Abstract
The article comprehensively presents little known Estonian contribution to the recognition of first meteorite impact structures in Europe, related to works of Julius Kaljuvee (Kalkun; 1869–1940) and Ivan Reinwald (Reinwaldt; 1878–1941). As an active educator specialized in geoscience, Kaljuvee was the first to hypothesize in 1922 that Kaali lake cirque in Saaremaa Island, Estonia, was created by meteorite impact. Thanks to mining engineer Reinwald, this assumption was accepted since 1928 due to the exhaustive field and borehole works of the latter (also as a result of exploration by several German scholars, including renowned Alfred Wegener). The impact origin of Kaali structure was proved finally in 1937 by finding of meteoritic iron splinters (as the first European site). Reinwald was not only outstanding investigator of meteorite cratering process, but also successful propagator of the Estonian discoveries in Anglophone mainstream science in 1930s. In addition, in his 1933 book, Kaljuvee first highlighted an impact explanation of enigmatic Ries structure in Bavaria, as well as probable magmatic activation in distant regions due to “the impulse of a giant meteorite”. He also outlined ideas of the inevitable periodic cosmic collisions in geological past (“rare event” theory nowadays), and resulting biotic crises. In a general conceptual context, the ideas of Kaljuvee were in noteworthy direct or indirect link with concepts of the great French naturalists – Laplace, Cuvier and Élie de Beaumont. However, some other Kaljuvee’s notions, albeit recurrent also later in geoscientific literature, are queer at the present time (e.g., the large-body impact as a driving force of continental drift and change the Earth axis, resulting in the Pleistocene glaciation). Thus, the Kaljuvee thought-provocative but premature dissertation is rather a record of distinguishing erudite activity, but not a real neocatastrophic landmark in geosciences history. Nevertheless, several concepts of Kaljuvee were revived as the key elements in the current geological paradigm.
Highlights
Meteor Crater in central Arizona (Colorado Plateau, USA), the first historically recognized meteorite impact structure, is presently understood as an undoubted, ideally preserved signature of cosmic collision on the surface of the Earth that significantly influenced our understanding of geological history, and its links with the whole solar system (Marvin, 1986; Hoyt, 1987; French, 1998; Kölbl-Ebert, 2015; Powell, 2015)
Summarizing all the pioneer attempts to ascertain the origin of the mysterious Estonian crateriform structure, varieties of endogenic explosion and sinkhole models persisted well in the time of early Julius Kaljuvee scientific activity
A somewhat similar cognitive stage in discussions on explosive cratering processes had existed in the case of Meteor Crater since Gilbert (1896; Keyes, 1907), at least in judgment of large part of the geoscientific community
Summary
Meteor (or Barringer) Crater in central Arizona (Colorado Plateau, USA), the first historically recognized meteorite impact structure, is presently understood as an undoubted, ideally preserved signature of cosmic collision on the surface of the Earth that significantly influenced our understanding of geological history, and its links with the whole solar system (Marvin, 1986; Hoyt, 1987; French, 1998; Kölbl-Ebert, 2015; Powell, 2015). Kaljuvee (earlier Kalkun) was noted in several papers as the first proponent of meteoritic origin for a Kaali lake (Fig. 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). Aims of the present contribution are threefold: (1) to broadly outline the historicalbiographical setting of Kaljuvee’s and Reinwald’s research and their pioneer concepts on the Estonian impact crater site, (2) to summarize and partly correct opinions on their contribution to knowledge of European meteoritic structures, and (3) to present for the first time the original ( partly obsolete) Kaljuvee’s 1933 views on principal issues of the Earth history in its planetary setting. We eventually provide English translations of the key excerpts of Kaljuvee’s dissertation, as Supplementary Material
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