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    Marl

    Half clay, half limestone: the rock of Barolo and Chablis.

    Marl in the atlas

    1. Atlas regionBordeaux
    2. Atlas regionSancerre
    3. Atlas regionChablis
    4. Atlas regionChampagne
    5. Atlas regionCôte de Nuits
    6. Atlas regionMosel
    7. Atlas regionAlsace
    8. Atlas regionBarolo

    Atlas regions where this rock appears in the text or the soil profile.

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    What it is

    Marl is a mixture of clay and calcium carbonate, between a clayey limestone and a calcareous clay.1 The Chablis appellation rules describe its local marls, the Marnes à Exogyra virgula, as compact, impermeable clayey limestones.2

    marl
    gravel
    clay

    Schematic: how fast water drains through the rock. A qualitative comparison based on the sources on this page.

    On the slope

    In Chablis, scree covering the marl forms a layer that drains and warms well, and slopes are chosen for drainage and early warming of the soil.2

    Where to see it

    The Sant'Agata Fossili marls are the most widespread formation of Barolo.3 Marl is one of the three limestone rocks of Champagne.4 In Bordeaux, the gravel of Pauillac covers older marls and limestones.5

    Regions

    Sources

    1. Energy Glossary: marl. SLB (Schlumberger). level 5 · checked 2026-10-13
    2. Cahier des charges de l'AOC « Chablis » (décret n° 2011-1752 du 2 décembre 2011). INAO / Ministère de l'Agriculture, 2011. level 1 · checked 2026-10-13
    3. Climate and geology. Consorzio di Tutela Barolo Barbaresco Alba Langhe e Dogliani. level 4 · checked 2026-10-13
    4. Champagne and its soil. Comité Champagne. level 4 · checked 2026-10-13
    5. Cahier des charges de l'appellation d'origine contrôlée « Pauillac». INAO, 2025. level 1 · checked 2026-10-13