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Michel et al. (2015) present new radioisotopic age estimates coupled with paleosol data from the Lodeve basin, France that indicate a Pennsylvanian–Permian trend toward aridity that is similar to trends seen in other western equatorial basins across tropical Pangaea. In their comment, Pochat and Van Den Driessche (2015) call into question these newly published U-Pb zircon chemical-abrasion isotope dilution thermal ionization mass spectrometry (CA-IDTIMS) age estimates from volcanic ash layers preserved within the Lodeve Basin. Furthermore, Pochat and Van Den Driessche (2015) reject our assertion that the rates of sediment accumulation for the Carboniferous–Permian strata in the Lodeve basin are in need of recalculation as a result of the new geochronological dates. Finally, Pochat and Van Den Driessche (2015) suggest that the paleosol data presented in Michel et al. (2015) do not provide meaningful proxies of paleoclimate change, and reassert the position presented in Pochat and Van Den Driessche (2011) that sedimentary strata are not strongly affected by paleoclimatic change compared with the influence of tectonic processes of the Lodeve basin.

U–Th–Pb zircon geochronology is an essential tool for quantifying the emplacement, differentiation and thermal evolution of crustal magmatic systems. However, the power of U–Pb zircon dates can be enhanced through complementary characterization of mineral texture and geochemistry, as this permits more detailed interpretations of geochronological datasets than conventionally achieved. Our approach to better relating zircon dates and geological processes consists of a multi-method analytical workflow, including cathodoluminescence imaging (CL), in situ LA-ICPMS/EPMA zircon geochemistry, U–Pb zircon ID-TIMS geochronology, and solution ICPMS zircon Trace Element Analysis (U–Pb TIMS-TEA). These methods are here applied to zircon from the Bergell Intrusion, a composite Alpine pluton preserving a ~ 10 km mid-crustal transect. Hand samples of tonalite, granodiorite and hybridized granitoid each record 250–700 kyr of autocrystic zircon growth. Bergell zircons are ubiquitously zoned with ca. 10 4 –10 6 yr growth histories, as evidenced by ID-TIMS analysis of microsampled fragments from single crystals. U–Pb TIMS-TEA data exhibit compositional trends on multiple spatiotemporal scales, including the handsample -scale, representing in situ differentiation at the emplacement level (e.g., Th/U); lithology -scale, defining trajectories corresponding to the production of tonalitic versus granodioritic magmas (Lu/Hf); and pluton -scale, indicating increasingly-evolved melts over ~1.6 Myr of pluton assembly (Zr/Hf). These absolute TIMS-TEA temporal trends are corroborated by relative LA-ICPMS/EPMA core-to-rim geochemistry. We compare records of trace element evolution from TIMS-TEA, Bergell whole-rock geochemistry, and a global compilation of whole-rock geochemical data. These findings support zircon compositional evolution as a robust indicator of differentiation at local and crustal scales, and provide key empirical constraints on melt differentiation and cooling timescales in the middle crust.

Polyoxopalladates hosting 3d, 4d or 4f central ions form a new class of molecular materials with well-defined, tunable morphology and ions coordination to be considered as model systems for basic research. We investigated the isotropic X-ray absorption near-edge structure (XANES), X-ray magnetic circular dichroism (XMCD), and X-ray magnetic linear dichroism (XMLD) to monitor the influence of symmetry changes on electronic and magnetic properties. After a brief introductory review about recent results on 3d and 4d transition metal ions, we (i) show that a change of the coordination symmetry from cubic eightfold (tetrahedral) to sixfold (octahedral) reduces the magnetic moment of Co2+ significantly and (ii) investigate whether axial distortions can modify the 4f states of trivalent lanthanide ions. While for Gd3+ there is no effect visible within experimental uncertainties, changes were observed for Dy3+ and Ho3+. The results are compared to atomic multiplet calculations including the intra-atomic spin-dipole term 〈 T z 〉 . Furthermore, several experimental pitfalls are discussed that may lead to misinterpretation of X-ray absorption data but can be excluded in the present study.

