GEOLOGICAL TIME SCALE
AND INDIAN STRATIGRAPHY
PREPARED BY ,
TONY S CHERIYATHU
IIIRD B.Sc. GEOLOGY
INTRODUCTION
IT IS A SYSTEM OF CHRONOLOGICAL DATING THAT RELATES GEOLOGICAL STRATA
TO TIME
THE GEOLOGICAL TIME SCALE IS A RECORD OF THE LIFE FORMS AND
GEOLOGICAL EVENTS IN EARTH HISTORY
THE TIME SCALE WAS DEVELOPED BY STUDYING ROCK LAYERS AND FOSSILS
WORLDWIDE. RADIOACTIVE DATING HELPED DETERMINE THE ABSOLUTE DIVISIONS
IN THE TIME SCALE.
THE LARFGEST SECTIONS OF TIME SCALE ARE CALLED “EONS” , EONS ARE DIVIDED
INTO “ERAS”, ERAS ARE DIVIDED INTO “PERIODS” , PERIODS ARE DIVIDED INTO
“EPOCH”
PRECAMBRIAN PERIOD (4500-541ma)
OLDEST AND LONGEST PERIOD [HENCE CALLED SUPER EON] IN THE HISTORY OF EARTH
IT COVERS APPROXIMATELY 88% OF EARTH HISTORY.
PRECAMBRIAN SUPER EON IS FURTHER DIVIDED INTO 3 SPECIFIC EONS WHICH ARE
HADEAN , ARCHEAN AND PROTEROZOIC
HADEAN EON (4500-3800ma)
THE WORD ‘HADEAN’ IS DERIVED FROM THE WORD ‘HADES’ MEANS
HELL
IT BEGAN WITH FORMATION OF THE EARTH
FORMATION OF EARTH CRUST BY COOLING
4 BILLION YERS AGO , TERRESTRIAL CRUST WAS FORMED FOLLOWED
BY THE CONTINENT AND OCEAN
ARCHEAN EON (4000-2500ma)
THE WORD ‘ARCHEAN’ DERIVED FROM ‘ARKHE’ MEANS
BEGINNING OR ORGIN
THE OLDEST DATED ROCK ARE FOUND
THE BEGINNING OF PROKARYOTIC ORGANISM AND PRESENCE
OF OXYGEN IS ASSUMED DURING THIS EON
CYANOBACTERIA OR BLUE GREEN ALGAE WERE THE FIRST
MICRO ORGANISM TO APPEAR ON EARTH WHICH FORMS
CALCAREOUS CONCRETIONS ON THE ROCK EXISTED DURING
THAT TIME , STROMATOLITES WERE THE EVIDENCE OF FIRST LIFE
FORMS
INDIAN OCCURANCE
1. ARCHEAN ROCKS AND GRANITES (PREMARILY GNEISS AND GRANITE) ;
THE ARCHEAN ROCKS COVERS TWO THIRDS OF THE PENINSULAR INDIA
.THE ARCHEAN FORMATIONS IN THE INDIAN SHIELD OCCUPIES MOST OF
THE SOUTHERN AND EASTERN INDIA AND PARTS OF ASSAM ,JHARKAND
,MADHYAPRADESH AND RAJASTHAN
2. DHARWAD ROCKS(WEATHERING OF ARCHEAN SHIST AND GNEISS ROCK
PRODUCE SEDIMENTS WHICH LATER GET METAMORPHISED INTO
DHARWAD ROCK[BOTH SEDIMENTARY AND METAMORPHIC]).LARGE
AMOUNT OF GOLD , IRON , LEAD ETC ARE FOUND IN THIS ROCKS.
MAJORLY OCCURS IN DHARWAD ,KARNATAKA ,JHARKAND
MADHYAPRADESH,CHATTISGHARH,ODISHA , ARAVALI HILLS, HIMALAYAS
AND MEGHALAYA PLATEAU ETC.
ARCHEAN GRANITES AND GNEISS DARWAD ROCKS
PROTEROZOIC EON (2500-541ma)
IT IS SUBDIVIDED INTO THREE GEOLOGIC ERAS (FROM OLDEST TO
YOUNGEST): THE PALEOPROTEROZOIC, MESOPROTEROZOIC,
AND NEOPROTEROZOIC.
