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Geochemistry of drill core samples from Yaxcopoil‐1, Chicxulub impact crater, Mexico
Author(s) -
Schmitt Ralf T.,
Wittmann Axel,
Stöffler Dieter
Publication year - 2004
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2004.tb00940.x
Subject(s) - impact crater , geology , breccia , dike , geochemistry , impact structure , basement , petrology , astrobiology , physics , civil engineering , engineering
— The chemical composition of suevites, displaced Cretaceous target rocks, and impact‐generated dikes within these rocks from the Yaxcopoil‐1 (Yax‐1) drill core, Chicxulub impact crater, Mexico, is reported and compared with the data from the Yucatán 6 (Y6) samples. Within the six suevite subunits of Yax‐1, four units with different chemical compositions can be distinguished: a) upper/lower sorted and upper suevite (depth of 795–846 m); b) middle suevite (depth of 846–861 m); c) brecciated impact melt rock (depth of 861–885 m); and d) lower suevite (depth of 885–895 m). The suevite sequence (a), (b), and (d) display an increase of the CaO content and a decrease of the silicate basement component from top to bottom. In contrast, the suevite of Y6 shows an inverse trend. The different distances of the Yax‐1 and Y6 drilling sites from the crater center (∼60, and ∼47 km, respectively) lead to different suevite sequences. Within the Cretaceous rocks of Yax‐1, a suevitic dike (depth of ∼916 m) does not display chemical differences when compared with the suevite, while an impact melt rock dike (depth of ∼1348 m) is significantly enriched in immobile elements. A clastic breccia dike (depth of ∼1316 m) is dominated by material derived locally from the host rock, while the silicate‐rich component is similar to that found in the suevite. Significant enrichments of the K 2 O content were observed in the Yax‐1 suevite and the impact‐generated dikes. All impactites of Yax‐1 and Y6 are mixtures of a crystalline basement and a carbonate component from the sedimentary cover. An anhydrite component in the impactites is missing (Yax‐1) or negligible (Y6).