Introduction to Neotectonics and Bioregionalisation
Neotectonics has undergone incredible development since Vladimir Obruchev proposed the term in 1948 . With the discovery of mid-oceanic ridges, subduction, mantle flow, and dynamic topography, neotectonics has become the forefront of tectonic research. Th
- PDF / 341,013 Bytes
- 9 Pages / 439.37 x 666.142 pts Page_size
- 92 Downloads / 194 Views
Introduction to Neotectonics and Bioregionalisation
Abstract Neotectonics has undergone incredible development since Vladimir Obruchev proposed the term in 1948. With the discovery of mid-oceanic ridges, subduction, mantle flow, and dynamic topography, neotectonics has become the forefront of tectonic research. This chapter attempts to unite two fields, neotectonics and bioregionalisation, the latter being a result of the former.
1.1 N eotectonics: Dynamic Topography and Landscape Evolution Neotectonics, a subdiscipline of tectonics, deals with Neogene intra-plate deformation due to the down and upwellings in the mantle that lead to dynamic topography and landscape development (e.g. formation of cratonic basins or alteration of drainage and erosion patterns) within recent geological time periods (i.e. since the Miocene). Although these processes operating on landscapes are presumed to have operated throughout Earth’s geological history, only recent geomorphological features associated with neotectonics processes will still be preserved due to the ravages of erosion. The term neotectonics was first coined by Russian geologist Vladimir Obruchev (1863–1956), who proposed to “call the structures of the Earth’s crust as neotectonics. Such structures had been created during the youngest movements of the crust, which had occurred at the end of the Tertiary Period as well as in the first half of the Quaternary Period”. Obruchev did not support Wegner’s continental drift hypothesis but rather considered “the movements (moving) of the Earth’s crust, namely the processes of geotectonics, from the point of view of the pulsation hypothesis of [Mikhail Antonovich] Usov and [Walter Hermann] Bucher” (Obruchev 1948, p. 13, translation by E.V. Mavrodiev). Present-day neotectonics incorporates Obruchev’s youngest structures as well as plate tectonic theory, in particular mantle flow due to slab subsidence or divergent margins.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2020 M. C. Ebach, B. Michaux, Biotectonics, SpringerBriefs in Evolutionary Biology, https://doi.org/10.1007/978-3-030-51773-1_1
1
2
1 Introduction to Neotectonics and Bioregionalisation
1.1.1 The Geoid In order to understand neotectonics, it is first necessary to introduce the concept of the geoid (Fig. 1.1). Imagine a snapshot of the entire surface of the Earth. In this two-dimensional picture, we can see the surface of the oceans without any influence from the tides, wind, or air pressure. The geoid, a hypothetical surface, which extends under the continents, is equivalent to a mean sea level. The only influences on the shape of the geoid are gravity and the rotation of the planet. Because the Earth’s gravity varies due to the uneven distribution of mass and heterogeneity in the density of the underlying mantle, the geoid shows how differences in crustal thicknesses and irregularities in the upper mantle effect the elevation of oceans and continents with respect to the reference ellipsoid, which is another hypothetical su
Data Loading...
