bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early Cretaceous magmatism and post-Early Cretaceous deformation on Ellef Ringnes Island, Canadian High Arctic, related to the formation of the Arctic Ocean
Authors: Estrada Solveig , Piepjohn Karsten 
Published: October 2019

ABSTRACT
Ellef Ringnes Island in the western Queen Elizabeth Islands near the Canadian Polar margin is characterized by intrusions of Cretaceous mafic sills and dikes related to the Canadian portion of the High Arctic Large Igneous Province (HALIP) and the presence of a unique network of NNE–SSW and WSW–ENE striking steep faults. The exposed dikes on northern Ellef Ringnes Island are mostly oriented parallel to the NNE–SSW faults according to the radiating dike swarm of the HALIP. The studied sills and dikes are geochemically very homogeneous and probably related to the same intrusion event at ca. 121 Ma. They share geochemical similarities with other tholeiitic basaltic rocks related to the first stage of the HALIP (ca. 130–120 Ma) that are exposed on Axel Heiberg and northern Ellesmere islands. All these suites were probably generated from a common large magmatic center related to a mantle plume. The NNE–SSW striking faults are characterized by dextral strike-slip kinematics active after ca. 100 Ma (after the intrusion of the Early Cretaceous sills and dykes and the deposition of the Christopher Formation) and before the deposition of the Neogene Arctic continental terrace wedge. However, they cannot be related to the dextral strike-slip regime parallel to the continental margin during stage 2 of the Eurekan deformation in the Late Eocene. Instead, the NNE–SSW dextral faults may represent dextral antithetic Riedel faults of a wide, NE–SW striking, anastomosing strike-slip fault zone along the northern continental margin of North America, which was possibly active during Eurekan stage 1 in the Early Eocene.
Aeromagnetic high-resolution survey over the Vendom Fiord region, Ellesmere Island, Canadian High Arctic
Authors: Ruppel Antonia , Damaske Detlef , Piepjohn Karsten 
Published: October 2019

ABSTRACT
Within the Canadian High Arctic, Ellesmere Island represents a key region for improving our understanding of the plate tectonic configuration during the Paleogene times when Arctic Canada and Greenland represented two independently moving plates. Here, we present 4050 line kilometers of new high-resolution aeromagnetic data gathered across an area of 7000 km2 in the Vendom Fiord region on southern Ellesmere Island. The survey was flown with a two-kilometer line spacing and covered sedimentary rocks of the Franklinian Basin and the partly ice-covered basement rocks of the Inglefield Uplift. Magnetic domains, major lineaments, and depths of magnetic sources as well as magnetic trend lines are detected from total field data. These data and additional ground-based magnetic susceptibility measurements are integrated with exposure information and structural data in order to distinguish whether or not the ca. NNE–SSW trending Vendom Fiord Fault Zone can be related to the Wegener Fault. In addition, high-resolution aeromagnetic data and digital enhancement provide support for early Eocene deformation in the Vendom Fiord region during “Eurekan stage 1,” which seems to be decoupled from Paleocene to early Eocene deformation along the Wegener Fault.
A distinct NNE–SSW trending magnetic anomaly characterized by long wavelength is bordered by the Eurekan Fold-and-Thrust Belt in the western survey area. On a regional scale, this anomaly can be traced toward the NE where it represents the boundary between the deep water and shelf sequences of the Franklinian Basin along the Archer Fiord Fault Zone. Based on aeromagnetic anomaly data, the ice-covered boundary between sediments of the Franklinian Basin and the Precambrian basement is identified. High frequency anomalies east of this boundary characterize the basement rocks and show strong similarities to the Kane Basin region in the NE. The similarity of magnetic anomaly patterns in both regions indicates that the NNE–SSW trend of the fault zones in the study area west of the Inglefield Uplift turns continuously into an E–W trend north of the uplift in the Kane Basin region.
Structural evidence for sinistral displacement on the Wegener Fault in southern Nares Strait, Arctic Canada
Authors: von Gosen* W. , Piepjohn* K. , Gilotti* J.A. , McClelland* W.C. , Reinhardt* L. 
Published: October 2019

