The chain of cosmic catastrophes on Earth - fantasies of addicted scientists or the reality of the universe, which is neglected? Vyacheslav Konstantinovich Gusyakov, Doctor of Physics and Mathematics, Doctor of Physical and Mathematical Sciences, Head of the Tsunami Laboratory of the ICMiMG SB RAS, in his article gives evidence of rapid global climate changes that have occurred on Earth in the recent geological past, and reflects on their possible causes
The most ancient meteorite crater is considered to be Suavjärvi, which is located in the north-west of Russia, in Karelia. Its age is determined at 2 billion 400 million years. Over time, the crater was filled with water and became a wonderful lake, a place of pilgrimage for fishermen and tourists. The crater diameter is 16 km.
Major natural disasters in recent years - the March 2011 earthquake in Japan, the December 2004 tsunami in the Indian Ocean, the Kashmir earthquake in October 2005, Hurricane Katrina in August 2005 in the United States, and Pakistan's flooding in August 2010 - have attracted attention the general scientific community to the problem of their prediction and assessment of the possible risk. These disasters, however, despite all their destructive effect and a large number of victims, are still regional in scale and stand out from the general row of natural disasters only in a very short geological and even historical time interval - one to two hundred years. Going beyond this time frame leads to an awareness of the possibility and reality of natural disasters, which are much larger in terms of their energy and spatial scales,which took place in the recent geological past of the Earth and, therefore, are quite possible in the future.
The largest climatic catastrophe that covered almost the entire northern hemisphere of the Earth at the Pleistocene / Holocene boundary (about 12,900 years ago), pronounced climatic anomalies recorded by annual tree rings, the presence of anomalous layers in lake sediments and drilling columns for Greenland and Antarctic glaciers in 4370, 3195, 2354, 1628, 1159, 207, 44 BC, as well as 536-540, 1292-1295 and 1348 AD, were almost global in scope. Traces of these disasters have been preserved in the form of geological evidence (anomalous layers in lake sediments, buried soils and dunes, impact craters), biological evidence (the disappearance or appearance of new species of animals and plants in the area, anomalies of dendrochronological series), archaeological facts,indicating sudden migrations and desolation of habitual habitats. In the last decade, numerous evidences about unusual natural phenomena, scattered in chronicles, folklore, legends, traditions and myths of many peoples of the world, have also been introduced into scientific circulation.
TRUTH IS BORN IN DISPUTES
Due to the scale of the problem and the level of its interdisciplinarity, the question of the sources and mechanisms of the spread of these abrupt climatic anomalies, which had catastrophic consequences for contemporaries, is highly debatable. A significant part of the scientific community in certain disciplines (for example, in archeology and history) ignores their existence, considering data coming from other sciences to be fragmentary, contradictory and, therefore, unreliable. In other disciplines dealing with direct observations and quantitative measurements of various natural trends, the existence of such global anomalies is not denied, but opinions differ as to their causes. These include the eruptions of large volcanoes, dust storms, smoke from fires.
In recent years, more and more publications have appeared in print, including in peer-reviewed scientific journals, testifying to the reality of rapid and global climate changes that have taken place on Earth over the past 12-13 thousand years, and their significant impact on the Earth's biosphere and the course of the historical process. At the same time, at least for several major catastrophes that occurred 12,900, 4300–4500 years ago, as well as in 536–540 AD, the possibility of cometary and asteroid impacts is indicated as the most probable cause of the rapid changes that occurred during these periods. climate and human conditions. At the same time, the prevailing paradigm, widespread in the historical and archaeological sciences, is the belief that there is no direct evidence thatthat any cosmic influences influenced the course of the cultural and historical process, at least since the inception of writing, i.e. over the past five to six thousand years.
