Terroir

• On the MapSwitch on the Terroir layer and see the rock under every appellation.
• Every appellation39 appellations, each with its soil, its height and a measured section.
• Side by sidePick any 2 and see their soil at one scale.
• 6 real boreholesReal cores from the BRGM notices, lined up from north to south.
• Saint-Émilion and PauillacA written walk across 2 soils: a limestone plateau and a gravel croupe.
• The Sky Over the VinesPick a day since 1842 and see the Bordeaux sky that day, wherever Météo-France holds the record.

People picture hills. Here is a croupe near Pauillac, measured every 5 meters by IGN. At 1×, you see it as it is: the land rises 17 m over 550 m, a slope of about 3%. The sections on this site stretch heights 20 times so the eye can read them. Slide, and watch the hills appear.

The jalles and the esteys cut the gravel into croupes in the ice ages, in the words of the Médoc AOC text. People finished the work on the palus. By his edict of 1599 on the drying of marshes, Henri IV handed the task to Humphrey Bradley, an engineer from Brabant, and his partners; one of them, Conrad Gaussen, signed for the marshes of Guyenne from 1599. Dutch names fill the list of those who backed the draining of the Lesparre marshes.

INAO, cahier des charges Médoc; de Dienne, Histoire du desséchement des lacs et marais en France avant 1789, 1891; Malvezin, Histoire du commerce de Bordeaux, volume II, 1892.

Pour 50 million years into a barrique of 225 liters, from the bottom up. Each liter holds about 222,000 years. Drag the level, or tap the barrel, and see what soil was being laid down at that liter.

Liter 72 to 102 of 225

33.9 to 27.3 million years ago: Rupelian, Oligocene

On the map of the appellations: Starfish limestone and marine marls.

Ages: the ICS International Chronostratigraphic Chart, v2024/12. Families: the ages BRGM’s harmonized map (BD Charm-50) prints for the soil inside the appellations, matched to the ICS stages. The old Alpine names (Günz, Mindel, Riss, Würm) and the northern European stages the notices use have no ICS numbers; all fall within the Pleistocene. Slope wash and cover carry no printed age and are left out.

On the Pomerol plateau, in places, the gravel thins and, at about 50 cm on average, gives way to a heavy, blue-gray clay. It breathes with the seasons.

This is the plateau, in places. Across most of Pomerol the gravel lies at the surface or just below. And the age of that clay is argued: Oligocene for the geologists of the Libourne map, of the ice ages for a university study, of open origin for 2 soil studies. And the “crasse de fer”?

Under the vines, the soil holds water. In winter the rain fills it and the water table rises; through spring and summer the vines drink, the sun dries the soil, and it sinks. 2 wells inside the delimited vineyard have been read for decades: one in the gravel at Macau, one in the starfish limestone at Le Taillan-Médoc. Turn the year.

In the Médoc gravel, Gérard Seguin found in 1975 that until early August the fine roots grow down into the soil the sinking water table leaves behind, and drink the water it leaves there. In that gravel, roots reach as far as 5 m, often stopped by the water table itself.

Where the water stays high, it sets a floor: in a sandy soil of the Isle valley, a 1978 study measured the water table between 50 cm below the surface in winter and 2 m in summer. It limits how deep the roots go and likely helps feed the vine.

Hub’Eau, ADES piezometry: wells BSS001XWGD (Macau, works 4.9 m deep) and BSS001XZUD (Le Taillan-Médoc, works 12.1 m deep). Monthly means of measures qualified as correct and read in the field only; for each month, the median over all years and the band where 8 years in 10 fall. Depth below the well’s reference mark. Roots drawn schematically. Seguin, Alimentation en eau de la vigne et composition chimique des moûts dans les grands crus du Médoc, 1975; Guilloux-Benatier, Duteau, Seguin, Connaissance de la Vigne et du Vin 12(3), 1978.

Every hard word arrives in 3 rungs: the plain word, the local word, the science word. Climb only as far as you like.

• gravel

  graves

  River terraces laid from the end of the Pliocene through the Pleistocene; the Pleistocene runs from 2.58 million to 11,700 years ago (ICS)

  Pebbles, stones and sand that the Garonne, the Dordogne and the Isle left behind in the ice ages. The word names a soil first and a wine district second.