ABSTRACT
The sinistral Wegener Fault in the Nares Strait between northwest Greenland and eastern Ellesmere Island (Canadian Arctic) represents a tectonic element in the Arctic whose existence and significance have been controversial for more than 50 years. Some workers interpret the Wegener Fault as an important early Tertiary transform related to movement of the Greenland plate relative to the North American plate. Others view it as insignificant or reject its existence. While onshore studies in the Canadian portion of the northern Nares Strait region have proven the existence of important sinistral strike-slip faults related to the offshore Wegener Fault, the southern continuation of the Wegener Fault in the southern Kane Basin and Smith Sound is unclear. In particular, Smith Sound has been interpreted as a location of an undisturbed continuation of the Proterozoic basement from Greenland to Ellesmere Island, with only one possible location of the Wegener Fault near the east coast of Ellesmere Island.
Our structural studies along the west coast of Smith Sound and adjacent areas of eastern Ellesmere Island suggest a three-phase tectonic evolution. Phase 1 is a brittle deformation (strike-slip faults, partly as conjugate sets) that took place under ~NW–SE shortening. It also occurs at the Smith Sound coast and did not affect the Paleogene deposits. Structures of this phase are assigned to the Paleocene and can be related to the Wegener Fault in the offshore area of Smith Sound just east of the eastern coast of Ellesmere Island. Deposition of thick conglomerates of the Paleocene Cape Lawrence Formation and relatively younger clastic sediments of the Eureka Sound Group (Paleocene–?Eocene) is interpreted to be related to local depocenters associated with the sinistral Wegener Fault.
Following uplift and subsidence during normal faulting associated with Phase 2 deformation, younger contractional deformation under ~NE–SW shortening (strike-slip faults, partly as conjugate sets) of Phase 3 deformation also affected the Paleogene deposits. Phases 2 and 3 can both be assigned to the Eocene.
Our interpretation points to a polyphase deformational history in the early Paleogene, which partly interfered with deposition of Paleogene clastic sediments. The first deformational phase in the Paleocene is related to the sinistral Wegener Fault, which, in the offshore areas, is not interpreted as a distinct through-going plane but as displaced by ~W–E striking faults. Therefore, our observation and interpretation support the existence of this fault in the southern Nares Strait region, east of the Ellesmere Island coast in Smith Sound.
Detrital zircon U-Pb geochronological and Hf isotopic constraints on the geological evolution of North Yukon
Authors: Colpron* Maurice , McClelland* William C. , Strauss* Justin V. 
Published: October 2019

ABSTRACT
North Yukon lies at the intersection of two major tectonic domains that define the western and northern edges of the North American continent—the northern Cordilleran mountain belt and the Arctic Ocean. The pre-Carboniferous geology in North Yukon includes the Neoproterozoic−lower Paleozoic North Slope subterrane of the Arctic Alaska terrane and, south of the Porcupine shear zone, Mesoproterozoic−Paleozoic rocks of the Yukon stable block. The North Slope subterrane was deformed prior to deposition of Carboniferous and younger strata, and its paleogeographic origins are debated. North Yukon was deformed again during Cretaceous−Cenozoic development of the northern Cordilleran−Brookian orogen.
To help refine understanding of the geological evolution of the region, we present detrital zircon U-Pb and Hf isotopic data for 21 sandstone and conglomerate samples from Neoproterozoic to Cenozoic strata collected across North Yukon, between ~69°15′N and 67°11′N. Neoproterozoic−Cambrian strata in the British Mountains are characterized by a dominance of Paleoproterozoic zircons (peak at 1.7–1.8 Ga), whereas samples from the Barn Mountains to the south have abundant Mesoproterozoic grains (1.0–1.5 Ga), suggesting these rocks may have been deposited along different segments of the northern Laurentian margin. Regional geophysics suggest these domains could be separated by a fault. Northeastern Laurentian origins are indicated by distinct early Neoproterozoic and Ordovician−Silurian zircons in Upper Silurian−Lower Devonian immature sandstone and conglomerate of the Clarence River Group and provide the most compelling evidence for large-scale translation along northern Laurentia.
Precambrian detrital zircons in Carboniferous and younger strata reflect mostly recycling of local older strata. Carboniferous conglomerates all show Late Devonian peaks (365–378 Ma) consistent with erosion of nearby granitoid plutons. Triassic to Paleocene samples yielded a range of Neoproterozoic−Paleozoic zircons recycled from nearby Devonian flysch. Most significantly, these samples also yielded juvenile zircons that are close to depositional age, but for which arc sources are only known in southern Yukon and Alaska, more than 700 km away. These source regions are distinct from NE Russian sources inferred for early Brookian (Early Cretaceous) foreland deposits in Alaska.
Pre-Mississippian stratigraphy and provenance of the North Slope subterrane of Arctic Alaska I: Platformal carbonate rocks of the northeastern Brooks Range and their signifi cance in circum-Arctic evolution
Authors: Strauss Justin V. , Macdonald Francis A. , McClelland William C. 
Published: October 2019

