Mega Tsunami of the World Oceans: Chevron Dune Formation, Micro-Ejecta, and Rapid Climate Change as the Evidence of Recent Oceanic Bolide Impacts

Abstract

This paper deals with the physical and environmental effects resulting from oceanic impacts by sizable comets, and the rates and risks associated with such cosmic impacts. Specifically, we investigate two sets of probable oceanic impact events that occurred within the last 5,000 years, one in the Indian Ocean about 2800 BC, and the other in the Gulf of Carpentaria (Australia) about AD 536. If validated, they would be the most energetic natural catastrophes occurring during the middle-to-late Holocene with large-scale environmental and historical human effects and consequences. The physical evidence for these two impacts consists of several sets of data: (1) remarkable depositional traces of coastal flooding in dunes (chevron dunes) found in southern Madagascar and along the coast of the Gulf of Carpentaria, (2) the presence of crater candidates (29-km Burckle crater about 1,500 km southeast of Madagascar which dates to within the last 6,000 years and 18-km Kanmare and 12-km Tabban craters with an estimated age of AD 572±86 in the southeast corner of the Gulf of Carpentaria), and (3) the presence of quench textured magnetite spherules and nearly pure carbon spherules, teardrop-shaped tektites with trails of ablation, and vitreous material found by cutting-edge laboratory analytical techniques in the upper-most layer of core samples close to the crater candidates.Although some propose a wind-blown origin for V-shaped chevron dunes that are widely distributed around the coastlines of the Indian Ocean and in the Gulf of Carpentaria, we have evidence in favor of their

Risk–Risk Tradeoff Analysis of Nuclear Explosives for Asteroid Deflection

“…Chapman and Morrison () estimate a 10 −6 annual probability for asteroids of diameter 2 km or larger. Recent research proposes that asteroid collision probability estimates are significantly underestimated due to undercounting of hard‐to‐detect ocean collisions (Gusiakov, Abbott, Bryant, Masse, & Breger, ), but this proposal has been disputed on scientific grounds (Bourgeois & Weiss, ; Goff, Dominey‐Howes, Chagué‐Goff, & Courtney, ).…”

“…The current literature lacks consensus on how severe the tsunami would be. Gusiakov et al (2010) propose that several massive asteroid-caused tsunamis have occurred in recent millennia, but this proposition is hotly disputed (Bourgeois & Weiss, 2009;Goff et al, 2010;Pinter & Ishman, 2008). Other studies suggest that asteroid-caused tsunamis are much less severe (Gisler, Weaver, & Gittings, 2011;Korycansky & Lynett, 2005).…”

High‐energy inundation events versus long‐term coastal processes – room for misinterpretation

“…Abbott et al, 2007b). According to Abbott et al (2006Abbott et al ( , 2007c and Gusiakov et al (2010), such high-magnitude tsunamis cannot be caused by earthquakes, but by submarine eruptions, submarine slides or oceanic impacts, whereas the impact theory is favoured (Abbott et al, , 2007aMasse et al, 2006). Currently, the (mega-)tsunami hypothesis is challenged by several authors who argue that hydrodynamic aspects of tsunami propagation and inundation cannot produce such large-scaled sand bodies, consequently arguing in favour of an aeolian chevron origin (Blakeslee, 2006;Bourgeois & Weiss, 2009;Gramling, 2009;Garcia Garcia et al, 2012;.…”

“…So-called 'coastal chevrons' are V-shaped sediment bodies, morphologically similar to parabolic dunes. However, some researchers suppose that chevrons are linked to gigantic tsunami overwash created by oceanic impacts, amongst others, due to their dimensions and height above sea level Abbott et al, 2006Abbott et al, , 2007aAbbott et al, ,b,c, 2017Masse et al, 2006;Scheffers et al, 2008a,b;Gusiakov et al, 2010). This hypothesis neglects a possible aeolian genesis.…”

The Archaeology of Cosmic Impact: Lessons from Two Mid-Holocene Argentine Case Studies

“…There has also been significant recent work with the hypothesized late Holocene Chiemgau crater field in southern Germany (Ernstson et al 2010;Rappenglück et al , 2011, and a hypothesized Mesopotamian/Near Eastern impact event around 4.2 cal ky BP (Courty 1998(Courty , 2001Courty et al 2008). Masse and colleagues (Masse 1998(Masse , 2007Abbott et al 2007;Gusiakov et al 2010) have hypothesized and modeled that the universal myth of the "great flood" was the result of a deepwater Indian Ocean comet impact around 4.8 cal ky BP.…”