Did melting glaciers cause volcanic eruptions in eastern California? Probing the mechanics of dike formation
Did melting glaciers cause volcanic eruptions in eastern California? Probing the mechanics of dike formation
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DOI：
10.1029/2004jb002978
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发表时间：
2004-09-21
影响因子：
3.9
通讯作者：
Saar, MO
中科院分区：
文献类型：
--
作者：
Jellinek, AM;Manga, M;Saar, MO
[1] 将过去 400 kyr 期间加利福尼亚州东部玄武岩和硅质喷发的时间序列与同期全球冰川作用记录进行比较表明，这种火山活动受到大约 40 kyr 期间发生的冰川生长和退缩的影响。喷发频率的变化与冰川时间序列的一阶导数之间具有统计学上显着的互相关性，这意味着火山活动的时间模式受到冰体积变化率的影响。此外，计算出的冰川卸荷对硅质和玄武质火山作用影响的时滞是不同的，分别为 3.2 +/- 4.2 kyr 和 11.2 +/- 2.3 kyr。开发了一个理论模型来研究冰川卸载期后喷发频率的增加是否是最终由岩脉形成动力学控制的响应。反过来，应用时间序列分析的结果可以估计喷发所需的临界岩浆室超压以及控制岩脉传播的围岩有效粘度的约束。
[1] A comparison of time series of basaltic and silicic eruptions in eastern California over the last 400 kyr with the contemporaneous global record of glaciation suggests that this volcanism is influenced by the growth and retreat of glaciers occurring over periods of about 40 kyr. Statistically significant cross correlations between changes in eruption frequency and the first derivative of the glacial time series imply that the temporal pattern of volcanism is influenced by the rate of change in ice volume. Moreover, calculated time lags for the effects of glacial unloading on silicic and basaltic volcanism are distinct and are 3.2 +/- 4.2 kyr and 11.2 +/- 2.3 kyr, respectively. A theoretical model is developed to investigate whether the increases in eruption frequency following periods of glacial unloading are a response ultimately controlled by the dynamics of dike formation. Applying results from the time series analysis leads, in turn, to estimates for the critical magma chamber overpressure required for eruption as well as constraints on the effective viscosity of the wall rocks governing dike propagation.