ABSTRACT
The Neoproterozoic–Early Devonian platformal succession of the North Slope subterrane, northeastern Brooks Range, Alaska, represents a carbonate-dominated peri-Laurentian continental fragment within the composite Arctic Alaska–Chukotka microplate. The basal ca. 760–720 Ma Mount Weller Group consists of an ~400 m thick mixed siliciclastic and carbonate succession that records the onset of regional extensional tectonism associated with the separation of southeastern Siberia from northern Laurentia during the break-up of Rodinia. These strata are overlain by ca. 720 Ma continental flood basalts of the Kikiktat volcanic rocks, which provide a link between the northeast Brooks Range platformal succession and the ca. 723–717 Ma Franklin large igneous province (LIP) of northern Laurentia. The overlying Sturtian Hula Hula diamictite and Cryogenian–Ediacaran Katakturuk Dolomite record abbreviated thermal subsidence of the northeast Brooks Range platformal succession prior to renewed Ediacaran–early Cambrian extensional tectonism and deposition of the overlying lower Paleozoic Nanook Group (new name). Equivalent strata of the deep-water Cryogenian–lower Cambrian(?) Ikiakpuk Group (new name) are identified herein with new δ13Ccarb and 87Sr/86Sr isotopic data from the Fourth Range of the northeastern Brooks Range. The Nanook Group is formally divided herein into the Black Dog and Sunset Pass formations, which record isolated peri-Laurentian platformal carbonate sedimentation along the northern margin of Laurentia, in an analogous tectonic position to the modern Bahama Banks. A profound Late Ordovician(?)-Early Devonian unconformity within the platformal succession is marked by subaerial exposure, paleokarst development, and tilting of the northeast Brooks Range peri-Laurentian platformal fragment prior to deposition of the overlying Lower Devonian Mount Copleston Limestone.
Unravelling the thermal evolution of the Neruokpuk Formation in the British Mountains, North Yukon, Canada: Tectonic and orogenic implications
Authors: Bigot-Buschendorf Maelianna , Mouthereau Frédéric , Labrousse Loïc , Fillon* Charlotte , Stübner Konstanze , Bernet Matthias 
Published: October 2019

ABSTRACT
Defining temporal and spatial distribution of shortening is critical to reconstruct past plate motions and to examine mechanical coupling processes at convergent plate boundaries. Understanding the collisional evolution of the British Mountains and Beaufort-MacKenzie basin in the northern Alaska–Yukon region is key for the geodynamics of the Arctic region. With the aim to resolve the exhumation history of this region, we present the first zircon fission-track and (U-Th)/He analyses on apatite and zircon from the Neruokpuk Formation (ca. 720–485 Ma), which forms the orogenic basement of the British Mountains. Zircon fission-track ages show partial resetting, indicating the Proterozoic basement did not reside at temperatures above 240 °C. Thermal modeling of zircon and apatite (U-Th)/He data indicates that our samples reached this maximum temperature at ca. 100 Ma. The onset of the Brookian collision is indicated by exhumation from ca. 80 Ma. A total exhumation of 7–8.5 km since the Late Cretaceous is inferred. Apatite (U-Th)/He ages of ca. 50 Ma show that exhumation was less than 2.5 km since the early Eocene. We infer from a comparison with the temporal evolution of exhumation from adjacent orogenic domains that shortening progressively shifted northward from the British Mountains to the Barn Mountains and offshore in the Beaufort Sea during the Paleocene. Along-strike variations in the architecture of the rifted margin of Arctic Alaska is suggested to have exerted a strong control on the structural styles and observed exhumation patterns.
Numerical groundwater models for Edwards Aquifer systems
Authors: Green R.T. , Winterle J. , Fratesi B. 
Published: October 2019