THE WELL IDENTIFIED EVENTS OF THIS EON WHERE THE TRANSITION
TO THE OXYGENATED ATHMOSPHERE , BEGINNING OF THE
MOUNTAIN FORMATION , EVOLUTION OF EUKARYOTES , SEVERAL
GLACIATIONS , FORMATION OF MULTI CELLED CREATURES [WITH
NO HARD PARTS LIKE SHELL OR TEETH ,SO FOSSILS ARE HARD TO
FIND]
INDIAN OCCURANCE
1. CUDDAPAH ROCKS (DHARWARD ROCKS WEATHERED AND DEPOSITED
INTO THE SYNCLINAL BASIN) IT MAY HAVE THICKNESS UPTO 6000
METERS.THEY ARE GENERALLY WITHOUT FOSSILS. CONTAIN ORES OF IRON ,
COBALT , NICKEL ETC . FOUND IN CUDDAPAH(ANDRA PRADESH) ,ODISHA,
CHATHISGARH AND KARNATAKA. ALSO FOUND IN DELHI TO ARAVALI
AND GUJARAT.
2. VIDHYAN ROCKS (DIAMOND BEARING Eg. GOLCONDA MINES)USED AS
SANDSTONE ,BUILDING MATERIAL, RAW MATERIAL FOR CEMENT
CHEMICAL INDUSTRIES ETC.,USUALLY CONSIST OF ENORMOUS
SEDIMENTARY DEPOSITS.IT STRECHES FROM SASARAM IN BIHAR TO
CHITTOGARH IN RAJASTHAN
CUDDAPAH ROCK VIDHYAN ROCKS
PHANEROZOIC EON (541ma-PRESENT)
IT IS THE PRSENT EON
THE WORD ‘PHANEROZOIC’ MEANS VISIBLE LIFE
THEY ARE DIVIDED INTO 3 ERAS- PALEOZOIC , MESOZOIC AND CENOZOIC
PALEOZOIC ERA (541-248ma)
IT MEANS THE ‘ANCIENT LIFE’ IN GREEK
IT IS KNOWN FOR THE VARIETY OF LIFE THAT RAPIDLY BEGAN TO APPEAR .
THE PALEOZOIC ERA CAN BE SUBDIVIDED INTO SIX PERIODS ; CAMBRIAN ,
ORDOVICIAN , SILURIAN , DEVONIAN , CARBONIFEROUS AND PERMIAN
THIS IS KNOWN AS “DRAVIDIAN ERA” IN THE GEOLOGICAL TIME SCALE . IT IS
ALMOST ABSENT IN PENINSULAR REGION BUT ARE FOUND IN CONTINUOUS
SEQUENCE IN HIAMLAYAS
CAMBRIAN (541-505ma)
EXPLOSION OF LIFE
ALL EXISTING MAJOR BODY PLANS (PHYLA) CAME INTO BEING THIS
TIME
VARIOUS GROUP OF INVERRTIBRATES EVOLVED IN THE SHALLOW SEAS
THAT COVERED MUCH OF THE EARTH
TRILOBITE IS AN INVERTEBRATE WITH HARD EXOSKELETON AND BODY IS
DIVIDED INTO 3 LOBES
SUPERCONTINENT GODWANA FORMS NEAR THE SOUTH POLE
INDIAN OCCURANCE
PLENTY OF FOSSIL EVIDENCE ARE OBTAINED
FROM INDIAN ROCKS (LIKE THAT OF CORALS ,
FORMINIFERAS , SPONGES ,TRILOBITES ETC.
WHICH INDICATE MARINE CONDITIONS OF
PALEOZOIC ROCKS FOUND IN INDIA) Eg. THE
SALT RANGE , THE SPITI AREA , THE FORMATION
OF KASHMIRI VALLEY ETC.
ORDOVICIAN (505-438ma)
THE FIRST ANIMAL WITH BONES APPEARS [AGNATHS , FISH
WITH NO JAWS]
THERE WERE ALSO GREAT QUANTITIES OF CORALS ,SPONGES
AND MOLLUSKS SUCH AS CEPHALOPODS
AGNATHS
4 MAIN CONTINENTS ; GODWANA , BALATICA , SIBERIA ,
AND LAURENTIA
CEPHALOPODS
INDIAN OCCURANCE
THE ORDOVICIAN SYSTEM IS EXPOSED IN THE NORTHERN
KUMAON-SHIMLA REGION CONTAINING MAINLY
SHALES .
THE ORDOVICIAN ROCKS OF KASHMIR IS EXPOSED IN
THE LIDAR VALLEY
SILURIAN (438-410ma)
FIRST LAND BASED PLANT GREW [COOKSONIA(STEM WITH NO
ROOT OR LEAVES)]
FISH WITH JAWS BEGAN TO APPEAR[ACANTHODIANS, THEIR
COOKSONIA
FINS HAD LONG SPINES]
LAURENTIA COLLIDES WITH BALTICA AND CLOSES LEPITUS SEA
ACANTHODIANS
INDIAN OCCURANCE
THE SILURIAN ROCKS ARE SEEN IN SPITI REGION THEY
CONTAINING RED CRINOIDAL LIMESTONE OF
GRIESBACH AND ZANSKAR RANGE .
