Baron Gerard Jacob De Geer (20 November 1858 – 24 July 1943) was a
Swedish
Swedish or ' may refer to:
Anything from or related to Sweden, a country in Northern Europe. Or, specifically:
* Swedish language, a North Germanic language spoken primarily in Sweden and Finland
** Swedish alphabet, the official alphabet used by ...
geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...
who made significant contributions to
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
geology, particularly
geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
and
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...
. De Geer is best known for his work on
varve
A varve is an annual layer of sediment or sedimentary rock.
The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (var ...
s. In 1890 De Geer was the first to apply the name
Ancylus Lake
Ancylus Lake is a name given by geologists to a large freshwater lake that existed in northern Europe approximately from 9500 to 8000 years B.C being in effect one of various predecessors to the modern Baltic Sea.
Origin, evolution and demise
The ...
to the Baltic
paleolake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
discovered by
Henrik Munthe
Henrik Vilhelm Munthe (1 November 1860 – 15 August 1958) was a Swedish geologist.
Biography
Munthe became a student in 1882 and in 1892 a doctor of philosophy and associate professor of geology at Uppsala University, where he was acting profes ...
. He subsequently participated the protracted scientific controversy surrounding this lake.
Biography
Baron Gerard Jacob De Geer comes from a well-known
Swedish aristocratic family of
Brabant Brabant is a traditional geographical region (or regions) in the Low Countries of Europe. It may refer to:
Place names in Europe
* London-Brabant Massif, a geological structure stretching from England to northern Germany
Belgium
* Province of Bra ...
origin, who had emigrated to Sweden in the early seventeenth century. His family included prominent industrialists and politicians. His father
Louis Louis may refer to:
* Louis (coin)
* Louis (given name), origin and several individuals with this name
* Louis (surname)
* Louis (singer), Serbian singer
* HMS ''Louis'', two ships of the Royal Navy
See also
Derived or associated terms
* Lewis ( ...
and older brother
Gerhard Louis served as the
Prime Minister of Sweden
The prime minister ( sv, statsminister ; literally translating to "Minister of State") is the head of government of Sweden. The prime minister and their cabinet (the government) exercise executive authority in the Kingdom of Sweden and are subj ...
.
Gerard Jacob was born on October 2, 1858 in
Stockholm
Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...
in the family of Baron Louis Gerhard de Geer, at that time the
first Minister of Justice in the
Swedish government
The Government of the Kingdom of Sweden ( sv, Konungariket Sveriges regering) is the national cabinet of Sweden, and the country's executive authority.
The Government consists of the Prime Ministerappointed and dismissed by the Speaker of the R ...
, and Carolina de Geer, née Countess Wachtmeister. Since 1869 he studied at primary school, and since 1873 - at the
Stockholm gymnasium. In 1877, de Geer entered
Uppsala University
Uppsala University ( sv, Uppsala universitet) is a public university, public research university in Uppsala, Sweden. Founded in 1477, it is the List of universities in Sweden, oldest university in Sweden and the Nordic countries still in opera ...
. In May 1879 he graduated and received a
Bachelor of Arts
Bachelor of arts (BA or AB; from the Latin ', ', or ') is a bachelor's degree awarded for an undergraduate program in the arts, or, in some cases, other disciplines. A Bachelor of Arts degree course is generally completed in three or four years ...
degree.
In 1878, De Geer became an employee of the
Geological Survey of Sweden
Geological Survey of Sweden ( sv, Sveriges geologiska undersökning, SGU) is a Swedish government agency that was founded in 1858 dealing with questions about the nature of the geological and mineral management in Sweden. The institution has the ...
, initially freelance, then, since 1882, as an assistant to a geologist, and since 1885, a full-time geologist. At this time he started to study the late
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
deposits and landforms of southern Sweden. In 1897, he left his job in the geological service for the position of professor of general and historical geology at
Stockholm University
Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...
.
In 1882, on the recommendation of
Otto Martin Torell
Prof Otto Martin Torell HFRSE (5 June 1828 – 11 September 1900) was a Swedish naturalist and geologist.