IODP Hole 1256D penetrates a complete section of upper oceanic crust spread from the East Pacific Rise at a full rate of up to 220 mm/yr. Here we present U Pb zircon data from Hole 1256D gabbroic rocks using isotope dilution-thermal ionization mass spectrometry (ID-TIMS) and secondary ion mass spectrometry (SIMS). Three gabbro samples yielded Th-corrected weighted mean 206Pb/238U SIMS dates of 15.03 ± 0.14 Ma, 15.13 ± 0.35 Ma, and 15.23 ± 0.12 Ma. An ID-TIMS Th-corrected weighted mean 206Pb/238U date of 15.191 ± 0.040 Ma from the first of the three samples provides verification and refinement of the timing of magmatism. The U Pb dates agree with the predicted age of the crust based on marine magnetic anomalies, suggesting the gabbros most likely formed by intrusion and crystallization at or near the ridge axis. Zircons from two of the studied samples have anomalously high Th/U ratios, likely reflecting oxidation of U prior to or during zircon crystallization. The elevated ƒO2 of late stage melts in the axial melt lens may be related to progressive crystallization, assimilation of hydrothermally altered sheeted dikes and gabbros, and/or contamination of the melt lens by seawater derived saline brines.

The primary objective of this study was to investigate and validate a predictive, turbulence based primary breakup model. The ESE model is based on a modeled evolution of the turbulent energy spectrum, and is sufficiently general that it may be applied to a broad range of pressure-atomized spray processes, such as those found in agricultural irrigation, industrial coating, automotive fuel injection, and others. In this study, the governing equations are derived and applied to diesel sprays to address a lack of predictive primary breakup models in literature. Tests are performed to demonstrate that the ESE model is numerically converged and has well-behaved model constants. Drop-size distributions are generated for the dense liquid region and compared with experimental and DNS results obtained from literature. Finally, it is proposed that the ESE model be coupled to an aerodynamically-based secondary breakup model to improve predictive capability under real „diesel-like‟ conditions.

A well-known feature of the ${\mathrm{CaFe}}_{2}{\mathrm{As}}_{2}$-based superconductors is the pressure-induced collapsed tetragonal phase that is commonly ascribed to the formation of an interlayer As--As bond. Using detailed x-ray scattering and spectroscopy, we find that Rh-doped ${\mathrm{Ca}}_{0.8}{\mathrm{Sr}}_{0.2}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ does not undergo a first-order phase transition and that local Fe moments persist despite the formation of interlayer As--As bonds. Our density functional theory calculations reveal that the Fe--As bond geometry is critical for stabilizing magnetism and the pressure-induced drop in the $c$ lattice parameter observed in pure ${\mathrm{CaFe}}_{2}{\mathrm{As}}_{2}$ is mostly due to a constriction within the FeAs planes. The collapsed tetragonal phase emerges when covalent bonding of strongly hybridized Fe $3d$ and As $4p$ states completely wins out over their exchange splitting. Thus the collapsed tetragonal phase is properly understood as a strong covalent phase that is fully nonmagnetic with the As--As bond forming as a by-product.

Author(s): Maguire, Kaitlin Clare; Samuels, Joshua X.; Schmitz, Mark D. | Abstract: The Mascall fauna is a well-known middle Miocene (Barstovian) mammalian assemblage in the Pacific Northwest. It has been collected for over 100 years and collecting intensity has increased since the establishment in 1975 of a national monument enclosing the type area of the formation. Despite its importance to biostratigraphy, biogeography of Barstovian taxa, and paleoecological studies, the fauna at the type locality has not been taxonomically examined in more than 50 years. Evaluation and classification of the stratigraphy of the Mascall Formation (Bestland et al. 2008) has prompted a faunal revision in order to place taxa within the new stratigraphic framework. Here we report on the fauna from the type area of the Mascall Formation in central Oregon, and conclude that 20 taxa are new to the fauna, and several taxa previously assigned to distinct species are synonymized. We also place specimens and taxa within a robust stratigraphic framework, calibrated with new U-Pb radioisotopic ages for the Mascall Tuff (15.122±0.017 Ma), the most fossiliferous layer in the formation, and the Kangaroo Tuff (13.564±0.018 Ma), the upper most tuff in the formation.

