Lemme see if I can still write even just a background geomorphic report:
From distance references and time of travel, Middle Earth is slightly bigger than the European major peninsula starting from the North West in the Shire (British Isles) going South East to Mordor (Asia Minor or Near East.)
The entire super-peninsula is temperate and weather systems are highly localized, with no wide cloudless belt forming a desert region. There is a major divide of uplifted mountains running North-South called the Misty Mountain. The range is also fault-controlled; with the river Anduin following the surface projection of the fault from north to south. The misty mountains appear young given their shape and the quality of soil on either side. they are a bit like the Rockies in attitude rather than the Appalachians.
Near the Gap of Rohan, there is an assumed East-West trending right-lateral fault that broke the southern half of the Misty Mountains and drove it farther to the East. The Southern half of the Misty Mountains forms the Western mountainous border of Mordor.
The Eastern side, from Wilderland, going down to Gondor and Harad, appears down-thrown compared with the West. This is evidenced by low countries that are thickly forested, with marshes and swamps especially near the river and the estuarine areas.
Despite the West side being uplifted, the land appears more stable and large areas are available for human settlement, farming, and animal husbandry. This may be the result of wide deposition and uplifting from previous orogenic episodes, much older than that which formed the Misty Mountains.
The most recent tectonic activity are in Mordor in Mount Doom, and slightly older volcanic episodes in the north which, by popular legend, was inundated due to violent battles 6,000 years past.