Large Craters of North America

What are the largest and earliest craters in North America? These are the fifteen that appear to be most important and obvious. The purpose here is not to defend their existence, a gravity map is provided for each one so the reader can recognize their individual energy signature. They are the “new kids” on the block, I want to introduce them and share a little bit about why I want to know them, and let you start to know your neighbors. Before we can make friends of them, we need to start to trust them.

Figure 1: For the author, the search for the big and early craters started with the Gulf of Mexico crater. The more I studied it, the more basin like it looked. If a huge bowl shaped pit had been excavated by a crater, the Gulf is the classical cratering pit. Its sedimentary layering even gives an understanding of fallback and washback ejecta. But, it is deep with information and much more research is needed.

Figure 2: When I started to study the Gulf of Mexico, I only considered the bowl to be the Gulf of Mexico crater, but the sediments extend as far north as the 7-8th ring, southern Missouri, and the original crater rim (OCR) may be as far north as Arkansas, about ring 9. The small Chicxulub crater on the Yucatan shelf is nothing compared to the much larger Serranilla crater that formed Yucatan Peninsula, Cuba, the Cayman Trough, and much of the Caribbean Sea.

Figure 3: The next crater I recognized was the Bermuda. I was curious how Florida came to be protruding into the Gulf of Mexico crater. The Bahama Islands are laying in a 30 km wide portion of very deep water, “Tongue of the Ocean” that I identify as a Release Valley just inside the Original Crater Rim-ring that contributes to Cuba, Florida, and the Appalachians.

Figure 4: The outer rings of the Bermuda crater also contribute to the Mid Continental Rift, red section under the 4-ring, the Front Range of the Rocky Mountains in Colorado, and extending its up-thrust to the High Plateau of Mexico between the Sierra Madre Oriental and the Sierra Madre Occidental.

Figure 5: The Keys crater lie under both the Gulf of Mexico and Bermuda craters. Fractures from it defined the Sabine Block of the western gulf and the eastern Texas area. The elevated heat the Keyes crater put into the substrate combined with the Gulf of Mexico crater’s heat to allow the Bermuda crater to push Florida up in a gneissic dome instead of a rocky mountain.

Figure 6: Being a relatively early crater, much of the energy signature of the Keyes crater is swamped by later cratering. Yet, we can see how the western edge of the Gulf and the southern arc of the Sierra Madre Oriental conform to it. Later craters do not obliterate, just add their energy envelopes to the ripple pattern. Can you see the blue ring inside the sixth-ring and under the fifth-ring?

Figure 9: The Alvord crater made the second contribution to the Sevier Orogeny, but its second and third ring extend too far into Wyoming to be the major contributor. The Great Basin at the center is all that remains of the cratering basin. Looking between the fourth and fifth rings, the white squiggly line is the path of the Colorado River through the Grand Canyon, and those rings extend up into Wyoming as the Intermontane and Bighorn Basin. These are areas of the Rocky Mountains with raised topography and extremely shallow Moho in the crust. The adiabatic response of the blue ring is why.

Figure 8: The Gorda’s ring structure was first recognized off of the coast in the slight bend and wide trough that later formed in the center few rings. The Gorda’s heat contribution allowed the far annulus from the later crater to have a greater expression with in those rings.

Figure 10: The wide area of dark blue between the third and fourth ring is obvious in this gravity map. This is what I refer to as a Release Valley, the adiabatic response zone following the shock wave. It forms as the wave moves from the high energy compression wave to the low energy of the expansion release-wave portion of the energy signature.

Figure 11: The third crater adding to the Sevier Orogeny is the Blowout Mountain crater. It is the crater which left the surface traces of the Sevier Thrust Belt at the western edge of Wyoming and down across Utah. It is also the major thrust behind the Kaibab Uplift of the Grand Canyon.

