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The oxygen isotope composition, petrology and geochemistry of mare basalts: Evidence for large-scale compositional variation in the lunar mantle

first_imgTo investigate the formation and early evolution of the lunar mantle and crust we have analysed the oxygen isotopic composition, titanium content and modal mineralogy of a suite of lunar basalts. Our sample set included eight low-Ti basalts from the Apollo 12 and 15 collections, and 12 high-Ti basalts from Apollo 11 and 17 collections. In addition, we have determined the oxygen isotopic composition of an Apollo 15 KREEP (K – potassium, REE – Rare Earth Element, and P – phosphorus) basalt (sample 15386) and an Apollo 14 feldspathic mare basalt (sample 14053). Our data display a continuum in bulk-rock delta O-18 values, from relatively low values in the most Ti-rich samples to higher values in the Ti-poor samples, with the Apollo 11 sample suite partially bridging the gap. Calculation of bulk-rock delta O-18 values, using a combination of previously published oxygen isotope data on mineral separates from lunar basalts, and modal mineralogy (determined in this study), match with the measured bulk-rock delta O-18 values. This demonstrates that differences in mineral modal assemblage produce differences in mare basalt delta O-18 bulk-rock values. Differences between the low- and high-Ti mare basalts appear to be largely a reflection of mantle-source heterogeneities, and in particular, the highly variable distribution of ilmenite within the lunar mantle. Bulk delta O-18 variation in mare basalts is also controlled by fractional crystallisation of a few key mineral phases. Thus, ilmenite fractionation is important in the case of high-Ti Apollo 17 samples, whereas olivine plays a more dominant role for the low-Ti Apollo 12 samples. Consistent with the results of previous studies, our data reveal no detectable difference between the Delta O-17 of the Earth and Moon. The fact that oxygen three-isotope studies have been unable to detect a measurable difference at such high precisions reinforces doubts about the giant impact hypothesis as presently formulated.last_img read more


May 9, 2021 0

Basal and field metabolic rates of Streaked Shearwater during the chick-rearing period

first_imgThe energetics of adult Streaked Shearwaters Calonectris leucomelas during the chick-rearing period were examined on Awa Island, Japan, in 2008 and 2009. Basal metabolic rates (BMR) were quantified using an open-flow respirometry system and field metabolic rates (FMR) were quantified using a doubly labelled water (DLW) method. In addition, we used activity loggers to estimate time allocations for different activities at sea. BMR was 0.0124 kJ g(-1) h(-1) (+/- 0.0153, N=4) on average and corresponded to 54% of the value predicted from allometric equations. FMR was 0.0634 kJ g(-1) h(-1) (+/- 0.0331, N=3) and was equivalent to 5.1 times BMR, which was higher than values reported for albatrosses (2-4 times BMR). Shearwaters made 50.3 landings a day (+/- 9.8, N=12) and spent 44.8% (+/- 8.0, N=12) of their time sitting on the water. They landed on water approximately twice as often as albatrosses (which have been well-studied using DLW), but they both spent similar proportions of their time on water. Frequent landings at sea, and frequent takeoffs, may generate incremental energetic expenses because of the use of flapping flight; therefore, the Streaked Shearwater’s relatively high FMR may be related to its high number of landings.last_img read more


May 9, 2021 0

Genetic data support independent glacial refugia and open ocean barriers to dispersal for the Southern Ocean sea spider Austropallene cornigera (Möbius, 1902)

first_imgThe diversity and distribution of Antarctic life has been strongly influenced by climatic events, in particular by large scale extension of ice sheets onto the continental shelf during repeated glacial cycles. It has been suggested that populations of benthic marine biota in the Antarctic were limited to very few refugia because the Antarctic shelf was covered with ice. Using the broadly-distributed pycnogonid Austropallene cornigeraas a model, in this study we tested different hypotheses for possible locations of glacial refugia ( ex situon the peri-Antarctic islands or in situon the Antarctic shelf). We sampled 64 individuals of A. cornigerafrom peri-Antarctic islands, the Weddell Sea and East Antarctica. The phylogeographic structure was analysed using partial sequences of the nuclear ribolomal genes 18S and 28S and the mitochondrial cytochrome coxidase subunit I gene (COI). The 18S and 28S sequences were highly conserved. Sequences of the COI were variable and revealed highest haplotype diversity for populations on the Antarctic shelf and lowest for the population from the remote island of Bouvetøya. In addition, the data showed clear genetic distances between the island and shelf populations. Our data are consistent with the hypothesis of survival in situ. The results also suggest that gene flow within A. cornigerais limited, hinting at possible speciation processes acting independently on the Antarctic continental shelf and the peri-Antarctic islands.last_img read more


