Miracle-dz/UniFAR-FTUs huggingface dataset:
Reconciling Cretaceous paleomagnetic and marine magnetic data for Iberia: New Iberian paleomagnetic poles

[1] The Cretaceous paleogeography and the kinematic evolution of the Iberian plate are poorly constrained. Especially problematic is to reconcile Iberian paleomagnetic data with paleomagnetic data of the neighboring plates and with Euler poles derived from seafloor magnetic anomalies. The first limitation arises from the Cretaceous Normal Polarity Superchron where paleogeographic reconstruction using marine magnetic anomalies is handicapped. The second arises from the paucity of reliable paleomagnetic poles with satisfactory statistical criteria and age. In order to address these shortcomings and provide new high quality paleomagnetic poles for Iberia, we conducted a detailed rock magnetic and paleomagnetic study of two Cretaceous magmatic sills, the Paco de Ilhas (PI) and Foz da Fonte (FF) sills, from the Lusitanian Basin, Portugal, recently dated at about 88 and 94 Ma, respectively. Our results show that the magnetic mineralogy of the sills is primary, i.e., acquired during magma cooling, and essentially represented by titanomagnetite. The corresponding paleomagnetic poles match the synthetic APWP from the African plate at 80 and 100 Ma. On the basis of a rigorous selection of Iberian Cretaceous poles, we then calculated mean paleomagnetic poles for different time intervals and found that Iberian paleomagnetic data fit well the global APWP between 70 and 120 Ma, but move far away from the APWP at pre-rift times. Our approach shows that new and better constrained paleomagnetic poles can aide in solving part of the contradiction between Iberian and African APWPs.
Cretaceous fractionated I-type granitoids and metaluminous A-type granites in SE China: the Late Yanshanian post-orogenic magmatism

The Late Yanshanian Orogeny (130-90 Ma) encompasses an important Mesozoic magmatic event in the crustal evolution of SE China. Products of post-orogenic magmatism, widely distributed in the eastern part of Zhejiang and Fujian provinces known as the Southeast Coast Magmatic Belt (SCMB), are dominated by large amounts of slightly Nb and Ta depleted, high-K calc-alkaline granites (I-type) and small amounts of strongly Ba, Sr, Eu, Ti and P depleted, metaluminous granites (A-type). 40Ar/39Ar dating from amphiboles suggests that emplacement of A-type granites mostly postdates (94-90 Ma) the intrusion of voluminous I-type granitoids (110-99 Ma). Using the Al-in-amphibole geobarometer, I-type suites were estimated to have been emplaced at shallow depths (5-7 km). Along with the fact that A-type granites are phyric or miarolitic in texture, it can be concluded that all these post-orogenic suites in the SCMB belong to shallow intrusives. They have also undergone a rapid cooling (higher than 100°C/Ma at T > 300 °C) as indicated by the thermochronology of hornblende, biotite and K-feldspar; therefore, generation of A-type granites from I-type magmas through fractional crystallisation would be a difficult process. Alternatively, their geochemical characteristics are attributed to partial melting in the residual lower crust under an elevated geothermal environment. On the other hand, I-type magmas are considered to be middle-crust-derived melts largely modified with mantle-derived melts that had been depleted with Nb and Ta by earlier tectonic processes. Such a tectonic environment is explained by the underplating of basaltic magmas, most probably due to lithospheric delamination taking place at c. 110 Ma, which marks the beginning of the postorogenic episode in this area. Numerical modelling for a heat source provided by the underplating of basaltic magma supports such a proposition.
Uncertainties in reservoir production forecasts

