Sedimentology and structure of the trench-slope to forearc basin transition in the Mesozoic of Alexander Island, Antarctica

first_imgThe Mesozoic forearc of Alexander Island, Antarctica, is one of the few places in the world where the original stratigraphic relationship between a forearc basin and an accretionary complex is exposed. Newlydiscovered sedimentary rocks exposed at the western edge of the forearc basin fill (the Kimmeridgian–Albian Fossil Bluff Group) record the events associated with the basin formation. These strata are assigned to the newly defined Selene Nunatak Formation (?Bathonian) and Atoll Nunataks Formation (?Bathonian-Tithonian) within the Fossil Bluff Group.The Selene Nunatak Formation contains variable thicknesses of conglomeratesand sandstones, predominantly derived from the LeMay Group accretionary complex upon which it is unconformable. The formation marks emergence and subsequent erosion of the inner forearc area. It is conformably overlain by the1 km thick Atoll Nunataks Formation, characterized by thinly-bedded mudstones and silty mudstones representing a marine transgression followed by trench-slope deposition. The Atoll Nunataks Formation marks a phase of subsidence, possibly in response to tectonic events in the accretionary prism that are known to have occurred at about the same time.The Atoll Nunataks Formation is conformably overlain by the Himalia Ridge Formation, a thick sequence of basin-wide arc-derived conglomerates. This transition from fine- to coarse-grained deposition suggests that a well-developed depositional trough (and hence trench-slope break) had formed by that time. The Atoll Nunataks Formation therefore spans the formation of the forearc basin, and marks the transition from trench-slope to forearc basin deposition.last_img read more

The role of upstream ULF waves in the generation of quasi-periodic ELF-VLF emissions

first_imgRecent work suggests that the quasi-periodic (QP) modulation ~10–50 s of naturally occurring ELF-VLF radio emissions (~0.5–5 kHz) is produced by the compressional action of Pc3 magnetic pulsations on the source of the emissions. Whilst it is generally accepted that these magnetic pulsations have an exogenic source, it is not clear what the mechanism of their generation is. A study of QP emissions observed during 1988 at Halley, Antarctica, in conjunction with IMP-8 satellite solar wind data, shows that the occurrence and modulation frequency of the emissions are strongly dependent upon the direction and strength of the IMF, respectively. The observed relationships are very similar to those previously reported for Pc3 pulsations associated with upstream ion-cyclotron resonance, involving proton beams reflected at the bowshock. In comparing the observed QP modulation frequencies with upstream wave theory, agreement was found by considering wave excitation exclusively associated with a proton beam reflected from a position on the bowshock at which the shock normal is parallel to the ambient IMF direction. Other geometries were found to be either impropitious or uncertain. The work indicates the useful diagnostic role QP emissions could play in the study of compressional ULF waves in the upstream solar wind and in monitoring the IMF conditions responsible for their generation.last_img read more

Local, regional and global patterns of resource use in ecology: hermit crabs and gastropod shells as an example

first_imgTo see the ‘big pictures’, it seems increasingly clear that experimental design, data collection and analyses of ecological investigation need to be at multiple scales. This causes problems with data complexity, sampling (level) and independence. Many ecological programmes are currently conducting multi-scale investigation of organismal trends (e.g. diversity). In this study, by contrast, the assemblages analysed were the resources used by animals (rather than animals per se). Variability in shell use was studied in 5 members of a taxon (hermit crabs) from global to site spatial levels. The novel adaptation of an existing technique used 1-factor, 3-level ANOVA of Bray-Curtis similarity values based on ‘centroids’ for each scale. Similarity in the number of shells used, the proportional usage of shell types, shell diversity and other variables were examined at site (> 10 m apart), locality (> 1 km apart) and region levels (> 1000 km apart). There was significant variability amongst scales and between regions in shell use of all species. For some species, observed variability differed with location, while in others the trend was similar in all 3 regions. Between 18 and 3 shell types were used by different study species with diversity (Shannon H’) values ranging from 2.54 to 0.1 and evenness values from 0.99 to 0.1. Shell use by hermit crabs was less similar (to each other) between regions than between the study hermit crab species. No significant spatial effects at any level were found on the proportion of damaged shells used by different species. The numbers of shell types used by hermit crabs had both a taxon-specific component and a global pattern. Data from the literature in combination with that from the present study showed Dardanus, Diogenes and Pagurus species used fewer shell types than Coenobita, Clibanarius and Calcinus species. No inter-oceanic patterns were evident in any genus. Shell numbers used by Clibanarius and Calcinus species both, however, exhibited distinct latitudinal clines. Adaptation of a novel technique has, thus, demonstrated global (and differential between scale) trends in resource use by a guild of animals, although interpretation of the mechanism or meaning underlying this is not straightforward.last_img read more

