The Tabataud Quarry, situated in the northwestern French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 Massif Central

Massif Central

The Massif Central is an elevated region in south-central France, consisting of mountains and plateaux....

, is a very interesting site for mineral

Mineral

A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

s. The quarry

Quarry

A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

 used to be mined for its granodiorite

Granodiorite

Granodiorite is an intrusive igneous rock similar to granite, but containing more plagioclase than orthoclase-type feldspar. Officially, it is defined as a phaneritic igneous rock with greater than 20% quartz by volume where at least 65% of the feldspar is plagioclase. It usually contains abundant...

..

Geography

The Tabataud Quarry (sometimes also written Tabateaud) was excavated along the left bank of the river Bandiat

Bandiat

The Bandiat is a small river that is 91 km long, a left tributary of the Tardoire. It flows through the Haute-Vienne, Dordogne and Charente departments in France.-Geography:...

 at an elevation of 165 meters, only about one kilometer southeast of Nontron

Nontron

Nontron is a commune in the Dordogne department in Aquitaine in southwestern France.-History:According to the historian Ribault de Laugardière, the name Nontron derives from the Tyrian language, from Nata and Dun...

 town center. Nearby passes the D 707 from Nontron to Saint-Pardoux-la-Rivière

Saint-Pardoux-la-Rivière

Saint-Pardoux-la-Rivière , in occitan Sent Pardol la Ribiera, is a commune in the Dordogne department in Aquitaine in southwestern France. It forms part of the Parc naturel régional Périgord Limousin.- Etymology :...

, from which it is easily accessible. In the immediate vicinity are two more adjoining quarries, the Maspeyrot-Lagarde quarry and the Moulin Blanc quarry, which are both older. All these quarries are closed by now and they are dangerous due to rockfall.

Geology

The Tabataud quarry and its two satellites were worked from the Piégut-Pluviers Granodiorite

Piégut-Pluviers Granodiorite

The Piégut-Pluviers Granodiorite is situated at the northwestern edge of the Variscan Massif Central in France. Its cooling age has been determined as 325 ± 14 million years BP .- Geographical situation :...

, more precisely from its dark, fine-grained, biotite

Biotite

Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula . More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous endmembers...

- and amphibole

Amphibole

Amphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.-Mineralogy:...

-bearing (green hornblende

Hornblende

Hornblende is a complex inosilicate series of minerals .It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole....

) border facies. Because of its slight blueish hue the rock used to be called granite bleu (blue granite) by the local population. Along the west side of the quarry crosses a NNE-SSW-striking fault zone that sets off the granodiorite from the plagioclase

Plagioclase

Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...

-bearing paragneisses farther west. Within the quarry the granodiorite is traversed by a stockwork of mineralized dikes

Dike (geology)

A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...

. Altogether 17 southeast-northwest-striking lode

Lode

In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fissure in a rock formation or a vein of ore that is deposited or embedded between layers of rock....

s are encountered. They only reach thicknesses of about 3 centimeters, an exception being the Puyssechet lode near the Moulin Blanc quarry, which is 30 centimeters thick and strikes east-west. Besides the lodes there are also some pegmatite

Pegmatite

A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....

 dikes.

Mineralogy

The encountered lodes in the quarry belong to the classical sphalerite

Sphalerite

Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...

-pyrite

Pyrite

The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

-galena

Galena

Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

-chalcopyrite

Chalcopyrite

Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...

 ore

Ore

An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....

 mineral association. Like in the nearby Cantonnier Lode

Cantonnier Lode

The Cantonnier lode formed in the Piégut-Pluviers Granodiorite, part of the basement rocks of the northwestern French Massif Central. Its importance is highlighted by very rare mineral parageneses.- Geography :...

 the mineralizations formed hydrothermally

Hydrothermal circulation

Hydrothermal circulation in its most general sense is the circulation of hot water; 'hydros' in the Greek meaning water and 'thermos' meaning heat. Hydrothermal circulation occurs most often in the vicinity of sources of heat within the Earth's crust...

 in a medium temperature

Temperature

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 range of 300 to 150°C. But unlike in the Cantonnier lode the veins in the Tabataud quarry clearly focus on the primary mineral galena and not on its secondary minerals.

