Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium-sodium-bicarbonate, sodium-bicarbonate, and sodium-chloride rich waters—indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale-gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale-gas extraction.

[1] Kinematic, kinematic vorticity (W m ), and deformation temperature analyses were completed to test the hypothesis that midcrustal rocks exposed in the core of the Kangmar gneiss dome, southern Tibet record ductile deformation patterns of a "frozen" segment of a southward flowing midcrustal channel. Microscopic and mesoscopic kinematic indicators exhibit a downward transition from a subequal mix of top-north and top-south shear in garnet zone rocks to dominantly top-north shear in staurolite/kyanite zone and deeper rocks. Kinematic vorticity values indicate an increase in pure shear component with depth from ∼48% pure shear in chloritoid zone rocks through ∼62% in garnet zone to staurolite/kyanite zone rocks to ∼68% pure shear in an orthogneiss, the deepest exposed rocks. Deformation temperatures inferred from grain-scale microstructures and quartz lattice preferred orientations increase from ∼300°C-400°C in chloritoid zone rocks to ≥600°C in the deepest exposed rocks. These temperatures are equivalent to temperatures derived from garnet-biotite thermobarometry, indicating that W m was recorded during peak metamorphism. This ductile deformation zone was cut by the brittle southern Tibetan detachment system (STDS) that juxtaposed metasedimentary rocks upon the orthogneiss. On the basis of these relations, midcrustal rocks in the core of Kangmar Dome record: (1) general shear (vertical thinning and N-S horizontal extension) with a component of topnorth shear during peak metamorphism within a ductile shear zone corresponding to the northern and deeper portion of the STDS, (2) an increase in pure shear with structural depth, a consequence of an increase in lithostatic load, and (3) displacement of the high-temperature shear zone by the brittle STDS. Our data are compatible with the deformation patterns predicted for the top part of a southward flowing midcrustal channel. Citation: Wagner, T., J. Lee, B. R. Hacker, and G. Seward (2010), Kinematics and vorticity in Kangmar Dome, southern Tibet: Testing midcrustal channel flow models for the Himalaya, Tectonics, 29, TC6011,

From 2006 to 2014, Texas Parks and Wildlife Department (TPWD) personnel collected size and maturity data from female blue crabs Callinectes sapidus in all bays along the Texas coast as part of a routine fishery‐independent monitoring program. Logistic regression revealed that coastwide size at maturity was negatively impacted by salinity but that temperature had no effect. More specifically, the model estimated that coastwide size at 50% maturity was 130.5 mm at 0‰, 124.4 mm (122.7–126.0) at 10‰, 118.2 mm (117.1–119.3) at 20‰, and 112.1 mm (110.6–113.5) at 30‰. Size at maturity was found to vary substantially among bay systems in addition to the impact of environmental variables on this relationship. Finally, the logistic curve for size at maturity was found to significantly differ from a similar study (conducted by TPWD personnel; 1984 to 1987) due to higher proportions of mature crabs at smaller size‐classes in the 2006 to 2014 data set. This had a small effect on the size at 50% maturity metric, which was found to have decreased 4 mm between these two eras. Regardless of the driver behind these trends, the present analysis and explicit comparison of these results to a previous study suggests that blue crabs along the Texas coast are highly plastic in terms of size at maturity, especially spatially. Coupled with decadal declines in blue crab populations, these results may justify conservative regulation by state management agencies in terms of female spawner protection. Received December 21, 2015; accepted April 26, 2016 Published online August 12, 2016

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