ILUMETSA POTENTIAL IMPACT STRUCTURE AS AN ODESSA-TYPE CRATER.

摘要: Introduction: Odessa-type crater was proposed to be one of the principal structural types of small impact craters [1]. These are characterized by having anticlines (sometimes with truncated tops) within the crater inner rim, locally displaced along inward-dipping faults [1, 2]. This study aims to document structures within the inner slope of the Ilumetsa Large (IL) potential impact structure in order to compare them to nearby undeformed sedimentary target and known Odessa-type small impact craters on Earth. Study site: Ilumetsa in SE Estonia consists of two rimmed structures 80 m and~ 50 m in diameter, located 725 m from each other [3] and 7 ka old [4]. The target consisted of a~ 0.5-1 m of limno-glacial sands, a couple of meters of glacial till, and Middle Devonian weakly lithified sandstone at 2-4 m depth. Undisturbed sandstone is usually crossbedded, and often consist of 20-30 cm white sets dividied by 5-10 cm …