Gondwana Research最新文献

{"title":"Chemical, biochemical and environmental DNA analysis of sediments from two seamounts of the deep Arabian Sea","authors":"K. Devika Raj ,&nbsp;Anas Abdulaziz ,&nbsp;C. Jasmin ,&nbsp;M.J. Navya ,&nbsp;Silpa Chandran ,&nbsp;Nizam Ashraf ,&nbsp;Anoop Krishnan ,&nbsp;K.U. Abdul Jaleel","doi":"10.1016/j.gr.2025.06.013","DOIUrl":"10.1016/j.gr.2025.06.013","url":null,"abstract":"<div><div>This study examines the chemical and biochemical properties, as well as the benthic diversity, of seamounts in the Arabian Sea, with a focus on SMS2 and SMS3, located along the Laccadive Ridge in the deep Arabian Sea. The summits of these seamounts interact with oxygen minimum zones (OMZs) at 340 – 440 m, potentially shaping their unique biochemical properties and biodiversity. Sediment collected from the summit of these seamounts revealed significant concentrations of iron (SMS2: 6889 ppm, SMS3: 4888 ppm), manganese (SMS2: 48 ppm, SMS3: 39 ppm), nickel (SMS2: 42 ppm, SMS3: 36 ppm), vanadium (SMS2: 40 ppm, SMS3: 31 ppm), chromium (SMS2: 40 ppm, SMS3: 26 ppm) and zinc (SMS2: 32 ppm, SMS3: 20 ppm). The organic matter present in the sediments is predominantly refractory, characterized by a high carbon-to-nitrogen ratio (SMS2: 30.4, SMS3: 51.2) and low protein content (SMS2: 1131.5 µg g⁻¹, SMS3: 701.0 µg g⁻¹). The study employs environmental DNA (eDNA) techniques to reveal the benthic diversity of these seamounts, which is largely comprised of eDNA signatures from Annelids, Arthropods, and Cnidarians that thrive in low-oxygen, iron-rich environments. This research emphasizes the role of OMZs and geochemical factors in shaping biodiversity and ecological processes on seamounts. Furthermore, the regional variability in heavy metal composition and organic matter dynamics reflects distinct oceanographic conditions across these seamounts. Overall, the findings offer valuable insights into the biochemical composition, benthic biodiversity, and ecological significance of seamounts in the southeastern Arabian Sea, underscoring the necessity for broader investigations to enhance our understanding of deep-sea ecosystems.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 137-146"},"PeriodicalIF":7.2,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cambrian–Triassic mafic magmatism in the northeastern Pamir: Implications for the transition from the Proto- to Paleo- Tethys oceans","authors":"Zhihao Song ,&nbsp;Chuanlin Zhang ,&nbsp;Yan Jing ,&nbsp;Masumeh Sargazi ,&nbsp;Hongran Wang ,&nbsp;Xiaoqiang Liu ,&nbsp;Xiantao Ye","doi":"10.1016/j.gr.2025.06.014","DOIUrl":"10.1016/j.gr.2025.06.014","url":null,"abstract":"<div><div>The Pamir Plateau records the evolution of the Tethys Ocean, assembly of the main terranes of the Gondwana land, and transition from the Proto- to the Paleo-Tethys tectonic domains. In this study, newly identified multi-stage mafic intrusions in the northeastern Pamir we investigated to better elucidate these processes. Zircon U–Pb dating identified four stages of mafic magmatism: 539–512 and 211 Ma in the Northern Pamir Terrane (NP), and 277 and 206 Ma in the Central Pamir Terrane (CP). The 539–512 Ma gabbros in the NP have arc-like geochemical compositions, characterized by enrichments in large-ion lithophile elements (Rb, Ba, and Sr) and depletions in high-field-strength elements (e.g., Nb, Ta, and P). They have relatively uniform zircon ε_Hf(t) values (−2.7 to +2.3), elevated zircon δ¹⁸O values (5.97 ‰–7.66 ‰), and negative ε_Nd(t) values (−6.88 to −2.33). These gabbros were likely derived by partial melting of metasomatized sub-continental lithospheric mantle in a continental arc setting. The magmas then experienced significant assimilation and fractional crystallization processes. The <em>ca.</em> 211 Ma cumulate gabbros have ocean island basalt (OIB)-like compositions, mantle-like zircon δ¹⁸O values (5.05 ‰–6.69 ‰), and positive ε_Nd(t) values (+0.37 to +4.21), indicative of derivation from a water-rich asthenospheric mantle source in a subduction setting. The 277 Ma gabbros in the CP exhibit enrichments in light rare earth elements, and variable whole-rock ε_Nd(t) values (+1.56 to +4.74) and zircon ε_Hf(t) (−7.3 to +1.6) values, indicating the partial melting of a lherzolitic source in a fore-arc setting. The 206 Ma gabbros in the CP, exhibiting OIB-like elemental signatures and positive ε_Nd(t) values (+1.87 to +1.96), and were likely derived from spinel-facies mantle that had been metasomatized by oceanic crust-derived materials, as evidenced by significant negative Pb anomalies. These results and those of previous studies indicate that southward subduction of Proto-Tethys Ocean in the northeastern Pamir region began at <em>ca.