Rocky Surfaces main content.

Rocky Surfaces

Part of Hall of Meteorites.

C.2.2. Rocky surfaces hero

As newly formed planets melt, rocky material rises toward the surface, forming a mantle and crust.

In This Section

C.2.2.1. Cumberland Falls hero

Cumberland Falls

Look Closely

The large crystals in Cumberland Falls formed inside a partially molten aubrite asteroid, while the two black clasts, or fragments, come from a chondritic asteroid that never melted. The odd mixture was probably produced when the chondrite collided with the aubrite.

C.2.2.2. Peña Blanca Springs hero

Peña Blanca Springs

Matching Meteorites With Potential Parents

The Peña Blanca Springs meteorite belongs to a group, the aubrites, whose chemical composition has led to speculation that they came from the innermost asteroid belt, or possibly even the planet Mercury.

C.2.2.3. Kenna. Less melting hero

Kenna

Less Melting

Kenna, a ureilite, comes from an asteroid that did not completely differentiate. Instead, it only partially melted, then cooled and crystallized before it could separate into iron and stony parts.

Some ureilites contain primitive particles such as microdiamonds and chondrules that survived partial melting of the surrounding rock. In more fully melted meteorites, no chondrules remain.

C.2.2.4. Johnstown. More melting hero

Johnstown

More Melting

The Johnstown meteorite comes from a large asteroid, probably Vesta, that melted and differentiated. It is low in iron, nickel and other elements that sank to the asteroid core. It is also poor in aluminum and calcium, which seeped to the surface in volcanic basalts like the Camel Donga meteorite in this case.

This sample is the "main mass" of the Johnstown meteorite, meaning it is the biggest fragment of Johnstown ever found.