This point of view is also supported by representatives of the astronomical community dealing with the problem of collision collisions of the Earth with small bodies (asteroids) and counting such bodies in the Solar System. According to their estimates, the average frequency of collisions between the Earth and large asteroids is about one million years. Accordingly, the probability of a major cosmic catastrophe during the entire Holocene (10 thousand years) is about 1%. Geologists and climatologists, however, point to at least three climatic catastrophes during this period, with possibly cosmic causes. The likelihood of a major regional catastrophe like the Tunguska is estimated at about 0.001, i.e. its recurrence is once in a thousand years. At first glance, this looks quite realistic, but if you take into account,that the Tunguska catastrophe itself in 1908 passed almost unnoticed (although information about the Tunguska explosion got into Siberian newspapers, it became the property of the scientific community only many years later), such an estimate can be greatly underestimated.
END OF THE DINOSAUR ERA
Several currently actively maintained databases on impact structures contain information on approximately 200 reliable impact craters known on the Earth's surface. Several hundred more already discovered ring structures await confirmation of their impact origin. The age range of reliable craters is very wide - from the youngest crater field in the Sikhote-Alin, generated by the fall and destruction of the Sikhote-Alin meteorite in 1947, to the most ancient known - the 300-km heavily eroded crater Vredefort in South Africa with an age of 2.1 billion years.
The process of proving the impact origin of a specific ring structure is very laborious and sometimes stretches for many years. For example, for the famous Barringer meteorite crater in Arizona (USA), it took almost half a century. It took almost 70 years from the first identification of the 1.2-kilometer Zwang crater in South Africa to the recognition of its impact genesis (in this case, the problem was the presence of volcanic rocks inside the crater ring).
In this regard, it is interesting to recall the history of the discovery of the Chikskulub crater, the third largest among all known impact structures on Earth, and the identification of this cosmic catastrophe with the end of the era of dinosaurs. The very idea that the mass extinction at the Cretaceous-Paleogene boundary (about 65.6 million years ago) could have been caused by the impact of a large asteroid was first expressed in an article by Nobel Prize winner in physics Luis Alvarez, published in Science in 1980 year. In an article entitled "The Cosmic Cause of Extinction at the Cretaceous and Tertiary Periods," L. Alvarez et al. Analyzed the high content of iridium and other platinum group elements in a thin layer near this boundary in several long-known limestone outcrops in Italy, Denmark and New Zealand. Their assumption was thatthat the increased content of rare elements on Earth in this layer could be a consequence of the impact of a large asteroid that occurred 65.5 million years ago.
Estimates showed that in order to cause a global catastrophe, the asteroid had to fall somewhere within the equatorial belt, have a diameter of about 10 km and leave a crater with a diameter of about 200 km. Such large craters on land were not known at that time, and the authors assumed from the very beginning that it would not be easy to find. For example, due to the fact that the impact could have occurred on the ocean floor, the formed crater by now can be hidden under a thick layer of sediment or even completely disappear from the face of the Earth due to the subduction process.
However, the following year, at the conference of the American Society for Exploration Geophysics, a report was presented that the analysis of maps of gravity and magnetic surveys. carried out in the Gulf of Mexico by order of oil companies, made it possible to identify an area of unusual concentric anomalies, the outer of which reached a diameter of 200 km. The authors interpreted this structure as the remains of a large paleovolcano or impact crater, later named Chikskulub after a small Indian village on the northern coast of the Yucatan Peninsula. Further research, including drilling the structure, revealed many other signs of impact, up to the discovery of geological traces of a powerful tsunami that swept through the territory of what is now Texas.
The shock hypothesis of the formation of a ring structure on the Yucatan Peninsula was recognized by experts, and the Chikskulub crater was included in the reference base of impact structures maintained by the Planetary and Space Center of the University of Quebec (Canada). In 1991, in an article published in the authoritative journal "Geology", A. Hildebrandt and co-authors expressed and substantiated the idea that the Chikskulub crater is the very structure, the formation of which caused the catastrophic end of the Cretaceous period, accompanied by the mass extinction of the biota.
However, not all geologists and paleontologists agreed with this idea. As an alternative mechanism, it was proposed, for example, the hypothesis that dinosaurs died from abrupt changes in the composition of the earth's atmosphere caused by degassing of the earth's interior during the global episode of basaltic volcanism that began at this turn. It was then that the famous Deccan plateau arose, covering almost all of central India with a basalt cover.
