Provenance History Research Articles

Design, Analysis and Experimental Testing of Composite Leaf Spring for Application in Electric Vehicle

In electric vehicle segment it is significantly observed that the excess weight of batteries (>10% of overall weight) reduces the travel range of electric vehicle. This excess weight of the batteries causes higher compression of the springs & also reduce the space available for suspension travel which reduces the life of suspension & comfort to the passenger. To overcome these issues, suspension needs to be reconfigured in terms of geometry & material of the suspension. Considering above changes in suspension system, Leaf Spring can be considered due to its proven history. Leaf spring has high load bearing capacity & can handle high loads at less deflection resulting in smoother ride. In this study glass fiber is used to analyze the application of leaf spring for excess weight in electric vehicle. The main objective of this study is to investigate feasibility of composite material for leaf spring to withstand the excess load in Electric vehicle. Rear leaf spring of TATA Sumo passenger vehicle is considered as case study model, which is semi-elliptical laminated type. The CAD model was created in CATIA & imported to ANSYS. Analytical, Experimental and Finite Element Analysis were carried out on composite prototype. Weight optimization of 67.70% for GFRP is observed in comparison to EN 46 material. For deflection 3.93%, for stiffness 4.06%, for energy absorbed 3.94% and for natural frequency is 5.25% difference is observed.

Jurassic sediments geochemical constraints on provenance, weathering process, and palaeoclimate variation of the north margin of Qaidam Basin, north‐eastern Tibetan Plateau

The Jurassic sequence in the northern Qaidam Basin can be represented by the lower coal‐bearing swamp‐lacustrine sediments unit and the upper reddish clastic deposits suite, which recorded dramatic transition of deposit environment changes. Whole‐rock geochemical data of this succession in Dameigou profile were used to reconstruct the provenance and chemical weathering history. Based on the major element discrimination diagrams, trace element ratios and chondritenormalized REE patterns, most sediments were derived from a similar source area with felsic‐intermediate rocks as dominant contributors. Multiple geochemical parameters and index displayed good correlation, via vertical variations sequence, Jurassic chemical weathering history of northern Qaidam Basin was established, and four stages were recognized from the profile. Phases I and III experienced intense chemical weathering, while Phases II and IV are characterized by mild to moderate chemical weathering. Based on this, long‐term Jurassic climatic evolution of the Qaidam Basin was reconstructed. Early‐middle period of Early Jurassic and middle period of Middle Jurassic developed warm and humid climate. On the contrary, late Early Jurassic‐early Middle Jurassic and late Middle Jurassic‐Late Jurassic was deposited under relatively semiarid to arid climatic conditions.

Combined detrital zircon fission track and U-Pb dating of the Late Paleozoic to Early Mesozoic sandstones in the Helanshan, western Ordos fold-thrust belt: Constraints for provenance and exhumation history

In order to unravel the Mesozoic sedimentation in response to multistage deformation of the western Ordos fold-thrust belt, combined zircon U-Pb and fission track analyses of single zircon grain are conducted for seven sandstone samples in the Helanshan area. Zircon FT ages are calculated using absolute uranium concentration determined by LA-ICP-MS during the procedure of zircon U-Pb dating. The newly-obtained zircon FT data show age features that are comparable with the previous zircon FT ages obtained by conventional FT methods (by which uranium contents are determined through an external detector to map induced fission tracks). The newly-obtained zircon FT ages have four subordinate FT age peaks (i.e., 225 Ma, 165 Ma, 125 Ma and 80 Ma) which are well matched with the regional geodynamic events occurred in the Late Triassic, Late Jurassic, Late Cretaceous and Early Cenozoic, respectively; and the zircon U-Pb ages have two main peaks at the Paleoproterozoic and the Late Paleozoic. The zircon U-Pb ages, integrating with the FT ages and available paleocurrents, suggest that the Paleoproterozoic basement rocks and Late Paleozoic plutonic rocks of the Alxa Block are the source rocks for the Triassic sandstones, and the Jurassic sandstones are associated with a multi-cycling sedimentation. The Jurassic sandstones contain recycled zircons that firstly deposited in the Triassic strata and subsequently exhumed during the Late Triassic-Early Jurassic.

