The Blacktail Creek Tuff: an analytical and experimental study of rhyolites from the Heise volcanic field, Yellowstone hotspot system
The Blacktail Creek Tuff: an analytical and experimental study of rhyolites from the Heise volcanic field, Yellowstone hotspot system
复制标题
黑尾溪凝灰岩：黄石热点系统海斯火山场流纹岩的分析和实验研究
DOI：
10.1007/s00410-015-1112-0
复制
发表时间：
2015
影响因子：
3.5
通讯作者：
Nash B.
中科院分区：
文献类型：
--
作者：
Bolte T;Holtz F;Almeev R;Nash B.
采用温压和实验相结合的方法，对黄石热点系黑泽火山场(6.62~4.45 Ma)6.62 Ma黑尾溪凝灰岩喷发的岩浆储存条件进行了研究。不同的地质温度计(如Fe-Ti氧化物、长石对、磷灰石和锆石的溶解度以及石英中的钛)的结果表明，喷发前的温度在825-875℃之间。用两对辉石估计的温度在810-950℃的范围内变化，但辉石可能彼此不平衡，辉石中熔体包裹体的分析结果表明，单斜辉石具有复杂的历史，它含有两种成分不同的包裹体类型。一个天然的黑尾溪凝灰岩样品被用来实验测定压力在100-500兆帕和水活度在0.1-1.0范围内的平衡相组合。这些实验是在有流体的条件下进行的，流体相由H2O和CO2组成，以及在没有流体的条件下进行。在两种类型的实验中，石英长石相的稳定性是相似的，但是否存在镁铁质矿物，如黑云母和单斜辉石，强烈依赖于实验方法。对这种差异给出了可能的解释，这种差异可能会对确定岩浆储存条件的适当实验方法的选择产生强烈的影响。通过比较天然相和实验合成相的组成，确定了岩浆的储存温度为845-875℃。在此温度下，需要含有1.5-2.5wt%H2O的熔融水才能再现天然的黑尾溪凝灰岩矿物组合。利用石英中钛的气压计和与石英、斜长石、辉长岩共生的天然基质玻璃的QZ-Ab-或比例，估计岩浆储存深度在130-250 Mpa的压力范围内。
The magma storage conditions of the 6.62 Ma Blacktail Creek Tuff eruption, belonging to the Heise volcanic field (6.62–4.45 Ma old) of the Yellowstone hotspot system, have been investigated by combining thermobarometric and experimental approaches. The results from different geothermometers (e.g., Fe–Ti oxides, feldspar pairs, apatite and zircon solubility, and Ti in quartz) indicate a pre-eruptive temperature in the range 825–875 °C. The temperature estimated using two-pyroxene pairs varies in a range of 810–950 °C, but the pyroxenes are probably not in equilibrium with each other, and the analytical results of melt inclusion in pyroxenes indicate a complex history for clinopyroxene, which hosts two compositionally different inclusion types. One natural Blacktail Creek Tuff rock sample has been used to determine experimentally the equilibrium phase assemblages in the pressure range 100–500 MPa and a water activity range 0.1–1.0. The experiments have been performed at fluid-present conditions, with a fluid phase composed of H2O and CO2, as well as at fluid-absent conditions. The stability of the quartzo-feldspathic phases is similar in both types of experiments, but the presence of mafic minerals such as biotite and clinopyroxene is strongly dependent on the experimental approach. Possible explanations are given for this discrepancy which may have strong impacts on the choice of appropriate experimental approaches for the determination of magma storage conditions. The comparison of the composition of natural phases and of experimentally synthesized phases confirms magma storage temperatures of 845–875 °C. Melt water contents of 1.5–2.5 wt% H2O are required to reproduce the natural Blacktail Creek Tuff mineral assemblage at these temperatures. Using the Ti-in-quartz barometer and the Qz–Ab–Or proportions of natural matrix glasses, coexisting with quartz, plagioclase and sanidine, the depth of magma storage is estimated to be in a pressure range between 130 and 250 MPa.
登录
查看更多内容
从大型分异岩浆房中快速提取离散岩浆批次：怀俄明州黄石火山口的中央高原段流纹岩
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
G. Girard;J. Stix
通讯作者：
J. Stix
影响因子：
3.1
作者：
Whitney, Donna L.;Evans, Bernard W.
通讯作者：
Evans, Bernard W.
韦尔托安山岩（科罗拉多州圣胡安火山田鱼峡谷系统）喷发前条件：挥发物 (C–O–H–S) 对相平衡和矿物成分的影响
影响因子：
3.9
作者：
F. Parat;F. Holtz;S. Feig
通讯作者：
S. Feig
影响因子：
3.5
作者：
B. Ellis;T. Barry;M. Branney;John A. Wolff;I. Bindeman;Rob Wilson;B. Bonnichsen
通讯作者：
B. Ellis;T. Barry;M. Branney;John A. Wolff;I. Bindeman;Rob Wilson;B. Bonnichsen
美国西部爱达荷州斯内克河平原海斯火山场的时间和发育
影响因子：
4.9
作者：
L. Morgan;W. Mcintosh
通讯作者：
W. Mcintosh