THE BEGINNING OF THE MIDDLE AGES
The closest to us in time is the global climatic catastrophe that occurred on Earth in 536–540. AD These dates first attracted the attention of dendrochronologists in the 70s of the XX century, when the basic chronological series of anomalies in the rings of European oak was stretched for 2000 years. Later, when long series appeared for other continents, it became clear that the anomaly is of a global nature. Other anomalies were found in the analysis of the drilling cores of the Greenland and Antarctic glaciers. The ice layers in the corresponding time interval contained a sharply increased amount of ammonium and chlorine, which could indicate the widespread occurrence of acid rain.
Historically, this period proved to be one of the turning points in world history, marking the transition from the ancient world to modern history. David Kay in his book Disaster. The search for the beginnings of the modern world”, published in 1999, directly writes:“It was an unprecedented catastrophe for the entire period of written history. Suddenly, for no apparent reason, the Sun disappeared for a year in a dim darkness. Weather conditions across the Earth have changed dramatically. Droughts in some countries and floods in others, crop failures in Asia and the Middle East have brought many ancient cultures to the brink of collapse. The epidemic of the bubonic plague, which began in Africa, wiped out half the population of Europe. Within a few decades, the old world died and was replaced by a new world, much of the world we know today.”
Quite naturally, when searching for the cause of this catastrophe, the first suspicion fell on the eruption of a large volcano located in the equatorial belt. The problem, however, was that volcanologists could not point to a specific volcano that erupted during this period. The results of the analysis of bottom sedimentary columns also did not give any indication of the tephra interlayers in this time interval, which inevitably should have remained after a major eruption.
The most significant step towards unraveling the causes of this climatic catastrophe was taken in 2005 by Dallas Abbott, of the Lamont-Docherty Geological Observatory (USA). Studying bathymetric maps of Carpentaria Bay in northern Australia, the researcher discovered two circular depressions, Kanmare and Tabban, with a diameter of 9 and 12 kilometers, respectively. According to her hypothesis, they could be traces of a double cometary impact that occurred in the southeastern part of the bay. Analyzing the upper part of the drill cores from this part of the bay, D. Abbott was able to detect a number of features characteristic of high-velocity impacts (microspherules, tektites, high concentrations of iron, nickel and chromium).
A high-speed impact on the water surface even in a relatively shallow bay should have caused tsunami-type waves, the traces of which, in turn, could remain on the shores of the bay. Viewing the images, Google actually discovered on the nearby islands and on the western coast of the bay the presence of so-called chevron dunes, which, according to one of the hypotheses of their formation, are considered the result of the deposition of powerful water flows.
EVIDENCES OF THE GREAT FLOOD
The "Great Flood" disaster is one of the most famous in modern history. Geology as a science began with it, since the first naturalists-geologists tried to explain all visible forms of relief of the earth's surface by the influence of powerful water flows. With the accumulation of field observations, it became more and more obvious that the age of the Earth is much older than the 6000 years allotted to it by the Old Testament, and that its surface was formed under the influence of completely different geological factors. For a long period of time, the very existence of such a catastrophe in the history of the Earth fell into doubt. The return of serious scientific interest to this hypothesis occurred in the very last years, when it became clear that information about such a catastrophe, which took away a significant part of the then population of the Earth, is not only in the Book of Genesis,Sumerian legends (epics about Atrahasis and Gilgamesh), the ancient Indian poem "Mahabharata", but also in the legends and traditions of literally all the tribes and peoples of the world, whose mythology has been collected and translated into European languages.
The most complete analysis of the Flood legends was carried out by Bruce Massa of the archaeological team at Los Alamos National Laboratory in New Mexico (USA). In his report, made at the International Conference "Comet and Asteroid Hazards and the Future of Mankind", held on the island of Tenerife (Spain) in December 2004, B. Massé cited the results of an analysis of 175 legends and myths of various nationalities from 40 countries. They describe a global natural disaster, unprecedented in its strength and coverage of the territory, which ended in the death of most of the then population of the Earth. This disaster began with a strong atmospheric storm, preceded in many places by seismic tremors and fires, continued with heavy rain for many days and ended with a flood that flooded all the low-lying parts of the land. Most strikingly, the details of the description and the sequence of events (earthquake, fires, black skies, strong winds, atmospheric storm with thunderstorms, giant waves from the ocean, heavy rain for many days) often coincide in the legends of tribes who lived completely isolated from each other in Patagonia, Brazil, Mexico, North America, Iceland, Syria, Mesopotamia, India, Indonesia, New Guinea, Australia.
