# Extraction of clayey rocks A thematic map of the Atlas of Switzerland, the national atlas published by ETH Zurich. The map is drawn in the browser; this file describes it and lists its variants and links, but not the data values shown on the map. - Map: https://atlasderschweiz.ch/en/theme/extraction-of-clayey-rocks/ - Map id: 193 - Categories: Nature and Environment › Geology and raw materials › Mineral raw materials - Keywords: Geology, Rocks - Published: 2010-11-26 - Last revised: 2024-03-12 - Content language: English - Other languages: [Deutsch](https://atlasderschweiz.ch/de/thema/abbau-von-tongesteinen.md), [Français](https://atlasderschweiz.ch/fr/theme/exploitation-de-roches-argileuses.md), [Italiano](https://atlasderschweiz.ch/it/tema/estrazione-di-rocce-argillose.md) ## Description Clay is principally used in Switzerland as raw material for bricks. Clays are fine-grained products of weathering of other types of rock. Basically, a difference is made between transported sediments and «in situ», i.e. in place, products of weathering. Raw material properties and the formation of the deposits are influenced by the origin of the materials and the transport mechanisms, by the sedimentation environment as well as by chemical transformations and the degree of solidification. Switzerland is a country rich in raw materials for the production of bricks. In addition to archaeological artefacts, this is evidenced by numerous prehistoric pits for clay extraction and historical localities. At the beginning of the 20th century, over 300 small brickyards were supplied in raw materials by as many clay pits. The majority of the pits were in the Plateau region, the Jura and in the peripheral areas, while only a few deposits were found in the Pre-Alps and in the large Alpine valleys and in the canton of Ticino (Pliocene marl and Pleistocene loam). Small production centres, as well as the first mechanised brickyards, mainly used the many available deposits of more or less strongly decalcified, plastic surface clay. The limited availability of these materials and the tendency in this century to replace old brickyards with bigger, more efficient plants forced the industry to find new sources of raw materials. Thus an increased amount of solid rock, such as marl or clay schists were used, which represent at present four fifths of the annual extracted volume. The remaining 34 brickyards still in service until the end of 2000 covered their needs for raw materials from 58 pits. *Raw material reserves * The annual amount of extracted material from the clay pits varies between 100 and 100,000 cubic metres, with a mean value of about 25,000 cubic metres. In the year 1991, a total of approximately 1.4 million cubic metres of brick raw material was extracted. The assured raw material reserves are about 35 million cubic metres of material (solid volume), which will suffice to cover Swiss needs completely for approximately 35-40 years. In addition, about 70 million cubic metres of estimated reserves exist in the vicinity of currently used pits. Thus, Switzerland still has an enormous raw material potential, especially in molassic marl and opalinus clay. ## Sources - SGTK, Schweizerische Geotechnische Kommission (ed.) (1997): Die mineralischen Rohstoffe der Schweiz. Zürich: Schweizerische Geotechnische Kommission ## Data sources - SGTK, Schweizerische Geotechnische Kommission (2015): [Rohstoffinventar der Schweiz](http://www.sgtk.ch/) ## Data owners - [Swiss Geotechnical Commission, ETH Zurich (SGC)](http://www.sgtk.ch/) ## Citation The terms of use ask to name the Atlas of Switzerland and the data owners, and to keep the source references in exports, screenshots and embeds. Cite the map as: > Atlas of Switzerland (2024): Extraction of clayey rocks. ETH Zürich. Map data © SGC. https://atlasderschweiz.ch/en/theme/extraction-of-clayey-rocks/ ## Variants The map has 5 variants. Levels: time. The `u` value of a variant selects it in the links below. - 1907: `u=AC4AAAAA` - 1935: `u=AC0AAAAA` - 1965: `u=ACwAAAAA` - 1995: `u=ABUAAAAA` - 2015: `u=AmAAAAAA` (default) ## Links Replace `{u}` with the `u` value of a variant above, or leave out `u={u}` for the default variant. The map opens at its full extent; a link cannot set the map position. - Map: https://atlasderschweiz.ch/en/theme/extraction-of-clayey-rocks/?u={u} - Short link, stays valid when the title changes: https://atlasderschweiz.ch/en/t/193/?u={u} - Side by side with another map: https://atlasderschweiz.ch/en/comparison/?lt=193&lu={u}&rt={id of the other map}&ru={u of the other map, or leave out} Embed in another website (allowed by the terms of use, as long as the source references stay visible): ```html ``` In the embed URL, `dm` sets what is shown: `e` the map with its title bar (default), `p` also the values of an object clicked on the map, `m` only the map with a button that opens it in the atlas. `ig=1` (default) lets the map react to scrolling and dragging only after a click into it, `ig=0` right away. The size can be changed in `style`. ## Maps to compare with - [Chronostratigraphy: age of rocks](https://atlasderschweiz.ch/en/theme/chronostratigraphy-age-of-rocks.md) (id 164) For the use and citation of maps and data, see the [terms of use](https://atlasderschweiz.ch/en/terms-of-use/).