Drainage Development Research Articles

Recent and recurrent autopolyploidization fueled diversification of snow carp on the Tibetan Plateau

Abstract Whole-genome duplication (WGD), or polyploidization, is a major contributor to biodiversity. However, the establishment and survival of WGDs are often considered to be stochastic, since elucidating the processes of WGD establishment remains challenging. In the current study, we explored the processes leading to polyploidy establishment in snow carp (Cyprinidae: Schizothoracinae), a predominant component of the ichthyofauna of the Tibetan Plateau and its surrounding areas. Using large-scale genomic data from isoform sequencing, we analyzed ohnolog genealogies and divergence in hundreds to thousands of gene families across major snow carp lineages. Our findings demonstrated that independent autopolyploidization subsequent to speciation was prevalent, while autopolyploidization followed by speciation also occurred in the diversification of snow carp. This was further supported by matrilineal divergence and drainage evolution evidence. Contrary to the long-standing hypothesis that ancient polyploidization preceded the diversification of snow carp, we determined that polyploidy in extant snow carp was established by recurrent autopolyploidization events during the Pleistocene. These findings indicate that the diversification of extant snow carp resembles a coordinated duet: first, the uplift of the Tibetan Plateau orchestrated the biogeography and diversification of their diploid progenitors; then, the extensive Pliocene-Pleistocene climate changes acted as relay runners, further fueling diversification through recurrent autopolyploidization. Overall, this study not only reveals a hitherto unrecognized recent WGD lineage in vertebrates but also advances current understanding of WGD processes, emphasizing that WGD establishment is a non-stochastic event, emerging from numerous adaptations to environmental challenges and recurring throughout evolutionary history rather than merely in plants.

Using detrital zircon U[sbnd]Pb geochronology to track the provenance of Miocene sediments in the northern Pearl River Mouth Basin, South China Sea

The Late Cenozoic provenance study of the Pearl River Mouth Basin (PRMB) holds significant implications for understanding the tectonic-climatic interactions, drainage evolution, and oceanic circulation in the northern South China Sea. However, the Miocene sediment routing system remains poorly understood due to the paucity of zircon geochronological data and the effects of sediment mixing and homogenization. This study reconstructs the ancient source-to-sink system by means of detrital zircon analyses from the northern PRMB and zircon age-based mixture modeling of well-defined provenance end-members. The results disclose varied and complex source-to-sink scenarios since the Early Miocene, involving three primary contributors: the Pearl River drainage system, coastal SE China, and Taiwan Island. In combination with seismic facies and climatic proxies, the intensive addition of Precambrian zircons suggests that, during the Middle and Late Miocene, progressive drainage expansion within the Yangtze Block likely contributed to the increasing sediment supply from the western Pearl River drainage system. Furthermore, the provenance shift in the northern PRMB, as indicated by the Mesozoic ages, may reflect a response to the activation of oceanic circulation and intensification of the East Asian monsoon. Additionally, though less significant, contributions from the Hainan and Luzon Island are also observed, indicating the input of the branch of the Kuroshio Current during the Late Miocene.

Westward Migration of the Chenghai–Jinsha Drainage Divide and Its Implication for the Initiation of the Chenghai Fault

The Chenghai Fault in the Chuan–Dian block terminates at the northwestern segment of the Red River Fault, and is a significant seismogenic structure. The kinematic evolution of this fault should be closely related to the regional tectonic deformation. However, it is difficult to obtain information on structural deformation of the Chenghai Fault due to the large amount of precipitation and well-developed vegetation. The Chenghai normal faulting may drive drainage reorganization in this region, which provides a new perspective for reconstructing and evaluating the tectonic history. High-resolution digital elevation models (DEM) obtained by remote sensing greatly facilitate the study of drainage evolution and active tectonics. We use two methods (χ-plot and Gilbert metrics) to measure the drainage divide stability based on the ALOS DEM (12.5 m resolution) and further reproduce the drainage evolution process in response to the asymmetric uplift by numerical modeling. The results show that the Chenghai–Jinsha drainage divide, hosted by the footwall block of the Chenghai Fault, is migrating westward (away from the Chenghai Fault) and will continue moving ~2.2–3.5 km to reach a steady state. Its migration is controlled by the Chenghai normal faulting. The Chenghai–Jinsha drainage divide formed close to the Chenghai Fault’s surface trace and continues to migrate westward in response to the asymmetric uplift. It only took a few million years for the Chenghai–Jinsha drainage divide to migrate to its current location based on the numerical modeling. The restoration of the drainage reorganization implies that the Chenghai Fault initiated in the Pliocene, which probably results from kinematic reversal along the Red River Fault.

