Magnetostratigraphy of sediments recovered at sites 650, 651, 652, and 654 (Leg 107, Tyrrhenian Sea)

Abstract

Four implications of the proposed correlations are: 1) The Mio-Pliocene boundary occurs in the lowest reversed interval of the Gilbert (Chron 3r) at about 4.9 Ma 2) The thick pre-Pliocene lacustrine sequence recovered at Site 652 appears to have been deposited entirely within a single reversed polarity chron (Chron 3r). 3) The balatino-type gypsum recovered at Site 654 was also deposited entirely within this polarity chron (Chron 3r), 4) The Tortonian-Messinian boundary occurs within a normal polarity zone which is probably correlative to Chron 6 (Chron 3B) giving a boundary age of about 6.4 Ma. -from Authors