A detailed analysis of the texts of ancient legends and tales and the references to meteorological and geophysical phenomena contained in them, their time sequence and geographical distribution allowed B. Massa not only to put forward a hypothesis about the cosmogenic nature of this planetary catastrophe caused by the fall of a giant comet into the ocean, but also to indicate an approximate place Falls - the southwestern Indian Ocean near Madagascar.
The indications contained in many myths about the season (spring in the northern hemisphere) and previous astronomical phenomena (tailed comet, conjunction of five planets, partial lunar eclipse) made it possible to make an assumption about the possible date of this event - May-June 2807 BC. The strongest blow destroyed the underlying rocks of the earth's crust, throwing billions of tons of rock into the Earth's atmosphere, which after a short time began to fall to the Earth in the form of melt drops, which caused fires in the African and South American savannahs. The explosion caused a devastating tsunami that devastated the nearby shores of the Indian Ocean and in one way or another affected the coast of the entire World Ocean. But the most important thing is that the explosion evaporated and threw into the atmosphere huge masses of water, which within a day began to fall on the Earth in the form of continuous torrential rain,which turned the plains of all continents into solid lakes with peaks of mountains and high hills protruding from them.
SANDY DUNES OF MADAGASCAR
The work of B. Masse initiated a targeted search for underwater craters on the bottom of the Indian Ocean by marine geologists, and soon a potential underwater crater with a diameter of 29 km, named by its discoverer D. Abbott Burkle crater, was found near the place indicated by B. Masse. The crater is located at a depth of about 4500 meters and is practically not covered with bottom sediments, which indicates its young age. Based on the size of the crater, it could have arisen as a result of the fall of a comet with a nucleus about 1 km in diameter, which undoubtedly caused a devastating tsunami, one way or another affecting the entire coast of the Indian Ocean. The closest land area to the site of the fall is the coast of the island of Madagascar. It was in its southern part that chevron dunes with a penetration depth of up to 45 km and a splash height of up to 200 meters were discovered. The azimuth of the strike of the long axis of these structures directly points to the discovered Burkle crater.
In September 2006, we were able to visit this part of Madagascar and survey three of four dune systems, including the two largest located in the area of Fenambosi and Ampalaza bays. The very first field routes showed that the dunes are composed of coarse-grained unsorted sea sand with the inclusion of pebbles and debris that cannot be moved by the wind. White areas, clearly visible on Google imagery, are located in the coastal and most offshore and elevated parts of the dunes. They are the result of secondary wind erosion and represent the latest modification of the dune body under the influence of the constant southeast winds blowing in this part of the Indian Ocean.
Finds of shells and coral bases in the sandy layer also indicate the marine origin of the material. In sand samples taken in the dunes, numerous microfossils were later discovered, and the thin calcareous structure of their shells turned out to be practically intact, which could not have been in the case of purely wind transportation of these tiny shells at a distance of tens of kilometers from the coast. D. Abbott's analysis of the drill cores from three deep-sea wells close to the crater revealed other evidence of its cosmogenic nature - impact quartz, crushed grains of other minerals (feldspars, spinel) and even micrograins of pure nickel.
AT THE BOUNDARY HOLOCENE
The largest in scale was the climatic catastrophe that encompassed the entire northern hemisphere of the Earth, which occurred at the turn of the Holocene about 12,900 years ago, when a gradual warming that began with the end of the last ice age was suddenly interrupted by an event known as the cooling of the young Dryas, which lasted almost 1100 years old.
