Featuring image: Lava lake in Hawaii Volcanoes National Park, May 1954. Photo by J.P. Eaton, Public Domain (C0).
Paper: Did transit through the galactic spiral arms seed crust production on the early Earth?
Authors: C.L. Kirkland, P.J. Sutton, T. Erickson, T.E. Johnson, M.I.H. Hartnady, H. Smithies, M. Prause
Plate tectonics reshape the face of Earth over long periods of time, but how the first continental crust evolved is still unclear. Now, a new investigation of very old rocks showed that Earth structure might have been influenced by the galactic dance of our solar system through the Milky Way.
The dating of old continental crust from the Precambrian (2.8 – 3.6 billion year old rocks) indicates that the formation of continental crust happened in cycles. Scientists discovered these cycles, which indicate that the crust didn’t form continuously, decades ago by dating minerals contained in continental crust all over the globe. Now, new research suggests that these cycles correspond to the periods where Earth passed through the spiral arms of our galaxy, the Milky Way.
Continue reading “The seeds of continental crust”
Featured image: Elevation map of a seamount in the central Pacific, shown in a persepctive view. Image courtesy of the NOAA Office of Ocean Exploration and Research (public domain).
Paper: Fluid-rich subducting topography generates anomalous forearc porosity
Authors: Christine Chesley, Samer Naif, Kerry Key, Dan Bassett
Open any geology textbook, and you’re guaranteed to find a cartoon of a subduction zone showing how an incoming oceanic plate dives down beneath another tectonic plate (either continent or ocean) on its way back into Earth’s deep interior. These simple sketches typically show the top of the incoming plate as a smooth, gently curved line meeting and joining another smooth line at the base of the overriding plate – and that’s not exactly wrong, given the enormous scale of a subduction zone compared to the smallness of the drawing. But if you zoom in far enough on oceanic tectonic plates, the seafloor is often rough and bumpy. What happens, then, when rough seafloor heads into a subduction zone?
Continue reading “Mysteries of the deep (and bumpy) seafloor”
Featured image: Steam rising from a pool in the Aguas Termales area near the base of Rincón de la Vieja volcano in Costa Rica. Courtesy of the Global Volcanism Program, Smithsonian Institution; photo by Paul Kimberly.
Paper: Effect of tectonic processes on biosphere-geosphere feedbacks across a convergent margin
Authors: K. M. Fullerton, M. O. Schrenk, M. Yucel, E. Manini, M. Basili, T. J. Rogers, D. Fattorini, M. Di Carlo, G. d’Errico, F. Regoli, M. Nakagawa, C. Vetriani, F. Smedile, C. Ramirez, H. Miller, S. M. Morrison, J. Buongiorno, G. L. Jessen, A. D. Steen, M. Martinez, J. M. de Moor, P. H. Barry, D. Giovannelli, and K. G. Lloyd
Plate tectonics describes the workings of our planet on the gigantic scale of continents and oceans, moving graduallly over hundreds of millions of years. But the tectonic processes that slowly shape and reshape the whole surface of the Earth also directly influence the lives of some of our planet’s tiniest residents: microbes. And those microbes, in turn, may have a larger effect on Earth’s carbon cycle than previously estimated.
Continue reading “Microbes, tectonics, and the global carbon cycle”
Featured image: a view of the Calico Basin in the eastern part of the Mojave Desert. Photo by Fred Morledge, CC BY-SA 2.5, via Wikimedia Commons.
Paper: Thin crème brûlée rheological structure for the Eastern California Shear Zone
Authors: Shaozhuo Liu, Zheng-Kang Shen, Roland Bürgmann, & Sigurjón Jónsson
A recent paper by Liu and colleagues aims to answer a fundamental question in geodynamics: are Earth’s tectonic plates more like a jelly sandwich, or a crème brûlée? It may sound silly, but these two models for crustal strength describe how tectonic plates might respond to stress changes due to earthquakes.
Continue reading “Cracking the code of the caramel crust”
Featured Image: Lake in a volcano’s crater at Mývatn, Iceland. Photo by Philipp Wüthrich on Unsplash.
Book: Iceland: Tectonics, Volcanics, and Glacial Features, Geophysical Monograph 247 (First Edition, 2020)
Author: Dr. Tamie J. Jovanelly
Figure Illustrations: Nathan Mennen
Additional Text: Emily Larrimore
Publisher: American Geophysical Union, John Wiley & Sons, Inc.
I have always wanted to go to Iceland and travel the countryside marveling at the island’s unique geology and icy wonder. Reading through Iceland: Tectonics, Volcanics, and Glacial Features by Dr. Tamie J. Jovanelly, I felt like I got my chance to tour Iceland; this time with a very experienced guide. Dr. Jovanelly has been to Iceland more than ten times since 2006 to explore and study and her familiarity with the place and the people who live there is engrained in this text.
Continue reading “Iceland’s constantly changing landscape: A Book Review”
Featured image: Lake Malawi, as seen from space. Image courtesy of ESA/MERIS, CC-BY-SA IGO.
Paper: Preferential localized thinning of lithospheric mantle in the melt-poor Malawi Rift
Authors: E. Hopper, J. B. Gaherty, D. J. Shillington, N. J. Accardo, A. A. Nyblade, B. K. Holtzman, C. Havlin, C. A. Scholz, P. R. N. Chindandali, R. W. Ferdinand, G. D. Mulibo, G. Mbogoni
Continental rifting, where one landmass slowly breaks apart into two pieces separated by a brand new ocean basin, is a fundamental part of plate tectonics. But it presents an apparent paradox: the tectonic forces pulling on the plates are thought to be much too weak to break the strong rocks of the continents.
Continue reading “How do you break up a continent?”