Large Meteorite Impacts and Planetary Evolution IV

The complex impact crater Jebel Waqf as Suwwan in Jordan: Effects of target heterogeneity and impact obliquity on central uplift formation
-
Published:September 01, 2010
-
CiteCitation
T. Kenkmann, W.U. Reimold, M. Khirfan, E. Salameh, H. Khoury, K. Konsul, 2010. "The complex impact crater Jebel Waqf as Suwwan in Jordan: Effects of target heterogeneity and impact obliquity on central uplift formation", Large Meteorite Impacts and Planetary Evolution IV, Roger L. Gibson, Wolf Uwe Reimold
Download citation file:
- Share
The recently discovered 6-km-diameter impact structure Jebel Waqf as Suwwan of Jordan (31°02.9′N, 36°48.4′E) has a prominent outer rim and a well-exposed central uplift of ~1000 m diameter, which provides a section through the entire target stratigraphy. The impact occurred into sedimentary rocks of considerable competence contrast. The innermost area of the central uplift exposes Lower Cretaceous sandstones, the oldest strata of the crater. Limestones and marly limestones surround this core and are dismembered into competent blocks that are internally folded. The limestone blocks, in turn, are encircled by a sequence of incompetent marls and chalks. These weak beds accommodated space incompatibilities during block deformation of the competent beds beneath and above. Thick chert beds form the prominent outer collar of the central uplift. Radial folding and faulting are the most conspicuous structural attributes of this sequence. In the southwestern part of the collar, normal layering dominates, and fold axes plunge outward, whereas overturning of strata and fold axes is the rule in the northeastern part. This indicates a top-to-NE shearing component that is explained by an oblique impact scenario with an impact from the southwest. The inferred trajectory runs parallel to the SW-NE axis of symmetry of the central uplift defined by the exposure of strata. Block sizes in limestones and cherts of the central uplift increase with increasing radial distance; however, block sizes are also influenced by the different strength properties of limestone and chert. Shatter cones are abundant throughout the Waqf as Suwwan central uplift, but they also occur prominently along its periphery. Other shock features, such as planar deformation features, planar fractures, and feather features, occur exclusively in Lower Cretaceous sandstones; limestone and microcrystalline chert—the dominant lithologies—are devoid of such effects. The moat between the central uplift and crater rim is largely covered by alluvial wadi sediments. The crater rim is composed of white marls and massive chert beds of Eocene age, the youngest strata of the crater, which also provide a maximum age for the cratering event. Both antithetic and synthetic block slumping are common along the uplifted crater rim.
- Asia
- carbonate rocks
- chemically precipitated rocks
- chert
- clastic rocks
- Cretaceous
- cryptoexplosion features
- deformation
- faults
- folds
- heterogeneity
- heterogeneous materials
- impact craters
- impact features
- impacts
- Jordan
- limestone
- Lower Cretaceous
- mapping
- marl
- mechanical properties
- Mesozoic
- Middle East
- morphology
- oblique orientation
- planar deformation features
- sandstone
- sedimentary rocks
- shatter cones
- strength
- topography
- uplifts
- central uplifts
- target rocks
- complex craters
- Jebel Waqf as Suwwan