  Sources: INAO, cahier des charges Graves; INAO, cahier des charges Margaux; Jullien, Topographie de tous les vignobles connus, 1816

• a low gravel rise

  croupe

  A remnant of a river terrace, left standing between valleys cut in the cold periods of the Pleistocene

  The long, rounded backs of gravel between the streams of the Médoc. The Médoc cahier also gives the local word “cos”. Measured near Pauillac, one rises 17 m over 550 m.

  Sources: INAO, cahier des charges Médoc; BRGM, notice Lesparre-Médoc, 1973; IGN RGE ALTI 5 m, line T1

• a stream

  jalle

  A small stream that drains the gravel toward the estuary

  The Médoc's word for its streams. The jalles and the esteys cut the gravel into croupes, in the words of the AOC text.

  Sources: INAO, cahier des charges Saint-Estèphe; Féret, Statistique générale de la Gironde, 1874

• a tidal creek

  estey

  A small tributary of the Garonne or the Dordogne that rises and falls with the tides of the estuary

  A Gascon word. Its water runs both ways, with the tide that comes up the estuary twice a day.

  Sources: Lavaud, La flotte communale au service de l'effort de guerre, 2013

• a drainage ditch

  craste

  A man-made ditch that carries water off flat, wet land

  Dug to dry the landes. A traveler in 1812 already heard the word “in the language of the country”.

  Sources: BRGM, notice Saint-Vivien-de-Médoc, 1972; Saint-Amans, Voyage agricole, botanique et pittoresque, 1812

• river marsh land

  palus

  Clayey alluvium of the Holocene, laid down as the sea rose after the last ice age (the Flandrian rise), from 11,700 years ago (ICS)

  The youngest soil along the rivers: rich, heavy, often gray or bluish clay. The BRGM glossary calls it marsh land; people drained it into fields.

  Sources: BRGM, notice Lesparre-Médoc, 1973; BRGM, notice Podensac, 1996; INAO, cahier des charges Bordeaux

• starfish limestone

  calcaire à astéries

  Marine limestone of the Rupelian, Oligocene, 33.9 to 27.3 million years ago (ICS)

  Named by Delbos in 1847 for the starfish bones packed inside it. It caps the plateau of Saint-Émilion, 10 to 15 m thick, and old underground quarries in it gave the stone that built the town.

  Sources: BRGM, notice Langon, 1978; BRGM, notice Libourne, 1995; BRGM, notice Blaye, 1977

• the same starfish limestone, by its older name

  calcaire de Bourg

  Rupelian, Oligocene, 33.9 to 27.3 million years ago (ICS)

  The Blayais name for the rock, until a commission reporting on the cuttings of the Bordeaux to Paris railway named it calcaire à astéries in 1847.

  Sources: BRGM, notice Blaye, 1977; Des Moulins and others, Rapport de la Commission, 1847

• old river and lake clays and sands

  molasse du Fronsadais

  Continental deposits from the late Eocene (Priabonian, from 37.71 million years ago) to the base of the Oligocene (from 33.9, ICS)

  Soft beds laid by rivers and lakes on land, under the starfish limestone. BRGM calls it a local term “hallowed by use”. Some modern writers call it a soft limestone; the geologists' maps describe clays and sands.

  Sources: BRGM, notice Lesparre-Médoc, 1973; Gourdon-Platel, Caractères physiques des terroirs du vignoble libournais, 1978

• lake limestone and clay

  calcaire de Castillon

  Lake deposits at the base of the Rupelian, Oligocene, from 33.9 million years ago (ICS)

  Green to whitish clays and limestones, 10 to 12 m thick, left by a lake. Matheron gave the name in 1867.

  Sources: BRGM, notice Libourne, 1995; BRGM, notice Blaye, 1977

• an older sea limestone

  calcaire de Saint-Estèphe

  Marine limestone of the late Eocene, Priabonian, 37.71 to 33.9 million years ago (ICS)

  A limestone from a sea older than the starfish one. Across the estuary, on the Montendre sheet, it shows as a hard, yellowish limestone in beds 10 to 40 cm thick.

