Authors: Clarice R. Perryman, Carmody K. McCalley, Avni Malhotra, M. Florencia Fahnestock, Natalie N. Kashi, Julia G. Bryce, Reiner Giesler, Ruth K. Varner
Permafrost is a blanket of soil that is frozen for more than two years and can trap its contents for hundreds to thousands of years. Now that permafrost soil is thawing. This is particularly significant in peatland permafrost because these wetlands sequester high amounts of carbon. As peatland permafrost degrades, methane emissions are expected to increase as the water table rises and provides a suitable environment for methane production by microbes.
Continue reading “Unexpected consequence of permafrost thaw: potentially less methane released into the atmosphere”
Author’s Note: The last few weeks have left us grappling with the profound effects of systemic racism, as seen in the wake of the recent protests and violence all over the USA and the world, as well as the disproportionate effect of COVID-19 on Black communities. This week’s post is dedicated to exploring the impact of another effect of systemic racism: lack of representation in educational spaces, made apparent in geology textbooks.
Continue reading “Whose Faces do we See in Geology Textbooks?”
Paper: Evolution of modern river systems: an assessment of ‘landscape memory’ in Indian river systems
Authors: Vikrant Jain, Sonam, Ajit Singh, Rajiv Sinha, S. K. Tandon
“A river cuts through rock not because of its power, but because of its persistence.”James N Watkins
In geomorphology, the persistence of rivers is etched into the very landscape – a memory of the forces that once shaped it, and continue to do so, slowly, and inexorably. Landscape memory, as Gary John Brierley once wrote, is the imprint of the past upon contemporary landscapes, which include geologic, climatic, and anthropogenic factors.
The rivers of the Indian subcontinent bear witness to forces that shaped them over millennia – and a recent publication in the Journal of International Geosciences traces the evolution of India’s river systems at different time scales.
Continue reading “Rivers of Memory: India”
Featured image: Deforestation in Madagascar, image credit: Gregoire Dubois, CC BY-NC-SA 2.0, on Flickr.
Paper: Relationships between climate change, human environmental impact, and megafaunal extinction inferred from a 4000-year multi-proxy record from a stalagmite from northwestern Madagascar
Authors: L. B. Railsback, L. A. Dupont, F. Liang, G. A. Brook, D. A. Burney, H. Cheng., and R. L. Edwards
Madagascar is so large and ecologically unique that it has been dubbed a continent in its own right. It wasn’t occupied by humans until 3,000 years ago and the island’s megafauna died out comparatively recently. Just 1000 years ago sloth lemurs the size of pandas, 10-foot tall elephant birds, and a puma-like predator called the giant fossa roamed the island.
Continue reading “Humans most likely drove Madagascar’s megafaunal extinction”
Featured image: A perspective view of the seafloor at the East Pacific Rise, 9N. Made with GeoMapApp (www.geomapapp.org, CC-BY), and GMRT topography data (Ryan et al. 2009, CC-BY).
Paper: Do sea level variations influence mid-ocean ridge magma supply? A test using crustal thickness and bathymetry data from the East Pacific Rise
Authors: B. Boulahanis, S. M. Carbotte, P. J. Huybers, M. R. Nedimovic, O. Aghaei, J. P. Canales, and C. H. Langmuir
Many of our records of past sea level come from local measurements from coastal towns logged over decades or centuries, or are estimated from ice or sediment cores spanning the last few thousand years, but new research suggests that much longer records can be found in an unlikely place: imprinted deep underground in the oceanic crust.
Continue reading “Climate records written on the seafloor”
Featured image by Jennifer Crowder from Pixabay.
Paper: Enhanced, climate-driven sedimentation on salt marshes
Authors: D.M. FitzGerald, Z.J. Hughes, I.Y. Georgiou, S. Black, A. Novak
Journal: Geophysical Research Letters
Accelerated sea level rise threatens to drown many of the world’s salt marshes, but sediment riding on ice rafts might be coming to the rescue.
Continue reading “Sediment riding on ice to the rescue of vulnerable salt marshes”
Featured image: Cambrian stromatolites from New York State. Image attribution: James St. John / CC BY 2.0; Wikimedia Commons
Paper: Evidence for microbes in early Neoproterozoic stromatolites
Authors: Zhongwu Lan, Shujing Zhang, Maurice Tucker, Zhensheng Li, Zhuoya Zhao
Stromatolites are ancient, layered deposits of sediments that are characterized by thin, alternating light and dark bands. While microbial fossils have been found in many stromatolites, the biological origin of these structures has been debated. Continue reading “Ancient microbes engineered sedimentary deposits”
Featured image: A fence broken by the 1906 San Francisco earthquake, by G. K. Gilbert. Public domain.
the millions of people living near the San Andreas fault zone in
California, the billion-dollar question is when the next “big one”
is going to happen.
Continue reading “How to locate oceanic earthquakes without getting your feet wet”
Featured image: Pitztal Glacier, Austria by annca on Pixabay
Paper: Increased Subglacial Sediment Discharge in a Warming Climate: Consideration of Ice Dynamics, Glacial Erosion, and Fluvial Sediment Transport
Authors: Ian Delaney and Surendra Adhikari
The world’s glaciers are shrinking, sending great quantities of water downstream in a geologic instant. But new research shows a lesser-known effect of climate warming: a large increase in sediment released from melting glaciers that might rearrange the shape of Earth’s surface.
Continue reading “Do melting glaciers release extra sediment?”
Featured image: The Yellow River Breaches its Course by Ma Yuan, Public Domain
Paper: Uranium isotopic constraints on the nature of the prehistoric flood at the Lajia site, China
Authors: Le Li, Jun Chen, David William Hedding, Yuanhe Fu, Maolin Ye, Gaojun Li
A small sand deposit might hold the key to dating the rise of China’s first dynasty.
Continue reading “What Caused the Flood that (Possibly) Gave Rise to an Empire?”