This article is about the Cretaceous extinction, but you want to know but you can't find it.
In what direction, at what speed and with what energy did the asteroid hit the earth? What is the texture of asteroids? How big is the crater? The shock wave that blew up a quarter of the earth? Global fire? 57 gale? 1 1 earthquake and 300-meter-high tsunami? How long did the impact winter last? How long did dinosaurs, dragons, pterosaurs and ammonites live after the impact? I believe this article will solve a lot of your curiosity about the extinction at the end of Cretaceous.
Impact theory
In the late 1970s, in a scientific team at the University of California, Berkeley, a Nobel Prize winner in physics with glasses: Louis. Walter. Alvarez put forward a theory. In the book "Earth's Sediments", he proposed that there was an unusually high iridium content at the Cretaceous-Paleogene extinction event (k-pg) boundary 66 million years ago. This heavy metal rarely appeared on the earth's surface, but it was very common in meteorites. So the idea that asteroids caused dinosaurs to become extinct was put forward.
Scientists were skeptical at first. Prior to this, the hypothesis usually believed that volcanoes or glaciers were the main cause of this mass extinction. However, a large number of iridium was found in 100 places where the Cretaceous extinction remains occurred, which supported Alvarez's view. Then, the last step for this theory to be recognized is to find this crater.
To this end, the Alvarez team tirelessly searched for a valley on the earth that met their requirements. 1June, 990, just 20 years after Alvarez made a statement, geologists discovered a huge crater in the northern corner of Yucatan Peninsula near the Mexican town of Chicxulubo, hence the name "Chicxulubo Crater".
Through the analysis of this crater and other relics, we can restore the moment of the catastrophe 66.043 million years ago and the scenes in the following decades.
Stage 1: On the eve of impact
At the end of Cretaceous, the world continued to get cold and the sea level dropped. The altitude peak of the Late Cretaceous was 50-70 meters, followed by the long-term decline of the Campa-Maastricht stage. From the early Cretaceous to the middle Cretaceous, there was a shallow sea: the famous "inland sea road in the west" covered the central and western parts of North America, but the continuous plate movement formed the Rocky Mountain, which led to the tensile fracture of the mainland and the retreat of the covered seawater. On the eve of extinction, there was only a small piece of inland sea. In the Paleogene, there was only a small piece of relic called cannonball sea.
At the end of Cretaceous, a large-scale volcanic eruption occurred in the lower part of western India. Volcanic eruption is mainly divided into three stages: the first stage takes place in C30n (stratum name), the second stage takes place in C29r (stratum name) and the third stage takes place in C29n (stratum name). The second stage may have started about 400,000 years before the Cretaceous-Paleogene extinction event (K-Pg), and it was the largest one, forming a Deccan shield with a volume as high as 80%. The global climate change related to Deccan volcano is likely to be related to the symbolic extinction of Cretaceous-Paleogene boundary, whether it is a good thing or a bad thing.
In any case, Deccan volcanism may have caused surface ocean acidification 200 kyr( 1kyr= 1000 years) before the Cretaceous-Paleogene extinction event (K/Pg), especially affecting organisms with calcareous shells, such as foraminifera, coccidia and ammonites. Fossil records in rocks prove that the number of marine invertebrates was gradually decreasing before the impact of the Hixulubo meteorite. On the eve of extinction, the flat-rotating ammonites have disappeared from the shallow sea area, and only a few fast-swimming types are distributed in the offshore.
There are also articles that show that the heat brought by Deccan volcano saved some lives from the long winter after the impact.
Phase II: Impact time (within 10 minute after impact)
66.043 million years ago, an asteroid hit the earth from the northeast with a horizontal inclination of 60 degrees.
The impact left a crater with a diameter of nearly 300 kilometers, indicating that it may be one of the largest impact structures in the solar system since the end of the early impact 4 billion years ago.
The results show that the reasonable estimated instantaneous diameter of chicxulub crater is about 170 km. The crater scale relationship obtained by calculation and experiment shows that the impact event depth is between17 ~ 20km, and the instantaneous crater depth is between 45 ~ 60km. Hiksulubo multi-ring basin with a diameter of about 300 kilometers recorded one of the biggest collisions in the sun since the late Big Bang nearly 4 billion years ago. On the surface of inner planets and satellites that have been fully studied, the only basin of the same size found is the Meade basin with a diameter of 280 kilometers on Venus. Since the development of multicellular life about 1 100 million years ago, the earth may not have experienced another impact on this scale.
