English: Fat-Mats (from Leyel, 1722 & Wiman, 1941)

---

This is the story of Fat-Mats. It in no way counts as a story about fossils, but it does give some interesting insights into how organic remains can be preserved for long periods of time.

Matthias Israelsson was a 17th century miner who worked at the Martin Fur Copper Mine in Falun, Sweden. In 1670, a small mine collapse killed and buried him. In the 1680s, the entire underground mine complex collapsed, leaving a large depression at the land surface. Several decades later, in 1719, the mine was drained of its standing water and a human body was found under collapsed rocks. The body had been very well preserved while submerged in mine waters, despite the passage of almost 50 years. Observers remarked that the man merely looked asleep. His clothes identified him as a miner. The preserved body was put on display, and many curious onlookers came to view it. One old woman who saw the corpse fell down with a cry of exclamation. She recognized the body as Mats Israelsson, her former fiancé. He still looked young, and she was now an old woman. Other older visitors also recognized Mats.

Investigations into how the body of Mats had become preserved showed that “vitriolic waters” (= dilute sulfuric acid) were responsible. “Vitriol” refers to sulfate salts. “Fresh” from the mine waters, Mats’ body was still soft and pliable. The body had swollen somewhat, leading to the nickname "Fat-Mats". When it dried out, the flesh and skin became hard as stone. People remarked that the body had no stench of decay.

The great Carl Linnaeus was among those who saw the body on display in a glass case at the copper mine museum in Falun. He concluded that Fat-Mats was not completely petrified, just coated with sulfate salts (= the mineral chalcanthite - CuSO4·5H2O, hydrous copper sulfate). He predicted that the sulfate would eventually completely disappear on contact with air moisture, and the body would subsequently start decomposing. This is exactly what happened. By the late 1730s, the body had blackened, dessicated, and become disfigured. It also emitted the stench of decay. On 21 December 1749, Mats Israelsson was coffined.

In the early 1800s, a chemical analysis on deep mine waters at Falun showed the following:

Water - 91.4% Sulfuric acid - 4.393% Iron oxide - 1.320% Magnesium oxide - 0.600% Zinc oxide - 0.550% Aluminum oxide - 0.350% Manganese oxide - 0.271% Copper oxide - 0.060% Calcium oxide - trace

---

• • • Note - his headstone states the year of death as 1677. The original literature (see Leyel, 1722) states repeatedly that Mats died in 1670 and that his body had been underground for 49 years.

---

Synthesized from:

Leyel, A. 1722. Narratio accurata de cadavere humano in fodina cuprimontana ante duos annos reperto. Acta Literaria Sveciæ 1: 250-254. [in Latin]

Wiman, C. 1941. Über neue und einige alte Leichenwachsfunde. Bulletin of the Geological Institution of the University of Upsala 28: 141-155. [in German]