Intertrappean Beds

Intertrappean Beds
Stratigraphic range: Maastrichtian-Ypresian, 67.7–56 Ma
TypeUnit
Unit ofDeccan Traps
OverliesInfratrappean Beds
Location
Coordinates17°12′N 77°54′E / 17.2°N 77.9°E / 17.2; 77.9
Approximate paleocoordinates28°00′S 59°00′E / 28.0°S 59.0°E / -28.0; 59.0
RegionMadhya Pradesh, Maharashtra, Telangana, Gujarat, Uttar Pradesh, Andhra Pradesh, Karnataka
CountryIndia
Intertrappean Beds is located in India
Intertrappean Beds
Intertrappean Beds (India)

The Intertrappean Beds are a Late Cretaceous and early Paleogene geologic unit in India. These beds are found as interbeds between Deccan Traps layers, including the slightly older Lameta Formation. They consist a number of different subgroups and formations, and span the Cretaceous–Paleogene boundary.

Many mostly fragmentary fossils, especially of small vertebrates, are known from the formation. Indeterminate theropod and pterosaur remains have been recovered from the formation, as well as dinosaur eggs. The mammal genera Deccanolestes, Sahnitherium, Bharattherium, Indoclemensia, Indotriconodon and Kharmerungulatum have been recovered from several localities. The Early Eocene-aged Bamanbor locality in Gujarat preserves articulated freshwater fish specimens. A rich plant flora is known from the formation.

Stratigraphy

Although often thought of as a contemporaneous unit that was formed in a single rapid eruption event, more studies that date the age of the volcanic beds indicate that the Deccan Traps did not erupt all at once. Instead, different portions appear to have erupted during different periods of time. This means that the Intertrappean Beds are best understood as a group of different volcanic-associate formations of varying ages.

Divisions

Kale et al (2020) divided the group into the following provinces:

  • Sahyadri Group or Western Province (age: Late Maastrichtian to Danian, ~67.5 to 62.5 mya)
  • Satpura Group or Central Province
  • Malwa Group (age: Late Maastrichtian, ~67.7 mya; likely the oldest group)
  • Amarkantak Group or Mandla Province (age: early Paleogene, ~64.5 mya - unknown)

Mittal et al (2021) divided the group into the following provinces:

  • Western Ghats-Central Indian Volcanic Province (WVP) (age: Late Maastrichtian to Danian)
  • Saurhastra-Kutchh Province (age: ?Maastrichtian to early Eocene)
  • Malwa Plateau Province (age: Late Maastrichtian)
  • Mandla Lobe Province (age: early Paleogene)

Formations

Chemostratigraphic definition

Kale et al (2020) divided the group as follows. Subgroups/formations are classified based on oldest to youngest.

  • Wai Subgroup (youngest)
    • Desur Formation
    • Panhala Formation
    • Mahabaleshwar Formation (~63.2 mya)
    • Ambenali Formation
    • Poladpur Formation
  • Lonavala Subgroup
    • Bushe Formation
    • Khandala Formation
  • Kalsubai Subgroup (oldest, ~67.5 mya)
    • Bhimashankar Formation
    • Thakurwadi Formation
    • Neral Formation
    • Igatpuri Formation
    • Jawhar Formation

Lithostratigraphic definition

Kale et al (2020) divided the group as follows. Subgroups/formations are classified based on oldest to youngest.

  • Sahyadri Group:
    • Bombay Subgroup (~62.5 mya)
      • Borivali Formation
      • Elephanta Formation
    • Khandala Subgroup (~67.5 to 63.2 mya)
      • Mahabaleshwar Formation (~63.2 mya)
      • Purandargarh Formation
      • Diveghat Formation
      • Karla Formation
      • Indrayani Formation
    • Kalsubai Subgroup (oldest: ~67.5 mya)
      • Upper Ratangarh Formation
      • Lower Ratangarh Formation
      • Salher Formation
  • Satpura Group:
    • Karanja Formation (youngest)
    • Buldhana Formation
    • Chikli Formation
    • Ajanta Formation
    • Upper Ratangarh Formation
    • Karanja Formation
    • Buldana Formation
    • Chikli Formation (oldest)
  • Malwa Group:
    • Singarchori Formation (youngest)
    • Bargonda Formation
    • Indore Formation
    • Kankaria-Pirukheri Formation
    • Kalisindh Formation
    • Mandleshwar Formation
    • Gaganwara Formation (oldest)
  • Amarkantak Group:
    • Kuleru Formation (youngest)
    • Khamla/Kampla Formation
    • Amarwara Formation
    • Multai Formation
    • Linga Formation
    • Pipardehi Formation
    • Dhuma Formation
    • Mandla Formation (oldest, ~64.4 mya)

Within the newly defined Saurhastra Group (age: Paleocene to early Eocene), the following divisions were found by Patel & Shah (2023):

  • Ninama Basin:
    • Ninama Limestone (youngest)
    • Sukhbhadar Formation (oldest)
  • Chotila Basin:
    • Bamanbor Formation (youngest)
    • Chotila Chert
    • Rangpar Formation (oldest)

Paleobiota

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon

Notes
Uncertain or tentative taxa are in small text
crossed out taxa are discredited.

