HR: 0800h
AN: T51C-0693    [Abstracts]
TI: Magmatics within the Dead Sea transform valley (insights from magnetic data)
AU: * Rybakov, M
EM: rybakov@gii.co.il
AF: GII, Baal-Shem Tov st. 6, Lod, 71100, Israel
AB: The DST – largest continental fissure- appears to be the single shear zone consisting of several en echelon right- stepping faults, with the total sinistral displacement of about 105 km. Gravity data show obviously what the DST locates along the interface between western block with high density oceanic (transition) crust and eastern relatively light density continental crust. Assuming the interface as weakness zone the question is: Can the weakness zone to serve as magma chamber during last ten million years? To delineate and study the magmatic bodies the magnetic survey provides excellent opportunity. The water and sedimentary strata are ‘transparent' and the magnetic anomalies are caused meanly by local magmatic features. Generally the regional magnetic maps are maps of basic magmatics – outcropped and concealed. New high-resolution aeromagnetic surveys covered the southern Arava valley and the western Dead Sea area provided the valuable data to better understanding of the tectonic pattern and distribution of magmatics within the transform valley. The main findings: - presence of the rift-parallel magnetic lineaments corresponding to the active trace of the DST; - lineament system extends NNE as an almost continuous trace over the study areas and shows the same general azimuth of the magnetic lineament and of the segmented fault system as derived from the gravity, geology and topography; - the absence of any magnetic anomalies crossing the Arava Valley; all the local magnetic anomalies in the eastern and western parts of the valley appear to be completely separated; only a lineament appears to separate the local magnetic anomalies; - strong magnetic anomalies suggest hitherto unknown subsurface magmatics. Quantitative interpretation of the high accuracy detailed magnetic measurements allowed to localize the magmatic bodies and to estimate reliable theirs depth. Comparing the results with seismic reflection and geological data the belonging of magmatics located within the transform valley to corresponding magmatic event can be defined as follow: - Wide range of the prerift magmatic events (Precambrian and Phanerozoic intrusives); - Magmatic events synchronic but doesn't associated with the DST (e.g. young basalt flows); - Unrecognized magmatic bodies synchronic to the DST and associated probably with tectonic development of the DST during movement along the main shear system. Such magmatics may mark the main deep penetrated faults. Last case will be thoroughly studied in future. Magmatics are integral part of the Dead Sea transform structure and this knowledge has to be used in exploration of groundwater, oil, earthquake hazard assessment and infrastructure projects, such as the Dead Sea-Red Sea Canal This study was supported by the Earth Sciences Administration of the Ministry of National Infrastructures of Israel and the DESIRE project of the GeoForschungZentrum (Potsdam) and Kiel university.
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: 2007 Fall Meeting