The name Devon** is derived from the Devon region of England, the Devon county of Devon, England. At the beginning of the 19th century, the British geologist Ri.m.Cornwall, Ri.m.Conway) while studying the geology of the area, discovered a set of fossil-rich strata that he considered distinct from the Silurian strata, hence the name Devonian. Its geological layers are rich in fossils from the period. The Devonian period, also known as the Age of Fishes, spanned about 41.6 million years from 41.6 billion years ago to 35.9 billion years ago, the Devonian period was the fourth epoch of the Paleozoic Era, and it was also an important period in the evolution of life on earth.
The geological chronology of the Devonian is mainly based on the fossil record in the strata and the results of radioisotope age. The Devonian geological age is divided as follows:
1.Early Devonian epoch: about 41.9 billion to 39.3 billion years. During this period, the Earth's terrestrial and marine environment underwent significant changes, with fish and other marine life diversifying.
2.Middle Devonian epoch: c. 39.3 billion to 38.2 billion years. During this period, marine life continued to diversify and terrestrial plants began to evolve rapidly, forming the earliest forest ecosystems.
3.Late Devonian epoch: about 38.2 billion to 35.9 billion years. During this period, vertebrates began to land, amphibians began to emerge, and land plants continued to diversify, forming more complex terrestrial ecosystems.
In the Devonian epochs, the stratigraphy was mainly divided according to the distribution of fossil belts and the thickness of the strata. For example, in the Early Devonian, different strata could be divided according to the distribution of fish fossils; In the Middle Devonian, strata can be divided according to the distribution of plant fossils and coral fossils; In the Late Devonian, strata can be divided according to the distribution of amphibian fossils and land plant fossils.
Important geo-historical events
1.Tectonic movements: During the Devonian period, the Earth's crustal movements were relatively active, especially in the tectonic belt between land and sea, such as the Paleo-Tethys Ocean between the Paleo-Arctic and Paleo-Southern Continents. Large-scale tectonic movements, such as the Caledonian movement, occurred during the late Devonian period, leading to the closure of the Paleo-Tethys Ocean and the convergence of landmasses.
Reading cured my mental internal friction 2Biological evolution: The Devonian period was a period of rapid evolution of vertebrates and land plants. Fishes began to diversify in the early Devonian, and amphibians began to appear in the late Devonian. At the same time, land plants also showed a clear diversification trend in the Devonian, forming the earliest forest ecosystem.
Geological features
Crustal movement: The Earth's plate movements were relatively active during the Devonian period, especially in the tectonic zone between land and sea.
Tectonic changes: Large-scale tectonic movements, such as the Caledonian movement, occurred during the Late Devonian period, which led to the closure of the Paleo-Tethys Ocean and the convergence of landmasses.
Sedimentary environment: Devonian strata are mainly distributed in shallow sea and terrestrial environments, of which the sediments of the shallow marine environment are dominated by limestone and shale, and the sediments of the terrestrial environment are mainly sandstone and mudstone.
Inheritance and differences from the previous and subsequent eras
Silurian - Devonian: The extinction event that occurred in the late Silurian period caused the disappearance of many taxa, creating space for the evolution of Devonian organisms. In addition, in terms of tectonic movements, large-scale tectonic movements in the late Silurian period laid the foundation for the stabilization of the Devonian crust.
Devonian-Carboniferous: Large-scale tectonic movements in the late Devonian period laid the foundation for the stabilization of the Carboniferous crust. In addition, in terms of biological evolution, the evolution of vertebrates and land plants in the Devonian created the conditions for the diversification of Carboniferous organisms.