National Geological Monuments are geological areas of national importance as notified by the Geological Survey of India. These geoheritage sites are notified in an effort to improve their maintenance, protection, promotion and enhancement of geotourism. The Geological Survey of India and the respective state governments are responsible for taking necessary measures to protect these sites.
, there are 35 notified National Geological Monuments. The National Fossil Wood Parks at Tiruvakkarai and Sathanur in Tamil Nadu were the first to be declared as National Geological Monuments in 1951. With 12 sites, Rajasthan has the most such monuments, followed by Karnataka (5) and Andhra Pradesh and Tamil Nadu (4 each).
List of National Geological Monuments
+List of National Geological MonumentsNameImageLocationStateNotes1951National Fossil Wood Park, TiruvakkaraiThiruvakkarai, Viluppuram districtTamil NaduFossil remains of conifer and palm trees from the Miocene–Pliocene epochs, transported by rivers and later fossilised after the wood was replaced by silica from the sediments.1951National Fossil Wood Park, SathanurSathanur, Perambalur districtTamil NaduPetrified gymnosperms from the Late Cretaceous (100.5–66 Ma), formed on eroded granulite rocks.1972Akal Wood Fossil ParkAkal, Jaisalmer districtRajasthanPetrified wood and fossilised tree trunks from the Lower Jurassic (~180 Ma) over a area, along with fossils of invertebrates such as gastropods and ammonites, which were formed when forests in warm, humid climate bordering the sea were rapidly buried in sediments and followed by replacement of the wood by silica.1974Shivalik Fossil ParkSuketi, Sirmaur districtHimachal PradeshFossils of vertebrates dating to 1 to 1.5 Ma found in the Sivalik Hills of the Himalayas.1975Charnockite, St. Thomas MountChennai, Chennai districtTamil NaduA type of Charnockite bearing quartz–feldspar–hypersthene, formed at high temperature and pressure by the metamorphism of igneous rock.1975Pillow lavas, MaradihalliHiriyur, Chitradurga districtKarnatakaPillow lavas occurring on a schist rock hillock, dating to the Precambrian period (2.5 Ga).1975Peninsular Gneiss of LalbaghBengaluru, Bengaluru Urban districtKarnatakaPeninsular Gneiss rock occurring on an exposed small hillock located in the Lal Bagh gardens, dating to 2.5 to 3.4 Ga.1975Columnar Basalt, Coconut IslandsSt. Mary's Islands, Udupi districtKarnatakaBasalt columns developed by the rapid cooling of lava flows, found on flat-topped hills in four islands off the coast of Malpe in the Deccan Traps region, dating to the Cretaceous–Eocene (about 60 Ma).1976Bhojunda Stromatolite ParkBhojunda, Chittaurgarh districtRajasthanStromatolites, layered sedimentary formations created by blue-green algae through the bonding of carbonate particles, occurring on limestone rocks and dating to 900 Ma, when the sea levels were higher and the region was covered by shallow water.1976Eparchaean UnconformitySapthagiri, Tirupati districtAndhra PradeshA significant stratigraphic discontinuity in the Earth's geological history, where gneisses formed during the Archean (4 to 2.5 Ga) meet the sedimentary rocks of the Proterozoic (2.5 to 0.54 Ma) of the Kadapa sub-group.1976Eddy Current Markings, KadanaKadana, Mahisagar districtGujaratFossilised markings on sandstone and quartzite rocks formed during the orogeny of the Aravalli Range, when soft sedimentary rocks from the Proterozoic were metamorphosed.1976Great Boundary Fault, SaturSatur, Bundi districtRajasthanFaults in the region between the Aravalli and the Vindhya Ranges that separate the younger sedimentary rocks of the Vindhyas, formed about 900 Ma, from the older pre-Aravalli rocks.1976Jodhpur Group – Malani Igneous Suite ContactJodhpur, Jodhpur districtRajasthanIgneous suite formed during the Precambrian period and overlain by sedimentary rocks in the Proterozoic and early Cambrian (540 Ma). The hillock on which the Mehrangarh fort stands displays a visible nonconformity between the rock layers.1976Pillow Lava, Iron ore belt, NomiraNomira, Kendujhar districtOdishaPillow lavas and tuffs formed from submarine volcanic activity during the Archean. These were later overlain by shale, hematite, jasper, and quartzite, and are now part of an exposed rock surface.1976Nepheline syenite, KishangarhKishangarh, Ajmer districtRajasthanIntrusions of Syenite and Nepheline into metamorphic rocks of the Aravalli Range, dating to the Precambrian period (1.91 to 1.59 Ga).1976Plant Fossil bearing Inter-trappean beds of Rajmahal FormationMandro, Sahibganj districtJharkhandPlant fossils dating to 145 to 68 Ma, found in intertrappean beds, which are thin sedimentary rock layers sandwiched between successive basaltic lava flows.1976Gossan in Rajpura–Dariba Mineralised beltRajpura–Dariba, Rajsamand districtRajasthanThick, colourful gossan formed through prolonged weathering and oxidation of sulfide minerals such as sphalerite, galena, and chalcopyrite. Remnants of ancient mining are evidenced, dating to 3040 ± 150 BP, contemporary with the Indus Valley Civilisation.1976Jhamarkotra