 Ma. The obtained ages are consistent with the age of formation of Neoproterozoic alkaline-ultramafic carbonatite complexes of the Siberian craton and other occurrences of aillikites in a response to extension of the Rodinia lithosphere.

Triassic-Jurassic evolution of the Dabashan Foreland Basin: Detrital zircon perspectives on the tectonic amalgamation of the South China and North China blocks

The Mesozoic Dabashan Foreland Basin, a result of the Mianlue Ocean closure, formed through the collision and amalgamation of the South China and North China blocks. As such, it contains an important record of the tectonic processes leading to the formation of the Qinling Orogenic Belt; however, the timing of transition from basin to mountainous terrains remains debated. Geochronological studies indicate continental collision occurred in the mid-Permian to early Triassic, while some paleomagnetic data suggest a Middle to Late Jurassic occurrence time. Utilizing detrital zircon geochronology and trace element data, in this paper, we examine Triassic-Jurassic sediment provenance patterns during the evolution of the Dabashan Foreland Basin. Results show that in the Middle Triassic, the north Yangtze Block received detrital input from the southern margin of the North China Block. In the Late Triassic, significant tectonic inversion occurred, with detrital sources from the southern margin of North China Block, North Qinling, South Qinling, and the north Yangtze Block. During the early and Middle Jurassic, detrital sources gradually shifted to a dominance from South Qinling, indicating a phased southward migration of collisional orogenic belt sources. Combining thermal events, crustal thickness variations, and paleomagnetic data, we propose a novel model explaining oblique compression along the north Yangtze Block during the early Mesozoic. This model suggests that the Dabashan Foreland Basin likely predates the Middle Triassic, and we contend that crustal deformation and lateral shortening during Mesozoic accretionary orogeny between North China Block and South China Block may explain the debate over collision timing.