Juana Lopez Member facts for kids
Quick facts for kids Juana Lopez MemberStratigraphic range: Turonian |
|
|---|---|
| Unit of | Carlile Formation |
| Underlies | Niobrara Formation |
| Overlies | Codel Sandstone member of the Carlile |
| Thickness | 0–6 feet (0.0–1.8 m) |
| Lithology | |
| Primary | Sandstone with abundant carbonate fossil grains |
| Other | Gravel, Codel fragments |
| Location | |
| Coordinates | 35°29′12″N 106°12′04″W / 35.4866°N 106.2010°W |
| Country |  United States |
| Type section | |
| Named for | Mesita Juana Lopez Grant, six miles northwest of Los Cerrillos, New Mexico |
| Named by | Rankin |
| Year defined | 1944 |
The Juana Lopez is a special layer of rock found in the Carlile Shale formation. It's also the name for the ancient environment where this rock layer formed. This rock is a type of sandstone that contains lots of carbonate (like shell pieces). It formed during the Turonian age, which was part of the Upper Cretaceous period. You can find it in parts of southern and western Colorado, and northern and central New Mexico.
What is the Juana Lopez Member?
The Juana Lopez is a very interesting part of the Carlile Shale. Scientists sometimes call it "enigmatic" because it's a bit mysterious. It's made of sand mixed with many tiny pieces of ancient sea life. These include bits of coral, shells (especially from creatures called inoceramids), shark teeth, and bone fragments.
When you break a piece of Juana Lopez rock, it might smell like sulfur. This rock formed in a wide, shallow part of the ocean. The water had strong waves, but not much new mud or sand was washing in from the land.
How it Formed
The Juana Lopez layer formed during a time when the Western Interior Seaway was changing. This seaway was a huge, shallow sea that once covered much of central North America.
The Juana Lopez formed when the sea briefly pulled back after the Greenhorn cycle of ocean activity. Then, it was exposed on the land surface before the sea advanced again with the Niobrara cycle. This means it was a short period of time when the seafloor was exposed to air before being covered by water again.
Images for kids
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A fossil of an ammonite found in the Juana Lopez Member.
