West of Llao 18. Aerial view to west-southwest of Llao Rock from Steel Bay (Panorama E). Note the thick, light-colored wedge of bedded, near-vent pumice-fall deposit (unit rhp) under the right extent of the Llao Rock lava flow (unit rh). Pumice-fall deposit decreases in thickness to east and also is present lining the explosion crater under the Llao Rock lava flow, where it has been compacted and fused to form dark, dense vitric tuff for several meters thickness against the overlying lava. Two dikes can be traced upward into dacite of Steel Bay lava (unit dsb; 116±5 ka); the more obvious dike stands out from the caldera wall, casting a shadow in the lower right corner of the photo. Photograph by Charles R. Bacon. |