Matrix minerals in the lode are quartz

Quartz

Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

 and/or baryte. Common minerals are calcite

Calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

 and dolomite

Dolomite

Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

. Secondary minerals consist of lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 minerals like anglesite

Anglesite

Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and celestine. It contains 74% of lead by mass and...

, cerussite

Cerussite

Cerussite is a mineral consisting of lead carbonate , and an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name cruse to the mineral, whilst the present form, cerussite, is due to...

, pyromorphite

Pyromorphite

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb53Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal...

 and wulfenite

Wulfenite

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".It crystallizes...

, and of iron sulfide

Iron sulfide

Iron sulfide or Iron sulphide refers to a chemical compound of iron and sulfur with a wide range of stoechiometric formulae and different crystalline structures.-Natural minerals:By increasing order of stability:...

s like marcasite

Marcasite

The mineral marcasite, sometimes called white iron pyrite, is iron sulfide with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both structures do have in common that they contain the disulfide...

 and pyrite. A rarity is the bitumen containing pseudomineral ozocerite.

In the pegmatite veins one finds well developed garnet

Garnet

The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...

s (grain size 2 millimeters), millimetric tourmaline

Tourmaline

Tourmaline is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gem comes in a wide variety of colors...

 (schorl) and asparagus-coloured apatite

Apatite

Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...

 reaching 5 millimeters in size.

Attached a detailed description of the lode minerals:

• anglesite (PbSO₄): rare; millimetric, colourless prism
  Prism (geometry)
  In geometry, a prism is a polyhedron with an n-sided polygonal base, a translated copy , and n other faces joining corresponding sides of the two bases. All cross-sections parallel to the base faces are the same. Prisms are named for their base, so a prism with a pentagonal base is called a...
  
  s.
• baryte (BaSO₄): common in matrix; leafy habit, white coatings, spherical nodules, occurs together with galena (and marcasite).
• calcite (CaCO₃): late stage mineral in tension gashes; associated with galena; pointed (reflecting) and flattened (dull) rhombohedra; milky singular crystals can reach 5.5 centimeters.
• cerussite (PbCO₃): local concentrations; crystallizes on galena as its alteration product; decimetric coatings with millimetric crystals; crossed habit, prisms, elongated crystals along a- and c-axis; white singular crystals and twin
  Twin
  A twin is one of two offspring produced in the same pregnancy. Twins can either be monozygotic , meaning that they develop from one zygote that splits and forms two embryos, or dizygotic because they develop from two separate eggs that are fertilized by two separate sperm.In contrast, a fetus...
  
  s.
• dolomite (CaMg (CO₃)₂): relatively rare; millimetric, rose coloured rhombohedra, sometimes displaying a saddle-shaped habit.
• galena (PbS): very common; crystals can reach several centimeters; occurs most often weathered (with a coating of iron oxide), often dull (due to oxidation), yet can display a brilliant luster and show excellent quality in some protected tension gashes; cubes and octahedra; grows on quartz, sometimes on calcite, dolomite or baryte; overgrown by cerussite, pyrite, marcasite, quartz and ozocerite.
• marcasite (FeS₂): very common low temperature mineral; prone to weathering; overgrows galena; often well formed millimetric singular crystals; decimetric coatings; cock's comb habit; twins after (110).
• ozocerite (pseudomineral): very rare; associated with quartz and galena; small (0.09 millimeter), brown spheres consisting of bitumen (mixture of liquid and solid carbohydrate
  Carbohydrate
  A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
  
  s of the methane
  Methane
  Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
  