ABSTRACT
Numerical models have been an integral component in management of the Edwards Aquifer for over four decades. The scale and complexity of the models have varied considerably during this time, with the changes attributed to improvements in both numerical software and the conceptual models on which the models are predicated. Resolution of early models was coarse, which rendered them useful only in large-scale, groundwater-resource assessments. Increased resolution and improved refinement in the conceptualization of the complex hydrostratigraphic framework of the Edwards Aquifer have led to expanded applicability of the ensuing models in terms of accommodating local-scale hydraulic features such as pumping scenarios and changes in recharge/discharge mechanisms (i.e., urbanization and climate change). As part of these improvements and advancements, regional-scale groundwater availability models augmented by local-scale models based upon improved conceptualization provide the ability to: (1) replicate more extreme conditions, such as the drought-of-record; (2) improve boundary conditions by extending models to include natural hydraulic boundaries; and (3) couple groundwater flow models with surface-water flow models so that the entire terrestrial water cycle can be accommodated during water-resource management scenario assessment.
Biology and ecology of the Edwards Aquifer
Authors: Krejca* Jean , Reddell† James 
Published: October 2019

ABSTRACT
The Edwards Aquifer supports an important ecosystem with rarely seen faunas that have unique adaptations to a dark and thermally stable environment. We tallied over 60 species of aquifer-adapted (stygobitic) species in the Edwards Aquifer, and 30 more in other Texas aquifers, including snails, flatworms, worms, crustaceans, mites, and beetles. Exploration and research continue, with nine new species described in the last two years. Vertebrate species include Eurycea salamanders and ictalurid catfish, including a blind species (Prietella phreatophila) recorded for the first time in the United States from the Edwards–Trinity Plateau Aquifer in 2016. Contributing to the stygobite diversity are ten state or federally listed species, including the Texas blind salamander (Eurycea rathbuni), which was one of the first species to be listed as endangered by the U.S. Fish and Wildlife Service (USFWS) in 1970. Major springs of the Edwards (Balcones fault zone), Edwards–Trinity Plateau, Trinity, and other aquifers are under constant threat of drying due to aquifer overdraft and climate change. These springs provide habitat for 26 state or federally listed spring-adapted species. Aquifer species in general are known to provide ecosystem services, including water purification, nutrient cycling, and biological indication; however, the function and biology of these species in central Texas have not been studied. Considering the Edwards Aquifer ranks among the top aquifers in the world for number of species, the gaps in understanding remain enormous.
Geologic structure of the Edwards (Balcones Fault Zone) Aquifer
Authors: Ferrill David A. , Morris Alan P. , McGinnis Ronald N. 
Published: October 2019

ABSTRACT
The Edwards (Balcones Fault Zone) Aquifer is structurally controlled by the system of normal faults following the Balcones Escarpment, with major domains, including contributing, recharge (unconfined), and artesian (confined) zones, dictated by the large-displacement (50 m to &gt;250 m throw) normal faults and depth of erosion. Faults and extension fractures, in many cases enhanced by dissolution, localize recharge and flow within the Balcones fault zone and into the subsurface of the artesian zone. Juxtaposition of the Edwards with other aquifers provides avenues for interaquifer communication, while juxtaposition against impermeable layers and concentration of clay and mineralization along faults locally produce fault seals for compartmentalization and confinement. Fault block deformation, including small faults and extension fractures, leads to aquifer permeability anisotropy. Faults also locally provide natural pathways for groundwater discharge through springs above the confined (artesian) zone. Although the importance of joints and faults in the Edwards (Balcones Fault Zone) Aquifer system is recognized, there has not been a systematic analysis of the meter-scale structures in the Edwards and associated confining units and their influence on groundwater flow. Here, we review evidence from several key areas showing that an analysis of faults and fractures in the Edwards (Balcones Fault Zone) Aquifer and associated aquifers and confining units is needed to characterize structural fabrics and assess the permeability architecture critical for the next generation of groundwater modeling of the aquifer.
The Edwards Aquifer Habitat Conservation Plan: Its planning and implementation
Authors: Payne Shaun , Pence Nathan , Furl Chad 
Published: October 2019

