Miracle-dz/UniFAR-FTUs huggingface dataset:
Qualitative and quantitative applications of LiDAR imagery in fluvial geomorphology

The potential for geomorphological mapping and quantitative calculations of light detection and ranging (LiDAR) data within fluvial geomorphology was studied for two river catchments within Belgium (Dijle and Amblève), which differ in physical settings and floodplain morphology. Two commercial, of‐the‐shelf LiDAR datasets with different specifications (horizontal resolution and vertical accuracy) were available for parts of the floodplains of both catchments. Real‐time kinematic (RTK) Global Positioning System (GPS) data were used as ground truth for error calculations.
Neotectonic deformation of a Late Weichselian outwash plain by deglaciation‐induced fault reactivation of a deep‐seated graben structure

The Late Weichselian Tinglev outwash plain in southwestern Denmark slopes gently from east to west, but certain areas of the topography show unusual irregularities. Analysis of LiDAR data reveals a mosaic of smaller areas with pronounced changes in slope magnitude and orientation between neighbouring areas. The outwash plain also features notable changes in elevation across kilometre‐long lineaments and areas lying lower and higher than the expected level. The depressions in the area have previously been interpreted as the result of melting dead‐ice blocks left by the Late Weichselian ice sheet. However, borehole samples from Lake Tinglev on the outwash plain show that lake sedimentation did not start until the early Holocene (9000 years ago), which is more than 9000 years after the ice sheet had retreated. The topographical irregularities are located above the Tønder Graben structure, and we interpret these as the result of Holocene strike‐slip movements along the graben faults resulting in areas of both subsidence and uplift. The deformations of the outwash plain are interpreted as the effect of deglaciation tectonics acting within a limited time frame at the beginning of the Holocene. As the event can be related to stress release from the weight of the Scandinavian Ice Sheet, we expect that other fault zones in northern Europe would be equally prone to reactivation. Tectonic events related to deglaciation would most likely be recurrent, and the stress changes appear to have been able to induce short‐lived tectonic instability to areas normally considered tectonically stable. We conclude that this type of tectonics has had a significant impact on topography and sedimentation throughout the Quaternary.
The tourmaline-bearing granite pluton of Bodmin (Cornwall, UK): magnetic fabric study and regional inference

The magnetic fabrics and microstructures of the Variscan granite pluton of Bodmin (Cornwall) have been studied. Its low susceptibility magnitude, consistent with its lack of magnetite, comes from biotite and tourmaline. As the magneto-crystalline behaviour of tourmaline is ‘inverse’ compared with that of the phyllosilicates, the magnetic fabric was remeasured after heating the specimens to enhance the biotite magnetic signal by the growth of mimetic magnetite. The roughly similar magnetic fabrics before and after heating demonstrate that the effect of tourmaline is not important as long as the tourmaline content does not exceed that of the phyllosilicates. Regionally, this study reveals a well-defined NNW trend of the magnetic lineations with opposite plunges on each side of a separation line crossing the pluton centre. This pattern, very similar to that documented in the nearby Carnmenellis pluton, is ascribed to unroofing during emplacement. It agrees with the late to post-magmatic NW stretch that characterizes the Devonian to Carboniferous formations located to the north of this region, the thrust-and-fold structure of which is attributed to southward compression. We conclude that syntectonic emplacement may have characterized the whole Cornubian batholith at the very end of the Variscan orogeny in Cornwall.
Recent Progress (2007–2012) in Permafrost Isotope Geochemistry

This paper reviews contributions to permafrost isotope geochemistry published between 2007 and 2012 and proposes future research directions. It focuses on: (1) the origin and age of ground ice; (2) geochemistry and water movement in the active and transient layers; and (3) geochemistry and water movement in deep permafrost. The use of isotope geochemistry to study permafrost‐related processes has grown significantly over the last few years. These processes have been elucidated by combining geochemical and isotope measurements from different components of permafrost. Such combination has yielded new insights, for example, into the water source and transfer processes that lead to the formation of ground ice, as well as groundwater movement and residence time in permafrost. Permafrost isotope geochemistry has a promising future and should provide valuable tools for the study of a rapidly changing permafrost environment. Copyright © 2013 John Wiley & Sons, Ltd.
Palaeogene non-marine molluscs from Oman: implications for the timing of uplift of the Dhofar Plateau and the opening of the Red Sea and Gulf of Aden

