Your Answer : (Not Answered)

Correct Answer : C

The Eocene-Oligocene index foraminifer is Lepidocycilina (Lepidocyclina).

Lepidocyclina is a large benthic foraminifer that appeared in the late Middle to Late Eocene and flourished through the Oligocene into the Miocene, making it a standard index fossil for those carbonate successions, including those of western India.

Miogypsinids range from the Oligocene into the Miocene and are used mainly for the Miocene, Globotruncanella is a Late Cretaceous planktic form, and fusulinids are Carboniferous to Permian, so none of them indexes the Eocene and Oligocene.

Your Answer : (Not Answered)

Correct Answer : B

They are known as the Purana basins.

The Mesoproterozoic to Neoproterozoic sedimentary basins of Peninsular India, such as the Cuddapah, Vindhyan, Kaladgi, Bhima, Chhattisgarh and Indravati basins, hold thick, little-deformed, largely unmetamorphosed sediments. They were grouped as the 'Purana' (old) basins, lying between the Archaean basement and the Phanerozoic cover.

Dharwar refers to the Archaean craton and its schist belts, which are older. The Indo-Gangetic plains (spelt 'plans' in the paper) are Quaternary alluvium. The Siwaliks are Neogene to Quaternary molasse deposits of the Himalayan foothills.

Your Answer : (Not Answered)

Correct Answer : A

The schist belt outside the Dharwar craton is the Sonakhan schist belt.

Sonakhan lies in Chhattisgarh, in the Bastar craton, where it forms a greenstone belt of volcanic and sedimentary rocks.

Holenarasipur is one of the older (Sargur) schist belts of the western Dharwar craton, Sandur is a Dharwar greenstone belt with iron and manganese ores in Ballari district, and the Wayanad schist belt lies at the southern edge of the Dharwar craton in Kerala and Karnataka.

Your Answer : (Not Answered)

Correct Answer : D

The one that is not a craton is the Eastern ghats.

The Eastern Ghats belt is a Proterozoic mobile belt of granulites, khondalites and charnockites along India's east coast, formed by orogeny at the margins of older blocks. It is the classic example of a mobile belt rather than a stable nucleus.

Singhbhum, Dharwar and Bastar (with Aravalli-Bundelkhand) are the Archaean cratons of Peninsular India, old stable blocks of granite-gneiss and greenstone that the mobile belts wrap around.

Your Answer : (Not Answered)

Correct Answer : B

The transition is known as the Fermor Line.

In the Dharwar craton the grade of metamorphism rises from north to south, from greenschist and amphibolite facies rocks to the charnockites of the granulite facies. L.L. Fermor mapped the boundary in 1936, and the orthopyroxene isograd along which charnockite appears, running roughly east-west across southern Karnataka, became known as the Fermor Line.

The Moyar-Bhavani, Palghat-Cauvery and Achankovil shear zones are tectonic shear belts in the Southern Granulite Terrain further south, not the north-south facies transition.

Your Answer : (Not Answered)

Correct Answer : B

The stage boundary marked in a speleothem is the base of the Meghalayan stage.

The Meghalayan, the latest stage of the Holocene, begins at 4,200 years before 2000 CE with an abrupt drying event. Its GSSP, ratified in 2018, is defined in a stalagmite from Mawmluh Cave in Meghalaya, India, the first GSSP placed in a speleothem.

The Northgrippian GSSP is in the NorthGRIP ice core from Greenland, while the Gelasian and Zanclean GSSPs are in marine sedimentary sections in Sicily, so none of them is in a cave deposit.

Your Answer : (Not Answered)

Correct Answer : A

The dental formula is 3 I/i, 1 C/c, 4 P/p and 3 M/m.

The earliest horses, such as Hyracotherium (Eohippus) of the Eocene, kept the full primitive placental formula: 3 incisors, 1 canine, 4 premolars and 3 molars in each half of each jaw, 44 teeth in all. Later horses reduced the first premolar and lost or reduced the canine in females, while the cheek teeth became high-crowned for grazing.