ABSTRACT
The Edwards Aquifer Habitat Conservation Plan (EAHCP) protects the federally listed species in the Comal and San Marcos Springs. The plan was developed through the Edwards Aquifer Recovery Implementation Program, a consensus-based process involving a diverse body of stakeholders including industries, agricultural users, municipalities, water purveyors, river authorities, environmental organizations, four state agencies, and downstream interests. Since 2013, the partners of the EAHCP have implemented a multifaceted program mainly focused on spring-flow protection and habitat improvements to ensure the persistence of the covered species and to create more certainty in the region’s water supplies.
The use of water from the Edwards Aquifers, Texas
Authors: Mace* Robert E. 
Published: October 2019

ABSTRACT
Both people and the environment require water. The environment in Texas depends upon water discharged from the Edwards Aquifers, including ~1.5 million megaliters per year (ML/yr) from the Edwards-Trinity (Plateau) Aquifer and ~1 million ML/yr from the Edwards (Balcones Fault Zone) Aquifer. The first people in the area used the aquifer springs as drinking water and subsequently irrigated with the springs’ flow and then began drilling and pumping wells. Well production in the Edwards (Balcones Fault Zone) Aquifer was ~120,000 ML/yr in the 1930s and steadily increased over the next three decades to ~500,000 ML/yr, which is the average use from 1970 to 2015. Production from the Edwards-Trinity (Plateau) Aquifer was ~250,000 ML/yr from 1984 through 2016, while production from the Edwards-Trinity (High Plains) Aquifer was ~25,000 ML/yr from 1984 through 2016. The Interstate 35 growth corridor, extending from Bexar County (San Antonio) through New Braunfels, San Marcos, and Austin, Texas, and up to Bell County, is expected to grow from 4.6 million people in 2020 to 8.7 million in 2070. Despite the needs of this growing population, groundwater availability and regional water planning information suggests that pumping from the Edwards (Balcones Fault Zone) Aquifer over the next 50 yr will be limited. Groundwater availability numbers suggest that pumping in the Edwards-Trinity (Plateau) Aquifer could double from current levels, although planning information currently projects a more modest increase. Unsettled groundwater law and climate change could also affect future levels of pumping.
Evidence for the sinistral Porcupine shear zone in North Yukon (Canadian Arctic) and geotectonic implications
Authors: von Gosen* W. , Piepjohn* K. , McClelland* W.C. , Colpron* M. 
Published: October 2019

ABSTRACT
Structural analysis of Neoproterozoic to lower Paleozoic rocks near Old Crow, in North Yukon, show that they were affected by widespread, but distributed sinistral shear zone deformation. This tectonic event occurred under brittle-ductile conditions, in the early Paleozoic, prior to intrusion of Late Devonian granitoids of the Old Crow plutonic suite (368–375 Ma). Although outcrops are scattered, the shear zone deformation can be inferred to extend over a broad ~W–E corridor, ~10–20 km-wide and ~145 km long, from eastern Alaska into northern Yukon. The sinistral Porcupine shear zone is interpreted to represent a major, early Paleozoic crustal structure along which elements of NE Laurentian and Caledonian affinities in the Arctic Alaska terrane were transferred across the Arctic region during the Paleozoic. Our observations do not support major Paleogene dextral strike-slip deformation along the Porcupine River near Old Crow.
Synsedimentary deformation in Upper Cretaceous–Lower Paleogene limestones within a thrust anticline of the Umbria-Marche Apennines, Italy
Authors: Tognaccini Sofia , Tavarnelli Enrico , Montanari Alessandro 
Published: October 2019

ABSTRACT
The geometry of collisional mountain belts, which were formed at the expense of passive continental margins, is often complex because orogenic structures, such as thrusts and related folds, commonly interfere with pre-orogenic extensional structures, namely, normal faults, resulting in kinematically complex, composite structural assemblages. In these settings, analysis of the relationships between depositional and structural features may provide very useful tools to correctly unravel the local sedimentary and deformational history and relative ages of structures. Analysis of the relationships between minor normal faults and slumps near Frontale in the Umbria-Marche Apennines of Italy made it possible to correctly unravel the local chronology of events and hence to infer the depositional and deformation history of a part of the Upper Cretaceous–Paleogene Scaglia Rossa Formation pelagic basin. The results of this investigation made it possible to ascribe the normal faults to events that predate the construction of the Umbria-Marche mountain belt. Therefore, the normal faults at Frontale are distinct from those that overprint the main compressional structures responsible for the present-day seismicity of central Italy.