leg site hole age mnemonic auxiliary age mnemonic top of section depth(m) bottom of section depth(m) special condition age auxiliary age averaged age age top of section(million years) age bottom of section(million years) average age(million years)t data source 6 48 B LOWER PLIOCENE 50.9 53.4 NO AGE GIVEN NO AGE GIVEN 3.4 5 4.2 DSDP INITIAL REPORTS 6 48 B UPPER MIOCENE 53.4 58.4 NO AGE GIVEN NO AGE GIVEN 5 10.5 7.75 DSDP INITIAL REPORTS 6 48 B MAESTRICHTIAN 58.4 71.9 NO AGE GIVEN NO AGE GIVEN 65 70 67.5 DSDP INITIAL REPORTS