Rapid Permian exhumation of the Montagne Noire dome recorded in provenance of Upper Paleozoic clastics in the Graissessac-Lodève Basin, France

M.S--University of Oklahoma, 2014.Includes bibliographical references (leaves 38-49).The Graissessac-Lodeve Basin (southern France) preserves a thick and exceptionally complete record of continental sedimentation spanning Late Carboniferous through Late Permian time. This section records the localized tectonic and paleogeographic evolution of southern France, in the context of the low-latitude Variscan Belt of Western Europe. This study presents new detrital zircon and framework mineralogy data that address the provenance of Upper Carboniferous-Upper Permian siliciclastic strata exposed in the Graissessac-Lodeve Basin. Detrital zircons in eight samples yielded significant populations that correspond with the ages of regional tectonic events, including: 500-445 Ma (widespread granitic magmatism and volcanism caused by rifting and back-arc extension along the northern Gondwanan margin), 378-331 Ma (high pressure-low temperature metamorphism and deformation during fore-arc compression, and Variscan arc-continent collision), and 330-285 Ma (magmatism, volcanism, and migmatization, chiefly in the southern Massif Central, related to postorogenic extension of the Variscan belt). The ages and compositions of units that constitute the Montagne Noire metamorphic core complex (proximal to the west of the Graissessac-Lodeve Basin) dictate detrital zircon age populations and sandstone framework mineralogy in Permian formations. Cambrian-Archean detrital zircon populations, and metamorphic lithic-rich sandstone framework compositions are derived from recycled detritus of the Neoproterozoic-Early Cambrian metasedimentary Schistes X, which formerly covered the Montagne Noire dome. Ordovician ages and subarkosic framework modes result from erosion of orthogneiss units (deformed granitoid intrusions in the lower Schistes X) that form an "envelope" on the flanks of the dome. In the lower-middle Permian units, the youngest zircon population 330-285 Ma, together with feldspar-rich compositions, reflect derivation from Late Carboniferous-Early Permian granite units in the axial zone of the Montagne Noire. Hence, these data record exhumation, and progressive unroofing of the Montagne Noire dome. The timing of core complex exhumation was previously assumed to have occurred in the Pliocene-Miocene. Our results include 330-285 Ma zircon populations, linked to sandstone compositions of polycrystalline quartz, feldspar, and metamorphic lithic fragments, which persist through the Permian section of the Lodeve Basin (Loiras-Salagou formations). Using estimates of maximum depositional ages, this requires uplift and unroofing of the Montagne Noire core (source terrane) by ca. 295 Ma. The most recent migmatization, magmatism, and deformation occurred at 298 ± 2 Ma, at -17 km depth (based on peak metamorphic conditions in the gneissic core). Accordingly, these new provenance data demonstrate that cooling and exhumation of the core was rapid (3.4-17 mm/year, within error), and early (300-295 Ma), reflecting local paleogeographic uplift in the southern Massif Central during post-orogenic extension. Subsidence analysis of the Graissessac-Lodeve Basin includes rapid initial subsidence( 312 m/My), characteristic of extensional rift basins during formation, followed by subsidence (70 m/My) that persists throughout the Permian, and is interpreted as the crustal response to the hypothesized progressive exhumation and unroofing of the Montagne Noire core complex during the Early Permian

Mesoproterozoic Deposition, Regional Metamorphism and Deformation in North-Central New Mexico: Evidence from Metamorphic Monazite and Detrital Zircon Geochronology in the Picuris Mountains