Abstract A collection of terrestrial and freshwater snails from the Late Eocene to earliest Early Oligocene Zalumah Formation at Wadi Darbat, near Salalah, Oman is of importance on account of its taxonomic composition, its palaeoecological indications and its biogeographic affinities which are clearly tropical African; these are very different from the extant non-marine snail fauna of Oman which is typical of the Mediterranean belt. In addition, these fossil snails are by far the oldest-known representatives of their respective genera. The Late Eocene Zalumah deposits which yielded the molluscs accumulated just above sea level, as revealed by the admixture of marine, brackish water and freshwater taxa as well as fully terrestrial gastropods. These deposits now vary in altitude from near sea level at Taqah (Wadi Darbat) to over 930 m at Thaytiniti. Uplift of the Dhofar Plateau therefore must have occurred later than the Early Oligocene. The biogeographic affinities of the snails confirms that the Arabian Peninsula was part of the African continent at the time of deposition and that the opening of the Red Sea and the Gulf of Aden occurred later than the Early Oligocene.
Dislocation model for radon response to distant earthquakes

If radon changes associated with earthquakes are caused by changes in strain within the earth, reports of radon signals that are measured at considerable distances from the hypocenters of earthquakes can be understood. A simple dislocation model leads to estimates of distances that increase to hundreds of kilometers at earthquake magnitudes of 5 and above. The essential components of the theory are that the strain from a dislocation loop varies at large distances x as x−3, while the strains increase with the magnitude of the earthquake represented. A threshold sensitivity is inferred from radon measurements associated with earthquakes near Blue Mountain Lake, New York. The usefulness of a global 222Rn-monitoring network is inferred.
Ocean and land climate dynamics offsoutheast Africa during the late Pleistocene:A multi-proxy approach

The Agulhas Current transport of heat and salt from the Indian Ocean into the South Atlantic around South Africa (Agulhas leakage), can affect the Atlantic Meridional Overturning Circulation (AMOC) and, thus, influence global climate. Upper water column reconstructions in the southwest Indian Ocean over the past 100 kyr based on marine sediments from the core region of the Agulhas Current suggest that surface ocean temperature, salinity and planktonic foraminiferal assemblage records from the Agulhas Current exhibit high variability on orbital to millennial timescales. A high degree of similarity in this variability could also be identified in the Agulhas leakage records in the South Atlantic which suggests that changes in the Agulhas leakage can be partly explained by upstream variability in the Current itself. The results of a benthic stable isotope record from the southwest Indian Ocean over the past 270 kyr gives evidence that during glacial periods as well as during Northern Hemisphere Cold Stadials Southern Component Waters substituted for North Atlantic Deep Waters. The recorded hydrographic variability in the deep southwest Indian Ocean is explained in terms of a less vigorous AMOC exporting a reduced amount of NADW into the Southern Hemisphere and/or at shallower depth causing the observed changes in the deep water inventory. A multiproxy data and model integration approach reveals that phases of more humid southeast Africa climate were driven by southward oscillations of the Intertropical Convergence Zone and its associated rain belt over the past two glacial-interglacial cycles. Low-latitude summer insolation changes paced by orbital precession explain the long-term climate variability whereas abrupt climate oscillations in the northern high latitudes are the main driver for the observed millennial-scale wet phases. Southeast African climate variability seems to have been coupled, and anti-phased, with the East Asian Summer Monsoon during the late Pleistocene. Agulhas Current sea surface temperatures changes did not exert a primary control on southeast African hydrology.
The Principal Nonseasonal Modes of Variation of Global Sea Surface Temperature

