Reconstructing vanished oceans
We establish the locations and geometry of mid ocean ridges through time on the basis of marine magnetic anomaly identifications, geological information such as paleomagnetic data from terranes and microcontinents, especially in the Tethys Ocean, mid-oceanic ridge subduction events and the rules of plate tectonics. Based on a global set of tectonic plate rotations we construct a set of refined seafloor isochrons following the interpolation technique outlined by Müller et al. (1997; 2008) but including a multitude of additional data.
Oceanic depth through time
Using a published age-depth relationship (GDH-1), we compute the depth-area distribution of the ocean basins. We choose GDH-1 for converting age to depth because this relationship is based on sediment-corrected depths without excluding data from hotspot swells and seamounts. Therefore GDH-1 provides a good average fit to sediment unloaded oceanic basement depths and is preferable for predicting the average oceanic basement depth through time, including thermally rejuvenated lithosphere, as compared to models that reflect ocean depth changes related to plate ageing through time only.
Three additional factors play a significant role in controlling global ocean basin depth through time, namely the generation of oceanic large igneous provinces (LIPS), oceanic sedimentation (2) and changes in oceanic crustal area. We create a set of paleo-bathymetry maps by adding major oceanic plateaus and sediment thickness to our reconstructed basement depth maps. These maps allow us to compute oceanic crustal area and mean depth through time.
Palaeo Age and Bathymetry
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