Preliminary Results on the Post-impact Hydrothermal Alteration in the Yaxcopoil-1 Hole, Chicxulub Impact Structure, Mexico

Introduction: The results presented here are part of an investigation into the evolution of hydrothermal events associated with the Chicxulub impactites in Yu-catan, Mexico. The study focuses on alteration products in core samples recovered from the Yaxcopoil-1 drill hole, which is located some 60 kilometers from the center of the impact structure. This research contributes to the growing knowledge-base of post-impact hydrothermal systems [e.g. 1, 2] and their importance as potential life-originating environments [3]. Macro-scopic and petrographic descriptions, as well as preliminary electron microprobe and RAMAN spectrome-try analyses, thus far, indicate a systematic spatial and temporal distribution of hydrothermal products in the Yaxcopoil-1 core. Protolith: To understand the sequence of replacement by hydrothermal products it was necessary to assess the original mineralogy of the altered proto-lith. At the Yaxcopoil-1 site, a green melt unit is composed of microcrystalline plagioclase, clinopyroxene, K feldspar, and a silicate phase, potentially glass, that has been pervasively replaced by phyllosilicates. Cli-nopyroxenes contain a small fraction of sodium (Aeg 1