earth sci (long quiz)

• The term rock strata refers to layers of sedimentary rock.
• These horizontal layers form from the processes of weathering, erosion, deposition, compaction, and cementation.
• deposition, Compaction and cementation are the formation of sedimentary rocks
• The law of stratigraphy is a set of laws that's describe the patterns in which rock layers are deposited.
• The law of superposition is one of the principles of geology scientists use to determine the relative ages of rock strata, or layers. This principle states that layers of rock are superimposed, or laid down one on top of another. The oldest rock strata will be on the

  bottom and the youngest at the top.
• the principle of cross-cutting relationships states that the geologic structure that cuts across another structure is younger than

  the structure it cuts across.
• The Law of Original Horizontality suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed. This allows us to infer that something must have happened to the rocks to make them tilted. This includes mountain building events, earthquakes, and faulting.
• There are Three kinds of Unconformities, Disconformities, Nonconformities, Angular Unconformities.
• A disconformity is an unconformity between parallel layers of sedimentary rocks which represents a period of

  erosion or non-deposition. Disconformities are marked by

  features of subaerial erosion. This type of erosion can leave channels and paleosols in the

  rock record.
• A nonconformity is obvious, because crystalline rocks occur below the contact. Some Features Used to Identify Unconformities: (a) Scour Channels in Sediments, (B) Basal Conglomerate, (C) Age Discordance

  From Fossil Evidence, and (D) Soil

  Horizon or Paleosol
• Correlation is the process used by geologists (or stratigraphers) to "match" rock layers and formations of one outcrop to rock layers and formations of another outcrop that are of similar age. Correlation is done by matching rock layers by rock type, grain size, the presence of fossils and other distinctive features.