noun
definition
A lack of conformity
definition
A gap in time in rock strata, where erosion occurs while deposition slows or stops
Examples of unconformity in a Sentence
A great unconformity separates the Table Mountain and Ecca series.
Its distribution is very different from that of the Upper Cretaceous, and there is a great and widespread unconformity between them.
From the Permian to the Lias the sequence in the central Himalaya shows no sign of a break, nor has any unconformity been proved between the Liassic beds and the overlying Spiti shales, which contain fossils of Middle and Upper Jurassic age.
On the Pacific coast the marine Eocene lies west of the Sierras, and between it and the Cretaceous there is a general, and often a great, unconformity.
No certain representative of the Dingle Beds has been traced elsewhere throughout the south of Ireland, where the Old Red Sandstone succeeds the uptilted Silurian strata with striking unconformity.
A possible basal unconformity has been observed with a fine grained conglomerate lying on the hard Devonian quartzite.
If you turn your back on the interpretative panel the landscape contains the unconformity - with Quinag looming above.
One of the most dramatic features of much of the Torridonian outcrop is the basal unconformity with the Lewisian basement.
All basement reservoirs underlie a regional unconformity and almost all lie on an uplift or high.
Each of these systems is separated from the other by a strong unconformity.
Upon the folded slates and schists which constitute these inliers the Devonian rests with marked unconformity; but north of the ridge of Condroz Ordovician and Silurian beds make their appearance.
In many places in the west they rest on what appear to be Ordovician beds, but without unconformity.
I Silurian (and Cambrian?) "Dalradian" Metamorphic Series .Diorite and allied Basic Rocks '?-t =i=' Granite and allied Acid Rocks montory the conglomerates of this period rest with striking unconformity on the Dingle Beds and Upper Silurian series.
An important geological characteristic of most of the Cordilferan region is that the Carboniferous strata, which in western Europe and the eastern United States contain many coal seams, are represented in the western United States by a marine limestone; and that the important unconformity which in Europe and the eastern United States separates the Palaeozoic and Mesozoic eras does not occur in the western United States, where the formations over a great area follow in conformable sequence from early Palaeozoic through the Mesozoic.
The unconformity between these groups is therefore widespread, probably more so than any later unconformity.
The extent of the unconformity is usually significant of the geographic changes of the interval unrecorded by known Proterozoic rocks.
There is in some places an unconformity between the Richmond beds (or their equivalent) and underlying formations, and this unconformity, together with certain palaeontological considerations, has raised the question whether the uppermost part of the system, as outlined above, should not be classed as Silurian (Upper Silurian).
No unconformity, however, has yet been detected anywhere in the sandstone series, and in the absence of fossils the upper sandstone may represent any period from the Carboniferous to the Cretaceous.
From the absence of any well-marked unconformity it is evident that in the northern part of the Himalayan belt, at least in the Spiti area, there can have been no post-Archaean folding of any magnitude until after the deposition of the Nummulitic beds, and that the folding was completed before the later Tertiaries of Hundes were laid down.
But Professor Park has obtained Jurassic fossils in the Maitai series; so that it will probably be ultimately divided between the Carboniferous and Jurassic. The two systems should, however, be separable by an unconformity, unless the Maitai series also includes representatives of the Kaihiku series (the New Zealand Permian), and of the Wairoa series, which is Triassic.
This unconformity is generally found about the same horizon in the continental Culm areas, and it occurs again in the western part of the English Culm.