Table 2.

Lithological characteristics of the possible quarries that supplied the Menga dolmen.

Type	Classification of limestones based on the scheme of folk	Grain size (mm)	Mineralogical composition	Skeletal grains	No-skeletal grains	Matrix	Texture (Dunhan classification)	Microstructure and sedimentary structure	Sediment supply	Paleoenvironment	Quarry
1	Bioclastic calcirudite	2–25	70–80% calcite, 25–18% quartz, limestone, iron oxides, feldspar 5–2%	Main components: Bivalves (Clamys, pectinid), bryozoans Other components: Coralline corals, echinoids, benthic foraminifers (amphisteginas, globigerinas), brachiopods	Intraclasts (limestone, pellets)	Low sparite and absence of micrite	Rudstone	Syndepositional intergranular voids, parallel-laminatid	Factory zone	Submarine canyon	2
2	Bioclastic calcarenite	< 2	70–80% calcite, 25–18% quartz, limestone, iron oxides, feldspar and glauconite 5–2%	Main components: Coralline algae Other components: Bivalves, branching bryozoans, echinoderm spines	Pellets	Contains carbonate mud	Packstone-rudstone, crusts are bindstones	Syndepositional intergranular voids, parallel-laminatid	Factory zone	Submarine canyon	2
3	Bioclastic calcirudite/micro-breccia	> 2	70–80% calcite, 25–18% quartz, limestone, iron oxides, feldspar and glauconite 5–2%	Bivalves (pectinid), coralline algae, briyozoans	Pellets	Contains carbonate mud	Rudstone	Syndepositional intergranular voids, parallel-laminatid	Factory zone	Submarine canyon	3
4	Calcareous breccia	> 2	70% calcite, 15% quartz, 10% feldspar, iron oxides, (oncolites), sandstone and flint 2%. To a lesser extent: coal, slates	Bivalves, coraline algae, bryozoans	Oolitic limestone, dolomite, marly limestones, ophites	Contains carbonate mud	Rudstone	Synsedimentary cement, overlapping edges, parallet laminated, low-angle	River	Submarine canyon	1

Based on the classification Dunhan⁵¹ for carbonate rocks and Folk⁵⁰.