scholarly journals The role of slab geometry in the exhumation of cordilleran-type orogens and their forelands: Insights from northern Patagonia

Author(s):  
Marie C. Genge ◽  
Massimiliano Zattin ◽  
Elisa Savignano ◽  
Marta Franchini ◽  
Cécile Gautheron ◽  
...  

In cordilleran-type orogens, subduction geometry exerts a fundamental control on the tectonic behavior of the overriding plate. An integrated low-temperature, large thermochronological data set is used in this study to investigate the burial and exhumation history of the overriding plate in northern Patagonia (40°−45°S). Thermal inverse modeling allowed us to establish that a ∼2.5−4-km-thick section originally overlaid the Jurassic−Lower Cretaceous successions deposited in half-graben systems that are presently exposed in the foreland. Removal of the sedimentary cover started in the late Early Cretaceous. This was coeval with an increase of the convergence rate and a switch to a westward absolute motion of the South American Plate that was accompanied by shallowing of the subducting slab. Unroofing was probably further enhanced by Late Cretaceous to early Paleogene opening of a slab window beneath the overriding plate. Following a tectonically quiescent period, renewed exhumation occurred in the orogen during relatively fast Neogene plate convergence. However, even the highly sensitive apatite (U-Th)/He thermochronometer does not record any coeval cooling in the foreland. The comparison between Late Cretaceous and Neogene exhumation patterns provides clear evidence of the fundamental role played by inter-plate coupling associated with shallow slab configurations in controlling plate-scale deformation. Our results, besides highlighting for the first time how the whole northern Patagonia foreland was affected by an exhumation of several kilometers since the Late Cretaceous, provide unrivalled evidence of the link between deep geodynamic processes affecting the slab and the modes and timing of unroofing of different sectors of the overriding plate.

Author(s):  
V. V. Sapyanik ◽  
◽  
E. Yu. Lapteva ◽  
E. V. Lyubutina ◽  
A. I. Nedospasov ◽  
...  

The article deals with geodynamic processes of the plicative tectonics of the Mesozoic-Cenozoic development stage in the southeastern territory of the West Siberian hemisyneclise, which allowed scientists to significantly clarify the configuration of multi-ordinal structures, to identify the second-order negative structure in the territory of the Baraba-Pikhtovka monocline, and to offer a new view of the structural-tectonic zoning of the Tomsk region eastern territory sedimentary cover. To substantiate the prospects of Jurassic petroleum plays, their resource potential is estimated using the basin modeling method. Based on an integrated analysis of structural imagings, history of the territory tectonic development, calculated maps of effective capacities, test results and WL conclusions, 42 traps of structural, structural-lithological, structural-stratigraphic types were mapped and their assessment by the volume-statistic method by Dl category [inferred resources] was given. The results obtained significantly expand the prospects for peripheral territories of the West Siberian Plate, where it is necessary to complete regional geological exploration.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2075 ◽  
Author(s):  
Pedro L. Godoy ◽  
Mario Bronzati ◽  
Estevan Eltink ◽  
Júlio C. de A. Marsola ◽  
Giovanne M. Cidade ◽  
...  

The postcranial anatomy of Crocodyliformes has historically been neglected, as most descriptions are based solely on skulls. Yet, the significance of the postcranium in crocodyliforms evolution is reflected in the great lifestyle diversity exhibited by the group, with members ranging from terrestrial animals to semi-aquatic and fully marine forms. Recently, studies have emphasized the importance of the postcranium. Following this trend, here we present a detailed description of the postcranial elements ofPissarrachampsa sera(Mesoeucrocodylia, Baurusuchidae), from the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). The preserved elements include dorsal vertebrae, partial forelimb, pelvic girdle, and hindlimbs. Comparisons with the postcranial anatomy of baurusuchids and other crocodyliforms, together with body-size and mass estimates, lead to a better understanding of the paleobiology ofPissarrachampsa sera, including its terrestrial lifestyle and its role as a top predator. Furthermore, the complete absence of osteoderms inP. sera, a condition previously known only in marine crocodyliforms, suggests osteoderms very likely played a minor role in locomotion of baurusuchids, unlike other groups of terrestrial crocodyliforms. Finally, a phylogenetic analysis including the newly recognized postcranial features was carried out, and exploratory analyses were performed to investigate the influence of both cranial and postcranial characters in the phylogeny of Crocodyliformes. Our results suggest that crocodyliform relationships are mainly determined by cranial characters. However, this seems to be a consequence of the great number of missing entries in the data set with only postcranial characters and not of the lack of potential (or synapomorphies) for this kind of data to reflect the evolutionary history of Crocodyliformes.


