Evidence for volcanic ash fall in the Maya Lowlands from a reservoir at Tikal, Guatemala

Powder X-ray diffraction and petrographic analyses of reservoir sediments from Tikal, Guatemala have identified significant quantities of decomposed volcanic ash in the form of smectite and euhedral bipyramidal quartz crystals. X-ray fluorescence trace element content analysis was used to eliminate distant Sahara-Sahel and Antilles sources. The Zr/Y and Ni/Cr ratios of reservoir sediment from Tikal are consistent with a source from Central American volcanism (e.g., Guatemalan and Salvadoran). AMS radiocarbon dating of the smectite and crystalline quartz-rich reservoir sediments show that volcanic ash fell during the Preclassic, Classic, and Postclassic Maya cultural periods. It may now be possible to develop an effective chronology of ash fall at Tikal and the greater Peten.

► Tikal provides the first evidence of pre-Hispanic volcanic ash fall in the Maya Lowlands.
► Smectite and euhedral bipyramidal quartz, are present in significant quantities at Tikal.
► Volcanic-derived minerals were deposited from Guatemalan and Salvadoran volcanoes.