| Full text | |
| Author(s): |
Kenkmann, Thomas
[1]
;
Vasconcelos, Marcos A. R.
[2, 3]
;
Crosta, Alvaro P.
[2]
;
Reimold, Wolf U.
[3]
Total Authors: 4
|
| Affiliation: | [1] Univ Freiburg, Inst Geowissensch Geol, D-79104 Freiburg - Germany
[2] Univ Estadual Campinas, Inst Geosci, BR-13083970 Sao Paulo - Brazil
[3] Humboldt Univ, Leibniz Inst, Museum Nat Kunde, D-10115 Berlin - Germany
Total Affiliations: 3
|
| Document type: | Journal article |
| Source: | METEORITICS & PLANETARY SCIENCE; v. 46, n. 6, p. 875-889, JUN 2011. |
| Web of Science Citations: | 19 |
| Abstract | |
Serra da Cangalha is a complex impact structure with a crater diameter of 13,700 m and a central uplift diameter of 5800 m. New findings of shatter cones, planar fractures, feather features, and possible planar deformation features are presented. Several ring-like features that are visible on remote sensing imagery are caused by selective erosion of tilted strata. The target at Serra da Cangalha is composed of Devonian to Permian sedimentary rocks, mainly sandstones that are interlayered with siltstone and claystones. NNE-SSW and WNW-ESE-striking joint sets were present prior to the impact and also overprinted the structure after its formation. As preferred zones of weakness, these joint sets partly controlled the shape of the outer perimeter of the structure and, in particular, affected the deformation within the central uplift. Joints in radial orientation to the impact center did not undergo a change in orientation during tilting of strata when the central uplift was formed. These planes were used as major displacement zones. The asymmetry of the central uplift, with preferred overturning of strata in the northern to western sector, may suggest a moderately oblique impact from a southerly direction. Buckle folding of tilted strata, as well as strata overturning, indicates that the central uplift became gravitationally unstable at the end of crater formation. (AU) | |