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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula
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Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula

机译：阿拉斯加半岛卡特迈火山群的年代学和喷发史

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摘要

In the Katmai district of the Alaska Peninsula, K-Ar and ~(40)Ar/~(39)Ar ages have been determined for a dozen andesite-dacite stratocones on the arc front and for 11 rear-arc volcanoes, 10 of which are monogenetic. Tied to mapping and stratigraphic studies, our dating emphasized proximal basal lavas that rest on basement rocks, in order to estimate ages of inception of each polygenetic one. Oldest among arc-front cones is Alasgogshak Volcano (690-43 ka), succeeded in the Holocene by the active Mount Martin cone. Mount Mageik consists of four overlapping subedifices, basal lavas of which give ages of 93, 71, and 59 ka, and Holocene. The three small prehistroci cones of Trident Volcano yield ages of 143, 101-58, and 44 ka. Falling Mountain and Mount Cerberus, dacite domes near the 1912 Novarupta vent, are related compositonarlly to the Trident group and give ages of 70 ka and 114 ka. Mount Katmai, which underwent caldera collapse in 1912, consists of two subedifices that overlapped in space and time, and is the only arc-front center here to include basalt and rhyolte; one cone began by 90 ka, the other by 47 ka. Snowy Mountain also consists of two contiguous cones, which started around 200 and 171 ka, respectively, the younger remaining active into the Holocene. Devils Desk, the only manic cone on the arc front, was short-lived at about 245 ka. In the rear-arc, (1) Mount Griggs produced mafic-to-silicic andesite in several episodes between 292 ka and the Holocene; (2) the Savonoski river cluster includes a Pliocene dacite dome and five small manic cones (390-88 ka); (3)Gertrude Creek cone (49.8% SiO_2) yields an age of 500 ka; and (4) the Saddlehorn Creek Custer includes five Pliocene basalt-to-andesite remnants. Eruptive volumes were reconstructed, permitting estimates of average eruption rates for edifice lifetimes. Since the mid Pleistocene, total volume erupted along the arc front here is 210±47 km~3 and in the rear-arc 39±6 km~3, of which Mount Griggs alone accounts for 35±5 km~3. Most productive has been Mount Katmai at 70±18 km~3, yielding a rate of ～1 km~3/kyr, followed by Mount mageik (0.33 km~3/kyr) and Mount Griggs (0.3 km~3/kyr since 50 ka). Published by Elsevier B. V.
机译：在阿拉斯加半岛的卡特迈地区，已经确定了弧前的十二个安山岩-针ac石平顶锥和11个后弧火山的K-Ar和〜（40）Ar /〜（39）Ar年龄。是单基因的。为了与制图和地层学联系在一起，我们的测年法强调了基岩上的近端基底熔岩，以便估算每种多成岩的起始年龄。弧前锥中最古老的是阿拉斯哥火山（690-43 ka），由活动的马丁山锥在全新世后继。 Mageik山由四个重叠的子构造组成，其中基础熔岩的年龄分别为93、71和59 ka，以及全新世。三叉戟火山的三个小史前锥锥的年龄分别为143、101-58和44 ka。落山和Cerberus山是1912年Novarupta泄洪口附近的陶粒圆顶，与Trident族在构成上相关，年龄分别为70 ka和114 ka。卡特迈山（Katmai）在1912年遭受破火山口坍塌，由两个在空间和时间上重叠的子构造组成，并且是这里唯一包含玄武岩和扁晶的弧前中心。一个锥度开始于90 ka，另一个锥度开始于47 ka。雪山还由两个连续的圆锥体组成，分别开始于200和171 ka左右，年轻的保持活跃到全新世。魔鬼台是弧线上唯一的躁狂锥，寿命短于245 ka。在弧后，（1）格里格斯山在292 ka和全新世之间的几次发作中产生了镁铁质至硅质安山岩; （2）萨沃诺斯基河群包括一个上新世的陶粒穹顶和五个小的躁狂锥（390-88 ka）; （3）Gertrude Creek锥（49.8％SiO_2）的寿命为500 ka; （4）Saddlehorn Creek Custer包含5个上新世玄武岩至安山岩的残余物。重建了喷发量，可以估计建筑物生命的平均喷发率。自中更新世以来，沿弧前喷发的总量为210±47 km〜3，在弧后喷发的总量为39±6 km〜3，其中仅格里格斯火山就占35±5 km〜3。生产率最高的是卡特迈山（Mount Katmai），速度为70±18 km〜3，速率为〜1 km〜3 / kyr，其次是自50以来的玛格尼克山（0.33 km〜3 / kyr）和格里格斯山（0.3 km〜3 / kyr） K a）。由Elsevier B. V.发布

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