Implications for high latitude gondwanide palaeozoogeographical studies of some new Upper Cretaceous marine ostracodfaunas from New Zealand and the Antarctic Peninsula

first_imgSixty species of Ostracoda have been recovered from Cenomanian, Santonian and Maastrichtian strata in New Zealand, and late Campanian sediments on Snow Hill and James Ross islands in the Antarctic Peninsula. The two main New Zealand sites are in latest Maastrichtian strata, but in contrasting thermal regimes – warm, shelfal facies at Waipara, and cool, outer shelf/upper slope at Pukehou. Thepalaeozoogeographical history of several important taxa across the K/T boundary in Gondwanaland is clarified by the new data: Rostrocytheridea survived at Pukehou to within a few metres of the K/T, while Majungaella was found ~0.5 m from the top of the Maastrichtian at Waipara. The previously-known retrothermal propensities of Majungaella can be traced to the Maastrichtian at Pukehou,where a similar adaptation is observed in Rostrocytheridea, and possibly in Krithe. The first two genera became extinct across Mesozoic/ Tertiary boundary in Australasia, while in the Patagonia-Antarctic Peninsula region, Majungaella survived and colonised much of the Antarctic seaboard, but Rostrocytheridea probably did not survive into the Palaeogene. The extant genus Ameghinocythere is nowknown from late Campanian of Snow Hill Island, and also occurs in the late Maastrichtian in New Zealand. The earliest record of the widely distributed Gondwanide genus Apateloschizocythere is probably from the Cenomanian at Coverham, New Zealand. Nine new species are described: Ameghinocythere lutheri, A. eagari, Apateloschizocythere? colleni, Limburgina postaurora, Majungaella wilsoni,M. waiparaensis, Parahystricocythere ericea, Rayneria? punctata, Rostrocytheridea pukehouensis and Trachyleberis hornibrooki. The genus Parahystricocythere is new.last_img read more

Geographic variation in the foraging behaviour of South American fur seals

first_imgThe implicit assumption of many ecological studies is that animal behaviour and resource use are geographically uniform. However, central place foraging species often have geographically isolated breeding colonies that are associated with markedly different habitats. South American fur seals Arctocephalus australis (SAFS) are abundant and widely distributed colonial breeding central place foragers that provide potentially useful insights into geographic variation in animal behaviour and resource use. However, SAFS movement ecology is poorly understood. To address knowledge gaps and to explicitly test geographic variation in behaviour, we examined the foraging behaviour of 9 adult female SAFS from 2 Falkland Islands breeding colonies separated in distance by 200 km. A total of 150 foraging trips over 7 mo revealed striking colony differences. Specifically, SAFS that bred at Volunteer Rocks undertook long foraging trips (mean ± SD: 314 ± 70 km and 15.2 ± 2.7 d) to the Patagonian Shelf and shelf slope (bathymetric depth: 263 ± 28 m). In contrast, SAFS that bred at North Fur Island undertook short foraging trips (94 ± 40 km and 5.3 ± 2.1 d) and typically foraged near the Falkland Islands coastline (bathymetric depth: 85 ± 24 m). Stable isotope analysis of vibrissae δ13C and δ15N values also revealed colony differences in the isotopic niche area occupied, which indicated that resource use also differed. Contrary to popular models (Ashmole’s halo, hinterland model), colony size was unrelated to distance travelled, and SAFS did not necessarily use foraging grounds closest to their breeding colony. SAFS are likely subject to different selective pressures related to different environmental demands at the 2 breeding colonies. Accordingly, we reason that behavioural differences between breeding colonies reflect different phenotypes, and habitat use is more immediately influenced by phenotype, philopatry and the local environment, rather than density-dependent competition typically attributed to colony segregation in foraging areas.last_img read more

