QUOTE (GeoMatt @ Mar 17 2017, 11:28 AM)
Gene - I'm ok with the use of the "38th Parallel Lineament", as the term predates any work Mr. Tonko has ever published on the feature. However, published peer reviewed literature (that I've come across) does not include several of the features that he includes in the lineament. I'm not sure how one would argue 38th Parallel Lineament vs. Tonko Lineament, my guess is that there would be some push back in peer review. If ever proven, I would see this as an extension of the 38th Parallel Lineament, not a renamed Tonko Lineament. The majority of features in the "Tonko Lineament" have been previously identified and the lineament named, and they would be attributable to the same impact event. But feature naming is well ahead of this discussion, you have to make a defendable discovery before you worry about the name.
I have no problem with the use of lineament with the 38th parallel structures. In fact, that aligns well with my previous definition of a lineament. For the sake of illustration, I have included the link to a Wiki article on the 38th parallel structures (also called 38th parallel lineament).
38th parallel structures - wikipediaThe quote below shows that there are associated geologic structures to the proposed impact sites.
QUOTE
....are a series of circular depressions or deformations stretching 700 km (435 mi) across southern Illinois and Missouri into eastern Kansas at a latitude of roughly 38 degrees north.
Rampino and Volk (1996) postulated that these structures could be the remains of a serial meteorite strike in the late Mississippian or early Pennsylvanian periods. Difficulty in determining the age of many of the structures and doubts about the exogenic origins of several of them leave some geologists skeptical of this hypothesis. As of 2016, only two of the structures, Crooked Creek (320 ± 80 Ma) and Decaturville (< 300 Ma), are listed as confirmed in the Earth Impact Database.[2]
There is evidence that at least some of them, such as Hicks Dome, are volcanic in origin. They are associated with faults and fractured rock, and are accompanied by igneous rocks and mineral deposits. Hicks Dome is a structural dome which has its central Devonian core displaced upward some 4,000 feet in relation to the surrounding strata. The dome has small associated igneous dikes around its flanks.
Like I said, drawing a line through these features and calling it a lineament certainly fits the definition I gave before. However, I do take exception with Mr. Tonko arbitrarily extending that line all the way to the Alamo impact site and calling that "line" a lineament. In my opinion, Mr. Tonko is doing nothing more than connecting dots together with a baseless inference that there are tectonic structures along his "lineament". That is akin to extending the Colorado Mineral Belt across the prairie until it intersects the Sudbury structure.
As far as I'm concerned Mr. Tonko can trademark the term if he is so smitten by it. That doesn't change the fact that he is misusing the term.
On a humorous note, the last paragraph of the Wiki article seems to want it both ways. The Earth is inferred to have insufficient mass to pull apart a comet like Jupiter did with Shoemaker Levy 9. They then finish by stating that, "serial impacts on the Moon can be seen in several chains of craters" which implies that the Moon was somehow able to do what the Earth most likely cannot. I'd be interested in seeing the results of some number crunching by astrophysicists regarding how the Earth could pull a comet apart so that the impacts would start in Illinois and end in Nevada.
For me the key to proving that the "Tonko Lineament" was caused by a disaggregated comet is not the fact that they lie on a "straight" line, but whether the ages of each of the potential impact sites can be correlated to the same time. The Wiki article indicates that the events could have happened anywhere from the Late Devonian to the Mississippian or Pennsylvanian periods. Mr. Tonko's hypothesis may be correct, but this discussion reminds me of Alfred Wegener and his Continental Drift theory. It was discredited until the hard science was conducted. Until then, I will remain a skeptical geologist who finds Mr. Tonko's hypothesis intriguing, but no more.
Slightly off topic WRT lineaments, but pertinent to the discussions on impact craters and diamonds is some recent research done by my old remote sensing professor, Dr. Keenan Lee. He is now an emeritus professor at Mines so he has the freedom to follow his intellectual curiosities. He has done quite a bit of research on the Tunguska event and the Popigai impact structure, both in Siberia. Here is an article on his MInes web page regarding the
Popigai impact structureFolks here may find the last section on "impact diamonds" intriguing.
Thanks for your input GeoMatt.