...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Geological Society of America Bulletin >Tectonic and chronostratigraphic implications of new ~(40)Ar/~(39)Ar geochronology and geochemistry of the Arman and Maltan-Ola volcanic fields,Okhotsk-Chukotka volcanic belt,northeastern Russia
【24h】

Tectonic and chronostratigraphic implications of new ~(40)Ar/~(39)Ar geochronology and geochemistry of the Arman and Maltan-Ola volcanic fields,Okhotsk-Chukotka volcanic belt,northeastern Russia

机译：俄罗斯东北部鄂霍次克-楚科奇火山带阿尔曼和马尔他-奥拉火山新〜（40）Ar /〜（39）Ar地球年代学和地球化学的构造和年代地层意义

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Okhotsk-Chukotka volcanic belt is part of an extensive late Early to Late Cretaceous Andean-style magmatic arc that spans the entire eastern margin of the Asian continent.The belt itself stretches 3000 km from the Chukotka Peninsula to the Uda River and comprises approx 1.2x10~6 km~3 of volcanic rock over a 500,000 km~2 area.Despite its size and regional tectonic significance,the time span of magmatic activity is poorly constrained and the subject of significant debate,mostly in the Russian literature.In this paper,we provide new geochronologic control on the timing of inception and cessation of magmatism for the Arman and Maltan-Ola volcanic fields.These field localities were chosen because they are well studied,relatively accessible,and contain floral assemblages that have been used to correlate volcanic sequences at the regional scale.The majority of the volcanic sequence was emplaced between 85.5 +-1.3 Ma and 74.0+-1.2 Ma,as shown by 17 new ~(40)Ar/~(39)Ar ages.The Coniacian-Santonian to Campanian age range indicated is 15 m.y.younger than the Albian to early Cenomanian age range given by a synthesis of floral stratigraphic,K-Ar,and Rb-Sr geochronologic data.The calc-alkaline part of the volcanic section spans an apparent age range of 85.5+-1.3 Ma to 80.7+-0.8 Ma.Capping basalts were emplaced between 77.5+-1.1 Ma and 74.0+-.2 Ma and exhibit a within-plate geochemical signature,which we attribute to a temporally and geochemically distinct,possibly extension-related,phase of magmatism.The apparent northwestward migration of the arc front from the interior (seaward) zone (Taigonos Peninsula,Magadan batholith) in Albian-Cenomanian time to the Arman and Maltan-Ola volcanic fields in Coniacian-Santonian to Campanian time may be explained by shallowing of the subducting paleo-Pacific (Kula?) oceanic plate.The flat-lying nature of these volcanic rocks and the within-plate geochemical affinity of the capping basalt unit are inconsistent with prevailing tectonic models for the cessation of arc magmatism and formation of the Sea of Okhotsk which require the collision of a microcontinental block or oceanic plateau with the northeast Asian margin in the Late Cretaceous.
机译：鄂霍次克-楚科奇火山火山带是横跨亚洲大陆整个东部边缘的早白垩纪晚期至晚白垩纪安第斯式岩浆弧的延伸部分，该带本身从楚科奇半岛一直延伸到乌达河约3000公里。在500,000 km〜2范围内有x10〜6 km〜3的火山岩。尽管它的大小和区域构造意义，但岩浆活动的时间跨度受限制很有限，并且是值得争论的主题，主要是在俄罗斯文学中。我们为Arman和Maltan-Ola火山岩的成岩和停止岩浆作用的时间提供了新的地质年代学控制。选择这些油田地点是因为它们研究得很好，相对容易到达，并且包含用来与火山相关的花卉组合。火山喷发的大部分位于85.5 + -1.3 Ma至74.0 + -1.2 Ma之间，如17个新的〜（40）Ar /〜（39）Ar年龄所示。通过花地层，K-Ar和Rb-Sr年代学资料综合得出的结果表明，牛顿至坎帕尼亚年龄范围比阿尔比至早塞诺曼尼亚年龄范围年轻15 myyoung。火山段的钙碱性部分跨越一个明显的年龄。范围为85.5 + -1.3 Ma至80.7 + -0.8 Ma。封盖玄武岩放置在77.5 + -1.1 Ma和74.0 +-。2 Ma之间，并显示出板内地球化学特征，这归因于时间和地球化学的不同，弧线锋从阿尔比-西诺马尼亚时期的内部（向海）区域（塔戈诺斯半岛，马达加丹岩床）向阿尔曼和马尔科-桑托尼亚的阿尔塔火山和马尔他-奥拉火山油田向西北的明显迁移。寒武纪时间可以用俯冲古太平洋洋板的浅化来解释。这些火山岩的平坦性和封盖玄武岩单元的板内地球化学亲和力与普遍的构造模型不一致。这是为了停止弧岩岩浆作用和鄂霍次克海的形成，这需要一个微大陆块或海洋高原与白垩纪晚期的东北亚边缘碰撞。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号