  Sources: BRGM, notice Lesparre-Médoc, 1973; BRGM, notice Montendre, 1970

• shell sand

  falun

  A sea deposit packed with shells and shell fragments, in sand or marl; its age depends on the formation. In the Gironde the notices print faluns of the Oligocene and of the early Miocene (Aquitanian and Burdigalian, 23.04 to 15.98 million years ago, ICS)

  When the sea came back early in the Miocene it left beds of broken shells, often green from grains of glauconite. The 1973 notice, written before today's chart, put the start at about 25 million years.

  Sources: BRGM, notice Lesparre-Médoc, 1973; Linder, Des dépôts lacustres du vallon de Saucats, 1869; BRGM, notice Libourne, 1995

• iron pan

  alios

  A hardened soil layer where humus or iron has gathered and cemented the sand

  A dark, sandstone-like crust under the landes and some gravels. The AOC text calls it sand bound by iron; the BRGM glossary, a hardened layer of humus or iron. Roots and water stop at it.

  Sources: BRGM, notice Saint-Vivien-de-Médoc, 1972; INAO, cahier des charges Graves; Linder, Étude sur les terrains de transport, 1866

• “iron dross”, a local name

  crasse de fer

  No single meaning: the sources give 3

  A word of the Libournais, and the sources do not agree on what it names.

  The sources disagree

  • The Pomerol AOC text: iron oxides in the subsoil.
  • Cocks and Féret, from 1868: a hard, iron-rich soil, also called mâchefer.
  • A 1997 soil survey of Pomerol: iron and manganese concretions in the deep sandy soils of the south and west.
  • The BRGM Libourne notice never uses the term.

  Sources: INAO, cahier des charges Pomerol; Cocks and Féret, Bordeaux et ses vins, 1868; Mérouge, Arrouays, Seguin, Journal International des Sciences de la Vigne et du Vin 31(4), 1997; BRGM, notice Libourne, 1995

• the Libournais name for iron pan

  mâchefer

  Banks of alios, in the soil sense

  In industry the word means clinker. In the soils of the Libournais, Féret wrote, it is what people call the alios banks. All 3 French passages found are his.

  Sources: Féret, Saint-Émilion et ses vins, 1908; Féret, Les vins de l'arrondissement de Libourne, 1897

• pale silty soil

  boulbène

  A pale, acid, silty soil; how it got there is argued

  Fine, ash-colored soil on the plateaus between the rivers.

  The sources disagree

  • The AOC Bordeaux and Entre-deux-Mers texts: silts brought by the wind.
  • The BRGM Libourne notice: wind or floods, still disputed.
  • Franck, 1853: clay mixed with very fine rounded sand, without lime.
  • The English Cocks and Féret calls it soft in 1883 and hard in 1899.

  Sources: INAO, cahier des charges Entre-deux-Mers; BRGM, notice Podensac, 1996; BRGM, notice Libourne, 1995; Franck, Traité sur les vins du Médoc, 1853

• heavy clay soil

  terrefort

  Deep brown soils, clayey or clayey-sandy, formed on molasses and marls

  Strong soil, hard to work. BRGM calls these soils calcareous or calcic; the Saint-Macaire AOC text calls them decarbonated but calcic.

  Sources: BRGM, notice Sainte-Foy-la-Grande, 1994; INAO, cahier des charges Côtes de Bordeaux-Saint-Macaire; Cocks, Bordeaux, ses environs et ses vins, 1850

• gravelly red clay

  argile à graviers

  A very high river sheet of sand and gravel in a reddened clay; its age is argued

  It sits on the hilltops of the Entre-deux-Mers, a few meters to 15 m thick. The BRGM Bordeaux notice of 1977 calls it Pliocene; the Pessac notice of 1978 moves it to the base of the Pleistocene.

  Sources: BRGM, notice Libourne, 1995; BRGM, notice Pessac, 1978; BRGM, notice Bordeaux, 1977

• Landes sand

  sables des Landes

  Wind-blown sand of the Quaternary; the BRGM notices date it to the Late Glacial

  White to reddish quartz sand that the wind spread west of the croupes and between them. Writers of the 1860s to 1880s thought it Tertiary or Pliocene; the BRGM notices place it at the end of the last ice age.

