(1) Monotonous purple beds near the base of the Petrified Forest Member
The lower Petrified Forest Member of the Chinle Formation is characterized by a purplish mudstone-rich interval called the "monotonous purple beds" (1). These beds were recovered during the daylight hours and then during the night shift (2) we entered the Martha's Butte beds of the Sonsela Member (3).
The underlying Jim Camp Wash beds of the Sonsela Member contain the Adamanian - Revueltian boundary, a biostratigraphic turnover interval that is minimally broadly coincident with the age of the Manicouagan impact structure in Quebec.
That interval is a major focus of this coring effort.
(2) Kristina Brady of LacCore in the night shift. From:
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(3) Close up of sandstone of th eupper Martha Butte bed of the Sonsela Member. From:
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