What happened during the Proterozoic era?

During the Proterozoic Eon, modern plate tectonics became active, and the ancient cores of the continents moved over wide areas of the globe, accumulating smaller fragments of crust and sometimes colliding with other large landmasses. The opposite also happened, leading to continental rifting.

What lived during the Proterozoic era?

During the Proterozoic the atmosphere and oceans changed significantly. Proterozoic rocks contain many definite traces of primitive life-forms—the fossil remains of bacteria and blue-green algae as well as the first oxygen-dependent animals, the Ediacara fauna.

What are the major global events that occurred in the Proterozoic?

The well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes; several glaciations, which produced the hypothesized Snowball Earth during the Cryogenian Period in the late Neoproterozoic Era; and the Ediacaran Period (635 to 538.8 Ma) …

What major change occurred in life forms at the end of the Proterozoic?

With the beginning of the Mesoproterozoic comes the first evidence of oxygen build-up in the atmosphere. This global catastrophe spelled doom for many bacterial groups, but made possible the explosion of eukaryotic forms. These included multicellular algae, and toward the end of the Proterozoic, the first animals.

What was Earth like in the Proterozoic era?

During the Proterozoic, the earth had cooled considerably from the previous Hadean eon when the planet was covered by molten lava. Near the end of the Proterozoic, ice sheets were growing towards the equator, and the entire planet was possibly engulfed under a thin layer of snow and ice.

What important evolutionary step occurred in the Proterozoic?

Figure 8.5. 1: Modern cyanobacteria (as stromatolites) in Shark Bay, Australia. However, during the Proterozoic, a large evolutionary step occurred with the appearance of eukaryotes.

When did continental glaciation occur during the Proterozoic?

When did continental glaciation occur during the Proterozoic? The period of glaciation occurred sometime between 2.6 and 2.1 billion years ago.

What happened during Snowball Earth?

Snowball Earth hypothesis, in geology and climatology, an explanation first proposed by American geobiologist J.L. Kirschvink suggesting that Earth’s oceans and land surfaces were covered by ice from the poles to the Equator during at least two extreme cooling events between 2.4 billion and 580 million years ago.

What happened during the Cryogenian period?

The Cryogenian period (ca. 720–635 million years ago) was a period of dynamic environmental change that witnessed the low-latitude glaciation and super continental breakup of Rodina and associated rift-magmatic activity^1,2. The Sturtian glaciations (ca. 715–680 million years ago) and Marinoan glaciations (ca.

How did the atmosphere and tectonic conditions change during the Proterozoic eon?

How did the atmosphere and tectonic conditions change during the Proterozoic Eon? The atmosphere became oxygenated (and depleted of some carbon dioxide) as a result of photosynthesis.

What event in Earth’s history was responsible for the increase in atmospheric oxygen during the Proterozoic?

Cyanobacteria, photosynthetic organisms that produce oxygen as a byproduct, had first appeared 3.5 billion years ago, but became common and widespread in the Proterozoic. Their photosynthetic activity was primarily responsible for the rise in atmospheric oxygen.

Which supercontinent formed during the Proterozoic?

Gondwana (see GONDWANALAND AND GONDWANA) was a southern hemisphere supercontinent composed principally of South America, Africa, Arabia, Madagascar, India, Antarctica, and Australia. It formed in the latest Proterozoic and was largely completed by the Early Cambrian (750–550 Ma).