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Chitinozoan biostratigraphy of the early Caradocian Lockne impact structure, Jämtland, Sweden
Author(s) -
GRAHN YNGVE
Publication year - 1997
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.1945-5100.1997.tb01564.x
Subject(s) - biostratigraphy , outcrop , geology , impact structure , paleontology , impact crater , oil shale , physics , astronomy
— The chitinozoan biostratigraphy in seven outcrops and four drilling cores in connection with the Lockne impact structure has been investigated. The impact event took place in early Caradoc ( i.e., ∼460.4 Ma ago ) and in beds corresponding to the lower part of the Lagenochitina dalbyensis Zone (upper Dalby Limestone). The contact between the impact‐related rocks and the secular postimpact sediments can be traced all over the impact structure, and up to a distance of 50 km away from the presumed crater center. The youngest postimpact sediments in the Lockne impact structure correspond to the lower Örå Shale ( Belonechitina hirsuta Zone).