Here, we document a detailed characterisation of two zircon gemstones, GZ7 and GZ8. Both stones had the same mass at 19.2 carats (3.84 g) each; both came from placer deposits in the Ratnapura district, Sri Lanka. The U‐Pb data are in both cases concordant within the uncertainties of decay constants and yield weighted mean 206Pb/238U ages (95% confidence uncertainty) of 530.26 Ma ± 0.05 Ma (GZ7) and 543.92 Ma ± 0.06 Ma (GZ8). Neither GZ7 nor GZ8 have been subjected to any gem enhancement by heating. Structure‐related parameters correspond well with the calculated alpha doses of 1.48 × 1018 g−1 (GZ7) and 2.53 × 1018 g−1 (GZ8), respectively, and the (U‐Th)/He ages of 438 Ma ± 3 Ma (2s) for GZ7 and 426 Ma ± 9 Ma (2s) for GZ8 are typical of unheated zircon from Sri Lanka. The mean U mass fractions are 680 μg g−1 (GZ7) and 1305 μg g−1 (GZ8). The two zircon samples are proposed as reference materials for SIMS (secondary ion mass spectrometry) U‐Pb geochronology. In addition, GZ7 (Ti mass fractions 25.08 μg g−1 ± 0.18 μg g−1; 95% confidence uncertainty) may prove useful as reference material for Ti‐in‐zircon temperature estimates., Geostandards and Geoanalytical Research, 42 (4), ISSN:1639-4488, ISSN:1751-908X

Objective: There are just a few reports on Color Doppler Ultrasound-guided PTBD with and without metal stent implantation by endoscopic control. Ultrasound guidance facilitates percutaneous bile duct access and avoids severe adverse events. Internal biliary drainage rate in PTBD should be as high as possible as endoscopic ultrasound-guided cholangiodrainage (EUCD) offers internal drainage regularly. We report our prospective study analyzing success, internal drainage and adverse event rates. Materials and methods: Between June 2009 and November 2014 overall 63 PTBDs were performed prospectively in 37 patients (18 m, 19f; age on average: 72 years) with benign (9 %) and malignant (91 %) bile duct obstruction. Ultrasound was used in combination with fluoroscopic guidance. Whenever possible, primary or early secondary metal stent implantation via PTBD by endoscopic control was performed as a one step-procedure. Results: 38 of 41 (93 %) initial PTBDs (in four patients PTBD was performed twice) were successful. 22 of 63 PTBDs were follow-up examinations with different interventions. In 34 of 38 successful (89 %) PTBDs, an internal drainage (or metal stent) was implanted. 12 metal stent implantations via PTBD were performed under endoscopic control. Just 2 (5 %) permanent external drainages were inserted. In 63 performed PTBDs 5 (7.9 %) early major adverse events (no severe intrahepatic bleeding) were documented and treated without any procedure related death. When metal stent implantation was performed via PTBD no adverse event was documented. Conclusion: Color Doppler guided PTBD is an effective and safe method for biliary drainage avoiding severe adverse events. Primary or early secondary metal stent implantation via PTBD reduces complication risks additionally. Endoscopic control of stent implantation via PTBD is helpful for optimal stent placement.

Twenty-eight new high-precision Chemical Abrasion Isotope Dilution Thermal Ionisation Mass Spectrometry U-Pb zircon dates for tuffs in the Sydney and Bowen Basins are reported. Based on these new dates, the Guadalupian-Lopingian/Capitanian-Wuchiapingian boundary is tentatively placed at the level of the Thirroul Sandstone in the lower part of the Illawarra Coal Measures in the Sydney Basin. The Wuchiapingian-Changhsingian boundary is at or close to the Kembla Sandstone horizon in the Illawarra Coal Measures, southern Sydney Basin, in the middle part of the Newcastle Coal Measures in the northern Sydney Basin, and in the middle of the Black Alley Shale in the southern Bowen Basin. The end-Permian mass extinction is recognised at the base of the Coal Cliff Sandstone in the southern Sydney Basin, at the top of the Newcastle Coal Measures in the northern Sydney Basin, and close to the base of the Rewan Group in the Bowen Basin and is dated at c. 252.2 Ma. The end-Permian mass extinction is interpreted to be synchronous globally in both marine and terrestrial environments, and in high and low latitudes (resolution

Paleosols preserved within the Carboniferous–Permian succession of the Lodeve Basin, Massif Central, France change stratigraphically from Histosols to calcic Vertisols and Calcisols to gypsic Vertisols and ultimately back to calcic Vertisols and Calcisols. New high-precision U–Pb zircon ages (CA-IDTIMS) for tuff beds within the Lodeve and adjacent Graissessac basins significantly revise the chronostratigraphy of these and correlated Permian terrestrial basins of eastern Euramerica. Under the newly revised chronostratigraphy presented here these stratigraphic changes in morphology indicate a substantial drying of paleoenvironments across the Carboniferous–Permian boundary with a trend toward progressively more arid and seasonal climates through most of the early Permian. This newly-realized chronology provides a paleoenvironmental and paleoclimatic timeline for eastern tropical Pangea that is contemporaneous with similar records in western Pangea and suggests pan-tropical, progressive climate change toward aridity and seasonality occurred from the Late Carboniferous through early Permian.

