Composition
The Lohan Cura Formation contains two members of roughly equal thickness.
The lower (and therefore older) of the two is the Puesto Quiroga Member, approximately 85 meters thick. The lowest sediments in this formation are conglomerates, overlain by sandstones and siltstones. The upper two-thirds of the member consists mainly of shales.
The Cullín Grande Member is the upper member within the formation, about 92 meters thick, which contains numerous stream channels in sandstone. By the top of the column, siltstones and claystones become dominant.
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