</em> 540 Ma. The Proto-Tethys oceanic slab was subducted beneath the Mazar–Tianshuihai Terrane until the Late Ordovician, but the ocean did not close completely, leaving a remnant basin that was infilled by the Upper Ordovician–Lower Carboniferous clastic carbonate sedimentary rocks. The initial subduction of Paleo-Tethys Ocean began at <em>ca.</em> 330 Ma in the Pamir, as recorded by the Qushiman ophiolite in the NP and back-arc volcanic rocks between the Tarim and NP. The 277 and 206 Ma gabbros in the CP suggest that bi-directional subduction of Paleo-Tethys Ocean in the Pamir began before <em>ca.</em> 277 Ma. Finally, <em>ca.</em> 180 Ma granulite-facies metamorphism occurred during final closure of the Paleo-Tethys Ocean in the Pamir, due to the collision between the NP and CP.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 98-118"},"PeriodicalIF":7.2,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fault timing and depocentre development in the northern Perth Basin during the evolution of the East Gondwana rift","authors":"Christopher Watts ,&nbsp;Chris Elders ,&nbsp;Mitchell O’Mara ,&nbsp;Nicholas E. Timms ,&nbsp;Hugo K.H. Olierook","doi":"10.1016/j.gr.2025.06.011","DOIUrl":"10.1016/j.gr.2025.06.011","url":null,"abstract":"<div><div>Despite renewed interest in the energy resources of the Perth Basin, rift propagation, the evolution of fault activity and depocentre development along the Western Australian margin during rifting of East Gondwana are not well established. Rifting resulted in a series of predominantly NNW–SSE trending graben and half-graben extending from the Southern Carnarvon Basin in the north, through to the Perth Basin in the south. Gravity and magnetic data indicate two regions of greater structural complexity along this margin, with the northern of these regions data-poor. We investigate the more southerly region, commonly referred to as the northern Perth Basin, a Paleozoic to Mesozoic depocentre that developed through multiple phases of extension with variable extension directions, recording intracontinental rifting and eventual break-up of Australia and Greater India as part of the East Gondwana interior rift. Recently acquired seismic surveys that better image the pre-Mesozoic stratigraphy, together with legacy seismic and well data, have been utilised to create composite sections perpendicular and parallel to the rift axis. These composite sections reveal a progressive southward shift in fault activity and depocentres from the late Carboniferous through to the Early Cretaceous and that towards the south, many of the N–S trending fault segments previously thought to be active during the Cisuralian (early Permian) initiate much later in the Jurassic or Cretaceous. By contrast, E–W trending faults in the north of the basin, which formed perpendicular or at high angles to the rift axis, become throughgoing faults during the Late Triassic to Early Jurassic. Ultimately, these new interpretations provide evidence for episodic propagation of the rift system toward the south.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 147-163"},"PeriodicalIF":7.2,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Northeastern Indian origin of the Lhasa terrane","authors":"Guang-Xu Wang ,&nbsp;Ren-Bin Zhan ,&nbsp;Jisuo Jin ,&nbsp;Zhong-Yang Chen ,&nbsp;Ian G. Percival ,&nbsp;Xin Wei ,&nbsp;Yan Liang ,&nbsp;Yu-Nong Cui ,&nbsp;Yong Wang ,&nbsp;Ya-Tao Zhang","doi":"10.1016/j.gr.2025.06.010","DOIUrl":"10.1016/j.gr.2025.06.010","url":null,"abstract":"<div><div>The Lhasa terrane, once part of Gondwana until the Permian/Triassic, rifted away and accreted to Eurasia, forming a core part of the Tibetan Plateau. Pinpointing its palaeogeographical position is essential for understanding both the reconstruction of Gondwana and the plateau’s evolution. However, considerable controversy persists over its exact position before separation, with geochemical and isotopic data suggesting ties to Australian, Indian or African sections of eastern Gondwana. Here, we use newly acquired, palaeobiogeographically sensitive fossils from the Baingoin area of central Tibet to determine the terrane’s affinities. This late Darriwilian–Sandbian (Middle–Late Ordovician, ca. 457–453 Ma) biota lay along a palaeolatitudinally differentiated biotic gradient, indicative of a distinctly closer palaeobiogeographical affinity to northeastern India than to Australia or Africa. This finding, confirmed by a critical review of existing fossil and geochemical data, strongly supports a northeastern Indian origin of the Lhasa terrane.