unconformity

It echoes James Playfair’s description of the “abyss of time” he glimpsed while viewing a strata unconformity at Siccar Point in 1788, when geology was first emerging as a science.

From The Guardian ● Apr. 20, 2019

This unconformity represents a time where erosive processes took over after millions of years when the lake had finally dried up - to form a new land surface.

From BBC ● Mar. 22, 2018

She’s revising a manuscript describing an unconformity in the sedimentary layers of Mount Sharp, within the Gale crater, a record of the alternating wet-dry cycles on the planet.

From Science Magazine ● Jun. 29, 2017

This is known as the Great Unconformity and is an example of an angular unconformity.

From Textbooks ● Jan. 1, 2017

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.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" by Various

Disconformities are unconformities that occur between parallel layers of strata indicating either a period of no deposition or erosion.

From Textbooks ● Jan. 1, 2017

There are three types of unconformities, nonconformity, disconformity, and angular unconformity.

From Textbooks ● Jan. 1, 2017

Gaps in the geological record are represented by various types of unconformities.

From Textbooks ● Jan. 1, 2015

There are four types of unconformities, as summarized in Table 8.1, and illustrated in Figure 8.9.

From Textbooks ● Jan. 1, 2015

Pre-Cambrian time probably was longer than all later geological time down to the present, as we may infer from the vast thicknesses of its rocks and the unconformities which part them.

From The Elements of Geology by William Harmon Norton