Classical solvability to the free boundary problem for a foam drainage equation. II. From the interface to the bottom

We study a nonlinear partial differential equation describing the evolution of a foam drainage in one dimensional case which was proposed by Goldfarb et al. in 1988 in order to investigate the flow of liquid through channels (Plateau borders) and nodes (intersections of four channels) between the bubbles, driven by gravity and capillarity. Its mathematical studies so far are mainly restricted within numerical and particular solutions; as for mathematical analysis of it there are only a few. We prove that the free boundary problem for the foam drainage equation in the region below an interface to the bottom in a foam column admits a unique global-in-time classical solution by the standard classical mathematical method, the maximum principle. Moreover, the existence of its steady solution and its stability are shown.

Classical solvability to the free boundary problem for a foam drainage equation. I. From the top to the interface

We study a nonlinear partial differential equation describing the evolution of a foam drainage in one dimensional case which was proposed by Goldfarb et al. [Izv. Akad. Nauk SSSR Mekh. Ghidk. Gaza 2, 103–108 (1988)] in order to investigate the flow of liquid through channels (Plateau borders) and nodes (intersections of four channels) between the bubbles, driven by gravity and capillarity. Its mathematical studies so far are mainly restricted within numerical and particular solutions; as for mathematical analysis of it there are only a few. We prove that the free boundary problem for the foam drainage equation in the region from the top to the interface in a foam column admits a unique global-in-time classical solution by the standard classical mathematical method, the maximum principle and the comparison theorem. Moreover, the existence of its steady solution and its stability are discussed.

Drainage evolution in porous carbonate terrain in semi-arid environments: The role of tectonics and climatic change – The case study of the Boukadir carbonate platform, Algeria

Porous carbonate terrains are widespread around the Mediterranean area and form non classical karstic landscapes. The related diffuse infiltration is expected to impede karstification and the establishment of dense drainage networks. In such terrain, the effect of tectonics and climate on drainage development and evolution remains poorly understood. To address this issue, we focus on a semi-arid area with a tuffaceous Messinian carbonate platform characterized by a well-established dendritic network in an active tectonic context. The platform is situated in the Chélif Basin in Algeria, affected by transpressive deformation in relation to the Africa-Eurasia collision. We combine geomorphological observations with drainage morphometric analyses using satellite images and DEM. The drainage network analysis reveals varying tectonic deformation and morphological anomalies resulting from instability in the drainage systems, expressed through (1) variable platform tilt and (2) the presence of knickpoints and convexities in river profiles. These anomalies are particularly pronounced in the west, where knickpoints are more numerous, and incisions deeper. We relate the origin of the tilt to the differential marl compaction and remobilization, and in the area with the highest tilt a recent propagation of the Boukadir thrust underneath the platform might also play a role. Finally, we propose a general model of drainage evolution which highlights the importance of weathering in the Maghreb area transforming the porous media in an indurated carbonate or calcrete.

The interplay of lithology, tectonics and climate in the morphology of Corsica

The morphology of the landscape on the island of Corsica in the western Mediterranean Sea is transient with a clear topographic asymmetry. The geology of the island can be divided into two units – Hercynian Corsica and Alpine Corsica – with contrasting lithology, climate and structural controls between them. We used topographic analysis to assess the influence of each of these factors on landscape form. Disequilibrium in the landscape is illustrated by analysing χ and Gilbert metrics, which indicate active migration of the drainage divide, along with a new metric that quantifies tributary heights above the main stem channel. The climate in the region has fluctuated dramatically from the Messinian salinity crisis through to Quaternary glaciation. However, analysis of the size and distribution of knickpoints across the island does not reflect specific base-level changes. Instead, the basement structures control valley orientation and the conditioning of the landscape by glaciation exerts strong controls on drainage evolution.