Life
He was born in Varberg, Sweden on 5 June 1828 the son of Johan Petter Torell and his wife, Susanna Charlotta Varenius.
He was educa ...
, de Geer participated in the Swedish expedition to
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...
as part of the first International Polar Year as a staff geologist. This marks the beginning of many years of research on the modern glaciation of the Svalbard archipelago: in total he took part in six expeditions to Svalbard (1882, 1896, 1899, 1901, 1908 and 1910).
Gerard de Geer remained a lecturer at the Department of Geology at the University of Stockholm from 1897 to 1924. At the university, he served as rector (1902-1910) and vice-chancellor from (1911-1924). In addition, De Geer was a member of the
Swedish Parliament
The Riksdag (, ; also sv, riksdagen or ''Sveriges riksdag'' ) is the legislature and the supreme decision-making body of Sweden. Since 1971, the Riksdag has been a unicameral legislature with 349 members (), elected proportionally and s ...
from 1900 to 1905.
The pinnacle of de Geer's scientific career can be considered the receipt of the presidency of the X International Geological Congress, held in Stockholm in 1910. At first he took part in the preparation of the Congress as vice-chairman of the preparatory committee, and from May 1907 - as chairman of the executive committee. Within the framework of the congress, he delivered the now classic lecture "A geochronology of the last 12000 years".
[
] He began this lecture with such words "Geology is the history of the earth, but hitherto it has been a history without years." At the congress De Geer formally introduced the term
varve
A varve is an annual layer of sediment or sedimentary rock.
The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (var ...
defining it as any annual sedimentary layer, and also proposed that the term
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...
be restricted to varve dating, other existing techniques being less accurate and precise. By then, observations of 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: lithostrati ...
relationship between varved sediment and recessional
moraine
A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...
s, and the correlation of varve sequences between geographically distant sites, added more compelling evidence to De Geer's essentially circumstantial speculation. The geological community accepted that the couplets were unlikely to represent any period other than the year. In addition, before the start of the Congress, De Geer conducted an excursion for 65 delegates from 14 countries, within the framework of which he examined the
Dicksonfjorden
Dicksonfjorden is a fjord branch of Isfjorden at Spitsbergen, Svalbard. It is located between James I Land and Dickson Land, and is named after Swedish Baron Oscar Dickson
Baron Oscar Dickson, or Oskar Dickson (2 December 1823 – 6 June 18 ...
on Spitsbergen.
Main research areas
De Geer's early studies of
raised beach
A raised beach, coastal terrace,Pinter, N (2010): 'Coastal Terraces, Sealevel, and Active Tectonics' (educational exercise), from 2/04/2011/ref> or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin,P ...
es, used to reconstruct glacio-
isostatic sea level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
changes, and his mapping of glacial
moraine
A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...
s to reconstruct the extent of the last Scandinavian ice sheet and its pattern of deglaciation (the particular type of moraine he studied is now referred to as ''De Geer moraine''), were well received. However, De Geer is most famous for discovering
varve
A varve is an annual layer of sediment or sedimentary rock.
The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (var ...
s and pioneering their use in
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...
.
During fieldwork in 1878, De Geer noticed that the appearance of laminated sediments deposited in glacial lakes at the margin of the retreating Scandinavian
ice sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Las ...
at the end of the last
ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
, closely resembled
tree-rings. In his best known work ''Geochronologia Sueccia'', published in 1940, De Geer wrote "From the obvious similarity with the regular, annual rings of the trees I got at once the impression that both ought to be annual deposits" (1940, p. 13).
While this observation was not new, De Geer was the first geologist to exploit its potential application. De Geer called these annual sedimentary layers
varve
A varve is an annual layer of sediment or sedimentary rock.
The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (var ...
s and throughout the 1880s further developed his theory, publishing a brief outline of his discovery in 1882, which he followed with a presentation to the Swedish Geological Society in 1884. It was not until 1910, at the International Geological Congress, that De Geer's pioneering work reached the wider international scientific community.
The Swedish Time Scale
In 1897 De Geer was appointed professor of geology at
Stockholm University
Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...
