Premium
The Stratigraphy, Sedimentology, and Fossils of the Haughton Formation: A Post‐Impact Crater‐Fill, Devon Island, N.W.T., Canada
Author(s) -
Hickey Leo J.,
Johnson Kirk R.,
Dawson Mary R.
Publication year - 1988
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1988.tb01284.x
Subject(s) - geology , impact crater , breccia , paleontology , impact structure , lithology , macrofossil , siltstone , conglomerate , cretaceous , sedimentology , cobble , stratigraphy , debris , geochemistry , geomorphology , sedimentary rock , facies , tectonics , oceanography , physics , astronomy , structural basin , holocene , ecology , habitat , biology
— After the impact that formed Haughton crater, 22.4 ± 1.4 Ma ago (early Miocene), the cavity filled with water and began to accumulate lacustrine sediments. These preserve detailed evidence of pre‐impact stratigraphy and post‐impact morphology and development of the crater, as well as of the climatic and biotic regime in which it lay. In this report we formally designate these sediments as the Haughton Formation, of which only a 48 m thick remnant covering approximately 7 km 2 still exists. Dolomite‐rich, poorly‐sorted silt, fine sand, and mud are the principal lithologies. The formation unconformably overlies a blanket of allochthonous impact breccia forming the floor of the original crater. Presence of a debris‐flow deposit in the base of the sequence indicates that lacustine deposition began very shortly after crater formation. The Haughton Formation contains a moderately diverse and highly endemic vertebrate fauna as well as palynomorphs and plant macrofossils that indicate a cool‐temperate climatic regime. A small percentage of reworked Late Cretaceous and early Tertiary palynomorphs point to the former existence of the Eureka Sound Formation in the drainage area of the crater. In addition, the distribution of the lake beds indicates the absence of an inner ring on the west side of the crater, and the 3° to 3.5° inward dip of Haughton strata implies that the central mass has subsided approximately 300 to 350 m since deposition began.