Death penalty won’t be pursued against NBA player Lorenzen Wright’s accused killers

first_imgMarch 19, 2018 /Sports News – National Death penalty won’t be pursued against NBA player Lorenzen Wright’s accused killers Written by FacebookTwitterLinkedInEmailABCNews.com(MEMPHIS, Tenn.) — The two accused killers of NBA player Lorenzen Wright — including his former wife — are set to appear in court together for the first time today for allegedly shooting the athlete nearly eight years ago.Wright’s ex-wife, Sherra Wright, is accused of conspiring with Billy Turner to fatally shoot the 34-year-old basketball player in July 2010, the Shelby County District Attorney’s Office in Tennessee said.Lorenzen and Sherra Wright had filed for divorce in May 2009, according to Shelby County courts.Lorenzen Wright, a Memphis native, was last seen alive leaving his ex-wife’s home in Collierville, Tennessee, on July 18, 2010, the district attorney’s office said. Early the next morning, a 911 call was made from his cellphone, but the call was interrupted by the sound of gunfire, the district attorney’s office said.A little more than a week later, on July 28, 2010, the NBA player’s body was found in a field, shot several times, the district attorney’s office said.The case went unsolved for years.Then last November, the alleged murder weapon was found in a lake near Walnut, Mississippi, prosecutors said.Turner was arrested first, indicted Dec. 5, 2017, on first-degree murder charges.Sherra Wright’s arrest and additional charges for Turner were announced by the district attorney’s office later that month: They were both indicted by a Shelby County grand jury on charges of first-degree premeditated murder, conspiracy to commit first-degree murder and attempted first-degree murder.They have pleaded not guilty, according to the Memphis Commercial Appeal.Copyright © 2018, ABC Radio. All rights reserved.center_img Beau Lundlast_img read more

Dixie State Returns To Road Once Again To Meet Colorado Mesa

first_img FacebookTwitterLinkedInEmailGRAND JUNCTION, Colo.-Saturday, Dixie State football returns to the road in hopes of getting back on the winning track in Rocky Mountain Athletic Conference football action.The Trailblazers will visit Grand Junction, Colo. to face the Colorado Mesa Mavericks for the 10th time in their NCAA Division II history as they seek their sixth win in conference play on the season.The Mavericks lead the Trailblazers 7-2 all-time, including a 4-1 mark in Grand Junction.Star Trailblazers tailback Sei-J Lauago continues to get closer to the all-time rushing record in program history.Lauago has 1,533 rushing yards in his career and only needs 190 more yards to surpass DeJon Coleman’s record, which dates back to 2015-16.The Trailblazers’ defense remains adept at getting after the quarterback as their 30 sacks are the most in the RMAC.Colorado Mesa’s offense presents an imposing challenge for this Trailblazers’ defense as quarterback Eystin Salum has run for 455 yards and six touchdowns while also throwing for 1,613 yards, 10 touchdowns and seven interceptions.Salum’s best receiver has proven to be Peter Anderson (50 rec, 1,028 yards, 7 TD’s).The Mavericks’ defense is led by defensive lineman Chance Drake (5 sacks) and defensive back Damar’ren Mitchell (5 interceptions).Colorado Mesa has not had a successful season as the Mavericks come in at 4-4 and 3-4 in conference play. After starting 3-0, they have dropped four of their last five. October 25, 2018 /Sports News – Local Dixie State Returns To Road Once Again To Meet Colorado Mesa Brad James Written by Tags: Chance Drake/Colorado Mesa/Damar’ren Mitchell/DeJon Coleman/Dixie State Football/Eystin Salum/NCAA Division II/Sei-J Lauagolast_img read more

