IIT JAM 2024 SOLUTION

Out of the three plate tectonic settings,
1. convergent/ destructive : causes denser plate subduction that plate creates a zone of deep focused earthquake known as Benioff Wadati zone with reverse faulting. Ex – ring of fire
2. divergent/ constructive : causes plates breaking apart causing magma comes out and new crust forms with shallow focused earthquakes with normal faulting. Ex – mid atlantic ridges
3. conservative : pates moving apart from earth other causing a strike slip faulting. Ex – San-Andrews fault.

1) In beta minus (β−) decay, a neutron is converted to a proton, and the process creates an electron and an electron antineutrino; while in beta plus (β+) decay, a proton is converted to a neutron and the process creates a positron and an electron neutrino. β+ decay is also known as positron emission.

2) Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or “decays” into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

3) Electron capture is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. This process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino.

1. Intergranular Texture : here crystal occupies the angular space between the larger crystals.
2. Blasto-porphyritic Texture : it is original porphyritic texture of igneous rock still preserved after metamorphism.
3. Graphic Texture : occurs by simultaneous crystallization of phases [quartz and feldspar in granite].
4. Rapakivi Texture : when crystals of orthoclase specially sanidine surrounded by the plagioclase called the rapakivi texture.

Metamorphic facies assemblages

1. The gondwana rocks have been exposed in various area. One area have Raniganj formation with Glossopteris leaf fossil.
2. Another gondwana rock exposed in Satpura-Gondwana basin. It has Bagra, Degana, Motour etc. formations with Bagra with algal remains.
3. Bagh and Lametas are cretaceous formation. It has Dinosaur fossils
4. Nimar Sandstone is a part of Bagh beds which is also Cretaceous age. It occurs along the Narmada valley.

1. Law of superposition states that the rocks are deposited one over the other where oldest at the bottom and youngest at the top.
2. Law of uniformitarianism states that the processes on the Earth happening today the same way happened in the past.
3. The faunal succession states that species changes through time in the unidirectional manner each form is unique that come before and after.
4. The original horizontality states that the rocks have been deposited originally as horizontal layer. The are deformed or tilted later on.

Dropstones – These are important indicator of glacial environment. at the end of glacial age the ice melts and floats in the water of ocean when these ice bodies completely melts the rock fragments within them [due to glacial activity] drops to the ocean floor. Such foreign material or rocks are called dropstones. Talchir formation is one of the best example that marks an end of glacial phase.

1. Trough cross bedding is formed by unidirectional flow in which the ripples overlaps to the lower ripple and creates such a bedding. Ex- rivers have unidirectional flow that creates trough cross bedding.
2. Oscillation ripples are formed by the oscillatory motion like incoming and outgoing water is completely opposite. This creates symmetrical ripples. Ex – ocean waves coming perpendicular to the coast and going away perpendicular to the coast.
3. Concretion is a mineral matter that is imbedded within a rock layer and sometimes confused as a fossil egg.
4. Hummocky cross-stratification is formed due to storm activity, when a sudden force of water come it creates a mound and associated depression of sediments that forms Hummocky stratification and swaley stratification.

The term precursor means something that comes before another. Kerogen is a precursor to the petroleum.
Sporinite is a maceral that is found in coal.
Clarain is a coal lithotype that is consists of bright and dark color bends. bright bends are composed of maceral vitrinite while dark bend is consists of maceral exinite and inertinite

1. Citrine is the yellow variety of quartz
2. Agate is the banded variety of chalcedony that is cryptocrystalline variety of quartz
3. opal is the hydrated amorphous variety of silica. It contains usually 6 – 10 weight % of water.

ELEMENT ABUNDANCE IN CRUST : O, Si, Al, Fe, Ca, Na, Mg, K …….
ELEMENT ABUNDANCE IN UNIVERSE : H, he …..
ELEMENT ABUNDANCE IN SOLAR SYSTEM : H > He > O > Fe
ELEMENT ABUNDANCE IN ATMOSPHERE : N2, O2, AR, CO2, Ne, He, CH4 …..

ORTHOCERATITIC : rounded saddle and lobes
GONIATITIC : rounded saddle and pointed lobes
CERATITIC : rounded saddles and crenulated lobes
AMONITIC : crenulated saddles and lobes

Body fossils are those which gives us information about the body of organisms. Ex- mold and cast
Coprolites are the fossilised faeces of animals.
Foot prints shows the movement of the animal.
Stromatolites are layered mounds, columns, and sheet-like sedimentary rocks. They were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe

The dissepiments are thin, blister-like layers of coral skeleton which form between the corallites and are structurally similar to the sterome.
In Brachiopoda the pedicle opening is more triangular in shape instead of round, it is called a delthyrium.
In Trilobites the tail (pygidium) margin is posterior and the head (cephalon) margin anterior, in between there is thorex.
In Echnoidea Ambulacrum is an elongated area of the shell of an echinoderm in which a row of tube feet are arranged.The area on the shell between ambulacra is known as an interambulacrum.

1. Stylolite is a secondary (chemical) sedimentary structure consisting of small toothlike shape. It is common in limestone, marble.
2. Load structures are a type of soft-sediment deformation structure comprising synforms (load casts and pseudonodules) and antiforms (flame structures and diapirs) at an interface.
3. The current scours form when current flows through an obstacle on the bed (particle, shells etc.). The form of the crescent reflects the pattern of flow around the obstacle.
4. The term stromatolite means layered rocks, which are formed by microorganisms like cyanobacteria.

