Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin

first_imgMajor- and trace-element (XRF and INAA) and Nd-isotope analyses are presented on a Jurassic bimodal association of basic greenstones and silicic metavolcanic rocks from the Black Coast, northeast Palmer Land, Antarctic Peninsula. The greenstones are divided into three sub-groups, indistinct in the field, but which have geochemical characteristics of island arc tholeiites (group I), E-type MORB (group II), and continental arc basalts (group III). The tholeiites of group I and II have a similar range of ϵNd values (+3.7 to −1.2) and were produced from a heterogeneous, large ion lithophile element (LILE)-enriched, mantle source. The rocks of group III show a much stronger enrichment in LILE than groups I and II, and were derived from a mantle source with slightly lower ϵNd values (−2.3 to −5.0). The silicic volcanic rocks have low ϵNd values (−7.1 to −8.7) indicating a dominant crustal source, although trace element concentrations show a within-plate affinity. The origin and tectonic setting of this bimodal suite is discussed in relation to Mesozoic subduction along the proto-Pacific margin of the Antarctic Peninsula and southern South America and intra-continental extension associated with the break-up of Gondwana. It is concluded that the mafic greenstones and silicic metavolcanic rocks formed in an ensialic back-arc basin setting where, during a period of continental lithospheric attenuation, the rise of a mantle diapir may have caused widespread bimodal magmatism. The geographical extent of the Palmer Land basin is unknown at present, but it may be part of a much larger Weddell Sea or proto-Weddell Sea back-arc basin system.last_img read more

"Bimodal magmatism in northeast Palmer Land, Antarctic Peninsula: Geochemical evidence for a Jurassic ensialic back-arc basin"

Mapping climate change in European temperature distributions

first_imgClimate change poses challenges for decision makers across society, not just in preparing for the climate of the future but even when planning for the climate of the present day. When making climate sensitive decisions, policy makers and adaptation planners would benefit from information on local scales and for user-specific quantiles (e.g. the hottest/coldest 5% of days) and thresholds (e.g. days above 28 ° C), not just mean changes. Here, we translate observations of weather into observations of climate change, providing maps of the changing shape of climatic temperature distributions across Europe since 1950. The provision of such information from observations is valuable to support decisions designed to be robust in today’s climate, while also providing data against which climate forecasting methods can be judged and interpreted. The general statement that the hottest summer days are warming faster than the coolest is made decision relevant by exposing how the regions of greatest warming are quantile and threshold dependent. In a band from Northern France to Denmark, where the response is greatest, the hottest days in the temperature distribution have seen changes of at least 2 ° C, over four times the global mean change over the same period. In winter the coldest nights are warming fastest, particularly in Scandinavia.last_img read more

"Mapping climate change in European temperature distributions"

Recent oceanic changes in the Arctic in the context of long-term observations

first_imgThis synthesis study assesses recent changes of Arctic Ocean physical parameters using a unique collection of observations from the 2000s and places them in the context of long-term climate trends and variability. Our analysis demonstrates that the 2000s were an exceptional decade with extraordinary upper Arctic Ocean freshening and intermediate Atlantic Water warming. We note that the Arctic Ocean is characterized by large amplitude multi-decadal variability in addition to a long-term trend, making the link of observed changes to climate drivers problematic. However, the exceptional magnitude of recent high-latitude changes (not only oceanic, but also ice and atmospheric) strongly suggests that these recent changes signify a potentially irreversible shift of the Arctic Ocean to a new climate state. These changes have important implications for the Arctic Ocean’s marine ecosystem, especially those components that are dependent on sea ice or that have temperature-dependent sensitivities or thresholds. Addressing these and other questions requires a carefully orchestrated combination of sustained multidisciplinary observations and advanced modeling.last_img read more

"Recent oceanic changes in the Arctic in the context of long-term observations"

