Home > Terms > English (EN) > unconformity


A surface that represents a break in the geologic record, with the rock unit immediately above it being considerably younger than the rock beneath. There are three major aspects to consider:

  1. Time. An unconformity develops during a period of time in which no sediment is deposited. This concept equates deposition and time, and an unconformity represents unrecorded time.
  2. Deposition. Any interruption of deposition, whether large or small in extent, is an unconformity. This aspect of unconformity pre-supposes a standard ‘scale’ of deposition which is complete. Major breaks in sedimentation can usually be demonstrated easily, but minor breaks may go unrecorded until highly detailed investigations are made.
  3. Structure. Structurally, unconformity may be regarded as planar structures separating older rocks below from younger rocks above, representing the ‘break’ as defined in (1) and (2) above. A plane of unconformity may be a surface of weathering, Erosion or denudation, or a surface of non-deposition, or possibly some combination of these factors. It may be parallel to the upper strata, make an angle with the upper strata, or be irregular. Subsequent Earth movements may have folded or faulted it.
Collect to Blossary

Member comments

You have to log in to post to discussions.

Terms in the News

Billy Morgan

Sports; Snowboarding

The British snowboarder Billy Morgan has landed the sport’s first ever 1800 quadruple cork. The rider, who represented Great Britain in the 2014 Winter Olympics in Sochi, was in Livigno, Italy, when he achieved the man-oeuvre. It involves flipping four times, while body also spins with five complete rotations on a sideways or downward-facing axis. The trick ...

Marzieh Afkham

Broadcasting & receiving; News

Marzieh Afkham, who is the country’s first foreign ministry spokeswoman, will head a mission in east Asia, the state news agency reported. It is not clear to which country she will be posted as her appointment has yet to be announced officially. Afkham will only be the second female ambassador Iran has had. Under the last shah’s rule, Mehrangiz Dolatshahi, a ...

Weekly Packet

Language; Online services; Slang; Internet

Weekly Packet or "Paquete Semanal" as it is known in Cuba is a term used by Cubans to describe the information that is gathered from the internet outside of Cuba and saved onto hard drives to be transported into Cuba itself. Weekly Packets are then sold to Cuban's without internet access, allowing them to obtain information just days - and sometimes hours - after it ...

Asian Infrastructure Investment Bank (AIIB)

Banking; Investment banking

The Asian Infrastructure Investment Bank (AIIB) is an international financial institution established to address the need in Asia for infrastructure development. According to the Asian Development Bank, Asia needs $800 billion each year for roads, ports, power plants or other infrastructure projects before 2020. Originally proposed by China in 2013, a signing ...


Online services; Internet

Spartan is the codename given to the new Microsoft Windows 10 browser that will replace Microsoft Windows Internet Explorer. The new browser will be built from the ground up and disregard any code from the IE platform. It has a new rendering engine that is built to be compatible with how the web is written today. The name Spartan is named after the ...

Featured Terms

  • 0


  • 58


  • 3


Industry/Domain: Education Category: General education

2. Canada

In Canada, 64.8 percent of women have higher education compared to 63.4 percent of Canadian men. In 2006 and 2007, women made up 57 percent of all ...

Featured blossaries

Haunted Places Around The World

Category: Entertainment   65 10 Terms

International Accounting Standards

Category: Business   3 29 Terms

Browers Terms By Category