Final answer:
The time equivalence of distant or minimal outcrop rock units can be determined by lateral tracing of units, key or marker beds, index fossils, and rock sequences. Each of these methods provides valuable information about the spatial and temporal features of geological formations.
Step-by-step explanation:
The time equivalence of rock units separated by great distances or where outcrop is minimal can indeed be determined by lateral tracing of units, key beds or marker beds, index fossils, and rock sequences.
Lateral tracing involves a systematic search of horizontal rock layers to find those with the highest concentration of fossils. This is a common practice in stratigraphic geology to determine the spatial distribution and timing of sedimentary deposits.
With key beds or marker beds, these are distinctive, widespread, rapidly deposited layers of sediment that serve as markers in time. An example of this could be a volcanic ash layer.
Index fossils are fossils of widely distributed organisms that existed for a relatively short geological time span. They're useful in correlating rock layers and in dating the rocks and the events that led to their formation.
Rock sequences provide information about the order in which geological events took place. This information can be used to understand the larger geological context and history of the region. The principle of stratigraphic superposition, which states that younger rock layers are deposited on top of older ones, is heavily utilized.
Learn more about Stratigraphy