Heavy mineral analysis of Eocene sands and sandstones of Nanka Formation, Cenozoic Niger Delta petroleum province

ABSTRACT The heavy minerals present in lithologic sand and sandstone units of Nanka Formation are mainly zircon, rutile, tourmaline, apatite, staurolite, and opaque minerals (Goethite, hematite, ilmenite), which are present dominant in weathered sandstones when analysed using petrographic varietal studies to infer provenance, diagenesis and source area weathering history. The low-diversity and relative abundance of heavy mineral assemblages are controlled by provenance and diagenetic processes, and these present limitations in accurate reconstruction of the paleo-history of these lithologic units using heavy minerals analysis alone. These lithologic Eocene units are derived from intensely weathered granitic and metamorphic source rocks and they are composed dominantly of matured polycyclic sediments.

Provenance and depositional history of Mesozoic sediments from the Mamfe basin and Douala sub-basin (SW Cameroon) unraveled by geochemical analysis

Mineralogical and geochemical analytical methods were employed to characterize sediment samples from the Mamfe basin (MB) and Douala sub-basin (DSB) in order to constrain the provenance, weathering, paleoclimate, and depositional history of rocks from both basins. Sediments under study are classified as shales, wackes, and arkoses and are essentially derived from felsic rocks which likely correspond to nearby extensive Neoproterozoic migmatitic and gneissic basement rocks. The A-CN-K plot indicates that the K-metasomatism may have affected the bulk composition of most of the studied rocks. The Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA), and (A-K)-C-N plots suggest that the intensity of weathering was higher for DSB relative to MB samples. This differentiation can be related to active tectonism during the deposition of the MB sediments. The SiO2/Al2O3, Al2O3/Na2O, and K2O/Na2O ratios, and the Index of Chemical Variability (ICV), indicate a low compositional maturity for MB compared with DSB samples. The values of U/Th, V/Cr, Ni/Co, and authigenic U suggest an oxic depositional condition for all studied samples. The average Sr/Ba ratios for the MB (0.31 ± 0.12 and 0.59 ± 0.25, for the Okoyong and Nfaitok-Yawo areas, respectively) and DSB sediments (0.31 ± 0.08 and 0.20 ± 0.09, for southern Kumba and western Mbanga areas, respectively), suggest a depositional paleoenvironment with low salinity. The average Rb/Sr ratios for the MB (0.62 ± 0.36 and 0.17 ± 0.06, for the Okoyong and Nfaitok-Yawo areas, respectively) and DSB sediments (0.53 ± 0.11 and 0.73 ± 0.29, for southern Kumba and western Mbanga areas, respectively) are low, suggesting warm and humid condition during the deposition of MB and DSB sediments. Multi-element tectonic diagrams indicate passive and rift settings, which are consistent with the local geology, but also a collisional setting, which is probably linked to the tectonic evolution of the Neoproterozoic metamorphic source rocks.

Magnetic polarity stratigraphy, provenance, and paleoclimate analysis of Cenozoic strata in the Qaidam Basin, NE Tibetan Plateau

AbstractThe growth and deformation history of the Qilian-Nan Shan thrust belt bounding the NE Qaidam Basin figures importantly in testing models of Tibetan Plateau uplift during the India-Asia collision. However, debate exists about the onset of uplift and exhumation of the Qilian-Nan Shan, with timing estimates ranging from early Paleocene to late Miocene. Here we report integrated analyses of magnetostratigraphy, anisotropy of magnetic susceptibility, sediment provenance, and paleoclimate (using environmental magnetic parameters) for Cenozoic fluvio-lacustrine strata from the Dahonggou section south of the Qilian-Nan Shan. The results are interpreted to demonstrate an early Miocene (ca. 20 Ma) onset of sediment accumulation in this location, with clastic sediment derived initially from the southern Qimen Tagh highland. The sediment source then switched to the northern part of the Qilian Shan region after ca. 18.5 Ma, consistent with initial uplift and exhumation of the Qilian Shan. Thereafter, two additional provenance shifts reveal progressive southward propagation of deformation in the Qilian-Nan Shan. As a result of this southward growth of Qilian-Nan Shan topography, precipitation increased after ca. 11 Ma at the study site due to orographic interception of moisture from the south. This work improves our understanding of the depositional age, sediment provenance, and paleoclimate history of the Qaidam Basin and reveals a prolonged history of Qilian-Nan Shan deformation and uplift, which may have accelerated during the late Miocene.