In this article we report on the synthesis and multiferroic properties of cobalt ferrite (CoFe2O4)–barium titanate (BaTiO3) biphasic composites. The initial composite nanopowder was synthesized by a combination of co-precipitation and organosol methods. A ceramic sample with (3–0) connectivity, i.e. BaTiO3 grains in a CoFe2O4 matrix was obtained by a combination of spark plasma sintering and annealing. In order to understand the correlations between morphology, electric properties, and magnetization, we present a detailed study at different preparation steps and compare it to the properties of a conventionally sintered sample with the traditional (0–3) connectivity, i.e. CoFe2O4 grains in a BaTiO3 matrix. We observe that the (3–0) sample shows improved magnetic properties in comparison to the conventionally sintered composite of the same composition. In spite of relatively large leakage current for the (3–0) sample compared to the traditional (0–3) one, it exhibits a converse magnetoelectric effect that follows the Hdc dependence of the piezomagnetic coefficient. The magnetic field-dependence of electric polarization at the surface was investigated utilizing X-ray absorption spectroscopy and its associated linear and circular dichroisms.

New U-Pb and Sm-Nd data from the Blue Mountains province, eastern Oregon and western Idaho, clarify terrane correlations and regional evolution of the western Laurentian plate margin during Mesozoic time. We report an Early Jurassic age for a red tuff unit at Pittsburg Landing, Idaho, which is 25 m.yr. older than previous Middle Jurassic estimates. In the Coon Hollow Formation at Pittsburg Landing and at the type location on the Snake River, chemical abrasion thermal ionization mass spectrometry U-Pb zircon ages on interbedded tuff and detrital zircon U-Pb maximum depositional ages indicate that deposition spanned ca. 160–150 Ma, entirely during Late Jurassic time. Detrital zircon U-Pb ages represent local Wallowa arc basement and regional magmatic sources spanning ca. 290–140 Ma. Mudrock Nd isotope compositions of the Coon Hollow Formation record an increase in juvenile magmatism consistent with regional Late Jurassic trends in western North American magmatic systems. These data show that the Coo...

The Kikiktat volcanics (new name) of the northeastern Brooks Range of Arctic Alaska are exceptionally well-preserved Neoproterozoic continental tholeiites. This volcanic suite includes high-temperature picritic compositions, making them an excellent probe of mantle composition and temperature underlying the northern margin of Laurentia during the breakup of Rodinia. Detrital zircons from a volcaniclastic sample directly overlying basaltic flows of the Kikiktat volcanics were dated at 719.47 ± 0.29 Ma by U-Pb chemical abrasion–thermal ionization mass spectrometry. This age suggests that the Kikiktat volcanics are an extension of the Franklin large igneous province. Petrogenetic modeling indicates a simple crystallization sequence of olivine → plagioclase → clinopyroxene, recording anhydrous low-pressure fractionation of a picritic parental melt. The composition of this parental liquid requires melting of harzburgite in the spinel stability field, while temperature estimates of the primary melt indicate elevated mantle potential temperatures. In contrast to the ca. 720 Ma Natkusiak basalts of Victoria Island, the Kikiktat volcanics have very low Ti concentrations, consistent with melting of harzburgitic mantle possibly by thermal conduction of an underlying plume. These data are consistent with Neoproterozoic to early Paleozoic tectonic reconstructions that restore the North Slope of Arctic Alaska to the northeastern margin of Laurentia and not directly adjacent to Victoria Island.