  -family).
• pyrite (FeS₂): relatively rare; shperical aggregates on millimetric quartz crystals, in some places also on dolomite.
• pyromorphite (Pb₅[Cl/(PO₄)₃]): common; well formed crystals are rare; coatings on heavily altered galena; the galena can disappear altogether such that a boxwork of pyromorphite is left; faint yellow to deeply green crystals; light green, needle-shaped pyromorphite can grow in strongly altered enclaves within the granodiorite.
• quartz (SiO₂): common matrix mineral; very beautiful, 5 to 8 millimeter-sized, (double-ended) singular crystals on galena; can be covered by a thin coat of pyromorphite and some microcrystals of wulfenite; classical habit with badly developed prisms; colourless to milky; some individuals can be smoky or amethyst
  Amethyst
  Amethyst is a violet variety of quartz often used in jewelry. The name comes from the Ancient Greek ἀ a- and μέθυστος methustos , a reference to the belief that the stone protected its owner from drunkenness; the ancient Greeks and Romans wore amethyst and made drinking vessels of it in the belief...
  
  -like.
• sphalerite (ZnS): not very common; microcrystals associated with galena.
• wulfenite (Pb[MoO₄]): very rare; normally on dull green pyromorphite; very beautiful, orange-coloured, tabular, singular crystals that are 1 to 2 millimeters in size but can occasionally reach 1 centimeter; formed near the surface; the molybdenum
  Molybdenum
  Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
  
   probably derives from molybdenite
  Molybdenite
  Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms...
  
   finely disseminated within the granodiorite.

History

Quarrying started in the Tabataud quarry in the 1890s. The encountered ores were gathered, but the focus of the mining activities was the granodiorite itself. In the beginning the granodiorite was a highly esteemed building and cobble stone, but was milled later on mainly to gravel (for roadworks etc.). In 2003 the mining came to a final halt; since then the quarry is used as a storage area for the countless trees uprooted by cyclone Lothar

Lothar (storm)

Lothar is the name of a low-pressure system that resulted in a violent extratropical cyclone sweeping across Central Europe on December 26, 1999, causing major damage in France, southern Germany, and Switzerland. Wind speeds reached around 150 km/h in lower areas and more than 250 km/h on...

 in 1999.

Conclusions

The Tabataud quarry most probably yielded the finest galenas in the whole of France. It is furthermore one of the very few sites for wulfenite in France. As a rarity occurs the pseudomineral ozocerite. The cerussite is of extremely good quality and diversity.

The pegmatites, mineralized lodes and tension gashes all indicate an extensional tectonic setting within the granodiorite (dated as Serpukhovian

Serpukhovian

The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from 328.3 Ma tot 318.1 Ma...

), operative during its cooling stage. This enabled the pneumatolytic and hydrothermal solutions to deposit their dissolved mineral contents. The higher temperature pegmatites most likely preceded the hydrothermal deposits. A uranium-lead dating on galena yielded Lower Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 ages (300 to 250 million years BP). The spatial arrangement of the lodes and gashes hints at a transtensional, dextral shear zone

Shear zone

A shear zone is a very important structural discontinuity surface in the Earth's crust and upper mantle. It forms as a response to inhomogeneous deformation partitioning strain into planar or curviplanar high-strain zones. Intervening blocks stay relatively unaffected by the deformation...

oriented NW-SE.

Literature

• Duthou, J.-L. et al. (1974). Les gisements plombo-zincifères du seuil du Poitou et de sa bordure Limousine. Bulletin du BRGM, section II, n° 1, p. 453 -474.
• Floc'h, J.-P. et al. Feuille Nontron. Carte géologique de la France à 1/50 000. BRGM, Orléans.
• Guillemot, J., Lebocey, J. & Legrand, N. (2008). Minéralogie de la carrière Tabataud, Nontron, Dordogne. Le Règne Minéral, vol. 84, p. 27 – 33.