Jens Esmark (31 January 1763 – 26 January 1839) was a Danish-Norwegian professor of
mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...
who contributed to many of the initial discoveries and conceptual analyses of
glaciers
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
, specifically the concept that glaciers had covered larger areas in the past.
Biography
Jens Esmark was born in
Houlbjerg in
Århus
Aarhus (, , ; officially spelled Århus from 1948 until 1 January 2011) is the second-largest city in Denmark and the seat of Aarhus Municipality. It is located on the eastern shore of Jutland in the Kattegat sea and approximately northwest ...
,
Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Danish Realm, Kingdom of Denmark
...
. Esmark moved to Norway to the silver mining community of
Kongsberg
Kongsberg () is a historical mining town and municipality in Buskerud, Viken county, Norway. The city is located on the river Numedalslågen at the entrance to the valley of Numedal. Kongsberg has been a centre of silver mining, arms production ...
. He studied at the
local mining academy. He completed his subsequent studies in
Copenhagen
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
and was accepted as a
surveyor
Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...
. Starting in 1797, Esmark was employed as a lecturer in mineralogy at the Kongsberg Mining Academy. In 1814, Esmark became Norway's first professor of
geology
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...
as a professor of geology at the
University of Oslo
The University of Oslo ( no, Universitetet i Oslo; la, Universitas Osloensis) is a public research university located in Oslo, Norway. It is the highest ranked and oldest university in Norway. It is consistently ranked among the top universit ...
, and was described as "a pioneer in glacial geology", by professor of
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
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...
and
Glaciology
Glaciology (; ) is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice.
Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, climato ...
Bjørn G. Andersen
Bjørn Grothaug Andersen (23 March 1924 in Norway, 1924, in Stavanger, Norway – 12 January 2012 in Norway, 2012, in Asker, Norway) was a Norwegians, Norwegian professor of Quaternary geology and glaciology who made foundational contributio ...
.
In 1798, Esmark was the first person to ascend
Snøhetta
Snøhetta is the highest mountain in the Dovrefjell mountain range in Norway. At , it is the highest mountain in Norway outside the Jotunheimen range, making it the 24th highest peak in Norway, based on a topographic prominence cutoff. At , it ...
, highest in the mountain range
Dovrefjell
Dovrefjell is a mountain range in Central Norway that forms a natural barrier between Eastern Norway and Trøndelag. The mountain range is located in Innlandet, Møre og Romsdal, and Trøndelag counties in Norway. As a result of its central loca ...
in southern
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 ...
. The same year he led the first expedition to
Bitihorn
Bitihorn (local pronunciation: ) is a mountain on the border of Vang Municipality and Øystre Slidre Municipality in Innlandet county, Norway. The tall mountain is located in the Jotunheimen mountains about northwest of the village of Beitost ...
, a small mountain in the southernmost outskirts of
Jotunheimen
Jotunheimen (; "the home of the Jötunn") is a mountainous area of roughly in southern Norway and is part of the long range known as the Scandinavian Mountains. The 29 highest mountains in Norway are all located in the Jotunheimen mountains, in ...
, Norway. In 1810 he was the first person to ascend the mountain
Gaustatoppen
Gaustatoppen is the highest mountain in the county Vestfold og Telemark in Norway which lies in the municipality Tinn and Hjartdal. The view from the summit is impressive, as one can see an area of approximately 60,000 km², one sixth of Norw ...
in
Telemark
Telemark is a traditional region, a former county, and a current electoral district in southern Norway. In 2020, Telemark merged with the former county of Vestfold to form the county of Vestfold og Telemark. Telemark borders the traditional ...
, Norway.
Professor Esmark theorized in 1824 that glaciers had once been larger and thicker and had covered much of Norway and the adjacent
sea floor. He also attributed
erratic boulders and
moraines
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 she ...
to glacial transportation and deposition. He first recognized glaciers as a powerful agent of
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
that had carved the Norwegian
fjords
In physical geography, a fjord or fiord () is a long, narrow inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Alaska, Antarctica, British Columbia, Chile, Denmark, Germany, Greenland, the Faroe Islands, Icela ...
.
Professor Esmark was also an important figure in the history and cultural heritage of
mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...
. He introduced
norite
Norite is a mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite, orthopyroxene, and olivine. The name ''norite'' is derived from ''Norge'', the Norwegian name for Norway.
Norite also known as orthopyrox ...
the name for which was derived from the Norwegian name for Norway, ''Norge''.
On the island of
Løvøya, Norway, his son,
Hans Morten Thrane Esmark, found the first specimens of a black mineral,
thorite
Thorite, (Th,U)SiO4, is a rare nesosilicate of thorium that crystallizes in the tetragonal system and is isomorphous with zircon and hafnon. It is the most common mineral of thorium and is nearly always strongly radioactive. It was named in 1829 to ...
, from which the element
thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...
is derived. His son also provided him with a new mineral which he found in
Arendal
Arendal () is a List of municipalities of Norway, municipality in Agder counties of Norway, county in southeastern Norway. Arendal belongs to the Districts of Norway, region of Southern Norway, Sørlandet. The administrative centre of the munici ...
, Norway. In 1806 he named
datolite
Datolite is a calcium boron hydroxide nesosilicate, Ca B Si O4(O H). It was first observed by Jens Esmark in 1806, and named by him from δατεῖσθαι, "to divide," and λίθος, "stone," in allusion to the granular structure
of the massi ...
, from the Greek word meaning "to divide". This was a reference to the granular structure of the first specimens studied.
In 1825, Professor Esmark was elected a member of the
Royal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special ...
. In 1832, he was Knighted in the Swedish
Order of Vasa
The Royal Order of Vasa () is a Swedish order of chivalry, awarded to citizens of Sweden for service to state and society especially in the fields of agriculture, mining and commerce. It was instituted on 29 May 1772 by King Gustav III. It was u ...
.
Selected works
*''Kurze Beschreibung einer mineralogischen Reise durch Ungarn, Siebenbürgen und das Bannat'' ( Freyberg, 1798)
*''Reise fra Christiania til Trondhjem'' (1829)
Notes
References
*Cunningham, F.F. (1990) ''James David Forbes: Pioneer Scottish glaciologist'' (Edinburgh: Scottish Academic Press)
*Burroughs, William James (2005) ''Climate Change in Prehistory: The End of the Reign of Chaos'' (Cambridge University Press)
*Hestmark, Geir 2009. “Her ligger Sneen evig.” – Da Dovre falt – for Esmarks barometer. Historisk Tidsskrift 88: 231-249.
*Hestmark, Geir 2012. To discover, yes, but top publish...? Jens Esmark, datolite..and thulite. Norwegian Mining Museum, Publication No. 49: 45-52.
*Hestmark, G. 2018. Jens Esmark's mountain glacier traverse 1823 – the key to his discovery of ice ages. Boreas 47: 1-10. https://doi.org./10.1111/bor.12260. ISSN 0300-9483. Open access.
*Hestmark, G. 2017. Istidens Oppdager. Jens Esmark, pioneren i Norges fjellverden. En Biografi. Kagge Forlag AS, Oslo.720 s. .
External links
*
Forsand
{{DEFAULTSORT:Esmark, Jens
1763 births
1839 deaths
Norwegian glaciologists
Norwegian mountain climbers
Norwegian mineralogists
Members of the Royal Swedish Academy of Sciences
People from Aarhus
Knights of the Order of Vasa
Royal Norwegian Society of Sciences and Letters
18th-century Norwegian scientists
19th-century Norwegian scientists