Detrital zircon and metamorphic monazite ages from the Picuris Mountains, north central New Mexico, were used to confirm the depositional age of the Marquenas Formation, to document the depositional age of the Vadito Group, and to constrain the timing of metamorphism and deformation in the region. Detrital zircon 207Pb/206Pb ages were obtained with the LA-MC-ICPMS from quartzites collected from the type locality of the Marquenas Formation exposed at Cerro de las Marquenas, and from the lower Vadito Group in the southern and eastern Picuris Mountains. The Marquenas Formation sample yields 113 concordant ages including a Mesoproterozoic age population with four grains ca. 1470 Ga, a broad Paleoproterozoic age peak at 1695 Ma, and minor Archean age populations. Data confirm recent findings of Mesoproterozoic detrital zircons reported by Jones et al. (2011), and show that the Marquenas Formation is the youngest lithostratigraphic unit in the Picuris Mountains. Paleoproterozoic and Archean detrital grains in the Marquenas Formation are likely derived from local recycled Vadito Group rocks and ca. 1.75 Ga plutonic complexes, and ca. 1.46 detrital zircons were most likely derived from exposed Mesoproterozoic plutons south of the Picuris. Ninety-five concordant grains from each of two Vadito Group quartzites yield relatively identical unimodal Paleoproterozoic age distributions, with peaks at 1713-1707 Ma. Eastern exposures of quartzite mapped as Marquenas Formation yield detrital zircon age patterns and metamorphic mineral assemblages that are nearly identical to the Vadito Group. On this basis, I tentatively assigned the easternmost quartzite to the Vadito Group. Zircon grains in all samples show low U/Th ratios, welldeveloped concentric zoning, and no evidence of metamorphic overgrowth events, consistent with an igneous origin. North-directed paleocurrent indicators, such as tangential crossbeds (Soegaard & Eriksson, 1986) and other primary sedimentary structures, are preserved in the Marquenas Formation quartzite. Together with pebble-toboulder metaconglomerates in the Marquenas, these observations suggest that this formation was deposited in a braided alluvial plain environment in response to syntectonic uplift to the south of the Picuris Mountains. Metamorphic monazite from two Vadito Group quartzite samples were analyzed with an electron microprobe (EMP). Elemental compositional variation with respect to Th and Y define core and rim domains in monazite grains, and show lower concentrations of Th (1.46-1.52 wt%) and Y (0.67 wt%) in the cores, and higher concentrations of Th (1.98 wt%) and Y (1.06 wt%) in the rims. Results show that Mesoproterozoic core and rim ages from five grains overlap within uncertainty, ranging from 1395-1469 Ma with an average age of 1444 Ma. This 1.44 Ga average age is the dominant timing of metamorphic monazite growth in the region, and represents the timing of metamorphism experienced by the region. An older 1630 Ma core observed in sample CD10-12 may be interpreted as a result of low temperature metamorphism in lower Vadito Group rocks due to heat from ca. 1.65 Ga granitic intrusions. Core ages ca. 1.5 Ga are likely due to a mixing age of two different age domains during analyses. Confirmed sedimentation at 1.48-1.45 Ga and documented mid-crustal regional metamorphism in northern New Mexico ca. 1.44-1.40 are likely associated with a Mesoproterozoic orogenic event