May 9, 2021 0

Paleocirculation and ventilation history of Southern Ocean sourced deep water masses during the last 800,000 years

first_imgMost conceptual models of ocean circulation during past glacial periods invoke a shallowed North Atlantic‐sourced water mass overlying an expanded, poorly ventilated Southern Ocean (SO)‐sourced deep water mass (Southern Component Water, or SCW), rich in remineralised carbon, within the Atlantic basin. However, the ventilation state, carbon inventory and circulation pathway of SCW sourced in the Pacific sector of the SO (Pacific SO) during glacial periods are less well understood. Here, we present multi‐proxy data – including δ18O and δ13C measured on the benthic and planktic foraminifera Cibicidoides wuellerstorfi, and Neogloboquadrina pachyderma, and productivity proxies including percent CaCO3, total organic carbon (TOC) and Ba/Ti – from a sediment core located in the high latitude (71°S) Pacific SO spanning the last 800 kyr. Typical glacial δ13C values of SCW at this core site are ~0 ‰. We find no evidence for SCW with extremely low δ13C values during glacials in the high latitude Pacific SO. This leads to a spatial gradient in the stable carbon isotope composition of SCW from the high latitude SO, suggesting there are different processes of deep‐ and bottom‐water formation around Antarctica. A reduced imprint of air‐sea gas exchange is evident in the SCW formed in the Atlantic SO compared with the Pacific SO. A spatial δ13C gradient in SCW is apparent throughout much of the last 800,000 years, including interglacials. A SO‐wide depletion in benthic δ13C is observed is early MIS 16, coinciding with the lowest atmospheric pCO2 recorded in Antarctic ice cores.last_img read more


May 9, 2021 0

New information on the skull roof of Protoichthyosaurus (Reptilia: Ichthyosauria) and intraspecific variation in some dermal skull elements

first_imgA previously unrecognized specimen of Protoichthyosaurus prostaxalis, LEICT G142.1991, from the Lower Jurassic of Barrow-upon-Soar, Leicestershire, UK, includes an almost complete three-dimensional skull that provides new information on the configuration of the skull roof. The position of the pineal foramen (between the frontals and the parietals) and an elongated internasal foramen in a depression along the midline of the nasals are clearly shown. The maxilla makes up a significant portion of the external naris ventral margin, an unusual character for the genus/species. This reflects intraspecific variation, not evidence of a new taxon. The specimen enables comparisons of skull roof morphology with Ichthyosaurus and Stenopterygius, two common Early Jurassic taxa. In particular, the position of the pineal foramen is similar to Stenopterygius, but distinguishes Protoichthyosaurus from Ichthyosaurus. The lack of a frontal–prefrontal contact and the posteriorly wide nasals distinguishes Protoichthyosaurus from Stenopterygius. We also present a revised reconstruction of the skull roof morphology of Ichthyosaurus. Three additional specimens of Protoichthyosaurus are referred to the genus: another partial skull, referred to P. prostaxalis, and two isolated forefins, identified by their unique morphology.last_img read more


May 9, 2021 0

Dillon Maggard Places 13th at USATF Championships

first_imgJune 25, 2018 /Sports News – Local Dillon Maggard Places 13th at USATF Championships FacebookTwitterLinkedInEmailDES MOINES, Iowa-Sunday, the decorated and legendary Utah State track and field/cross country athlete Dillon Maggard concluded his Aggies career by placing 13th in the men’s 5000-meter run at the USATF Championships at Drake University.Maggard’s time of 13:55.06 saw him hang with the top group in the race until the final 1,000 meters when he began to tail off.The Kirkland, Wash. native concludes his Aggies career having been a 9-time All-American while competing in both track and field and cross country for Utah State.This race was won by Paul Chelimo of the U.S. Army in a time of 13:29.47. Tags: Dillon Maggard/Paul Chelimo/USATF Championships/USU Track and Field/Cross Country Brad James Written bylast_img read more


May 8, 2021 0

Scoreboard roundup — 8/10/18

first_img FacebookTwitterLinkedInEmailiStock/Thinkstock(NEW YORK) — Here are the scores from Friday’s sports events:INTERLEAGUESt. Louis 7, Kansas City 0AMERICAN LEAGUETexas 12, N.Y. Yankees 7Boston 19, Baltimore 12Tampa Bay 7, Toronto 0Detroit 5, Minnesota 3Seattle 5, Houston 2Chicago White Sox 1, Cleveland 0L.A. Angels 4, Oakland 3NATIONAL LEAGUEChicago Cubs 3, Washington 2Cincinnati 3, Arizona 0N.Y. Mets 6, Miami 2Atlanta 10, Milwaukee 1Colorado 5, L.A. Dodgers 4San Diego 2, Philadelphia 0San Francisco 13, Pittsburgh 10WOMEN’S NATIONAL BASKETBALL ASSOCIATIONChicago 97, Connecticut 86Phoenix 94, Indiana 74NATIONAL FOOTBALL LEAGUE PRESEASONN.Y. Jets 17, Atlanta 0Oakland 16, Detroit 10Copyright © 2018, ABC Radio. All rights reserved. August 11, 2018 /Sports News – National Scoreboard roundup — 8/10/18 Written bycenter_img Beau Lundlast_img read more


