海平面变动及原因（Sea level changes and causes）.docVIP

海平面变动及原因（Sea level changes and causes） Causes of sea-level change The sea level changes are controlled and affected by many factors mainly include: glaciers, sea level change, tectonic and sea-level changes - geoid sea-level changes and water balance, glacier equilibrium effect and rheological equilibrium effect etc.. Glacier sea level change. In cold climates, ice sheets are forming around the poles, reducing the amount of water in the ocean and lowering sea levels. When the weather gets warmer, the ice caps melt, ice water flows back into the ocean, and sea levels rise. Different scholars estimate global modern glacier volume in (20 ~ 34.75) between x 10 - cubic kilometers, if all melted, will make the sea level rise from 50 to 85 meters (without considering the balance due to increased water seabed subsidence). By the size of the ice sheet at the end of the Quaternary ice age, the sea level was 135 meters lower than it is now. The magnitude of this eustatic range is estimated by different scholars. It mainly depends on how to estimate the ice sheet thickness of the Antarctic continent. Nevertheless, the argument that sea-level changes are mainly caused by glacial fluctuations since Quaternary have been basically accepted. Tectonic sea level change. The sea level changes caused by the structure are global and some local. The role of global sea level change caused by tectonic movements, changes in ocean floor volume Xinyang basin or sink. The total volume of the world ocean increases, lowering sea level. On the contrary, the ocean floor uplift, some ocean disappeared, can make the sea level rise. The plate tectonic theory holds that the sea-level change is related to the rate of submarine spreading. The material in the ocean ridge hyperplasia is hot, and gradually cooling, more dense over time, so in the process of ocean lithosphere horizontal expansion moving with time sinking. If the expansion rate is fast, from the top of the ridge in a certain distance from the