Present Heat Flow and Paleo-Geothermal Anomalies in the Southern Golan Heights, Israel

While present heat flow (HF) throughout Israel and the Dead Sea Transform (DST) area is considered low, a thermal anomaly exists near the Yarmuk valley at the southern tip of the Golan Heights. New temperature measurements in the southern Golan Heights show that the distribution of the thermal anomaly is significantly wider than previously thought. The new data conforms to either a local and shallow magmatic chamber, which is in thermal steady state with the surrounding rocks, or to a transient heat front associated with localized Pleistocene magmatic intrusions in the Yarmuk. An alternative mechanism suggests that the present HF intensity is higher than the HF value calculated based on the apparent borehole temperatures due to heat removal by deep aquifer flow. A paleothermal analysis was performed using high-resolution organic matter maturation profiles on the Late Cretaceous source rocks, across the southern Golan basin. The maturation data show remarkably similar values throughout the basin, indicating that a single thermal event led to the source rock maturation. Constraints given by geological considerations have associated the paleothermal event with Pliocene volcanic eruptions, which has allowed the calculation of the basin paleo-heat flows, and indicated on a basin wide heat source, such as a crustal heat source. The paleothermal event is sharply bounded by a DST branching fault. This observation is suggested to be related to either strike-slip movement associated with the DST or to heat removal and modulation by a deep hydrological system.