In this Letter we characterize both the photophysical and plasmonic enhanced photophysical properties of carbon nanodots produced by a combustion method. In addition, we have found that max entropy analysis of luminescence decay reveals inhomogeneous distribution of radiative lifetimes. Further, while quantum yields of intrinsic carbon nanodots emission are low [

We use a multiscale approach linking ab initio calculations for the parametrization of an atomistic spin model with spin dynamics simulations based on the stochastic Landau-Lifshitz-Gilbert equation to investigate the thermal magnetic properties of the ferrimagnetic rare-earth transition-metal intermetallic ${\mathrm{DyCo}}_{5}$. Our theoretical findings are compared to elemental resolved measurements on ${\mathrm{DyCo}}_{5}$ thin films using the x-ray magnetic circular dichroism technique. With our model, we are able to accurately compute the complex temperature dependence of the magnetization. The simulations yield a Curie temperature of ${T}_{\mathrm{C}}=1030\phantom{\rule{0.28em}{0ex}}\text{K}$ and a compensation point of ${T}_{\mathrm{comp}}=164\phantom{\rule{0.28em}{0ex}}\text{K}$, which is in a good agreement with our experimental result of ${T}_{\mathrm{comp}}=120\phantom{\rule{0.28em}{0ex}}\text{K}$. The spin reorientation transition is a consequence of competing elemental magnetocrystalline anisotropies in connection with different degrees of thermal demagnetization in the Dy and Co sublattices. Experimentally, we find this spin reorientation in a region from ${T}_{\mathrm{SR}1,2}=320$ to $360\phantom{\rule{0.28em}{0ex}}\text{K}$, whereas in our simulations the Co anisotropy appears to be underestimated, shifting the spin reorientation to higher temperatures.

The Río Chico Group in the San Jorge Basin of central Patagonia (Argentina) preserves some of South America’s most significant Paleogene records of biotic and climatic change. Three of its constituent formations, the Peñas Coloradas, Las Flores, and KoluelKaike, host vertebrate faunas referred to the “Carodnia faunal zone,” the Itaboraian South American Land Mammal Age (SALMA), and the Riochican SALMA. However, the precise absolute ages of these units, and thus their associated faunas and paleoclimate records, are poorly resolved. Herein, we report new paleomagnetic and geochronologic results from these formations in south-central Chubut Province, Argentina. U-Pb dating of four volcanic ashes, using both laser ablation– multicollector–inductively coupled plasma– mass spectrometry and high-resolution chemical abrasion–isotope dilution–thermal ionization mass spectrometry, indicates ages of igneous crystallization of 51.403 ± 0.037 (0.045) [0.071] Ma for a level within the middle Las Flores Formation and 46.714 ± 0.012 (0.026) [0.057] Ma, 44.579 ± 0.013 (0.026) [0.054] Ma, and 42.856 ± 0.017 (0.027) [0.054] Ma for levels in the lower, middle, and upper Koluel-Kaike Formation, respectively. Combining these with previous isotopic ages in our new magnetostratigraphic framework, we correlate the Peñas Coloradas Formation to chrons C27n-26r (ca. 62.5 to ca. 61.6 Ma; late Danian) and the section from the middle Las Flores to the uppermost Koluel-Kaike to chrons C23n to C19r (ca. 51.4–42.2 Ma; mid Ypresian–late Lutetian). We combine these data with other recently published chronostratigraphic results from Paleogene units in Patagonia to better constrain the ages of noteworthy Paleogene plant and mammal fossil sites in Patagonia and to develop a revised temporal calibration of the Las Flores, Vacan, and “Sapoan” faunas. Fil: Krause, Javier Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentina Fil: Clyde, William C.. University of New Hampshire; Estados Unidos Fil: Ibañez Mejía, Mauricio. Massachusetts Institute of Technology; Estados Unidos. University of Rochester; Estados Unidos Fil: Schmitz, Mark D.. Boise State University; Estados Unidos Fil: Barnum, Timothy. University of New Hampshire; Estados Unidos Fil: Bellosi, Eduardo Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Wilf, Peter. State University of Pennsylvania; Estados Unidos

