Spiess Ridge: An axial high on the slow spreading Southwest Indian Ridge

first_imgWe report recent mapping of Spiess Ridge with the Hawaii-MR1 sidescan sonar. Spiess Ridge is an unusual elongate 90 by 50 km volcanic feature on the slow spreading Southwest Indian Ridge near the Bouvet hotspot. The northwest half of the ridge has a narrow ∼7-km neovolcanic zone in MR1 sonar images and a simple magnetic anomaly sequence including possible anomalies C1n and C2n. In contrast, the southeast half shows extrusive volcanism over >40 km with distributed eruption sites, a broadened central magnetic anomaly with no anomaly C2n, and a volcanic ridge radiating from the summit of Spiess Ridge, oblique to the spreading orthogonal trend. The images show no evidence for large-offset normal faults or an axial rift valley typical of slow spreading ridges. Overall, Spiess Ridge has an appearance very unlike that of either fast or slow spreading ridges and more transitional between a spreading ridge and a seamount. We compare the morphology of Spiess Ridge to other large volcanic structures in oceanic rifts. Spiess Ridge and Bouvet Island represent localized zones of excess melting along the Southwest Indian Ridge and we discuss their origin in the light of current ideas on ridge-hotspot interaction.last_img read more

Neoproterozoic extensional basic magmatism associated with the West Highland granite gneiss in the Moine Supergroup of NW Scotland

first_imgPre-tectonic metagabbroic rocks emplaced into the Glenfinnan and Loch Eil groups of the Moine Supergroup give a U–-Pb zircon age of 873 ± 6 Ma. This new age for the metagabbros confirms the absence of Grenvillian (c. 1.0 Ga) tectonic events in the Moine assemblage. The metagabbros are spatially associated with the Glen Doe body of the West Highland granite gneiss, and were emplaced soon after the granite gneiss protolith. The metagabbros have chemical characteristics indicating contamination with local country rocks. A regionally developed suite of tholeiitic metadolerite dykes post-dates the metagabbros. These dykes are geochemically similar to modern mid-ocean ridge basalt, albeit modified by interaction with metamorphic fluids. The presence of abundant MORB-like basaltic dykes, coupled with the lack of major compressional structures associated with the intrusive events, suggests that the c. 873 Ma event may have been dominated by extensional tectonics.last_img read more

Towards improved empirical isobase models of Holocene land uplift for mainland Scotland, UK

first_imgA new approach to modelling patterns of glacio-isostatic land uplift during the Holocene in mainland Scotland, UK, is described. The approach is based upon altitude measurements at the inner margin or locally highest point of raised estuarine surfaces dated by radiocarbon assay supported by microfossil analyses. 2241 altitudes have been analysed by a technique new to studies of former sea-levels, Gaussian Trend Surface Analysis, and isobase models for four Holocene shorelines: the Holocene Storegga Slide tsunami shoreline, abandoned rapidly circa 7900 sidereal years BP; the Main Postglacial shoreline, abandoned during circa 6400–7700 sidereal years BP; the Blairdrummond shoreline, abandoned during circa 4500–5800 sidereal years BP, and a speculative fourth shoreline, the Wigtown shoreline, abandoned during circa 1520–3700 sidereal years BP, are shown in a series of maps. The implications of the shoreline patterns for glaicio-isostasy in the area are discussed. It is maintained that the statistical technique used enables broad estimates to be made of nearshore sea surface change.last_img read more

Detection and attribution of Antarctic climate change

first_imgThe current understanding of climate changes that have occurred in the last 50 years over Antarctica is presented with a focus on: (i) a summer warming of the eastern Antarctic Peninsula, which caused the collapse of the larsen B ice shelf, (ii) the observed significant increase of total sea ice extent and (iii) an anthropogenic ‘fingerprint’ in the Antarctic-wide temperature change pattern. The implications of this for predictions of the future are discussed.last_img

Global patterns of declining temperature variability from the Last Glacial Maximum to the Holocene

first_imgChanges in climate variability are as important for society to address as are changes in mean climate1. Contrasting temperature variability during the Last Glacial Maximum and the Holocene can provide insights into the relationship between the mean state of the climate and its variability2,3. However, although glacial–interglacial changes in variability have been quantified for Greenland2, a global view remains elusive. Here we use a network of marine and terrestrial temperature proxies to show that temperature variability decreased globally by a factor of four as the climate warmed by 3–8 degrees Celsius from the Last Glacial Maximum (around 21,000 years ago) to the Holocene epoch (the past 11,500 years). This decrease had a clear zonal pattern, with little change in the tropics (by a factor of only 1.6–2.8) and greater change in the mid-latitudes of both hemispheres (by a factor of 3.3–14). By contrast, Greenland ice-core records show a reduction in temperature variability by a factor of 73, suggesting influences beyond local temperature or a decoupling of atmospheric and global surface temperature variability for Greenland. The overall pattern of reduced variability can be explained by changes in the meridional temperature gradient, a mechanism that points to further decreases in temperature variability in a warmer future.last_img read more

