Stockton Formation facts for kids

The Stockton Formation is a special layer of rock found underground. It is a "bedrock unit," which means it's a main part of the Earth's solid crust. This rock layer is located in Pennsylvania, New Jersey, and New York.

Scientists named the Stockton Formation after Stockton, New Jersey. This is where they first studied and described it. This rock layer formed a very long time ago, during the Triassic Period.

What is the Stockton Formation?

The Stockton Formation is mostly made of different kinds of rock. It has light-gray, light-brown, or yellowish sandstone. Sandstone is a rock made from tiny grains of sand stuck together.

It also contains reddish or purplish-brown siltstone and mudstone. Siltstone is like sandstone but with even finer grains. Mudstone is made from hardened mud. Sometimes, you can find layers of shale and argillite mixed in too.

What makes up the Stockton Formation?

In New Jersey, the Stockton Formation also includes other interesting rocks. These are feldspar-rich pebbly sandstone and conglomerate. Conglomerate is a rock made of rounded pebbles and larger pieces cemented together. You can also find quartz-pebble conglomerate, which has quartz pebbles.

How did the Stockton Formation form?

The Stockton Formation formed in an area called a "bajada." Imagine a wide, gently sloping plain at the base of mountains. This is where the sediments settled.

What caused the Stockton Formation to appear?

The rocks in the Stockton Formation came from the breaking apart of a supercontinent called Pangea. As Pangea split, it created new landforms. The sediments that formed the Stockton came from mountains to the southeast. These mountains were mostly made of granite.

The sediments spread out across a flat plain. At the same time, the Lockatong Formation was also forming nearby. The Lockatong Formation is made of lake sediments. These lake sediments grew during wetter times in the Late Triassic Period. This means the Stockton and Lockatong formations formed at the same time, but in different environments.

What fossils are found in the Stockton Formation?

Scientists have found some cool fossils in the Stockton Formation. These include fossil ferns. One type found is called Sphenopteris sitholeyi. These fossils help us understand what plants lived during the Triassic Period.

How old is the Stockton Formation?

The Stockton Formation is part of the Upper Triassic System. This means it formed between 237 and 207 million years ago. That's a very long time!

It sits on top of many older rock layers from the Appalachian Piedmont region. It also mixes with the Lockatong Formation. Above the Stockton Formation, you can find the Passaic Formation.

Sometimes, you can see diabase rocks that have pushed into the Stockton Formation. Diabase is a type of igneous rock. Where this happens, the heat from the diabase can change the Stockton rocks. This creates local contact metamorphic rocks.