The Eocene Heart Mountain slide of northwest Wyoming covers an area of as much as 5000 km2 and includes allochthonous Paleozoic carbonate and Eocene volcanic rocks with a run-out distance of as much as 85 km. Recent geochronologic data indicated that the emplacement of the slide event occurred at ∼48.9 Ma, using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) extracted from U-Pb zircon ages from basal layer and injectite carbonate ultracataclasite (CUC). We now refine that age with U-Pb results from a lamprophyre diatreme that is temporally and spatially related to the CUC injectites. The ages for the lamprophyre zircons are 48.97 ± 0.36 Ma (LA-ICPMS) and 49.19 ±0.02 Ma (chemical abrasion isotope dilution thermal ionization mass spectrometry). Thus, the lamprophyre and CUC zircons are identical in age, and we interpret that the zircons in the CUC were derived from the lamprophyre during slide emplacement. Moreover, the intrusion of the lamprophyre diatreme provided the trigger mechanism for the Heart Mountain slide. Additional structural data are presented for a variety of calcite twinning strains, results from anisotropy of magnetic susceptibility for the lamprophyre and CUC injectites and alternating-field demagnetization on the lamprophyre, to help constrain slide dynamics. These data indicate that White Mountain experienced a rotation about a vertical axis and minimum of 35° of counterclockwise motion during emplacement.

A potential zircon reference material (BB zircon) for laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb geochronology and Hf isotope geochemistry is described. A batch of twenty zircon megacrysts (0.5–1.5 cm3) from Sri Lanka was studied. Within-grain rare earth element (REE) compositions are largely homogeneous, albeit with some variation seen between fractured and homogeneous domains. Excluding fractured cathodoluminescence bright domains, the variation in U content for all analysed crystals ranged from 227 to 368 μg g−1 and the average Th/U ratios were between 0.20 and 0.47. The Hf isotope composition (0.56–0.84 g/100 g Hf) is homogeneous within and between the grains – mean 176Hf/177Hf of 0.281674 ± 0.000018 (2s). The calculated alpha dose of 0.59 × 1018 g−1 for a number of BB grains falls within the trend of previously studied, untreated zircon samples from Sri Lanka. Aliquots of the same crystal (analysed by ID-TIMS in four different laboratories) gave consistent U-Pb ages with excellent measurement reproducibility (0.1–0.4% RSD). Interlaboratory assessment (by LA-ICP-MS) from individual crystals returned results that are within uncertainty equivalent to the TIMS ages. Finally, we report on within- and between-grain homogeneity of the oxygen isotope systematic of four BB crystals (13.16‰ VSMOW).

The understanding of molecular mechanisms of cancer biology has greatly increased over the past decade. Additional hallmarks of cancer, such as immune tolerance and deregulation of cellular energetics, have been recognized. Targeted cancer therapy aims to interfere with every hallmark of cancer. Potential novel targets are constantly being identified and evaluated. Novel cancer therapeutics that are efficacious in a subset of tumors are on their way to the clinic. Biomarker strategies for patient stratification and evaluation of patient benefit are critical for the efficient use of these personalized medicines. This article gives an overview of different fields of targeted cancer drug discovery and strategies to validate novel targets and biomarkers.

Understanding the time scales of magmatic differentiation, storage, and eruption of large-volume silicic magmas is a primary goal of igneous petrology. Within the Huckleberry Ridge Tuff (HRT; Idaho, USA), representing the earliest and largest caldera-forming eruption associated with Yellowstone volcanic activity, zircon morphological zoning patterns coupled to strongly correlated changes in Ti-in-zircon thermometry and trace element indicators of progressive differentiation provide a proxy record for the evolution of the HRT member B magma body. Tandem in situ and isotope dilution U-Pb dating of single zircon crystals demonstrates an absence of pre-Pleistocene xenocrysts, but reveals the presence of antecrysts recycled from pre-caldera rhyolites in the HRT magma. The petrochronologic interpretation of autocrystic zircon thermal, chemical, and temporal characteristics suggests that HRT member B differentiated over ∼10 k.y. prior to eruption at 2.0794 ± 0.0046 Ma as defined by new astronomically calibrated, single-crystal total fusion 40 Ar/ 39 Ar sanidine analyses. This refined eruption age demonstrates that the transitional polarity preserved by HRT member B does not record the Reunion subchron, but rather a separate, younger geomagnetic event. Our novel approach places the thermal and chemical regime of silicic magmas within a temporal context and demonstrates the rapid evolution of a large volume of silicic magma.