Multi-decadal geochemical evolution of drainage from underground coal mines in the Appalachian basin, USA

Coal mine drainage (CMD) in Appalachia is a widespread source of dissolved metals, SO4, and acidity that can degrade aquatic habitats and water supplies for decades following mine closure and flooding. In the bituminous coalfield of Pennsylvania, the Irwin Coal Basin (ICB) contains a series of partly to completely flooded, abandoned underground mines separated by leaky barriers within the Pittsburgh coal seam. CMD originated throughout the basin from minepool aquifers that formed after mine closures dating from 1910 to 1957. Historical and recent water quality data for eight CMD sites across the ICB, plus mineralogy and cation-exchange capacity of overburden lithologies, were analyzed to quantify important reactants and evaluate spatial and temporal water-quality trends. As overburden thickness and residence time increase along a ~ 50-km flowpath northeast to southwest in the basin, CMD becomes more alkaline, and Na concentrations increase. Since the 1970s, all eight ICB discharges have become less acidic, with exponential decreases in acidity, SO4, and Fe concentrations; only two CMD remain net-acidic (acidic pH at equilibrium). Exponential decay models that include a steady-state asymptote consistent with background groundwater chemistry and siderite equilibrium describe the early-stage, rapid contaminant concentration decay immediately after the “first flush” (initial flooding) and the progressive evolution toward late-stage background conditions. A geochemical evolution PHREEQC model indicates that spatial and temporal trends in pH, net-acidity, SO4, Fe, and major cations could be explained by the continuous dilution of first flush water by ambient groundwater combined with sustained water-mineral reactions involving pyrite and carbonates (calcite, dolomite, siderite) plus cation-exchange by clays (illite, chlorite, mixed-layer illite/smectite). These data and model results indicate that 1) cation-exchange reactions enhance calcite dissolution and alkalinity production, resulting in the evolution of CMD to Na-SO4-HCO3 type waters, and 2) siderite equilibrium could maintain dissolved Fe >16 mg/L over the next 40 years.

Neotectonic impact on drainage development in the Eastern Himalayan foreland basin

The present study intends to divulge the complex drainage evolution in connection to neotectonic controls focusing the Jaldhaka and Raidak River interfluve on the eastern Himalayan Foreland Basin (HFB). It involves analysing the surface and sub-surface changes in the fluvial system's evolution with field and geospatial evidence bearing geomorphic markers, sediment analogy and channel morphological properties. The channel orientation, planimetry and the channel longitudinal process anomaly were attributed solely from the geospatial perspective as surface evidence of neotectonic controls. The results unveil an intense neotectonic control on channel development–from structurally guided channel avulsion that shaped the presently active course of the Torsa River to deformation-guided channel morphological changes. Moreover, relatively higher deflection angles, intense channel sinuosity and tight meandering bends forming along the structural elements symptomizes the structure-controlled drainage development in recent times. Furthermore, sediment analogy from deep well logs and shallow subsurface trenches was analysed to obtain subsidence-driven fluvial sequences and geochronology of sedimentary deformation in channel beds and floodplains. The Optically Stimulated Luminescence (with fading correction) technique-based determination of shallow sub-surface sediment's age indicates occurrences of palaeoseismic events between 1.6 ka (±0.1 ka) and 1.35 ka (±0.2 ka) as well as between 1.35 ka (±0.2 ka) and 1.14 ka (±0.1 ka) had resulted in channel bed sagging while stress impacted the formation of syn-sedimentary folding. The palaeoseismic events that led to relative subsidence are evident in upward sediment stacking (channel fill) sequences being observed at multiple trenches. The deep sub-surface staking of channel floor deposition lenses is also evident of basin subsidence that influenced channel oscillations of reoccupation type.

