Louisville Seamount Chain: Petrogenetic processes and geochemical evolution of the mantle source
Louisville Seamount Chain: Petrogenetic processes and geochemical evolution of the mantle source
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DOI：
10.1002/2014gc005288
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发表时间：
2014-06
期刊：
影响因子：
3.7
通讯作者：
L. Vanderkluysen;J. Mahoney;A. Koppers;C. Beier;M. Regelous;J. Gee;P. Lonsdale
中科院分区：
文献类型：
--
作者：
L. Vanderkluysen;J. Mahoney;A. Koppers;C. Beier;M. Regelous;J. Gee;P. Lonsdale
路易斯维尔海山链（英语：Louisville Seamount Chain）是位于太平洋西南部的一条4300公里长的海底火山链，其年龄范围与夏威夷-皇帝火山链相当，通常被认为是热点轨迹。2006年的疏浚从22座海山的33个站点回收了火成岩，覆盖了该岛链约4900万年的历史。所有样品都是碱性的，类似于以前的挖掘和钻探样品，没有提供夏威夷型拉斑玄武岩盾火山阶段的证据。主要和微量元素的变化似乎主要是由小，但不同程度的分离结晶和部分熔融控制。同位素值仅定义了一个狭窄的范围，与令人惊讶的长期源丰度一致-相对于熔融的长度尺度-并与“C”和“FOZO”地幔端元的拟议字段重叠。微量元素和同位素地球化学是不相关的海山年龄或岩石圈厚度在火山活动时，除了少量的熔岩从最西端的路易斯维尔海山建立在年轻的（<20 Ma）的洋壳。路易斯维尔热点被假定为120 Ma Ontong Java Plateau的来源，但路易斯维尔的同位素特征不可能是从一个同位素比像Ontong Java Plateau玄武岩那样的来源演化而来的。另一方面，这一特征可以与从马尼希基高原的危险群岛海槽中挖掘出的样本相关联，该海槽被解释为“大”翁通爪哇高原的断裂碎片。
The Louisville Seamount Chain is a ∼4300 km long chain of submarine volcanoes in the southwestern Pacific that spans an age range comparable to that of the Hawaiian‐Emperor chain and is commonly thought to represent a hot spot track. Dredging in 2006 recovered igneous rocks from 33 stations on 22 seamounts covering some 49 Myr of the chain's history. All samples are alkalic, similar to previous dredge and drill samples, providing no evidence for a Hawaiian‐type tholeiitic shield‐volcano stage. Major and trace element variations appear to be predominantly controlled by small but variable extents of fractional crystallization and by partial melting. Isotopic values define only a narrow range, in agreement with a surprising long‐term source homogeneity—relative to the length scale of melting—and overlap with proposed fields for the “C” and “FOZO” mantle end‐members. Trace element and isotope geochemistry is uncorrelated with either seamount age or lithospheric thickness at the time of volcanism, except for a small number of lavas from the westernmost Louisville Seamounts built on young (<20 Ma old) oceanic crust. The Louisville hot spot has been postulated to be the source of the ∼120 Ma Ontong Java Plateau, but the Louisville isotopic signature cannot have evolved from a source with isotopic ratios like those measured for Ontong Java Plateau basalts. On the other hand, this signature can be correlated with that of samples dredged from the Danger Islands Troughs of the Manihiki Plateau, which has been interpreted as a rifted fragment of the “Greater” Ontong Java Plateau.