Being aware of uncertainties in forecasts of production characteristics is important for reservoir management. Decisions concerning further appraisal drilling, flexibility in development plans, and selection among reservoir prospects all require that uncertainties are taken into account. This study addresses the problem of quantifying uncertainties due to incomplete knowledge of the initial reservoir characteristics, with emphasis on the difference between heterogeneity modeling and assessment of uncertainty. In this study we outline a formalism for uncertainty modeling in a Bayesian framework and present an extensive case study of a North Sea Brent Group reservoir. The results are obtained by computer software implemented such that no human interference is required once the stochastic reservoir model is established. Once the stochastic reservoir model is established, multiple realizations can be generated, rescaled, and fed into a fluid flow simulator to forecast production characteristics and quantify uncertainty associated with response parameters such as cumulative oil production, recovery factors, and water cuts. The results demonstrate that uncertainty in model parameters contributes significantly to the overall uncertainty. The most influential parameters in our case study include the sealing capacity of major faults, seismic velocities used in depth conversion, and average porosities and shale continuity within the main reservoir sandstone.
The dynamical response of the middle atmosphere to the tropospheric solar signal

[1] To assess a possible solar modulation of the planetary waves, the 300 hPa geopotential height of the two major reanalysis data sets, NCEP/NCAR and ERA40, is studied for the difference between years of solar maximum and minimum activity for three solar cycles in the period 1963–1999. We find a significant positive difference over the North Pacific ocean for December through February which resembles that found in sea level pressures in earlier studies. Furthermore, there are statistically significant amplitude differences in the climatological state of the first two planetary waves extracted from the geopotential heights. We also perform a model study of the middle atmospheric response to the tropospheric solar signal. The 300 hPa geopotential height is used as the lower boundary in a middle atmosphere model which is run with a constant solar cycle minimum radiative forcing, so that only the lower boundary is forcing the middle atmosphere. The zonal wind and temperature at 300–0.01 hPa from the model experiment are studied in boreal winter for the same years that were studied in the geopotential height analysis. Differences of the means of the two data sets reproduce the structure and amplitude seen in observations and in reanalysis data. Whether this is a direct effect of the solar forcing of the troposphere or a feedback coupling of the solar forcing of the stratosphere is not presently clear, but the modulation of the tropospheric planetary waves seems to be important for the observed solar modulation of the stratosphere.
Phase relations in andalusite-sillimanite type Fe-rich metapelites: Tono contact metamorphic aureole, northeast Japan

Mineral assemblages in metapelites of the contact aureole of the Tono granodiorite mass, northeast Japan, change systematically during progressive metamorphism along an isobaric path at 2-3 kbar. The bulk rock compositions of metapelites are aluminous with A′ values on an AFM projection larger than that of the chlorite join. The metapelites commonly contain paragonite in the low-grade zone. With increasing temperatures, andalusite is formed by the breakdown of paragonite. The importance of pyrophyllite as a source of Al2SiO5 polymorphs is limited in typical pelitic rocks. The most common type of metapelite in the study area has FeO/(FeO + MgO) = 0.5–0.6, and develops assemblages involving chlorite, andalusite, biotite, cordierite, K-feldspar, sillimanite and almandine, with paragenetic changes similar to other andalusite-sillimanite type aureoles. Rocks with FeO/(FeO + MgO) > 0.8 progressively develop chloritoid-bearing assemblages from Bt-Chl-Cld, And-Bt-Cld, to And-Bt at temperatures between the breakdown of paragonite and the appearance of cordierite in the more common pelitic rocks in the aureole. The paragenetic relations are explained by a KFMASH univariant reaction of Chl + Cld = And + Bt located to the low-temperature side of the formation of cordierite by the terminal equilibrium of chlorite. A P-T model depicting the relative stability of chloritoid and staurolite at low- and medium-pressure conditions, respectively, is proposed, based on the derived location of the Chl + Cld = And + Bt reaction combined with the theoretical phase relations among biotite, chlorite, chloritoid, garnet and staurolite.
Early Bartonian orthophragminids (Foraminiferida) from Reineche Limestone, north African platform, Tunisia: taxonomy and paleobiogeographic implications