The other options give 3 or 4 canines, which no mammal has; the canine count is always at most one per half-jaw. They also give only 1 molar or 1 premolar, which does not fit an animal that needs a row of grinding cheek teeth.

Your Answer : (Not Answered)

Correct Answer : C

The key's answer is Feeding.

In Seilacher's behavioural classification of trace fossils, fodinichnia (written 'Fodichnia' in the paper) are feeding traces: burrows made by deposit-feeders that mine the sediment for food while staying in one place, often producing U-shaped or radiating spreite structures.

The other strategies have their own categories. Escape traces are fugichnia (the paper's 'Escoping'), crawling traces are repichnia, and grazing traces made at the sediment surface are pascichnia. Since fodinichnia record feeding within the sediment, the general answer is feeding.

Your Answer : (Not Answered)

Correct Answer : C

The feeding body of a bryozoan is the Polypide.

Each bryozoan zooid has two parts. The polypide is the soft feeding part: the tentacle crown (lophophore), which filters food from the water, with the U-shaped gut and associated muscles. It can be withdrawn into the second part, the cystid.

The cystid is the body wall with its skeleton that houses the polypide, the coelom is the internal body cavity, and the operculum is the lid that closes the orifice in many cheilostomes when the polypide is withdrawn.

Your Answer : (Not Answered)

Correct Answer : B

The brachiopod with a straight hinge line is Spirifer.

Spirifer is a strophic brachiopod: the hinge line is long and straight, often the widest part of the shell, giving it a winged outline. It belongs to the Spiriferida, which carry spiral brachidia, and it is common in Carboniferous rocks.

Terebratula and Gryphus are terebratulids with a short, curved (astrophic) hinge, and Lingula is an inarticulate brachiopod with no teeth and sockets, so no hinge line at all.

Your Answer : (Not Answered)

Correct Answer : A

The sponge with siliceous spicules is Euplectella.

Euplectella, Venus's flower basket, is the textbook hexactinellid or glass sponge. Its skeleton is made of six-rayed spicules of hydrated silica (opal, polymerised silicic acid) fused into a lattice.

Sycon and Leucosolenia are the standard examples of calcareous sponges (class Calcarea), whose spicules are calcium carbonate, so they are wrong. The fourth option is not one of the standard textbook examples of a siliceous sponge, and the key gives the glass sponge.

Your Answer : (Not Answered)

Correct Answer : D

The Permian-Triassic unit is the Guryul ravine section (spelt 'Guruyul ravines' in the paper).

The Guryul ravine near Srinagar in Kashmir exposes a continuous marine succession across the Permian-Triassic boundary, from the Zewan Formation (Permian) to the Khunamuh Formation (Permian to Triassic). It is one of the world's reference sections for the end-Permian mass extinction.

The Haimanta Group of the Tethys Himalaya is late Precambrian to Cambrian. The Muth Formation is a Silurian to Devonian quartzite of the Spiti region. The Kali Formation is not the unit cited for this boundary. Only Guryul spans the Permian-Triassic.

Your Answer : (Not Answered)

Correct Answer : B

The keyed answer is the Vaikrita system.

In his work on the Central Himalaya of Kumaon and Garhwal, Griesbach grouped the ancient, highly folded crystalline schists and related metamorphic rocks under the name Vaikrita system; in the standard Indian stratigraphy texts this is the name given to that sequence in the Kumaon-Garhwal region.

The Haimanta system is the overlying sequence of unfossiliferous Cambrian slates and quartzites, best known from Spiti. The Jutogh series belongs to the Simla area of Himachal Pradesh, and the Salkhalas are the old metamorphic rocks of Kashmir.

Your Answer : (Not Answered)

Correct Answer : A

The correct match is a-R, b-P, c-T, d-S.

• Badami Group - Kaladgi basin, Karnataka (it overlies the Kaladgi Supergroup).
• Kheinjua Formation - Vindhyan basin (part of the Semri Group).
• Sullavai Group - Pranahita-Godavari valley.
• Papaghni Group - Cuddapah basin (its lowest group).

The other codes assign the Kheinjua Formation to Chhattisgarh or the Pranahita-Godavari valley, or the Papaghni Group outside the Cuddapah basin, which do not fit.

Your Answer : (Not Answered)

Correct Answer : B

Animals of the deep-sea environment show little evolutionary change.

The deep sea is cold, dark, high in pressure and very stable over long periods of time. With little environmental change to drive selection, many deep-sea lineages have changed slowly, and several 'living fossils', such as stalked crinoids and monoplacophorans, survive there.

Coral reefs, rocky intertidal zones and lagoons are shallow, variable environments subject to changes in sea level, temperature and salinity. Their faunas have turned over and diversified repeatedly through geological time.

Your Answer : (Not Answered)

Correct Answer : C

The numbering reads 1 interambulacrum, 2 ambulacrum, 3 genital plate, 4 ocular plate, 5 aboral pole (option C).

• Arrow 1 spans one of the five wide columns of large plates carrying the ringed tubercles that hold the spines: an interambulacrum.
• Arrow 2 points at a narrow band between those columns, marked by paired pores for the tube feet: an ambulacrum.
• Arrow 3 points at a large plate in the ring around the apical system, in line with an interambulacrum: a genital plate, the kind that carries a gonopore.
• Arrow 4 points at a small plate at the outer end of an ambulacrum: an ocular plate, which has the pore for the terminal tentacle.
• Arrow 5 points at the centre of the apical system, where the small plates surround the periproct: the aboral pole.

Option A reverses both pairs (ambulacrum with interambulacrum, ocular with genital plate), option B reverses only ambulacrum and interambulacrum, and option D puts the genital plate at the centre and the aboral pole at arrow 3, so none of them fits the drawing. The University's key is C.

Your Answer : (Not Answered)

Correct Answer : B

The group not in correct sequence is Devonian, Ordovician, Silurian, Permian.

The Palaeozoic periods run Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian. Putting the Devonian before the Ordovician and the Silurian reverses the order, so this group is wrong.

The other groups are correct: the Palaeogene and Neogene epochs run Palaeocene, Eocene, Oligocene, Miocene; the eras run Palaeozoic, Mesozoic, Cenozoic; and the Mesozoic periods run Triassic, Jurassic, Cretaceous.

Your Answer : (Not Answered)

Correct Answer : A

The key's answer is that Vindhyan rocks are thickest along the southern margin of the supergroup, which is a faulted contact.

The Vindhyan basin of central India is bounded on the south by the Son-Narmada lineament, a deep fault zone. The basin subsided most along this margin, so the sedimentary pile is thickest there, in the Son valley sector, where it reaches several kilometres, and it thins northwards onto the Bundelkhand massif.

So the rocks are not thickest near the Bundelkhand massif, nor uniformly along the axis, and the large variation in thickness rules out the statement that there is none.

Your Answer : (Not Answered)

Correct Answer : B

The K-Pg boundary is defined globally by the presence of an iridium anomaly in sediments.

The Global Boundary Stratotype Section and Point for the base of the Paleogene (Danian) is at El Kef, Tunisia, placed at the base of the boundary clay, whose iridium spike records the Chicxulub impact. The same thin iridium-rich layer has been found in marine and land sections worldwide, which makes it a global marker.

The absence of dinosaur fossils is negative evidence: fossils are rare, so the last bone found usually lies below the true extinction level. Mercury enrichment has been linked to Deccan volcanism, but it is spread over an interval and is not the defining marker. Deccan volcanism continued into the Paleocene, so its end does not coincide with the boundary.

Your Answer : (Not Answered)

Correct Answer : B

The segment representing an unconformity is Q.

In a graphic correlation plot, each point on the line pairs a level in S2 with the level of the same biostratigraphic horizon in S1, and the slope of a segment compares how much rock the same time interval left in each section. Along Q the line is horizontal: the S2 thickness keeps increasing while the S1 level does not change at all. So a time interval represented by tens of metres of strata in S2 is represented by no strata in S1, which is a hiatus, an unconformity in S1.

Segments P, R and S all slope, so both sections were accumulating sediment during those intervals; a steep or gentle slope only means S1 accumulated faster or slower than S2, not that time is missing.