Salt Lake Stallions Unveil New Uniforms, Draft Quarterback

first_imgNovember 27, 2018 /Sports News – Local Salt Lake Stallions Unveil New Uniforms, Draft Quarterback FacebookTwitterLinkedInEmailWEST JORDAN, Utah-Tuesday, the Salt Lake Stallions unveiled their new uniforms and drafted their first quarterback during a watch party at the ‘Bout Time Pub & Grub of West Jordan.The historic draft saw the Stallions select Josh Woodrum of Liberty in the first round of the Alliance of American Football’s “Protect or Pick” quarterback draft.During this draft, which originated out of Las Vegas, the Stallions had the option to protect one of the quarterbacks alloted to their roster or take a chance and pick an unprotected quarterback.The Stallions took the pick option and landed the undrafted Woodrum, who has most recently been with the Baltimore Ravens.Woodrum, a 6-3 228-pound signal-caller, is Liberty’s all-time record holder in passing yards (10,266), completions (833), total offense (10,960 yards) and touchdowns responsible for (77).The Stallions have also selected sky blue, royal blue and silver as their colors. The jerseys are designed by Starter and are largely silver, featuring royal blue jersey numbers outlined in sky blue and with sky blue along the collar and on the short sleeves.The pants are sky blue, featuring a royal blue stripe along the side.The Stallions’ season commences February 10 opens with a road game against the Arizona Hotshots. Written by Tags: Aliance of American Football/Arizona Hotshots/Baltimore Ravens/Josh Woodrum/Liberty/Protect or Pick/Salt Lake Stallions Brad Jameslast_img read more

Jeff Brohm to stay at Purdue, turns down Louisville head coaching job

first_imgNovember 28, 2018 /Sports News – National Jeff Brohm to stay at Purdue, turns down Louisville head coaching job Beau Lund Written bycenter_img FacebookTwitterLinkedInEmailPhoto by Eric Lars Bakke / ESPN Images(NEW YORK) — Purdue head football coach Jeff Brohm isn’t leaving West Lafayette, Indiana anytime soon, despite a chance to take the same job at his alma mater, Louisville.Brohm grew up in Louisville and played quarterback for the Cardinals. But after meeting with Louisville athletic director Vince Tyra on Tuesday, Brohm released a statement saying he would remain at Purdue.“Going home was very appealing and meaningful to me,” he admitted. But, he said, “the timing was not ideal.”Louisville went 2-10 this season, prompting the firing of their head coach Bobby Petrino. Purdue has gone 13-12 in two seasons under Brohm.  “After intense and thorough discussion, I believe it is important to finish the building process we have begun and honor the commitment I made to our football program, players, and recruits,” Brohm added in his statement. “…I believe that remaining at Purdue is the right thing to do, and I am excited for the challenges ahead.”Copyright © 2018, ABC Radio. All rights reserved.last_img read more