The orthophragminids in lower Bartonian Reineche Limestone member, a fossiliferous shallow-marine unit exposed in Cap Bon peninsula in Tunisia, are represented by 17 species assigned to Discocyclinidae Galloway 1928 and Orbitoclypeidae Brönnimann 1946. These taxa, associated with nummulitids and alveolinids, belong to the lineages of Discocyclina Gümbel 1870, Nemkovella, 1987, Orbitoclypeus Silvestri 1907, and Asterocyclina Gümbel 1870, described for the first time from north Africa lying at the southern margin of Tethyan ocean during Paleogene. We identified Nemkovella evae, previously not recorded in upper Lutetian/lower Bartonian and younger Eocene deposits of northern Tethyan platforms, and erected a new subspecies, N. evae reinechensis n. ssp. A comparison of Reineche orthophraminids, assigned to orthophragmines zone (OZ) 12 and shallow benthic zone (SBZ 17), to the well-described coeval assemblages at northern Tethyan platforms in Italy, Hungary, Turkey, and to those in Kutch Basin in the Indian subcontinent suggests that some species are confined to certain paleogeographic domains. Orbitoclypeus haynesi, the only orbitoclypeid and the most abundant orthophragminid in lower Bartonian deposits in Kutch, appears to be the most common orbitoclypeid in Reineche Limestone. In Europe, this species is not known and is replaced by Orbitoclypeus varians, the most common orbitoclypeid in middle Eocene of central Europe. Both species occur in varying proportions in marine successions in Turkey. Asterocyclina sireli, identified so far only in Turkey, occurs in Reineche Limestone and in lower Bartonian deposits in Kutch. This species is recorded for the first time in the Indian subcontinent. Relying on present study, as well as our recent studies in Kutch Basin, we conclude that the generic and specific diversity of orthophragminids decreases eastward from the peri-Mediterranean region to Indian subcontinent and to the western Pacific.
A Poisson regression model approach to predicting tropical cyclogenesis in the Australian/southwest Pacific Ocean region using the SOI and saturated equivalent potential temperature gradient as predictors

This paper explores the potential of the Southern Oscillation index (SOI) in combination with the saturated equivalent potential temperature gradient (EPT) as predictors of tropical cyclogenesis in the Australian/southwest Pacific Ocean. This is undertaken using a series of Poisson regression models of tropical cyclogenesis developed on a 2° latitude × 5° longitude and monthly grid. Links between tropical cyclogenesis and the predictors are investigated, with the most significant models cross‐validated, and the skill of their hindcasts evaluated. The September lead SOI‐only Poisson regression model provided skillful predictions of the temporal variability of tropical cyclogenesis across the entire region, with a root‐mean‐square error 22% better than climatology. The combination SOI and EPT model adds spatial skill and further improves temporal skill. Temporal skill is best in the Eastern subregion (western tropical Pacific) (significant correlations with observations at ∼99% level), while spatial skill is best elsewhere.
Depth imaging examples and methodology in the Gulf of Mexico

Advances in seismic imaging over the past several years have revolutionized interpretation of geologic structures in complex areas. Nowhere has the impact of this technology been greater than the Gulf of Mexico, where the ability to interpret structures in subsalt areas has led to very large oil discoveries. Interestingly, although many techniques used in imaging these complex areas are new, the basis for many may be found in the classic methods of time imaging, many of which are still used in large-scale production depth imaging. Inherent in these techniques has been the assumption of a locally flat-layered earth consistent with hyperbolic moveout, which although incorrect for complex areas such as the subsalt imaging in the Gulf of Mexico, carries with it a robustness and determinism. Gradually, depth-imaging techniques are evolving to overcome the limitations of a local flat-layer earth assumption but at the cost of this determinism. For a true depth model, velocities, densities, and other parameters must be determined in a spatially varying way, so there is an explosion in the number of parameters to be determined. A consistent earth model from the depth-imaging perspective relies on measurement redundancy—i.e., reflections from the subsurface appear on traces from numerous source-receiver pairs in the acquisition geometry. The imaging process is then done in a way that produces not one but many images, each created using energy that has traveled through different parts of the earth. Consistency requires that these images agree. Hence, difficulties have shifted from the imaging algorithms themselves, as with the local flat-layer assumption in time imaging, to those associated with the data, their redundancy, and the uncertainty in determining a consistent model. In this article we examine a number of examples of depth imaging in the Gulf of Mexico. In the process we chronicle depth-imaging methods as they …
Methods for determining soil water repellency on field‐moist samples

