Abstract Large twin ring structure revealed in NE Asia with the map analysis: A new look at Yana and Indigirka river basins and the adjacent mountain ranges  George Burba Vernadsky Institute of Geochemistry and Analytical Chemistry 19 Kosygin St., Moscow 119991, Russia Email: burba@online.ru
Purpose
A search have been undertaken to evaluate if there are large ring structures on the Earth with diameter 300 to 800 km. Such structures could be terrestrial counterparts of large ring structures on the planet Venus termed Corona (pl. – Coronae). Corona-type structures on Venus have been revealed with radar (SAR) image data obtained from the Venus orbiters. Most of such type features on Venus consist from a ring of mountain ranges, which encircle a plateau area in the central part of the ring. The central, intermountain plateau is usually on the lower topographic levels, than the mountain ring, but on the higher levels than the plains outside the ring. If similar structures exist on the Earth it could be compared with their counterparts on Venus to be investigated through a comparative interplanetary analysis. The purpose of such analysis is to understand the geological/tectonic mechanisms of the formation of such large structures on the planets and the influence of such structures on the other components of the environment, such as atmospheric phenomena on the both planets, either on the river net patterns on the Earth. Results Analysis of the general (small-scale, synoptic) topographic maps and small-scale space images from the different satellites has been undertaken. About a dozen of large ring structures were recognized. And only in one case there have been found a structure, which consists from two adjacent rings. This twin ring structure is of a special interest, as it could bring knowledge on the evolution of giant mountainous ring ranges. The twin structure is located in the North-East Asia, in Russia, between Lena River mouth and Magadan coast of the Sea of Okhotsk. It spreads in NW-SE direction and consists from two similar ring structures, which were named by us Yana Ring Structure (YRS) and Oymyakon Ring Structure (ORS) after Yana River and Oymyakon settlement, located within each of them. YRS occupies north-western place, and ORS is on south-eastern place. Each structure has about 700 km in the outer diameter (i.e. between the mountain rim feet). YRS is located between 63 and 70°N, 125 and 140°E. Its rim crest diameter is about 500 km.Western half of its mountain rim consists of Verkhoyansky Range and the eastern part consists of Chersky Range (its segment west from Indigirka River). The inner part of the structure is the basin of upper Yana River. The circular outlines of YRS are marked with the large river valleys, located outside: Lena River (lower of Aldan River mouth), Aldan River (lower of Amga River mouth), Indigirka River (between 64 and 67° N latitude), and Selennyakh River (its N to S running segment). The typical altitudes of YRS mountain rim are 1000-2000 m. The central part of YRS – Yana Plateau – has typical altitudes 400-600 m. The lowlands outside YRS have typical altitudes 50-200 m. ORS is located between 61 and 67°N, 136 and 151°E. Its rim crest diameter is about 400 km. NE half of its rim consists of Chersky Range (its segment east from Indigirka River) and the SW part consists of Suntar-Khayata Range. The inner part of the structure is the basin of upper Indigirka River. The circular outlines of the inner part of ORS are marked with the Indigirka and Nera river valleys. The outer part of ORS is outlined with Moma River valley. The typical altitudes of ORS mountain rim are 1500-2500 m. The central parts of ORS – Oymyakon Plateau and Nerskoye Plateau – have typical altitudes 1000-1200 m. The lowlands outside ORS have altitudes 100-200 m. The highest topographic mark along the ORS rim is Pobeda Mountain (3147 m) in Chersky Range. It is also the highest point of the whole NE Siberia mountain country (eastward of Lena River), as well as of the whole Northern Asia (northward of 55°N), excluding Kamchatka Peninsula volcanoes. Conclusions (1) The highest area of the vast mountain country in the North-East Asia consists of mountain ridges arranged as the two adjacent ring structures. Such evidence is a new look on the general topographic structure of the area and could be of importance for the conceptions of its geologic evolution. (2) The general topographic shape of each of these structures is a complex of high mountain rings (altitudes 1000 to 3000 m) with a lower, but still topographically high (400-1200m) plateau inside, and lowland plains outside (50-200 m). (3) In general YRS is somewhat lower than ORS, especially with its inner area. It could points that YRS might undergo another evolution than the ORS, either evolution is the same, but each of the couple structures is currently within the different stage of its geologic life. (4) The outer diameter of each structure is about 700 km. The rim crest diameters are about 500 km for Yana Ring Structure (NE in the couple) and 400 km for Oymyakon Ring Structure (SW one). Such diameters and the topographic patterns mentioned above are typical for the large circular features on planet Venus termed Corona. There are only 3 or 4 structures of such or larger size on Venus. The detailed comparison of the same-sized ring structures of the Earth and Venus looks to be fruitful for the search of similarities and/or differences in the geologic histories of the structures on the two planets. (5) The seismic belt of Moma rift, a part of the global rift system, follows along the NE halves of the mountain rims of the two large ring structures. (6) Climatic consequences. Weather observations at Verkhoyansk on Yana river, near the center of YRS, and at Oymyakon on Indigirka river, near the center of ORS, have determined as early as in 1930s that these areas are the coldest places at the Northern hemisphere of the Earth. Now it could be explained that both these cold poles are located within the lower areas at the central parts of large ring structures (intermountain basins), which works as a giant “cold traps” being enclosed within a ring wall of mountain ridges. |