Silurian

Marine extinction intensity during the Phanerozoic
%
Millions of years ago
(H)
K–Pg
Tr–J
P–Tr
Late D
O–S

The blue graph shows the apparent percentage (not the absolute number) of marine animal genera becoming extinct during any given time interval. It does not represent all marine species, just those that are readily fossilized. The labels of the

Cooksonia, the earliest vascular plant, middle Silurian

Silurian sea bed fossils collected from Wren's Nest Nature Reserve, Dudley UK

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years. The base of the Silurian is set at a major extinction event when 60% of marine species were wiped out. See Ordovician-Silurian extinction events.

单词	Lower Silurian
释义	Lower Silurian 英语例句库 Kapeng syderolite deposit is large,occurred in purple clayey ferruginous mudstone and grey-green clayey shale of Lower Silurian series. 卡棚大型紫砂陶土矿主要赋存于志留系下统紫红色粘土质含铁泥岩和灰绿色粘土质页岩中,分上下2个含矿岩系,4个矿层。 Based on the study of the Silurian sections in the Kalpin area of the northwestern Tarim Basin, eight ichnogenus and eight ichnospecies were recognized in the Lower Silurian Tataaiertage Formation. 通过对塔里木盆地柯坪地区志留系塔塔埃尔塔格组上段遗迹化石的研究,识别出8属8种。英语百科 Silurian The Silurian is a geologic period and system that extends from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years. The base of the Silurian is set at a major extinction event when 60% of marine species were wiped out. See Ordovician-Silurian extinction events.
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Lower Silurian

Silurian