A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations

first_imgThe Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the European Space Agency (ESA) Envisat satellite operated from July 2002 to April 2012. The infrared limb emission measurements provide a unique dataset of day and night observations of polar stratospheric clouds (PSCs) up to both poles. A recent classification method for PSC types in infrared (IR) limb spectra using spectral measurements in different atmospheric window regions has been applied to the complete mission period of MIPAS. The method uses a simple probabilistic classifier based on Bayes’ theorem with a strong independence assumption on a combination of a well-established two-colour ratio method and multiple 2-D probability density functions of brightness temperature differences. The Bayesian classifier distinguishes between solid particles of ice, nitric acid trihydrate (NAT), and liquid droplets of supercooled ternary solution (STS), as well as mixed types. A climatology of MIPAS PSC occurrence and specific PSC classes has been compiled. Comparisons with results from the classification scheme of the spaceborne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite show excellent correspondence in the spatial and temporal evolution for the area of PSC coverage (APSC) even for each PSC class. Probability density functions of the PSC temperature, retrieved for each class with respect to equilibrium temperature of ice and based on coincident temperatures from meteorological reanalyses, are in accordance with the microphysical knowledge of the formation processes with respect to temperature for all three PSC types. This paper represents unprecedented pole-covering day- and nighttime climatology of the PSC distributions and their composition of different particle types. The dataset allows analyses on the temporal and spatial development of the PSC formation process over multiple winters. At first view, a more general comparison of APSC and AICE retrieved from the observations and from the existence temperature for NAT and ice particles based on the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis temperature data shows the high potential of the climatology for the validation and improvement of PSC schemes in chemical transport and chemistry–climate models.last_img read more

1952 Mickey Mantle baseball card sells for $2.88 million: Report

first_img FacebookTwitterLinkedInEmailABCNews.com(NEW YORK) — A 1952 Mickey Mantle baseball card in mint condition sold for $2.88 million Thursday — making it the second-highest price ever paid for a baseball card, ESPN reported.The card, sold by former NFL offensive lineman Evan Mathis and auctioned by Heritage Auctions, fell just short of the $3.12 million paid for a 1909 Honus Wagner card in October 2016, according to the report.The Mickey Mantle card was graded a 9 on a scale of 10 by Professional Sports Authenticator, an organization that describes itself as the “world’s largest third-party sports card authentication service.”The value of the late Hall of Famer’s rookie card has gone up dramatically in the last few decades, ESPN reported.In 1988, the card could be had for $3,300; by 2007, the top sale of the card, also graded a 9 out of 10, was $240,000, according to the report.“It’s a remarkable price,” Chris Ivy, director of sports auctions at Heritage, told ESPN. “It was 10 years ago when we last had a Mantle 9 sell, but this sold for 10 times that.”Prior to Thursday night’s auction, the record for the card was set at $1.13 million in 2016.Mantle spent his entire 18-year career with the New York Yankees, according to the Baseball Hall of Fame. He was selected to the All-Star game 20 times, won the most valuable player award three times, and was part of seven World Series-winning teams.Mantle was enshrined in the National Baseball Hall of Fame in 1974.Copyright © 2018, ABC Radio. All rights reserved. Beau Lund April 20, 2018 /Sports News – National 1952 Mickey Mantle baseball card sells for $2.88 million: Reportcenter_img Written bylast_img read more