[1] We present an efficient method for high-volume heavy mineral separation from clay-rich rocks using an ultrasonic probe. The ultrasonic clay separator (UCS) is an easily constructed device that allows for the recovery of high-density minerals, as small as 10 µm, with a minimum of sample preparation. Heavy mineral recovery from clay-rich material with the UCS yields a greater number of small (

A model of cyclic recurrence (~ 0.6–1.2 myr) of three fusulinid assemblages in the Middle Pennsylvanian siliciclastic–carbonate succession of the Donets Basin is proposed. Each cycle records progressive turnover of assemblages in shallow marine environments in response to sea-level and regional climate change. A Hemifusulina -assemblage (A), adapted to cooler and reduced salinity seawater records the onset of sea level rise accompanied by humid climatic conditions. Sea level high stand is captured by the Beedeina – Neostaffella – Ozawainella – Taitzehoella (or Beedeina -dominated) assemblage (B), characteristic of relatively deeper-water environments. The B assemblage is successively replaced by the most diverse population of the warm-water Fusulinella -dominated assemblage (C). This assemblage, which occurs in the upper limestones of each fusulinid cycle records the onset of sea level fall accompanied by a shift to drier conditions and likely increased seawater salinity. The proposed model permits robust interbasinal correlation of the Pennsylvanian successions of the Tethyan realm. Fusulinids of the A and C 2 assemblages are the most provincial and therefore the most useful for paleogeographic reconstructions. Specifically, they delineate originally contiguous regions that subsequently were dispersed hundreds to thousands of kilometers, whereas fusulinids of the B assemblage hold the highest potential for global correlation. Extinction at the Moscovian–Kasimovian transition of fusulinid genera of the A and B assemblages, which inhabited predominately cooler and normal salinity (perhaps hyposaline) waters, can be explained by the onset of global warming in the earliest Late Pennsylvanian. Fusulinid assemblages define various types of distribution patterns that differ by tectonic setting of the studied basins suggesting that fusulinid assemblage patterns hold potential for reconstructing the paleogeography and tectonic evolution of Pennsylvanian basins of eastern Laurasia.

The Cloverly Formation is an important geologic unit for understanding the development of North American terrestrial landscapes and ecosystems, but the age of this unit is poorly constrained. We report U–Pb radiometric dates determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and chemical abrasion thermal ionization mass spectrometry (CA-TIMS) from euhedral zircons derived from fluvial sandstone and bentonitic claystone. We reanalyzed published biostratigraphic, paleomagnetic, and radiometric datasets, which have generally disregarded younger (late Albian–Cenomanian) ages for the formation. New data reported in this study suggest that deposition of the Cloverly Formation spanned the Valanginian–Cenomanian stages (ca. 140 Ma–98 Ma), a longer time interval than the commonly cited Aptian–Albian depositional timeframe. The lowest member of the Cloverly Formation, the Pryor Conglomerate, was deposited ca. 140–130 Ma in response to the onset of the Sevier Orogeny shedding sediment from the west. The overlying Little Sheep Mudstone Member was deposited ca. 124–109 Ma in a time of low sediment supply. In the mid–late Albian to early Cenomanian (ca. 109–98 Ma), sediment sourced from the east was deposited as the Himes Member and Greybull Sandstone. Following this, the Sykes Mountain Formation began nearshore deposition as the Western Interior Seaway transgressed from the north. Our revised chronostratigraphic framework for the Cloverly Formation is congruent with tectonic subsidence analysis showing a rapid increase in accommodation space in the mid-Albian. We hypothesize that more intensive sampling may yield multiple fossil assemblages within the formation, paralleling its correlates to the south. Furthermore, we hypothesize that some poorly represented taxa will be synonymized with taxa from those same units now that their temporal equivalence has been demonstrated.

The Ediacaran Jibalah Group comprises volcano-sedimentary successions that filled small fault-bound basins along the NW–SE-trending Najd fault system in the eastern ArabianNubian Shield. Like several other Jibalah basins, the Antaq basin contains exquisitely preserved sedimentary structures and felsic tuffs, and hence is an excellent candidate for calibrating late Ediacaran Earth history. Shallow-marine strata from the upper Jibalah Group (Muraykhah Formation) contain a diversity of load structures and intimately related textured organic (microbial) surfaces, along with a fragment of a structure closely resembling an Ediacaran frond fossil and a possible specimen of Aspidella. Interspersed carbonate beds through the Muraykhah Formation record a positive d 13 C shift from 6t o 0&. U-Pb zircon geochronology indicates a maximum depositional age of ~570 Ma for the upper Jibalah Group, consistent with previous age estimates. Although this age overlaps with that of the upper Huqf Supergroup in nearby Oman, these sequences were deposited in contrasting tectonic settings on opposite sides of the final suture of the East African Orogen.

