RESEARCH BASE

Search 3,721 documents across 34 fields — every claim tier-rated by evidence

3,721 Documents 34 Sections 43,625 Citations 34,852 Keywords Indexed 4 Evidence Tiers

3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.

4 results for "Ordovician"

E_5_02 Verified Cataclysms & Chronology

E_5_02 — The Ordovician-Silurian Mass Extinction

The Late Ordovician mass extinction (c. 445–444 million years ago, at the Ordovician-Silurian boundary) was the second-most severe extinction event in Earth's history in terms of percentage of species lost — approximatel

Ordovician Silurian mass extinction Hirnantian glaciation Late Ordovician graptolites
O_2_06 Verified Earth Anomalies

O_2_06 — Richat Structure — Saharan Eye and Atlantis Claims

The Richat Structure (also called the Eye of the Sahara or Guelb er Richat) is a prominent circular geological formation approximately 40–50 km in diameter located on the Adrar Plateau in west-central Mauritania (21°07′N

Richat Structure Eye of the Sahara Guelb er Richat Mauritania dome geological formation
R_1_11 Verified Biology & Evolution

R_1_11 — Extinction, Recovery, and Adaptive Radiation

The history of life is punctuated by mass extinction events — catastrophic biodiversity losses that eliminate >75% of species in geologically brief intervals — followed by recovery phases and adaptive radiations during w

mass extinction Big Five adaptive radiation recovery background extinction end-Permian
R_1_03 Verified Biology & Evolution

R_1_03 — Mass Extinction Events

Life on Earth has endured at least five catastrophic mass extinctions in 540 million years, each eliminating 60–96% of all species. The "Big Five" are: End-Ordovician (~443 Mya, ~85% species lost), Late Devonian (~372 My

mass extinction Big Five Permian Cretaceous K-Pg Chicxulub