May 8, 2021 0

Red Sox arrive in Boston with World Series trophy

first_img FacebookTwitterLinkedInEmailMichael Swensen for The Boston Globe via Getty Images(BOSTON) — The Boston Red Sox are back home after defeating the Los Angeles Dodgers in five games to become the World Series champions.The team arrived at Fenway Park, along with their championship trophy, Monday night, and were greeted by fans and camera crews, ESPN reports.The Red Sox beat the Dodgers 5-1 in Game 5 of the World Series Sunday night to clinch the title — the team’s fourth since 2004.A championship parade will be held for the Red Sox in Boston Wednesday morning.Copyright © 2018, ABC Radio. All rights reserved. Beau Lund Written bycenter_img October 30, 2018 /Sports News – National Red Sox arrive in Boston with World Series trophylast_img read more


May 8, 2021 0

Clemson overpowers Alabama in championship game, wins 44-16

first_img Written by January 8, 2019 /Sports News – National Clemson overpowers Alabama in championship game, wins 44-16 Beau Lundcenter_img FacebookTwitterLinkedInEmailPhil Ellsworth / ESPN Images(SANTA CLARA, Calif.) — The Clemson Tigers dominated the Alabama Crimson Tide in Monday night’s College Football Playoff National Championship game. Clemson beat Alabama 44-16 to take home its second national championship in the past three seasons. Alabama, ranked No. 1, had been the favorite to win.With the victory, Clemson finished its season 15-0, becoming the first Division I/FBS team to end with a perfect record since Penn in 1897, according to ESPN.The Tigers will celebrate their win at home on Saturday with a victory parade beginning at 9 a.m. ET followed by a celebration at Clemson Memorial Stadium at 10:30 a.m.Copyright © 2019, ABC Radio. All rights reserved.last_img read more


May 8, 2021 0

Texas leather company scores with baseball gloves that are made by hand in the US

first_img Written by April 5, 2019 /Sports News – National Texas leather company scores with baseball gloves that are made by hand in the US FacebookTwitterLinkedInEmailABC News(NORCONA, Texas) — For four generations, a company in tiny Nocona, Texas, has been stitching baseball gloves by hand for America’s greatest players — and it has no plans on letting up.Nokona Leather Goods was started in 1926 by Executive Vice President Rob Storey’s grandfather, Robert “Big Bob” Storey.A local banker, he started the company as a wallet-and-purse factory. When the Great Depression settled in, however, he began looking for a different focus to keep his leather company alive.In 1934, Storey’s grandfather, who had also played baseball at Rice University in Texas, made the company’s first baseball glove. That’s when Nokona Ball Gloves was born.The company, which now employs 50 workers, makes 150 baseball gloves a day. The gloves are worn by players on the Pittsburgh Pirates and Minnesota Twins, as well as the Kansas City Royals.“My grandfather in the ’60s kinda set the tone for the company in that we weren’t going to go overseas to produce gloves. We weren’t going to chase the cheapest dollar, the cheapest labor, because we’re in a small town here in Texas,” Storey told ABC News. “It’s very important to us that we’re part of the local community and that we use American labor.”The domestic leathers that the company gets predominantly come from Texas, Kansas, Oklahoma and Nebraska. The domestic leathers are tanned in Milwaukee and Chicago, where most of the old tanneries originated, according to Storey.“We’re always striving to use the best possible leather to make the best possible glove for the fit that we need,” Storey said.Gloves start at around $225.Storey said that having U.S. workers were a “big advantage for us because we can use labor and use people that know how to make a glove but also know something about the game. … With a Nokona glove, it’s made by an American and somebody that can go and see a game at night.”The company is also a family affair for some workers.“Each one of these people who work here puts everything they have into this job, everything they have into each baseball glove — and you can’t ask for better,” said Josh Yeargin, who works in shipping and receiving and whose mother, Carla Yeargin, also works at Nokona. “Having players out there using our gloves. I mean, that’s just amazing.”Employee Brandy Claxton said customers were often surprised that the company made the baseball mitts by hand.“We have a lot of TLC into our gloves. We’re not machine-made products — we have people that are actually sitting in the chairs. They touch every glove that comes through and that makes it personal,” Claxton said. “To see the American flag on the glove, on the side of the glove, and even stamped on the palm. It makes them very proud. You don’t see a lot of products that are made in America anymore.”Jeff Beraznik, Nokona’s president, said the quality and attention to detail made the company’s gloves different.“We can make good business decisions and make sure that Nokona is in a solid financial position for the future and a big part of that is that secret weapon of being made in America,” Beraznik said.Copyright © 2019, ABC Radio. All rights reserved.center_img Beau Lundlast_img read more


May 8, 2021 0