THE SILURIAN ROCKS OF KASHMIR ARE EXPOSED IN THE
LIDAR VALLEY
DEVONIAN (410-360ma)
PRE PANGEA FORMS
ARRIVAL OF INSECTS [THE OLDEST INSECT KNOWN IS
ARCHEOGNATH] ARCHEOGNATH
THE FIRST LAND BASED ANIMALS ; AMPHIBIANS[FINS OF
SOME FISH WERE TRANSFORMED INTO LIMBS. THE
ICHTHYOSTEGA WAS ONE OF THE FIRST AMPHIBIAN TO
EVOLVE]
FISHES BEGAN TO DIVERSIFY AND FERNS BEGAN TO
GROW ON WATER EDGE
ICHTHYOSTEGA
INDIAN OCCURANCE
THE DEVONIAN SYSTEM OF ROCKS ARE REPRESENTED BY
THE MUTH QUARTZITE OF SPITI , KUMAON AND KASHMIR.
LIMESTOME WITH BRACHIPODS AND CORALS THAT ARE
EXPOSED IN THESE ROCKS
CARBONIFEROUS (360-286ma)
IT IS DIVIDED INTO MISSISSIPPIAN [360-320ma] AND
PENNSYLVANIAN [320-286ma]
MISSISSIPPIAN : FIRST SEED PLANT APPEARS
PENNSYLVANIAN ; THE FIRST REPTILES APPEARED ,THE OLDEST
WINGED INSECTS LIKE GIANT MEGANEURA DRAGONFLY
APPEARS , MODERN NORTH AMERICA BEGAN TO FORM
RISE IN SEA LEVEL FORMED HUGE MARSHES . ALL OF THE
VEGETATION DIED AND DECOMPOSED TO FORM COAL.
INDIAN OCCURANCE
THE CARBONIFEROUS SYSTEM OF ROCKS IN INDIA ARE
DISTRIBUTED ONLY IN AFEW PLACES IN THE
HIMALAYAN REGION IN KASHMIR . THEY CONTAIN
FOSSILIFEROUS LIMESTONE AND SHALES. THEY ARE
CALLED AS LIPAK AND PO SERIES
PERMIAN (286-248ma)
PANGEA FORMS
REPTILES SPREAD ACROSS CONTINENTS
THE CLIMATE BECOME COOLER AND DRIER
THE RISE OF APPALACHIAN
90% OF EARTH SPECIES BECOME EXTINCT DUE TO
VOLCANISM IN SIBERIA , LOWERING OF SEA LEVELS
AND CLIMATIC CHANGES
INDIAN OCCURANCE
THE UPPER CARBONIFEROUS AND PERMIAN SYSTEMS OF
INDIA CONTAIN UNIQUE FAUNA AND FLORA. THEY ARE
EXPOSED IN SPITI, KUMAON, MOUNT EVEREST REGION,
ASSAM , HIMALAYA, KASHMIR-PANJAL VOLCANIC SERIES,
SIMLA-GARHWAL-KROL SERIES AND IN EASTERN
HIMALAYAN REGIONS LIKE SIKKIM.
MESOZOIC ERA (248-65ma)
CONSIST OF THREE PERIODS ; TRIASSIC , JURASSIC AND CRETACEOUS
TRIASSIC (248-208ma)
FIRST DINOSAURS APPEAR
PANGEA BREAK APART
ROCKY MOUNTAIN FORMS
FIRST MAMMALS AND SMALL RODENTS APPEARED
INDIAN OCCURANCE
THIS PERIOD HAS SHOWN A VERY RICH AND VARIED FAUNA AND FLORA.
NUMEROUS INVERTEBRATE FOSSILS, INCLUDING CERATITES, AMMONOIDS,
BRACHIOPODS, CRINOIDS, ECHINOIDS AND PELECYPODS HAVE BEEN
OBSERVED IN THE ROCKS OF THIS AGE. AMONGST THE VERTEBRATES,
FISHES ARE QUITE ABUNDANT.
IN INDIA, THEY ARE EXPOSED AS ; THE LILANG SYSTEM IN SPITI, NORTHERN
KUMAON, THE CHOCOLATE SERIES, THE KALAPANI LIMESTONE ,THE KUTI
SHALES.
GODWANA ROCK ; USALLY SHOWN FROM CARBONIFEROUS PERIOD TO
JURASSIC PERIOD . THE MAIN AREAS IN WHICH IT IS FOUND ARE
DAMODAR VALLEY , MAHANADHI VALLEY AND GODAWARI VALLEY.