The Significance of Ancient Buried Landscapes as Natural Geomorphic Experiments

AbstractThere is considerable interest in developing quantitative methods for analyzing present‐day fluvial landscapes with a view to extracting information about tectonic forcing and drainage evolution, together with the influence of lithologic substrates and of paleoclimatic variations. In view of the multifactorial nature of this complex problem, it has previously been proposed that natural geomorphic experiments could play a significant role in developing a quantitative understanding of landscape growth and decay. Here, we describe and analyze a stacked sequence of five buried transient landscapes that punctuate marine strata along the fringes of the North Atlantic Ocean. We propose that these landscapes constitute a suite of natural experiments, which illuminate significant aspects of quantitative fluvial geomorphology. Our preliminary analysis of four of these buried landscapes suggests that the amplitude of external tectonic forcing plays a significant role in fluvial landscape evolution. In future, we hope that this suite of natural experiments will be further exploited by the fluvial community with a view to identifying the most appropriate analytical techniques.

Detrital zircons and heavy minerals from the Palu Formation, Sulawesi, Indonesia: constraints on exhumation of the Palu Metamorphic Complex and drainage evolution

The Palu Formation, previously known as the Celebes Molasse in the Palu area, is understudied and was previously considered to be associated with the Pliocene collision between an Australian-derived microcontinent (Banggai Sula) and the eastern margin of Sundaland (West Sulawesi). Here, we present sedimentological, heavy mineral and zircon geochronological data to provide insights into sediment provenance and to elucidate Neogene tectonic activity in Sulawesi. These analyses suggest that the Pleistocene Palu Formation comprises synorogenic alluvial fan to braided river deposits that record the rapid uplift of metamorphic and granitoid rocks in the Neck and west Central Sulawesi. The Palu Formation is characterized by predominant granitoid and metamorphic clasts and heavy mineral assemblages dominated by pyroxene, amphibole and garnet. Detrital zircons record youngest grain ages of c. 2.5 and 3.0 Ma with a significant Pliocene age population and subsidiary Eocene, Cretaceous, Jurassic and Late Triassic age peaks. Rapid uplift and erosion associated with mountain building shaped the topography and influenced the evolution of Palu River networks. Supplementary material : Complete location, heavy mineral and detrital zircon geochronology datasets are available at https://doi.org/10.6084/m9.figshare.c.7033388 Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change

Fluvial geomorphology of the Yan Shan in North China: Implications for drainage evolution and seismic activity

With an average elevation of ∼850 m, the east-trending Yan Shan bounds the North China basin to the south and terminates at the Shanxi rift system and Bohai Sea to the west and east. Although the North China basin and the Shanxi rift system host active faults expressed by repeated occurrences of devastating earthquakes in the historical and instrumental records, the Yan Shan region appears to be stable with low seismicity. In this study, we systematically analyze the morphologic parameters of fluvial systems draining across the Yan Shan to explore whether the low seismicity is a transient phenomenon in the past few decades, or it has previously undetected active faults capable of generating devastating earthquakes impactful to regional communities. As shown in this work, the morphometric indices of the fluvial channels across the central Yan Shan display quasi-equilibrium longitudinal profiles, indicating a long-term lack of geomorphological disturbances by active faulting and strong earthquakes. High normalized steepness indices (ksn) values and hillslope gradients are concentrated along the southern margin of the Yan Shan. This finding can be explained by the ranging-bounding faults, which are kinematically linked with active northeast-striking right-slip faults to the south in the North China basin. The river longitudinal profile of the Luan River, the trends in watershed migration revealed by Chi(χ) indices, the monadnock phase in the upstream of the Luan River indicated by the low HI value, the present-day drainage pattern, and sedimentary records of the Upper Miocene strata are consistent with an interpretation that the upstream of the Luan River was captured by the proto-Luan River as a result of its headward erosion since the Pliocene.

