Geochemical correlation of three large-volume ignimbrites from the Yellowstone hotspot track, Idaho, USA
Geochemical correlation of three large-volume ignimbrites from the Yellowstone hotspot track, Idaho, USA
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美国爱达荷州黄石热点轨迹的三种大体积熔结岩的地球化学对比
DOI：
10.1007/s00445-011-0510-z
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发表时间：
2011
影响因子：
3.5
通讯作者：
Ellis B
中科院分区：
文献类型：
--
作者：
Ellis B
在蛇河平原中部南缘发现了三种大量的流纹质褐斑岩。作为大范围对比的结果，可以对这些矿床做出新的体积估计：Steer盆地凝灰岩和美洲狮点凝灰岩XI约350亿千米3，美洲狮点凝灰岩XIII约1000千千米3。这些体积不包括任何相关的地区性火山灰和横跨平原北侧的相关性，这一点尚未尝试。每种对比都是利用野外测井、全岩和矿物化学、磁极、氧同位素特征和高精度40Ar/39Ar地质年代学等方法相结合的方法实现的。Steer盆地凝灰岩、美洲狮点凝灰岩XI和美洲狮点凝灰岩XIII具有典型的蛇河(SR)型火山作用的沉积特征：它们非常致密，强烈焊接，具有流变性，与稀有的浮岩和岩屑青金石分选得非常好。这些特征与黄石公园更知名的年轻喷发中的沉积物显著不同。这些沸石还表现出明显的δ18O亏损，这是蛇河平原中部SR型流纹岩的特征，累计代表800,000年内喷发的低δ18O流纹岩岩浆(长石值2.3-2.9‰)约1,700‰。我们的工作将蛇河平原中部已识别的褐煤总数减少了6个，改善了与黄石热点火山的灰烬记录的联系，并表明在这个双峰大火成岩省巨大的火山记录中，通过详细的对比工作，等待着发现更多的大容量褐煤。
Three voluminous rhyolitic ignimbrites have been identified along the southern margin of the central Snake River Plain. As a result of wide-scale correlations, new volume estimates can be made for these deposits: ~350 km3for the Steer Basin Tuff and Cougar Point Tuff XI, and ~1,000 km3for Cougar Point Tuff XIII. These volumes exclude any associated regional ashfalls and correlation across to the north side of the plain, which has yet to be attempted. Each correlation was achieved using a combination of methods including field logging, whole rock and mineral chemistry, magnetic polarity, oxygen isotope signature and high-precision40Ar/39Ar geochronology. The Steer Basin Tuff, Cougar Point Tuff XI and Cougar Point Tuff XIII have deposit characteristics typical of ‘Snake River (SR)-type’ volcanism: they are very dense, intensely welded and rheomorphic, unusually well sorted with scarce pumice and lithic lapilli. These features differ significantly from those of deposits from the better-known younger eruptions of Yellowstone. The ignimbrites also exhibit marked depletion in δ18O, which is known to characterise the SR-type rhyolites of the central Snake River Plain, and cumulatively represent ~1,700 km3of low δ18O rhyolitic magma (feldspar values 2.3–2.9‰) erupted within 800,000 years. Our work reduces the total number of ignimbrites recognised in the central Snake River Plain by 6, improves the link with the ashfall record of Yellowstone hotspot volcanism and suggests that more large-volume ignimbrites await discovery through detailed correlation work amidst the vast ignimbrite record of volcanism in this bimodal large igneous province.
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影响因子：
--
作者：
B. Jordan;A. Grunder;R. Duncan;A. Deino
通讯作者：
B. Jordan;A. Grunder;R. Duncan;A. Deino
影响因子：
4.9
作者：
G. Andrews;M. Branney
通讯作者：
G. Andrews;M. Branney
DOI：
10.1016/j.jvolgeores.2009.01.034
发表时间：
2009-11
影响因子：
2.9
作者：
W. Leeman;D. Schutt;S. Hughes
通讯作者：
W. Leeman;D. Schutt;S. Hughes
智利北部拉帕卡纳火山口：对世界上最大的复活火山口之一的地层学和火山学的重新评估
影响因子：
2.9
作者：
J. Lindsay;S. L. Silva;R. Trumbull;R. Emmermann;K. Wemmer
通讯作者：
K. Wemmer
影响因子：
3.7
作者：
D. Mark;D. Barfod;F. Stuart;J. Imlach
通讯作者：
D. Mark;D. Barfod;F. Stuart;J. Imlach