Question

4. Identify the unconformities below by the letter of the alphabet in the figure as well as what type of unconformity (angular, disconformity, non-conformity). hoon9002 i alqining 12501 no mortizovete si todo Key: Iis Shale sed Dis Siltstone sed His Sandstone --- Fis Fossiliferous timestone/H A is made of Limestone 1 Cis Shale- Gis Granite 19 nCOUS sto s eisvel antrell zysz stalanta Hatrice S ars and Nonconformity between layers Disconformity between layers _ _and_ tilted : Angular unconformity at points_E__and B ortolans

Some explanations would be really helpful. Thanks.

Answer 1

Nonconformity is defined as a type of unconformity in which a older igneous or metamorphic rock body is underlain by much younger sedimentary bodies. Here G is granite, which is underlain by shale(C). So we can say that nonconformity is between layers G and C.

Disconformity is another type of unconformity in which parallel sedimentary beds shows a period of non-deposition or erosion. The carbonate rich beds of limestone and fossiliferous limestone is seperated from sandstone by a thin disconformity. So we can say that disconformity is between layers H and A/F. We say A/ F both because due to faulting, fossiliferous limestone (F) may be eroded at some place during the period of non-deposition , and the underlying Limestone(A) is exposed above which the disconformity occured.

Angular unconformity is at point E and B clearly because there is angular contact of sedimentary bodies.