Prep Sports Roundup: 2/27

first_imgRICHFIELD, Utah-Hannah Morrill’s 22 points led the way as the Wayne Badgers routed Tabiona 56-33 Wednesday at Richfield High School in the first round of the 1-A girls basketball tournament. Abbie Rhoades had 8 points in the loss for the Tigers. Wayne next faces Panguitch Thursday at 4:00 pm at the Sevier Valley Center in the 1-A state quarterfinals. RICHFIELD, Utah-Jaime Montalvo posted 23 points and 6 rebounds and Rogelio Maldonaldo made a key go-ahead 3-pointer in the closing moments as Wendover outlasted Piute 69-68 Wednesday during the first round of the 1-A state boys tournament at the Sevier Valley Center. Kelby Jessup posted 24 points and 10 rebounds on 10-16 shooting and Wesley Jensen added 23 points and 6 rebounds on 9-15 from the field in defeat for the Thunderbirds, who shot 52.2 percent from the field for the game. Piute next plays Thursday at 8:30 pm in the consolation bracket at Richfield High School against Green River. Wendover advances to the 1-A state quarterfinals at the Sevier Valley Center Thursday at 8:30 pm. against Rich. February 27, 2019 /Sports News – Local Prep Sports Roundup: 2/27 RICHFIELD, Utah-Treyson Roberts posted 18 points and 12 rebounds on 6-11 shooting and converted a key 3-point play opportunity in overtime as the Bryce Valley Mustangs outlasted Milford 46-44 Wednesday in the first round of the 1-A state boys basketball tournament at the Sevier Valley Center. Sergio Vasquez added 13 points in the win for the Mustangs, who will next play Manila Thursday at 2:30 pm at the Sevier Valley Center in the 1-A state quarterfinals. Alec Williams had 12 points and 5 rebounds in the loss for the Tigers, who play Diamond Ranch Thursday at 2:30 pm in the consolation bracket at Richfield High School. 1-A Girls Basketball Opening Round @ Richfield H.S. Brad James FacebookTwitterLinkedInEmail1-A Boys Basketball Opening Round State @ SVC Written bycenter_img RICHFIELD, Utah-Dakota Young posted 22 points and 7 rebounds on 9-12 shooting as the Tabiona Tigers clobbered Wayne 69-39 during the first round of the 1-A state boys tournament at the Sevier Valley Center Wednesday. Garrett Chappell had 11 points in defeat for the Badgers. Wayne next plays in the Thursday 7:00 pm game in the consolation bracket at the Sevier Valley Center. Tabiona advances to the 7:00 pm quarterfinal Thursday at the Sevier Valley Center against Valley or Whitehorse. RICHFIELD, Utah-Jordyn Kennedy’s 11 points led the way as the Piute Thunderbirds downed Tintic 59-24 Wedesday in the first round of the 1-A girls basketball tournament at Richfield High School. Kalynn Livingston had 7 points in the loss for the Miners. Piute next faces Monument Valley Thursday at 11:30 am in the 1-A state quarterfinals at the Sevier Valley Center. RICHFIELD, Utah-Acey Orton posted 32 points and 10 rebounds on 12-17 shooting as the Panguitch Bobcats routed Tintic 71-38 Wednesday in the first round of the 1-A state boys basketball tournament at the Sevier Valley Center. The Bobcats shot 50.9 percent for the game en route to their berth in the state quarterfinals for a 1:00 pm tip-off against the winner of Monticello and Water Canyon. McCoy Fitzgerald and Jacob Whitney had 11 points apiece in defeat for the Miners. Tags: 1-A state tournament/Jaime Montalvo/Kelby Jessup/Piute/Rogelio Maldonado/Sevier Valley Center/Wendover/Wesley Jensen RICHFIELD, Utah-Orrin Wood posted 12 points on 5 of 8 shooting and Cameron Franklin added 10 points and 9 rebounds as the Valley Buffaloes downed Whitehorse 59-25 Wednesday in the first round of the 1-A state tournament at the Sevier Valley Center. Lanedon Bob had 9 points and 6 rebounds in the loss for the Raiders. The Buffaloes next face Tabiona Thursday at 7:00 pm in the state quarterfinals at the Sevier Valley Center. Lanedon Bob had 9 points in the loss for the Raiders, who face Wayne Thursday at 7:00 pm in the consolation bracket at Richfield High School. RICHFIELD, Utah-Camri Fischer led the way with 16 points and the Panguitch Bobcats embarrassed West Desert 83-9 in the first round of the 1-A girls basketball tournament Wednesday at Richfield High School. Kayli Baker had 5 points in the loss for the Hawks.last_img read more