Volcanic history of Mount Sidley, a major alkaline volcano in Marie Byrd Land, Antarctica

first_imgMount Sidley is a complex, polygenetic stratovolcano composed primarily of phonolitic and trachytic lavas and subordinate pyroclastic lithologies at the southern extremity of the Executive Committee Range, a linear chain of volcanoes in central Marie Byrd Land, Antarctica. Detailed field investigation coupled with 14 high precision 40Ar/39Ar age determinations reveal a 1.5 million year life span between 5.7 and 4.2 Ma in which three major phonolitic central vent edifices (Byrd, Weiss and Sidley volcanoes) and their calderas were developed (5.7–4.8 Ma). This was followed (4.6–4.5 Ma) by the eruption of trachytic magmas from multiple vent localities further south, and then by small volume benmoreite-mugearite lavas and tephras around 4.4–4.3 Ma at the southern end of Mount Sidley. The final phase of activity was the eruption of basanite cones at approximately 4.2 Ma. The southward migration of volcanic activity was accompanied by distinct changes in magma composition and is best explained by the sequential release of magmas stored within an intricate system of conduits and chambers in the crust by tectonically driven (magma assisted?) fracture propagation. The style of volcanic migration at Mount Sidley is emulated on a larger scale by other volcanoes in the Executive Committee Range, in which progressive southward displacement of volcanic activity corresponds with significant petrological variations between major centers.last_img read more

Letters to the Editor for Wednesday, June 26

first_imgCategories: Letters to the Editor, OpinionDriver’s license bill promotes illegalityIt seems that when the cats (Republicans) are away, the mice (children) will play.Every radical bill was sailing through the Legislature because there’s no longer the Republican Senate to act as a buffer. Stop bashing or run for office yourselfI’m constantly viewing late night talk show hosts and various media anchors who consistently bash our U.S. president.If the bashers had any courage or stand behind their comments then they should run for office, but no they won’t.It’s easy to bash someone that you have no idea of their career duties.They are the weak link.Anthony MazzoneGlenvilleMore from The Daily Gazette:Foss: Should main downtown branch of the Schenectady County Public Library reopen?Gov. Andrew Cuomo’s press conference for Sunday, Oct. 18EDITORIAL: Thruway tax unfair to working motoristsEDITORIAL: Beware of voter intimidationEDITORIAL: Find a way to get family members into nursing homes Like I’ve said before, people who live in glass houses should not throw stones. Rep. Paul Tonko, you are a bad American citizen and congressman. You help the immigrants who are in this country illegally, but you don’t help the 100 percent disabled veterans. You Democratic liberals spend millions of our tax dollars on this stupid Russian election interference.Why didn’t you liberals investigate the uranium deal made while Hillary Clinton was secretary of state, and when our men were killed in Benghazi? I am a good American Democrat, not a liberal. I fought for my country and other veterans. If anyone should be impeached, Mr. Tonko, it should be you. I will keep fighting you until you do the good for the country and us veterans or resign from Congress.Vincent BelardoAlbanycenter_img The most recent act of lunacy was giving driver’s licenses to immigrants in this country illegally.The debate was basically non-existent because the Democrats hurled labels at the Republicans such as “racist” and “xenophobe,” and that effectively ended things. The Democrats chirped about how much more convenient this would be for these individuals. How nice. They’re rewarded for breaking the law, instead of having to do things the right way — the legal way.The Republicans questioned the Democrats if these licenses could be used to register to vote. The Democrats implied that that was extremely unlikely, because these are very hardworking individuals who would never do anything illegal like that. Poppycock.Our voter registration system is basically an “honor system.” It asks two questions: 1) Are you a U.S. citizen? and 2) Do you want to register to vote? Verification is spotty at best. These migrants traveled hundreds of miles to sneak illegally into our country.Do you honestly think they’re going to answer those questions truthfully?Democrats are treating U.S. citizens, New Yorkers, shabbily. The 2020 election is right around the corner, and what goes around, comes around. And remember, an elephant never forgets.Ken TrumanAlbanyTonko should do a better job or resignlast_img read more