The event itself has been known to geologists since the end of the 19th century, but as to the cause of its occurrence, there were only guesses and assumptions. In 2006, a book was published in the USA, written by physicist R. Firestone and geologists A. West and S. Warwick-Smith, in which a new and rather unexpected hypothesis of the mechanism of the beginning of cooling was put forward and substantiated. The authors of the book, based on an analysis of a large set of data, come to the conclusion that the most probable physical mechanism explaining the entire set of astronomical, geological, archaeological and paleontological facts associated with a sharp change in the climate of the northern hemisphere in the era of the young Dryas is the impact of a comet on an ice sheet about one and a half kilometers, covering at that time the territory of Canada and the region of the great lakes.
The space catastrophe led to the death of not only the megafauna, but almost all animals weighing over 40 kg in North America and the rapid disappearance of the Clovis culture. The destruction of the glacier caused the release of huge masses of fresh water into the Atlantic and the Gulf of Mexico, accumulated in periglacial lakes as a result of the gradual melting of the glacier, which led to a change in the Gulf Stream regime and, accordingly, influenced the climate of all of Eurasia. The resulting fires in the prairies and forests of North America caused the atmosphere to smoke, which is confirmed by the sharply increased concentration of soot and other particles in the corresponding layers of the drilling columns of the Greenland Ice Sheet.
There are dozens, if not hundreds, of other observational facts from a wide variety of disciplines that are explained within the framework of the impact hypothesis, but it continues to be subject to fierce criticism from its many opponents. Literally every argument advanced by supporters of the cometary impact hypothesis is disputed. At the same time, critics, as a rule, do not bother with alternative explanations of the main facts underlying the hypothesis (a sharp change in the Gulf Stream regime, the presence of an interlayer of a coarse-clastic fraction in the bottom sediments of the Gulf of Mexico, the rapid extinction of the entire megafauna of North America, the sudden disappearance of the Clovis culture), leaving them and dozens of other evidence of dramatic climatic changes that took place in the northern hemisphere at the turn of 12,900 years ago, beyond the scope of discussion.
More precisely, some explanations for these phenomena are given or at least implied. This implies, for example, the hypothesis of "overhunting" as the reason for the disappearance of mammoths and woolly rhinos in Eurasia, but little care is taken of its factual substantiation, for example, by comparing the number of the then inhabitants of Eurasia, their nutritional needs and preferences, which are easily identified by the species composition of bone remains at the sites and the population of mammoths, which, according to some estimates, reached five million individuals. And it is clear why this is happening. As wrote (on another occasion) L. N. Gumilev, any attempts to formulate such hypotheses clearly demonstrate their inconsistency.
THE REALITY OF THE SPACE THREAT
The problem of collisional collisions of the Earth with asteroids and comets becomes more and more urgent as the history of such collisions in the Holocene is clarified. While most of the astronomical community does not believe in the reality of major impact events in the recent past, geologists point to the existence of at least a dozen young craters that formed on the earth's surface during this period. The largest of them are Kaali and Ilumetsa in Estonia, Um el-Binni in Iraq, Vabar in Saudi Arabia, Chimgau crater fields in Germany, Campo del Cielo in Argentina, Headbury in Australia, Svetloyar lakes, Lezhninskoe, Smerdyachye in Central Russia, Danilovo, Linevo, Small Baikal in Siberia. Only during the XX century, there were two large fireball explosions - Tunguska in the Siberian taiga in 1908 and Kuruk in the Brazilian jungle in 1930, which did not leave ground craters, but caused fires and continuous felling of forests over a vast territory.
The study of this problem is especially relevant for the Siberian region, given its size. On the territory of Siberia and the Far East, there are 11 confirmed and about 60 putative impact structures, including the 100-km-long Popigai crater, one of the largest on Earth. In 1947, a 70-ton Sikhote-Alin meteorite fell in the Far East, leaving crater craters on an area of up to ten square meters. km. In the last decades alone, two explosions of large fireballs were recorded over the territory of Siberia - Chulymsky on February 26, 1984 and Vitimsky on September 25, 2002 with TNT equivalent of at least 10 kilotons. In solving this problem, the potential of the Siberian Branch, which has the necessary set of scientific subdivisions for a comprehensive study of the problem of catastrophic impacts, can be fully used,threatening our planet from space.