A new bathymetric compilation for the South Orkney Islands, Antarctic Peninsula (49°-39°W to 64°-59°S): insights into the glacial development of the continental shelf

first_imgWe present a new, high resolution (300 m) bathymetric grid of the continental shelf surrounding the South Orkney Islands, northeast of the Antarctic Peninsula. The new grid, derived from a compilation of marine echo-sounding data, improves previous regional bathymetric representations and helps to visualize the morphology of the shelf in unrivalled detail. The compilation forms important baseline information for a range of scientific applications and end users including oceanographers, glacial modelers, biologists, and geologists. In particular, due to the limited understanding of glacial history in this region, the bathymetry provides the first detailed insights into past glacial regimes. The continental shelf is dominated by seven glacially eroded troughs, marking the pathways of glacial outlets that once drained a former ice cap centered on the South Orkney Islands. During previous glacial periods, grounded ice extended to the shelf edge north of the islands. A large, ∼250 km long sediment depocenter, interpreted as a maximum former ice limit of one or more Cenozoic glaciations, suggests that ice was only grounded to the ∼300–350 m contour in the south. Hypsometric analyses support this interpretation, indicating that a significant proportion of the shelf has been unaffected by glacial erosion. Using these observations, we propose a preliminary ice cap reconstruction for maximum glaciation of the South Orkney plateau, suggesting an ice coverage of about ∼19,000 km2. The timing of maximum ice extent, number of past advances and pattern of subsequent deglaciation(s) remain uncertain and will require further targeted marine geological and geophysical investigations to resolve.last_img read more

"A new bathymetric compilation for the South Orkney Islands, Antarctic Peninsula (49°-39°W to 64°-59°S): insights into the glacial development of the continental shelf"

Complete genome of Planococcus rifietoensis M8T, a halotolerant and potentially plant growth promoting bacterium

first_imgPlanococcus rifietoensis M8T (=DSM 15069T = ATCC BAA-790T) is a halotolerant bacterium with potential plant growth promoting properties isolated from an algal mat collected from a sulfurous spring in Campania (Italy). This paper presents the first complete genome of P. rifietoensis M8T. Genes coding for various potentially plant growth promoting properties were identified within its genome.last_img

"Complete genome of Planococcus rifietoensis M8T, a halotolerant and potentially plant growth promoting bacterium"

Tracking the spread of a passive tracer through Southern Ocean water masses

first_imgA dynamically passive inert tracer was released in the interior South Pacific Ocean at latitudes of the Antarctic Circumpolar Current. Observational cross sections of the tracer were taken over 4 consecutive years as it drifted through Drake Passage and into the Atlantic Ocean. The tracer was released within a region of high salinity relative to surrounding waters at the same density. In the absence of irreversible mixing a tracer remains at constant salinity and temperature on an isopycnal surface. To investigate the process of irreversible mixing we analysed the tracer in potential density-versus-salinity-anomaly coordinates. Observations of high tracer concentration tended to be collocated withisopycnalsalinityanomalies.Withtime,aninitiallynarrow peak in tracer concentration as a function of salinity at constant density broadened with the tracer being found at ever fresher salinities, consistent with diffusion-like behaviourinthatcoordinatesystem.Thesecondmomentofthe tracer as a function of salinity suggested an initial period of slow spreading for approximately 2 years in the Pacific, followed by more rapid spreading as the tracer entered Drake Passage and the Scotia Sea. Analysis of isopycnal salinity gradientsbasedontheArgoprogrammesuggeststhatpartof this apparent change can be explained by changes in background salinity gradients while part may be explained by the evolution of the tracer patch from a slowly growing phase wherethetracerformsfilamentstoamorerapidphasewhere the tracer mixes at 240–550m2s−1last_img read more

"Tracking the spread of a passive tracer through Southern Ocean water masses"

BYU Men’s Golf Has Season End Monday

first_imgMay 28, 2018 /Sports News – Local BYU Men’s Golf Has Season End Monday Written by FacebookTwitterLinkedInEmailSTILLWATER, Okla.-Monday, at the NCAA Men’s Golf Championships hosted by Oklahoma State University at Karsten Creek, Brigham Young’s golf squad saw its season end as they finished 35th overall.The top 15 squads advanced to the final round of stroke play and the top eight advanced to match play. These schools include host Oklahoma State, (the Cowboys are currently in first place with a net score of 1152), Duke, Texas Tech, Oklahoma, Auburn, Alabama, Texas and Texas A&M.Patrick Fishburn ended his season for the Cougars with the best overall performance on the squad as he finished 35th overall by shooting a 76 and finishing with an overall score of 293.Broc Everett of Augusta won the individual national championship, shooting a 281. Oklahoma State has the overall lead by virtue of no players on the squad shooting above 300 as team leader Matthew Wolff is shooting a 285 for the Cowboys. Bringing up the rear for Oklahoma State is Zach Bauchou and he has a respectable net score of 299.The national championship will be decided Wednesday. Tags: Broc Everett/BYU Men’s Golf/Matthew Wolff/Oklahoma State Men’s Golf/Patrick Fishburn/Zach Bauchou Brad Jameslast_img read more