Risk Factors Associated With Medial Tibial Stress Syndrome In Military Cadets During Basic Training

Medial Tibial Stress Syndrome (MTSS) is one of the most frequent pathologies in military personnel. As the muscles of the lower extremity contribute to the attenuation of impact forces in activities such as running and jumping, neuromuscular performance deficiencies and asymmetries may be associated with an increased risk for musculoskeletal injuries. PURPOSE: To determine the kinetic risk factors associated with MTSS through the bilateral countermovement jump (CMJ) in army cadets. METHODS: Ethical approval was granted by the General José María Córdova Military School of Cadets where the study was conducted. This observational study was executed in a cohort of 123 cadets (followed for 24 weeks) who entered to the military school in 2017. Anthropometric, demographic data and MTSS history were recorded. Jump height (cm), peak landing force (N*kg), peak landing force asymmetry (%), concentric mean force (N*kg), concentric mean force asymmetry (%), eccentric deceleration rate of force development (EDRFD [N/s*Kg]) and EDRFD asymmetry (%) were evaluated through the bilateral CMJ on a pair of uniaxial force platforms. After the follow-up, the cadets with MTSS were determined through the clinical history. RESULTS: The incidence of MTSS was 13% (n= 16). In the bivariate analysis, height, EDRFD asymmetry, sex (female; RR= 2.84; 95% CI = 1.16-6.94), provenance (rural; RR= 2.65; 95% CI= 1.04-6.72), and MTSS history (yes; RR= 5.71; 95% CI= 2.23-14.62), were significantly associated with MTSS (p≤0.05). In the logistic regression, EDRFD asymmetry (OR= 1.03; 95% CI= 1.00-1.07), sex (OR= 4.91; 95% CI = 1.38-13.37), and provenance (OR= 4.82; 95% CI = 1.04-6.72), were significantly associated with MTSS (p≤0.05). MTSS history was significant for p≤0.1 (OR= 8.95; 95% CI= 0.68-118.73). The predictive model was significantly associated with MTSS (p≤0.01), had a sensitivity of 31.3% and a specificity of 99.1% (overall prognosis of 90.2%). CONCLUSIONS: While we identified important non-modifiable risk factors for MTSS in cadets during basic training, we also found that higher CMJ EDRFD asymmetry was a significant risk factor. This suggests that the bilateral CMJ may be a useful tool for pre-entry screening in and that high EDRFD asymmetry could be a potential target of pre-basic training risk reduction conditioning.

Petrological and geochemical compositions of beach sands of the Barton and Weaver peninsulas of King George Island, West Antarctica: implications for provenance and depositional history

Petrological and geochemical compositions of beach sands of the Barton and Weaver peninsulas of King George Island, West Antarctica: implications for provenance and depositional history

Tectonic and sediment provenance evolution of the South Eastern Pyrenean foreland basins during rift margin inversion and orogenic uplift

The Cretaceous to Oligocene detrital record in the southern Eastern Pyrenees is utilized to address the degree to which precursor basin architecture and hyper-extensional rift structures impacted subsequent sedimentary provenance and dispersal systems and foreland basin evolution. This study presents new isotopic provenance analysis of detrital zircon UPb and (UTh)/He double-dating, and detrital rutile UPb and trace element geochemistry to track sediment provenance evolution. Late Cretaceous-Paleocene sediments show zircon with dominantly Variscan UPb and Jurassic-Early Cretaceous ZHe cooling ages that are derived from southeastern Catalan Coastal Ranges and eastern Corsica-Sardinia regions, and localized structural inversion along inherited Mesozoic extensional faults and erosional recycling of syn-rift sediments. Eocene deposits have multimodal UPb ages that stratigraphically upsection change to unimodal Variscan ages, with the appearance and upsection increase in Pyrenean ZHe ages, and increase in Variscan aged detrital rutile that record a significant shift in sediment source area to northern sources recording exhumation and unroofing of the Axial Zone Paleozoic basement sources, and development of new ramp-flat style structures in the Southern Pyrenean Zone fold-thrust belt. During the Oligocene, incipient foreland basin deposits were cannibalized and recycled into the foreland basin as thrusting advanced toward the foreland. The Eastern Pyrenean foreland basin records a different provenance history from Central Pyrenean Tremp Basin, suggesting the basins were segmented throughout the Late Cretaceous to Oligocene, while the Ripoll and Ager basins appear to have shared similar source areas. The sediment provenance evolution coupled with Pyrenean fault activity and shortening rates, hinterland exhumation, foreland basin subsidence, and climate proxies presents a detailed dataset to understand these relationships within the Eastern Pyrenean orogenic system and highlight the dominant control precursor basins and structural inheritance has on the subsequent fold-thrust belts and foreland basin evolution.