Marlins’ season on hold due to COVID-19

first_imgJuly 29, 2020 /Sports News – National Marlins’ season on hold due to COVID-19 FacebookTwitterLinkedInEmailmanusapon kasosod/iStockBy ABC News(NEW YORK) — Just days after kicking off their shortened regular season, the Miami Marlins have put gameplay on hold.Major League Baseball announced on Tuesday that the team’s games will be postponed through Sunday after numerous Marlins players were diagnosed with COVID-19.“Given the current circumstances, MLB believes that it is most prudent to allow the Marlins time to focus on providing care for their players and planning their Baseball Operations for a resumption early next week,” the league said in a statement.“The Marlins’ personnel who tested positive remain in isolation and are receiving care,” the league said.ESPN reported Monday that multiple Marlins players had COVID-19 — one day after the Marlins played the Philadelphia Phillies. The Phillies’ Monday night game against the New York Yankees was canceled, as was the Marlins’ Monday night game against the Baltimore Orioles.“Out of an abundance of caution, the remainder of the home-and-home series between the Philadelphia Phillies and the New York Yankees has been postponed (NYY @ PHI tonight, and PHI @ NYY Wednesday and Thursday),” MLB said Tuesday. “As a result of these postponements, the Yankees will now play the Baltimore Orioles at Camden Yards on Wednesday and Thursday in order to create more scheduling flexibility later in the season. Additional rescheduling during the week of August 3rd will be announced later this week.”The Marlins began their 60-game season last Friday against the Phillies, winning two out of the three games in the series.Copyright © 2020, ABC Audio. All rights reserved. Beau Lundcenter_img Written bylast_img read more

Shearwater GeoServices awarded 1st Latin American Isometrix survey by Ecopetrol

first_img Image: Shearwater GeoServices secured Latin American Isometrix survey contract from Ecopetrol. Photo: Courtesy of Shearwater GeoServices. Shearwater GeoServices announced the award of a 3D Isometrix seismic survey by Colombia’s Ecopetrol S.A. It will be the first Isometrix survey in Latin America with marine acquisition starting in Q4 2019.The survey covers 2 000 sq. km of 3D seismic offshore Colombia on Ecopetrol’s Block COL-5 and will acquired by the SW Amundsen equipped with Isometrix multisensor streamer technology. Isometrix streamer technology is a true 3D multisensor system that can record the full seismic wavefield enabling better receiver deghosting and improved seismic images. The survey is expected to take 1.5 months to complete.“We continue to deliver on our strategy to expand our presence in Latin America. A cornerstone of that strategy is to leverage Shearwater’s unique technology such as our market-leading multisensor streamer solution,” said Irene Waage Basili, the CEO of Shearwater GeoServices. “We are very pleased with the award by Ecopetrol which will be our first survey in Colombia, the first project for a new leading regional customer, and the first-ever Latin American Isometrix project.”Shearwater experiences increased activity in Latin America and has established a new Colombian branch to support this coming operation. This follows the recent opening of a branch office in Brazil to support Shearwater’s growth in the region. Source: Company Press Release Shearwater experiences increased activity in Latin America and has established a new Colombian branch to support this coming operationlast_img read more

TransAlta and Tidewater Midstream to sell Pioneer Pipeline to ATCO

first_img TansAlta to sell Pioneer Pipeline to ATCO Gas. (Credit: Pixabay/David Mark.) TransAlta and its partner Tidewater Midstream & Infrastructure have signed an agreement with ATCO Gas and Pipelines, a subsidiary of Canadian Utilities, to sell Pioneer Pipeline for C$255m ($192m).Pioneer Pipeline is a 131km natural gas pipeline that runs from the Drayton Valley area to the Wabamun area west of Edmonton, Alberta, Canada. The throughput from the pipeline is about 130MMcf/d of natural gas.The agreement replaces TransAlta’s agreement to sell the pipeline to NOVA Gas Transmission. However, most of the agreement terms remain substantially the same.Canadian Utilities president and CEO Siegfried Kiefer said: “This transaction continues to illustrate ATCO’s commitment to understand and support our customers’ evolving needs and develop solutions that support the transition to a lower-emitting energy system.”Pioneer Pipeline will be integrated into NGTL’s and ATCO’s Alberta natural gas transmission systemsAfter the transaction is closed, Pioneer Pipeline will be integrated into NGTL’s and ATCO’s Alberta natural gas transmission systems, supplying reliable natural gas to TransAlta’s power generation stations at Sundance and Keephills.The gas supply agreement will help to facilitate in converting the coal-fired power plants to be powered by natural gas.As part of the transaction, TransAlta has also entered into a long-term gas supply agreement with NGTL for a total of 400 TJ/day by 2023.Subject to customary regulatory approvals, the deal is expected to be closed in the second quarter of next year.TransAlta president and CEO Dawn Farrell said: “We are excited to work with both ATCO and NGTL to meet our gas supply requirements as we execute our strategy of providing 100% clean, reliable and affordable electricity to Albertans.”In June this year, TransAlta announced that it will sell the pipeline to NOVA Gas Transmission, a subsidiary of TC Energy for C$255m ($192m).Tidewater Midstream said that the proceeds from the transaction will be split equally between Tidewater and TansAlta. The 131km natural gas runs between Drayton Valley area and Wabamun area west of Edmonton, Alberta, Canadalast_img read more