Evaluation of the Neogene depositional dynamics in the Malay-Tho Chu Basin based on seismic analysis: effects of local and regional tectonism and paleoclimatic variations

Depositional environments in areas located near sea level are vulnerable to even subtle changes in both tectonism, climate and eustatic sea level. Sorting out mechanisms behind depositional changes in inner shelf-margins and epeiric seas is therefore far from straight forward. The epeiric Malay-Tho Chu Basin, located in the shallow Gulf of Thailand offshore Vietnam, contains a thick uppermost Oligocene to Recent post-rift succession. Based on 18000 km of 2D seismic profiles, the uppermost Oligocene-Recent succession is subdivided into six seismic sequences. Seismic facies mapping of each sequence complemented by information from industry completion reports of 14 wells document a gradual increase in marine influence from latest Oligocene through Middle Miocene time. The increased marine influence reflects the propagation and opening of the southwestern spreading arm of the East Vietnam Sea (South China Sea (East Sea)) combined with rapid subsidence in the Malay-Tho Chu Basin resulting from fast thermal relaxation following Oligocene rifting and amplified by mild fault-controlled subsidence in especially the western part of the area. From the latest Middle Miocene, slowed subsidence and regression occurred in association with uplift in the nearby southwestern East Vietnam Sea. From the latest Miocene, and during the Pliocene and Pleistocene, subsidence rates increased promoting marine conditions towards the East Vietnam Sea in the southeast. Meanwhile, Mekong River avulsion combined with hinterland uplift stimulated fluvial and alluvial deposition in the northern and western parts of the basin. The long-term depositional pattern was controlled primarily by tectonics, drainage evolution and climate. Meanwhile, flood- and delta plain deposits intercalated with stacked fluvial incisions, often filled by estuarine deposits, document short-lived environmental changes most likely controlled by eustatic sea level fluctuations. Such intervals developed during latest Middle Miocene to Pleistocene periods of slow subsidence or fast depositional rates and are interpreted to be the result of substantial eustatic sea level fluctuations.

Metagenomic insight into the acidophilic functional communities driving elemental geochemical cycles in an acid mine drainage lake

Acidophiles play a key role in the generation, evolution and attenuation of acid mine drainage (AMD), which is characterized by strong acidity (pH<3.5) and high metal concentrations. In this study, the seasonal changes of acidophilic communities and their roles in elemental cycling in an AMD lake (pH∼3.0) in China were analyzed through metagenomics. The results showed eukaryotic algae thrived in the lake, and Coccomyxa was dominant in January (38.1%) and May (33.9%), while Chlorella in July (9.5%). The extensive growth of Chlamydomonas in December (22.7%) resulted in an ultrahigh chlorophyll a concentration (587 μg/L), providing abundant organic carbon for the ecosystem. In addition, the iron-oxidizing and nitrogen-fixing bacterium Ferrovum contributed to carbon fixation. Ammonia oxidation likely occurred in the acidic lake, as was revealed by archaea Ca. Nitrosotalea. To gain a competitive advantage in the nutrient-poor environment, some acidophiles exhibited facultative characteristics, e.g. the most abundant bacterium Acidiphilium utilized both organic and inorganic carbon, and obtained energy from organic matter, inorganic sulfur, and sunlight simultaneously. It was suggested that sunlight, rather than chemical energy of reduced iron-sulfur was the major driver of elemental cycling in the AMD lake. The results are beneficial to the development of bioremediation strategies for AMD.

Neogene drainage reorganization of Longzhong Basin driven by growth of the northeastern Tibetan Plateau: A Sr isotope hydrological perspective