Lipid Profiles in Lyme Borreliosis: A Potential Role for Apheresis?

Dyslipidemia and dyslipoproteinemia are common causes of metabolic and cardiovascular diseases. On the other hand, intracellular bacteria, such as Borrelia burgdorferi, utilize host lipids to survive and disseminate within the host. Recent data suggest that elevated lipids are a contributing factor to the maintenance and severity of Lyme disease and its complications. Here we review and discuss the role of lipids in Borreliosis and report on a pilot trial to examine the potential roles of circulating lipids and lipoproteins in patients with Borrelia infection. In this analysis we assessed the clinical and lipid profiles of 519 patients (319 women, 200 men) with a proven history of Lyme disease, before and after an extracorporeal double membrane filtration. Lipid profiles pre- and post-apheresis were analyzed in conjunction with clinical symptoms and parameters of inflammation. Circulating cholesterol, triglycerides, LDL, LP(a), and other inflammatory lipids were significantly reduced after the apheresis, while symptoms of the disorder and bioindexes of inflammation such as CRP improved. Further studies should be initiated to investigate the possibly causal relation between Lyme disease and circulating lipids and to design appropriate therapeutic strategies.

ORION—Art Collections and Collectors in Portugal

ORION is a digital art history research-oriented project focused on the study of art collections and collectors in Portugal, supported on a relational database management system. Besides the obvious advantage of organizing and systematizing an enormous amount of information, promoting its analysis, this database was specifically designed to highlight the relationships between data. Its relational capacity is not only one of the most relevant features of ORION, but a differentiating quality, one step forward in comparison to other international databases and studies that use digital methodologies. This article discusses the methods and the advantages of using ORION in research related to the history of collecting, art markets and provenance of art objects in Portugal, where it is the very first time that an approach such as this is intended, looking for a systematization of data that paves the way to the emergence of new research questions. Furthermore, and because ORION aims to share the data and knowledge with other projects, institutions and researchers, the database uses different international standards, such as data structure (CIDOC-OIC and Getty-CDWA), controlled vocabulary (Iconclass, Art and Architecture Thesaurus (AAT), Thesaurus of Geographic Names (TGN), and Union List of Artist Names (ULAN)) and communication and exchange of information (CIDOC-CRM).

Combining multiple methods for provenance discrimination based on rare earth element geochemistry in lake sediment

Geochemical properties of rare earth elements (REEs) have the potential to represent the provenance and depositional history of surface sediment in aquatic environments. In this study, both surface and core sediment samples were collected from Dongting Lake to investigate the distribution characteristics and source of REEs by combining the methodologies of geostatistics, positive matrix factorization (PMF) model, discriminant function (DF), and provenance index (PI) based on REEs geochemical parameters. The results indicated that the total REEs content in sediment samples ranged from 129.12 to 284.02 μg g−1, with the average REEs content calculated to be 197.95 μg g−1. Light REEs (LREEs) comprised >90% of the total REEs, indicating that there was an enrichment of LREEs in the sediment samples. The REEs of the surface sediment showed strong spatial variation, with relatively high values located in Eastern Dongting Lake and relatively lower levels in Western Dongting Lake. Moreover, the vertical distributions of ∑REEs, ∑LREEs and ∑HREEs at most sampling sites behaved similarly with rapid increase until about 6–8 cm, followed by a downward trend with some irregularities. The strong association between most REEs confirmed that they often have a positive correlation and co-existence in sediment. The PMF model revealed that most of the REEs in the surface sediment were derived from natural sources with some anthropogenic inputs also serving as contributing sources. The DF and PI results indicated that the REEs distribution pattern in the surface sediment of Dongting Lake was similar to that of the Yangtze River, suggesting that Yangtze River had been more of an influence on sediment loads than the upstream tributaries. This study highlights the broader applicability of the REEs tracing method in sediment transport processes and can provide new knowledge regarding source apportionment analysis of sediment-related contaminants in aquatic environments.

