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首页> 外文期刊>Geosphere >Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska
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Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska

机译：平板电弧变换交界处的构造变化的地球化学和地理学记录：大约30 mA到CA. 19 Ma Sonya Creek火山火山，Wrangell Arc，阿拉斯加

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The Sonya Creek volcanic field (SCVF) contains the oldest in situ volcanic products in the ca. 30 Ma–modern Wrangell Arc (WA) in south-central Alaska, which commenced due to Yakutat microplate subduction initiation. The WA occurs within a transition zone between Aleutian subduction to the west and dextral strike-slip tectonics along the Queen Charlotte–Fairweather and Denali–Duke River fault systems to the east. New 40 Ar/ 39 Ar geochronology of bedrock shows that SCVF magmatism occurred from ca. 30–19 Ma. New field mapping, physical volcanology, and major- and trace-element geochemistry, coupled with the 40 Ar/ 39 Ar ages and prior reconnaissance work, allows for the reconstruction of SCVF magmatic evolution. Initial SCVF magmatism that commenced at ca. 30 Ma records hydrous, subduction-related, calc-alkaline magmatism and also an adakite-like component that we interpret to represent slab-edge melting of the Yakutat slab. A minor westward shift of volcanism within the SCVF at ca. 25 Ma was accompanied by continued subduction-related magmatism without the adakite-like component (i.e., mantle-wedge melting), represented by ca. 25–20 Ma basaltic-andesite to dacite domes and associated diorites. These eruptions were coeval with another westward shift to anhydrous, transitional-tholeiitic, basaltic-andesite to rhyolite lavas and tuffs of the ca. 23–19 Ma Sonya Creek shield volcano; we attribute these eruptions to intra-arc extension. SCVF activity was also marked by a small southward shift in volcanism at ca. 21 Ma, characterized by hydrous calc-alkaline lavas. SCVF geochemical compositions closely overlap those from the 10 m.y.).
机译：Sonya Creek Volcanic Field（SCVF）包含CA中最古老的原位火山产品。在阿拉斯加南部南部市中心的30毫安的Wrangell弧（WA）由于Yakutat微孔板俯冲开始而开始。 WA发生在Aleutian浏览到西部和右侧防滑构造的过渡带，沿着夏洛特 - 菲尔特和Denali-duke河断层系统到东部的夏洛特 - 菲尔特和Denali-Duke河断层系统。新的40 AR / 39 AR Beadrock的地理学表明，SCVF Magmatism发生从CA. 30-19 mA。新的田间映射，物理火山学和主要和微量元素地球化学，加上40架AR / 39 AR年龄和先前的侦察工作，允许重建SCVF岩浆演进。在加利福尼亚州开始的初始SCVF魔法师。 30 mA记录潮湿，俯冲相关，钙碱岩浆广场，以及我们解释yakutat平板的平滑熔化的adakite的组成部分。在加利福尼亚州SCVF内的火山中的次要向西转移。 25 mA伴随着持续的俯冲相关的岩浆，没有Adakite的组件（即披着楔形熔化），由CA代表。 25-20 mA玄武岩 - 粘土珠铁圆顶和相关的Diorites。这些爆发与另一个向西转移到无水，过渡 - 烟草，玄武岩 - 山脉的玄武岩和CA的凝灰岩。 23-19 MA Sonya Creek Shield Volcano;我们将这些爆发归因于ARC内扩展。 SCVF活动也标志着火山在加利福尼亚州的南方班次。 21 mA，其特征在于含水钙碱熔岩。 SCVF地球化学组合物紧密重叠10米。）。

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