What are the enigmatic "coffee bean"-like globules and bullets in the deposits of the delta ?
-- An attempt at an explanation --
Spherical to ellipsoidal objects can be found both in the layered deposits of ash and in larger form as conglomerate. They are often distinguished by a side seam where they have sometimes been split in half. Close-ups show that there are some bright mineral bands and an outer ring arranged equartorially in the interior.
If we assume that the objects
is volcanic ejecta, the question of these puzzling characteristics remains
open. The mineral-separations probably took place in the molten state. The
rounded shape suggests a rotation of the object. But why the ribbons and the
outer ring appear to be arranged equatorially I cannot explain physically.
Larger accumulation of globules in layered ash deposit