Theory of Earth
Theory of Earth
复制标题
DOI：
--
复制
发表时间：
2014-12
影响因子：
16.6
通讯作者：
D. L. Anderson
中科院分区：
文献类型：
--
作者：
D. L. Anderson
地球科学的成熟导致了分裂成子学科，这些子学科彼此之间的交流并不完美。其中一些分支学科是野外地质学、岩石学、矿物学、地球化学、大地测量学和地震学，这些学科又被分成更细的单元。这门科学也扩展到包括行星甚至宇宙。这些领域的从业者往往以完全不同的方式看待地球。一个领域的发现只能缓慢地传播到另一个领域的专家的意识中。尽管事实上只有一个地球，但关于地球的理论可能比天文学、粒子物理学或细胞生物学的理论要多，因为在这些理论中，每个物体都有无数的样本。即使在学科之间存在串扰的地方，它通常也像静态一样嘈杂。一个学科的未经证实的假设或教条常常被视为理论家在稍微重叠的领域的严格边界条件。每个子学科的数据通常与一系列假设相一致。随着越来越多的不同数据被用于解决特定问题，可能性会大大缩小。地球的起源、组成和演化问题至少需要天文学、宇宙化学、陨石学、行星学、地质学、岩石学、矿物学、晶体学、材料科学和地震学的投入。对于一个研究地球的学生来说，这些都是人为的划分，无论它们对于在给定的战线上取得进展是多么必要。在《地球理论》一书中，我试图将与理解地球有关的各种学科的零碎知识集合起来。岩石和岩浆是我们关于内部最直接的信息来源，但它们偏向于地壳和浅地幔的性质。地震学是我们关于深部内部的最佳信息来源;然而，对地震数据的解释除了纯粹的结构之外，还需要固态物理学和实验岩石学的输入。虽然这不是一本关于地震学的书，但它以各种方式使用地震学。这里发展的“地球理论”在许多方面与传统观点不同。岩石学家对地球内部的模型通常集中在玄武岩和金伯利岩中所含地幔样品的组成上。基于这些样品的最简单的假设是，所观察到的玄武岩和橄榄岩彼此具有互补关系，橄榄岩是玄武岩的来源或其去除后的残留物，并且整个地幔在成分上与上地幔和玄武岩源区的推断化学成分相同。因此，地幔的成分是均匀的，因此地幔的所有部分最终都会上升到地表，形成玄武岩。俯冲板片在穿过地幔下落到核幔边界时没有障碍。
The maturing of the Earth sciences has led to a fragmentation into subdisciplines which speak imperfectly to one another. Some of these subdisciplines are field geology, petrology, mineralogy, geochemistry, geodesy and seismology, and these in turn are split into even finer units. The science has also expanded to include the planets and even the cosmos. The practitioners in each of these fields tend to view the Earth in a completely different way. Discoveries in one field diffuse only slowly into the consciousness of a specialist in another. In spite of the fact that there is only one Earth, there are probably more Theories of the Earth than there are of astronomy, particle physics or cell biology where there are uncountable samples of each object. Even where there is cross-talk among disciplines, it is usually as noisy as static. Too often, one discipline's unproven assumptions or dogmas are treated as firm boundary conditions for a theoretician in a slightly overlapping area. The data of each subdiscipline are usually consistent with a range of hypotheses. The possibilities can be narrowed considerably as more and more diverse data are brought to bear on a particular problem. The questions of origin, composition and evolution of the Earth require input from astronomy, cosmochemistry, meteoritics, planetology, geology, petrology, mineralogy, crystallography, materials science and seismology, at a minimum. To a student of the Earth, these are artificial divisions, however necessary they are to make progress on a given front. In Theory of the Earth I attempt to assemble the bits and pieces from a variety of disciplines which are relevant to an understanding of the Earth. Rocks and magmas are our most direct source of information about the interior, but they are biased toward the properties of the crust and shallow mantle. Seismology is our best source of information about the deep interior; however, the interpretation of seismic data for purposes other than purely structural requires input from solid-state physics and experimental petrology. Although this is not a book about seismology, it uses seismology in a variety of ways. The "Theory of the Earth" developed here differs in many respects from conventional views. Petrologists' models for the Earth's interior usually focus on the composition of mantle samples contained in basalts and kimberlites. The simplest hypothesis based on these samples is that the observed basalts and peridotites bear a complementary relation to one another, that peridotites are the source of basalts or the residue after their removal, and that the whole mantle is identical in composition to the inferred chemistry of the upper mantle and the basalt source region. The mantle is therefore homogeneous in composition, and thus all parts of the mantle eventually rise to the surface to provide basalts. Subducted slabs experience no barrier in falling through the mantle to the core-mantle boundary.