Blockchain analytics and artificial intelligence

Blockchain records track information about financial payments, movements of products through supply chains, identity verification information, and many other assets. Analytics on this data can provide provenance histories, predictive planning, fraud identification, and regulatory compliance. In this paper, we describe analytics engines connected to blockchains to provide easy-to-use configurable dashboards, predictive models, provenance histories, and compliance checking. We also describe how blockchain data can be combined with external data sources for secure and private analytics, enable artificial intelligence (AI) model creation over geographically dispersed data, and create a history of model creation enabling provenance and lineage tracking for trusted AI.

Improving the precision of single grain mica 40Ar/39Ar-dating on smaller and younger muscovite grains: Application to provenance studies

Current generation multi-collector mass spectrometers allow for increasingly more precise measurements of small ion beams. The improvement of instrument sensitivity and resolution compared with older generation mass spectrometers has important implications for 40Ar/39Ar dating and allows the expanding of its range of applicability.Thermochronological analysis of detrital modern river sands is a powerful tool for unraveling provenance and exhumation histories of eroding hinterlands. Better instrument sensitivity allows refining the precision of dates for young and small grains, which in turn acknowledge an interpretation of the detrital signals from a wider range of micas. Previous studies have used the 40Ar/39Ar method to assess how the detrital mineral age signals can evolve downstream in the river trunk of an active mountain range. So far, however, there has not been a robust assessment of how grain-size variability can introduce biases in the analysis of age distributions. For example, the white mica signal from the Namche Barwa syntaxis in the eastern Himalaya is interpreted to be diluted downstream from its source due to the admixture of micas from downstream sources to the total population, but grain-size variability biases were not evaluated. Here we use the latest developments in multi-collector noble gas mass spectrometry to (1) test if the precision in the analysis of young and small muscovite samples can be improved by use of new faraday collector amplifier technology and (2) to apply this approach to test the variability of the age distribution as a function of the grain size from five modern rivers samples draining the Eastern Himalaya.The Helix MC plus at VUA is equipped with 1013 Ohm amplifiers on the H2-H1 Faraday cups. We compare the functioning of the 1013 Ohm amplifiers with the 1012 amplifiers on the in-house Drachenfels (DRA) standard. The use of the new 1013 Ohm amplifiers to measure the 40Ar and 39Ar ion beams improved the precision when measuring standards by a factor of two.We show that for larger catchment areas multi grain-size analyses lead to a more complete assessment of the full spectrum of ages obtained from different sources. The analyses of smaller grain sizes (< 250 μm) show that previous ideas/arguments about the process of dilution of the Namche Barwa syntaxis age signal for muscovite were biased due to the measurement of exclusively larger grain-sizes (> 250 μm) of the analyzed samples. This outcome potentially has important implications for future provenance studies.

Recrystallization and Provenance History of the Upper Kaimur Group Siliciclastics, Son Valley, India: Coupled Petrographic and Fluid inclusion Proxy

Abstract The Mesoproterozoic Kaimur Group belonging to upper part of Vindhyan Supergroup, conformably overlies the carbonate sequence of Semri Group (Lower Vindhyan) in the Son Valley, central India. The Upper Kaimur Group consists of Dhandraul sandstone, Scarp sandstone and Bijaigarh shale. The detrital contents of the Dhandraul and Scarp sandstones are mainly composed of several varieties of quartz followed by feldspar, rock fragments, micas and heavy minerals. Fluid inclusion studies are carried out on the detrital and recrystallized quartz grains of the Dhandraul and Scarp sandstone to know about the fluid phases already present in the source rock and / or introduced in the recrystallisation process. Fluid micro-thermometry reveals the presence of two types of fluids: (i) bi-phase low saline aqueous inclusions, (ii) bi-phase high saline aqueous inclusion. These fluids were trapped during the development of grain and recrystallization processes. The salinity of these inclusions in the quartz grain is in the range of 5.7 to 13.4% suggests that initially there was good proportion of marine water during the initiation of sedimentation. The provenance of these rocks may be granite/metamorphic rocks of Mahakoshal Group and Chhotanagpur granite-gneisses and minor input from Bundelkhand granite complex.

