Stratigraphic, geochronologic, and paleomagnetic constraints on Late Cretaceous volcanism in northern Israel

Abstract

Late Cretaceous volcanism in northern Israel is represented by basaltic pyroclastics and lavas at two adjacent localities at Mount Carmel and the Umm el Fahm area. Four Cenomanian and one Senonian volcanic intercalation occur in the marine succession. These volcanic rocks were dated by the 40 Ar/ 39 Ar and K‐Ar techniques using whole rock, amphibole megacrysts, and plagioclase fractions. Paleomagnetic measurements were performed on the Senonian pyroclastics. Amphibole from the oldest Cenomanian volcanic unit in Mount Carmel (the Kerem Maharal pyroclastics, at the base of the Chalk Complex) yielded an age of 97.1 ± 1.7 Ma. The penultimate Cenomanian volcanic unit in Mount Carmel (basalt at Nahal Raqefet and Muhraqa) yielded a whole-rock age of 96.7 ± 0.5 Ma. The youngest Cenomanian volcanic intercalation in the Umm el Fahm area (basalt at Me-Ammi) yielded a whole-rock age of 95.4 ± 0.5 Ma. Amphiboles from the Senonian Bat Shelomo pyroclastics, the youngest volcanic unit in the area, yielded an age of 82.0 ± 1.3 Ma. Three conclusions may be drawn from our new radiometric ages: (1) The major volcanic events operated synchronously at Mount Carmel and the Umm el Fahm area. (2) The chalk complex of Mount Carmel and the Deir Hanna Formation in the Umm el Fahm area are stratigraphically correlated. (3) The new radiometric results agree with biostratigraphically-derived ages, but provide better time constraints for the lithostratigraphic units. The data help to settle previous correlation controversies: the Albian‐Cenomanian boundary is set below the top of the Yagur Formation, and the Cenomanian‐Turonian boundary, above the base of the Muhraqa Formation.