Geobites – Page 6 – Down-to-Earth Geoscience Writing

February 25, 2022February 25, 2022

To understand Mars, scientists study Earth – but is this enough?

Featured Image: Top: Valley of the Moon, Atacama Desert, San Pedro, Chile, Earth. Image courtesy Alf Igel. Bottom: Jezero Crater, Syrtis Major Quadrangle, Mars. Image courtesy Kevin M. Gill.

Paper: Gradient studies reveal the true drivers of extreme life in the Atacama Desert

Authors: D. Boy, R. Moeller, L. Sauheitl, F. Schaarschmidt, S. Rapp, L. van den Brink, S. Gschwendtner, R. Godoy Borquez, Francisco J. Matus, M. A. Horn, G. Guggenberger, J. Boy

Space. The final frontier. Or is it? Boy and colleagues are not presenting the voyages of the Starship Enterprise, rather the clever investigation of scientists on Earth. Their continuing mission: to understand the development of life in extreme environments, and how certain places on Earth geologically represent Mars and other planet analogues. While Boy and colleagues are limited on intergalactic travel, their recent work clearly the defines expectations, inferences, and consequences of using a site on Earth as a replacement for another planet. They conclude that the nearby climate and environment surrounding these analogue locations may lead to inaccurate comparisons, by altering soil moisture and salt content, for example.

February 25, 2022September 26, 2022

What caused the end-Triassic Mass Extinction in the Oceans?

Feature Image: Outcrop of volcanic rock associated with the Central Atlantic Magmatic Province. This Large Igneous Province has a strong correlation to the onset of a mass extinction ~200 million years ago, however, an exact mechanism for the extinction has been difficult to determine. CC BY-SA 4.0, via Wikimedia Commons

Paper: Two-pronged kill mechanism at the end-Triassic mass extinction

Authors: Calum P. Fox; Jessica H. Whiteside; Paul E. Olsen; Xingquian Cui; Roger E. Summons; Kliti Grice

Journal: Geology

A recent study by Calum Fox and colleagues sheds light on what caused one of the “big five” mass extinctions on Earth since complex life emerged ~540 million years ago. They found that repeated pulses of volcanic activity were responsible for the extinction in two main ways: ocean poisoning caused by gaseous hydrogen sulfide (H₂S) rising through the water column (known as euxinia) and ocean acidification.

February 17, 2022February 17, 2022

Martian Past Revealed by New Analysis of 4 Billion-year-old Meteorite

Paper: Organic synthesis associated with serpentinization and carbonation on early Mars

Authors: Steele A, Benning LG, Wirth R, Schreiber A, Araki T, McCubbin FM, Fries MD, Nittler LR, Wang J, Hallis LJ, and Conrad PG.

The discovery of organic carbon in Martian meteorites has fueled scientific debates for more than four decades. Could these molecules be the chemical residue of Martian life?

February 15, 2022February 15, 2022

The first mass extinction

Featuring image: Life on during the Ordovician period looked very different then today. Animals like anomalocarididaes were very common, but many species vanished at the end of the Ordovician. A new study sheds light on the first mass extinction event. Model created by Espen Horn, photo: H. Zell, Creative Commons (CC BY-SA 3.0).

Paper: Geochemical Records Reveal Protracted and Differential Marine Redox Change Associated With Late Ordovician Climate and Mass Extinctions

Authors: N. P. Kozik, B. C. Gill, J. D. Owens, T. W. Lyons and S. A. Young

As mountains rise and continents fall apart, it not only changes the face of the Earth, but also drastically affects its inhabitants.

Earth’s biosphere was disrupted by several mass extinction events, often connected to great changes in large geologic cycles. These times of great disasters were also a chance for pioneers and led to great evolutionary leaps. A new study suggests that the oldest of the known major mass extinctions during the Ordovician was caused by a change in climate and the ocean’s circulation system.

February 8, 2022February 8, 2022

The third pole is in peril !

Featured image: The terminus of the debris-covered Gangotri glacier. CC BY-SA 4.0, via Wikimedia commons

Article : Accelerated mass loss of Himalayan glaciers since the Little Ice Age

Authors : Ethan Lee, Jonathan L. Carrivick, Duncan J.Quincey, Simon J. Cook, William H. M. James, Lee H. Brown

The health of Himalayan glaciers is deteriorating at an alarming rate. These Himalayan ‘water towers’ are on the brink of undergoing irreversible changes due to climate change, which in turn will have an adverse effect on the water and food security of South Asia. Getting a good idea of what might happen to these glaciers is imperative, but until now, glaciologists have focused on recent fluctuation patterns of these glaciers spanning the past few decades. In a new study, Lee and colleagues tried to reconstruct the glacial surface of some 14,798 Himalayan glaciers during the Little Ice Age and found that compared to other non-polar regions, Himalayan glaciers might be even more sensitive to fluctuations in the climate.

February 3, 2022February 3, 2022

Rapidly growing lakes are changing the drainage of the Tibetan Plateau

MODIS view of the Tibetan Plateau showing numerous lakes

Featured image: MODIS-Aqua image of the Qinghai-Tibet Plateau via NASA Earth Observatory, created by Jesse Allen.