Detrital graphite particles in the Cryogenian Nantuo Formation of South China: Implications for sedimentary provenance and tectonic history

The tectonic history of the Yangtze block of South China prior to the Ediacaran Period has been a matter of debate. In particular, the tectonic history of the Shennongjia terrane in the central-northern margin of the Yangtze block is poorly understood, and the tectonic relationship between the Shennongjia terrane and the Huangling massif (exposed in the Huangling anticline) is unclear. Previous researchers have reported U-Pb dates of detrital zircons and Nd isotopic compositions of clastic rocks from Cryogenian successions in the Shennongjia terrane to identify ancient crustal remnants and the provenance of clastic sediments, and to constrain the age and crustal evolution of the Yangtze block. Here, we describe abundant graphite discs from silty mudstone of the Cryogenian Nantuo Formation in the Shennongjia area of the Yangtze block. These graphite discs are opaque, ∼23–171 μm in size, and highly reflective. Most are abraded or rounded, although some show hexagonal crystalline morphology. Their Raman spectra are distinct from those of indigenous carbonaceous material (CM) in the sedimentary matrix from the Nantuo Formation at the same locality. Raman CM geothermometric analysis indicates that graphite discs experienced a maximum metamorphic temperature of nearly 600 °C, which is inconsistent with the relatively low metamorphic grade of the host rock. These observations indicate that the graphite discs are of detrital origin, most likely derived from high-grade metamorphic rocks in the basement of the Yangtze block (e.g., the Archean-Paleoproterozoic Kongling terrain in the core of the Huangling anticline), consistent with the hypothesis that the Shennongjia region was a part of Yangtze block by the end of the Cryogenian Period.

SOCCOMAS: a FAIR web content management system that uses knowledge graphs and that is based on semantic programming.

We introduce Semantic Ontology-Controlled application for web Content Management Systems (SOCCOMAS), a development framework for FAIR (‘findable’, ‘accessible’, ‘interoperable’, ‘reusable’) Semantic Web Content Management Systems (S-WCMSs). Each S-WCMS run by SOCCOMAS has its contents managed through a corresponding knowledge base that stores all data and metadata in the form of semantic knowledge graphs in a Jena tuple store. Automated procedures track provenance, user contributions and detailed change history. Each S-WCMS is accessible via both a graphical user interface (GUI), utilizing the JavaScript framework AngularJS, and a SPARQL endpoint. As a consequence, all data and metadata are maximally findable, accessible, interoperable and reusable and comply with the FAIR Guiding Principles. The source code of SOCCOMAS is written using the Semantic Programming Ontology (SPrO). SPrO consists of commands, attributes and variables, with which one can describe an S-WCMS. We used SPrO to describe all the features and workflows typically required by any S-WCMS and documented these descriptions in a SOCCOMAS source code ontology (SC-Basic). SC-Basic specifies a set of default features, such as provenance tracking and publication life cycle with versioning, which will be available in all S-WCMS run by SOCCOMAS. All features and workflows specific to a particular S-WCMS, however, must be described within an instance source code ontology (INST-SCO), defining, e.g. the function and composition of the GUI, with all its user interactions, the underlying data schemes and representations and all its workflow processes. The combination of descriptions in SC-Basic and a given INST-SCO specify the behavior of an S-WCMS. SOCCOMAS controls this S-WCMS through the Java-based middleware that accompanies SPrO, which functions as an interpreter. Because of the ontology-controlled design, SOCCOMAS allows easy customization with a minimum of technical programming background required, thereby seamlessly integrating conventional web page technologies with semantic web technologies. SOCCOMAS and the Java Interpreter are available from (https://github.com/SemanticProgramming).

Multicentre, open-label, randomised controlled clinical trial to assess the efficacy and safety of appropriate target values for lipid management in patients who have mild-to-moderate stenotic lesions with high-risk plaques in coronary arteries: study protocol

IntroductionTo detect patients at high risk of developing myocardial infarction, plaque characteristics as well as the degree of stenosis in coronary arteries should be evaluated. However, unstable plaque or severe...

