was a

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

geophysicist who was (in the late 1920s) the first to provide systematic evidence that the

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic ...

had been reversed in the early

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

and to suggest that long periods existed in the past in which the polarity was reversed. He remarked that the Earth's field had later changed to the present polarity. The era of reversed polarity preceding the current ''Brunhes Chron'' of normal polarity is now called the ''Matuyama Reversed Chron''; and the transition between them is called the ''Brunhes–Matuyama'' or ''Matuyama-Brunhes'' reversal.

Life

Matuyama Motonori was born at Uyeda (now Usa) in

Oita prefecture Oita often refers to: * Ōita Prefecture, Kyushu, Japan * Ōita (city), the capital of the prefecture Oita or Ōita may also refer to: Places * Ōita District, Ōita, a former district in Ōita Prefecture, Japan *Ōita Stadium, a multi-use stad ...

Japan on October 25, 1884, a son of a

Zen Zen ( zh, t=禪, p=Chán; ja, text= 禅, translit=zen; ko, text=선, translit=Seon; vi, text=Thiền) is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School (''Chánzong'' 禪宗), and ...

abbot Abbot is an ecclesiastical title given to the male head of a monastery in various Western religious traditions, including Christianity. The office may also be given as an honorary title to a clergyman who is not the head of a monastery. The ...

, Sumie (Sumiye) Tengai. His name was at first registered as Suehara Motonori after his mother’s family name, Suehara Kou, and was later changed to Sumie Motonori when his father became the chief priest at an eminent Zen Buddhist temple in Yamaguchi. In 1910 he was adopted by the Matsuyama (松山) family, when he married their daughter, Matsuyama Matsuye, and was known as Matsuyama Motonori. About 1926, in conformity with a then new convention of transliteration, he altered the

romanization Romanization or romanisation, in linguistics, is the conversion of text from a different writing system to the Roman (Latin) script, or a system for doing so. Methods of romanization include transliteration, for representing written text, a ...

of his adoptive family name to Matuyama. Matuyama was educated at the University of Hiroshima and

Kyoto Imperial University , mottoeng = Freedom of academic culture , established = , type = Public (National) , endowment = ¥ 316 billion (2.4 billion USD) , faculty = 3,480 (Teaching Staff) , administrative_staff = 3,978 (Total Staff) , students = ...

, where he was appointed to a lectureship in 1913. After spending the period 1919–21 at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...

working with Thomas C. Chamberlin studying ice, he returned to Japan and was made professor of theoretical geology at Kyoto Imperial University in 1922. He conducted a gravity survey of Japan during the period 1927–32, extending this to also cover

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

and

Manchuria Manchuria is an exonym (derived from the endo demonym " Manchu") for a historical and geographic region in Northeast Asia encompassing the entirety of present-day Northeast China (Inner Manchuria) and parts of the Russian Far East (Outer M ...

, and studied marine gravity using the Vening–Meinesz pendulum apparatus in a submarine. While rocks had earlier been found with polarities opposite to the present

field Field may refer to: Expanses of open ground * Field (agriculture), an area of land used for agricultural purposes * Airfield, an aerodrome that lacks the infrastructure of an airport * Battlefield * Lawn, an area of mowed grass * Meadow, a grass ...

and the hypothesis advanced that the field had reversed in the past, Matuyama was the first to conduct a disciplined study of the hypothesis. In 1926 he began collecting basalt specimens in Manchuria and Japan, and in 1929 published a paper showing that there was a clear correlation between the polarity and the

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

position. He remarked that the Earth's field had been reversed in the early

age and older, and that it had later changed to the present polarity. This reversed polarity, particularly as shown by the rocks of the

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

, provided crucial evidence for the

sea floor spreading Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener an ...

hypothesis of Harry H. Hess. Matuyama served the Kyoto Imperial University as dean of the Faculty of Science from June 1936 until December 1937; he retired from teaching in 1944 and was made professor emeritus in 1946. In May 1949, Matuyama was appointed the founding president of

Yamaguchi University is a national university in Yamaguchi Prefecture, Japan. It has campuses at the cities of Yamaguchi and Ube. History The root of the university was , a private school founded by Ueda Hōyō (, 1769–1853) in 1815. In 1863 the school became a ...

(N.B. the University transliterated his family name as Matsuyama). In 1950 he was elected a fellow of the

Japan Academy The Japan Academy ( Japanese: 日本学士院, ''Nihon Gakushiin'') is an honorary organisation and science academy founded in 1879 to bring together leading Japanese scholars with distinguished records of scientific achievements. The Academy is ...

Legacy

The transition, about 0.78 Ma, to ''normal'' polarity (i.e., that of the present Earth's field) is the ''Brunhes-Matuyama'' or ''Matuyama-Brunhes'' reversal. At the 1973 Burg Wartenstein Symposium, it was recommended that “The beginning of the Middle Pleistocene should be so defined as to either coincide with or be closely linked to the boundary between the Matuyama Reversed Epoch and the Brunhes Normal Epoch of paleomagnetic chronology”. This was finalized in 2020, when the Executive Committee of the International Union of Geological Sciences officially ratified the

Global Boundary Stratotype Section and Point A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted b ...

(GSSP) defining the base of the

Chibanian The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. T ...

Stage and Middle Pleistocene Subseries at the Chiba section, Japan, using the ''Matuyama-Brunhes reversal'' as a marker. The boundary, about 2.58 Ma, between the ''Gauss Normal Chron'' and the ''Matuyama Reversed Chron'' is known as the '' Gauss-Matuyama reversal''. Matsuyama Rocks, in

Crystal Sound Crystal Sound () is a sound in Antarctica between the southern part of the Biscoe Islands and the coast of Graham Land, with northern limit Cape Evensen to Cape Leblond and southern limit Holdfast Point, Roux Island, Liard Island and the Si ...

, Antarctica, are named in his honour and his work on ice crystals.

Life

Legacy

References

Further reading