Despite the common occurrence of heterogeneous andesitic eruptions, few studies have investigated the compositional effects on microlite crystallization and vesiculation in co-erupted natural samples. In 2006, Augustine Volcano erupted compositionally heterogeneous andesites that range from 56.4 to 63.3 wt% SiO₂ and include two endmember lithologic groups: low-silica andesite (LSA) and high-silica andesite (HSA). Textural and compositional differences between LSA and HSA end members are explored for two discrete, sequential vulcanian explosions from January 17 (event 9) and 27 (event 10), 2006. Groundmass glass compositions of pyroclasts within LSA and HSA compositional suites are not colinear and do not correlate with plagioclase microlite crystallinities, indicating eruption from multiple isolated shallow magma reservoirs with various pressure-temperature pathways. HSA pyroclasts have lower crystallinities, 0.02–0.24, than most LSA pyroclasts, 0.16–0.39, demonstrating the influence of composition on crystallinity. Additionally, microlite textural and groundmass glass compositional differences exist between consecutive vulcanian explosions. The event 9 deposits have a typical bimodal density distribution and groundmass glass compositions range from 65 to 78 wt% SiO₂. Plagioclase microlite number densities (MN_V) are 10^4.6–6.4 mm⁻³ and crystallinities are 0.02 to 0.28, similar to products from other andesitic vulcanian eruptions. Deposits from the early phase of event 10 have a bimodal density distribution and contain a high proportion of LSA pyroclasts, similar to event 9. Groundmass glass compositions range from 72 to 79 wt% SiO₂ and plagioclase MN_V are 10^5.9–6.3 mm⁻³, forming narrower ranges compared to event 9. A transition occurred during the later phase of event 10 to a unimodal density distribution, a more homogeneous groundmass glass composition, 75–78 wt% SiO₂, a higher proportion of HSA pyroclasts, and the highest MN_V of 10^5.9–6.7 mm⁻³. We interpret this shift to reflect eruption from reservoir depths around 4–6 km and the cessation of pre-eruptive magma staging in the upper conduit, transitioning the eruption to continuous and effusive phases. Attention to heterogeneous andesitic erupted products reveals additional details about heterogeneous shallow magma storage, variable upper conduit magma staging, and a range of pressure-temperature paths prior to fragmentation.

尽管异质安第斯火山喷发普遍发生，但很少有研究调查了共生天然样品对微晶结晶和囊泡形成的影响。2006年，Augustine火山喷发了组成范围为56.4至63.3 wt％SiO _2的成分不均匀的安山岩。包括两个端基岩性组：低硅质安山岩（LSA）和高硅质安山岩（HSA）。从2006年1月17日（事件9）和27（事件10）开始，对两个离散的连续伏尔加斯爆炸进行了探索，研究了LSA和HSA末端成员之间的组织和成分差异。与斜长石微晶的结晶度无关，表明从多个具有不同压力-温度路径的孤立浅岩浆储层喷发。HSA火山碎屑的结晶度较低，为0.02–0.24，而大多数LSA火山碎屑的结晶度为0.16-0.39，这说明了成分对结晶度的影响。此外，连续的伏尔加斯爆炸之间存在微晶质感和地面质量的玻璃成分差异。₂。斜长石微晶数密度（MN _V）为10 ^4.6–6.4  mm ^-3，且结晶度为0.02至0.28，与其他安第斯山火山喷发的产物相似。从事件10的早期阶段沉积物具有双峰密度分布和包含LSA火山碎屑，类似于事件9. Groundmass玻璃组合物的范围从72至79的高比例重量％的SiO ₂和斜长石MN _V是10 ^5.9-6.3 毫米^{-如图3所示}，与事件9相比，形成的射程更窄。在事件10的后期发生了过渡到单峰密度分布，更均匀的地面质量玻璃成分，75–78 wt％的SiO ₂，较高比例的HSA^破骨细胞和最高的MN _V为10 ^5.9–6.7  mm ^-3。我们将这一解释解释为反映了储层深度约4-6 km的喷发以及上导管中喷发前岩浆阶段的停止，从而使喷发过渡到连续和喷发阶段。对异质安第斯火山喷发产品的关注揭示了有关异质浅岩浆储存，可变上部导管岩浆分级以及破碎前压力温度路径范围的更多细节。