Ordovician Period

485 million to 443 Million Years Ago

Exploring the Mysteries of the Ordovician Period: A Glimpse into Earth’s Ancient History


The Earth’s history is an intricate tapestry woven with countless chapters, each revealing unique and fascinating insights into the planet’s past. Among these captivating eras, the Ordovician Period stands as a remarkable chapter, spanning from approximately 485 million to 443 million years ago. Named after the Celtic tribe of the Ordovices, this period witnessed a plethora of transformative events, shaping the planet and paving the way for future life forms. Join us as we delve into the depths of the Ordovician Period, uncovering its geological marvels, extraordinary life forms, and its lasting impact on Earth’s evolutionary journey.

A Dynamic Earth:

During the Ordovician Period, the Earth underwent significant changes, both above and below the surface. Continents continued to drift, forming the supercontinent Gondwana in the southern hemisphere and Laurentia in the north. Shallow seas expanded across vast areas, creating favorable conditions for the flourishing of diverse marine life. Meanwhile, volcanic activity shaped the planet’s landscape, spewing out vast amounts of lava and enriching the oceans with minerals and nutrients.

Life in the Seas:

The seas of the Ordovician were teeming with an astonishing variety of marine life. The period witnessed the rise of arthropods, including trilobites, which were among the most successful and diverse creatures of the time. Brachiopods, mollusks, and early corals thrived in the warm and shallow marine environments. The oceans were also home to some of the earliest jawed fishes, such as the heavily armored placoderms. These remarkable creatures laid the groundwork for the future development of more advanced vertebrate life.

The Great Ordovician Biodiversification Event:

One of the most significant events of the Ordovician Period was the Great Ordovician Biodiversification Event (GOBE). Lasting approximately 25 million years, this event saw a remarkable explosion of biodiversity in marine ecosystems. A multitude of new species emerged, occupying a wide range of ecological niches. The GOBE transformed the marine fauna, leading to the rapid evolution of many new groups of organisms.

Climate and Environment:

The climate of the Ordovician was characterized by relatively stable and warm conditions, with no polar ice caps. A global greenhouse effect prevailed, resulting in higher sea levels and creating extensive shallow seas across the planet. These shallow seas hosted diverse ecosystems, and the presence of nutrient-rich waters fueled the proliferation of life forms.

Mass Extinctions and the Ordovician-Silurian Transition:

While the Ordovician Period was marked by the proliferation of life, it also witnessed significant mass extinctions that had a lasting impact on the planet’s biodiversity. Towards the end of the period, the Ordovician-Silurian Transition, two major extinction events occurred, collectively known as the Late Ordovician Extinctions. These events affected various marine species, including trilobites, brachiopods, and graptolites. The causes of these extinctions remain debated, but factors such as changes in sea level, climate fluctuations, and volcanic activity have been proposed as potential drivers.

Legacy and Significance:

The Ordovician Period laid the foundation for the subsequent evolution of life on Earth. The diverse marine ecosystems and the emergence of new groups of organisms during this period set the stage for the future dominance of fish and the eventual colonization of land. The impact of the Great Ordovician Biodiversification Event still reverberates in the biodiversity we observe today.


The Ordovician Period remains an enigmatic chapter in Earth’s history, offering a window into a world vastly different from our own. The period’s dynamic geological changes, explosive diversification of marine life, and the subsequent mass extinctions all shaped the evolutionary trajectory of life on our planet. By understanding and appreciating the wonders of the Ordovician Period, we gain a deeper appreciation for the vastness of Earth’s history and the remarkable journey of life that has brought us to the present day.