In this paper we describe a simple and quick method for determining the presence of water repellency in a soil by using a small core sampler (1.5 cm in diameter, 25 cm long) and applying the water drop penetration time (WDPT) test at different depths on the sandy soil cores. Obtained results provide spatial distribution patterns of water repellency in a soil profile, demonstrating seasonal changes in repellency. An advantage of the method is that the soil is not disturbed by the sampling. For assessment of the persistence of water repellency in strongly to extremely water repellent soils, and for determination of the critical soil water contents, the WDPT test and volumetric water content determinations should preferably be performed in the laboratory.
Comparison of catchment grouping methods for flow duration curve estimation at ungauged sites in France

Abstract. The study aims at estimating flow duration curves (FDC) at ungauged sites in France and quantifying the associated uncertainties using a large dataset of 1080 FDCs. The interpolation procedure focuses here on 15 percentiles standardised by the mean annual flow, which is assumed to be known at each site. In particular, this paper discusses the impact of different catchment grouping procedures on the estimation of percentiles by regional regression models. In a first step, five parsimonious FDC parametric models are tested to approximate FDCs at gauged sites. The results show that the model based on the expansion of Empirical Orthogonal Functions (EOF) outperforms the other tested models. In the EOF model, each FDC is interpreted as a linear combination of regional amplitude functions with spatially variable weighting factors corresponding to the parameters of the model. In this approach, only one amplitude function is required to obtain a satisfactory fit with most of the observed curves. Thus, the considered model requires only two parameters to be applicable at ungauged locations. Secondly, homogeneous regions are derived according to hydrological response, on the one hand, and geological, climatic and topographic characteristics on the other hand. Hydrological similarity is assessed through two simple indicators: the concavity index (IC) representing the shape of the dimensionless FDC and the seasonality ratio (SR), which is the ratio of summer and winter median flows. These variables are used as homogeneity criteria in three different methods for grouping catchments: (i) according to an a priori classification of French Hydro-EcoRegions (HERs), (ii) by applying regression tree clustering and (iii) by using neighbourhoods obtained by canonical correlation analysis. Finally, considering all the data, and subsequently for each group obtained through the tested grouping techniques, we derive regression models between physiographic and/or climatic variables and the two parameters of the EOF model. Results on percentile estimation in cross validation show that a significant benefit is obtained by defining homogeneous regions before developing regressions, particularly when grouping methods make use of hydrogeological information.
Climate change research (1991–2012): comparative scientometric study of Argentina, Brazil, China, India and Mexico

This paper attempts to highlight quantitatively the growth and development of climate change literature in terms of publication output as per Web of Science® (1991–2012, September). The focus of this analysis is to study the literature on climate change published from five developing countries namely Argentina, Brazil, China, India and Mexico. This paper is a comparative study on year wise, document type, most productive authors, subject wise, journal wise, institution wise, and language wise distributions. 7065 records have been retrieved for climate change for the studies countries. Country-wise climate change records and most prolific authors for the five countries have been identified. Authorship and collaboration trend was towards multi-authored papers. Institution-wise climate change records for these countries have also been generated. The topper here is Chinese Academy of Science, China (1843 records). We have grouped the listed publications from Web of Science® under “climate change” into six broad subjects among which “Geosciences (multidisciplinary)” has recorded maximum publications (22.4%) followed by “Environmental Sciences” (21.6%) while “Meteorology and atmospheric sciences” has recorded the least (9.3%). English language occupies the first place with 6882 out of 7065 records for the studied countries.
Sediment Melts at Sub-arc Depths: an Experimental Study