This asteroid is composed of carbonate (calcite) and evaporite (anhydrite) and is 7.5 miles wide (about 12 km). The diameter required for asteroid impact is about 12 km and the velocity is about 20 km/s; It is required that the diameter of the comet is 10- 14 km, and the impact speed should be increased to 50 km/s, which is about 20 ~50 times of the bullet speed, and the released energy is more than 6.5438+0 million times of the maximum nuclear bomb explosion energy currently tested.
The location where the asteroid landed-Hiksulubo was a shallow sea covered by several meters of seawater on the day of impact. At the moment of impact, the surface material is lifted by the shock wave, resulting in a huge plume. Heat makes seawater evaporate instantly, and the expanding plume is mainly composed of evaporated water vapor in shallow water at first. The smoke column went straight into the sky, and there was a huge mixing inside. A chimney-shaped smoke column was formed above the impact site, including all kinds of smoke columns from shallow sea, sediments, organisms and later meteorites. Matter was thrown from the lower part of the plume to the upper part at a speed of several kilometers per second, and later, the smoke column began to expand horizontally.
About 30 seconds after the impact, the crater reached about one-third of the transient size, and the plume has exceeded the stratosphere (10km to 50km above the surface) and continued to expand, reaching three times the size of the impact crater.
Only a tiny part of the asteroid expands outside the impact port. After the asteroid hit the surface, it did not break immediately, but crashed into the upper mantle, instantly forming an instantaneous cavity with a diameter of about 100 km underground. Asteroids drill into the ground to a depth of 30-40 kilometers (some articles say that they can drill to a depth of 70 kilometers).
Then, a huge tsunami swept through the Gulf of Mexico, attacked the nearby coastline and radiated to the former Caribbean and Atlantic basins. When a tsunami occurred along the coast of the Gulf of Mexico, it was as high as 100 to 300 meters, and went straight inland 300 kilometers away, washing the seabed sediments to a depth of 500 meters.
At the same time, the explosion shock wave generated by the impact event radiated the whole of North America, causing 56-level gale near the impact site (the maximum wind level on the earth is 17, which is 200-220km/h, and the high-speed wind speed is 20km/h), scouring the soil and tearing up the nearby plants and any living things. The area with a diameter of about 3000 kilometers was destroyed by air explosion. (PS: radius of the earth 637 1.0 12Km, and the explosion propagation length is equivalent to a quarter of the earth).
The temperature of the plume rising from the crater is over 10000 degrees Celsius, which is twice the surface temperature of the sun, causing a huge fire within the range of 1500-4000 kilometers. Such a high temperature is devastating to animals living in this range. The thermal pulse is relatively short, lasting only 5- 10 minutes, so some creatures can escape this special influence if they are sheltered. When the impinging jet falls, the lava fire rain lasts for 3-4 days.
The impact also produced chlorine and bromine that destroyed ozone. More than five orders of magnitude of chlorine is mixed with bromine and other reactants and injected into the stratosphere, which is more than what is needed to destroy today's ozone layer. Nitrides produced in the atmosphere also have the ability to destroy ozone. The impact on the ozone layer may last for several years.
The third stage: Flame Earth
Land extinction pattern (hours-days)
Impact after the first hour >: The earthquake with the magnitude of 1 1 and the huge tsunami up to 300 meters are the main effects, that is, the so-called "fireball stage". The impact detonated tens of thousands of tons of rocks, and also caused the remnants of asteroids to be washed into the atmosphere, some of which entered the orbit, while others returned to the ground as dense burning meteors, including strong thermal pulses generated by the backflow of larger ejecta, which triggered global forest fires. Infrared spectrum shows that the global distribution of ejecta may lead to short-term large-scale atmospheric warming, and the rise of ground temperature will lead to spontaneous combustion of trees, which will burn more than half of the vegetation on the earth within a few weeks after the impact.
The fire may have originated in southern North America, but the global clastic layer on the Cretaceous-Paleogene extinction event (k-pg) boundary is enough to show that the whole terrestrial biosphere was burned. Preliminary simulation shows that the re-entry of ejecta into the atmosphere will lead to a global infrared pulse, which is enough to trigger a global fire within a few hours after the impact of Hixulub. The fire hypothesis explains the terrestrial survival mode of early Paleocene in North America, because all the surviving species had to avoid high temperature and flame underground or in water. Some areas are lucky. When the impact occurred, the site was covered by stagnant water, which became one of the few areas on American land that were not burned, leaving a site lacking charcoal and unburned organic matter.
