<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">Leslie, Deborah L.</style></author><author><style face="normal" font="default" size="100%">Michael N. Gooseff</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Hunt, Allen</style></author><author><style face="normal" font="default" size="100%">Egli, Markus</style></author><author><style face="normal" font="default" size="100%">Faybishenko, Boris</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Chemical weathering in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Hydrogeology, Chemical Weathering, and Soil Formation</style></secondary-title><tertiary-title><style face="normal" font="default" size="100%">Geophysical Monograph Series</style></tertiary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">aluminosilicate weathering</style></keyword><keyword><style  face="normal" font="default" size="100%">CaCO3 dissolution/precipitation</style></keyword><keyword><style  face="normal" font="default" size="100%">chemical weathering</style></keyword><keyword><style  face="normal" font="default" size="100%">hyporheic zone</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2021</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/10.1002/9781119563952.ch11</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">257</style></number><publisher><style face="normal" font="default" size="100%">John Wiley &amp; Sons, Inc.</style></publisher><pub-location><style face="normal" font="default" size="100%">Hoboken, NJ</style></pub-location><pages><style face="normal" font="default" size="100%">205-216</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;While chemical weathering has not always been considered an active process in the McMurdo Dry Valleys (MDV), Antarctica, long‐term geochemical and hydrological investigations have provided an overall better understanding of chemical weathering in this polar desert environment. Liquid water on the landscape is limited to stream channels as well as shallow subsurface melt features, as there is no overland flow. Stream total suspended sediment loads are low, with the sources of sediment from stream channels, aeolian input, and/or from the surfaces of glaciers. MDV soils contain high concentrations of soluble salts with little clay material, but since absent of water, these soils are a minimal location of chemical weathering. Hyporheic zones exchange water during streamflow, and these areas control the stream geochemistry over various temporal scales. Hyporheic zones promote rapid aluminosilicate weathering by moving dilute glacial meltwater into intimate contact with sediment surfaces. Rapid weathering of the aluminosilicates in the streambed and hyporheic zones is the most plausible explanation for chemostasis observed in these streams, indicating that little to no catchment processes are necessary to explain the observed chemostasis in the MDV. Shallow subsurface waters with distinct geochemical signatures have much higher dissolved Si concentrations than the stream waters and indicate that they are responsible for enhanced aluminosilicate weathering in this polar desert environment. The dissolution of CaCO&lt;sub&gt;3&lt;/sub&gt; is also a major process in the hyporheic zones as generally the streams are unsaturated with respect to calcite. Cation‐exchange reactions are also important in the evolution from Na‐Cl brines to Ca‐Cl brines within the soil column, while authigenic CaCO&lt;sub&gt;3&lt;/sub&gt; can both dissolve and precipitate depending on the condition of the system. Recently, stream channel landscapes are changing due to the melting of buried ice, creating thermokarst and water track features, resulting in a sediment and solute influx to the stream.&lt;/p&gt;</style></abstract><section><style face="normal" font="default" size="100%">11</style></section></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Harmon, Russell S.</style></author><author><style face="normal" font="default" size="100%">Leslie, Deborah L.</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Geochemistry of contrasting stream types, Taylor Valley, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">GSA Bulletin</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">01/2021</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://pubs.geoscienceworld.org/gsa/gsabulletin/article/133/1-2/425/587799/Geochemistry-of-contrasting-stream-types-Taylor</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">133</style></volume><pages><style face="normal" font="default" size="100%">425-448</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The McMurdo Dry Valley region is the largest ice-free area of Antarctica. Ephemeral streams flow here during the austral summer, transporting glacial meltwater to perennially ice-covered, closed basin lakes. The chemistry of 24 Taylor Valley streams was examined over the two-decade period of monitoring from 1993 to 2014, and the geochemical behavior of two streams of contrasting physical and biological character was monitored across the seven weeks of the 2010&amp;ndash;2011 flow season. Four species dominate stream solute budgets: HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;&amp;ndash;&lt;/sup&gt;, Ca&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;, Na&lt;sup&gt;+&lt;/sup&gt;, and Cl&lt;sup&gt;&amp;ndash;&lt;/sup&gt;, with SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2&amp;ndash;&lt;/sup&gt;, Mg&lt;sup&gt;2+&lt;/sup&gt;, and K&lt;sup&gt;+&lt;/sup&gt; present in significantly lesser proportions. All streams contain dissolved silica at low concentrations. Across Taylor Valley, streams are characterized by their consistent anionic geochemical fingerprint of HCO&lt;sub&gt;3&lt;/sub&gt; &amp;gt; Cl &amp;gt; SO&lt;sub&gt;4&lt;/sub&gt;, but there is a split in cation composition between 14 streams with Ca &amp;gt; Na &amp;gt; Mg &amp;gt; K and 10 streams with Na &amp;gt; Ca &amp;gt; Mg &amp;gt; K.&lt;/p&gt;&lt;p&gt;&lt;br /&gt;Andersen Creek is a first-order proglacial stream representative of the 13 short streams that flow &amp;lt;1.5 km from source to gage. Von Guerard is representative of 11 long streams 2&amp;ndash;7 km in length characterized by extensive hyporheic zones. Both streams exhibit a strong daily cycle for solute load, temperature, dissolved oxygen, and pH, which vary in proportion to discharge. A well-expressed diurnal co-variation of pH with dissolved oxygen is observed for both streams that reflects different types of biological control. The relative consistency of Von Guerard composition over the summer flow season reflects chemostatic regulation, where water in transient storage introduced during times of high streamflow has an extended opportunity for water-sediment interaction, silicate mineral dissolution, and pore-water exchange.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1/2</style></issue></record></records></xml>