, and went on to become the university's president from 1902 to 1910. With the help of numerous students from both Stockholm and Uppsala, De Geer began to piece together short, but overlapping, varve sequences in south east Sweden to create a longer year-by-year chronology of glacial retreat for the
Lateglacial period. The urban expansion of Stockholm provided perfect conditions for De Geer and his colleagues, who made good use of numerous exposures of laminated sediment in the many pits and cuttings that exposed the glacial lake sediments of the Baltic basin. Estuarine sediments exposed along the valley of the Angermanalven River, allowed De Geer to further extend the chronology into the early
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...
. The resulting varve chronology was called the Swedish Time Scale, and geologists outside Sweden soon followed suit using varved sediments to build high-resolution chronologies of glacial retreat, most notably Matti Sauramo in
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
.
Global expeditions, teleconnections, and controversy
De Geer firmly believed the main control on varve sedimentation was solar radiation acting on glacier meltwater production, and that consequently, varved sediments represented a "..gigantic, natural self-registering thermograph" (De Geer 1926) and varve curves (varve thickness plotted against varve number or year), which he often referred to as "solar curves", a reliable
proxy
Proxy may refer to:
* Proxy or agent (law), a substitute authorized to act for another entity or a document which authorizes the agent so to act
* Proxy (climate), a measured variable used to infer the value of a variable of interest in climate ...
for past changes in
solar radiation
Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument.
Solar irradiance is measured in watts per square metre (W/m ...
. Ultimately, De Geer hoped his studies of varves would explain the fundamental cause of Ice Ages - "If the last glaciation everywhere should show to be synchronous and the origin of the last Ice Age thus to be of a general nature, the assumption of a cosmic cause would scarcely be avoidable."
In 1915 De Geer matched, or 'teleconnected", varve curves from Sweden to varve curves from
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
and
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
. This first attempt at long-distance correlation marked the start of two decades travelling around the world by De Geer and his colleagues, searching out varve sequences for potential teleconnections. In 1920 De Geer travelled to
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
with his wife and two assistants,
Ernst Antevs
Ernst Valdemar Antevs (November 20, 1888 – May 19, 1974) was a Swedish-American geologist and educator who made significant contributions to Quaternary geology, particularly geomorphology and geochronology.
Ernst Valdemar Antevs was born o ...
and Ragnar Liden. Antevs remained in North America at the end of the trip, where he worked on the North American varve chronology. Further trips included Erik Norin's visit to the
Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...
(1924–1925), Erik Nilsson's visit to
East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the historical ...
(1927–28), and
Carl Caldenius
Carl Caldenius (1887–1961), until 1920 known by the surname Carlzon, was a Swedish Quaterany geologist and geotechnical engineer. He is mostly known for his geochronological work in Patagonia.
Caldenius worked as geotechnical engineer for the ...
' visit to
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
(1925–1929), and later to
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
(1932–34).
However, by the mid-1930s De Geer's teleconnections had become the subject of increasing criticism from his former student Ernst Antevs. Antevs correctly argued that the teleconnections were bad science, and that De Geer's Trans-Atlantic correlations were inaccurate. De Geer felt his position was being caricatured and intentionally misunderstood by Antevs, but did little scientifically to rebuff the criticisms levelled at him.
In 1924 De Geer retired from teaching and became the founder-director of the Geochronological Institute at
Stockholm University
Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...
.
Geochronologia Suecica Principles
In 1940, De Geer published his longest and best-known work ''Geochronologia Suecica Principles'', in which he presented part of the Swedish Time Scale in detail, and expounded upon his theories and work regarding varves.
Almost immediately after the publication of ''Geochronologia Suecica Principles'' De Geer's Swedish Time Scale underwent the first of many revisions, as other geologists became involved in the study of varves and more sites were examined.
However, international interest in varves diminished. The bitter dispute between De Geer and Antevs, coupled with the advent of new dating techniques, most importantly
radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The method was dev ...
, showed varves in a bad light.
De Geer died in Stockholm on July 24, 1943. His wife,
Ebba Hult De Geer, continued to publish his work, and add to it, into the 1950s.
