The kind of mountain range formed when tension causes large blocks of crust to drop down is called a horst and graben structure.

Here's a breakdown:

* Horst: A horst is an elevated block of crust. Think of it as a raised block, like a plateau.

* Graben: A graben is a lowered block of crust. Imagine a valley or depression.

When tension pulls on the Earth's crust, it can cause it to fracture. These fractures, called faults, can create a series of horsts and grabens. The horsts are the uplifted blocks, and the grabens are the down-dropped blocks.

Example:

The Basin and Range Province in the western United States is a classic example of a horst and graben structure. This region is characterized by alternating ranges (horsts) and valleys (grabens).

Let me know if you'd like to explore more about horst and graben structures or other types of mountain ranges!