Meteorite impact craters and possibly impact‐related structures in Estonia

Abstract

Abstract-Three structures (Neugrund, Ka¨rdla, and Kaali) of proven impact origin make Estonia the most cratered country in the world by area. In addition, several candidate impact structures exist, waiting for future studies to determine their origin. This article is an overview of these proven and possible impact structures, including some breccia layers. It summarizes the information and descriptions of the morphology; geological characteristics; and mineralogical, chemical, and geophysical data available in the literature. The overview was prepared to make information in many earlier publications in local journals (many of which had been published in Estonian or Russian) accessible to the international community. This review summarizes the facts and observations in a historical fashion, summarizing the current state of knowledge with some additional comments, and providing the references.

Julius Kaljuvee, Ivan Reinwald, and Estonian pioneering ideas on meteorite impacts and cosmic neocatastrophism in the early 20th century

“…After occupation of Estonia by the Soviet army in 1940, another Soviet authority (thanks to the study of Tunguska impact), Leonid A. Kulik (1883Kulik ( -1942born in Tartu), promoted the realization of this huge project, paired with research works on Kaali craters (see Aaloe, 1963 andPlado, 2012, for review of the real progress). He placed the project in a distinctive geopolitical viewpoint: "What was not in the power of a tiny capitalist Estonian state is by any means feasible in the huge Soviet Union" (Kulik, 1940, p. 65).…”

“…In Estonia independent again, the subsequent studies on the Kaali crater field focused on its refined dating, sub-surface crater morphology and associated meteoritic matter (e.g., Raukas et al, 2005;Stankowski, 2010, 2011;Plado, 2012;Zanetti et al, 2015), but also on ecological and social effects of the impact (Veski et al, 2007). In particular, the age of impact was precised as recent as 3237 ± 10 years ago, in light of 14 C dating charcoal within proximal ejecta (Losiak et al, 2016).…”

“…2) and related group of small craters on the Baltic island of Oesel (= Saaremaa; cf. Kaali Meteorite Crater Field), as early as in 1922 (or even in 1919 -see Reinwald, 1928;Spencer, 1938;Aaloe, 1963;Raukas and Stankowski, 2011;Plado, 2012). Furthermore, Kaljuvee has been recently presented as a forerunner of impact explanation of the famous Ries structure in Bavaria by Martina Kölbl-Ebert (2015).…”

A ground-penetrating radar study of the Vaidasoo bog (Estonia): no crater structure exists

“…Pres ently, three struc tures (Kaali, Kärdla and Neugrund) of con firmed im pact or i gin are known in Es to nia (Plado, 2012). How ever, there are sev eral other cir cu lar struc tures the or i gin of which has been un clear.…”

Impact craters and the extraterrestrial matter in their surroundings: case of Morasko (Poland) and Kaali (Estonia)

“…Meteorite fall has been and is a natural process happening throughout the existence of the Earth. In the Central and Eastern Europe there have been at least several of such events in the last ten thousand years (Stankowski 2001a(Stankowski , 2008Raukas et al 2001;Baillie 2007;Stankowski et al 2007;Plado 2012). Such falls can create simple or multiple craters with different abilities to occur in morphology (Suuroja K., Suuroja S. 2010;Plado 2012).…”