"BYU Men’s Golf Has Season End Monday"

Report: Grizzlies, forward Chandler Parsons agree to separation

first_img Written by FacebookTwitterLinkedInEmailTar_Heel_Rob/iStock(MEMPHIS, Tenn.) — Chandler Parsons’ time with the Memphis Grizzlies appears to have come to an end.Citing league sources, ESPN reports the team and the 30-year-old forward agreed to separate on Sunday.The Grizzlies and Parsons’ agent will work on placing him in another team and structuring a resolution on his future, the sources told ESPN.Per his four-year, $94 million contract with Memphis, Parsons is owed $38 million, including $25.1 million for this season, according to ESPN.Copyright © 2019, ABC Radio. All rights reserved. Beau Lundcenter_img January 7, 2019 /Sports News – National Report: Grizzlies, forward Chandler Parsons agree to separationlast_img read more

"Report: Grizzlies, forward Chandler Parsons agree to separation"

Dixie State Football Routs Black Hills State; Earns 4th Straight Win

first_img FacebookTwitterLinkedInEmailST. GEORGE, Utah-Kody Wilstead had his best game of the season, completing 18 of 23 passes for 336 yards and four touchdowns as the Dixie State Trailblazers decimated Black Hills State 52-22 Saturday in Rocky Mountain Athletic Conference football action at Trailblazers Stadium.The win was the fourth in a row for the 4-1 Trailblazers, who may have hit their stride under new head coach Paul Peterson after a season-opening 36-7 loss to perennial power Colorado State-Pueblo.Wilstead also ran for 50 yards and a score on 5 carries to pace Dixie State, while his primary targets in the passing game were redshirt senior receiver Kasey Allison (4 rec, 126 yards, 2 TD’s) and junior tight end Chase Hess (4 rec, 107 yards, 2 TD’s).Defensively, redshirt freshman Conner McKay, senior defensive back Alex Lilliard, redshirt sophomore defensive lineman Dylan Hendrickson and junior defensive lineman Kyle Murray had a sack apiece for the surging Trailblazers.In defeat, redshirt freshman signal-caller Chance Eben (20 of 34, 248 yards, 2 TD’s) led the Yellow Jackets.Next Saturday, the Trailblazers host non-conference opponent Simon Fraser of British Columbia, Canada for a 7:00 pm kickoff. Dixie State returns to RMAC action October 19 at Gunnison, Colo. against the Western Colorado Mountaineers for a 1:00 pm kickoff. October 5, 2019 /Sports News – Local Dixie State Football Routs Black Hills State; Earns 4th Straight Win Brad James Tags: Alex Lilliard/Chance Eben/Chase Hess/Conner McKay/Dixie State Football/Dylan Hendrickson/Kasey Allison/Kody Wilstead/Kyle Murray/Paul Peterson/Rocky Mountain Athletic Conference/Simon Fraser/Western Colorado Written bylast_img read more

"Dixie State Football Routs Black Hills State; Earns 4th Straight Win"

Badgers Claim 80-75 Road Victory at Southern Idaho

first_img Written by February 8, 2020 /Sports News – Local Badgers Claim 80-75 Road Victory at Southern Idaho Brad James Tags: Snow Men’s basketball FacebookTwitterLinkedInEmailTWIN FALLS, Idaho (February 8, 2020) — Leading by just three points with :02 seconds remaining, Brantzen Blackner hit a pair of free throws to seal the Snow College victory on the road against Southern Idaho. The win marked the Badgers’ fourth-straight victory and solidified the team’s hold on second place in the Scenic West Athletic Conference with a two-and-a-half-game lead over Utah State Eastern in the standings.With 14:26 remaining the game, and the score tied at 49-49, the Badgers came out of a timeout to go on a 10-2 run that would create the momentum needed to hold the lead through the remainder of the game.“There’s been a lot of years where we haven’t won up here,” Snow College head coach Rob Nielson said. “It’s great for our guys to come up here and compete for the win.”Tredyn Christensen led the Badgers with 15 points on 7-of-13 shooting from the field and was credited with seven rebounds, including six offensive boards. Brayden Johnson chipped in 14 points, while Blacker and Trey Farrer had nine points each.The Badgers will return ot Ephraim on Thursday, Feb. 13 to take on Utah State Eastern. Part of the “Pack the HAC” promotion, the first 500 fans wearing orange to the game will receive a free orange creamsicle.last_img read more

"Badgers Claim 80-75 Road Victory at Southern Idaho"