Chinese surnames are used by Han Chinese and Sinicized ethnic groups in Mainland China, Hong Kong, Macau, Malaysia, Taiwan, Korea, Singapore, Vietnam and among overseas Chinese communities. In ancient times two types of surnames existed, namely xing (Chinese: å§; pinyin: xÃ¬ng) or lineage names, and shi (Chinese: æ°; pinyin: shÃ¬) or clan names.
An ice sheet is a large permanent layer of ice covering a continental shelf, defined as having an extent greater than 50,000 km2 (19,305 mi2). An ice sheet is larger than a glacier or ice shelf.
Antarctica's ice sheet flows around mountains. Ice sheets are sometimes called polar ice caps. On Mars, the polar ice caps are called the Planum Australe (southern) and the Planum Boreum (northern). The Martian ice caps are made of water and carbon dioxide about 3 kilometers (1.9 miles) thick.