Global wildfires have reduced most terrestrial ecosystems to ashes, resulting in a large number of animal deaths. In a short time, insects in North America seem to disappear, because in the fossil record of North Dakota, the frequency of leaves being destroyed by insects has dropped sharply. It is not clear whether these insects died directly from the high temperature flame of the impact event or because their host plants were killed. Groups with cave-dwelling characteristics, such as mammals, can provide them with shelter from high temperature in the first few minutes, thus avoiding extinction.
With the burning of plant and surface organic carbon, a large amount of carbon dioxide, CH4 and H2O are discharged into the air, some of which come directly from asteroids (carbonates) and the rest from the earth itself. The impact produced ejecta with a total volume of about 80,000 cubic kilometers, including 35-350 billion tons of carbon dioxide, 4-56 billion tons of sulfur and 20-65.438+04 billion tons of water vapor.
The impact event has changed the global environment, if not 1000 years, it will last for at least several years.
Sulfur-containing compounds may be the most important climate-active gases injected into the stratosphere. The amount of sulfur released by this impact is several orders of magnitude higher than that of any known volcanic eruption, and the erupting water is enough to cause sudden and significant disturbance to the earth's climate.
After the impact, the ejecta caused a strong warming of the upper atmosphere, and this effect may only last for a short time. After several hours, sulfate formed and remained in the stratosphere, and reacted with water vapor to form stable and long-lived sulfate aerosol. Aerosol disturbs the thermal state of stratosphere by absorbing long-wave radiation, cools the earth's surface and significantly disturbs the global climate for many years, so the atmospheric circulation is interrupted for several years.
Acid rain is a secondary product of impact events. After the impact, it may rain for days, months to years. First of all, the atmosphere became hot due to the impact event, which led to nitrate rain. The impact event produced about 1 10 15 mol of nitric acid rain, and about 3 10 15 mol of nitric acid was probably caused by the forest fire caused by the impact, while sulfuric acid was caused by the asteroid itself and its subsequent lava and forest fires.
The combination of sulfuric acid rain and nitric acid rain is not enough to acidify marine basins, but its impact on shallow water or poorly buffered estuaries and continents is complex. Even if all the sulfur is released in the impact, it seems unlikely that the acidification of seawater on the ocean surface will lead to the mass extinction of marine life. On the other hand, if the soil is not fertile and cannot buffer the acidification of groundwater, the consequences of acid rain may be very serious.
The fourth stage: the cold earth
Extinction patterns of waters and land (several days-two years)
After the first few days of high temperature and burning, the flame tends to calm down, but a bigger crisis is coming.
Aerosol produced by impact, soot and sulfate produced after impact reflect sunlight in the upper atmosphere, thus directly cooling the earth; Moreover, the organic smoke produced by burning organic fossils in forest fires absorbs short-wave radiation, preventing sunlight from reaching the surface, leading to a drop in surface temperature, temporarily inhibiting photosynthesis, and causing the global collapse of land and marine food webs.
The sunshine is reduced to 20%, which is probably the feeling. PS, spear arrow stone is the main (only) swimming member of "the last swimming animal community in Mesozoic".
The model simulation shows that the amount of sunlight reaching the earth's surface may be only about 20%, which means that the energy supply will be reduced by about 300 W m–2, resulting in a serious drop in the global surface temperature in a short time. In a short time, the temperature of the earth has dropped by several degrees to dozens of degrees. The resulting temperature difference may trigger large storms and hurricanes between the relatively warm ocean and the cold atmosphere, increasing the time for dust to drift in the atmosphere.
Uneven temperature distribution between land and sea will cause wind, which will increase the retention time of dust.
After several months to decades, the atmosphere stabilized and dust began to fall like raindrops and accumulate in the sedimentary environment. This includes PGE peak, which is a globally recognized trace element from asteroids, such as iridium. Compared with dust, sulfate has a greater impact on the environment. The impact of aerosols will lead to low ocean temperatures for decades, even though most of the dust has been removed from the atmosphere.
The aquatic environment is protected by water from heat and fire, but the marine environment and fresh water environment still show a huge scale of extinction.
In a few months to several years, maybe at least six months is a dark period, and the influence of winter leads to a large number of phytoplankton deaths around the world. Because aquatic ecosystem is different from terrestrial environment, it strongly depends on the output of daily photosynthesis, and the loss of phytoplankton is likely to cause catastrophic death and extinction of aquatic ecosystem. Other potential causes of extinction of aquatic ecosystems include environmental temperature and hypoxia due to lack of oxygen needed for photosynthesis.
