Lossen, Karl August

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Lossen, Karl August

(b. Kreuznach, Germany, 5 January 1841; d. Berlin, Germany, 24 February 1893)

geology, petrology.

Lessen was the son of a doctor and his wife Charlotte Mayer. He was educated at the high school and Gymnasium in Kreuznach. He married his cousin Therese Lossen and had two daughters and one son. Lossen began work as a mining engineer in the siderile deposits of the siegerland in Westphalia and in the coal mines of Saarbrücken. He broadened his studies in geology, mineralogy, and microscopic petrography, which was then just developing, under the guidance of Beyrich, Girard, Rammelsberg, G. Rose, and J. Roth. In 1866, after graduating from the University of Halle, he was introduced by Dechen at the Geological Survey of Prussia, and started working under the direction of Hauchecorne and Beyrich.

Lossen’s main work was the mapping and description of the very complicated geology of the Harz Mountains, which were then still rather unknown, but which have since, because of Lossen’s work, become one of the classic regions for geological study. He worked there part of every year from 1866 to 1892 and completed a geological map of the area in the scale of 1 : 100,000, and, incidentally, maps of smaller areas in the scale of 1 :25,000 as by-products. He produced significant papers on the Devonian period, especially the Lower Devonian, and the early Carboniferous period in that region, which had previously been mistaken for Silurian.

Lossen also did essential work in microscopical petrology, and with this, along with geological observations in the field, became one of the first to report the influence of tectonic movements on metamorphism (dynamometamorphism).

By 1866 Lossen could show that gneissic and phyllitic rocks of the Hunsrük Mountains were Lower Devonian sediments. He discovered similar things in the Ostharz, where he also observed transitions between contact metamorphic and dynamometamorphtc rocks. For metamorphic tuffs he coined the name “porphyroid.”

In 1870 Lossen became a lecturer at the University of Berlin. He was appointed an associate professor in 1882 and full professor of petrology in 1886. While in Berlin, he redefined the old name “Hcayman,” which he then used only for the lower part of the Lower Devonian.

Many of Lossen’s works concern the magmatic rocks of the Saar-Nahe basin. From these were drawn numerous definitions, in part now completely misused, especially of rocks of the melaphyreporphyrite-tholeite family.


A list of Lossen’s publications may be found in the obituary by E. Kayser in Neues Jahrbuch fur Mineralogies Geologie und Paläontologie,2 (1893), App. 1-18.

P. Ramdohr