Pagodas suppress sea monsters! The killer of the Ordovician ocean: Sinian hornstone

The New Bride Stone in Nanyan, the thunderbolt presses bamboo shoots out.

If you moisten the roots with a spoon of water, when will it grow into a bamboo?

This is a poem written by Huang Tingjian, a famous writer and calligrapher in the Northern Song Dynasty, on a piece of strange stone. On the front of this strange stone is a "bamboo shoot". In that era when the emperor specially set up the "Huashi Gang" to collect rare treasures, literati and scholars also loved strange stones and antiques. But Huang Tingjian might not have thought that this is actually a fossil of an ancient creature called Sinian Hornstone.

Sinian hornstone, also known as Chinese hornstone, is one of the fossil organisms unique to my country. The so-called Sinian is the name given to my country by ancient India. The prefix sino in the Latin name Sinoceras of Sinian hornstone also refers to China. For example, the China Petroleum we are familiar with is called Sinopec.

Back to the point, the Sinian hornbill is related to the Nautilus, belonging to the Mollusca Cephalopoda Nautilus Subclass Orthocera, living in the Middle Ordovician about 460 million years ago, but they do not have a spiral shell, but a cone-shaped straight shell, shaped like a pagoda or bamboo shoots, with multiple chambers inside, which gradually expand. Their soft bodies use the first floor of the pagoda as a living room. Calcium is secreted at the end of the living room, causing the living room to move backward to form other chambers to adapt to the growth of the body. These chambers are filled with gas, also called air chambers, which can adjust the body's sinking and floating.

Like squids in the same class of cephalopods, they have multiple tentacles. In an era when there were no "squid-sucking" ichthyosaurs, they were quite capable of fighting. Some of them could reach a size of over 1 meter. In the eyes of their prey, they were as terrifying as the mythical Kraken. No matter whether it was a heavily armored trilobite, crustacean, or powerful horseshoe crab, they would overcome hardness with softness, grab the prey with their soft tentacles, and then bite it into their mouths and swallow it, without any sense of martial ethics.

However, its rise was rapid, and its fall was sudden. At the end of the Ordovician period, the first large-scale biological extinction event since the Phanerozoic occurred, which caused the extinction of 85% of the marine species at that time in a short period of time, and the marine ecosystem suffered a devastating blow. In addition, the straight shell has unavoidable defects: for example, it is difficult to turn when using the reverse thrust of the water jet, it is more likely to be damaged than the coiled shell, resulting in water leakage or invasion of bacteria, and there is no barrage protection on the port and starboard sides, so it is easy to "destroy the ship and the snail" when attacked. The drastic change in the environment made the Sinian hornstone, which has adapted to a specific environment and is highly sensitive to environmental changes, sadly listed on the list of standard fossils for comparison and division of Ordovician strata. The conditions for being on the list are not only "a family", but also a large number, wide distribution, and a short geological period.

Therefore, from ancient times to the present, a large number of Sinian hornstone fossils have been found in the Ordovician strata in central and southern my country. Folk discoverers often call them "pagoda stones" based on their appearance, and use them for ornamental purposes, or mysteriously for "suppressing evil spirits". The famous geologist Li Siguang also named the limestone strata containing Sinian hornstone fossils distributed in the Three Gorges area "pagoda group limestone". Although things are rare and valuable, the large number of Sinian hornstone fossils are still worth collecting by enthusiasts. After all, their unique scientific and aesthetic values ​​are difficult to measure with money.

The above is what we shared in this issue. See you next time if you are interested.