Tiruchirappalli District Mineral Foundation Trust
The Tiruchirappalli district exposes crystalline rocks of Archaean and Proterozoic age, Upper Gondwana Formations, sedimentary rocks of Mesozoic age, Miocene and Quaternary sediments.
The most significant geological features in Tiruchirappalli district include the "Trichinopoly Group" of Cretaceous rock formations.
The prominent Rock Fort hill made of crystalline rock.
Extensive deposits of garnet sand in areas like Musiri, Thuraiyur, and Thottiam.
Limestone and gypsum formations in the Dalmiapuram and Pullambadi regions.
And the presence of various igneous rocks like granite, charnockite, and gneiss, which are widespread throughout the district.
| Age | Group | Formation | Lithology and Fauna |
|---|---|---|---|
| Early Paleocene | NINIYUR | Niniyur (60 m) | Limestone: Nautilus danicus, Lyria formosa, Codakia percrassa, Algae, Foraminifera (Thalmannita madrugaensis, Triloculina trigonula etc), Ostracodes |
| Campanian to Maastrichtian | ARIYALUR | Kallamedu (100 m) | Sandstones and variegated clays, Reptilian fossil remains, Megalosaurus, Titanosaurus, Dinosaur: Bruhathakayosaun matleyi |
| Ottakovil (60 m) | Calcareous sandstones and siltstones. Echinoids: Stygmatopygus elatus, Lamellibranch: Durania mutabilis, Ammonite: Gunnarites kaklika, Pachydiscus otokodensis, Ichnofossils: Thalassinoides, Ophimorpha, Foraminifera: Globotruncana staurtiformis, Globotruncana arca | ||
| Kallankurichi (40 m) | Limestones and marls. Ammonite: Hauriceras rambda, Pachydiscus egertoni, Lamellibranch: Phygraca vesicularis, Exogyra tamulica, Rastellum (Arcostrea) pectinatum, Foraminifera: Globotruncana gansseri, Rugoglobigerina hexacamerata, Lepidorbitoides sp., Siderolites calcitrpoides, Ostracods, Echinoids: Stygmatoygus elatus | ||
| Sillakudi (500 m) | Sandstones with minor limestone. Ammonite: Karapadites karapadensis, Lamellibranchs: Inoceramus, Echinoids: Pentacrinus, Brachiopods: Cretirhynchia plicatiloides, Carneithyris carnea (Terebratulids), Foraminifera: Bolivinoides decoratus, Globigerinelloides asperus, Kathina minuscula | ||
| Coniacian-Santonian | TRICHINOPOLY | Anaipadi (100 m) | Sandstones, Siltstones and concretionary bodies. Ammonites: Placenticeras tamulicum, Kossmaticeras theoboldinum, Damesites sugota, Eubaculites otacodensis, Bivalve: Cardiceramus parareberti, Gastropods: Voysa aff. scalaroideum, Arcotia indica, Pseudomaura nobilis |
| Kulakkalnattam (50 m) | Limestone, sandstones, siltstones, and concretions of arenaceous limestones. Bivalve: Physa, Trigonia, Ammonites: Nautilus, Mespuzosia indopacificum, Placenticeras tamulicum, Kosmaticeras recurrens, Lewesiceras vaju, Allocovioceras sp., Gastropods: Gyrodes tenellus, Crytorhytis attenuata, Brachiopods: Cretirhynchia plicatiloides, Terebratulids | ||
| Upper Albian - Middle Turonian | UTTATUR | Karai Shale (400 m) | Ammonite: Mammites cancellatum, Eucalycoceras pentagonum, Calycoceras neuboldi, Schloenbachia inflata, Scaphites kingeanus, Turrilites costatus; Lamellibranchs: Pecten, Alectryonia; Serpulids, Crinoid spines, Belemnite guards; Foraminifera: Lenticulina kossmatina, Rotalipora cushmani, Marginotruncana indica, Helvetoglobotruncana helvetica, Planomalina buxtorfi, Ostracodes, Nannofossils: Chiastozygus litterarius, Microrhabdulus decoratus, Quadrum qartneri |
| Maravattur Clay (400 m) | Dark grey shale, Pyrites, Woody remains | ||
| Boulder Conglomerate (5 m) | |||
| Upper Gondwana | Terani plant beds (30 m) | Ptilophyllum acutifolium, Elatocladus conferta | |
| Archaean | Crystallines |