Towaco Formation facts for kids
Quick facts for kids Towaco FormationStratigraphic range: Early Jurassic |
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Various colors and textures of Towaco Formation seen within Pines Lake area of Wayne, New Jersey.
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| Type | Geological formation |
| Unit of | Newark Supergroup |
| Underlies | Hook Mountain Basalt |
| Overlies | Preakness Basalt |
| Thickness | maximum of at least 1,115 feet (340 m) |
| Lithology | |
| Primary | Sandstone, siltstone, mudstone |
| Other | Conglomerate |
| Location | |
| Coordinates | 40°48′N 74°18′W / 40.8°N 74.3°W |
| Approximate paleocoordinates | 21°24′N 20°36′W / 21.4°N 20.6°W |
| Region | Newark Basin of Eastern North America Rift Basins |
| Extent | nearly continuous for ~35 miles (56 km) in New Jersey |
| Type section | |
| Named for | Towaco, New Jersey |
| Named by | Paul E. Olsen, 1980 |
The Towaco Formation is a special type of rock layer found in New Jersey. It's like a big, ancient puzzle piece that helps scientists understand Earth's history. This rock layer is named after the small village of Towaco, New Jersey, where it was first studied by a scientist named Paul E. Olsen.
Contents
What is the Towaco Formation?
The Towaco Formation is made up of different kinds of rocks. You can find reddish-brown, reddish-purple, gray, greenish-gray, and white sandstone here. The sand grains in these rocks can be thick or thin. There's also black siltstone and mudstone that contains calcium.
Sometimes, you might even find layers of conglomerate. This rock is made of larger, rounded pieces of other rocks stuck together. There's even a special layer about 1 meter (3 feet) thick made from volcanic ash and rock pieces.
How these rocks were formed
Imagine a time when the supercontinent Pangaea was breaking apart. This created big cracks in the Earth, and the land started to pull apart. The Towaco Formation formed in this area, called the Newark Basin.
- Much of the rock formed in dry, desert-like conditions. This is why many layers are reddish. They were laid down in places like dry lakebeds (called playas) and areas where rivers spread out their sediments (alluvial fans).
- But the Towaco Formation is special because it also has many layers that are not red. These layers formed during wetter times when deep lakes covered the land.
One cool thing about the Towaco Formation is that its rock layers show very long cycles of change. These cycles are about ten times thicker than the cycles seen in older rock formations like the Lockatong Formation and Passaic Formation. This means the environment changed in big, repeating patterns over a long time.
Compared to the rock layer below it, the Feltville Formation, the Towaco Formation has a lot more of those chunky clastic rocks, like conglomerate.
Ancient life found in the rocks
Scientists have found some amazing things preserved in the Towaco Formation!
- Fish fossils: You can find fossils of ancient ray-finned fish, especially a type called Semionotus.
- Dinosaur tracks: There are also tracks from different kinds of dinosaurs and other reptiles. These tracks show us what creatures walked here millions of years ago.
- Plant remains: You might find black, carbonized pieces of ancient plants, along with impressions of leaves and even root structures. Scientists have also found tiny pollen grains.
- Coprolite: Believe it or not, fossilized animal waste, called coprolite, has also been found! This helps scientists learn about the diet of ancient animals.
How old is the Towaco Formation?
The Towaco Formation is very old! It sits between two layers of basalt rock, which are hardened lava flows. It's above the Preakness Mountain Basalt and below the Hook Mountain Basalt.
Based on these layers, scientists believe the Towaco Formation was laid down about 198 to 197 million years ago. This was during the Hettangian stage, which is part of the Early Jurassic Period.
