40Ar/39Ar ages and bulk-rock chemistry of the lower submarine units of the central and western Aleutian Arc
40Ar/39Ar ages and bulk-rock chemistry of the lower submarine units of the central and western Aleutian Arc
复制标题
阿留申岛弧中部和西部海底单元的 40Ar/39Ar 年龄和块体岩石化学
DOI：
10.1016/j.lithos.2021.106147
复制
发表时间：
2021
期刊：
影响因子：
3.5
通讯作者：
Turner, Simon
中科院分区：
文献类型：
--
作者：
Bezard, Rachel;Hoernle, Kaj;Pfänder, Jörg A.;Jicha, Brian;Werner, Reinhard;Hauff, Folkmar;Portnyagin, Maxim;Sperner, Blanka;Yogodzinski, Gene M.;Turner, Simon
为了进一步确定阿留申弧形成的时间及其早期演化，对来自深弧前峡谷和弧后构造的样品进行了阿留申海脊下部单元的大范围40Ar/39Ar测年和地球化学(常量和精选微量元素)活动(40个样品)。新的数据集略微提高了阿留申系统的最小起始年龄，最古老的两个样品的年龄分别为46.1±3.3 Ma和47.80±0.57 Ma。两个中始新世年龄都是在弧西段拉斑玄武岩基性火山岩上获得的。新的数据还支持在弧前第四纪演化期间(38-27 Ma、16-11 Ma和6-0 Ma)发生了三个不同的岩浆活动增强时期(岩浆脉冲)，这是以前根据更有限和主要是地面数据集提出的。此外，这些数据改进了第一次活动脉冲的持续时间，结束时间比之前的估计晚了2 Ma。第一个和最后一个脉冲可能与俯冲板块的旋转有关，而第二个脉冲可能是区域构造变化的结果。潜艇和水下样本的年龄分布之间的显著重叠表明，弧形的大部分早期部分可能已经被抬升并暴露在地下。与脉冲相关的预期地壳增长不太可能对岩浆停留时间产生重大影响，因为在脉冲期间或之后观察不到岩石分异程度的变化。另一方面，岩浆喷发的类型可能在弧形演化过程中发生了变化。在第一次脉冲之前，活动似乎主要是拉斑玄武岩。第一次脉动以同时代拉斑玄武岩、过渡岩浆和钙碱性岩浆为特征，在第一次~3 Ma后，钙碱性活动增强。随后，在29~8 Ma之间发生了一个以钙碱性为主的时期，随后拉斑玄武岩、过渡性拉斑玄武岩和钙碱性活动逐渐恢复。岩浆类型的这些时间变化对应于活动前缘下方弧形地壳厚度的可能变化，因此可能是对覆盖板块物理变化的响应。
In order to further constrain the timing of the Aleutian Arc initiation as well as its early evolution, an extensive40Ar/39Ar dating and geochemical (major and selected trace elements) campaign (40 samples) of the lower units of the Aleutian ridge has been carried out on samples dredged from deep fore-arc canyons and rear-arc tectonic structures. The new dataset slightly increases the minimum inception age for the Aleutian system, with the two oldest samples dated at 46.1 ± 3.3 Ma and 47.80 ± 0.57 Ma. Both mid Eocene ages were obtained on tholeiitic mafic volcanic rocks from the western section of the arc. The new data also support the occurrence of three distinct periods of enhanced magmatic activity (magmatic pulses) during the pre-Quaternary evolution of the arc (at 38–27, 16–11 and 6–0 Ma), as previously suggested based on a more limited and dominantly subaerial dataset. Moreover, the data refine the duration of the first pulse of activity, which ended 2 Ma later than previous estimates. The first and last pulses may be associated with rotations of the subducting plates while the second pulse might result from regional tectonic changes. The significant overlap between the age distribution of the submarine and subaerial samples suggests that much of the earlier parts of the arc may have been uplifted and subaerially exposed. The expected crustal growth associated with the pulses is unlikely to have significantly impacted magmatic residence times, since no variation in the degree of differentiation of the rocks can be observed during or after the pulses. On the other hand, the type of magmas erupted may have changed during the arc evolution. Prior to the first pulse, activity appears to have been dominantly tholeiitic. On the other hand, the first pulse was characterized by coeval tholeiitic, transitional and calc-alkaline magmas, with calc-alkaline activity increasing after the first ~3 Ma. Subsequently, a dominantly calc-alkaline period occurred from 29 to 8 Ma, followed by a progressive return of coeval tholeiitic, transitional and calc-alkaline activity. These temporal changes in magma types correspond to likely variations in arc crustal thickness beneath the active front, and could therefore be a response to physical changes of the overriding plate.
登录
查看更多内容
影响因子：
56.9
作者：
J. Tarduno;R. Duncan;D. Scholl;R. Cottrell;B. Steinberger;T. Thordarson;B. Kerr;C. Neal;F. Frey-F.
通讯作者：
J. Tarduno;R. Duncan;D. Scholl;R. Cottrell;B. Steinberger;T. Thordarson;B. Kerr;C. Neal;F. Frey-F.
西阿留申海底熔岩中的 Sr 和 O 同位素：对弧火山岩流体来源和微量元素特征的影响
DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
G. Yogodzinski;P. Kelemen;K. Hoernle;Shaun T. Brown;I. Bindeman;J. Vervoort;K. Sims;M. Portnyagin;R. Werner
通讯作者：
R. Werner
西阿留申群岛的岩浆和构造发育：走滑环境中的大洋弧
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
G. Yogodzinski;J. Rubenstone;S. Kay;R. Kay
通讯作者：
R. Kay
白令海鲍尔斯海岭 IODP 孔 U1342A 和 D 中发现的火山岩的 40 Ar- 39 Ar 测年及其构造意义
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
Keiko Sato;H. Kawabata;D. Scholl;H. Hyodo;Kozo Takahashi;Katsuhiko Suzuki;H. Kumagai
通讯作者：
H. Kumagai
阿留申岛弧德拉罗夫群岛始新世至更新世岩浆演化
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
A. Schaen;B. Jicha;S. Kay;B. Singer;A. Tibbetts
通讯作者：
A. Tibbetts