Abstract Thirty-five million ship reports for the period 1949–79 have been used to construct global, monthly-mean sea surface temperature fields for 5° × 5° latitude-longitude regions. The monthly means have been subjected to eigenvector analysis to bring out the nonseasonal modes of variation. The El Nino mode is the most important and its eigenvector time series is identical to that found previously by Weare et al. for the Pacific alone. Addition of data from the other oceans adds unexplained variance so that the percentage of the variance explained by the El Nino mode is smaller in the global case than for the Pacific alone. The second most important eigenvector pattern shows evidence of a cooling trend for the North Pacific and North Atlantic in the 1964–79 period. This is in agreement with previous work an zonal-mean sea surface temperature by the authors, with recent work on the North Pacific by Douglas et al. and with a polar-cap cooling in the lower troposphere for the same period reported by Boer.
Geology of Hadley Rille.

Apollo 15 data support the concept that Hadley Rille is a giant collapsed lava tube that originated at its south end. The south half of the rille is sinuous and the bends are not structurally controlled, whereas the north half of the rille follows pre-mare structural troughs. Most of the rille has a V-shaped profile apparently formed by recession of the rims and coalescence of talus from both sides. The rille is scalloped and discontinuous locally, and the deepest parts consistently are the widest. This is a different relationship from that shown by river channels, but can instead be explained by collapse, with most extensive foundering at the deepest points. The upper 60 meters of the walls of the rille at the Apollo 15 site expose several layers of mare basalt. Most are massive units averaging at least 10 m thick; others are layered. Numerous talus blocks derived from the massive outcrops are 10 to 30 m across. The lunar flows are thus both thick and little jointed. The outcrop ledge and blocky talus derived from it are absent where the rille abuts Apennine massifs, showing that the rille cuts through the mare basalt and against massif material.
Stratigraphy and Structures East of Oxford

I. Introduction The Geological Survey 1-inch map of Oxford (1908) shows to the east of the city a remarkable belt of faults, running from north-west to southeast for 12 miles and passing at its nearest point within three miles of Magdalen Bridge. Starting in the Great Oolite and Forest Marble of Islip, the faults cut through the Corallian rocks between Elsfield and Beckley and bound the Corallian limestones of Wheatley. They also shift the Kimeridge Clay, Portland Beds and Shotover Sands of Forest Hill, Great Milton and Great Haseley, as far as the margin of the overstepping Gault. Closer inspection of the map makes it clear that these are by no means simple faults. In fact, no satisfactory interpretation of the structure is possible from the arrangement of outcrops and faults shown on the map. The explanatory memoir (1908), by T. I. Pocock, H. B. Woodward, and G. W. Lamplugh, contains no chapter on structural geology. There are, however, scattered references to structure in the stratigraphical chapters, and these were reproduced without alteration in the second edition (Pringle 1926 1). The authors referred to trough-faulting with displacements of 200 feet and 80 feet, to step-faulting, and to a " general Hne of fracture and displacement " which " owing to the meagre field-evidence, could not be deciphered in detail ". No mention was made of folding, and for the most part the mapping shows that none was envisaged. In the light of experience gained in mapping other “lines of
Testing a new two‐dimensional flood modelling system: analytical tests and application to a flood event

Detailed testing of a new two‐dimensional hydraulic modelling system is presented. The methodology consists of applying the hydraulic model to a set of theoretical tests, for which analytical solutions are known, and then comparing a model simulation with a real flood event. The water‐at‐rest test, three dam‐break tests and the Seiche test constitute the set of tests with analytic solutions. The flood event is the Boscastle 2004 flood, for which observed water levels are available. The model yields results that compare closely with the analytical solutions in all of the tests, except for the Seiche test. When applied to the real flood event, the simulated maximum levels are close to the observed levels. Comparisons with two similar commercial software packages show similar results between the models.
Diurnal variations of minor constituents in the stratosphere modeled as a function of latitude and season

