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The close proximity of the Roman volcanic province to the Tyrrhenian Sea coastline provides a unique opportunity to combine clastic stratigraphy with 40Ar/39Ar geochronology to constrain the timing of Pleistocene sea-level oscillations. The main eruptions from the Monti Sabatini volcanic district occurred during the interval 560-280 ka, and the Alban Hills volcanic district main eruptions span 560-350 ka. The interfingering of volcanics from these two centers with fluvial and shallow-marine sediments of the Tiber River and delta provides a datable relative sea-level record for this portion of middle Pleistocene time. We calculate the timing of glacial terminations using analytical errors only, then assess age uncertainties that include analytical plus systematic errors; the latter is required to compare 40Ar/39Ar ages with those from other dating methods. Terminations III, V, and VI occur at 278 (261,285) ka (95% confidence interval), 430 (422, 442) ka, and 534 (520, 541) ka, respectively, when only analytical uncertainties are used to calculate the ages of bracketing volcanic horizons. The confidence interval expands significantly when full external errors are considered, with predicted ages of 276 (258, 289) ka, 430 (416, 448) ka, and 533 (512, 548) ka for the terminations. The resultant 40Ar/39Ar chronology is generally consistent with the deep-sea [[Delta].sup.18]O record of sea-level change tuned to Earth's obliquity cycle for glacial terminations VI, V, and HI. In addition, the 40Ar/39Ar constrained Tiber River delta sea-level record has the added benefit of identifying when coastal sections respond to complex (multistep) terminations.

Volcanic horizons interbedded with fluviodeltaic clastic sediments of the Tiber and Fosso Galeria River valleys near Rome provide a unique opportunity to date five middle Pleistocene fining-upward aggradational sections. 40Ar/39Ar ages from the interbedded volcanic beds illustrate that aggradation occurred on an approximate 100 k.y. cycle and was initiated by sea-level rise associated with glacial melting. The age constraint additionally shows that aggradation occurs rapidly in response to sea-level change, and thus ages from volcanic strata within the aggradational sections provide high-resolution constraint on the timing of relative sea-level rise. The established chronology is consistent with other glacial proxies and their (radioisotopically or orbitally based) time scales for the timing of glacial terminations VI and V, but is significantly older than most records for the timing of termination III. Ultimately, the age of each termination should be determined by radioisotopic means, and to that end the work here shows that fluviodeltaic sedimentology provides valuable information for middle Pleistocene time-scale calibration.

In and around Rome, coastal and fluvial sediments influenced by Quaternary sea-level changes interfinger with accurately datable, highly potassic pyroclastic volcanic units. We describe the complex internal geology of the Capitoline Hill, for centuries a place of leading importance in ancient Rome and more recently a focus of archaeological research. Outcrops and many new drill cores reveal at least four cycles of valley cutting and filling, probably recording the history of the Tiber River in response to changes in sea level. Single-crystal 40Ar/39Ar dates on sanidine give ages of 518 [+ or -] 6, 413 [+ or -] 5, and 353 [+ or -] 2 ka for three prominent volcanic units filling separate paleovalleys. The Roman region offers the potential for direct age calibration of the Quaternary sea-level record.

Provides a detailed geochronology for some of the major and minor eruptive events which were identified from the Alban Hills and Monti Savatini volcanic centers in Italy. Information on both centers; Occurances of eruptions from the Monti Sabatini volcanic district; Details relating to volcanic stratigraphy.