AbstractThe Tibetan Plateau uplift has significantly influenced Asian geomorphic and climate patterns. Drainage evolution across the plateau and its surroundings as the consequence of such changes in landscape and climate provides an opportunity to understand the growth of the Tibetan Plateau. However, the evolution history of major drainage areas around the Tibetan Plateau is largely unknown. Here, we reconstructed the evolution of drainage patterns of the Cenozoic Longzhong Basin in the northeastern Tibetan Plateau since the India–Asia collision using palaeo‐water solute 87Sr/86Sr ratio records from its subbasins. Higher solute 87Sr/86Sr ratios of the Lanzhou and Xining Basins and their consistent temporal variations before ca. 22 Ma as well as lower solute 87Sr/86Sr ratios in the Linxia Basin collectively indicate a relatively steady drainage pattern of the integrated Longzhong Basin. A diverse evolution of the solute 87Sr/86Sr ratio in the Lanzhou and Xining Basins after ca. 22 Ma suggests that there was a drainage reorganization, characterized by the division of one into multiple catchment centres, in response to the growth of the northeastern Tibetan Plateau. Subsequently, the identical solute 87Sr/86Sr ratios in the Lanzhou and Xining Basins were further approached at ca. 16 Ma, and the rise in the solute 87Sr/86Sr ratios of the Linxia and Tianshui Basins occurred at ca. 9–8 Ma, indicating two subsequent changes in solute composition induced by the middle Miocene uplift and late Miocene dust expansion, respectively. Our reconstructions of Cenozoic hydrological evolution in the Longzhong Basin indicate accelerated basin segmentation and drainage adjustment with solute change in response to the growth of the northeastern Tibetan Plateau during the Neogene.

Dynamics Analysis of Droplets Collision with the Wall Driven by Buoyancy

Dynamics analysis of the oil droplet in water impacting on a rigid wall in the range of Re=9.3 ∼ 231.39, We=0.003 ∼ 0.637 was carried out by combining microscopic experiment with theoretical study. In the oil droplet’s force equation, we consider the added mass force and the water film induced force, in addition to the conventional forces, i.e. buoyancy and resistance to flow. Stokes-Reynolds drainage equation (i.e. SR model) and Young-Laplace equation (i.e. YL model) are combined with the force equation to numerically solve the motion law of oil droplets near the wall for different control parameters. The study indicates that coupled model would expect oil droplet velocities, motion trajectories and capture the kinetic behaviors of the water-film drainage evolution. The interfacial deformation of oil droplets causes changes in the pressure and the pressure distribution pattern has an important relationship with the shape of the oil droplet interface. These two forces play a dominant role in droplet motion during the collision and the maximum value of these two forces increases with increasing droplet size and Re number. Future research should shift towards complex oil-water systems and consider the effects of chemicals on oil droplets so that the application of the model will be more generalisable. At the same time, computer technology should be used to transfer the two-dimensional view to a three-dimensional view to analyse the deformation of the oil-water interface and to better understand the drainage process of the water film.

Early Cenozoic Drainage Evolution and Surface Uplift of the Eastern Tibetan Plateau: Insights From the Ninglang Basin

AbstractThe modern high topography of the eastern Tibetan Plateau is drained by several of the largest rivers on Earth, and exerts a prominent influence on the Asian monsoon pattern. However, when the high terrain was formed remains highly debated. Here, we present detrital zircon U‐Pb ages that indicate a south‐flowing drainage system with distal headwaters passed through the Ninglang Basin at ca. 45 Ma. We advocate for early–middle Eocene surface uplift in the Gonjo Basin and areas to the west creating a southeast tilted topography across eastern Tibet. The termination of sedimentation at ca. 40 Ma implies that the river system had deviated from the Ninglang Basin, which we interpret as a result of rise of the Yalong‐Yulong thrust belt. Combined with other lines of evidence from previous studies, we support the establishment of moderate‐high elevation topography of eastern Tibet by late Eocene time.

Examining the effect of ice dynamic changes on subglacial hydrology through modelling of a synthetic Antarctic glacier

Abstract Hydrologic pathways beneath ice sheets and glaciers play an important role in regulating ice flow. Antarctica has experienced, and will continue to experience, changes in ice dynamics and geometry, but the associated changes in subglacial hydrology have received less attention. Here, we use the GlaDS subglacial hydrology model to examine drainage evolution beneath an idealised Antarctic glacier in response to steepening ice surface slopes, accelerating ice velocities and subglacial lake drainages. Ice surface slope changes exerted a dominant influence, redirecting basal water to different outlet locations and substantially increasing channelised discharge crossing the grounding line. Faster ice velocities had comparatively negligible effects. Subglacial lake drainage results indicated that lake refilling times play a key role in drainage system evolution, with lake flux more readily accommodated following shorter refilling times. Our findings are significant for vulnerable Antarctic regions currently experiencing dynamic thinning since subglacial water re-routing could destabilise ice shelves through enhanced sub-shelf melting, potentially hastening irreversible retreat. These changes could also affect subglacial lake activity. We, therefore, emphasise that including a nuanced and complex representation of subglacial hydrology in ice-sheet models could provide critical information on the timing and magnitude of sea-level change contributions from Antarctica.

