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位于奇瓦瓦州东部墨西哥盆岭省的埃尔维龙仑脱山,由厚度超过700米的硅质高钾钙碱性灰流凝灰岩组成,年龄为33.7±0.3到29.5±0.5m.y.。凝灰岩的斑晶至少70%为环带长石,其核心为中长石,边部为歪长石。次要的斑晶有单斜辉石、黑云母、钛铁矿、磁铁矿、透长石、角闪石、石英、斜方辉石。辉石富Mg,并且有一定的Mg-Fe比范围。Fe-Ti氧化物在高温(880～1055℃),高氧逸度(-lgfO_2=8.3～11.0)下平衡。凝灰岩强烈富集轻稀土元素(LREE),中等强度负Eu异常。87Sr/86Sr初始比为0.7043～0.7065,与SiO_2、Sr、Rb/Sr略显相关性。Sr同位素组成
The Elvonlung off-hill, located in the province of Peloton in the eastern province of Chihuahua, consists of siliceous high-K calc-alkaline gray tuffs more than 700 meters in thickness, ranging in age from 33.7 ± 0.3 to 29.5 ± 0.5 m.y. At least 70% of the tuff crystals are feldspar feldspar, the center of the feldspar, the edge of crooked feldspar. The secondary plaques are clinopyroxene, biotite, ilmenite, magnetite, metformin, hornblend, quartz, orthopyroxene. Pyroxene is rich in Mg and has a certain range of Mg-Fe ratios. Fe-Ti oxide is balanced at high temperature (880 ~ 1055 ℃) and high oxygen fugacity (-lgfO_2 = 8.3 ~ 11.0). Tuff strongly enriched LREE and moderate-intensity negative Eu anomaly. The initial ratio of 87Sr / 86Sr is 0.7043 ~ 0.7065, which is slightly related to SiO_2, Sr, Rb / Sr. Sr isotope composition