In the ocean, under the influence of acid rain and light, diagenetic water beads grains with calcareous shells and planktonic foraminifera collapse at the collision boundary. Until the early Paleocene, their abundance was still very low, and the organic debris flowing to the seabed also decreased sharply, and it still did not recover about 3 years after impact (1 myr= 1 million years). The extinction rate of marine species supported by plankton at the boundary of Cretaceous-Paleogene extinction event (K-Pg) is the highest.
Jushi, the most diverse and abundant plankton predator in Paleozoic and Mesozoic, died out together with the giant canglong, plesiosaur and pliosaur that ate them. Then, in Paleogene, fish expanded to the niche they once occupied.
The cartilaginous fish lost about 20% families, and the bony fish lost about 10% families. Amphibians are almost extinct at the family level. All six late Cretaceous tortoises survived.
The slow recovery of photosynthesis means that hunger is the main reason for the extinction of marine species. The extinction rate of marine species is higher among pelagic species, because pelagic organisms are almost completely dependent on phytoplankton. Benthic organisms are more resistant to hunger, and the dead biomass at the bottom of the sea is consumed in the food chain based on corpses. Xanthomonas sp. is more susceptible to extinction than xanthophyll azo coral.
Hunger tolerance of multicellular warm-blooded animals ("cold-blooded animals") is a function of body size (Figure 1: Peters [1983, page 42]; (Raw data collected by Hammingson [1960]). Small invertebrates (10 lb to 10 mg), including zooplankton and some benthic invertebrates, have a life span of 8-20 days. The survival time of macroinvertebrates (1 00g to1kg) and other macrofauna (such as crustaceans, mussels and many other macrobenthos) exceeds the lower limit of the estimated recovery interval by 6 months. The largest temperature-changing animals, including extremely large invertebrate cephalopods, large fish and aquatic reptiles, can survive without food 1 to 3 years. Shanglong and black dragon, who swim fast and freely, may be warm-blooded animals with high metabolic rate and are more likely to starve to death.
Because of its high hunger tolerance, extinction has promoted the survival of some marine organisms, such as brachiopods. In the Mesozoic marine fauna, brachiopods became a secondary component, and they retreated to the cold water area, far away from the warm and food-rich offshore. Adaptation to cold can improve their survival ability in severe winter. Brachiopods feed on phytoplankton, bacteria, organic debris and organic molecules. They may have adapted to the lack of food, so their numbers in New Jersey and Denmark increased relatively before and after extinction.
In the ocean, sunlight disappeared for at least 6 months, and photosynthesis may have been inhibited for 2 years, but then phytoplankton production recovered rapidly. However, zooplankton will starve to death within 4 months after the impact, so when the light is restored, the complete food web will not regenerate immediately. Phytoplankton recovered immediately after light recovery, but the slow recovery of hungry zooplankton may still have a long way to go, delaying the recovery of all other animals in the ecosystem.
Giant Maastricht planktonic fish (> 5 meters long, > 400 kilograms) may feed on zooplankton and krill, not phytoplankton. Their huge size enabled them to survive two years of severe winter until the sun rose again and phytoplankton rebounded in the surface water. However, they can't wait for enough zooplankton and krill that feed on phytoplankton to recover.
Among these filter-feeding animals, ammonites are the main victims. Large-scale aptychoporan ammonite (a name for ammonite) lived in the body cavity of late Olivero and Hinsmest, with a length of about 65,438+0.65,438+0 meters. It is estimated that this living animal weighs about 6 kilograms and the limit of starvation is about 2 years. However, ammonite takes phytoplankton and zooplankton as larvae and will eventually become extinct due to the loss of zooplankton. On the contrary, the larvae of octopus and nautilus are non-plankton and carry a yolk bag to provide self-sufficient nutrition for the larvae. Similarly, some echinoderms such as sea urchins have evolved non-planktonic larvae, so both of them have been extinct.
Freshwater environment is affected by high temperature just like land, but water protects them. Only a few centimeters of water at the top will be affected by heat, and the slight influence will completely dissipate within a few weeks.
