The Mesoproterozoic Era is a
geologic era
An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth.
Comp ...
that occurred from . The Mesoproterozoic was the first era of Earth's history for which a fairly definitive geological record survives. Continents existed during the preceding era (the
Paleoproterozoic
The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions ( eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...
), but little is known about them. The continental masses of the Mesoproterozoic were more or less the same ones that exist today, although their arrangement on the Earth's surface was different.
Major events and characteristics
The major events of this era are the breakup of the
Columbia supercontinent
Columbia may refer to:
* Columbia (personification), the historical female national personification of the United States, and a poetic name for America
Places North America Natural features
* Columbia Plateau, a geologic and geographic region in ...
, the formation of the
Rodinia supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...
,
and the evolution of
sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...
.
This era is marked by the further development of continental plates and
plate tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
. The supercontinent of Columbia broke up between 1500 and 1350 million years ago,
[ and the fragments reassembled into the supercontinent of Rodinia around 1100 to 900 million years ago, on the time boundary between the Mesoproterozoic and the subsequent Neoproterozoic.] These tectonic events were accompanied by numerous orogenies (episodes of mountain building
Mountain formation refers to the geological processes that underlie the formation of mountains. These processes are associated with large-scale movements of the Earth's crust (tectonic plates). Folding, faulting, volcanic activity, igneous int ...
) that included the Kibaran orogeny
The Kibaran orogeny is a term that has been used for a series of orogenic events, in what is now Africa, that began in the Mesoproterozoic, around 1400 Ma and continued until around 1000 Ma when the supercontinent Rodinia was assembled.
The term " ...
in Africa; the Late Ruker orogeny in Antarctica; the Gothian and Sveconorwegian orogenies in Europe; and the Picuris
Picuris Pueblo (; Tiwa: P'įwweltha ’ī̃wːēltʰà is a historic pueblo in Taos County, New Mexico, United States. It is also a census-designated place (CDP) and a federally recognized tribe of Native American Pueblo people. The 2010 censu ...
and Grenville orogenies in North America.
The era saw the development of sexual reproduction, which greatly increased the complexity of life to come and signified the start of development of true multicellular organisms
A multicellular organism is an organism that consists of more than one cell, in contrast to unicellular organism.
All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni ...
. Though the biota of the era was once thought to be exclusively microbial, recent finds have shown multicellular life did exist during the Mesoproterozoic. This era was also the high point of the stromatolites
Stromatolites () or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). Th ...
before they declined in the Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.
It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is ...
.
The era did see large quantities of organisms in at least some areas at some periods: The EIA/ARI ''Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside the United States'' of June 2013 estimated around of natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
in place (ca. recoverable) and around 93 billion barrels
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, u ...
of oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
in place (ca. 4.7 billion recoverable) in the Lower Kyalla and Middle Velkerri formations alone of the Beetaloo Basin in Australia's Northern Territory.[U. S. Energy Information Administration/Advanced Resources International, ''Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside of the United States'', June 2013, p. III-46. The Lower Kyalla and Middle Velkerri formations are identified as Mesoproterozoic in references, p. III-49.]
Subdivisions
The subdivisions of the Mesoproterozoic are arbitrary divisions based on time. They are not geostratigraphic or biostratigraphic units. The decision to base the Precambrian time scale on radiometric dating reflects the sparse nature of the fossil record, and Precambrian subdivisions of geologic time roughly reflect major tectonic cycles. It is possible that future revisions to the time scale will reflect more "natural" boundaries based on correlative geologic events.
The Mesoproterozoic is presently divided into the Calymmian
The Calymmian Period (from grc, κάλυμμα, kálymma, meaning "cover") is the first geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined ...
(1600 to 1400 Mya) and the Ectasian
The Ectasian Period (from grc, ἔκτασις, éktasis, meaning "extension") is the second geologic period in the Mesoproterozoic Era and lasted from Mya ago to Mya (million years ago). Instead of being based on stratigraphy, these dates ...
(1400 to 1200 Mya), and the Stenian
The Stenian Period (, from grc, στενός, stenós, meaning "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined ...
(1200 to 1000 Mya). The Calymmian and Ectasian were characterized by stabilization and expansion of cratonic covers and the Stenian by formation of orogenic belts.[
The time period from 1780 Ma to 850 Ma, an unofficial period based on ]stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks.
Stratigrap ...
rather than chronometry, named the Rodinian, is described in the geological timescale review 2012 edited by Gradstein et al., but , this has not yet been officially adopted by the International Union of Geological Sciences (IUGS).
See also
*Boring Billion
The Boring Billion, otherwise known as the Mid Proterozoic and Earth's Middle Ages, is the time period between 1.8 and 0.8 billion years ago (Ga) spanning the middle Proterozoic eon, characterized by more or less tectonic stability, climatic st ...
References
External links
Mesoproterozoic (chronostratigraphy scale)
{{Authority control
Geological eras