Three-dimensional field perspective on deformation, flow, and growth of the lower continental crust (Dharwar craton, India

The study of fabric development and juvenile batholith emplacement across the tilted crustal section of the Eastern Dharwar craton shows that horizontal, constrictional deformation affected large volumes of the midcrust and lower crust at the time of regional partial melting and magmatic accretion. Constriction is achieved by a combination of coeval shallow and steep planar fabrics sharing a common horizontal elongation direction, two sets of conjugate strike-slip shears, and extensional shear zones. The Eastern Dharwar craton illustrates an end-member deformation mode by which a particularly weakened lithosphere responds to shortening by developing distributed, horizontal plane strain on a crustal scale, resulting from the combination of crustal shortening and lateral gravity-driven flow. Thinning accompanying constrictional deformation is interpreted as compensating for juvenile magmatic accretion and thickening of greenstone belts and as acting to maintain a stable crustal thickness. Such a midcrustal to lower crustal deformation process may provide a resolution of the batholithic room problem in a softened crust submitted to lateral shortening and may explain nearly isobaric retrograde pressure-temperaturetime paths of high temperature - low pressure high-grade terrains

Strain patterns, décollement and incipient sagducted greenstone terrains in the Archaean Dharwar craton (south India)

The Archaean Dharwar craton is characterized by two greenstone successions: the > 3 Ga Sargur Group and the 3.0-2.5 Ga Dharwar Supergroup. Examples of both successions are described from the region of Jayachamarajapura where they are also distinguished by different tectonic patterns. The younger greenstones have undergone only minor deformation and are only slightly metamorphosed and so provide a good case study of the relative behavior of greenstones in relation to their granite-gneiss country rocks. A detailed structural analysis indicates two strain fields associated with two deformational episodes: D1 and D2. The D1 episode produced dome-and-basin structures and affected merely the older greenstones and the gneisses. The mapped strain field is compatible with the hypothesis that it is associated with the development of diapiric-type gravitational instabilities. The D2 episode affects only the younger greenstone belt, which has the overall geometry of a complex syncline. It is discordant over a complex of gneisses and older greenstones that was deformed during the D1 episode. The base of the discordant cover sequence is tectonized and constitutes a décollement surface. Kinematic criteria at this surface have opposite sense and converge towards the belt axis. These structural features are interpreted in terms of progressive deformation compatible with the incipient development of a sagducting trough. These results are consistent with those obtained from other parts of the craton, where the tectonic evolution appears to reflect mainly relative vertical displacements facilitated by the reheating of continental crust during two major Archaean tectonometamorphic episodes. Copyright © 1996 Elsevier Science Ltd

Archean granite-greenstone tectonics at Kolar (South India): Interplay of diapirism and bulk inhomogeneous contraction during juvenile magmatic accretion

[1] The structural study of the Kolar greenstone belt and surrounding granite-gneiss terrains combined with U-Pb dating reveals that the middle and lower crustal tectonoplutonic pattern of the eastern Dharwar craton developed during a major magmatic accretion event between 2550 and 2530 Ma. The granite-greenstone pattern resulted from the interference of gravity-driven sagging of the greenstones (i.e., diapirism), E-W bulk inhomogeneous shortening combined with horizontal N-S stretching, and syntectonic juvenile pluton emplacement. Bulk inhomogeneous contraction is accommodated by the synchronous development of a pervasive, N-S trending vertical foliation, shallow stretching lineation, and conjugate strike-slip shear zone pattern within and outside the greenstone belt, resulting in regional horizontal pure shear deformation. The plutons around the greenstone belt record regional contraction by developing one set of strike-slip C-S fabrics of the shear zone pattern. The development of the granite-greenstone pattern was coeval and compatible with deformation during juvenile magmatic accretion, melting, and granulite metamorphism in the lower crust. The Kolar example points to a specific crustal rheology that allowed sagduction of the greenstones and regional distributed bulk inhomogeneous strain, due to mechanical homogeneity and low viscosity provided by large-scale melting during the accretion event. This example further suggests specific boundary conditions to the craton that allowed E-W inhomogeneous shortening to be accommodated by N-S stretching and spreading of the crust without significant tectonic thickening. Such tectonoplutonic pattern is specific to the Archean and may develop as a consequence of mantle plume activity in intracontinental settings

Cadre géologique du séisme de Lambesc du 11 juin 1909 (Provence, France) : structure et évolution de l’anticlinal de la Trévaresse

