World map 1:50000000

Author: Compiled by the Press
Publisher:
Publish Date: 2003-01-01
Features: Most of the Earth's surface is ocean, with land accounting for only a small portion. The total surface area of the Earth is approximately 51 million square kilometers, of which the ocean covers about 36 million square kilometers, accounting for 70.8% of the total surface area. The land covers about 14.9 million square kilometers, accounting for 29.2% of the total surface area. In other words, seven-tenths of the Earth's surface is ocean, and three-tenths is land. The land on the Earth's surface is divided into many pieces of varying sizes by the ocean. Generally, large landmasses surrounded by the ocean are called continents, while small landmasses are called islands. Continents and the islands near them are collectively referred to as continents. In this way, the land on the Earth's surface is divided into six continents: the Eurasian continent, the African continent, the North American continent, the South American continent, the Antarctic continent, and the Australian continent. The oceans on the Earth's surface are interconnected, forming a unified world ocean. Based on the distribution of land and sea, the world's oceans can be divided into four parts: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean. There are no natural boundaries between them, and they are usually divided by underwater ridges or certain meridians. The elevation of the Earth's surface varies greatly, and its morphology is diverse. Landforms are typically divided into plains, plateaus, basins, mountains, and hills. They are distributed in different scales on the continents and collectively form a rugged and uneven surface. The mountains on land have two huge mountain ranges: one is the Pacific Ring of Fire, which extends in a north-south direction along both sides of the Pacific Ocean, namely the Cordilleran-Andean mountain system running through the western part of the North American continent, and the mountains along the Pacific coast of Asia and Australia and the island arcs of East Asia. The other is roughly oriented east-west, stretching across the central and southern part of the Eurasian continent and the northern edge of the African continent. Its western part includes the Alps and the Atlas Mountains, which, after entering Asia, merge with the mountains on both sides of the Turkish Plateau, the Hindu Kush Mountains, the Karakoram Mountains, and the Himalayas. It then continues through the western mountains of the Indochina Peninsula and extends to the southern island arcs of the Sunda Islands, connecting with the Pacific Ring of Fire. The two major mountain ranges are products of the Alpine orogeny, with high and majestic terrain, abundant volcanoes and earthquakes. The plains on land are generally distributed in the middle of the continents, with mountains surrounding both sides, forming three longitudinal geomorphic belts. This is most prominent in the North American continent, and the Australian continent also has a similar topographic structure. However, on the Eurasian continent, plains are primarily found north of the east-west mountain ranges, such as the Central European Plain, the East European Plain, the West Siberian Plain, and the Turan Plain. On the southern side, plains are mostly formed by alluvial deposits and are distributed between plateaus, such as the Mesopotamian Plain, the Indus-Ganges Plain, as well as the Northeast Plain, the North China Plain, and the Middle-Lower Yangtze Plain in China. The land is also widely covered with large uplifted plateaus, which generally have Precambrian ancient continental blocks as their cores, with relatively stable crusts and gentle surface relief. Examples include the plateaus of the African continent, the Central Siberian Plateau, the Mongolian Plateau, the Arabian Plateau, and the Deccan Plateau on the Eurasian continent, the Brazilian Plateau on the South American continent, and the northern plateau of the Australian continent. The Antarctic continent, similar to the African continent, is also dominated by plateaus but is covered with thick ice layers. Additionally, there are plateaus embedded between young mountain ranges on land, with relatively active crustal movements, high elevations, and significant surface relief, such as the Tibetan Plateau, the Anatolian Plateau, the Iranian Plateau, and some intermontane plateaus distributed within the Cordilleran-Andean mountain system. Small landmasses scattered in the ocean, rivers, or lakes are called islands. The world's islands account for about 7% of the total land area, with the largest island being Greenland in northeastern North America. Many islands close to each other are collectively referred to as archipelagos, such as the Malay (South Sea) Archipelago and the West Indies. A peninsula is a piece of land extending into the ocean or a lake, surrounded by water on three sides and connected to the mainland on one side, such as the Arabian Peninsula and the Indochina Peninsula.