What was the Cambrian Period?

The Cambrian is the beginning of the Phanerozoic, about 542 million years ago-485 million years ago. The previous period was the Neoproterozoic Icara period, and the latter period was the Ordovician period.

The name comes from the UK

During the Cambrian, hard-shelled animals first appeared in large numbers, many continents were flooded by shallow waters, and the supercontinent Gondwana was forming near the Antarctic. ^[3]

General in traditional rock stratigraphy

The Cambrian life explosion was called a major unsolved case in paleontology and geology. The Cambrian life explosion has plagued academia and other academic circles since Darwin. About 600 million years ago, the Cambrian period was called geologically, and most invertebrates appeared in just over 20 million years. This kind of invertebrate fossils (arthropods, molluscs, brachiopods and link animals) appeared in the Cambrian strata almost "simultaneously" and "suddenly" in more than 20 million years. The phenomenon that no animal fossils can be found in the more ancient strata before the Cambrian for a long time has been called "Cambrian life explosion" by the paleontologists, or "Cambrian explosion" for short.

Geological age

Darwin mentioned this fact in his book The Origin of Species and was confusing. He believes that this fact will be used as strong evidence against his theory of evolution. But he also explained that the ancestors of Cambrian animals must have come from pre-Cambrian animals, which were produced after a long evolutionary process; the "suddenness" of Cambrian animal fossils and pre-Cambrian animals The lack of fossils is due to incomplete geological records or submerged old formations in the ocean. This is the "Cambrian Life Explosion" that is still listed as one of the "Top Ten Scientific Problems" by the international academic community.

According to traditional and classic biological theory, that is, Darwin s biological evolution believes that biological evolution has undergone a long evolutionary process from aquatic to terrestrial, from simple to complex, and from low to advanced. The slow rolling of each wheel is gradually realized. Scientists have put forward various hypotheses to reveal the cause of the "Cambrian Outbreak". Researcher Chen Junyuan proposed that Cambrian biological mutations have a very obvious spontaneous evolutionary behavior; Professor Shu Degan proposed the "Cambrian warm water and cold water two ancient biogeographical divisions" hypothesis, etc., but there is no clear, conclusive evidence, Convincing explanation.

The Earth s rupture theory believes that the snowball Earth s rapid rise in geothermal temperature after the ice age is the real cause of the Cambrian life explosion. The Snowball Earth theory believes that the Earth experienced 750 million to 580 million years ago. An extremely serious and long ice age, the Varangir Period, when not only the land was completely covered by glaciers, but also the ocean surface was completely frozen. Liquid water was supported by heat from the earth's core and existed under 1 km of ice. If viewed from space, the earth is completely a huge "snowball." The "snowball earth" hypothesis was first proposed by American geologist Dr. Joseph Kosvenck in 1992. ^[7]

Snowball earth

What is the basis of the "Snowball Earth" hypothesis? First, the earth has extensively developed one or more layers of glacial deposits called "icemas" between 600 million and 800 million years ago, which represents a global cold climate. The most famous glacial period occurred about 600 million years ago, and it has left reliable records on almost all continents today. Geologically it is called the Warenger glacial period. In any case, the glacial deposits of the same period can be found in the strata that have been well preserved on the earth for 600 to 800 million years. Obviously, this cold climate is a global event. Secondly, in the history of the earth, many data show that, between 600 and 800 million years ago, most of the ice deposits were deposited near the middle and low latitudes. In other words, it is near the equator and the equator, and it is also the main land distribution. Area. This data leads to the conclusion that a wide range of cold climates occur on and around the Earth's equator.

The theory of earth rupture believes that although life was formed 3.8 billion years ago, because the earth gradually became cold, until the temperature of minus 50 degrees in the "Snowball Earth" period 800 million years ago, the evolution of species was very slow. Why did the "snowball" thaw and become the earth like now? The theory of earth rupture thinks that 800 million years ago, due to the continuous decay of radioactive materials inside the earth to release heat, the earth exploded, causing a large amount of magma to blow out of the crust. As a result, the temperature of the earth has rapidly increased and glaciers have melted, and ice mortars have formed during this period.

The temperature of the earth has risen from minus 50 degrees Celsius in the Sinian period (800 million years ago) to the highest temperature of 58 degrees Celsius, which has risen 108 degrees in 800 million years. The average temperature of the earth naturally rises by 1.35 degrees Celsius every 10 million years . The theory of the earth s rupture believes that the temperature of the earth increased sharply 800 million years ago, which is very suitable for the reproduction of organisms and the rapid increase in the rate of evolution, so a Cambrian life explosion occurred.