Fish

Genus Species Location Stratigraphic position Material Notes Images
Anthracoperca A. bhatiai Naskal, Rangapur Otolith. A percoid otolith.
Apateodus A. striatus Asifabad An enchodontoid aulopiform.
Ariidae incertae sedis Naskal, Rangapur, Anjar Otolith. An ariid catfish otolith.
?Belonostomus B. indicus Nagpur An aspidorhynchid.
Coupatezia C. sp Asifabad An eagle ray.
Cyprinidae incertae sedis Deothan-Kheri A cyprinid.
Dapalis D. erici Rangapur Otolith. A serranid otolith.
"Eotrigonodon" "E." wardhaensis Asifabad Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts.
Enchodus E. sp Asifabad An enchodontoid aulopiform.
Horaclupea H. intertrappea Bamanbor Early Eocene Complete skeleton. A clupeid.
Igdabatis I. indicus Kisalpuri & Piplanarayanwar An eagle ray.
Indiaichthys I. bamanborensis Bamanbor Early Eocene Multiple complete skeletons. A possible percoid.
"Indotrigonodon" "I." ovatus Asifabad Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts.
"Lepidotes" "L." sp Asifabad A lepisosteiform.
Lepisosteus L. indicus Kisalpuri & Piplanarayanwar A gar.
Nandidae incertae sedis Deothan-Kheri A nandid.
Osteoglossidae incertae sedis Kisalpuri & Piplanarayanwar An osteoglossid of uncertain affinities.
Palaeolabrus P. dormaalensis Asifabad A palaeolabrid.
Palaeopristolepis P. chiplonkari Bamanbor Early Eocene Multiple partial skeletons. A questionable leaffish.
P. feddeni
"Perca" "P." angusta Bamanbor Early Eocene Skull. A possible percoid, classification very doubtful.
Percomorpha incertae sedis Bamanbor Early Eocene Partial skeleton. A percomorph of uncertain affinities.
Phareodus P. sp. Asifabad, Naskal & Marepalli A bonytongue.
Polycanthidae incertae sedis Deothan-Kheri A polycanthid.
"Pisdurodon" "P." spatulatus Asifabad Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts.
Pycnodontidae incertae sedis Kisalpuri & Piplanarayanwar A pycnodontid of uncertain affinities.
"Pycnodus" "P." lametae Asifabad A pycnodontid.
Raja R. sudhakari Asifabad A skate.
Rhombodus R. sp. Asifabad A stingray.
Serranidae incertae sedis Deothan-Kheri A serranid.
Siluriformes incertae sedis Kisalpuri & Piplanarayanwar A catfish of uncertain affinities.
Sphenodus S. sp. Asifabad A shark.
Stephanodus S. lybicus Asifabad & Marepalli A pycnodontid.

Otolith-based taxa

Genus Species Location Stratigraphic position Material Notes Images
Ambassidarum A. cappettai Nagpur Otolith An ambassid otolith.
Apogonidarum A. curvatus Naskal, Rangapur Otolith A cardinalfish otolith.
Blenniidarum B. sp Rangapur Otolith A blenny otolith.
?Centropomidarum C. takliensis Nagpur Otolith A possible snook otolith.
Clupeidarum C. valdiyai Nagpur, Rangapur Otolith A clupeid otolith.
C. sahnii
Gonorhynchidarum G. rectangulus Nagpur, Rangapur Otolith A gonorynchid otolith.
Heterotidinarum H. heterotoides Naskal Otolith An arapaimine otolith.
Notopteridarum N. nolfi Naskal, Rangapur, Cheemalagutta Otolith A notopterid otolith.
Osteoglossidarum O. deccanensis Naskal, Otolith An osteoglossid otolith.
O. intertrappus
Percoideorum P. citreum Naskal, Nagpur, Rangapur Otolith Percoid otoliths.
P. nagpurensis
P. rangapurensis
?Pristolepidinarum P. jaegeri Nag Otolith A possible pristolepid otolith.
Serranidarum S. sp. Anjar Otolith A serranid otolith.

