El´gygytgyn impact structure, Siberia: Investigation of a mid-size impact structure in volcanic target.

年轻的（3.6 Ma），直径18公里的El ' gygytgyn陨石坑位于俄罗斯东北部的楚科奇，是地球上保存最完好的撞击结构之一。这个复杂的陨石坑结构是在一个硅质火山目标中形成的，这使得它与其他行星表面（例如火星上）火山中丰富的撞击结构相当。撞击后形成了一个火山口湖，在这个火山口湖内，未受干扰的持续湖泊沉积形成了一个连续的、长期的古环境信息库。这个陨石坑从未被冰川或冰盖覆盖，这使得一个独特的北极气候档案得以发展。2009年春季，“国际大陆钻探项目（ICDP）”的一次钻探活动恢复了一个完整的（517米）湖泊沉积物和撞击物序列（317米的湖泊，撞击后沉积物，几米宽的过渡带到下面的撞击角砾岩-在170米的单一岩屑角砾岩之上25米的浮石）。钻探的目的是：(1)收集北极陆地气候历史上前所未有的记录；(2)在罕见的地质环境中促进对这种独特撞击结构的火山口填充和火山口底部地质的研究。在这里，我们提出了一个岩石学（包括冲击变形）和化学（包括弹丸识别）项目，旨在阐明该岩心中冲击序列的形成，并结合基于这些结果的数值模拟（在第二阶段），以更好地理解产生这种复杂冲击结构所涉及的冲击过程。

The young (3.6 Ma), 18 km diameter El´gygytgyn crater in Chukotka, NE Russia, is one of the best-preserved impact structures on Earth. The complex crater structure was formed in a silicious volcanic target, which makes it a rare terrestrial equivalent to the abundant impact structures in volcanics on other planetary surfaces (e.g., on Mars). After the impact a crater lake formed – within which undisturbed and continued lacrustrine sedimentation took place to establish a continuous, long-term reservoir of paleoenvironmental information. The crater was never covered by glaciers or ice shields, which allowed the development of a unique arctic climate archive. In spring 2009 a drilling campaign by the “International Continental Drilling Project (ICDP)” recovered a complete (517 m) sequence of lake sediments and impactites (317 m of lacustrine, post-impact sediments, a several m wide transition zone to the underlying impact breccias - 25 m suevite above 170 m monomict lithic breccia). The goals for drilling were: (1) to collect an unprecedented record of climate history in the terrestrial arctic, and (2) to facilitate study of the crater fill and the crater floor geology of this unique impact structure in a rare geological setting. Here we propose a petrographic (incl. shock deformation) and chemical (incl. projectile identification) project aimed at elucidating the formation of the impactite sequence in this drill core, and – in conjunction with numerical modeling based on these results (during phase 2) – at a better understanding of the impact processes involved in generation of this complex impact structure.