EVA Report #05
Author: Eshaana Aurora
EVA Date: 28th December 2023
Start time: 1105
End time: 1329
Purpose of EVA:
Collection of Oyster Fossils to Sample Western Interior Seaway Shelf Deposits
Narrative:
The Extra-Vehicular Activity (EVA) commenced at 1105, led by Adriana, with the participation of Eshaana (Crew Geologist), Nathan (Crew Engineer) and Sara (Crew Journalist). The crew embarked on their Martian exploration utilizing the Spirit and Curiosity rovers, navigating from Cow Dung Road to the south until reaching Kissing Camel Ridge and then headed southwest until a quarter mile away from Zubrin’s head. Spirit and Curiosity initiated the mission with full charges – Spirit at 100% and 239.6 hours, Curiosity at 100% and 262.0 hours. The crew’s primary objective was to search for and collect samples of oyster fossils within the Tununk shale layer of the Martian terrain while navigating in EVA suits. This was the second chosen location for the oyster sampling.
Throughout the mission, the crew captured vivid photos and delved into the local geology, leading to the discovery of multiple bentonite beds which are extremely relevant geological time markers. With respect to oyster fossils, the chosen location did not seem to contain any despite having relatively the same stratigraphy and facies, including the dark gray layer discovered in EVA#04. However, the crew continued to take in the beautiful Martian rock formations and views, nonetheless. The crew initially stopped at a location that comprised the remnants of Dakota sandstone then moved up through the Tununk shale finally ending in the Ferron sandstone layer, which was a white to tan colored, quartz rich, top layer. This was the same quartz sand that we found during EVA #04 with a fine to medium grain size which was poorly consolidated.
Additionally, on the walk to Barrainca Butte the crew spotted extensive amounts of pebble to cobble sized chert. The crew also discovered some reddish beds which were poorly lithified and could perhaps be a subsequence in the Tununk Shale layer therefore the crew was able to witness the gradual switch between rich sandstone to clay like mudstone layers quite comprehensively. The major observation, however, was the bentonite swarms present which could perhaps be the reason for lesser oyster fossil preservation as there could have been major paleogeography changes resulting in poor oyster preservation conditions during that era. Heading towards the late middle Turonian, sea level is low and dropping and it’s dropping so perhaps that would explain the lower oyster content.
With one last strike of her rock hammer and a quick examination of the loosened debris, the crew commander determined that the chosen location was indeed devoid of oyster fossils and the crew began its way back to the rovers soon after, taking in the landscape and gathering beautiful chert and agate rocks along the way. Albeit the outcome of the EVA was not completely fulfilled, the crew commander explained how intriguing this absence of oysters truly was. On the scale of a large inland sea that spanned approximately 5500 km, having such a stark contrast of oyster fossil extent just within 4 km is definitely quite remarkable. Therefore, with a long rover journey ahead of us, the crew headed back to the Hab, feeling even more contemplative about the planet’s fascinating geologic history.
The crew encountered quite a few aliens while driving to and from the site with a particularly stubborn canine alien blocking our path midway, but the EVA progressed seamlessly, with an estimated radial walking distance of 2km, resulting in yet another resounding success. The team returned to the Habitat with airlock pressurization commencing at 1324 along with Spirit at 36% charge and 240.0 hours and Curiosity at 30% charge and 262.5 hours.
Destination: Hab Ridge
Coordinates (use UTM WGS 84): N4250500, E517900
Participants: Adriana Brown (Commander), Eshaana Aurora (Crew Geologist), Sara Paule (Crew Journalist), Nathan Bitner (Crew Engineer)
Road(s) and routes per MDRS Map: Drive on Cow Dung Road 0110 southward until Zubrin’s Head, then walk further southwest to Barrainca Butte
Mode of travel: Walking and Driving (Spirit and Curiosity)