Unconformity

SUBMITTED TO :- SUBMITTED BY:-
Dr. Sanjay Tignath sir Mayank Mahawar
M.Sc. 1ST SEM
ROLL NO:-12

 An unconformity is a depositional contact
between two rocks of measurably ages.
 An unconformity is a surface of erosion that
separates the younger strata from older rocks.
 It is one of the most common geological feature
found in rocks or in succession.
 Unconformities represent gaps in
the geologic record; periods of time that are not
represented by any rocks.
 Unconformities are resulted due to tectonic
activity in form of uplift or subsidence of land.

Angular unconformity
 Non conformity
Disconformity
Local unconformity

 An angular unconformity is an erosional surface and
separates an older sequence of rocks, in which bedding is
inclined to the unconformity, from a younger sequence in
which bedding is essentially parallel to the unconformity.
 The term “angular” expresses the fact that layers above
and below angular unconformities are not parallel.
ANGULAR UNCONFORMITY :-

Angular Unconformity: San Lorenzo Canyon area,

 Non conformity are depositonal surface which
separating younger sedimentary or volcanic
rocks from underlying older crystalline
rocks(metamorphic rock or igneous rock).
 They usually indicate that a long period of
erosion occurred prior to deposition of the
sediments

Grand Canyon,Arizona; sandstone (cambrian)
overlies schist (Proterozoic )

DISCONFORMITY :-
 It is also known as parallel unconformity.
 A disconformity separates two sequences, both of
which are bedded parallel to the unconformity.

Kane County, Utah , United States

 Also known as non-depositional unconformity.
 It is similar to a disconformity but local in extent
and represents a short period of non-deposition.
 The age difference between the overlying and
underlying beds is very less.
 This is generally found in flood affected areas
representing short time gaps.

 Difference in structure
 Difference observation
 Difference in fossil record
 Presence of conglomarate
 Difference in environmental of deposition

 An outline of structural geology –PAUL F.
WILLIAMS
 Structural Geology – M.P. BILLINGS
 Structural Geology of rocks and regions –
GEORGE H. DAVIS

Unconformity

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