A time-table for the levant volcanic province, according to K-Ar dating in the golan heights, Israel

Abstract

The Levant Volcanic extends through northeastern Jordan and Syria to the Golan Heights. Minor volcanic fields also developed in the northern Israel, around the Hula Valley (northern Israel) and in southern Lebanon. This province is a part of an extensive volcanic field which developed during the Cenozoic in the northwestern part of the Arabian plate, aligned roughly in a northwestern direction, subparallel to the Red Sea. The location of the Golan Heights is significant because of its proximity to the Dead Sea Rift Valley, which is assumed to be a transform fault on the Red Sea spreading system.

The volcanic sequence in the Golan Heights and its surroundings, named the “Bashan Group”, overlies the Lower Pliocene regional erosional unconformity. This group is subdivided into five rock units which differ in certain aspects of their morphologic attributes as well as in their radiogenic ages, based on 175 K-Ar age determination made on samples from 54 selected sites:

• 1.

  1. Lower Pliocene basalts (5.0-3.Ma.)

• 2.

  2. Upper Pliocene basalts (2.9-1.7 Ma)

• 3.

  3. Lower Pleistocene basalts (1.6-0.7 Ma).

• 4.

  4. Upper Pleitocene basalts (0.4-0.1 Ma.)

• 5.

  5. Holocene basalts (no data yet).

The Lower Pliocene basalts create a large volcanic plateau from southern Syria to the Lower Galilee. The present Dead Sea Rift in northern Israel began to subside at the end or after this phase, and the Upper Pliocene basalts flowed into it from Lebanon to the Hula Valley. Pleistocene volocanic sources were recognized only in the eastern side of the Rift.

The mean rate of tectonic lowering of the Dead Sea Rift bottom south of the Sea of Galilee is estimated to have been 0.24 mm/yr. The incision rate of the Yarmouk River (the main tributary of the Jordan River) was 0.13 mm/yr, and the rate of the infilling of the Rift in this region was 0.11 mm/yr.