Peakring Character

The outer perimeter of the annular basin, thought to represent the maximum possible diameter of the short-lived transient cavity during the excavation and modification stages (Tsikalas et al. 1998a; Shuvalov et al. 2002), as well as the subfloor compression crater limit (Schultz 1992; Schultz and Gault 1992), exhibits a slightly raised relief (Fig. 1 and 2). Although irregular in shape, and varying in width from 1 to 3 km, the raised relief gives the impression of a

Fig. 5. Morphological characteristics of the decompacted impact-induced intensely disturbed zone (cfr. Fig. 2 and 4; dark-grey raster) derived through mapping of the entire seismic reflection dataset. Light-shading denotes the central bowl-shape part of the disturbance approximately at the limit of the annular basin; dark-shading denotes the transient cavity maximum depth. Contour interval in meters, but not uniform.

Fig. 5. Morphological characteristics of the decompacted impact-induced intensely disturbed zone (cfr. Fig. 2 and 4; dark-grey raster) derived through mapping of the entire seismic reflection dataset. Light-shading denotes the central bowl-shape part of the disturbance approximately at the limit of the annular basin; dark-shading denotes the transient cavity maximum depth. Contour interval in meters, but not uniform.

subdued ring structure, similar to those typically found in peak ring craters, and was thus referred to as a peak ring feature by Tsikalas et al. (1998b).

In the greatest detail, the peak ring at Mjolnir is clearly defined as a raised near-arcuate feature delineated by opposite dipping faults with 10-30 m throws (Fig. 1). This characteristic shape becomes less clear in the N- and

NE-directions where the raised relief is breached and the peak ring remains open, being replaced by faults facing the crater center (Fig. 1).

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