Pinnacle Rock - Ash Tafoni The volcanic ash of Pinnacle Rock is an example of tafoni - salt spray erosion. Tafoni (a rare cavernous weathering process) has scooped out hollows at the pinnacle's base. In addition to caves there are honeycombed cells (stone lace, or stone lattice). The stone lace develops because calcite-laden water flows along cracks. Over time the calcite cements the cracks, but the rest of the stone is weaker and erodes away. In California we see tafoni erosion in sandstone. Bartolome Island.
135 of 297 Index - or click on photo to advance