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 184-191"},"PeriodicalIF":7.2,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144581056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supra-subduction zone magmatism and extreme mantle depletion in the Early Cretaceous Nidar Ophiolite Complex, NW India","authors":"Akinori Sato ,&nbsp;Takeshi Imayama ,&nbsp;Dripta Dutta ,&nbsp;Yasuaki Kaneda ,&nbsp;Shota Watanabe ,&nbsp;Takeshi Hasegawa ,&nbsp;Masayo Minami ,&nbsp;Yuki Wakasugi ,&nbsp;Shigeyuki Wakaki ,&nbsp;Keewook Yi","doi":"10.1016/j.gr.2025.06.015","DOIUrl":"10.1016/j.gr.2025.06.015","url":null,"abstract":"<div><div>The Early Cretaceous Nidar Ophiolite Complex (NOC) in south Ladakh offers key insights into the geodynamic evolution of the Neo-Tethyan Ocean during subduction initiation. Although previously identified as a supra-subduction zone (SSZ) ophiolite, the tectonic connection between the SSZ setting and the former spreading center remains unclear. In this study, new mineral and whole-rock data, Nd-Sr isotopes, and detrital zircon ages from the NOC provide further constraints. The gabbros, with low SiO₂, exhibit ultra-depleted light rare earth elements (LREE) and pronounced negative Nb, Zr, and Ti anomalies, suggesting melting of a highly depleted Jurassic mantle lithosphere during subduction initiation. Dolerites and basalts, with higher SiO₂ and lower CaO, show nearly flat to slightly depleted LREE patterns, indicating normal mid-ocean ridge basalt-like compositions. Fractional crystallization played a key role in forming doleritic and basaltic melts, as indicated by plagioclase zoning and ɛNd (t) values (+7.8 to + 8.7). High-Mg andesites likely formed through second-stage melting of a metasomatized mantle wedge, with later magmatic recharge. Magmatic temperatures of 1065–1080 °C in clinopyroxenes and reverse zoning in plagioclase support this interpretation. The NOC underwent a regional hydrothermal alteration, forming secondary albite, actinolite, epidote, and chlorite. U–Pb zircon ages of 136.2 ± 1.6 Ma constrain the minimum age of subduction initiation. In the Th/Yb–Nb/Yb diagram, NOC samples range from the mantle array to island arc tholeiite, resembling the Spongtang ophiolite but differing from the calc-alkaline series of the Late Cretaceous Dras-Spong arc. The Cretaceous SSZ magmatism in south Ladakh likely reflects the lifecycle of SSZ ophiolites rather than separate subduction zones. The Nidar-Spongtang ophiolites and Dras-Spong arc record magmatic responses to subduction initiation and mature subduction, respectively, within the same island arc complex between 140–78 Ma.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 119-136"},"PeriodicalIF":7.2,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing the spatial spillovers of sustainable development between the eastern and western countries: Analyzing the integrated sustainability perspective","authors":"Jian Li ,&nbsp;Vahid Mohamad Taghvaee","doi":"10.1016/j.gr.2025.05.027","DOIUrl":"10.1016/j.gr.2025.05.027","url":null,"abstract":"<div><div>There are various perspectives of sustainability, including integrated sustainability, weak sustainability, and strong sustainability, complicating the understanding of the perspective fitting the socioeconomic characteristics of each group of countries. To address this research gap, the main objective of the study is to examine the three perspectives of sustainability across the US, China, and Indonesia to reveal their most dominant sustainability perspective. To this end, it maps the spatial spillovers of sustainability pillars, including social, environment, and economy, within the sample countries. For this mapping, this approach estimates the sustainability elasticities using the SEY model, which involves the Vector Autoregression (VAR), simultaneous equations system, and causal examination, within 1974–2020. The results indicate that the elasticities of sustainability are mainly high and synergistic, meaning that the sustainability pillars mainly have considerable and synergistic spillover effects. This finding accepts the integrated sustainability while refusing the perspectives of strong and weak sustainability. Moreover, the findings denote that the flowing patten of spillovers have a spatially symmetric distribution between the US and China, attaching equal importance to the relationships with the western and eastern economies of the world. The theoretical implication of the findings is that they introduce spillovers as the 4th dimension of sustainability, completing the three classical dimensions of economy, environment, and social in the context of the weak and strong perspective of sustainability. From the perspective of policy recommendation, the findings suggest decision-makers in Indonesia to promote peaceful, strong, and balanced ties with the great economic powers in the west and the east like the US and China.