U-Pb zircon data from the uppermost Cottons Breccia, representing the Marinoan glacial-postglacial transition on King Island, Tasmania, provide the first direct age constraint on the Cryogenian-Ediacaran boundary in Australia. Zircons in four samples from the topmost meter of the Cottons Breccia, dated by sensitive high-resolution ion microprobe, exhibit two modes ca. 660 Ma and ca. 635 Ma. The younger component predominates in the uppermost sample, a possibly volcanolithic dolomitic sandstone, apparently lacking glacially transported debris, in the transition to cap carbonate. Chemical abrasion–thermal ionization mass spectrometry (CA-TIMS) U-Pb dating of euhedral zircons from that sample yields a weighted-mean age of 636.41 ± 0.45 Ma. Equivalence to published TIMS ash bed dates from Cryogenian-Ediacaran transitional strata in Namibia (635.51 ± 0.82 Ma, within glacial deposit) and China (635.23 ± 0.84 Ma, 2 m above glacial deposit) supports correlation of those strata to the Australian type sections and globally synchronous deglaciation at the end of the Cryogenian Period.

This article analyzes the impact of removing the U.S. tobacco program in both a partial and general welfare economics framework. In a partial-equilibrium framework, a consumer tax-funded quota buyout can result in producer gains, consumer losses, net losses resulting from higher prices, and deadweight losses. In a general-equilibrium framework, society can gain from the buyout resulting from considerable potential savings from reduced healthcare costs attributable to a reduction in smoking. Additionally, we present a model that addresses the addictive qualities of tobacco while considering the effects of the quota buyout. We also conclude that another possible effect of the buyout is an increase in worker productivity because employees who are able to quit smoking reduce the amount of smoking-related sick days taken.

We report results from a 40 Ar/ 39 Ar sanidine and CA-TIMS 238 U/ 206 Pb zircon dating study of eruption and crystal residence timescales of the Alder Creek Rhyolite (ACR), California, extruded during the Cobb Mountain normal-polarity subchron (C1r.2n). A 40 Ar/ 39 Ar ACR sanidine date of 1.1850 ± 0.0016 Ma (2σ external uncertainty), determined relative to the astronomically dated A1 tephra sanidine, is interpreted as the ACR eruption age. This age is supported by CA-TIMS U–Pb zircon dating, guided by LA-ICPMS trace element analyses, titanium-in-zircon (TiZR) thermometry, and cathodoluminescence (CL) imaging. Using these data, two compositionally distinct zircon populations were revealed. “Pre-ACR” Group B zircon exhibit oscillatory zoning, large positive Ce and negative Eu anomalies, high incompatible trace element contents, TiZR temperatures of 650 °C–750 °C, and Th/U disequilibrium corrected 238 U/ 206 Pb dates of 1.38–1.24 Ma. These crystals are interpreted as antecrysts inherited from earlier intrusives in the Geysers–Cobb Mountain magma source region. “ACR-related” Group A zircon, present as discrete grains and overgrowths on Group B zircon, display less intense CL with diffuse zoning, and have less pronounced positive Ce and negative Eu anomalies, lower incompatible trace element contents, higher TiZR temperatures that range up to 840 °C, and significantly younger dates. The youngest Group A dates yield a weighted mean of 1.1978 ± 0.0046 Ma (2σ, including systematic uncertainties) that is interpreted as the mean age of zircon crystallization prior to eruption. The 13 ± 5 ka offset between the 40 Ar/ 39 Ar and 238 U/ 206 Pb dates can be attributed to zircon magma residence time. Recognition of a young population of ACR zircon is consistent with the 40 Ar/ 39 Ar eruption age, which coincides with the astronomical age estimate for the Cobb Mountain subchron determined by correlating the oxygen isotope record of the giant piston core MD972143 to the La93 (1,1) orbital solution. On the basis of independent radio-isotopic and orbital forcing results, we propose the refined age of 1.1850 ± 0.0016 Ma (2σ external uncertainty) for the Quaternary ACR 40 Ar/ 39 Ar sanidine standard.

A 4-year-old boy was admitted to this hospital because of fever and abdominal pain. Imaging revealed a periappendiceal mass; purulent fluid was aspirated, and symptoms resolved with antibiotics. One week later, pain recurred. A diagnostic procedure was performed.