1. Glacial features : Cirque, horn, tarn, carg and tail, eskers, peternoster lake, U shaped valley etc.
2. Beach features : spit, berm, hooked spit, lagoon, fijords, esturies, bay etc.
3. Aeolian features : Dreikanter, blowout, hamada, yardang etc.
4. Fluvial features : natural levee, flood plain, nick point, point bar, crevasses splay etc.

Darcy law states that (Q) = KIA, with unit as cubic meter / sec.

where, Q = flow rate,
A = cross section area
I = hydraulic gradient

As per the unit, ground water flow is per unit time

Strahler Number [river branching]

click on the link for detailed explanation

In the case of horizontal and vertical beds the bedding plane is either horizontal or vertical which does not creates slipping while in case of inclined beds slipping is possible.

This question needs a practice of structural mapping and cross section analysis.

PEDIONS – A pedion is an open, one faced form. Pedions are the only forms that occur in the Pedial class (1).
PINACOIDS – A Pinacoid is an open 2-faced form made up of two parallel faces.
DOMES – Domes are 2- faced open forms where the 2 faces are related to one another by a mirror plane.
PRISMS – A prism is an open form consisting of three or more parallel faces. Depending on the symmetry, several different kinds of prisms are possible.
PYRAMIDS – A pyramid is a 3, 4, 6, 8 or 12 faced open form where all faces in the form meet, or could meet if extended, at a point.

Here the brackets are fixed. A particular type of bracket is denoted for line, face etc…

stratigraphy older to younger –
Western Dharwar – [sargur group – bababhudan – chitradurga – younger granite]
Eastern Dharwar – [older gneisses – yashvantnagar formation – kolar group – younger granite]
Aravalli craton – The Banded Gneissic Complex of central Rajasthan, the only gneissic basement in India underlie an early Precambrian sediments unconformably
Singhbhum Craton – [archaean granite/ bonai granite phase I – iron ore group – bonai granite kphase II – darging group – gangpur group]

High P/T series – The facies sequence is (Zeolite) – (Prehnite-pumpellyite) – blueschist facies – eclogite facies.
Medium P/T series – (prehnite-pumpellyite facies) – greenschist – amphibolite facies – (granulite facies)
Low P/T series – (zeolie facies) – albite-epidote hornfels facies – hornblende-hornfels facies– pyroxene-hornfels facies – sanidinite facies

Metamorphic facies series Click on the link for complete article

1. Nickel mineralization most commonly occurs in sulphide form in matic-ultramatic rocks
2. About 70% of all continental or terrestrial nickel resources are contained in laterites.
3. Manganese nodules are authigenic deposits composed principally of manganese oxides enriched in Fe and Co, Ni, and Cu. They occur in all the world’s oceans.
4. Ni is very minor in the Skarns deposits.

1. alkali basalts were mainly formed by small-degree melting (<5% by weight) of mantle at high pressure (>3GPa), whereas tholeiitic basalts were derived from larger degrees of melting at shallow depths.
2. CO2 and H2O depress the melting point of mantle peridotites.

Siwalik group contains important vertebrate fossils of Neogene age out of which Proboscidea [elephant], Giraffidae [girraffe] and equadae [horse] are important. Dianosuria is not part of siwalik

1. Uttatur – Trichinopoly – Ariyalur – Niniyur [cretaceous of trichinopoly]
2. Patcham – Chari – Katrol – Umia [ jurassic of kutch]
3. Kamaliyal – Chinji – Nagri – Dhokpathan – Tatrol -Pinjor [siwaliks]
4. Semri – Kaimur – Rewa – Bhander [ Vindhyans]

1. Biogenic carbonates are formed by biological activities that needs sunlight which is available in the photic zone.
2. Delta deposits move towards the ocean and hence progradational in nature. They are also coarsening upward sequence.
3. Sabkha is a coastal or inland areas where evaporation exceeds and hence evaporites are deposited.
4. Overwash is the flow of water and sediment over a coastal dune or beach crest during storm events.
5. Self break is a point in the ocean relief where slope changes abruptly resulting in the formation of submarine fans.

High drainage density can be developed with multiple reasons like high relief, when relief is high there are multiple drainage channels causing the high drainage density. and impermeable rocks force them to flow on the surface and maintain the density high.

The arid climate will evaporate the water and leads to the low density. The permeable rocks will allow water to percolate and reduce the surface flow hence low drainage density.

Mass wasting process is the movement of earth material from the high land area to low land areas.

1. Landslides is the movement of rock material down the hill
2. A lahar is a hot or cold mixture of water and rock fragments that flow quickly down the slopes of a volcano.
3. Avalanch is large mass of snow and other material suddenly and quickly tumbling down a mountain.
4. Sand storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface.

The general formula of pyroxene is XYSi2O6, where X and Y are either both divalent cations (mainly Ca, Fe, Mg), or mono- (Na, Li) and trivalent cations (Al, Fe) respectively.

1. Pressure solution takes place when some aqueous fluid flow is around the grains under high pressure conditions.
2. Plumose structures are aggregates of marks radiate from the point where the joint originated and fan outward from a generally straight, rarely curved axial line, then resembling the shape and imprint of a feather.
3. Layered parallel compression causes the buckle folding.
4. cohesion loss causes cataclasites while slickensides are developed due to faulting when strong sliding takes place.

The barrovian sequence is : chlorite zone – biotite zone – garnet zone – staurolite zone – kyanite zone – sillimanite zone

It is batter to remember the table of the following image :