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 66-79"},"PeriodicalIF":7.2,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin of superlarge Bayan Obo carbonatite body and its REE-Nb mineralization","authors":"Wenlei Song ,&nbsp;Qian Chen ,&nbsp;Cheng Xu ,&nbsp;Marco Brenna ,&nbsp;Shanna Xue ,&nbsp;Honglin Yuan ,&nbsp;Xuefeng Zhu","doi":"10.1016/j.gr.2025.06.007","DOIUrl":"10.1016/j.gr.2025.06.007","url":null,"abstract":"<div><div>Mantle-derived carbonatites provide the most rare earth element (REE) and Nb metal raw materials for the global market. Among them, the Bayan Obo in China is a huge carbonatite body containing the world’s largest REE and second-largest Nb resources. However, neither the origin of the superlarge carbonatite nor of the REE and Nb mineralization are known. Here, we report the first Bayan Obo primary carbonatites with monazite and columbite U-Pb ages of ca. 1300 Ma. They show moderate REE and relatively high Nb contents and mantle-derived depleted ⁸⁷Sr/⁸⁶Sr_i (0.70255–0.70298), εNd_t (0.2–2.2) isotopic values, distinct from the (ca. 433–408 Ma REE mineralization) banded rocks that have radiogenic Sr isotopes (up to 0.7060). Many REE and Nb minerals are veinlets or overprints in the banded rocks. Two types of δ¹³C (∼−4.2 ‰ and −0.16 – 0.29 ‰) isotopes with less radiogenic Sr (∼0.7030) isotopic values were identified in the carbonatites. They may represent different C sources involving interactions between a subducted C-bearing mantle source and an upwelling Mesoproterozoic plume. Therefore, we infer that the Paleoproterozoic assembly and Mesoproterozoic breakup of the Columbia supercontinent favored precursory mantle carbon enrichment and subsequent melting to generate a giant carbonatite with initial REE and Nb mineralization. External fluid alteration re-enriched REE and remobilized Nb.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"146 ","pages":"Pages 216-227"},"PeriodicalIF":7.2,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonic drivers and melt evolution: Unravelling the genesis of pegmatites in the Eastern Brazilian Pegmatite Province","authors":"Lucas Kenni ,&nbsp;Cristiano Lana ,&nbsp;Ariela Mazoz ,&nbsp;Marco Antônio L. Silva ,&nbsp;Maria Eugênia Souza ,&nbsp;Ricardo Scholz ,&nbsp;Ian Buick","doi":"10.1016/j.gr.2025.06.008","DOIUrl":"10.1016/j.gr.2025.06.008","url":null,"abstract":"<div><div>The Eastern Brazilian Pegmatite Province (EBPP) hosts a diverse array of pegmatites with significant economic and scientific interest, ranging from rare-element pegmatites enriched in Li, phosphate- and boron-bearing assemblages. These pegmatites are closely associated with S-type granites and metasedimentary host rocks, forming complex magmatic-hydrothermal systems. The Urucum and Itatiaia pegmatites exemplify this late-stage magmatic evolution, displaying distinct geochemical and isotopic signatures reflecting their different fractionation degrees, crustal contamination, and parental melt evolution. We investigate their petrogenesis through U-Pb geochronology, trace element geochemistry, and Sm-Nd isotope analyses of apatite, cassiterite, and zircon to refine their genetic relationships with associated granitic systems and assess the role of partial melting, fluid-rock interaction, and post-collisional magmatism in pegmatite genesis. Our results indicate a temporal and genetic decoupling between the pegmatites and their associated granites, with pegmatite crystallisation occurring ∼ 50 Ma after granite emplacement. The EBPP cannot be explained solely by fractional crystallisation but rather involves partial melting and crustal remobilisation during the post-collisional stage. The Itatiaia pegmatite exhibits an evolved geochemical signature, suggesting a distinct melt evolution influenced by crustal contamination, while the Urucum pegmatite retains geochemical characteristics similar to the G3 S-type granites. Nd isotopic data support a Paleoproterozoic crustal source, with pegmatites forming during the post-collisional stage of the Araçuaí orogen (∼530 Ma). The EBPP developed through a multi-stage tectono-magmatic evolution, transitioning from <em>syn</em>-collisional S-type granites at ∼ 580 Ma to post-collisional anorogenic granite and pegmatite formation between 530 and 500 Ma in the core of the Aracuai orogen, SE Brazil. This transition was characterised by anorogenic magmatism and extensional tectonics driven by orogenic collapse, facilitating the generation of highly evolved pegmatitic melts.