Amphibians

Genus Species Location Stratigraphic position Material Notes Images
Gobiatidae incertae sedis Naskal A gobiatid frog.
"Hemisotidae"/"Leptodactylidae" incertae sedis Naskal A frog of uncertain affinities.
Indobatrachus I. pusillus Worli Hill Early Paleocene Multiple complete skeletons A frog of uncertain affinities.
Pelobatidae incertae sedis Nagpur A pelobatid frog.
Ranoidea incertae sedis Naskal A ranoid frog.
Costata incertae sedis A costatan frog
?Caudata incertae sedis A possible salamander.

Reptiles

Turtles

Genus Species Location Stratigraphic position Material Notes Images
Carteremys C. leithii Worli Hill Early Paleocene Carapace, plastron, skull and partial mandible A turtle of uncertain affinities.
Sankuchemys S. sethnai Amboli Quarry Skull A bothremydid turtle.

Lepidosaurs

Genus Species Location Stratigraphic position Material Notes Images
Acrosphenodontia Incertae sedis Naskal Dentary with teeth. An indeterminate rhynchocephalian.
"Agama" A. sp. Rangapur An indeterminate agamid lizard.
Anguidae Incertae sedis Naskal An indeterminate anguid lizard.
?"Contogenys" ?"C." sp. Nagpur An indeterminate scincomorph lizard.
Deccansaurus D. palaeoindicus Kesavi Maastrichtian/Early Paleocene Jaws & several osteoderms. A scincoid lizard.
?"Exostinus" "E." estestai Nagpur An indeterminate xenosaurid lizard.
"Eumeces" "E." sp. Rangapur An indeterminate scincid lizard.
Indophis I. sahnii Naskal Over 160 vertebrae. A nigerophiid snake.
"Litakis" "L." sp. Nagpur An indeterminate lizard.
"Pristiguana" "P." sp. Nagpur An indeterminate iguanid lizard.
Serpentes Incertae sedis Naskal A trunk vertebra & left dentary. A snake.
Serpentes Incertae sedis Possibly a primitive form,
Madtsoiidae Incertae sedis Three individuals. Madsoid snakes.
cf. Indophis cf. I. sahnii Nigerophiidae snake.
Booidea Incertae sedis Possibly a Booid snake.

Crocodyliforms

Genus Species Location Stratigraphic position Material Notes Images
Crocodylidae incertae sedis Worli Hill Teeth and dentary. A crocodylid crocodyliform.
Dyrosauridae incertae sedis Kisalpuri Partial mandible, frontal, and vertebrae A dyrosaurid crocodyliform.
Crocodyliformes incertae sedis Naskal Teeth. Shows similarities to Hamadasuchus and perhaps Mahajangasuchus.

Dinosaurs

Genus Species Location Stratigraphic position Material Notes Images
?"Hypselosaurus" "H." sp Mohgaon Kalan A titanosaurian sauropod.
Massospondylus M. rawesi Tooth Previously thought to be Massospondylus now thought to have been an indeterminate Theropod.
Sauropoda Incertae sedis Asifabad, Ranipur, Anjar
  • Bones.
  • Anjar specimen consists of tibia, fibula, radius, ulna, femur, scapula, claws, ribs and vertebrae, remains are fragile but well-preserved.
 Indeterminate sauropods.
Oogenera
Genus Species Location Stratigraphic position Material Notes Images
Megaloolithus baghensis Kisalpuri Eggshell fragments A Titanosaur egg.
Subtiliolithus kachhensis Kisalpuri Eggshell fragments A Enantiornithine bird egg.

Pterosaurs

Genus Species Location Stratigraphic position Material Notes Images
Pterosauria incertae sedis Sirol-khal locality An indeterminate dentulous pterosaur. May not be from the Maastrichtian.

Mammals

Genus Species Location Stratigraphic position Material Notes Images
Bharattherium B. bonapartei Kisalpuri A fragmentary cheek-tooth. A sudamericid mammal.
Deccanolestes D. hislopi Naskal microvertebrate site Molars, calcanea, astralgi, humerus, ulna. A eutherian mammal.
D. robustus Naskal microvertebrate site "Dental material and an astragalus". A eutherian mammal.
D. narmadensis Kisalpuri "Isolated rear molar." A eutherian mammal.
Indoclemensia I. naskalensis Naskal microvertebrate site Right second Molar. A eutherian mammal.
I. magnus Naskal microvertebrate site Left second Molar. A eutherian mammal.
Indotriconodon I. magnus Kutch Single lower Molar. A eutriconodont mammal.
Kharmerungulatum K. vanvaleni Kisalpuri Isolated right lower molar. A eutherian mammal.
Sahnitherium S. rangapurensis Rangapur microvertebrate site Upper Molar. A eutherian mammal.