2020 ◽  
Vol 21 (2) ◽  
pp. 143-148
Author(s):  
Michael W. Overton

AbstractBovine respiratory disease (BRD) is a frequent disease concern in dairy cattle and is most commonly diagnosed in young dairy heifers. The impact of BRD is highly variable, depending on the accuracy and completeness of detection, effectiveness of treatment, and on-farm culling practices. Consequences include decreased rate of weight gain, a higher culling risk either as heifers or as cows, delayed age at first service, delayed age at first calving, and in some cases, lower future milk production. In this data set of 104,100 dairy replacement heifers from across the USA, 36.6% had one or more cases diagnosed within the first 120 days of age with the highest risk of new cases occurring prior to weaning. Comparison of the raising cost for heifers with BRD and those without a recorded history of BRD resulted in an estimated cost per incident case occurring in the first 120 days of age of $252 or $282, depending upon whether anticipated future milk production differences were considered or not. Current market conditions contributed to a cost estimate that is significantly higher than previously published estimates, driven in part by the losses associated with selective culling of a subset of heifers that experienced BRD.


Author(s):  
Charles D. Phillips ◽  
Kathleen M. Spry

RÉSUMÉTrès peu de recherches ont été effectuées sur les pensionnaires des maisons de soins ayant manifestés des troubles mentaux chroniques sans démence avant leur entrée en institution. Les données du Minimum Data Set for Nursing Home Resident Assessment and Care Screening (MDS) de 1993 ont été utilisées pouranalyser les différences dans les caractéristiques et les soins se rapportant à ce type de pensionnaires par rapport aux autres pensionnaires. Cette enquête portait sur 70 000 pensionnaires du Kansas, du Maine, du Mississippi et du Dakota du Sud. Les caractéristiques des pensionnaires qui éprouvaient ce type de troubles mentaux chroniques étaient plus fréquemment les suivantes: sexe masculin, 65 ans et plus, bénéficiaires de Medicaid, moins médicalement inaptes et niveau plus élevé de problèmes de comportements. Ces pensionnaires reçoivent aussi davantage de médicaments psychotropes et suivant une thérapie, la prévalence de la thérapie étant cependant moins éleveé. Les informations recueillies pourraient laisser croire que les soins accordés à ces pensionnaires ne sont pas des plus appropriés.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Fan Li ◽  
Yunyun Lv ◽  
Zhengyong Wen ◽  
Chao Bian ◽  
Xinhui Zhang ◽  
...  

Abstract Background Although almost all extant spider species live in terrestrial environments, a few species live fully submerged in freshwater or seawater. The intertidal spiders (genus Desis) built silk nests within coral crevices can survive submerged in high tides. The diving bell spider, Argyroneta aquatica, resides in a similar dynamic environment but exclusively in freshwater. Given the pivotal role played by mitochondria in supplying most energy for physiological activity via oxidative phosphorylation and the environment, herein we sequenced the complete mitogenome of Desis jiaxiangi to investigate the adaptive evolution of the aquatic spider mitogenomes and the evolution of spiders. Results We assembled a complete mitogenome of the intertidal spider Desis jiaxiangi and performed comparative mitochondrial analyses of data set comprising of Desis jiaxiangi and other 45 previously published spider mitogenome sequences, including that of Argyroneta aquatica. We found a unique transposition of trnL2 and trnN genes in Desis jiaxiangi. Our robust phylogenetic topology clearly deciphered the evolutionary relationships between Desis jiaxiangi and Argyroneta aquatica as well as other spiders. We dated the divergence of Desis jiaxiangi and Argyroneta aquatica to the late Cretaceous at ~ 98 Ma. Our selection analyses detected a positive selection signal in the nd4 gene of the aquatic branch comprising both Desis jiaxiangi and Argyroneta aquatica. Surprisingly, Pirata subpiraticus, Hypochilus thorelli, and Argyroneta aquatica each had a higher Ka/Ks value in the 13 PCGs dataset among 46 taxa with complete mitogenomes, and these three species also showed positive selection signal in the nd6 gene. Conclusions Our finding of the unique transposition of trnL2 and trnN genes indicates that these genes may have experienced rearrangements in the history of intertidal spider evolution. The positive selection signals in the nd4 and nd6 genes might enable a better understanding of the spider metabolic adaptations in relation to different environments. Our construction of a novel mitogenome for the intertidal spider thus sheds light on the evolutionary history of spiders and their mitogenomes.


2021 ◽  

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.


