When the Earth formed, it was covered by a hot magma ocean. So when and how did thick, silica-rich continental lithosphere form? Were the first, ancient continents similar to the present-day continents? And did the continents form in a burst of activity at a certain point, or was it a gradual build-up over Earth history?

In the podcast, Renée Tamblyn addresses these questions, as well as how early geological processes created molecular hydrogen that may have powered the first forms of life. In her own research, she has focused on the critical role played by water released from hydrous minerals that formed within oceanic lithosphere on the sea floor.

Tamblyn is a Postdoctoral Researcher at the University of Bern.

From East Africa to southwest USA, many regions of the Earth’s continental lithosphere are rifting. We see evidence of past rifting along the passive margins of continents that were once contiguous but are now separated by wide oceans. How does something as apparently solid and durable as a continent break apart?

In the podcast, Folarin Kolawole describes the various phases of rifting, from initial widespread normal faulting to the localization of stretching along a rift axis, followed by rapid extension and eventual breakup and formation of oceanic lithosphere.

Kolawole is especially interested in the early stages of rifting, and in his research he uses field observation, seismic imaging, and mechanical study of rocks. He is Assistant Professor of Earth and Environmental Sciences, Seismology, Geology, and Tectonophysics at the Lamont-Doherty Earth Observatory of Columbia University.

Most of Earth’s salt is dissolved in the oceans. But there is also a significant amount of solid salt among continental rocks. And because of their mechanical properties, salt formations can have a dramatic effect on the structure and evolution of the rocks that surround them. This gives rise to what we call salt tectonics – at first sight, a rather surprising juxtaposition of a soft, powdery substance with a word that connotes the larger scale structure of the crust.

In the podcast, Mike Hudec explains the origin of salt in the Earth’s crust and describes the structures it forms when subjected to stresses. He also discusses how salt can play in important role in the formation of oil and gas reservoirs.

Hudec is a research professor at the Bureau of Economic Geology at the University of Texas at Austin.