Fossils Flashcards
What is a marine transgression?
Occurs when sea level rises relative to the land, causing the ocean to move inland and cover more of the continent.
What happens to the shoreline during a marine transgression?
The shoreline migrates landward as the sea level rises.
How do environments parallel to the shoreline change during a marine transgression?
Environments parallel to the shoreline (such as beaches and coastal ecosystems) also migrate landward as more of the land gets covered by the rising sea.
What is facies superposition in the context of marine transgression?
During a marine transgression, offshore facies (deposited in deeper waters) are stacked on top of nearshore facies (deposited closer to land).
How does the age of rock layers change as you move landward during a marine transgression?
The rocks become younger as you move landward because newer rocks are deposited in nearshore areas as the sea level rises.
Why do offshore facies become stacked on top of nearshore facies during a marine transgression?
The rising sea level causes deeper waters to move landward, leading to the deposition of offshore facies over the existing nearshore facies.
How does the rising sea level affect the types of rocks deposited along the shore?
As the sea level rises, the types of rocks deposited change from nearshore (shallower water) to offshore (deeper water) facies. These new layers are stacked on top of older ones.
In a marine transgression, where are the younger rocks located?
The younger rocks are found closer to the land, as the sea covers more of the continent.
What does it mean for the rocks to become younger as you move landward?
It means that as sea level rises and the ocean moves inland, newer rock layers are deposited in the shallower, nearshore environments, while older rocks are found further from the land in deeper waters.
What is the general effect of marine transgression on the land and environment?
Marine transgression leads to the flooding of land areas, shifting environments, and depositing new layers of sediment in different orders (younger nearshore, older offshore).
