The Ancestral South Sandwich Arc (ASSA) has a short life-span of c.20 m.y. (Early Oligocene to Middle-Upper Miocene) before slab retreat and subsequent ‘resurrection’ as the active South Sandwich Island Arc (SSIA). The ASSA is, however, significant because it straddled the eastern margin of the Drake Passage Gateway where it formed a potential barrier to deep ocean water and mantle flow from the Pacific to Atlantic. The ASSA may be divided into three parts, from north to south: the Central Scotia Sea (CSS), the Discovery segment, and the Jane segment. Published age data coupled with new geochemical data (major elements, trace elements, Hf-Nd-Sr-Pb isotopes) from the three ASSA segments place constraints on models for the evolution of the arc and hence gateway development. The CSS segment has two known periods of activity. The older, Oligocene, period produced basic-acid, mostly calc-alkaline rocks, best explained in terms of subduction initiation volcanism of Andean-type (no slab rollback). The younger, Middle-Late Miocene period produced basic-acid, high-K calc-alkaline rocks (lavas and pyroclastic rocks with abundant volcanigenic sediments) which, despite being erupted on oceanic crust, have continental arc characteristics best explained in terms of a large, hot subduction flux most typical of a syn- or post-collision arc setting. Early-Middle Miocene volcanism in the Discovery and Jane arc segments is geochemically quite different, being typically tholeiitic and compositionally similar to many lavas from the active South Sandwich island arc front. There is indirect evidence for Western Pacific-type (slab rollback) subduction initiation in the southern part of the ASSA and for the back-arc basins (the Jane and Scan Basins) to have been active at the time of arc volcanism. Models for the death of the ASSA in the south following a series of ridge-trench collisions, are not positively supported by any geochemical evidence of hot subduction, but cessation of subduction by approach of progressively more buoyant oceanic lithosphere is consistent with both geochemistry and geodynamics. In terms of deep ocean water flow the early stages of spreading at the East Scotia Ridge (starting at 17-15 Ma) may have been important in breaking up the ASSA barrier while the subsequent establishment of a STEP (Subduction-Transform Edge Propagator) fault east of the South Georgia microcontinent (< 11 Ma) led to formation of the South Georgia Passage used by the Antarctic Circumpolar Current today. In terms of mantle flow, the subduction zone and arc root likely acted as a barrier to mantle flow in the CSS arc segment such that the ASSA itself became the Pacific-South Atlantic mantle domain boundary. This was not the case in the Discovery and Jane arc segments, however, because northwards flow of South Atlantic mantle behind the southern part of the ASSA gave an Atlantic provenance to the whole southern ASSA.
Forget the world’s biggest cupcake, Sayers and Hampsons devised the world’s smallest cupcakes or so they claimed. A Guinness Book of Records entry has never actually been recorded. The cake measured only 3cm in height and was 1.5cm in diameter.
Oxford has announced today that it will run Massive open online courses (Moocs) for the first time, in connection with US platform edX. It will begin enrolling students for a course, beginning in February 2017, called “From Poverty to Prosperity: Understanding Economic Development”.The course will look at the role governments play as a catalyst for economic development. It will be headed by Sir Paul Collier, professor of economics and public policy at the Blavatnik School of Government.Moocs, free online courses typically based around lectures and readings, are an increasingly popular form of distance learning. They have seen exceptional growth in the USA in recent years, and have been praised for increasing access and affordability of higher education resources.The edX platform, also used by Harvard, the Sorbonne and the Massachusetts Institute of Technology, has nine million registered students and hosts over 900 online courses.Sarah Whatmore, pro vice-chancellor for education, said that the new project “will build capacity for the design and delivery of a range of other online education experiences.”“Oxford already has a strong reputation for delivering open educational resources that are used by students, academics and the public worldwide,” she added.Anant Agarwal, chief executive of edX and professor at the Massachusetts Institute of Technology, said the company was delighted that Oxford had joined the edX platform.“Our collaboration begins with content from the Blavatnik School to provide our nine million learners with access to an innovative programme that offer insights from a range of academic disciplines and a strong global outlook,” he said.“We are excited to partner with Oxford to further our shared mission to improve lives and increase access to high quality education for learners everywhere.”
Businesses with a turnover of more than £36 million are already legally required to publish annual transparency statements, known as a Modern Slavery Statements, setting out what they are doing to stop modern slavery and forced labour practices occurring in their business and supply chains.Last month, to coincide with Anti-Slavery Day, the Home Office wrote directly to the Chief Executives of 17,000 businesses to remind them of their responsibilities, or face being publicly named. Modern slavery is an abhorrent crime that denies its victims of liberty, and it is disturbing to think that some of the products we buy could have been produced by someone exploited into forced labour. As global leaders in the fight against modern slavery, I am clear that this will not be tolerated in the UK – and our consumers won’t stand for it either. I welcome the action being taken by businesses which are leading the way in being open and transparent about the modern slavery risks they face, and have pledged to raise awareness to prevent slavery, protect vulnerable workers and help bring more criminals to justice. But with Modern Slavery police operations at an all-time high, clearly there is more to do to stamp out this vile crime and prevent criminal groups from operating in the shadows of supply chains to exploit people for commercial gain. The announcement follows the latest meeting of the Modern Slavery Taskforce, created by Prime Minister Theresa May, which discussed how to better identify and tackle forced labour in business supply chains.The UK’s multi-billion fashion industry employs tens of thousands of people, which can make its companies vulnerable to unscrupulous providers and criminals who exploit workers for their labour.The new agreement will commit its signatories, John Lewis, M&S, New Look, NEXT, River Island and Shop Direct, to work together with the Gangmasters and Labour Abuse Authority (GLAA), and others, to root out criminality and shine a light on hidden victims.These efforts to uncover hidden slavery in businesses come as activity to respond to modern slavery offences has reached an all-time high, with police forces across the UK running more than 920 live investigations in September, involving over 2,000 victims.The Prime Minister said: