The Intertrappean Beds are a

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

and early

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

geologic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize ...

in India. These

beds A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...

are found as interbeds between

Deccan Traps The Deccan Traps are a large igneous province of west-central India (17–24°N, 73–74°E). They are one of the largest volcanic features on Earth, taking the form of a large shield volcano. They consist of many layers of solidified flood ...

layers, including the slightly older

Lameta Formation The Lameta Formation, also known as the Infratrappean Beds (not to be confused with the contemporaneous Intertrappean Beds), is a sedimentary geological formation found in Madhya Pradesh, Gujarat, Maharashtra, Telangana, and Andhra Pradesh, Indi ...

. They consist a number of different subgroups and formations, and span the

Cretaceous–Paleogene boundary The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end o ...

. Many mostly fragmentary fossils, especially of small vertebrates, are known from the formation. Indeterminate

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

and

pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...

remains have been recovered from the formation, as well as

dinosaur egg Dinosaur eggs are the organic vessels in which a dinosaurs, dinosaur embryo develops. When the first scientifically documented remains of non-avian dinosaurs were being described in England during the 1820s, it was presumed that dinosaurs had la ...

s.Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607. The mammal genera ''

Deccanolestes ''Deccanolestes'' is a scansorial, basal Euarchontan from the Late Cretaceous (Maastrichtian) and Paleocene Intertrappean Beds of Andhra Pradesh, India. It may be closely related to ''Sahnitherium''. ''Deccanolestes'' has been referred to Pala ...

'', ''

Sahnitherium ''Sahnitherium'' is a possible basal Euarchontan from the Maastrichtian of the Intertrappean Beds of Andhra Pradesh, India. It may be closely related to '' Deccanolestes.'' The holotype A holotype (Latin: ''holotypus'') is a single physi ...

'', ''

Bharattherium ''Bharattherium'' is a mammal that lived in India during the Maastrichtian (latest Cretaceous) and possibly the Paleocene. The genus has a single species, ''Bharattherium bonapartei''. It is part of the gondwanathere family Sudamericidae, which is ...

'', '' Indoclemensia,

Indotriconodon ''Indotriconodon magnus'' is an extinct mammal from the Late Cretaceous of India. A eutriconodont, it represents the geologically youngest of the group dating to the Maastrichtian just a few thousand years before the KT event (a record previousl ...

'' and''

Kharmerungulatum Kharmerungulatum is an extinct genus of herbivorous mammal from the Late Cretaceous (Maastrichtian) Intertrappean Beds of Madhya Pradesh, India. Its specific epithet honors Leigh Van Valen. It was described as one of the earliest known condylarth ...

'' have been recovered from several localities. The

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

-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 The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretac ...

, ~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

, ~64.5 mya - unknown) Mittal ''et al'' (2021) divided the group into the following provinces: * Western Ghats-Central Indian Volcanic Province (WVP) (age: Late

) * Saurhastra-Kutchh Province (age: ?

early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

) * 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 The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

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

Fish

Otolith-based taxa

Amphibians

Reptiles

Turtles

Lepidosaurs

Crocodyliforms

Dinosaurs

= Oogenera

Pterosaurs

Mammals

Arthropods

Mollusca

Flora

Footnotes

References

* Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. {{ISBN, 0-520-24209-2. Geologic formations of India Maastrichtian Stage Danian Stage Cretaceous–Paleogene boundary Ooliferous formations