to record the development, tenure, and break-up of supercontinents. There is a sharp decrease in passive margins between 500 and during the timing of Pangaea's assembly. The tenure of Pangaea is marked by a low number of passive margins during 336 to and its break-up is indicated accurately by an increase in passive margins. Orogenic belts can form during the assembly of continents and supercontinents. The orogenic belts present on continental blocks are classified into three different categories and have implications for interpreting geologic bodies. Intercratonic orogenic belts are characteristic of ocean basin closure. Clear indicators of intracratonic activity contain ophiolites and other oceanic materials that are present in the suture zone. Intracratonic orogenic belts occur as thrust belts and do not contain any oceanic material. However, the absence of ophiolites is not strong evidence for intracratonic belts, because the oceanic material can be squeezed out and eroded away in an intracratonic environment. The third kind of orogenic belt is a confined orogenic belt which is the closure of small basins. The assembly of a supercontinent would have to show intracratonic orogenic belts. However, interpretation of orogenic belts can be difficult. The collision of Gondwana and Laurasia occurred in the late Palaeozoic. By this collision, the Variscan mountain range was created, along the equator. This 6000-km-long mountain range is usually referred to in two parts: the Hercynian mountain range of the late Carboniferous makes up the eastern part, and the western part is called the Appalachians, uplifted in the early Permian. (The existence of a flat elevated plateau-like the Tibetan Plateau is under much debate.) The locality of the Variscan range made it influential to both the northern and southern hemispheres. The elevation of the Appalachians would greatly influence global atmospheric circulation. Supercontinental climate Continents affect the climate of the planet drastically, with supercontinents having a larger, more prevalent influence. Continents modify global wind patterns, control ocean current paths, and have a higher albedo than the oceans. Winds are redirected by mountains, and albedo differences cause shifts in onshore winds. Higher elevation in continental interiors produces a cooler, drier climate, the phenomenon of continentality. This is seen today in Eurasia, and rock record shows evidence of continentality in the middle of Pangaea. Glacial The term glacial-epoch refers to a long episode of glaciation on Earth over millions of years. Glaciers have major implications on the climate, particularly through sea level