Figure 12: This stacking of the three thrust from three different cratering events within roughly the same area is the source behind the idea that the Sevier orogeny is a “thick skin” mountain building process going deep into the Precambrian rocks, reactivating original Precambrian faults. The narrow dark blue band just inside the sixth-ring, which cuts off the south end of the Sierra Nevada, sets the Blowout Mountain crater apart from the Alvord crater. They were not the same thrust.

Figure 13: Tatanka is the Lakota word for the buffalo that roamed the area. The major sedimentary and hydrocarbon Williston basin is indicated. The peculiar high spot in the western edge of the basin, the Bearpaw and Little Rocky Mountains, represents the central-peak or peak-ring of a complex crater on the moon.

Figure 14: The rings of the Tatanka crater are recognized by the blue ring just inside the third-ring and sixth-ring. The fourth-ring seems to be the next energy events in the red area of the Mid Continental Ridge after the Bermuda crater.

Figure 15: The Maka Luta, Sioux words for “red earth,” crater is possibly the most important crater for the US. It defines the “foundation” of this portion of the continent. It’s the up-thrust defining the continental shelf on the Pacific, Atlantic, and Gulf coasts. The first-ring again defines the Front Range and the western limits of the Denver-Julesburg Basin, which is the eroded remnant of the impact basin.

Figure 16: With added information, outside the first ring’s Denver- Julesburg basin, the Maka Luta crater defines several important hydrocarbon basins including the Powder River, Bighorn, Mowry, Niobrara, Greater Green River, Uinta, Mancos, Hermosa, Paradox, and San Juan Basins. This suggest hydrocarbons have their primary source from the deep mantle rather that fossil organics. Looking at a map of the Sauk Megasequence finds it is defined by the Maka Luta’s eighth-ring. This includes the Tapeats Sandstone of the Grand Canyon region.

Figure 17: The Foxe crater is one of the largest mappable craters in North America. The tenth-ring largely defines the Canadian Craton and also the northern reaches of the Sauk Megasequence.

Figure 18: The center of the Foxe crater appears primarily blue, and becomes deep blue inside the sixth-ring. If the reader would care to compare it with the gravity/GRAIL view of the lunar South Pole-Aitken crater’s center, there are several remarkable visual similarities. Tomographic sections through this area shows the low gravity blue extends downwards between 300-500 km, which is well through the lithosphere and asthenosphere. These large early crater show that it is not the mountains that have very deep roots, but the craters.

Figure 19: Very early craters are challenging to identify, but the Pedregosa crater suggest it is a very early one. This is based on its identification as the center for concentric expression in the Pelusiam Megashear of North Africa. That a point could be recognized as having a small circle relationship to a linear half a globe away suggest a great coincidence or a point application of a huge shear force, such as a very large impactor.

Figure 20: The best recognition clues for the Pedregosa crater is the blue areas just inside several of the white ring linears. The one just inside the third-ring is most pronounced, including a significant portion of the northern reaches of the Gulf of California.

Figure 21: The MCR crater is named for the Mid Continental Rift that it contains. The Tatanka and Bermuda craters have been mentioned as contributing their energy signature to the Mid Continental Rift. While I drew rings for both of those craters that align with the Mid Continental Rift, the dark blue area along both sides of it suggest it was the release valleys/expansion waves that aligned. One other “chance occurrence” is the alignment from the Ipojuca crater, which is certainly a release valley expression. The Mid Continental Rift is believed to represent a failed rift across the central partion of the continent. I propose it is a buried trench like those on the sea floor that represent release valley expressions, not rifting.

Figure 22: The visible high gravity expression of the Mid Continental Rift is exactly as long as the diameter of the second-ring of the MCR crater. I would refer to this as the Open-ring that would correlate with the rebounded crust under a lunar crater. Then the Mid Continental Rift would correspond to the Mascon (Mass concentration) found in many of the larger moon craters. It has been broken up, twisted, and shaped by several later smaller craters. Towards the eastern sea coast, the MCR crater had a remarkable effect on the final shape of the Appalachian Mountains.

