Mesa Rica Sandstone facts for kids
Quick facts for kids Mesa Rica SandstoneStratigraphic range: Albian |
|
|---|---|
| Type | Formation |
| Unit of | Dakota Group |
| Underlies | Pajarito Formation |
| Overlies | Tucumcari Shale, Glencairn Formation |
| Thickness | 33 meters (108 ft) |
| Lithology | |
| Primary | Sandstone |
| Location | |
| Coordinates | 35°13′37″N 104°13′23″W / 35.227°N 104.223°W |
| Region | New Mexico, Oklahoma |
| Country | United States |
| Type section | |
| Named for | Mesa Rica |
| Named by | Dobrovolny, Summerson, and Bates |
| Year defined | 1947 |
The Mesa Rica Sandstone is a special rock layer found in Oklahoma and New Mexico. It's like a giant history book made of rock. This formation holds amazing fossils from the Cretaceous period. This was a time when dinosaurs roamed the Earth!
Contents
What is the Mesa Rica Sandstone?
The Mesa Rica Sandstone is mostly made of sandstone. This sandstone is often white to light brown. It has cool patterns called crossbeds. These patterns show how ancient sand dunes or river channels moved. The sand grains are medium to coarse in size.
This sandstone is very pure. It is made almost entirely of quartz and kaolin. This purity might mean it formed from older, worn-down rocks. Or, it could be because it formed very slowly. This allowed water to wash away other minerals over a long time.
At its bottom, the Mesa Rica Sandstone sometimes has small pebbles of quartz. It sits on top of other rock layers. These layers are called the Tucumcari Shale or Glencairn Formation. Above it, you'll find the Pajarito Formation. The Mesa Rica Sandstone can be as thick as 33 meters (108 ft).
This rock layer formed in an ancient river delta environment. This was a place where rivers met a larger body of water.
Dinosaur Tracks and Other Fossils
The Mesa Rica Sandstone is famous for its dinosaur fossils. Scientists have found bones that help them identify the types of dinosaurs that lived here.
The "Dinosaur Freeway"
The upper part of this rock layer has many dinosaur footprints. It is part of a huge area called the "dinosaur freeway." This "freeway" stretches across New Mexico, Colorado, and Oklahoma. It shows where many dinosaurs walked long ago.
Dinosaur tracks were first found at Clayton Lake State Park in 1982. More tracks were found at Mosquero Creek in 1986. Even more were discovered at Mills Canyon in 1995. The Mills Creek site has twelve different paths made by dinosaurs.
The tracks at Clayton Lake are special. They show dinosaurs dragging their tails as they walked. You can visit these tracks today. There's a trail with signs to explain them. However, the tracks are slowly wearing away due to weather.
Most of the tracks found at these sites belong to a dinosaur called Charirichnium leonardii.
Mosquero Creek Tracks
At Mosquero Creek, scientists found tracks from 81 different plant-eating dinosaurs. These tracks show at least two different species. One rare track even shows a dinosaur that was limping! The tracks also suggest that these dinosaurs moved together in groups.
Ancient Sea Life
The lower part of the Mesa Rica Sandstone holds fossils of sea creatures. These include ammonites. Ammonites were ancient sea animals with spiral shells. One type found here is called Mortoniceras equidistans.
How Scientists Studied It
The Mesa Rica Sandstone was first named in 1947. It was called the Mesa Rica sandstone member of the Purgatoire Formation. This was done by scientists Ernest Dobrovolny, Charles Summerson, and Robert Bates.
Later, in 1959, Robert Griggs and Charles Read changed its status. They made it a full "formation." This means it became a major, distinct rock unit on its own. They also stopped using the name Purgatoire Formation in northeastern New Mexico.
