The Onion Ring Hypothesis: A Model for Impact Geomorphology

I introduce the Onion Ring Hypothesis (ORH), to explain measurable, shared, and repeated bedrock and landform geometries that appear to reveal universal explosion patterns of shockwaves from cosmic impacts. In this paper I discuss, target rocks in known and researched structures: Vredefort Crater in South Africa, the Chicxulub structure in Yucatan, Mexico, and the Nördlinger-Ries crater in Germany. I developed this model in response to a challenge to describe the complexity of cosmic explosion patterns on the landscape in the simplest terms. In this case, my illustrations and images show how the ORH model rests on the concept of tessellation, the making of a tile-like pattern, combined with patterns generated from red onion slices to demonstrate the intersection of impact structures and substructures akin to raindrop ripples on a pond overlapping and spreading. The implications of this are profound: by embracing wave physics as this model demonstrates, it leads us to wonder if perhaps the natural landscape IS the cratered landscape. Much impact literature focuses on single impact’ structures, whether by asteroid or comet, and sometimes emphasizing how big the structures are. This reasoning unnecessarily restricts discussion to singular events, not a widespread impact fragment swarm. Data accumulates to show that signatures of impact generated signatures are not just in the northern hemisphere, as new research in South America has datable horizons of impact evidence corresponding to North American and European sites (2). Enough evidence has been studied that YDB scientists propose the black mat be a datum layer like the worldwide Iridium and Platinum-rich Cretaceous-Tertiary boundary denoting the extinction of all non-avian dinosaurs from the Chicxulub impact 65-66 mya (3). Since 2007 when I learned of the possibility of a cometary origin for the Terminal Pleistocene extinctions, the idea of a single bolide causing such damage and extinctions appears questionable. My focus is on the idea of the Earth passing through the tail of a large comet, wherein millions of fragments were likely to strike the Earth. The operative hunch is that for an impact event to cause that much damage, there must be visible, recognizable signatures on modern landscapes of impact origin. This hypothesis is supported by Wolbach, Ballard, Mayewski, etal who suggest that their findings of YDB data from sites in the US, Europe, and Central and South America, along with chemical and impact-related material in the Greenland and Antarctic ice sheets are heterogeneous, like YDB samples, and are consistent with the distribution of findings to point at impact swarms from a fragmented comet (4). The larger point of this discussion is in response to critics of the Younger Dryas Comet hypothesis, also known as the Younger Dryas Boundary (YDB) event, believed by supporters as responsible for the extinctions of 32 or more genera of megafaunal mammals during the terminal Pleistocene epoch. The remains of extinct animals such as giant ground sloths, Bison antiquus, North American camel, horses, saber tooth cats, mastodons, and mammoths, and stone tools of the Clovis people who hunted them are found below a carbon-rich “black mat”(3) (which I call a “burn layer”) containing impact signatures such as magnetic and/or nonmagnetic silicate, carbon, metallic spherules, impact glass, nanodiamonds and evidence of widespread biomass burning circa 12,850+/- 50 calendar years BP. Above this layer, the extinct Pleistocene animals and Clovis culture are not found, although some megafauna survived into the very early Holocene in isolated populations. YDB researchers point to accumulating data such as burn layers or “black mats” as a datum layer akin to the Chicxulub impact iridium layer of 65 mya. (1) Full disclosure: I am not a trained scientist, but a professional landscape architect and land use planner. It is my job to pay attention to landscape patterns for developable areas and those to leave alone. To support the impact swarm hypothesis, based on my own observations and reviewed literature in this paper, there must be geometries that show traces of cosmic detonations on or above ground. My discovery of the impact ring patterns in the Onion Ring Hypothesis led to asking where else this patterning occurs, leading to multiple ways impact dynamics are reflected in several mapping technologies.