The Pleistocene Al Wahbah dry maar crater

Al Wahbah is one of the largest and deepest Quaternary maar craters on Earth that is also accessible through sealed roads and dedicated visitor facilities. It has perfect exposures of the pre-maar and the maar-forming volcanic successions in its crater wall. It is today a ~2.3 kilometer wide, ~250 meter deep NW-SE-elongated crater surrounded by a scalloped near-perpendicular crater wall that cuts into the Neoproterozoic diorite basement and two Quaternary basanite lava flows. Al Wahbah formed by the explosive interaction of magma and water about 1.15 Ma that deposited pyroclasts from pyroclastic density currents, ballistic curtains and pyroclastic falls. The uniqueness of the exposed crater wall sequence is that deposits resulting from the phreatomagmatic explosions engulfed two pre-maar scoria cones and underlying multiple lava flow units. Al Wahbah uniquely demonstrates that subsequent highly explosive eruptions can take place on a field that showed very different eruption styles thousands of years prior the violent explosive blasts that cut a hole-in-the ground within earlier volcanic landforms. The original tephra ring of the maar acted as an obstacle against younger lava flows nearby vents that were diverted along the margin of the tephra ring creating unique pahoehoe lava surface textures marking the original position of the tuff ring.