Le séisme de Lambesc du 11 juin 1909 (M = 6) est l’événement instrumental le plus important de l’histoire de France. L’analyse géologique de la zone épicentrale (synthèse, cartographie détaillée et étude tectonique) permet de contraindre l’évolution structurale et morphologique de l’anticlinal de la Trévaresse et de la faille associée ayant produit le séisme. Le pli de la Trévaresse est un anticlinal de rampe “forcé” à vergence sud qui s’est développé sur la faille inverse de la Trévaresse du Miocène terminal au Pliocène et probablement après le Pleistocène inférieur. Au cours des 11 derniers millions d’années, la faille de la Trévaresse a enregistré un taux de déplacement inverse intégré de 0,03 ± 0,02 mm/an et un raccourcissement homogène orienté N005 – N010. La zone de faille est constituée de deux segments principaux (le segment oriental étant associé à une faille frontale aveugle potentiellement active) séparés par un relais associé à une série de plis en échelon compatible avec la faible composante senestre du segment oriental. La combinaison de l’analyse structurale avec les réestimations récentes des paramètres de source du séisme indique que la faille de la Trévaresse doit s’enraciner à une profondeur minimale de 6 km, c’est à dire au niveau de décollement triasique. La décroissance vers l’ouest de la maturité morphologique du chaînon anticlinal et de l’escarpement de faille associé suggère une propagation du pli vers l’ouest lors de l’activation partiellement diachrone des deux segments de la faille

Regolith and landscape evolution in Peninsular India and West Africa: morphoclimatic evolution of the two continents over the Cenozoic

Shields’ surfaces of the tropical belt have been continuously shaped over the Cenozoic under the combined or alternating effects of chemical weathering and mechanical erosion that left stepped relict lateritic paleolandsurfaces exposing different generations and type of regolith in today’s sceneries. These lateritic paleolandscape remnants are well preserved in West Africa and in highland Peninsular India, particularly on Deccan Traps. The stepped character of such paleolandscape remnants allows to describing a common geomorphic sequence of three successive sub-continental scale lateritic paleolandsurfaces on the two sub regions. The first surface is defined by the oldest remnants, which are generally topped by Al-Fe (mostly bauxitic) lateritic duricrusts upon distant kmscale mesas or as larger provinces on high relictual topographic massifs (e.g., Fouta Djalon in West Africa or Nilgiri hills in South India). The relict bauxitic landforms generally dominate from less than ca. 300 m the relicts of a second geomorphic level (so-called “intermediate” surface), which is mantled by ferruginous lateritic duricrusts. The third and last paleolandsurface remnants lie less than ca. 400 m below the bauxitic landforms, and consist in a weathered lateritic pediment that is locally capped by a ferricrete. The ages of these continental-scale lateritic paleolandsurfaces may be bracketed using 40Ar/39Ar dating of K-Mn oxides (cryptomelane) formed in their underlying weathering profiles in the African and Indian contexts [1,2,3]. The first surface is Eocene and correlates with the Eocene climatic optimum (ca. 50 Ma) that is recorded throughout the tropical belt by the production of bauxite. In South India, the Intermediate surface has evolved by dominant chemical weathering since the Late Eocene (ca. 37 Ma) and records peak weathering activity in the Late Oligocene. In West Africa, that paleolandsurface seems to have only record the late Oligocene interval (ca. 29-24 Ma) of intense weathering. Abandonment of the Intermediate landscape as a result of its dissection by the river network took place in the Latest Oligocene on both continents. By contrast, the later pediment seems to have been shaped quite rapidly (ca. 32-29 Ma) and was weathered around the Oligocene- Miocene boundary (ca. 29-24 Ma) in India, whereas it took longer to form (ca. 24-18 Ma) and was weathered mostly during the Mid-Miocene (ca. 18-11 Ma) in West Africa. The contrasts in the morphoclimatic record of the two sub regions are linked to the spatial diversification of climatic regimes after the Eocene climatic optimum. However, the combination of the ages with the elevation differences between each lateritic paleolandsurface documents denudation rates with comparable and very low amplitudes (5-15 m/m.y.) in these two continents over the last 50 Ma. [1] Beauvais A and Chardon D (2013) Geochem Geophys Geosyst 14:1590-1608, doi:10.1002/ggge.20093. [2] Bonnet NJ et al. (2014) Earth Planet Sci Lett 386:126-137, doi:10.1016/j.epsl.2013.11.002 [3] Bonnet NJ et al. (2016) Chem Geol, in press

Identification of a methylation profile for DNMT1-associated autosomal dominant cerebellar ataxia, deafness, and narcolepsy

Background: DNA methylation is an essential epigenetic mark, controlled by DNA methyltransferase (DNMT) proteins, which regulates chromatin structure and gene expression throughout the genome. In this study, we describe a family with adult-onset autosomal dominant cerebellar ataxia with deafness and narcolepsy (ADCA-DN) caused by mutations in the maintenance methyltransferase DNMT1 and assess the DNA methylation profile of these individuals. Results: We report a family with six individuals affected with ADCA-DN; specifically, patients first developed hearing loss and ataxia, followed by narcolepsy, and cognitive decline. We identified a heterozygous DNMT1 variant, c.1709C\u3eT [p.Ala570Val] by Sanger sequencing, which had been previously reported as pathogenic for ADCA-DN and segregated with disease in the family. DNA methylation analysis by high-resolution genome-wide DNA methylation array identified a decrease in CpGs with 0–10 % methylation and 80–95 % methylation and a concomitant increase in sites with 10–30 % methylation and \u3e95 % methylation. This pattern suggests an increase in methylation of normally unmethylated regions, such as promoters and CpG islands, as well as further methylation of highly methylated gene bodies and intergenic regions. Furthermore, a regional analysis identified 82 hypermethylated loci with consistent robust differences across ≥5 consecutive probes compared to our large reference cohort. Conclusions: This report identifies robust changes in the DNA methylation patterns in ADCA-DN patients, which is an important step towards elucidating disease pathogenesis

