Lithostratigraphy and Palagonitization of a Glaciovolcanic Tephra Cone, Undirhlíðar Ridge, Southwest Iceland

• Main Author: Reynolds, Ric
• Format: Text
• Language: English; unknown
• Published: Open Works 2019
• Subjects: Palagonite; Glaciovolcanism; Tindar; Tuya; Earth Sciences; Smellie; The Gully; Undirhlíðar; Iceland
• Online Access: https://openworks.wooster.edu/independentstudy/8489; https://openworks.wooster.edu/context/independentstudy/article/11380/viewcontent/Independent_Study_FINAL.pdf

This study is a continuation of the 2016 Keck Geology Consortium project at Undirhlíđar Ridge located in Southwest Iceland. This study looks at the percentage of palagonitization in eleven samples along Undirhlíđar Ridge and focuses on describing the lithostratigraphy and palagonitization in an area previously mapped as tephra deposits. This section is a large portion of the ridge and is composed of mainly hyaloclastite deposits. After sample collection it was determined that they are less palagonitized than previous studies. This research looks to understand palagonite alteration at Undirhlíđar by applying conclusions from other palagonite analyses (Stroncik and Schmincke, 2001; Stroncik and Schmincke, 2002; Jakobsson and Moore, 1986; Smellie and Edwards, 2016) The samples collected here indicate multiple eruptive events, a range of palagonitization with high amounts near the north-eastern flank and lesser amounts on the south-western flank (specifically in the gully), and there is a spatial difference that may indicate mass movements after the eruption subsided and glacial retreat commenced. In addition to the results presented in this study, the map from Lembo and Cheney (2017) was updated with new units and lithostratigraphy. The lab techniques for this study were completed in following the procedures of (Pollock et al., (2014). Thin section photomicrographs were taken of all samples to conduct an ImageJ spatial analysis for palagonite, glass, and other compositions in order to plot and compare samples on a ternary diagram.