Fig. 3
From: Geochemical approaches to the quantification of dispersed volcanic ash in marine sediment
Closeup photos and photomicrographs of ash layers from ODP Site 998, western Caribbean Sea. (Left) Volcanic ash layer in Section 165-998A-10H-4, 50–72 cm. Note the sharp base and transitional top that has been reworked by bioturbation. (Right, top) Section 165-998A-19X-3, 55–56 cm. Typical rhyolitic glass shards from a 13.8 Ma volcanic ash fall layer. The width of the field of view is 0.5 mm. (Right, bottom) Typical fresh (clear) and altered (cloudy) glass shards and an amphibole phenocryst in a 15 Ma volcanic ash fall layer in Section 165-998A-21X-3, 51–52 cm. From Sigurdsson, Leckie, Acton, et al. 1997