Stromatolite ParkJhamarkotra, Udaipur districtRajasthanThe world's largest phosphorite deposits, containing algal stromatolite fossils in Proterozoic Aravalli dolomitic limestone (~1.8 Ga).1976Pyroclastic rocks, PeddapalliPeddapalli, Kolar districtKarnatakaWelded agglomerate of rounded to angular fragments of granite, gneiss, basalt, and banded ferruginous quartzite set in an ignimbrite matrix, formed around 2.9 Ga during submarine volcanic activity. The pyroclastic rocks are part of the Kolar Schist Belt and represent violent, glowing avalanche-type volcanic eruptions.1976Welded Tuff, JodhpurJodhpur, Jodhpur districtRajasthanWelded tuff composed of volcanic ejecta containing glass, quartz, and feldspar, which developed columnar joints and terraces upon cooling. Varied coloured Malani rhyolites are interlayered with tuff and pyroclastic rocks.1977Barr ConglomerateBarr, Pali districtRajasthanPebbles of quartzite and aplite, along with fine grained schists consisting of mica, set on underlying gneiss.1977Sendra GraniteBeawar, Pali districtRajasthanOld granite dating to ~1.2 Ga intruded the Beawar lithostratigraphic rock unit, dating ~1.5 Ga, which was exposed after uplift and weathered over the last 500 Ma.1979Lonar LakeLonar, Buldhana districtMaharashtraA saline and soda lake in an impact crater formed by a hyper-velocity meteorite impact about 50 ka ago. The wide, deep impact structure is one of the youngest and best-preserved impact structures on Earth, with compact, vesicular and amygdaloidal basalt exposed around the crater.1979Angadipuram LateriteAngadipuram, Malappuram districtKeralaLaterite deposits along the Arabian Sea coast, featuring a unique combination of pyroxene granulite, charnockite, and migmatite.1981Natural Geological ArchTirumala, Tirupati districtAndhra PradeshA natural arch, wide and high, formed by weathering of quartzite rocks dating to Middle to Upper Proterozoic (1.6 to 0.53 Ga).1982Bedded Barytes, MangampetMangampeta, Annamayya districtAndhra PradeshSingle largest baryte (mineral of Barium sulphate) deposit in the world, through precipitation of volcanic vapours and deposition of volcanic ash under submarine conditions during the Proterozoic (2.5 to 0.53 Ga).1983Marine Gondwana Fossil ParkAmmakherwa, Surguja districtChhattisgarhA fossil park preserving marine Permian fossils (280–240 Ma) of invertebrate such as Eurydesma, Aviculopecten, bryozoans, crinoids, and foraminifers, within the carbonaceous shale of the Talcher Formation of the Gondwana Supergroup. The diverse , records a Permian marine transgression into central India.2001Naga Hills OphiolitePungro, Kiphire districtNagalandThe Naga Hill Ophiolite is an example of oceanic lithosphere obducted onto continental crust, consisting of Mesozoic–Cenozoic magmatic and sedimentary rocks, along the Indo–Burma convergence zone.2014Stromatolite bearing Dolomite / Limestone of Buxa Formation at MamleyNamchi, South Sikkim districtSikkimThe site exposes dolostones of the Proterozoic Buxa Formation of the Daling Group, which are stromatolitic structures formed by algae during the Precambrian, and preserve rare evidence of early life in the Eastern Himalayas.2015Badlands of Karai FormationKarai, Perambalur districtTamil NaduFossils from the Late Cretaceous found along Karai – Kulakkalnattam section, deposited in the Karai Formation, a Mesozoic (252 to 66 Ma) geological formation composed of gypsiferous mudstone, silty sandy clay, and sandstone deposited in a dry basin.2015Varkala Cliff SectionVarkala, Thiruvananthapuram districtKeralaWarkalli cliff formations along a stretch of the Arabian Sea coast, formed by erosion during the Miocene–Pliocene (23 to 2.58 Ma).2016Erra Matti DibbaluVishakhapatnam–Bheemunipatnam, Visakhapatnam districtAndhra PradeshDissected and stabilized red sand mounds along the Bay of Bengal coast between Vishakhapatnam and Bheemunipatnam, formed by erosion of deposited sediments.2018Ramgarh craterRamgarh, Baran districtRajasthanAn eroded impact crater in the Mesoproterozoic Vindhyan Supergroup (1.6–1.0 Ga) that consists of iron-rich impact spherules and coesite, which indicates that the crater was formed by the impact of a copper-rich iron meteorite.2018Zawar Lead–Zinc mineZawar, Udaipur districtRajasthanThe lead–zinc mine is part of the Paleoproterozoic Aravalli Supergroup, where sulphide minerals occurs within a carbonate-bearing sequence of metamorphosed sediments in an extensional rift basin and is known for its ancient zinc-mining and smelting.2026Yana CavesYana, Uttara KannadaKarnatakaCaves formed in Precambrian dolomitic limestone dating to ~2.7 Ga and exposed by epeirogenic movement. Prolonged tropical weathering and chemical dissolution from percolating rainwater resulted in distinctive karst landforms, with fissures, caverns, and sinkholes.
Geo-tourism sites in Northeast India
In 2021, the Geological Survey of India listed 12 sites in Northeast India for the promotion of geo-tourism. These included two declared National Geoheritage Sites of Mamley Stromatolite Park and Nagahill Ophiolite Site.