Clock in Rocks JIAN

Determining age or chronology of events in the history of Earth

Placing rocks in proper sequence of formation without exact time

Specify numerical ages of geologic events

In an undisturbed sequence of strata, each layer (bed) is younger than the layer below and older than the layer above.

Sediments forming stata are originally deposited horizontally.Therefore, any tilted strata must have been horizontal prior to its tilting.

Sediments (therefore strata) are deposited laterally and continuously in all directions unless (1) sediment supply runs out, (2) is impeded by an obstacle, or (3) meets along the edge of the depositional basin.

If one geologic feature cuts across another, the feature that has been cut is older. Conversely, All geologic structure that cuts across another is younger.

Rock containing inclusions (fragment of another rock) must be younger than the inclusion;

are always older than the rocks that contain them.

Fossils contained in rocks succeed each other vertically in a specific, reliable order that can be indentified over wide distances.