Geology seeks to understand the structure and behavior of Earth’s interior, and the mantle plays a central role in this system.
Located between the crust and the core, the mantle accounts for the majority of Earth’s volume.
Although it is composed largely of solid rock, the mantle does not behave as a rigid body.
Over geological time, its material can slowly flow under intense heat and pressure.
The mantle is commonly divided into the upper mantle and the lower mantle, separated by zones of changing mineral structure.
In the upper mantle, high temperatures cause rocks to deform plastically rather than fracture.
This slow movement drives convection currents, which transfer heat from Earth’s interior toward the surface.
These currents are a key force behind plate tectonics, influencing the movement of continents and the formation of geological features such as mountains and volcanoes.
Advances in seismic technology have allowed scientists to study the mantle indirectly.
By analyzing how seismic waves travel through Earth during earthquakes, researchers can infer variations in temperature, composition, and density within the mantle.
Differences in wave speed suggest that the mantle is not uniform but contains regions with distinct physical properties.
Despite these insights, many aspects of the mantle remain uncertain.
Direct sampling is impossible due to extreme depths and conditions.
As a result, scientists rely on models and indirect evidence, continuously revising their understanding as new data emerges.
The mantle, though hidden from view, remains essential to explaining Earth’s dynamic surface and long-term evolution.
Summary
The passage explains that the Earth’s mantle, located between the crust and the core, makes up most of the planet’s volume and plays a crucial role in geological processes.
Although composed mainly of solid rock, the mantle does not remain rigid; under high temperature and pressure, its material flows slowly over long periods.
This slow, plastic movement generates convection currents that transfer heat upward and drive plate tectonics, shaping continents, mountains, and volcanoes.
Because the mantle cannot be directly accessed, scientists study it indirectly through seismic waves, using variations in wave speed to infer differences in its internal structure.
Despite ongoing uncertainties, the mantle is essential to understanding Earth’s dynamic surface and long-term evolution.
繁體中文摘要
本文說明地函位於地殼與地核之間，佔據地球體積的大部分，並在地質作用中扮演關鍵角色。
雖然地函主要由固態岩石構成，但在高溫與高壓下，其物質能於漫長的地質時間尺度中緩慢流動，呈現可塑性行為。
這種緩慢流動形成對流，將熱量向上傳遞，並驅動板塊構造運動，進而塑造大陸、山脈與火山。
由於無法直接取得地函樣本，科學家透過分析地震波的傳播情形來推測其內部結構。
儘管仍存在不確定性，地函仍是理解地球動態表面與長期演化不可或缺的關鍵。