U[sbnd]Pb and Sm[sbnd]Nd constraints on miocene units in the Ischigualasto-Villa Unión foreland basin, Sierras Pampeanas, Argentina: Sedimentary provenance, landscape evolution coupling flat-slab subduction

Foreland basin systems are intimately linked to thrust belts and activation and reactivation of structures in association with convergent plate dynamics, capable of controlling regional uplifts, sedimentation, as well as drainage patterns among other processes. The Ischigualasto-Villa Unión basin (IVB) is a Miocene broken foreland, occurring in-between the Famatina-Sañogasta, Valle Fértil and Maz Ranges in the Western Sierras Pampeanas, Argentina, Central Andes. We conducted U–Pb geochronology by SHRIMP in igneous zircons and LA-ICPMS in detrital zircons as well as whole rock Sm–Nd analyses in the Quebrada del Médano and Desencuentro Formations – the uppermost units of the IVB. The new and compiled data provide new insights on the influence of flat-slab on the uplift of the Sierras Pampeanas and Precordillera and consequent shift of the drainage patterns in the basin infill. The SHRIMP age for the youngest zircons from a volcanic tuff of the middle portion of the Desencuentro Formation yielded a mean 206Pb/238U age of 8.49 ± 0.33 Ma whereas the other grains gave concordant ages from 10 to 1433 Ma. The detrital zircon ages from both Formations indicated that different sourced materials contributed to the basin infill, through time and space. The major age modes in the detrital populations were: 1) 1250-950 Ma, (2) 850-600 Ma, (3) 540-500 Ma, (4) 490-460 Ma, (5) 350-320 Ma, (6) 300-250, (7) 40 Ma and (8) 16-8 Ma. From a statistical point of view, we defined two similar aged groups with distinct major contribution provenance: a first cluster with main Cambrian-Ordovician ages and a second one with main Permian and Mesoproterozoic ages. The bulk picture suggests a critical change in the IVB provenance history since the mid-late Miocene, roughly consistent with the Pampean flat-slab subduction model that controls uplifts of the Western and Eastern Sierras Pampeanas and associated regional drainage shifts in Central Andes, as like geodynamic processes in Western North America. We interpret the statistic change in the distribution of the IVB zircons as product of: (1) the presence of axial rivers flowing parallel to the basement arches in the more distal foreland; (2) a disconnection between the IVB and the Bermejo basin related to the uplift of the IVB western margin; (3) the uprising of the IVB eastern ranges. Our findings are also consistent with the acquired TDM ages (1.2–0.9 Ga) and the coupled εNd(t) constraints (−6 to −5) for samples collected along the stratigraphy of both IVB Formations that indicated recycled Grenville-aged sources were likely overload by sourced rocks with high lithologic erodibility.

Occurrence and diversity of cyanotoxins in Greek lakes

Toxic cyanobacteria occur in Greek surface water bodies. However, studies on the occurrence of cyanotoxins (CTs) are often limited to mainly microcystins (MCs), with use of screening methods, such as ELISA, that are not conclusive of the chemical structure of the CT variants and can be subject to false positive results. A multi-lake survey in Greece (14 lakes) was conducted in water and biomass, targeted to a wide range of multi-class CTs including MCs, nodularin-R (NOD), cylindrospermopsin (CYN), anatoxin-a (ANA-a) and saxitoxins (STXs), using multi-class/variant LC-MS/MS analytical workflows, achieving sensitive detection, definitive identification and accurate quantitation. A wide variety of CTs (CYN, ANA-a, STX, neoSTX, dmMC-RR, MC-RR, MC-YR, MC-HtyR, dm3MC-LR, MC-LR, MC-HilR, MC-WR, MC-LA, MC-LY, MC-LW and MC-LF), were detected, with MCs being the most commonly occurring. In biomass, MC-RR was the most abundant toxin, reaching 754 ng mg−1 dw, followed by MC-LR (458 ng mg−1 dw). CYN and ANA-a were detected for the first time in the biomass of Greek lakes at low concentrations and STXs in lakes Trichonis, Vistonis and Petron. The abundance and diversity of CTs were also evaluated in relation to recreational health risks, in a case study with a proven history of MCs (Lake Kastoria).