Vakkejokk Breccia - Impact Deposit

Alternate Names N/A
Coordinates 68° 22' 12" N; 19° 15' 36" E
Notes
  1. Coordinates based on study area (fig 6) in Ormö et al., 2017
Country Sweden

Related Countries :
  1. Sweden
Region North of Lake Torneträsk in Lapland, Sweden
Date Confirmed 2011
Notes
  1. Has been known as an anomaly in this region since the 1960s, but was only proposed as having an impact origin since 2011 (Alwmark et al., 2018; Nielsen and Schovsbo, 2011)
Age (Ma) ~520
Notes :
  1. As part of the Torneträsk formation, the Vakkejokk Breccia sits on the Lower Sandstone and Lower Siltstone members and underneath the Red and Green Siltstone member. Age was determined based on this positioning (Ormö et al., 2016, Nielsen and Schovsbo, 2011)

Method :
  1. Stratigraphic dating
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
Orddajohka
Spherules
Unknown
Tektites
Unknown
Indivudual Glass Clasts
Unknown
Source Crater
Unknown
Geology
Deposited in a shallow, marine environment. The breccia is made of a disturbed lower polymict sub unit with crystalline mega-clasts surrounded by contorted sediments; the middle consists of a normally graded, crystalline-rich, polymict subunit; and the upper subunit is a thin, fine-grained quartz sandstone
  1. Ormö et al., 2016
Other Shock Metamorphism
Unknown
Shatter Cones
No
Planar Fractures
Yes
  1. Evidence of PFs in one sample of the graded polymict breccia (Alwmark et al., 2018)
Planar Deformation Features
Yes
  1. In 2016, PDFs were the only form of shock metamorphism found. PDFs were found in the upper parts of the graded polymict breccia and in the top sandstone (Ormö et al., 2016). This was verified in 2018 and PFs were additionally found (Alwmark et al., 2018).
Diaplectic Glass
No
  1. Ormö et al., 2016
Coesite
No
Stisovite
No

References

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A T Nielsen, N H Schovsbo (2011) The Lower Cambrian of Scandinavia: Depositional environment, sequence stratigraphy and palaeogeography, Earth-Science Reviews 107(3-4), p. 207-310, url, doi:10.1016/j.earscirev.2010.12.004

J Ormö, A T Nielsen, C Alwmark (2016) The Vakkejokk Breccia, Northernmost Sweden: A Cambrian Analogue to the Proximal Ejecta Layer and Resurge Deposits at the Ordovician Lockne Marine-Target Crater, 79th Annual Meeting of the Meteoritical Society 79, p. 6022, url

J Ormö, A T Nielsen, C Alwmark (2017) The Vakkejokk Breccia: An Early Cambrian proximal impact ejecta layer in the North-Swedish Caledonides, Meteoritics and Planetary Science 52(4), p. 623-645, University of Arkansas, url, doi:10.1111/maps.12816

C Alwmark, J Ormö, A T Nielsen (2019) Shocked quartz grains in the early Cambrian Vakkejokk Breccia, Sweden—Evidence of a marine impact, Meteoritics and Planetary Science 54(3), p. 609-620, University of Arkansas, url, doi:10.1111/maps.13230