The phase and melting relations in subducted pelites have been investigated experimentally at conditions relevant for slabs at sub-arc depths (T¼600^10508C, P¼25^45 GPa). The fluid-present experiments produced a dominant paragenesis consisting of garnet-phengite-clinopyroxene-coesite-kyanite that coexists with a fluid phase at run conditions. Garnet contains detectable amounts of Na2O (up to 05 wt%), P2O5 (up to 056 wt%), and TiO2 (up to 09 wt%) in all experiments. Phengite is stable up to 10008C at 45 GPa and is characterized by high TiO2 contents of up to 2 wt%. The solidus has been determined at 7008C, 25 GPa and is situated between 700 and 7508C at 35GPa. At 8008C, 45 GPa glass was present in the experiments, indicating that at such conditions a hydrous melt is stable. In contrast, at 7008C, 35 and 45 GPa, a solute-rich, non-quenchable aqueous fluid was present.This indicates that the solidus is steeply sloping in P^Tspace. Fluid-present (vapour undersaturated) partial melting of the pelites occurs according to a generalized reaction phengite + omphacite + coesite + fluid = melt + garnet. The H2O content of the produced melt decreases with increasing temperature. The K2O content of the melt is buffered by phengite and increases with increasing temperature from 25 to 10 wt%, whereas Na2O decreases from 7 to 23 wt%. Hence, the melt compositions change from trondhjemitic to granitic with increasing temperature. The K2O/H2O increases strongly as a function of temperature and nature of the fluid phase. It is 00004-0002 in the aqueous fluid, and then increases gradually from about 1 at 750-8008C to about 1 at 1000C in the hydrous melt. This provides evidence that hydrous melts are needed for efficient extraction of K and other large ion lithophile elements from subducted sediments. Primitive subduction-related magmas typically have K2O/H2O of 01^04, indicating that hydrous melts rather than aqueous fluids are responsible for large ion lithophile element transfer in subduction zones and that top-slab temperatures at sub-arc depths are likely to be 700-9008C.
The 1939 Montagneuse River landslide, Alberta

The 1939 landslide on the west wall of the Montagneuse River valley, 1300 m long, 1400 m wide, and 80 m thick with av olume of 76 ×10 6 m 3 , is the largest historic rapid landslide on the Interior Plains of Canada. It lasted about a minute, dammed the river, and formed a reservoir 1.5 km long. The reservoir was filled before 1952 by lake deposits, which were eroded by the river by 1988. The landslide contained two major blocks. The downslope block, 950 m long, kept intact without obvious tilting, indicating that the block moved almost horizontally on a comparatively deep rupture surface. The displaced material included part of the preslide river channel so the Montagneuse River was pushed eastward. The toe of the block moved up and dammed the river. The upslope block, with a length of 300-350 m, slid with little rotation but broke up into at least five smaller blocks. Most trees on the upslope block postdate the slide. Two sag ponds on the landslide, visible in 1952, had enlarged by 1988, probably a result of water running off from the recently cleared farmland behind the scarp. The main scarp has been substantially modified by earth flows and slides. Landslides in the Montagneuse River valley coincide with the Shaftesbury buried preglacial channel of the Peace River. The surfaces of rupture of five historic landslides in the Peace River Lowland follow clays deposited in preglacial channels, confirming that these deposits may be hazardous when eroded.
Dual role of seawater and hydrothermal fluids in Early Archean chert formation: Evidence from silicon isotopes

The great variety and abundance of chert deposits in Archean terrains constitute one of the most unusual features that mark Earth9s early geological history. Proposed explanations for their origin largely relying on field observations, trace element patterns, or oxygen isotope signatures have not yielded an encompassing model. Here we document silicon isotope systematics in cherts from 3.5–3.0 Ga units in the Pilbara Craton (Western Australia) as evidence of their formation by several distinct processes in Early Archean near-surface environments. Our δ 30 Si results, in combination with geochemical and mineralogical signatures and field relations, point to three end-member sources of silica derivation. One chert type is inferred to have originated through massive transformation of precursor material by silica added from sea water. At least 2‰ differences in δ 30 Si between the two other types, produced by direct chemical precipitation on the seafloor or in conduits, discriminate seawater from hydrothermal fluid as a source of silica. A virtually continuous Si isotope trend in cherts from this group is consistent with interaction between silica-carrying fluids at submarine vent systems.