Article: Ongoing drainage reorganization driven by rapid lake growths on the Tibetan Plateau
Authors: Kai Liu, Linghong Ke, Jida Wang, Ling Jiang, Keith S. Richards, Yongwei Sheng, Yunqiang Zhu, Chenyu Fan, Pengfei Zhan, Shuangxiao Luo, Jian Cheng, Tan Chen, Ronghua Ma, Qiuhua Liang, Austin Madson, Chunqiao Song

Whether we recognize it or not, the land surface around us is organized into watersheds or drainage basins–areas that share a common outlet for precipitation. On human timescales, drainage basins are typically fixed, because they are defined by the slopes and contours of topography that change very slowly or very infrequently. In the Tibetan Plateau, however, rapid climate change is altering drainage basins before our eyes. Recently, Liu and colleagues from China, the United States and the United Kingdom used satellite data to identify dramatic changes in drainage basins over a period of only 18 years.

February 2, 2022February 2, 2022

Defining and Contextualising the Anthropocene

Feature Image: Huge amounts of waste symbolise the impact of human activity on the Earth System. Public domain image by Antoine Giret

Paper: The Anthropocene: Comparing Its Meaning in Geology (Chronostratigraphy) with Conceptual Approaches Arising in Other Disciplines

Authors: Jan Zalasiewicz et al.

Journal: Earth’s Future

We are now entering a new geologic time due to the planetary-scale impact of human activity. The Anthropocene is widely accepted as this new epoch, but debate is still ongoing about its scientific basis and when this new epoch began. As so many different disciplines are involved in defining and characterizing the Anthropocene, it has become difficult to properly define. A recent paper by Jan Zalasiewicz and colleagues aims to provide context as the broad subject spills over into other areas of science, art and the humanities. They emphasise that future studies should stick to the original stratigraphic and Earth System Science meaning of the term to avoid confusion around the term.

January 27, 2022January 27, 2022

The surprising effects rivers have on our atmosphere

Featured Image: Rio Bermejo meeting up with the Paraguay River, on the boarder of Formosa and Chaco Provinces. Image by Mapio. Used with permision.

Paper: Fluvial organic carbon cycling regulated by sediment transit time and mineral protection

Authors: Marisa Repasch, Joel S. Scheingross, Niels Hovius, Maarten Lupker, Hella Wittmann, Negar Haghipour, Darren R. Gröcke, Oscar Orfeo, Timothy I. Eglinton, and Dirk Sachse

In our current era of rapid climate change, it is critical we understand how every aspect of the Earth system affects carbon cycling. New work by Marisa Repasch and colleagues shows that rivers, under the right conditions, might be able to sequester more carbon in the sediments than released into the atmosphere. However, these findings may reveal how human impacts to rivers will likely increase the amount of carbon released to the atmosphere.

January 20, 2022January 20, 2022

Hunting for phosphorus on early Earth

Featured Image: A sample of the mineral schreibersite, a possible source of meteoric phosphorus. CC-BY 3.0, via Wikimedia commons.

Paper: Phosphorus mineral evolution and prebiotic chemistry: From minerals to microbes

Authors: Craig R. Walton, Oliver Shorttle, Frances E. Jenner, Helen M. Williams, Joshua Golden, Shaunna M. Morrison, Robert T. Downs, Aubrey Zerkle, Robert M. Hazen, Matthew Pasek

With a swift strike, a match bursts into flame. Life, like the flame, burst into existence almost 4 billion years ago, and as with the sparking of the match, phosphorus was a key ingredient. Phosphorus, element 15, is at the center of energy production in cells, forms cell walls, and provides the backbone for DNA.

January 13, 2022January 13, 2022

It’s magnetic! Probing the predictability of ancient rainfall using a mountainous ridge of red stone

Featured image: From Fig. 1 in Ao et al. (2021). An image of the Late Oligocene-age red mudstone that is the subject of this study, between bracketing sandstone sections. This mudstone outcrop (known as the Duittingou section) is located in the Lanzhou Basin, China, in the northeastern Tibetan Plateau. Image licensed under CC BY-NC.

Paper: Eccentricity-paced monsoon variability on the northeastern Tibetan Plateau in the Late Oligocene high CO₂ world

Authors: Hong Ao, Diederik Liebrand, Mark J. Dekkers, Peng Zhang, Yougui Song, Qingsong Liu, Tara Jonell, Qiang Sun, Xinzhou Li, Xinxia Li, Xiaoke Qiang, Zhisheng An

The intensity and frequency of rainfall affects food supply around the world, the structural integrity of buildings and homes, and flooding in the impermeable “concrete jungles” of cities. However, not much is known about how rainfall has fluctuated naturally in the distant past, making it more difficult for scientists to predict how climate change will affect future precipitation. Recently, an international team of authors addressed a small part of this problem by uncovering how rainfall in Asia changed under different climates far back in time. Their scientific adventure started once they identified a particularly special rock formation in China, where invisible traces of ancient rainfall had been preserved.