gonvanian
The Gonvanian is a geological period that lasted from approximately 470 to 458 million years ago, during the Ordovician Period. It is named after the Gondwana supercontinent, which was located in the southern hemisphere during this time. The Gonvanian is characterized by the formation of extensive shallow seas that covered much of the Earth's surface, leading to the deposition of thick sequences of carbonate rocks. These rocks are often rich in fossils, providing valuable insights into the marine life of the period. The climate during the Gonvanian was generally warm and humid, with high levels of atmospheric carbon dioxide. The period is also notable for the appearance of the first trilobites, which became one of the most diverse and abundant groups of marine invertebrates. The Gonvanian is followed by the Homerian, another subdivision of the Ordovician Period.