The Cambrian is a geologic period of the Paleozoic Era, spanning approximately 539–485 million years ago, characterized by a major diversification of multicellular life known as the Cambrian explosion. It follows the Ediacaran Period and precedes the Ordovician. Stratigraphically, its base is defined by the first appearance datum of complex trace fossils such as Treptichnus pedum, and it is subdivided into series and stages based on biostratigraphic markers, particularly trilobites and small shelly fossils. The Cambrian is critical for calibrating early Phanerozoic evolutionary, paleoenvironmental, and tectonic reconstructions.
The oldest fossilized remains of complex animals appear suddenly in the fossil record, and as if from nowhere, in rocks that are 538 million years old.
Paleontology & Fossils
Jan 6, 2026
0
80
Skeleton season may be just around the corner, but the skeleton age dawned with the early Cambrian Period, about 538 million to 506 million years ago.
Evolution
Oct 15, 2025
0
135
The explosion of animal life in Earth's oceans half a billion years ago during and after the Cambrian Period is commonly attributed to a substantial and sustained rise of free oxygen (O2) in seawater. Some researchers even ...
Earth Sciences
Sep 4, 2025
0
30
The Burgess Shale in British Columbia is renowned for its exceptional preservation of soft tissues in fossils, including limbs and guts. While trilobites are abundant in the fossil record thanks to their hard exoskeleton, ...
Paleontology & Fossils
Aug 4, 2025
0
329
A treasure trove of exceptionally preserved early animals from more than half a billion years ago has been discovered in the Grand Canyon, one of the natural world's most iconic sites.
Evolution
Jul 23, 2025
0
229
The Cambrian Explosion is a landmark moment in the history of life on Earth when many of the major groups of animals first appear in the fossil record.
Paleontology & Fossils
Jul 10, 2025
0
402
The Cambrian explosion was an extraordinary phenomenon in the evolution of life on the planet that led to the emergence of many animal phyla and the diversification of species. During this period, some 530 million years ago, ...
Evolution
Jun 26, 2025
0
173
In a first-of-its-kind study, Stanford researchers have measured how the abundance of ocean life has changed over the past half-billion years of Earth's history.
Earth Sciences
Jun 25, 2025
0
62
