TY - JOUR

T1 - Formation and paleoenvironment of rhizoliths of Shiyang River Basin, Tengeri Desert, NW China

AU - Sun, Qingfeng

AU - Xue, Wenhui

AU - Zamanian, Kazem

AU - Colin, Christophe

AU - Duchamp-Alphonse, Stéphanie

AU - Pei, Wentao

N1 - Funding information: We sincerely thank Professor Jocelyn Barbarand and Dr Wang Pu for photographing the pictures under the microscope; Professor Jocelyn Barbarand for CL help; Dr Yaoxia Yang for help on the SEM; and Professor Ling Lijun for taking photos of the samples. We also thank Professor Jiawu Zhang and Professor Yaowen Xie for their assistance with the field work. We are grateful to the journal Editor-in-Chief Min-Te Chen and two anonymous reviewers for their thoughtful and constructive reviews and detail corrections. The research was supported by the Natural Science Foundation of China (Grant No. 41561046 ).

PY - 2019/1/30

Y1 - 2019/1/30

N2 - Rhizoliths found in bed of the late Quaternary paleolake Zhuyezhe, Minqin Basin, central Tengeri Desert, NW China were studied. Vegetation coverage is present at some locations in the paleolake area although, much of the bed area is covered with moving dunes. Rhizoliths are occasionally eroded out and exposed to the air. The morphology of the rhizoliths resembles singular or branching carbonated tubules which are hollow in their central part. The rhizoliths are black to grey, and are broken and scattered randomly on the sand surface of the lake bed. The lacustrine deposits are black greenish silt or silty clay with a large quantity of white petite lake snail shells. The possible plant types, sources and formation conditions of carbon dioxide and calcium, the sedimentary and diagenetic environments, and the process of rhizolith formation were discussed via examining rhizoliths macromorphology, studying the micromorphology and mineralogy by microscopy, cathodoluminescence and scanning electron microscope, and studying the chemical compositions of cementing minerals and fragments by energy dispersive X-ray spectra. The original roots of the rhizoliths belong to hydrophytes, such as Typha latifolia, Scirpus maritimus and Carex stenophylla. Lake snails and previous pollen data indicate that the rhizoliths formed in a sedimentary environment of shallow fresh water lake like marginal or palustrine areas during the Holocene. Shallow lake water disturbance by desert wind above the loose sandy sediment or soil was favoring the rhizoliths formation. A continuous supply of oxygen through water disturbance led to complete oxidation of roots and producing carbon dioxide. Dissolution of CO 2 in water and so, carbonic acid production resulted in minerals weathering such as feldspar and primary carbonate particles and the release of K + and Ca 2+ ions. At presence of CO 2 and Ca 2+ saturated in the pore water around the roots of hydrophytes within the sediments or soil, carbonate precipitation occurred around the root channel and led to rhizoliths formation as tubules. The petrifaction process therefore, has happened in margin of the paleolake with shallow water and weak redox condition, which implies the suitability of rhizolith for reconstructing paleoenvironment.

AB - Rhizoliths found in bed of the late Quaternary paleolake Zhuyezhe, Minqin Basin, central Tengeri Desert, NW China were studied. Vegetation coverage is present at some locations in the paleolake area although, much of the bed area is covered with moving dunes. Rhizoliths are occasionally eroded out and exposed to the air. The morphology of the rhizoliths resembles singular or branching carbonated tubules which are hollow in their central part. The rhizoliths are black to grey, and are broken and scattered randomly on the sand surface of the lake bed. The lacustrine deposits are black greenish silt or silty clay with a large quantity of white petite lake snail shells. The possible plant types, sources and formation conditions of carbon dioxide and calcium, the sedimentary and diagenetic environments, and the process of rhizolith formation were discussed via examining rhizoliths macromorphology, studying the micromorphology and mineralogy by microscopy, cathodoluminescence and scanning electron microscope, and studying the chemical compositions of cementing minerals and fragments by energy dispersive X-ray spectra. The original roots of the rhizoliths belong to hydrophytes, such as Typha latifolia, Scirpus maritimus and Carex stenophylla. Lake snails and previous pollen data indicate that the rhizoliths formed in a sedimentary environment of shallow fresh water lake like marginal or palustrine areas during the Holocene. Shallow lake water disturbance by desert wind above the loose sandy sediment or soil was favoring the rhizoliths formation. A continuous supply of oxygen through water disturbance led to complete oxidation of roots and producing carbon dioxide. Dissolution of CO 2 in water and so, carbonic acid production resulted in minerals weathering such as feldspar and primary carbonate particles and the release of K + and Ca 2+ ions. At presence of CO 2 and Ca 2+ saturated in the pore water around the roots of hydrophytes within the sediments or soil, carbonate precipitation occurred around the root channel and led to rhizoliths formation as tubules. The petrifaction process therefore, has happened in margin of the paleolake with shallow water and weak redox condition, which implies the suitability of rhizolith for reconstructing paleoenvironment.

KW - Mineral weathering

KW - Paleoenvironment

KW - Paleolake

KW - Rhizolith formation mechanism

KW - Rhizoliths

KW - Root decomposition

UR - http://www.scopus.com/inward/record.url?scp=85050378734&partnerID=8YFLogxK

U2 - 10.1016/j.quaint.2018.06.046

DO - 10.1016/j.quaint.2018.06.046

M3 - Article

AN - SCOPUS:85050378734

VL - 502

SP - 246

EP - 257

JO - Quaternary international

JF - Quaternary international

SN - 1040-6182

ER -