  Sources: BRGM, notice Pessac, 1978; INAO, cahier des charges Saint-Estèphe; Linder, Étude sur les terrains de transport, 1866

• swelling clay

  smectite

  A family of clay minerals that take in water and swell

  In some Libournais deposits it makes up 60 to 70% of the clay. It holds a great deal of water, yet a 2008 study found that little of it is available to the vine.

  Sources: BRGM, notice Libourne, 1995; INAO, cahier des charges Pomerol; van Leeuwen and others, Alimentation hydrique de la vigne et qualité des raisins, 2008

• river terrace

  terrasse

  A step of old river deposits left high as the river cut down

  Stairs of gravel along the rivers, the oldest highest. At Margaux they now stand as hills between 6 and 33 m.

  Sources: Linder, Étude sur les terrains de transport, 1866; INAO, cahier des charges Margaux

• hillside

  coteau

  A slope cut into Tertiary rock, below a plateau

  On the Côtes de Bordeaux the steep face drops about 30 m in some places and more than 70 m in others, with a plateau on top and the river plain below.

  Sources: INAO, cahier des charges Côtes de Bordeaux; Franck, Traité sur les vins du Médoc, 1853

• table land

  plateau

  At Saint-Émilion, the flat top of the starfish limestone, up to 100 m

  Rivers ate into its edge and left steep combes, where the villages shelter. The Dordogne lies to the south, the Barbanne to the north.

  Sources: INAO, cahier des charges Saint-Émilion; Roudié, 1968

• river-rolled pebbles

  cailloux roulés

  Pebbles rounded by transport in water, mostly quartz

  Pieces of the Pyrenees carried down the Garonne, and of the Massif Central down the Dordogne and the Isle, worn smooth on the way.

  Sources: Billaudel, Essai sur le gisement des cailloux roulés, 1830; Des Moulins, Étude sur les cailloux roulés de la Dordogne, 1866

• marl

  marne

  A rock of clay and lime mixed together

  Féret put the mix at about half clay, half lime, and noted that it crumbles in damp air.

  Sources: Féret, Statistique générale de la Gironde, 1878

• heath

  lande

  Flat, sandy, poorly drained land under heather and pine

  Wet in winter and burnt in summer, as an old text put it. West of the croupes the vines give way to it.

  Sources: Franck, Traité sur les vins du Médoc, 1853; Joubert and others, Culture de la vigne dans le Médoc, 1842

These words are also in the Study cards.

• Barsac
• Blaye Côtes de Bordeaux
• Bordeaux AOC
• Bordeaux Supérieur
• Cadillac Côtes de Bordeaux
• Canon-Fronsac
• Castillon Côtes de Bordeaux
• Cérons
• Côtes de Bordeaux
• Côtes de Bordeaux-Saint-Macaire
• Côtes de Bourg
• Crémant de Bordeaux
• Entre-deux-Mers
• Francs Côtes de Bordeaux
• Fronsac
• Graves
• Graves de Vayres
• Graves Supérieures
• Haut-Benauge
• Haut-Médoc
• Lalande-de-Pomerol
• Listrac-Médoc
• Loupiac
• Lussac-Saint-Émilion
• Margaux
• Médoc
• Montagne-Saint-Émilion
• Moulis
• Pauillac
• Pessac-Léognan
• Pomerol
• Premières Côtes de Bordeaux
• Puisseguin-Saint-Émilion
• Saint-Émilion
• Saint-Estèphe
• Saint-Georges-Saint-Émilion
• Saint-Julien
• Sainte-Croix-du-Mont
• Sauternes

• BRGM, harmonized geological map of the Gironde at 1:50,000 (BD Charm-50) and the sheet notices (Licence Ouverte 2.0)
• IGN, RGE ALTI 5 m, Gironde, edition 2021-04-19 (Licence Ouverte)
• INAO, digitized parcel delimitation of 2026-10-12; the AOC cahiers des charges
• International Commission on Stratigraphy, International Chronostratigraphic Chart v2024/12
• Mérouge, Arrouays, Seguin, Journal International des Sciences de la Vigne et du Vin 31(4), 1997; Mérouge, Seguin, Arrouays, same journal 32(2), 1998
• Van Leeuwen, Baudet, Duteau, Seguin, Wilbert, Connaissance de la Vigne et du Vin 23(3), 1989