The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-m...The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-middle Miocene deformed rocks of the inter-Andean valley between the Western and Central Cordilleras of Colombia.However,uncertainty remains about the age of the latest accretionary phases of the Panama-ChocóBlock.Poorly studied late Miocene volcanic rocks within the northern inter-Andean valley may provide key information to constrain the temporality of that final collision.Here,we study the deformational features of the~12-6 Ma extrusive rocks of the Combia Volcanic Province located in the northwestern Andes(Colombia).We present anisotropy of magnetic susceptibility(AMS)data for pyroclastic and volcanic rocks within the AmagáBasin,an inter-Andean depression with Oligocene-middle Miocene sedimentary rocks that recorded NW-SE compression and NE-SW simple shear caused by the Panama-ChocóBlock collision.We identified that the magnetic fabrics of the extrusive rocks of the Combia Volcanic Province reveal flow directions that indicate the occurrence of ancient volcanoes in the central axis of the AmagáBasin.Some of these fabrics do not contain any deformational features,whereas others record the same structural regime as the Oligocene-middle Miocene sedimentary rocks.We infer that variations in the intensity of the deformation promoted late Miocene local fault reactivations that,in contrast to the Oligocene-middle Miocene deformational events,did not affect the entire AmagáBasin.Age differences among the studied sections can also explain the different deformational patterns identified in the basin.Both interpretations suggest that the most significant collisional events of the Panama-ChocóBlock occurred in the Oligocene-middle Miocene,whereas the formation of the Combia Volcanic Province may have either followed or coincided with the latest stages of the accretion.展开更多
The Prydz Bay-Prince Charles Mountains region in East Antarctica constitutes an exceptional geological transect for investigating continental evolution from the Archean to the Phanerozoic and its relationship with sup...The Prydz Bay-Prince Charles Mountains region in East Antarctica constitutes an exceptional geological transect for investigating continental evolution from the Archean to the Phanerozoic and its relationship with supercontinent cycles.This region preserves a complex record of magmatism,metamorphism,and tectonic reworking.Studies by the Chinese National Antarctic Research Expeditions in this region have yielded critical insights into the geological evolution of Antarctica.Key advances over the past decades encompass the elucidation of the Pan-African and Grenvillian tectono-metamorphic history,the delineation of the continent’s crustal and lithospheric architecture,and the identification of extensive ultrahigh-temperature metamorphism and rare mineral assemblages.Despite these advances,many fundamental questions remain unresolved.The spatial and temporal extents of ancient orogenesis are poorly constrained across different crustal blocks,and the tectonic drivers of extreme metamorphism continue to be debated.The role of deep lithospheric architecture in controlling both past orogenic processes and present-day glacial isostatic adjustment remains underexplored.Furthermore,the origins of ancient cratonic nuclei and their constraints on early Earth geodynamics warrant further investigation.Future research should prioritize integrated,multi-disciplinary approaches that combine geological and geophysical analyses.Key objectives include delineating the architecture and evolution of subglacial basement,reconstructing the Phanerozoic uplift and erosion history of the orogens,and evaluating feedback mechanisms among lithospheric evolution,ice-sheet dynamics,and long-term climate.Holistic cross-disciplinary investigations will be essential to unravel the connections between deep Earth processes and surface systems in one of the planet’s most enigmatic and geologically significant regions.展开更多
基金supported financially by the National Natural Science Foundation of China (Grants W2433104 to V.A.P. and42225402 to J.L.)the China Postdoctoral Science Foundation(Grant 2024M753205 to V.A.P.)+4 种基金the Institute of Geology and Geophysics of the Chinese Academy of Sciences (International Fellowship for Postdoctoral Researchers, Grant 2025PD02 to V.A.P.)an association between ECOS-NORD (France)Colciencias/Icetex (Colombia)(Grant C12U01 to M.I.M.)a junior fellowship scheme of Colciencias (Colombia)(Grant 706-2015 to V.A.P.)supported the undergraduate final project of A.T
文摘The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-middle Miocene deformed rocks of the inter-Andean valley between the Western and Central Cordilleras of Colombia.However,uncertainty remains about the age of the latest accretionary phases of the Panama-ChocóBlock.Poorly studied late Miocene volcanic rocks within the northern inter-Andean valley may provide key information to constrain the temporality of that final collision.Here,we study the deformational features of the~12-6 Ma extrusive rocks of the Combia Volcanic Province located in the northwestern Andes(Colombia).We present anisotropy of magnetic susceptibility(AMS)data for pyroclastic and volcanic rocks within the AmagáBasin,an inter-Andean depression with Oligocene-middle Miocene sedimentary rocks that recorded NW-SE compression and NE-SW simple shear caused by the Panama-ChocóBlock collision.We identified that the magnetic fabrics of the extrusive rocks of the Combia Volcanic Province reveal flow directions that indicate the occurrence of ancient volcanoes in the central axis of the AmagáBasin.Some of these fabrics do not contain any deformational features,whereas others record the same structural regime as the Oligocene-middle Miocene sedimentary rocks.We infer that variations in the intensity of the deformation promoted late Miocene local fault reactivations that,in contrast to the Oligocene-middle Miocene deformational events,did not affect the entire AmagáBasin.Age differences among the studied sections can also explain the different deformational patterns identified in the basin.Both interpretations suggest that the most significant collisional events of the Panama-ChocóBlock occurred in the Oligocene-middle Miocene,whereas the formation of the Combia Volcanic Province may have either followed or coincided with the latest stages of the accretion.
基金financially supported by the National Natural Science Foundation of China(Grant nos.U2444210,42172068)the Fundamental Research Funds of the Chinese Academy of Geological Sciences(CAGS)(Grant no.JKYZD202321)geological survey program(Grant no.DD20221810).
文摘The Prydz Bay-Prince Charles Mountains region in East Antarctica constitutes an exceptional geological transect for investigating continental evolution from the Archean to the Phanerozoic and its relationship with supercontinent cycles.This region preserves a complex record of magmatism,metamorphism,and tectonic reworking.Studies by the Chinese National Antarctic Research Expeditions in this region have yielded critical insights into the geological evolution of Antarctica.Key advances over the past decades encompass the elucidation of the Pan-African and Grenvillian tectono-metamorphic history,the delineation of the continent’s crustal and lithospheric architecture,and the identification of extensive ultrahigh-temperature metamorphism and rare mineral assemblages.Despite these advances,many fundamental questions remain unresolved.The spatial and temporal extents of ancient orogenesis are poorly constrained across different crustal blocks,and the tectonic drivers of extreme metamorphism continue to be debated.The role of deep lithospheric architecture in controlling both past orogenic processes and present-day glacial isostatic adjustment remains underexplored.Furthermore,the origins of ancient cratonic nuclei and their constraints on early Earth geodynamics warrant further investigation.Future research should prioritize integrated,multi-disciplinary approaches that combine geological and geophysical analyses.Key objectives include delineating the architecture and evolution of subglacial basement,reconstructing the Phanerozoic uplift and erosion history of the orogens,and evaluating feedback mechanisms among lithospheric evolution,ice-sheet dynamics,and long-term climate.Holistic cross-disciplinary investigations will be essential to unravel the connections between deep Earth processes and surface systems in one of the planet’s most enigmatic and geologically significant regions.
