Extraction of high-silica granites from an upper crustal magma reservoir: Insights from the Narusongduo magmatic system, Gangdese arc
Extraction of high-silica granites from an upper crustal magma reservoir: Insights from the Narusongduo magmatic system, Gangdese arc
复制标题
从上地壳岩浆库中提取高硅花岗岩：冈底斯弧那如松多岩浆系统的见解
DOI：
10.2138/am-2020-7369
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发表时间：
2020-10
影响因子：
3.1
通讯作者：
Wyman Derek A
中科院分区：
文献类型：
--
作者：
Zhou Jin-Sheng;Yang Zhu-Sen;Wang Qiang;Zheng Yuan-Chuan;Hou Zeng-Qian;Wyman Derek A
摘要高硅质火成岩的成因对于认识浅部岩浆系统的行为具有重要意义。然而，尽管许多这样的研究集中在低结晶高SiO2流纹岩的喷发，高硅花岗岩（HSG）的起源得到了相对较少的关注。本文对冈底斯弧那如松多火山杂岩中的HSG进行了详细的研究。结合锆石U-Pb年代学和地层学研究，我们认为那如松多岩浆系统的形成经历了≥ 370万年的时间，有或没有间歇期。根据锆石的结构和年龄，不同的锆石人口，包括前晶和自晶，被识别出的HSG和火山岩。纳如松多火山杂岩的岩浆岩均具有高放射成因的Sr-Nd同位素组成。我们的结果表明，在古深度约8公里的上地壳中存在安山质岩浆库。HSG中普遍存在的锆石前晶，结合HSG与安山质岩浆库演化熔体之间的成分相似性，表明纳如松多HSG代表从浅岩浆库中提取的熔体。此外，我们的研究结果表明，岩浆补给促进了高硅熔体的逃逸，形成纳如松多HSG。这一工作为大规模高硅花岗岩是上地壳岩浆库分异产物提供了极好的例证。它将有助于当代关于上地壳岩浆系统中晶体-熔体分离效率的辩论。
Abstract The genesis of high-silica igneous rocks is important for understanding the behavior of shallow magmatic systems. However, although many such studies have focused on the eruption of crystal-poor high-SiO2 rhyolites, the origin of high-silica granites (HSGs) has received comparatively little attention. Here, we present a detailed study of HSGs from the Narusongduo volcanic complex, Gangdese arc. Combining zircon U-Pb geochronology with stratigraphic investigations, we show that the Narusongduo magmatic system was constructed over a period of ≥3.7 Myr with or without lulls. On the basis of zircon textures and ages, diverse zircon populations, including antecrysts and autocrysts, are recognized within the HSGs and volcanic rocks. All of the igneous rocks within the Narusongduo volcanic complex have highly radiogenic Sr–Nd isotopic compositions. Our results indicate the presence of an andesitic magma reservoir in the upper crust at a paleodepth of ~8 km. Ubiquitous zircon antecrysts in the HSGs, combined with compositional similarities between the HSGs and evolved melts of the andesitic magma reservoir, indicate that the Narusongduo HSGs represent melts extracted from the shallow magma reservoir. In addition, our results suggest that magma recharge promoted the escape of high-silica melts to form the Narusongduo HSGs. This work presents an excellent case that kilometer-scale high-silica granites are the differentiated products from an upper crustal magma reservoir. It would make a contribution to contemporary debates concerning the efficiency of crystal–melt separation in upper crustal magmatic systems.
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影响因子：
3.9
作者：
Calvin G. Barnes
通讯作者：
Calvin G. Barnes
影响因子：
3.7
作者：
D. Weis;B. Kieffer;C. Maerschalk;W. Pretorius;J. Barling
通讯作者：
D. Weis;B. Kieffer;C. Maerschalk;W. Pretorius;J. Barling
DOI：
10.1017/s0263593300014279
发表时间：
1988
影响因子：
1.2
作者：
P. Lipman
通讯作者：
P. Lipman
西藏拉萨南部的古新世（约 62 Ma）淡色花岗岩：板块回滚过程中同碰撞地壳深熔的产物？
影响因子：
3.9
作者：
Ma Lin;Wang Qiang;Kerr Andrew C.;Yang Jin-Hui;Xia Xiao-Ping;Ou Quan;Yang Zong-Yong;Sun Peng
通讯作者：
Sun Peng
影响因子：
3.5
作者：
B. Wood;J. Blundy
通讯作者：
B. Wood;J. Blundy