Figure 23: The “Aguj de Anahuac” crater was chosen to mean “Pit of the ancient Mexican people”. It arrived after the Gulf of Mexico crater, and shaped much of Mexico, pushing it back towards the gulf.

Figure 24: Aguj de Anahuac crater emphasizes the major blue/low gravity valley that underlays most of western Mexico. This crater has little to do with that trough of low gravity but crosses it. It shows up as a thrust fault regularly in the midcontinent region, but has some of its most conspicuous energy signature showing on the Eastern Pacific Ocean floor just south of the center, not visible here.

Figure 25: Having its center in the Irminger Sea, between Greenland and Iceland, the Irminger crater is the most distant crater from the North American continent. Its timing may have coincided with the Tatanka or the Maka Luta. It comes up repeatedly in trying to map thrusting linears in the central continent, and is a major contributor to the southeast-northwest portion of the New Madrid, Missouri earthquake zone.

Figure 26: The third-ring of the Irminger craters has some gravity ridges that look strikingly similar to the Mid Continent Rift. It would be an interesting study to see if they also had some structural similarity. The eighth-ring is concentric to the Canadian Rocky Mountains. The Tasman Sea crater seems to be the source of much of the up thrust in the Canadian Rockies from the southwest, but it may be that the Irminger crater adds to that up thrust from the opposite direction as it does several times across Colorado, Utah, Wyoming and Montana when viewed is much greater detail. Two to three linears around the Grand Canyon appear to conform to segments of the Colorado’s path. This suggest it may be a significant contributor forming Grand Canyon faults.

Figure 27: The Great Beaufort is another crater that seems rather far from North America. It arrived very near the time of the Maka Luta and Foxe craters because it is a third crater that made a significant contribution to sandstone deposits in the north of Canada and Alaska in the Sauk Megasequence. The Great Beaufort crater also seems to be the energy source behind the Franklin Large Igneous Province that opened up some of the Foxe crater’s faults as extrusive conduits for the lava. This suggest the Great Beaufort impact may have occurred only hours to a day after the Foxe cratering event.

Figure 28: The Great Beaufort crater was after the Gordo crater. The fifth-ring coincides with the wide trough just off the California coast that I proposed was highly visible because it had occurred within rock that the Gordo crater had already heated. That fifth-ring forms a speckled pattern all the way across the continent, and the sixth-ring defines a section of the Atlantic Ocean’s Continental shelf.

Figure 29: The Caribou crater is the smallest crater considered here, but it forms the island studded Pacific Ocean edge of British Columbia, both Vancouver Island and Haida Gwaii. But, although Caribou crater contributed to the edge of the continent, it did not contribute to the perimeter of the Sauk Megasequence. This may mean that it followed the Fox and Maka Luta craters by a day or more.

Figure 30: The most obvious indication of the positioning of the Caribou crater is the third, fourth, and fifth-rings interaction with the Cordilleran. The compressive high gravity ridges under the white rings are all paired with blue rings on their inside edge. The sixth-ring is bordered with blue on much of its distance across the midcontinent, and even when the color is all blue, as in Canada, there is a lighter blue just under the white ring signally a slightly higher gravity in that area.

Figure 31: Although I have introduced each of these craters one at the time, we must never forget they are a gang, and when we look at any single geomorphic characteristic of our Earth, we may be looking at the result of 6 or 8 individual energy thrust but acting as a gang. Sometimes the assigning of responsibility is relatively straight forward, but sometimes it is a Gordian knot defying separation into its parts.

Figure 32: Looking at them as a gang, does not a gravity map resemble a quiet pond’s surface which has had a couple of handfuls of pebbles tossed into its depth? Trying to figure all of the pattern out mathematically may stump even the largest supercomputer. Yet, taken one-at-a-time, and with a minimum understanding of how the ripples interact constructively and destructively, we may be able to follow a ring enough that our confidence is established and a center allows us to expand and integrate much of the energy signatures into a pattern of work accomplished. A confusion of circles can be decomposed to understand the implications of the pattern.