Abrupt mid-Holocene ice loss in the western Weddell Sea Embayment of Antarctica

first_imgThe glacial history of the westernmost Weddell Sea sector of Antarctica since the Last Glacial Maximum is virtually unknown, and yet it has been identified as critical for improving reliability of glacio-isostatic adjustment models that are required to correct satellite-derived estimates of ice sheet mass balance. Better knowledge of the glacial history of this region is also important for validating ice sheet models that are used to predict future contribution of the Antarctic ice sheet to sea level rise. Here we present a new Holocene deglacial chronology from a site on the Lassiter Coast of the Antarctic Peninsula, which is situated in the western Weddell Sea sector. Samples from 12 erratic cobbles and 18 bedrock surfaces from a series of presently-exposed ridges were analysed for cosmogenic 10Be exposure dating, and a smaller suite of 7 bedrock samples for in situ 14C dating. The resulting 10Be ages are predominantly in the range 80–690 ka, whereas bedrock yielded much younger in situ 14C ages, in the range 6.0–7.5 ka for samples collected from 138–385 m above the modern ice surface. From these we infer that the ice sheet experienced a period of abrupt thinning over a short time interval (no more than 2700 years) in the mid-Holocene, resulting in lowering of its surface by at least 250 m. Any late Holocene change in ice sheet thickness — such as re-advance, postulated by several modelling studies — must lie below the present ice sheet surface. The substantial difference in exposure ages derived from 10Be and 14C dating for the same samples additionally implies ubiquitous 10Be inheritance acquired during ice-free periods prior to the last deglaciation, an interpretation that is consistent with our glacial-geomorphological field observations for former cold-based ice cover. The results of this study provide evidence for an episode of abrupt ice sheet surface lowering in the mid-Holocene, similar in rate, timing and magnitude to at least two other locations in Antarctica.last_img read more

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Berbice High, NATI, PC and Kwakwani into National Schools Basketball Festival semis

first_imgBERBICE High School, New Amsterdam Technical Institute (NATI), Kwakwani Secondary and President’s College (PC) emerged victorious in the quarterfinals of the 14th edition of the Youth Basketball Guyana (YBG)-organised National Schools Basketball Festival, which was played on Monday at Cliff Anderson Sports Hall.This was the first year that schools from Berbice dominated the final eight. According to information, this is also the first year that no Linden-based team qualified for the semi-finals.President’s College will also look to become the first East Coast team to win the competition. What was not a surprise was the qualification of Kwakwani Secondary, who have been a dominant force.Prior to this year, the competition was at the U-19 level and over its 14 years, Kwakwani had won six titles. The only team who had threatened the Berbice River school was back-to-back winners, Linden Technical Institute (LTI), who did not field a team this year. In total, LTI have five wins at the older age group level.BIG WINSIn their quarterfinal clashes, President’s College and NATI registered big wins.In a rematch of last month’s Georgetown and East Coast Demerara Regional final, President’s College once again defeated Marian Academy, unlike the eight-point (72-64) victory then, this game was a 26-point (53-27) blowout.Jushaun Bayley led PC with 14 points, while Richard Semple added eight points, five assists seven rebounds and Akinyele Derrell eight points.Jether Harris finished with nine points nine rebounds for Marian Academy.Berbice Regional winners NATI also registered a commanding victory when they competed against Mackenzie High School (MHS). Seasoned player Kadeem Dover, who shot his way to 20 points, orchestrated the 51-33 win. Gevon Schuttz added 15 points nine rebounds and Jermain King 12 points.Shamar Savory and Tyrese Arthur finished with 12 points, nine rebounds and eight points, seven rebounds respectively for MSC.Meanwhile Berbice High were able to overhaul St. Joseph High in the opener.The visiting school fought back from a 10-point deficit at the half, to register an eight-point win (37-29).Forward Kezron Cort scored 11 of his 14 points and pulled down six of seven rebounds in the second period, while Rickford Blair and Charles Williams were also instrumental in the latter stage.Blair, who scored 15 points on Sunday, finished with 10 points (eight in the second period), four rebounds two steals, while Williams finished with 11 points (seven in the second period) and seven rebounds.St Joseph, who drew a walkover victory against the LTI on Sunday, were led by Shaquawn Gill, who scored a game-high 15 points to go with nine rebounds. Gill (nine points) and Shaqueem Wilson (eight points) had combined for 17 of their team’s 19 points at the end of the first period, but with limited options in scoring, the Georgetown school saw their 10-point lead evaporate.In total, Wilson finished with 12 points.Meanwhile in a keen battle, Kwakwani Secondary School defeated Bishops’ High School.Raul Sampson exploded in the opening period after knocking down four shots from downtown to help the visiting school to a whopping 11-point lead.Although the Georgetown school battled back and finished with a better second period score, they fell seven points short 52-45. Royon Shortt (also nine rebounds) and Elijah David added nine points each for the winners.Roydon Glasgow led Bishops’ High with a game-high 19 points, 15 of which were scored in the second period.Action continued yesterday with the U-14 Boys group format and the Girls round-robin.Edward B. Beharry and Company Ltd, National Sports Commission, Banks DIH, ExxonMobil and Bounty Ltd are the Festival sponsors.last_img read more

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