Geothermal Investigations in the Dead Sea Rift Zone, Israel: Implications for Petroleum Geology (original) (raw)
Related papers
The thermal structure of Israel and the Dead Sea Fault
Tectonophysics, 2013
In this paper we analyze temperature data from all the available oil and water wells in Israel and compare the results with seismicity depth and with heat flux estimation from xenoliths. We show that the average heat flux in Israel is 40-45 mW/m 2 , consistent with measurements of the Arabian Shield. A heat flux anomaly exists in Northern Israel and Jordan. This could be attributed to groundwater flow or young magmatic activity (~100,000 years) that is common in this area. A higher heat flux exists in Southern Israel and Jordan, probably reflecting the opening of the Red Sea and the Gulf of Eilat (Gulf of Aqaba) and does not represent the average value present in the Arabian Shield. The temperature gradient at the Dead Sea basin is relatively low, resulting in low heat flux (b 40 mW/m 2 ) and a relatively deep seismicity extending to lower crustal depths, in agreement with earthquake depths (b 25-30 km). Higher heat fluxes at the Sea of Galilee (70 mW/m 2 ) and at the Gulf of Eilat (65 mW/m 2 ) results with shallower seismicity (b 10-12 km). The steep geothermal gradients yielded by xenoliths (>80 mW/m 2 ) could be the result of local heating by magmas or by lithospheric necking and shear heating.
Geological Society of …, 1997
The Dead Sea rift valley is a left-lateral transform, along which several rhombshaped grabens were formed. At the Sea of Galilee, which is one of these rhomb-shaped grabens, ambiguous heat fluxes were measured: 70-80 mW/m 2 at the central part of the lake, 36 mW/m 2 at the lake's southern coast (10 km apart), and most surprising, about 135 mW/m 2 at the southern Golan Heights, 6-8 km east of the graben margin. A detailed geologic cross section, traversing the entire sedimentary basin, was constructed. The hydrodynamics in this cross section were analyzed quantitatively using a two-dimensional finite element code that solves the coupled variable-density groundwater flow and conductive-convective heat transfer equations. On the basis of numerical simulations, different mechanisms of basin-scale groundwater convection are suggested for the two sides of the rift that could influence the transport of heat: (1) forced convection (gravitydriven flow) of hot brines from deeper aquifers to the land surface at the western side; and (2) large-scale free convection (buoyancy-driven flow) of deep ground water at the eastern side. The different heat fluxes within the rift valley are attributed to the different lithologies and to the locations of specific conduits through which the hot ground waters ascend from deeper horizons. These simulations also explain the different salinities of the hot springs on the two sides of the rift.
The origin of thermal waters from the eastern flank of the Dead Sea Rift Valley (western Jordan
Terra Nova, 2003
Thermal waters emerging along the eastern flank of the northernmost part of the Dead Sea Rift Valley close to the Yarmuk river are dilute, Ca–SO4–(HCO3) and Na–Cl water types with measured temperatures of 35–60 °C and estimated teperatures, according to silica solubility, of 60–110 °C. They are fed only by present-day recharged meteoric waters (Wadi Hasa, Al Himma and North Shuna thermal baths) and by meteoric waters contaminated with saline waters (El Ma'in thermal Bath). Although they have been known for a long time, there is still dispute about their origins and the source of heat. On the basis of new chemical and isotopic analyses, the saline waters could represent residual pockets of groundwater in equilibrium with those filling the Dead Sea depression before the last retreat of Lake Lisan at 17–15 kyr bp or with the ancient seawaters of the Sedom Lagoon in the early Pleistocene, in both cases unaffected by significant evaporation processes but chemically and isotopically modified by water/rock interaction.
Thermomechanical model reconciles contradictory geophysical observations at the Dead Sea Basin
[1] The Dead Sea Transform (DST) comprises a boundary between the African and Arabian plates. During the last 15–20 m.y. more than 100 km of left lateral transform displacement has been accumulated on the DST and about 10 km thick Dead Sea Basin (DSB) was formed in the central part of the DST. Widespread igneous activity since some 20 Ma ago and especially in the last 5 m.y., thin (60–80 km) lithosphere constrained by seismic data and absence of seismicity below the Moho, seem to be quite natural for this tecton-ically active plate boundary. However, surface heat flow values of less than 50–60 mW/m 2 and deep seismicity in the lower crust (deeper than 20 km) reported for this region are apparently inconsistent with the tectonic settings specific for an active continental plate boundary and with the crustal structure of the DSB. To address these inconsistencies which comprise what we call the " DST heat-flow paradox, " we have developed a numerical model that assumes an erosion of initially thick and cold lithosphere just before or during the active faulting at the DST. The optimal initial conditions for the model are defined using transient thermal analysis. From the results of our numerical experiments we conclude that the entire set of observations for the DSB can be explained within the classical pull-apart model assuming that the litho-sphere has been thermally eroded at about 20 Ma and the uppermost mantle in the region have relatively weak rheology consistent with experimental data for wet olivine or pyroxenite.
