Numerous high‐temperature combustion metamorphic foci within brecciated mainly calcareous sedimentary rocks in the Dead Sea area (the so‐called ‘Mottled Zone’ complexes) have been interpreted as resulting from in situ oxidation and ignition of dispersed organic matter in bituminous chalks. Geological, chemical and petrological data for the Nabi Musa dome, one of 15 Mottled Zone complexes data presented in this paper, suggest an alternative interpretation relating the Mottled Zone complexes to Pliocene–Pleistocene mud volcanism and the associated methane combustion. The geochemistry and mineralogy of sedimentary, combustion metamorphic, localized hydrothermally, altered rocks, and ignition foci marked by ultrahigh temperature (up to 1500 °C) pseudowollastonite–rankinite–nagelschmidtite‐bearing paralava, indicate that Nabi Musa is a fossil mud volcano, comprising a large diatreme edifice with brecciated sedimentary rocks in its main feeder. The mud volcanic event mobilized sediments of underlying Cretaceous strata from depths of at least 0.8 km, and the eruption was driven by hydrocarbon gases (predominantly methane), with gas flaming causing local combustion metamorphism. Besides ultrahigh temperature combustion metamorphic processes, ejected sedimentary rocks were subsequently altered by low‐temperature hydrothermal fluids from various sources, which produced specific rock compositions with local enrichments in Mg, Na, Cl and B. Later, carbonation almost completely replaced the original smectite‐bearing parent mud and preserved the edifice from erosion. The proposed mud‐volcanic origin of the Mottled Zone complexes may have implications for gas prospecting in the Levantine basin.
The Junggar basin contains an almost continuous section of Late Carboniferous–Quaternary terrigenous sedimentary rocks. The maximum thicknesses of the stratigraphic units constituting the basin cover make up a total of ~23 km, and the basement under the deepest part of the basin is localized at a depth of ~18 km. Both the folded framing and the basin edges have undergone uplifting and erosion during recent activity. These processes have exposed all the structural stages of the basin cover. Considering the completeness and detailed stratigraphic division of the section, we can determine the exact geologic age of intense mountain growth and erosion periods as well as estimate the age of orogenic periods by interpolating the stratigraphic ages. During the Permian orogeny, which included two stages (255–265 and 275–290 Ma), the Junggar, Zaisan, and Turpan–Hami basins made up a whole. During the Triassic orogeny (210–230 Ma), the Junggar and Turpan–Hami basins became completely isolated from each other. During the Jurassic orogeny (135–145 and 160–200 Ma), the sedimentation took place within similar boundaries but over a smaller area. During the Cretaceous orogeny (65–85 and 125–135 Ma), the mountain structures formed mainly at the southern boundaries of the basin and along the Karamaili–Saur line. The Junggar and Zaisan basins were separated at that time. The Early and Middle Paleogene were characterized by relative tectonic quiescence. The fifth orogenic stage began in the Oligocene. The recent activity consists of two main stages: Oligocene (23–33 Ma) and Neogene–Quaternary (1.2–7.6 Ma to the present).
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