Awards and recognition
De Geer's contributions to geology were recognised in the UK, where the
Geological Society
The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe with more than 12,000 Fellows.
Fe ...
awarded De Geer the
Wollaston Medal
The Wollaston Medal is a scientific award for geology, the highest award granted by the Geological Society of London.
The medal is named after William Hyde Wollaston, and was first awarded in 1831. It was originally made of gold (1831–1845), t ...
in 1920, and the
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
elected De Geer a foreign member in 1930. The ancient DeGeer Sea in modern-day Maritime Canada was named in his honour.
The
Swedish Antarctic Expedition
The Swedish Antarctic Expedition of 1901–1903 was a scientific expedition led by Otto Nordenskjöld and Carl Anton Larsen. It was the first Swedish endeavour to Antarctica in the Heroic Age of Antarctic Exploration.
Background
Otto Nordensk ...
(1901–1904) named a glacier on
South Georgia Island
South Georgia ( es, Isla San Pedro) is an island in the South Atlantic Ocean that is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. Stretching in the east†...
in the southern
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
after De Geer. The British would later rename the glacier
Harker Glacier
Harker Glacier is a tidewater glacier on South Georgia Island in the southern Atlantic Ocean. Harker glacier was first mapped by the Swedish Antarctic Expedition (1901-1904), and named De Geer Glacier, after Gerard De Geer (1858-1943), a Swedis ...
after a contemporary
English
English usually refers to:
* English language
* English people
English may also refer to:
Peoples, culture, and language
* ''English'', an adjective for something of, from, or related to England
** English national ide ...
geologist,
Alfred Harker
Alfred Harker FRS (19 February 1859 – 28 July 1939) was an English geologist who specialised in petrology and interpretive petrography. He was Lecturer in Petrology at the University of Cambridge for many years, and carried out field mapping ...
.
The valley of
De Geerdalen at
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...
,
Svalbard
Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
is named after him.
De Geer from a modern perspective
De Geer's most significant contribution to Quaternary science was unquestionably the identification of varves, and his recognition of their potential in establishing annual chronologies of past climatic and environmental change. The Swedish Time Scale was the most precise and accurate geological timescale of its day, and it is still being improved and added to today. His insistence that varves represented quantifiable proxies for past climate has since been borne out to a degree, but the relationship between varve thickness and hydrometeorological conditions is not as simple as he presumed. Varves have recently experienced a renaissance as methods and techniques of study have improved, and varves are now regularly used to calibrate radiocarbon timescales.
In many ways, De Geer's concerns mirror that of modern Quaternary geologists and
palaeoclimatologists, particularly his recognition of the need for high-resolution natural archives of past change, and the importance of testing whether global change is synchronous. De Geer's principle failing was his faith in teleconnections, where his findings were clearly influenced by his preconceptions. His belief that variations in solar radiation were the principal agent of all climate change has also since been shown to be incorrect. Nevertheless, De Geer asked all the right questions, and his errors can be attributed as much to over-enthusiasm and a single-minded passion, as they can to bad science.
Selected English language works
* De Geer, G. (1912), A geochronology of the last 12000 years. ''Congr. Géol. Int. Stockholm 1910, C.R.'', 241–253.
*
*
*
*
*
*
*
* De Geer, G. (1940), ''Geochronologia Suecia Principles'' .K.Svenska Vetenskapsakad. Handl.
References
Sources
* Spjeldnaes, N. (1972) pp. 329–330 in Gillispie, C. C. (Ed.) ''Dictionary of Scientific Biography'', American Council of Learned Societies, Charles's Scribner's Sons Publishers New York .
*
*
*
*
External links
Presentation Speech 1920 Nobel Prize in Chemistry
{{DEFAULTSORT:De Geer, Gerard
1858 births
1943 deaths
20th-century Swedish geologists
Quaternary geologists
Sedimentologists
Wollaston Medal winners
Scientists from Stockholm
Uppsala University alumni
Foreign Members of the Royal Society
Honorary Members of the Russian Academy of Sciences (1917–1925)
Swedish people of Dutch descent
19th-century Swedish geologists
Members of the Royal Society of Sciences in Uppsala