The Late Ordovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician-Silurian extinction, is the first of the "big five" major mass extinction events in Earth's history, occurring roughly 445 million years ago (Ma). [1]

The Late Ordovician is the third and final epoch of the Ordovician period, lasting 15.1 million years and spanning from around 458.2 to 443.1 million years ago. [4] [5] The rocks associated with this epoch are referred to as the Upper Ordovician Series.

2023年12月18日 · The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle.

2020年5月18日 · The Ordovician saw major diversification in marine life abruptly terminated by the Late Ordovician mass extinction (LOME). Around 85% of species were eliminated in two pulses 1 m.y. apart. The first pulse, in the basal Hirnantian, has been linked to cooling and Gondwanan glaciation.

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle.

The Late Ordovician mass extinction, which reduced species diversity more than 50%, has been linked to the expansion of Gondwanan ice sheets, global cooling and the restriction of climatic belts, a prominent eustatic sea level fall and subsequent rise, and changes in oceanic upwelling, nutrient abundance, and water chemistry.

In the late Lower Ordovician, the diversity of conodonts decreased in the North Atlantic Realm, but new lineages appeared in other regions. Seven major conodont lineages went extinct, but were replaced by nine new lineages that resulted from a major evolutionary radiation. These lineages included many new and morphologically different taxa.

2021年12月2日 · Increased volcanism-related phosphorus delivery to the Late Ordovician ocean helps explain widespread cooling and eutrophication-driven extinctions, as shown by a biogeochemical model ...

Late Ordovician refers to a specific time period between 458 to 423 million years ago, characterized by a transition from a greenhouse to an icehouse world and a significant mass extinction event where around 85% of marine species went extinct. You might find these chapters and articles relevant to this topic. Philip D. Mannion, ...

The Late Ordovician refers to a period characterized by significant abiotic changes in the Earth system, including lower temperatures, cyclical sea level changes, oceanic ventilation, higher atmospheric oxygen levels, and fully circulating oceans.