Arthropods

GenusSpeciesMaterialLocationTime PeriodNotesImages
?Buprestidae Indeterminate Maharashtra Maastrichtian A Jewel beetle.
Lomatus L. hislopi Maharashtra Maastrichtian A Jewel beetle.
?Curculionidae Indeterminate Maharashtra Maastrichtian A Snout beetle.
Meristos M. hunteri Maharashtra Maastrichtian A Snout beetle.
Ostracoda Indeterminate Maharashtra Maastrichtian An Ostracod.
Palaeotanymecides P. hislopi Maharashtra Maastrichtian A Snout beetle.

Mollusca

Genus Species Location Stratigraphic position Material Notes Images
Bamanboria B. oblongis Bamanbor Early Eocene Shells A deccanoid freshwater mussel.
Chotilia C. deccanensis Bamanbor Early Eocene Shells A deccanoid freshwater mussel.
C. trappeansis
C. tuberculata
Deccanoida D. aleta Bamanbor Early Eocene Shells A deccanoid freshwater mussel.
D. congruis
D. costaria
Limnaea sp. Maharashtra Maastrichtian A snail.
Valvata sp. Maharashtra Maastrichtian A snail.
Paludina sp. Maharashtra Maastrichtian A snail.
Physa P. prinsepii Maharashtra Maastrichtian A snail.

Flora

Genus Species Location Stratigraphic position Material Notes Images
Cocos C. binoriensis A coconut palm tree
Connaroxylon C. dimorphum Dhagaon, Mandla district Wood Affinities with Connaraceae.
Euphorbiotheca E. deccanensis Fruit, member of Euphorbiaceae.
Chara C. chhindwaraensis Algae, Member of Characeae.
Microchara M. shivarudrappai Algae, Member of Characeae.
Platychara P. closasi Algae, Member of Characeae.
Hyphaeneocarpon Fruit, member of palm tribe Borasseae.
Indovitis I. chitaleyae Member of Vitaceae.
Elodeophyllum E. deccanii Member of Hydrocharitaceae.
Sabalites S. dindoriensis Member of Coryphoideae.
S. karondiensis
S. ghughuaensis
S. umariaensis
Malvacipolloides M. deccanensis Member of Malvaceae.
M. intertrappea
Palmocarpon Fruit, member of palm tribe Cocoseae.
Palmoxylon P. calamoides Wood, member of palm tribe Trachycarpeae.
P. caryoteaeoides
P. ceroxyloides
P. coryphaoides
P. dindoriensis
P. nannorrhopsoides
P. sabaleaeoides
P. trachycarpeaeense
Cryosophiloxylon C. indicum Member of Cryosophileae.
Elioxylon E. seoniensis Member of Achariaceae and Salicaceae.
Baccatocarpon B. mohgaoensis Fruit
Phoenicites P. deccansis Member of Arecaceae.
Pantocarpon Fruit, member of Torricelliaceae.
Dipterocarpus D. dindoriensis Member of Dipterocarpaceae.
Phyllanthocarpon P. singpurensis Fruit, member of Phyllanthaceae.
Ochnaceoxylon O. tertiera Member of Ochnaceae.
Spinopinnophyllum S. acanthorachis Member of Arecaceae.
Portulacaceocarpon P. bhuterensis Fruit, member of Portulacaceae.
Rhizopalamoxylon R. arecoides Palm rhizome, close affinities to Nypa.
R. nypoides
Pediastrum Algae.
Lecaniella Algae.
Pierceites P. deccanensis A Dinocyst.
Aulacoseira A Diatom.
Azolla Member of Salviniaceae.
Palaeosinomenium P. indicum Member of Menispermaceae.
Crybelosporites Member of Marsileaceae.
Sparganiaceaepollenites Pollen grains, Member of Sparganiaceae/Typhaceae.
Marsilea M. patnii Member Marsileaceae.
Orthogonospermum O. patanense Member of Zingiberaceae.
Regnellidium Member of Marsileaceae.
Nymphaeaceae indet.
Typhaceae indet.
Liliaceae indet.
Kapgateophyllum K. sp. Member of Acanthaceae.
Farabeipollis P. deccanensis Pollen.
Pontederiaceae indet.
Ovoidites Member of Zygnemataceae.
Gabonisporis Pollen grains, member of Marsileaceae.

See also