%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Baratoux, David
%A Bouley, S.
%A Reimold, W. U.
%A Baratoux, Lenka
%T Morphometric analysis and classification of the three-dimensional geometry of shatter cones
%B Shatter cones : nature and genesis
%D 2016
%E Baratoux, David
%E Reimold, W. U.
%L fdi:010068669
%G ENG
%J Meteoritics and Planetary Science
%@ 1086-9379
%M ISI:000383628500003
%N 8 (No spécial)
%P 1460-1476
%R 10.1111/maps.12610
%U https://www.documentation.ird.fr/hor/fdi:010068669
%> https://www.documentation.ird.fr/intranet/publi/2016/12/010068669.pdf
%V 51
%W Horizon (IRD)
%X Shatter cones are curved fractures decorated with divergent striations that are exclusively associated with impact metamorphism. The terminology "cone" was chosen from the observation of complete or near-complete, roundish, axisymmetric objects with a well-defined apex/apical area. It also imprecisely extends to the curved or subplanar fractures decorated with striations commonly observed at impact sites. The geometry of these objects is therefore highly variable but its significance was never addressed due to the lack of appropriate data. Here, we apply two methods to derive shape models of shatter cones. The first one is based on images acquired using a commercial camera and may be applied on large samples in the field. The second one uses an articulated arm equipped with a digital laser scanner and produces high-resolution and precision shape models of hand-sized samples. The analysis of 20 shape models of shatter cones from nine different impact sites indicates that the surface of shatter cones may be described by quadric surfaces and are generally consistent with hyperboloids, whereas occurrence of paraboloid objects cannot be ruled out. The surface characteristics are generally not consistent with the mathematical definition of a cone. The value of these shape models to discriminate between the different hypotheses of formation of shatter is still limited, as it remains to be resolved which type of surface pertains to which hypothesis. This requires theoretical developments, and experimental or numerical simulations of the propagation of tensile fractures associated with shock waves.
%$ 064 ; 020