THEY CONTAIN 98% OF COAL IN INDIA AND HAVE RICH DEPOSIT OF
COPPER , IRON , URANIUM ETC.
GODWANA ROCK
JURASSIC (208-145ma)
AGE OF THE DINOSAURS OR REPTILES
FORMATION OF ATLANTIC OCEAN
GYMNOSPERMS DOMINATED DURING THIS PERIOD
BIRDS EVOLVED
INDIAN OCCURANCE
THE JURASSIC SYSTEM IS EXPOSED AS SPITI SHALES,
LAPTAL SERIES OF KUMAON, MOUNT EVEREST
REGION, SUB-HIMALAYA OF GARHWAL, KUTCH
AND RAJASTHAN AREAS.
THE MARINE TRANSGRESSION IN THE LATTER PART
OF THE JURASSIC GAVE RISE TO THICK SERIES OF
SHALLOW WATER DEPOSITS IN RAJASTHAN AND IN
KUCHCHH.
CORAL LIMESTONE, SANDSTONE,
CONGLOMERATES AND SHALES OCCUR IN
KUCHCHH.
CRETACEOUS (145-65ma)
MASS EXTINCTION OF PLANTS AND ANIMALS (ASTERIOD
OR COMETS COLLIDES WITH EARTH)
DISSAPPEARENCE OF THE DINOSAURS
ANGIOSPERMS DOMINATED DURING THIS PERIOD
FORMATION OF THE ALPS
LARGE DEPOSITION OF CACO3
INDIAN OCCURANCE
THIS PERIOD IS MARKED BY THE TRANSGRESSION OF THE SEA
(COROMANDAL COAST, NARMADA VALLEY) AND
OUTPOURING OF HUGE QUANTITY OF LAVA (BASALT) SO AS
TO FORM THE DECCAN TRAP.
DURING THIS PERIOD, ENORMOUS QUANTITY OF BASALTIC
LAVA WAS POURED OUT TO THE SURFACE ASSUMING A GREAT
THICKNESS OF OVER THREE THOUSAND METRES. THE LAVA
PLATEAU (THE DECCAN TRAP) IS THE RESULT OF THAT LAVA
ERUPTION.
THE LAVA PLATEAU OF INDIA (DECCAN TRAP) HAS A
MAXIMUM THICKNESS OF ABOUT 3000 M ALONG THE COAST
OF MUMBAI FROM WHERE IT DECREASES TOWARDS SOUTH
AND EAST.PRESENT DECCAN TRAP COVERS ABOUT 5 LAKH sq
Km PARTS OF KUCHCHH , SAURASHTRA , MAHARASHTRA , THE
MALWA PLATEAU AND NORTHERN KARNATAKA ETC
THE DECCAN TRAP
CENOZOIC ERA (65ma-PRESENT)
CENOZOIC ERA IS DIVIDED INTO 2 PERIODS ; TERTIARY AND QUANTENARY
TERTIARY (65-1.6ma)
DIVIDED INTO 5 EPOCHS ; PALEOCENE ,EOCENE ,
OLIGOCENE , MIOCENE AND PLIOCENE
FIRST GRASSES
DIVERSIFICATION OF MAMMALS
FIRST PRIMATES
INDIAN OCCURANCE
FORMATION OF THE HIMALAYAS
INDIAN SUBCONTINENT BROKE APART FROM THE
SUPERCONTINENT PANGEA
THESE SYSTEM ARE FOUND IN SALT RANGE , BENGAL
AND GANGES DELTA . SMALL PATCHES ARE SEEN
ALONG THE COASTAL KERALA , KARNATAKA AND
GUJARAT,KATHIAWAR AND KUTCH REGIONS.
QUATERNARY (1.6ma-PRESENT)
DIVIDED INTO TWO EPOCH ; PLEISTOCENE AND HOLOCENE
PUNCTUATED BY 4 ICE AGES
FIRST HUMAN APPEARS , DOMINATED BY HUMANS
INVENTION OF WRITING 5000 YEARS AGO
INDIAN OCCURANCE
THE NORTHERN PLAINS OF INDIA CAME INTO
EXISTENCE DURING THE PLEISTOCENE PERIOD
THE MORAINE DEPOSITS AND THE KAREWA
FORMATIONS OF KASHMIR VALLEY ARE OF THE
PLEISTOCENE PERIOD
THE RIVER TERRACES OF THE NARMADA, TAPI,
GODAVARI, KRISHNA, AND KAVERI, ETC. ARE ALSO
OF THE PLEISTOCENE PERIOD.
