Binalud Mountains Research Articles

New Middle and Upper Jurassic ammonites from the Binalud Mountains (Mashhad region, NE Iran)

New Middle and Upper Jurassic ammonites from the Binalud Mountains (Mashhad region, NE Iran)

New tectonic configuration in NE Iran: Active strike‐slip faulting between the Kopeh Dagh and Binalud mountains

In this paper, a combined approach of geomorphic analyses, detailed geological mapping on SPOT 5 satellite images and field surveys, complemented by radiometric dating (40Ar/39Ar) allows proposing a new and consistent tectonic configuration for the northeastern Arabia‐Eurasia collision zone. It favors a simple strike‐slip faulting mechanism in NE Iran accommodating the northward motion of central Iran with respect to Eurasia between the Binalud and Kopeh Dagh mountains. Our results demonstrate that ∼2 mm/a (∼25%) of this northward motion has been transferred from the Binalud to the Kopeh Dagh through the Meshkan Transfer Zone since ∼5 Ma. The modern state of stress deduced from fault kinematics analyses shows N30°E trending maximum stress axis and confirms a dominant strike‐slip faulting mechanism. Combining our geological data with other available data, we conclude that kinematics of deformation can be appropriately described by rigid block faulting in NE Iran; instead, the continuous deformation as it has been thought during the last 3 decades.

Stratigraphy, depositional environments and geodynamic significance of the Upper Bajocian–Bathonian Kashafrud Formation, NE Iran

Abstract A strongly subsiding rift basin in NE Iran, the Kashafrud Basin, opened in the Late Bajocian with the accumulation of more than 2000 m of Upper Bajocian–Upper Bathonian siliciclastic sediments. These sediments comprise the Kashafrud Formation, which crops out along a NW–SE stretch of more than 200 km and occupies a width of 50 km, situated between the Koppeh Dagh and the Binalud Mountains. Ten sections of the formation were logged. Sedimentary environments range from non-marine alluvial fans and braided rivers in the lowermost part of the succession to deltas, succeeded by storm-dominated shelf, slope and deep-marine basin. Monotonous mudstones and turbidites prevail in the deep-marine part of the basin. The thickness and facies of the Kashafrud Formation vary strongly between localities, and reflect distance from the rift margins as well as submarine topography, which was shaped by block tectonics. The Kashafrud Basin is interpreted as the eastern extension of the South Caspian Basin, which entered the rifting stage in the late Early Jurassic and the spreading stage in the Late Bajocian.

The Shemshak Group (Lower–Middle Jurassic) of the Binalud Mountains, NE Iran: stratigraphy, depositional environments and geodynamic implications

Abstract The Lower–lower Middle Jurassic non-marine sedimentary succession of the Binalud Mountains of NE Iran is correlated with the Jurassic part of the Shemshak Group of the Alborz Mountains and subdivided into three formations: the Arefi, the Bazehowz and the Aghounj formations. The succession rests, with angular unconformity, on a metamorphic basement deformed during the Late Triassic Eo-Cimmerian orogeny. The lowermost unit, the Arefi Formation, is subdivided into a lower Derekhtoot Member and an upper Kurtian Member. The Derekhtoot Member (up to 750 m thick) consists of very coarse-grained, chaotic boulder beds, breccias and conglomerates representing rock-fall deposits and proximal–middle alluvial fans, deposited along steep fault scarps. The succeeding Kurtian Member (>300 m) comprises finer-grained conglomerates with well-rounded clasts, reflecting deposition in a proximal braided river system. The overlying Bazehowz Formation is more than 1000 m thick and consists of vertically stacked, decametre-scale channel-fill cycles of the middle reaches of a braided fluvial system. The uppermost unit, the Aghounj Formation, consists of at least 400 m of granule- to pebble-size, thick-bedded and large-scale trough cross-bedded quartz conglomerates and sandy interbeds of a proximal braided fluvial system. The overall succession fines upwards due to erosion, down to metamorphic basement, of a high-relief source area in the NE, and rests on Cimmerian basement, suggesting that the strata are intramontane deposits of the Cimmerian mountain chain in NE Iran. This interpretation has important implications concerning the position of the NW–SE-trending Eo-Cimmerian suture in NE Iran, which should be placed further SW than formerly assumed.

NEW OCCURRENCES OF THE TRACE FOSSIL PALEODICTYON IN SHALLOW MARINE ENVIRONMENTS: EXAMPLES FROM THE TRIASSIC-JURASSIC OF IRAN

Abstract The graphoglyptid trace fossil Paleodictyon, characterized by a stratiform hexagonal net, is a diagnostic member of the deep-water Nereites ichnofacies and usually found in deep-sea flysch successions. Scattered records of the trace fossil from shallower, lower-shelf-to-upper-slope environments, particularly since the mid-Mesozoic, have been substantially augmented by new data from Upper Triassic and Jurassic sedimentary basins of Iran. Paleodictyon has been found on the soles of mid-to-lower-shelf event beds produced by storm-induced currents and on the soles of prodelta turbidite deposits in the Upper Triassic Nayband Formation of east-central Iran, the lower Middle Jurassic Shemshak Formation of north-central Iran, the Middle Jurassic Kashafrud Formation of the Koppeh Dagh, and the Middle Jurassic Dalichai Formation of the Binalud Mountains. It appears that the bathymetric range of Paleodictyon throughout the Phanerozoic was considerably wider than generally assumed. The observed dominance of ...

Geological Investigations in the Binalud Mountains (NE-Iran)

Geological Investigations in the Binalud Mountains (NE-Iran)

The Paleozoic Rocks of the South Binalud Mountains, NE Iran, an Exploration Target for Fe, Pb, Zn and Ba

The Paleozoic Rocks of the South Binalud Mountains, NE Iran, an Exploration Target for Fe, Pb, Zn and Ba