Ecological Assessment of Everyday Executive Functioning at Home and at School using the BRIEF Questionnaire following Childhood Traumatic Brain Injury (TBI)

IntroductionCognitive and behavioural aspects of executive functioning (EF) are frequently impaired following childhood TBI. The Behavior Rating Inventory of Executive Function (BRIEF) questionnaire provides an ecological assessment of EFs in everyday life in home and school environments. The aims of this study were to describe the dysexecutive disorders in children with TBI using the BRIEF; to compare parent- and teacher-ratings and to analyse the demographic and medical variables influencing outcome.MethodsParticipants: Children/adolescents aged 5–17 years 11 months, referred to a paediatric rehabilitation department following TBI. Outcome measures: the parent–and the teacher-report of the BRIEF were collected during neuropsychological assessment (2009–2014), as well as the teacher-report (from 2014). Age at injury and assessment, parental education and TBI severity were collected.Results194 patients (142 boys) participated in the study [mild (n=13), moderate (n=12) or severe (n=169: mean duration of coma 7.2 days; SD=6.5)]. 193 parent-reports and 28 complete teacher reports of the BRIEF were available. Mean age at injury/assessment were 6.9 (SD=4.4), and 11.8 (SD=3.5) years respectively. According to parent-ratings, children had significantly elevated scores in all BRIEF indices [Global Executive Composite (GEC), Behaviour Regulation Index (BRI), Metacognition Index (MI)], and subscales (mean T-scores 61–64; all P<.0001), with 24% to 48.0% scoring in the clinical range. Teachers’ ratings indicated similar deficits in all sub-scales (mean T-scores 63–70; all P<.001), with 39.3–57.2% scoring in the clinical range. For patients with teacher and parent-reports (n=27), no significant difference was found between parent and teacher ratings, which were significantly correlated (r: .44–.72). Regression analyses indicated that GEC was significantly predicted by older age at assessment. The regression model for BRI was not significant. For MI, younger age at injury and older age at assessment were significant predictors.Discussion and conclusionThis study highlights elevated levels of executive dysfunction in everyday life following childhood TBI, evident in home and school environments. Younger age at injury seems to influence the cognitive rather than the behavioural aspects of EFs, whereas older age at assessment is related to higher levels of complaints, probably due to the increasing levels of expectations

Atomic-layer deposited thulium oxide as a passivation layer on germanium

A comprehensive study of atomic-layer deposited thulium oxide (Tm2O3) on germanium has been conducted using x-ray photoelectron spectroscopy (XPS), vacuum ultra-violet variable angle spectroscopic ellipsometry, high-resolution transmission electron microscopy (HRTEM), and electron energy-loss spectroscopy. The valence band offset is found to be 3.05 ± 0.2 eV for Tm2O3/p-Ge from the Tm 4d centroid and Ge 3p3/2 charge-corrected XPS core-level spectra taken at different sputtering times of a single bulk thulium oxide sample. A negligible downward band bending of ∼0.12 eV is observed during progressive differential charging of Tm 4d peaks. The optical band gap is estimated from the absorption edge and found to be 5.77 eV with an apparent Urbach tail signifying band gap tailing at ∼5.3 eV. The latter has been correlated to HRTEM and electron diffraction results corroborating the polycrystalline nature of the Tm2O3 films. The Tm2O3/Ge interface is found to be rather atomically abrupt with sub-nanometer thickness. In addition, the band line-up of reference GeO2/n-Ge stacks obtained by thermal oxidation has been discussed and derived. The observed low reactivity of thulium oxide on germanium as well as the high effective barriers for holes (∼3 eV) and electrons (∼2 eV) identify Tm2O3 as a strong contender for interfacial layer engineering in future generations of scaled high-κ gate stacks on Ge

Syntectonic mobility of supergene nickel ores of New Caledonia (Southwest Pacific). Evidence from faulted regolith and garnierite veins.

International audienceSupergene nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are tightly controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures have play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. From the observation of time-relationship, textures, and mineralogy of various fracture fills and fault gouges, it may be unambiguously established that active faulting has play a prominent role not only in facilitating drainage and providing room for synkinematic crystallisation of supergene nickel silicate, but also in mobilising already formed sparse nickel ore, giving birth to the very high grade ore nicknamed "green gold"

Frame Theory for Signal Processing in Psychoacoustics

This review chapter aims to strengthen the link between frame theory and signal processing tasks in psychoacoustics. On the one side, the basic concepts of frame theory are presented and some proofs are provided to explain those concepts in some detail. The goal is to reveal to hearing scientists how this mathematical theory could be relevant for their research. In particular, we focus on frame theory in a filter bank approach, which is probably the most relevant view-point for audio signal processing. On the other side, basic psychoacoustic concepts are presented to stimulate mathematicians to apply their knowledge in this field