Huronian
Encyclopedia
The Huronian glaciation extended from 2400 Mya to 2100 Mya, during the Siderian
and Rhyacian periods of the Paleoproterozoic
era, triggered by the oxygen catastrophe
, which oxidised the atmospheric methane
(a greenhouse gas
). It was one of the most severe and longest ice age
s in geologic history, similar to the Snowball Earth
ice ages that happened in the Neoproterozoic
era. It was named due to evidence collected from Lake Huron
region in North America
where three separate horizons of glacial deposits are separated by non-glacial sediment
.
The cause of the Huronian glaciation is not settled:
Siderian
The Siderian is the first geologic period in the Paleoproterozoic Era and lasted from 2500 Mya to 2300 Mya . Instead of being based on stratigraphy, these dates are defined chronometrically....
and Rhyacian periods of the Paleoproterozoic
Paleoproterozoic
The Paleoproterozoic is the first of the three sub-divisions of the Proterozoic occurring between . This is when the continents first stabilized...
era, triggered by the oxygen catastrophe
Great Oxygenation Event
The Great Oxygenation Event , also called the Oxygen Catastrophe or Oxygen Crisis or Great Oxidation, was the biologically induced appearance of free oxygen in Earth's atmosphere. This major environmental change happened around 2.4 billion years ago.Photosynthesis was producing oxygen both before...
, which oxidised the atmospheric methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
(a greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
). It was one of the most severe and longest ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
s in geologic history, similar to the Snowball Earth
Snowball Earth
The Snowball Earth hypothesis posits that the Earth's surface became entirely or nearly entirely frozen at least once, some time earlier than 650 Ma . Proponents of the hypothesis argue that it best explains sedimentary deposits generally regarded as of glacial origin at tropical...
ice ages that happened in the Neoproterozoic
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1,000 to 542.0 ± 1.0 million years ago. The terminal Era of the formal Proterozoic Eon , it is further subdivided into the Tonian, Cryogenian, and Ediacaran Periods...
era. It was named due to evidence collected from Lake Huron
Lake Huron
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
region in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
where three separate horizons of glacial deposits are separated by non-glacial sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
.
The cause of the Huronian glaciation is not settled:
- perhaps triggered by the oxygen catastropheOxygen CatastropheThe Great Oxygenation Event , also called the Oxygen Catastrophe or Oxygen Crisis or Great Oxidation, was the biologically induced appearance of free oxygen in Earth's atmosphere. This major environmental change happened around 2.4 billion years ago.Photosynthesis was producing oxygen both before...
; - perhaps by a 250 million year lull in volcanic activity, resulting in lesser carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
levels and a reduced green house effect; - perhaps due to the tilting of the EarthEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
at the time. 2.5 billion years ago, the Earth had a much larger tilt than today. Earth is currently tilted on its axis at about 23.5 degrees.