Hirnantian

Wangjiawan sectionMap of China showing the GSSP location.

Key events in the Ordovician

view • discuss •

-485 —

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-480 —

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-475 —

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-470 —

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-465 —

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-460 —

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-455 —

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-450 —

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-445 —

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P
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Cambrian

O
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Silurian

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L
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Tremadocian

Floian

Dapingian

Darriwilian

Sandbian

Katian

Hirnantian

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First land plant spores

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Ordovician meteor event

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Archaeocyatha extinction

Key events of the Ordovician Period.
ICS approved stages.

Axis scale: millions of years ago.

The Hirnantian is the seventh and final internationally recognized stage of the Ordovician Period of the Paleozoic Era. It was of short duration, lasting about 1.9 million years, from 445.2 ± 1.4 to 443.8 ± 1.5 Ma (million years ago). The early part of the Hirnantian was characterized by cold temperatures, major glaciation, and a severe drop in sea level. In the latter part of the Hirnantian, temperatures rose, the glaciers melted, and sea level returned to the same or to a slightly higher level than it had been prior to the glaciation.

单词	Hirnantian
释义	Hirnantian 英语百科 Hirnantian Key events in the Ordovician view • discuss • -485 — – -480 — – -475 — – -470 — – -465 — – -460 — – -455 — – -450 — – -445 — – P a l e o z o i c Cambrian O r d o v i c i a n Silurian E a r l y M i d d l e L a t e Tremadocian Floian Dapingian Darriwilian Sandbian Katian Hirnantian ← First land plant spores ← Ordovician meteor event ← Archaeocyatha extinction Key events of the Ordovician Period. ICS approved stages. Axis scale: millions of years ago. The Hirnantian is the seventh and final internationally recognized stage of the Ordovician Period of the Paleozoic Era. It was of short duration, lasting about 1.9 million years, from 445.2 ± 1.4 to 443.8 ± 1.5 Ma (million years ago). The early part of the Hirnantian was characterized by cold temperatures, major glaciation, and a severe drop in sea level. In the latter part of the Hirnantian, temperatures rose, the glaciers melted, and sea level returned to the same or to a slightly higher level than it had been prior to the glaciation.
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