THE EFFECTS OF DARK ENERGY AND BARYONS AND THEIR INTERPLAY ON THE GROWTH OF STRUCTURE

The discovery of the accelerated expansion of our Universe brought with it a new theoretical entity called dark energy. Within our standard model of cosmology, \lcdm{}, this dark energy component is described by a cosmological constant with a small energy density that does not evolve with space or time. Attempts to attribute physical meaning to the cosmological constant have been unsuccessful, culminating in a collection of problems known as the ``cosmological constant problem" and the ``coincidence problem". These have motivated alternative theories of dark energy that aim at relieving some of the theoretically unsatisfactory characteristics of the cosmological constant. Over recent years, observational cosmology has made great leaps in constraining the parameters of the standard model of cosmology. However, with the increasing quantity and quality of data available, a few tensions between different observational probes have started to appear. These have only grown over time and are now of statistical significance. These tensions could have any of the following origins; they arise from unknown and unaccounted systematic errors in the data, from unknown errors in the theoretical modeling and/or from an incomplete model of cosmology. The latter possibility has added motivation for extending the standard model of cosmology, where alternate forms of dark energy are one of many available avenues. The main aim of this work is to explore forms of dark energy with a greater degree of freedom than the cosmological constant. Specifically, dynamical dark energy (DDE) models which allow dark energy to evolve with time and are parametrised by two additional free parameters: $w_0$ and $w_a$. I investigate the current cosmological parameter constraints from a combination of observation data sets and devise a strategy to select 6 cosmologies of interest. I independently modified and ran a total of 12 simulations, evenly split between collissionless and hydrodynamic simulations. Since dark energy affects the expansion history, geometric probes, such as Type Ia supernovae and baryon acoustic oscillations, can constrain the dark energy parameters in a conceptually straightforward manner. However, changes to the expansion history also affect the growth of structure which could make large-scale structure (LSS) statistics potentially powerful and complementary probes. The first part of this work investigates the effect that these cosmologies have on a variety of LSS statistics using large cosmological hydrodynamical simulations. I find that DDE can affect the clustering of matter and haloes at the $\sim10\%$ level, which should be distinguishable with upcoming large-scale structure surveys. DDE cosmologies can also enhance or suppress the halo mass function (with respect to $\Lambda$CDM) over a wide range of halo masses. The internal properties of haloes are minimally affected by changes in DDE, however. The second part of this work investigates the separability of the cosmology and baryonic physics. I quantify to what extent these two processes affect each other, or in other words, how correlated they are. I show that the impact of baryons and associated feedback processes is largely independent of the change in cosmology and that these processes can be modelled separately to typically better than a few percent accuracy

Revising the diagnosis of congenital amusia with the Montreal Battery of Evaluation of Amusia

This article presents a critical survey of the prevalent usage of the Montreal Battery of Evaluation of Amusia (MBEA; Peretz et al., 2003) to assess congenital amusia, a neuro-developmental disorder that has been claimed to be present in 4% of the population (Kalmus and Fry, 1980). It reviews and discusses the current usage of the MBEA in relation to cut-off scores, number of used subtests, manner of testing, and employed statistics, as these vary in the literature. Furthermore, data are presented from a large-scale experiment with 228 German undergraduate students who were assessed with the MBEA and a comprehensive questionnaire. This experiment tested the difference between scores that were obtained in a web-based study (at participants’ homes) and those obtained under laboratory conditions with a computerized version of the MBEA. In addition to traditional statistical procedures, the data were evaluated using Signal Detection Theory (SDT; Green and Swets, 1966), taking into consideration the individual’s ability to discriminate and their response bias. Results show that using SDT for scoring instead of proportion correct offers a bias-free and normally distributed measure of discrimination ability. It is also demonstrated that a diagnosis based on an average score leads to cases of misdiagnosis. The prevalence of congenital amusia is shown to depend highly on the statistical criterion that is applied as cut-off score and on the number of subtests that is considered for the diagnosis. In addition, three different subtypes of amusics were found in our sample. Lastly, significant differences between the web-based and the laboratory group were found, giving rise to questions about the validity of web-based experimentation

Cognition as Embodied Morphological Computation

Cognitive science is considered to be the study of mind (consciousness and thought) and intelligence in humans. Under such definition variety of unsolved/unsolvable problems appear. This article argues for a broad understanding of cognition based on empirical results from i.a. natural sciences, self-organization, artificial intelligence and artificial life, network science and neuroscience, that apart from the high level mental activities in humans, includes sub-symbolic and sub-conscious processes, such as emotions, recognizes cognition in other living beings as well as extended and distributed/social cognition. The new idea of cognition as complex multiscale phenomenon evolved in living organisms based on bodily structures that process information, linking cognitivists and EEEE (embodied, embedded, enactive, extended) cognition approaches with the idea of morphological computation (info-computational self-organisation) in cognizing agents, emerging in evolution through interactions of a (living/cognizing) agent with the environment