Walther Penck (30 August 1888 – 29 September 1923) was a

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, alth ...

and

geomorphologist 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 ...

known for his theories on landscape evolution. Penck is noted for criticizing key elements of the Davisian

cycle of erosion The geographic cycle, or cycle of erosion, is an idealized model that explains the development of relief in landscapes. The model starts with the erosion that follows uplift of land above a base level and ends, if conditions allow, in the format ...

, concluding that the process of uplift and denudation occur simultaneously, at gradual and continuous rates. Penck's idea of parallel slope retreat led to revisions of Davis's cycle of erosion.

Biography

Walther Penck was born in Vienna as the son of German geographer

Albrecht Penck Albrecht Penck (25 September 1858 – 7 March 1945) was a German geographer and geologist and the father of Walther Penck. Biography Born in Reudnitz near Leipzig, Penck became a university professor in Vienna, Austria, from 1885 to 1906, a ...

.Encyclopædia Britannica 2014 He obtained a PhD by studying

petrology Petrology () is the branch of geology that studies rock (geology), rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly ...

at the Heidelberg University. Between 1912 and 1915 he worked in Dirección General de Minas in

Buenos Aires Buenos Aires ( or ; ), officially the Autonomous City of Buenos Aires ( es, link=no, Ciudad Autónoma de Buenos Aires), is the capital and primate city of Argentina. The city is located on the western shore of the Río de la Plata, on South Am ...

before moving to the University of Constantinople where he was named professor of mineralogy and geology. He finally settled as professor in the University of Leipzig in 1918. The areas he studied in detail and based his theories on include the

Black Forest The Black Forest (german: Schwarzwald ) is a large forested mountain range in the States of Germany, state of Baden-Württemberg in southwest Germany, bounded by the Rhine Valley to the west and south and close to the borders with France and S ...

in Germany,

Puna de Atacama The Puna de Atacama or Atacama Plateau''Atacama Plateau''
article at the ''

Anatolia in modern Turkey. During the 1920s Penck, with Siegfried Passarge,

Alfred Hettner Alfred Hettner (August 6, 1859 in Dresden – August 31, 1941 in Heidelberg) was a German geographer. He is known for his concept of chorology, the study of places and regions, a concept that influenced both Carl O. Sauer and Richard Hartshor ...

and his father, was the foremost figure in a broad German opposition to the "geographical cycle" theory of William Morris Davis. It was characteristic of Davis to react violently and disdainfully to criticism, particularly to this German criticism; it was also his characteristic to choose to attack the most vulnerable points of that criticism. Regarding Walther Penck's objections to the Davisian geographic cycle Davis commented to Albrecht Penck in 1921:

It is pleasant news that your son, Walther, is established as professor in Leipzig where his father long ago studied. As he may have told you, I have enjoyed reading parts of his Argentine monograph, an able piece of work, and I have written asking him to specify the difficulties he finds in accepting the cycle theory. I am inclined to believe that he really does not know what that theory is...

Walther Penck died of

oral cancer Oral cancer, also known as mouth cancer, is cancer of the lining of the lips, mouth, or upper throat. In the mouth, it most commonly starts as a painless white patch, that thickens, develops red patches, an ulcer, and continues to grow. When on ...

in September 1923. His book, ''Morphological Analysis of Landforms'', was published posthumously in 1924 by his father as was also his paper (The piedmont-flats of the southern Black Forest).Simons 1962

Geomorphological theory

Concepts

In his analysis Penck utilized the following concepts: #: A low-angle landscape with concave slopes. It is the final stage of erosion that follows after inselbergs and pediments are eroded. #: A series of folds and synclines analogous to orogenic folding. It is usual type of folds created by lateral compression in the crust. As the develops it narrows at the same time they become higher.Beckinsale & Chorley 2003, p. 340 Can be translated as 'great fold' in English. Davis translated it into 'broad fold'. Penck himself was unhappy with the term . #: Can be translated into English as 'piedmont flat', 'piedmont bench' or 'piedmont step'.Sube 2001, p. 1019 #''

Piedmonttreppen A piedmonttreppen or piedmont benchland is a conceived landform consisting in a succession of benches at different heights and that forms in sequence during the uplift of a geological dome. The concept was first proposed in a posthumous publicatio ...

