Genesis and soil environmental implications of intact in-situ rhizoliths in dunes of the Badain Jaran Desert,northwestern China  

作　　者：Qingfeng Sun Kazem Zamanian Arnaud Huguet Omid Bayat Hong Wang Hanan SBadawy 

机构地区：[1]Key Laboratory of Resource Environment and Sustainable Development of Oasis,Northwest Normal University,730070 Lanzhou,Gansu Province,Gansu,PR China [2]Key Laboratory of Eco-function Polymer Materials of the Ministry of Education,Northwest Normal University,730070 Lanzhou,Gansu,PR China [3]Institute of Soil Science,Leibniz University of Hannover,Herrenhäuser Straße 2,30419 Hannover,Germany [4]Sorbonne Université,CNRS,EPHE,UMR METIS,F-75005 Paris,PSL,France [5]Department of Soil Science,Isfahan University of Technology,84156-83111 Isfahan,Iran [6]Interdisciplinary Research Center of Earth Science Frontier,Beijing Normal University,100875 Beijing,PR China [7]Department of Geology,Faculty of Science,Beni-Suef University,62521 Beni-Suef,Egypt [8]School of Geographical Sciences,Nanjing University of Information Science and Technolog,210044,Nanjing,China

出　　处：《Acta Geochimica》2022年第5期811-822,共12页地球化学学报（英文）

基　　金：the Natural Science Foundation of China(41561046);Chinese-German Centre(Sino-German Mobility M-0069);the German Research Foundation(DFG)(ZA 1068/4-1)。

摘　　要：Desert rhizoliths are generally found as weathered,broken and scattered samples on dune field surface,but rarely insitu in their initial states buried under the soil of desert in the Badain Jaran Desert,northwest China.This study off ers an assessment of the morphological,mineralogical,and chemical properties of intact and in-situ rhizoliths found in soils of swales and depressions among dune chains.The characteristics of these rare and precious objects were assessed using optical polarizing microscopy,cathodoluminescence,scanning electronic microscopy,radiocarbon dating,and stable isotopic analyses,providing the opportunity for discussion of the rhizolith formation mechanisms and associated environmental conditions.Field and laboratory investigations showed that the in-situ intact rhizoliths were formed only in the places where Artemisia shrubs are living,and the remaining root relicts within rhizoliths belong to this species.The spatial distribution of rhizoliths also suggested that low topographic positions on a landscape provided soil moisture,and redox environments favored rhizolith formation.A semi-closed redox environment in the subsoil at swales and depressions,where water is always present,along with the sandy soil texture,facilitated fast water percolation to deeper depths and condensation.Such a soil environment not only provides water for Artemisia growth,but also for the weathering of minerals such as felspars and calcite from primary carbonates,and for the decomposition of root relicts.Furthermore,harsh climatic conditions,such as strong winds and solar radiation,led to water evaporation through dead root channels and triggered the calcification along the root relicts.The entrapped lithogenic carbonates and to a lesser extent the decomposition of Artemisia roots provided the carbon sources for the rhizoliths formation,while the weathering of soil minerals,particularly feldspars and carbonates,was the main source of Ca.Rhizoliths in the Badain Jaran desert formed relatively quickly,probably over a fe

关 键 词：Rhizoliths CALCIFICATION Leptic regosols Artemisia roots Decomposition Soil moisture 

分 类 号：P931.3[天文地球—自然地理学]