Investigation of Deep-Sea Volcanic Ash Layers from Equatorial Pacific Cores

Ash Layers from Deep Sea Drilling Project Leg 84: Middle America Trench Transect

“…Thus in the north equatorial zone, the eastern Pacific mainly receives ashes from Guatemala, El Salvador, Costarica, and possibly southern Mexico. The eolian Central American origin of equatorial Pacific recent submarine ashes was geochemically verified by Boyles et al (1973). The silty size of shards and the presence of micropumice can correspond to eolian transportation exceeding distances of 100 km (Carey and Sigurdsson, 1980).…”

Petrography and Geochemistry of Volcanic Glass: Leg 57, Deep Sea Drilling Project

“…Although deep sea tephra is several hundred or more km from the source volcanic rocks, it is correctable using diagnostic features of volcanic ash. Bowles et al (1973) succeeded in correlating ash layers with the reflected horizons of a 3.5-kHz echogram off the coasts of Guatemala and Costa Rica. Leg 57 sites are located at about 200 to 300 km east of the Quaternary volcanic front on land, and frequent occurrence of many ash layers and ashy pods or pockets in Leg 57 sites produces fruitful correlations.…”

Minerals of the Clay Fraction in Pliocene-Quaternary Sediments of the East Equatorial Pacific

“…Furthermore, acid ash layers from terrestrial volcanoes usually occur with definite periodicity. In deep sea Pliocene-Quaternary sediments of the equatorial Pacific, Bowles et al (1973) singled out the two most extensive ashfall maxima (by volume 43 km 3 and 19 km 3 ); they are dated isotopically to be 220,000 and 54,000 y. old, respectively. These authors consider the Guatemala Upland (Salvador, Columbia, Ecuador, or Nicaragua) to be the most probable source areas of this ash supply.…”