'': descending erosional benches on an uplifted area. Their shape is more or less concentric. Penck interpreted the as the result of doming. Benches he thought originated as in the periphery of the dome before they were uplifted. It can be translated into English as 'piedmont benchland', 'piedmont stairway' or 'piedmont treppe'. #: A more or less plain and subtly convex slope. The form is given by the very slow waxing of erosion. Erosion cycles should begin from a . Can be formed at the base of a dome. #

Landform and landscape evolution according to uplift rate

Walther Penck thought landform development depended on uplift rate. He saw three main types of landform and landscape development all of which begun with or and ended with . The differences between them depended on their rate of uplift: peneplains developed in places with a low rate of uplift, intermediate forms developed in places of moderate uplift, and Alpine forms developed on places of rapid uplift.Chorley ''et al''. 2005, p. 619 In Penck's valley development model the steepness of valley slopes depended on the rate of uplift; this view contrasts with the Davis's erosion cycle, in which valley slope steepness depends on its relative age or stage of development.Chorley ''et al''. 2005, p. 629

Landform associations

Penck thought earths surface could be divided into three types of regions each with an own landform association. First there were regions of and general doming, then there were regions of pure doming, and at last there were regions of stability.

Criticism and legacy

William Morris Davis, a friend of Penck's father, criticized the theories Walther Penck outlined in . Geographer Martin Simons claimed in 1962 that Davis misunderstood and mis-translated parts of the paper leaving a distorted view of Penck's ideas among later workers. Simons therefore does not consider Davis an adequate critic of Penck's work. Other factors detrimental to an understanding of Penck's ideas include his early death and his confusing writing style. Albrecht Penck did is not known to have publicly taken any stance for or against his son's theory. Douglas Wilson Johnson, a coastal geomorphologist and staunch supporter of Davis, criticized Penck's theory harshly as: :"Penck’s conception that slope profiles are convex, plane, or concave according to the circumstances of the uplifting action, sone of the most fantastic errors ever introduced into geomorphology" Penck's theories had a much more limited influence in Germany compared to the English-speaking world where they gained notoriety for their contrasts to Davis'. As of 1983 it was noted that albeit Penck's theories were ignored in the discussion of the geomorphology of Central European massifs, the theories were often discussed in English-language Geomorphological textbooks.

Julius Büdel Julius Büdel (8 August 1903 – 28 August 1983) was a German geomorphologist noted for his work on the influence of climate in shaping landscapes and landforms. In his work Büdel stressed the importance of inherited landforms in present-day ...

, a German geomorphologist working in the same areas as Penck in Southern Germany, provided alternative explanations in 1935 for some of the landforms Penck had dealt with.Mensching 1984 Geographer Allaoua Saadi remarks by 2013 that Penck's and Davis' ideas have become more compatible and even complementary since the advent of modern tectonic theory. This author claims that Davis' ideas are more applicable near

active margin Active may refer to: Music * ''Active'' (album), a 1992 album by Casiopea * Active Records, a record label Ships * ''Active'' (ship), several commercial ships by that name * HMS ''Active'', the name of various ships of the British Roya ...

s where tectonics are "cataclysmic" and Penck's ideas fit better in

passive margin A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting crea ...

s and continental platforms.Saadi 2013 Walther Penck has a volcano named after him in northwestern Argentina.

Citations

References

* * * * * * * * * {{DEFAULTSORT:Penck, Walther 1888 births 1923 deaths 20th-century German geologists German geographers German geomorphologists Petrologists Servicio Geológico Minero personnel 20th-century geographers Scientists from Vienna Austro-Hungarian emigrants to Germany Expatriates from the Austro-Hungarian Empire in the Ottoman Empire Expatriates from the Austro-Hungarian Empire in Argentina