摘要
地球自转速度变慢说明地球在旋转的同时其体积在膨胀。这与红移现象等说明的宇宙膨胀是一致的。地球放射性物质的放射性能导致软流圈及塑性地核外核的形成。地球自转的惯性与地球塑性层的共同作用导致了地球的层间滑动。地球外圈应相对于内圈转动较慢。转动较快的内层层圈的运动方向为自西向东,或左旋剪切。即,软流圈之下的下地幔应相对于岩石圈自西向东转动较快;塑性地核外核之下的内核应相对于外核自西向东转动较快。在地球层圈之间的剪切力和地球放射性能所引起的热能的共同作用下,在软流圈产生物质的对流,形成地幔物质对流。推测地核的外核也可能会产生塑性物质的对流。地轴倾角ε的变化以及潮汐转矩和岁差转矩是地球动力学的重要因素。地球的旋转膨胀是板块运动的地球动力学基础,也是冈瓦纳古陆裂解的运动学基础。
The decrease of the Earth′s rotating speed implies its expansion during its rotation, which is consistent with the expansion of the universe indicated by the red-shift phenomenon. Radiogenic energy of radioactive materials in the Earth has led to the formation of the asthenoshphere and the fluid outer core. The joint action of the inertia difference of different layers during the earth′s rotation and the existence of fluid layers leads to the inter-layered gliding. The outer layers would rotate slower than the inner layers. As the Earth moves eastward, the inner layers which rotate faster would move eastward, resulting in sinistral shearing, because of its larger inertia. That is to say, the lower mantle beneath the asthenosphere would rotate faster eastward relative to the lithosphere, while the inner core beneath the liquid outer core would rotate faster eastward relative to the outer core. Due to the shearing between layers and heating of mass by radiogenic energy, the convection of mantle materials occurs within the asthenosphere. The convection of fluid materials is also considered to occur within the outer core. The expansion of the rotating Earth is the foundation of geodynamics. The movement of continental plates, such as the beak-up and dispersion of Gondwanaland including the southward drifting of Antarctic continent should be related to this expansion. The break-up of Gondwanaland took place during the transitional period when the speed of the earth′s rotation changed from slow deceleration in Jurassic to fast deceleration in Late Cretaceous. Since Cretaceous, along with the rapid slowing-down of the earth′s rotation, Gondwanaland has gradually broken up and dispersed. In other words, the break-up of Gondwanaland took place in the transitional period from Jurassic when the Earth slowly expanded to Late Cretaceous when the Earth rapidly expanded. Since then, fragments of Gondwanaland have dispersed and drifted to their present places respectively along with the rapid expansion of the Earth. The
出处
《地球学报》
EI
CAS
CSCD
北大核心
2005年第3期195-202,共8页
Acta Geoscientica Sinica
基金
国家自然科学基金项目"东南极及东非有关地区冈瓦纳古陆地壳性质
成因及运动学"(编号:49772154)
"1:500万南极洲地质图的编制及有关研究"(编号:48870098)
"南极洲地质发展与冈底纳古陆演化"(编号:40224010)成果之一。
