Mary Tharp was a pioneering geologist and oceanographic cartographer who, together with Bruce Heezen, created the first comprehensive maps of the ocean floor. Her work revealed the global mid-ocean ridge system, a continuous chain of underwater mountains stretching around the planet, and provided some of the first convincing visual evidence for plate tectonics.
This painting is still the clearest depiction I know of the ridge system. When zooming in on the ridges around Iceland, we can clearly see that a continuous structure lies beneath the island: the Reykjanes Ridge to the south and the Kolbeinsey Ridge to the north, separated only by Iceland and the Icelandic shelf.
It is also fascinating to look at the globe Tharp and Heezen created, where the ridges are marked all around the world. Seeing the system on a sphere makes it much easier to grasp how continuous these features really are, something that is very difficult to comprehend on a flat map. Creating a globe like that must have been a crucial part of their work, helping them visualize Earth’s dynamic structure as a truly interconnected system.
https://en.wikipedia.org/wiki/Marie_Tharp
1977: The culmination of Tharp’s decades of work came with the publication of “The World Ocean Floor”, a full world map of the ocean ridges, created in collaboration with artist Heinrich Berann. This was the first global visualization of the continuous mid-ocean ridge system encircling the planet.
Of course it is tempting to add some aspects of the convection rolls model here:
t’s hard not to be impressed by the remarkable regularity of the pattern — at once striking, convincing, and precise. The main structural divisions appear at consistent 30° intervals, outlining a symmetry that is anything but coincidental. Even with the thinnest possible lines, the geometry stands out clearly: the 30° spacing traced along the equator, the continuous arc of the Ring of Fire encircling the Pacific Ocean, and the 90° separations linking the major mid-ocean ridges across the Southern Hemisphere. Together, these alignments suggest a coherent global framework — a kind of planetary rhythm — that underlies both surface geology and deeper mantle dynamics.
Magic Magma 