Cretaceous mountain building processes triggered the aridification and drainage evolution in east Asia

Knowledge of the late Mesozoic topography and drainage system of the Tibetan Plateau is essential for understanding the Cenozoic tectonic dynamics of the plateau. However, systematic analyses of the pre-Cenozoic surface uplift history and sediment-routing systems of the Tibetan Plateau remain sparse. Here we present new results for paleocurrents and U-Pb detrital zircon geochronology from the Lanping Basin, a key junction in the southeastern (SE) Tibetan Plateau, and integrate multidisciplinary data sets to constrain sediment provenance and reconstruct paleotopography and its drainage system throughout the Cretaceous. Our results indicate that mid- to Late Cretaceous (ca. Albian−Santonian) tectonically induced surface uplift occurred in the SE Tibetan Plateau, leading to the build-up of an extensive topographic barrier, and resultant rain shadows in the interior of east Asia. Superimposition of this topographic pattern by uplands in the eastern margin of Asia meant that the Cretaceous topography of east Asia was characterized by an enclosed paleo-relief pattern that was high in both the east and west, with drainage from the east and west to the south, contrasting with previously proposed configurations. This topographic pattern interrupted the atmospheric circulation pattern and generated widespread intracontinental desertification and drainage network evolution in east Asia. Our study constrains a key part of the late Mesozoic growth of the Tibetan Plateau prior to the Cenozoic collision between India and Eurasia and will improve our understanding of the paleoclimate, atmospheric circulation, and modern drainage system evolution of the east Asian continent.

Detrital zircon and apatite U-Pb provenance and drainage evolution of the Newark Basin during progressive rifting and continental breakup along the Eastern North American Margin, USA

Abstract Mesozoic rift basins of the Eastern North American Margin (ENAM) span from Florida in the United States to the Grand Banks of Canada and formed during progressive extension prior to continental breakup and the opening of the north-central Atlantic. The syn-rift strata from all the individual basins, lumped along the entire margin into the Newark Supergroup, are dominated by fluvial conglomerate and sandstone, lacustrine siltstone, mudstone, and abundant alluvial conglomerate and sandstone lithofacies. Deposition of these syn-rift sedimentary rocks was accommodated in a series of half grabens and subsidiary full grabens situated within the Permo-Carboniferous Appalachian orogen. The Mesozoic ENAM is commonly depicted as a magma-rich continental rift margin, with magmatism (Central Atlantic magmatic province [CAMP]) driving continental breakup. However, the southern portion of the ENAM shows evidence of magmatic breakup (e.g., seaward-dipping reflectors), and rifting and crustal thinning appeared to start ~30 m.y. prior to CAMP emplacement in the Jurassic. This study provides extensive new detrital zircon and apatite U-Pb provenance data to determine the provenance and reconstruct the paleodrainages of the Newark Basin during progressive rifting and magmatic breakup and the implications for the overall rift configuration and asymmetry during progressive rifting along the ENAM rift margin. Detailed new detrital zircon (N = 21; n = 3093) and apatite (N = 4; n = 559) U-Pb results from sandstone outcrop and core samples from the Newark Basin indicate a distinct provenance shift, with relatively older Carnian syn-rift strata predominately sourced from the hanging wall of the basin bounding fault in the east while relatively younger Norian strata were regionally sourced from both the hanging wall and footwall. The syn-rift strata at the Triassic-Jurassic boundary were sourced from the hanging wall before a transition to local footwall terranes. These results suggest two major provenance changes during progressive rifting—the first occurring during Carnian crustal necking and rift flank uplift as predicted by recent numerical models and the second occurring at the onset of the Jurassic due to regional and local thermal uplift during CAMP magmatism as seen along other magma-rich margins, such as the North Atlantic and the southern portion of the South Atlantic margin.