Geothermal studies in oilfield districts of Eastern Margin of the Gulf of Suez, Egypt
NRIAG Journal of Astronomy and Geophysics, 2014
Results of geothermal studies carried out at 149 onshore oil wells have been used in evaluation of temperature gradient and heat flow values of the eastern shore of the Gulf of Suez. The investigations included temperature logs in boreholes, calculation of amplitude temperature, geothermal gradients and heat flow. The results obtained indicate that geothermal gradient values are in the ranges of 0.02-0.044°C/m and regionally averaged mean heat flow values are found to fall in the interval of 45-120 mW/m 2 . Temperature gradients and heat flow values change from low values eastward to high values toward the axial of Gulf of Suez rift. The result of this research work has been highly successful in identifying new geothermal resources eastward of the Gulf of Suez. Additionally, this study shows that the areas with relatively higher temperature gradients have lower oil window, mature earlier, than those with low gradient values. Thus, high temperature gradients cause to expedite the formation of oil at relatively shallow depths and narrow oil windows. On the other hand, low temperature gradient makes the oil window to be quite broad when locate at high depths.
Temperature-composition-depth relationship in Rift Valley hot springs: Hammat Gader, northern Israel
Chemical Geology, 1979
Starinsky, A., Katz, A. and Levitte, D., 1979. Temperature--composition--depth relationship in Rift Valley hot springs: Hammat Gader, northern Israel. Chem. Geol., 27: • 233--244. The Hammat Gader (E1-Hamma) springs constitute a rift valley hot-spring system. The five springs which belong to this complex are distinguished by temperatures of 25, 28, O , . .
Tectonophysics, 1987
Feinstein, S., 1987. Constraints on the thermal history of the Dead-Sea Graben as revealed by coal ranks in deep boreholes. In: Z. Ben-Avraham (Editor), Sedimentary Basins within the Dead Sea and Other Rift Zones. Tectonophysics, 141: 135-150. Coal ranks have been studied by vitrinite reflectance measurements in three boreholes; Zuk Tamrut 1 and Zohar 8 on the Judea Desert plateau (adjacent to the 8raben margin} and Amiaz 1 on a don-fasts block at the southwest Dead-Sea Graben. In the ptateau boreholes, me-tem~atu~ index (TIT) calculations reveal that the coalifieation profile probably evolved under a Late Cretaceous thermal event with a thermal gradient of 35"-38*Cfkm followed by gradual decay to the present level, c. 20°C/km by Miocene time. In Amiaz 1, the highest coal rank encountered, 0.5% Ro, is marginal for independent II'1 calculations, however, some constraints on thermal history can be inferred. Stratigraphic and structural relationships between the 0.5% Ro isoreflectance in Amiaz 1 and the plateau boreholes reveals that most of the coalification measured in Amiaz 1 pre dates the formation of the graben, and that an additional 3.4 km of Miocene-Holocene graben fiIl barely affected the coalification. Cessation of coahfication despite increasing burial indicates that the post-Miocene thermal gradient in the Amiaz block could not have exceeded 20 o-23' C/km. This finding is consistent with present day heat flow and other geophysical ~fo~ation. Tectonic models for the evolution of the Dead Sea Graben requiring a high thermal regime are inconsistent with the presented data. This raises questions as to the mechanism involved in the formation of rhomb-shaped grabens in general, on the one hand, and for the hypothesis of the "leaky" nature of the Dead Sea transform north of the Gulf of Elat. on the other. The Dead Sea depression is the most prominent of a sequence of rhomb-shaped grabens developed along the continental portion of the Dead Sea transform (Fig. 1). The evolution of such grabens is generally associated with strike-slip movements
The thermal structure of Israel
Solid Earth …, 2011
Heat flux at the Arabian Shield is a significant component in reconstructing tectonic, seismic, and hydrologic models. In this paper we analyze temperature data from all the available oil and water wells in Israel. We show that the average heat flux in Israel is 40-45 mW m −2. A supporting evidence for the low heat flux is the relatively deep seismicity, extending almost to the mantle in the region. A Heat flux anomaly that exists in Northern Israel and Jordan could be attributed to groundwater flow or young magmatic activity (∼100 000 years) that is common in this area. Xenoliths that yield relatively steep geothermal gradients could be the result of local heating by magmas or by lithospheric necking and shear heating. The higher Heat flux in Southern Israel and Jordan probably reflects the opening of the Red Sea and the Gulf of Eilat and does not reflect the average value of the Arabian Shield.