The energy burst caused by the impact and the subsequent fire may burn all the exposed carbon, but the underground organic carbon in stock can be transported to the freshwater ecosystem in the form of particles or dissolved. Of course, the mortality rate of inland waters is also high, but the extinction rate is lower than that of marine environment, which may be due to the better dormancy ability of freshwater groups and the higher aeration efficiency of river water to offset oxygen demand through rapid flow. Under the condition of moderate temperature, groundwater provides rich heat capacity, which offsets some effects of high temperature and cooling.
Almost all freshwater families are extinct only a few times, as opposed to land or sea. The Cretaceous-Paleogene extinction event (K-Pg) boundary was not extinct, and the extinction rate increased with the increase of offshore distance until 45% was in the open ocean.
Among 10 crocodiles in Maastricht, 5 marine families are extinct, 4 freshwater families are alive, and no freshwater family is extinct. Even larvae living in fresh water can survive at the K-Pg boundary, such as Anomalous Dragon (including Ceratosaurus in E Long) which lasted until Miocene. In fresh water, large reptiles (crocodiles, dinosaurs, turtles) may be big enough to resist hunger and extinction. Smaller vertebrates, including fish and amphibians weighing less than one kilogram, must rely on other survival mechanisms, especially dormancy. Surviving marine plankton, such as dinoflagellate, usually have the ability to form a dormant body, while plankton with high extinction rate, such as foraminifera and pebbles, usually lack a dormant stage.
In addition, the extinction rate of scavengers is very low in both marine and freshwater environments, but the mortality rate of scavengers in freshwater groups is lower than that in seawater because they can obtain more organic matter from updated soil.
The fifth stage: recovery stage
(Decades-thousands of years)
Aerosol and dust will slowly settle after several months to decades, and sunlight will return to the earth after six months to two years, reaching the level that can maintain photosynthesis. Then, the temperature began to rise.
Greenhouse gases such as carbon dioxide, methane and other organic molecules ejected by previous impacts helped to warm the earth. Gases such as carbon dioxide stay longer than dust and sulfate aerosols, and cause greenhouse effect after aerosols and soot settle on the ground and cool. Warming may occur after a period of cooling. Estimates of the degree of heating vary. According to the estimation of carbon dioxide data, the warming range of greenhouse effect is between 1 and 1.5 degrees Celsius.
After the impact, the ocean surface becomes the lowest temperature area, and the deep temperature is higher, just like the waters in winter; Fifty years after the impact, the surface temperature began to return to normal.
With the return of sunlight, the phytoplankton in the ocean and fresh water recover rapidly, while the recovery of zooplankton takes longer. However, on land, plants recover very slowly, because the growth and development cycle of rooted plants there is at least one year. In the area where the fire broke out, most plants were removed.
Pteridophyte is a pioneer species in some northern regions, such as the United States, Japan and New Zealand. In areas where there are no ferns, algae and moss are other pioneer vegetation types. In northern North America, the original vegetation was composed of several types of ferns and flowering angiosperms, forming a grassland. Now that pollinators have been eliminated, those plants with wind-borne pollination ability that do not rely on insects have a greater chance of surviving and not becoming extinct. Deciduous trees seem to have survived, better than evergreen trees in North America, probably because of their dormancy. Finally, the crown of the forest came back. Later, due to the development of beans rich in protein, the weight of the fauna recovered to a higher level. After13050ka (1ka =1000), the carbon cycle in the United States resumed.
In the ocean, with the restoration of light, the disappearance of predators and competitors, individual local groups began to invade other areas. For example, before the impact, the inshore foraminifera not only maintained its original environmental niche, but also settled in the ocean environment. The recovery of all geographical locations is different. For example, some mollusks expand faster near the impact area than in other parts of the world. Sedimentation-feeding bivalves survive, while other bivalves (carnivores and suspended predators) survive 38%-58%. Because there is no ammonite, in Paleocene, bivalves and echinoderms often formed large communities. But in New Zealand, it all flourished from the beginning. New Zealand's small marine fossil records prove that there was no mass extinction in this area at the end of Cretaceous. In fact, the number of biological species in this area has increased, probably because the cold current that led to the extinction of animals in other parts of the earth has changed here, which is conducive to the survival of species.
Stage 6: Traveler
Before the extinction of non-bird dinosaurs, there was little evidence that their diversity declined globally for a long time at the end of Cretaceous. Dinosaurs in the south of Hellfire River area survived, maintaining diversity and richness, without any signs of decline. Dinosaurs in Tripp Basin, Spain, survived, and were widely distributed throughout Maastricht, with diverse species, and did not decrease significantly or become extinct locally before the K-Pg boundary. Of course, the decrease in the diversity of large herbivores found in Cretaceous dinosaurs in North America may make the community more vulnerable to cascade effects. Combined with the impact events, we can conclude that dinosaurs, like pterosaurs, died of fires, tsunamis and storms in the first few days.
