ELSEVIER Journal of Volcanology and Geothermal Research 60 (1994) 59-85 Joupmlgf. voka.nology , altogeomermm research Glass chemistry in volcaniclastic sediments of ODP Leg 107, Site 650, sedimentary sequence: provenance and chronological implications Natale Calanchi, Giorgio Gasparotto, Claudia Romagnoli Dipartimento di Scienze Mineralogiche, Universit?, di Bologna, Piazza di Porta S. Donato 1, 40126 Bologna, Italy (Received February 4, 1993; revised version accepted October 19, 1993 ) Abstract A detailed chemical investigation of volcanic glass fragments from volcaniclastic strata (6 tephras, 1 volcanic debris flow, 12 volcanic turbidites) of ODP Leg 107, Site 650, sedimentary sequence, leads to a varied pattern in terms of both provenance and age constraints. The six analyzed tephra strata indicate a provenance from at least three different volcanic provinces: Aeolian, Campanian, and Sicilian Channel (PanteUeria Island). The older tephra strata (021, 018, 012 ) have a large amount of"orogenic" rhyodacite/rhyolitedeposits that may be attributed to the Aeolian province, although no subaerial coeval volcanic activity of similar composition has so far been documented in the Aeolian Arc. Tephra 007 is related to the Pantelleria Island activity and, particularly, to an ignimbrite episode dated circa 130 ka. Tephra strata 005 and 003, have a clear Campanian provenance, and are correlated with analogous tephra layers, observed in the Tyrrhenian and Ionian seas, dated circa 107 and 60 ka respectively. In the oldest portion of the sequence (from 1.3 to 0.13 Ma), the volcaniclastic sediments were only derived from the Aeolian domain whereas in the latest 130 ka, the Campanian influx becomes much more predominant. There- fore, a general K-enrichment trend is observed in the temporal sequence of all the analyzed samples (almost 700 point analyses)which may be related both to a variation in the source area and to the specific Pleistocene magmatic evolution of the peri-Tyrrhenian volcanic provinces. 1. Introduction Volcanic explosive activity from peri-Tyr- rhenian magmatic provinces has been recorded by several tephra layers in the central Mediter- ranean sediments (Keller et al., 1978; Thunnell et al., 1979; Paterne et al., 1988, 1990). It made possible the reconstruction of the temporal evo- lution of the explosive activity of the main vol- canic provinces in the Late Pleistocene (last 80,000 years; last 190,000 years for the Campan- ian Province, Paterne et al., 1988, 1990). Evi- dences of peri-Tyrrhenian volcanic activity in the Early-Middle Pleistocene marine sediments are meager since the Ocean Drilling Program Leg 107 was carried out in the Tyrrhenian Sea. Late Pli- ocene and Pleistocene successions in both the ig- neous-floored Marsili and Vavilov Basins are largely composed of volcaniclastic debris, de- rived from the southern Apenninic Roman and Campanian provinces, and from the Aeolian Is- lands (Shipboard Scientific Party, 1987; Robert- son et al., 1990). The aim of the present paper is to provide, on 0377-0273/94/$07.00 © 1994 Elsevier Science B.V. All fights reserved SSD10377-0273 (93)E0111-E