Characterizing the geologic setting of popping rocks: Preliminary results from the 2018 Popping Rocks cruise to the Mid-Atlantic Ridge
Abstract
The popping rocks discovered in a dredge in 1985 aboard the R/V Akademik Boris Petrov at 13° 46' N along the Mid-Atlantic Ridge (MAR) have been used as a possible reference for mantle volatile abundances. To determine the abundance and distribution of popping rocks on the seafloor and evaluate the processes that contribute to popping rocks formation we sampled and explored the popping rocks MAR area on R/V Atlantis cruise AT33-03 (Popping Rocks 2016) and R/V Atlantis cruise AT40-02 (Popping Rocks 2018). During Popping Rocks 2018 we conducted a total of 18 HOV Alvin dives, 17 AUV Sentry dives, and collected 285 rock samples, 69 push cores, and 8 gravity cores. The combination of Sentry mapping and Alvin sampling allowed the delineation of popping rock occurrence on the N-S trending "Popping Rock Ridge" (PRR) and the valley walls to the east. We collected a total of 45 popping rock samples and created a 32 km2 high-resolution map centered on the popping rocks occurrence. To place the popping rocks in a broader geologic context, Sentry mapped an additional 40 km2 along three, two-kilometer-wide transects of the MAR ridge between 13° 48' N and 14° 05' N, making this one of the best characterized slow-spreading segments to date. Across-axis transects were obtained (1) near the center of the magmatic segment (14° 4.62'), (2) at the latitude of an Oceanic Core Complex (OCC, at 13° 48.6'), and (3) at a transitional region between these two tectonic settings (13° 56' N). No popping rocks were found at any of these sites, demonstrating that occurrence is limited to the area around the PRR. Based on seafloor morphology, lithology (aphyric basalt), vesicularity, and homogeneous geochemistry, we hypothesize that PRR was formed by a single eruption/eruptive event, but that additional popping rocks eruptions may have occurred on the eastern valley walls. Data analysis is ongoing and an update will be given at the meeting.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.V52B..06M
- Keywords:
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- 0450 Hydrothermal systems;
- BIOGEOSCIENCESDE: 4825 Geochemistry;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 8416 Mid-oceanic ridge processes;
- VOLCANOLOGYDE: 8424 Hydrothermal systems;
- VOLCANOLOGY