A group of late non-bird dinosaur fossils were found at 13 cm below the K-Pg layer. They are a group of dinosaur horn fossils, belonging to a herbivorous dinosaur and possibly to the famous Triceratops, so they may be the last extinct dinosaurs. However, dinosaurs that successfully crossed the k-pg boundary still exist.
Smaller theropod dinosaurs can hide in natural caves (caves, tree trunks, underwater/underground) and beside rivers and streams. The new evidence that non-bird dinosaurs burrowed makes at least some of these animals able to withstand the impact of disasters for a period of time. In 2003, the senior author (JDS) and his team first discovered the record of non-bird dinosaurs in the first stage of Paleocene on Chatham Island, 865 kilometers east of Christchurch, New Zealand, during an investigation sponsored by the National Geographic Society. The larger remains of theropod dinosaurs include theropod phalanges II- 1 (or III- 1), which are 18.5 cm long and 10.2 cm wide, and may belong to a medium-sized theropod dinosaur. Other bones (spine, part of tibia) represent this 4-meter-long dinosaur. Therefore, it is possible that there are smaller theropods in the forest areas of the southwest Pacific Ocean.
The dinosaur eggs discovered by Chinese scientist Zhao outside the boundary of Cretaceous-Paleogene extinction event (K/T) in Nanxiong area show that the meteorite impact theory is not applicable to dinosaur extinction in Nanxiong area. According to his research on dinosaur eggs, climate change has greatly affected the food chain and reproduction process of dinosaurs, leading to the gradual extinction of dinosaurs between 200,000 and 300,000 years, which is also a long-term continuation of non-bird dinosaurs.
The birds in Mesozoic had a similar situation. 17 ancient bird species within 300,000 years were identified at the K-Pg boundary, including anti-bird, fish bird, yellow bird and a bird similar to winged bird. Most of the birds described here are modern birds, not anti-birds.
These birds on the eve of the end of the world are the most diverse Cretaceous birds recently known, including smaller forms and some of the largest known birds in Mesozoic, although the size gap is smaller than that in modern times. The rich diversity shows that birds had large-scale radiation before the end of Cretaceous. But none of them are sure to have something to do with the new bird. One of the birds, C, is the only bird known to have successfully crossed the K-Pg boundary and lived to the new year.
Another kind with definite duration is ammonite. In the last 0.5ma in Maastricht area, ammonites still flourished, and all four suborders appeared in Mesozoic, including 6 superfamilies, 3 1 (subgenus) and 57 species. Recent data show that Ju Shi has been living on the border. Like dinosaurs, they did not disappear immediately after extinction.
A paper by Surlyk and Nielsen( 1999), the last chrysanthemum stone? Challenge the theory that ammonites died out at the end of Cretaceous, although they have no detailed evidence to prove that they survived. Their hypothesis was later supported by Marchalsky (2002), who discovered the famous ammonites and ammonites (both heteromorphic ammonites) at the end of the Cretaceous, although the number was far less than that in the late Maastricht era. Before them, some people published papers on Dennison's ammonite, but in the end they were all recognized as the result of redeposition. However, there are no other Cretaceous organisms around the ammonite this time, only algae, foraminifera and brachiopods with Cenozoic characteristics, indicating that the ammonite also extended to Denison, with an annual age of about 200kyr( 1 kyr= 1000). Similarly, black dragon and plesiosaur, which feed on them, may live here, but they may die because they are not hungry in the first two years. Arrow stone also lived in Paleogene and even lasted until Eocene.
Roveacrinids is a kind of deep-sea sea lilies which originated in the Middle Triassic and survived from Cretaceous to Paleogene, although it seems that the lilies have nothing to do with the great changes of marine biodiversity. In the Cretaceous-Paleogene (K-Pg) boundary extinction event, Roveacrinida, considered as the representative of sea lilies, became extinct during this period. However, the well-preserved Danian (early Paleocene) fossils in Poland prove that these sea lilies survived to the earliest Cenozoic. Similarly, there are the posterior teeth of corals, amphibians of earthworm lizards, amphipods of gastropods, Skeletonema costatum of anti-feathered crabs and bryozoa. Of course, none of these groups have lived through the lunar new year.
Mesozoic creatures ended with their final death.