2021 ◽  
pp. SP495-2021-72
Author(s):  
Domenico Chiarella ◽  
Daniel Joel

AbstractDeep-marine gravity-driven deposits represent one of the more investigated depositional systems due to their potential interest as target for exploration and carbon capture and storage activities, as well as an important record of the depositional history of a basin through time. Although the Halten Terrace (Norwegian Sea) is one of the main successful exploration areas, we still have poor understanding of the post-rift Cretaceous interval. Here, 3D seismic reflection and borehole data are integrated to investigate the stratigraphic distribution and sedimentological characteristics of the Cenomanian-Turonian intra Lange Sandstones in the Gimsan Basin and Grinda Graben. The Lange Formation records the deposition in a deep-marine environment of a thousand meter thick shale unit punctuated by tens of meters thick gravity-driven coarse-grained sandstone intervals sourced from the Norwegian mainland. The presence of gravity-driven deposits and the deep-marine setting is supported by seismic interpretation, architectural elements and the facies analysis of cored material acquired within the studied stratigraphic interval. Borehole data indicate the presence of both turbidites and hybrid-event beds rich in mud content. The results of this study have implications for the understanding of the distribution and reservoir potentiality of the Late Cretaceous Lange Formation in the Halten Terrace.


Author(s):  
Sara Fuentes-Soriano ◽  
Elizabeth A. Kellogg

Physarieae is a small tribe of herbaceous annual and woody perennial mustards that are mostly endemic to North America, with its members including a large amount of variation in floral, fruit, and chromosomal variation. Building on a previous study of Physarieae based on morphology and ndhF plastid DNA, we reconstructed the evolutionary history of the tribe using new sequence data from two nuclear markers, and compared the new topologies against previously published cpDNA-based phylogenetic hypotheses. The novel analyses included ca. 420 new sequences of ITS and LUMINIDEPENDENS (LD) markers for 39 and 47 species, respectively, with sampling accounting for all seven genera of Physarieae, including nomenclatural type species, and 11 outgroup taxa. Maximum parsimony, maximum likelihood, and Bayesian analyses showed that these additional markers were largely consistent with the previous ndhF data that supported the monophyly of Physarieae and resolved two major clades within the tribe, i.e., DDNLS (Dithyrea, Dimorphocarpa, Nerisyrenia, Lyrocarpa, and Synthlipsis)and PP (Paysonia and Physaria). New analyses also increased internal resolution for some closely related species and lineages within both clades. The monophyly of Dithyrea and the sister relationship of Paysonia to Physaria was consistent in all trees, with the sister relationship of Nerisyrenia to Lyrocarpa supported by ndhF and ITS, and the positions of Dimorphocarpa and Synthlipsis shifted within the DDNLS Clade depending on the employed data set. Finally, using the strong, new phylogenetic framework of combined cpDNA + nDNA data, we discussed standing hypotheses of trichome evolution in the tribe suggested by ndhF.


2021 ◽  
pp. emermed-2020-210412
Author(s):  
Richard Hotham ◽  
Colin O'Keeffe ◽  
Tony Stone ◽  
Suzanne M Mason ◽  
Christopher Burton

BackgroundEDs globally are under increasing pressure through rising demand. Frequent attenders are known to have complex health needs and use a disproportionate amount of resources. We hypothesised that heterogeneity of patients’ reason for attendance would be associated with multimorbidity and increasing age, and predict future attendance.MethodWe analysed an anonymised dataset of all ED visits over the course of 2014 in Yorkshire, UK. We identified 15 986 patients who had five or more ED encounters at any ED in the calendar year. Presenting complaint was categorised into one of 14 categories based on the Emergency Care Data Set (ECDS). We calculated measures of heterogeneity (count of ECDs categories and entropy of categories) and examined their relationship to total number of ED visits and to patient characteristics. We examined the predictive value of these and other features on future attendance.ResultsMost frequent attenders had more than one presenting complaint type. Heterogeneity increased with number of attendances, but heterogeneity adjusted for number of attendances did not vary substantially with age or sex. Heterogeneity was associated with the presence of one or more contacts for a mental health problem. For a given number of attendances, prior mental health contact but not heterogeneity was associated with further attendance.ConclusionsHeterogeneity of presenting complaint can be quantified and analysed for ED use: it is increased where there is a history of mental disorder but not with age. This suggests it reflects more than the number of medical conditions.


2018 ◽  
Vol 46 (1) ◽  
pp. 3-24 ◽  
Author(s):  
Ori Swed ◽  
Jae Kwon ◽  
Bryan Feldscher ◽  
Thomas Crosbie

From an obscure sector synonymous with mercenaryism, the private military and security industry has grown to become a significant complementing instrument in military operations. This rise has brought with it a considerable attention. Researchers have examined the role of private military and security companies in international relations as well as the history of these companies, and, above all, the legal implications of their use in the place of military organizations. As research progresses, a significant gap has become clear. Only a handful of studies have addressed the complex of issues associated with contractors’ demographics and lived experience. This article sheds some light over this lacuna, examining contractors’ demographics using descriptive statistics from an original data set of American and British contractors who died in Iraq between the years 2003 and 2016. The article augments our understanding of an important population of post-Fordist-contracted workforce, those peripheral workers supplementing military activity in high-risk occupations with uncertain long-term outcomes.


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