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| Matuyama Chron | |
|---|---|
| Name | Matuyama Chron |
| Start | ~2.58 Ma |
| End | ~0.78 Ma |
| Period | Pleistocene |
| Named for | Motonori Matuyama |
| Notable for | Reversed geomagnetic polarity interval |
Matuyama Chron The Matuyama Chron is a major interval of reversed geomagnetic polarity during the late Pliocene and early Pleistocene epochs, notable for encompassing multiple polarity events and geomagnetic excursions. It provides a primary magnetostratigraphic framework used across paleomagnetism, stratigraphy, and Quaternary research, linking marine and terrestrial sequences from the Pacific Ocean to the Mediterranean Sea.
The Matuyama Chron spans much of the Pleistocene and parts of the Pliocene, bounded above by the transition to the Brunhes Chron and below by the Gauss Chron. It is central to magnetostratigraphic correlation in studies of the Laetoli hominin sites, Olduvai Gorge, Dmanisi, and other fossil-bearing localities. The chron underpins age models used in investigations at the Vostok Station ice cores, EPICA cores, and multiple Ocean Drilling Program sites, and has featured in syntheses by the International Union for Quaternary Research and the International Chronostratigraphic Chart.
During the Matuyama Chron the Earth's geomagnetic field exhibited predominantly reversed polarity relative to the present Brunhes Chron, with notable features such as the Brunhes–Matuyama reversal and a series of short-lived normal-polarity subchrons, including the Jaramillo Subchron and the Olduvai Subchron. Geomagnetic intensity variations and secular variation during this interval are recorded in basalt flows from the Hawaii and Iceland volcanic provinces, in paleomagnetic studies of loess deposits in China and Europe, and in magnetization of marine sediments from the North Atlantic, South Atlantic, Indian Ocean, and Southern Ocean.
Chronological placement of the Matuyama Chron relies on integration of magnetostratigraphy with radiometric dating techniques such as argon–argon dating, uranium–lead dating, and astrochronology aligned to orbital parameters described by Milankovitch. The Matuyama is subdivided by subchrons and excursions recognizable in sequences from the Mediterranean Sea sapropels, Loess Plateau loess-paleosol sequences, Chesapeake Bay cores, and the Tortonian through Calabrian stages in regional stratigraphic charts. Key stratigraphic markers include the Brunhes–Matuyama boundary, Jaramillo and Olduvai subchrons, and geomagnetic excursions correlated with marine isotope stages established in deep-sea benthic foraminifera records.
Evidence for the Matuyama Chron arises from paleomagnetic measurements of remanent magnetization in igneous rocks, sediments, and archaeological materials, analyzed using alternating-field and thermal demagnetization, and vector component analysis developed in laboratories at institutions such as Lamont–Doherty Earth Observatory, Scripps Institution of Oceanography, and the Geological Survey of Japan. Age control is achieved by coupling paleomagnetic polarity stratigraphy with 40Ar/39Ar dating of tephra layers from volcanic centers like Mount Etna, Kilauea, and Campi Flegrei, and by correlation with oxygen isotope stratigraphy from cores recovered during Integrated Ocean Drilling Program expeditions and by varve counting in lacustrine archives like Lake Baikal.
Regional records of the Matuyama Chron are documented in the Loess Plateau of China, the Thar Desert-adjacent sequences, the Mediterranean Basin marine terraces, Andean uplift-related deposits, and in volcanic sequences across the Iberian Peninsula, Japan, and New Zealand. Correlations use tie-points from magnetostratigraphic logs at Site 926 and Site 983 from the Ocean Drilling Program, the Blake Nose records, and continental sites including Hernando River exposures and Olduvai Gorge beds. These tie-ins link paleomagnetic polarity to biostratigraphic markers such as foraminifera turnovers, pollen assemblages, and vertebrate faunal stages like the Villafranchian.
The Matuyama Chron coincides with major climatic fluctuations recorded in marine isotope stages, ice-core records from Greenland and Antarctica, and glacial sequences across North America and Eurasia. Its timing intersects with tectonic and paleoenvironmental events influencing hominin dispersal at Dmanisi, faunal migrations across the Bering Land Bridge, and volcanism affecting Mediterranean sapropel formation. The reversed polarity interval is used to date sedimentary deposits critical to reconstructing Pleistocene glacial–interglacial cycles described in frameworks developed by researchers at Cambridge University, University of California, Berkeley, and the Max Planck Institute for Evolutionary Anthropology.
The chron is named after the Japanese geophysicist Motonori Matuyama, whose work on geomagnetism built on earlier contributions by Bernhard Brunhes, Gustav Adolf Sauerbeck, and researchers at the United States Geological Survey. Subsequent refinement came from paleomagnetic pioneers including Keith Runcorn, Aubertin, Allan Cox, Richard Doell, and interdisciplinary programs such as the Deep Sea Drilling Project, Ocean Drilling Program, and International Marine Global Change Study. Modern high-resolution studies integrate techniques advanced at Scripps Institution of Oceanography, ETH Zurich, Columbia University, and national geological surveys to resolve subchron boundaries and excursions within the Matuyama interval.
Category:Geomagnetism Category:Pleistocene