Dark Sun Terrain: Mountains

Himalayan Mountains, Asia

Mountain ranges consist of a series of mountains in a line and connected by high ground. There are numerous mountain ranges in the Tablelands, including the Black Spine Mountains, the Mekillot Mountains, the Windbreak Mountains, and the Ringing Mountains. These mountain ranges are made up of various types of rock and stone. While they can be very different, they are also very similar. All mountains are large landforms that rise above the surrounding area. These usually form peaks or small plateaus.
The Ringing mountains are the largest peaks in the Tablelands and the only ones capped in snow. They are made up of granite, diorite, monazite, shale, and limestone. High quality garnets are mined in the Ringing Mountains. From a distance of a hundred miles, the Ringing Mountains look like a ridge of reddish clouds hugging the horizon. As you move closer, their soft edges gradually grow sharper and more distinct. Within five miles of the mountains, the range takes on the appearance of a great wall.
The Windswept Mountains are made up of sandstone, shale, and limestone. They mark the northwestern base of the Ivory Triangle region. This high mountain range juts abruptly from the sandy wastes at the edge of the Tablelands on its northwestern side. These mountains are called the Windbreak Mountains because they protect the Gulg and Nibenay region from the prevailing west winds blowing off the Tablelands.
The Black Spine and Mekillot Mountains are made up of granite, gneiss, mudstone, and limestone. The Mekillot Mountains are an old, low-lying range in the center of the Great Ivory Plain. They're shaped like the backs of giant mekillots. The Black Spine Mountains are east of the Windbreak Mountains. They look like a huge gith, with a granite spine. Both of these mountain ranges get little rain.
There are other mountain ranges in the Tablelands as well, such as the Smoking Crown Mountains, the Kregill Mountains, and the mountain range near South Ledopolous. These mountain ranges are likely similar to the dry Black Spine and Mekillot Mountain ranges in composition, flora, and fauna.

Olympus Mons, Mars

The Ringing and Windbreak Mountains get a lot of rain compared to the other mountain ranges in the Tablelands, at least on their forested sides, which alters the animals that are present. The animals that I'll be discussing live the barren areas of those mountains, as well as other mountain ranges. The creatures that call the mountains home have to be hardy and tough to live in such barren terrain.
From simple Lirrs to savage B'rohgs, the mountains offer dwellings for creatures of all sizes. The footing is often treacherous and pathways small, so it's not too common to see huge creatures here. Flying creatures do not suffer such difficulty, so flying creatures of all sizes lair in the mountains. Flora is generally uncommon, but the plants that do grow are covered in thorns.
Traveling in the mountains is tedious and dangerous. A traveler usually has to forego mounts and wagons because the footing is treacherous. In addition, a traveler will usually have to climb over boulders and other dead ends at some point. To complicate things further, paths twist and turn, so traveling in a straight line is impossible. Other hazards include loose rock below that cause travelers to slip and loose rocks from above that may fall on travelers. In the Ringing and Windbreak Mountains, there is also the danger of altitude sickness.

Windswept Mountains, Iran

Food and water may be easy to find, but not easy to get to. Seeing an oasis three hundred feet down a sheer cliff isn't much help. Meat is the most common food source available, as plants are tough and burred. Water may be found in cracks and crevices and are hopefully accessible to the traveler. On the bright side, is that water is less likely to evaporate quickly in higher altitudes.

Official Rules: Characters traveling over mountains move at 1/6 of their movement rate.

House Rules: Every 1d8 hours of travel in the mountains requires a climbing check to bypass a barrier. Failure means the characters have been injured for 2d6 points of damage, or whatever the DM decides is appropriate. Player characters may avoid this check by lowering their move rate to 1/10 of their movement rate, minimum 1.

Special note about the Klar. The Klar in Terrors Beyond Tyr is listed as living in the Mekillot Mountains, however is it also listed in the Encounter Tables in the Mountain category. I believe that Klars live in all mountain ranges, but are more common in the Mekillot Mountains. So, in the Mekillot Mountains, treat Klars are uncommon rather than rare.