TY - JOUR
T1 - A Late Paleocene age for Greenland's Hiawatha impact structure
AU - Kenny, Gavin G.
AU - Hyde, William R.
AU - Storey, Michael
AU - Garde, Adam A.
AU - Whitehouse, Martin J.
AU - Beck, Pierre
AU - Johansson, Leif
AU - Søndergaard, Anne Sofie
AU - Bjørk, Anders A.
AU - MacGregor, Joseph A.
AU - Khan, Shfaqat A.
AU - Mouginot, Jérémie
AU - Johnson, Brandon C.
AU - Silber, Elizabeth A.
AU - Wielandt, Daniel K.P.
AU - Kjær, Kurt H.
AU - Larsen, Nicolaj K.
PY - 2022/3
Y1 - 2022/3
N2 - The ~31-km-wide Hiawatha structure, located beneath Hiawatha Glacier in northwestern Greenland, has been proposed as an impact structure that may have formed after the Pleistocene inception of the Greenland Ice Sheet. To date the structure, we conducted 40Ar/39Ar analyses on glaciofluvial sand and U-Pb analyses on zircon separated from glaciofluvial pebbles of impact melt rock, all sampled immediately downstream of Hiawatha Glacier. Unshocked zircon in the impact melt rocks dates to ~1915 million years (Ma), consistent with felsic intrusions found in local bedrock. The 40Ar/39Ar data indicate Late Paleocene resetting and shocked zircon dates to 57.99 ± 0.54 Ma, which we interpret as the impact age. Consequently, the Hiawatha impact structure far predates Pleistocene glaciation and is unrelated to either the Paleocene-Eocene Thermal Maximum or flood basalt volcanism in east Greenland. However, it was contemporaneous with the Paleocene Carbon Isotope Maximum, although the impact's exact paleoenvironmental and climatic significance awaits further investigation.
AB - The ~31-km-wide Hiawatha structure, located beneath Hiawatha Glacier in northwestern Greenland, has been proposed as an impact structure that may have formed after the Pleistocene inception of the Greenland Ice Sheet. To date the structure, we conducted 40Ar/39Ar analyses on glaciofluvial sand and U-Pb analyses on zircon separated from glaciofluvial pebbles of impact melt rock, all sampled immediately downstream of Hiawatha Glacier. Unshocked zircon in the impact melt rocks dates to ~1915 million years (Ma), consistent with felsic intrusions found in local bedrock. The 40Ar/39Ar data indicate Late Paleocene resetting and shocked zircon dates to 57.99 ± 0.54 Ma, which we interpret as the impact age. Consequently, the Hiawatha impact structure far predates Pleistocene glaciation and is unrelated to either the Paleocene-Eocene Thermal Maximum or flood basalt volcanism in east Greenland. However, it was contemporaneous with the Paleocene Carbon Isotope Maximum, although the impact's exact paleoenvironmental and climatic significance awaits further investigation.
UR - https://www.scopus.com/pages/publications/85126080454
U2 - 10.1126/sciadv.abm2434
DO - 10.1126/sciadv.abm2434
M3 - Article
C2 - 35263140
AN - SCOPUS:85126080454
SN - 2375-2548
VL - 8
JO - Science Advances
JF - Science Advances
IS - 10
M1 - eabm2434
ER -