Photodissociation and collision processes in the atmosphere cause significant diurnal variations of short-lived minor constituents, in particular among the group of catalysts HOx, NOx, and ClOx. Results of diurnal variation experiments within the framework of the Oxford zonally averaged model are presented. With 49 collision reactions and 13 photodissociation reactions, the model incorporates the most important processes known at present. The model extends from pole to pole and from the surface to about 60 km with a resolution of π/19 in the horizontal (∼9.5°) and half a pressure scale height in the vertical (∼3.5 km). The basic time increment for the integration is 5 min. Results are compared with experimental data.
Metamorphic P–T conditions and retrograde path of high-pressure Barrovian metamorphic zones near Cairn Leuchan, Caledonian orogen, Scotland

Abstract The metamorphic P–T conditions and associated relationships of the Barrovian zones near Glen Muick were re-examined by focusing on the petrology and thermodynamics of rocks at Cairn Leuchan, where garnetite lenses and layers occur in surrounding garnet amphibolite in the highest-grade sillimanite zone. The representative mineral assemblages in the garnet-rich lenses and garnet amphibolite are garnet + quartz + clinopyroxene + plagioclase + amphibole ± epidote, and garnet + amphibole + quartz + plagioclase ± clinopyroxene ± epidote, respectively. The chemical compositions of constituent minerals are the same in both garnetite and garnet amphibolite. The metamorphic P–T conditions of these rocks were estimated by thermodynamic calculations. The results show that the rocks underwent high-pressure granulite facies metamorphism at P = c. 1.2–1.4 GPa and T = c. 770–800°C followed by amphibolite facies metamorphism at P = c. 0.5–0.8 GPa and T = c. 580–700°C. Integration of our new results with previously published data suggests that the retrograde P–T trajectory of the highest-grade Barrovian metamorphic rocks marks a temperature decrease during decompression from a crustal depth of the high-pressure granulite facies, which is much deeper than previously considered.
TAPHONOMY OF A NOSE DIVE: BONE AND TOOTH DISPLACEMENT AND MINERAL ACCRETION IN AN ICHTHYOSAUR SKULL.

In July 1998, a partially articulated anterior skeleton of Opthalmosaurus was collected from the Redwater Shale Member of the Sundance Formation, Natrona County, WY. The skull was disconnected from the vertebral column at the atlas-axis and rested upside down at a nearly 90 ◦ angle to the bedding. The skull and associated vertebrae are partially encased in at least two generations of concretion. Borings on the partially articulated pectoral girdle, ribs and vertebrae suggest that the specimen was exposed on the sea floor. No such evidence, however, was found on the middle and distal portions of the skull, further suggesting that it was partially driven into the sediment by the impact of the carcass. The bone shows marked plasticity at the middle section of the jaws, suggesting enough inertial damage to cause a ripple effect and a large displacement of distal elements. However, the distal ramus also appears to have been constricted by the sediment enough to hold the teeth better in place at the distal end than at the posterior end of the jaws. Iron-stone and pyrite was noted in the jaws, but not in the foramina or vacuities of the vertebral column. The semi-hollow structure of the jaws may have provided a conduit for mineralization. This skull shows similar damage to that of three other ichthyosaur skulls collected from the Sundance Formation, so analogous conditions of taphonomy may have occurred.
Crustal wave propagation anomaly across the Pyrenean Range. Comparison between observations and numerical simulations

Lg records analysis and numerical modelling of Lg propagation are used to find out to what extent this phase can be seen as a marker of unidentified structural anomalies in the crust. This study is based on Lg propagation through the Pyrenean range from earthquakes located in Spain. We have first evaluated the mean value of the S-wave quality factor for central Spain. We have computed simultaneously the seismic station responses and the source functions. The correction for propagation effects, assuming a homogeneous attenuation and the theoretical calculation of the Lg excitation, lead to the seismic moment of each event. The moment magnitude obtained correlates well with the magnitude proposed by the local networks. This gives a confirmation of the Q model in the low-frequency range (1-5 Hz). As we intended to compare traces of different Spanish earthquakes recorded in France at different epicentral distances, we had to make amplitudes independent of propagation and source effects. Therefore, we corrected the spectral amplitudes for geometrical spreading, anelastic attenuation and normalized them to equal seismic moment. We then plotted the records as a function of group velocity, in order to make up a fan profile along the Pyrenean axis. The resulting section reveals that in the central and the eastern parts of the range, neither the North Pyrenean Fault, nor the Moho jump deduced from seismic-refraction experiments and vertical seismics, seem to affect Lg propagation. However, there is an extinction of the Lg phase in the western part of the chain. The lateral extent of this area is correlated with a zone of positive gravity anomaly, probably linked to the presence of dense material of mantle origin. A numerical simulation in the low-frequency band indicates that the Moho topography inferred from deep seismic soundings does not explain the strength of the observed attenuation. Ray-tracing seismograms show that, at high frequency, the conclusion is the same. The attenuation effect due to lateral variation of structure should not be so strong. We, therefore, think that attenuation of guided waves is not due to large-scale geometry effects, but is due to local properties of the crustal materials, possibly apparent attenuation due to scattering on small-scale heterogeneities.
Intermittent Intense Turbulent Mixing under Ice in the Laptev Sea Continental Shelf