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 1-15"},"PeriodicalIF":7.2,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Karharbari Formation (late Sakmarian–early Artinskian), India: A biostratigraphic, palaeoclimatic, and vegetational framework for Cisuralian Gondwana correlation","authors":"Debashish Das ,&nbsp;Shreerup Goswami ,&nbsp;Neha Aggarwal","doi":"10.1016/j.gr.2025.06.006","DOIUrl":"10.1016/j.gr.2025.06.006","url":null,"abstract":"<div><div>The Karharbari Formation of Peninsular India, long considered a transitional unit between the Talchir and Barakar formations, is re-evaluated here as a distinct palaeoecological and stratigraphic interval of Late Sakmarian to Early Artinskian age. Integrating megafloral, palynological, petrographic, coal, and lithostratigraphic data, this review synthesizes records from multiple Lower Gondwana coalfields to clarify the formation’s spatial extent, floral composition, and environmental character. Biostratigraphically anchored by the <em>Crucisaccites monoletus</em> Assemblage Zone, the Karharbari strata exhibit strong regional coherence across basins, supported by floral and faunal correlatives in peri-Gondwanan and southern high-latitude Gondwanan settings, including Australia, South Africa, and South America. The vegetation reflects two interrelated ecological domains: a terrestrial forest system dominated by <em>Gangamopteris</em>, <em>Noeggerathiopsis</em>, and early <em>Glossopteris:</em> and a marshy wetland system comprising <em>Schizoneura</em>, <em>Gondwanidium</em>, and lycopsid groundcover. Conceptual models of floral transition, coal petrography, and climatic trajectory illustrate the formation’s role as a post-glacial recovery phase and precursor to widespread <em>Glossopteris</em>-dominated swamps. Collectively, the Karharbari Formation emerges as a regionally mappable, biostratigraphically distinct, and ecologically transitional unit within the Lower Gondwana, offering a valuable reference point for Cisuralian correlations across Gondwana continents.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"147 ","pages":"Pages 16-35"},"PeriodicalIF":7.2,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping a 300-million-year old glacier bed: The Noordoewer section, Orange River, Namibia","authors":"D.P. Le Heron,&nbsp;P. Mejías Osorio,&nbsp;R. Wohlschlägl","doi":"10.1016/j.gr.2025.05.024","DOIUrl":"10.1016/j.gr.2025.05.024","url":null,"abstract":"<div><div>Glacial geomorphological structures produced during the Late Palaeozoic Ice Age (LPIA) of Namibia provide exceptional insight into the flow direction, flow behaviour, and plumbing of subglacial drainage systems in deep time. At Noordoewer (southern Namibia), along the Orange River, a unique and largely undocumented ∼300 Ma assemblage of subglacial structures within the Dwyka Group is investigated. A detailed geological map documents a complex array of both hard- and soft-bed features shaped by the combined action of subglacial abrasion and meltwater. Structures trend parallel to the Orange River, supporting the view that part of its course originated as a Late Carboniferous valley. Key glacial indicators in a hard bedrock area developed on the Nama Group (Ediacaran metasediments) include (i) striated pavements, (ii) multiple roches moutonnées, and (iii) meltwater channels / p-forms. In areas comprising either a veneer or sheet of sandy diamictite, additional soft subglacial bed features are recognised, including (iv) a flute field, (v) soft-sediment striated surfaces (SSSS) and (vi) glaciotectonic structures including deformation bands. Collectively, these six sets of features support a NNW-directed palaeoflow, in direct contrast to previous interpretations of a southward or westward glacial flow down the axis of the Karasburg Basin. Thus, the new findings have broad implications for reconstructing past ice sheet dynamics and interpreting the geological record of glacial landscapes in the Late Palaeozoic record.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"146 ","pages":"Pages 163-172"},"PeriodicalIF":7.2,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}