Vertical mixing in the bottom boundary layer and pycnocline of the Laptev Sea is evaluated from a rapidly sampled 12-h time series of microstructure temperature, conductivity, and shear observations collected under 100% sea ice during October 2008. The bottom boundary turbulent kinetic energy dissipation was observed to be enhanced (ϵ ∼ 10−4 W m−3) beyond background levels (ϵ ∼ 10−6 W m−3), extending up to 10 m above the seabed when simulated tidal currents were directed on slope. Upward heat fluxes into the halocline-class waters along the Laptev Sea seabed peaked at ∼4–8 W m−2, averaging out to ∼2 W m−2 over the 12-h sampling period. In the Laptev Sea pycnocline, an isolated 2-h episode of intense dissipation (ϵ ∼ 10−3 W m−3) and vertical diffusivities was observed that was not due to a localized wind event. Observations from an acoustic Doppler current meter moored in the central Laptev Sea near the M2 critical latitude are consistent with a previous model in which mixing episodes are driven by an enhancement of the pycnocline shear resulting from the alignment of the rotating pycnocline shear vector with the under-ice stress vector. Upward cross-pycnocline heat fluxes from the Arctic halocline peaked at ∼54 W m−2, resulting in a 12-h average of ∼12 W m−2. These results highlight the intermittent nature of Arctic shelf sea mixing processes and how these processes can impact the transformation of Arctic Ocean water masses. The observations also clearly demonstrate that absence or presence of sea ice profoundly affects the availability of near-inertial kinetic energy to drive vertical mixing on the Arctic shelves.
The use of Mohr circles in the interpretation of magnetotelluric data

One of Ted Lilley’s many original contributions to electromagnetic geophysics was his introduction of the Mohr circle as an aid in the analysis of the magnetotelluric (MT) impedance tensor. Although well known as a representation of the stress tensor in elasticity theory, the usefulness of Mohr circles was virtually unrecognised by the MT community until the pioneer paper of Lilley (1976). An important difference between the stress tensor and the MT tensor is that the former is real while the latter is complex, which means that the MT tensor must be represented by two Mohr circles rather than one. In his early treatments of MT data, Lilley bypassed this complication by concentrating solely on the real part of the MT tensor, and was able to identify various invariants of the real tensor geometrically on the Mohr circle diagram. In later discussions of the physical interpretation of the seven independent invariants of the complex MT tensor, however, it became necessary to consider both real and imaginary Mohr circles together when seeking a geometrical representation of all the invariants. A significant advance was made with the introduction of the (real) phase tensor by Caldwell, Bibby and Brown (2002). Although the phase tensor has only three independent invariants, they retain the important physical properties of the seven invariants of the MT tensor, and can be displayed graphically in a single Mohr circle diagram. In particular, identification of the dimensionality of the regional conductivity structure becomes a straightforward matter whether or not the data are distorted by near-surface conductivity anomalies. An analysis of MT field data with error bars will be presented using the phase tensor and its Mohr circle representation in order to show when a two- or one-dimensional interpretation of the regional conductivity structure is appropriate and strike angles are calculated for two-dimensional structures.