TY - JOUR

T1 - Carbonate crusts of Paleolake Zhuyeze, Tengeri Desert, China

T2 - Formation mechanism and paleoenvironmental implications

AU - Sun, Qingfeng

AU - Zamanian, Kazem

AU - Li, Yanrong

AU - Wang, Hong

AU - Colin, Christophe

AU - Sun, Haixia

N1 - Funding information: We would like to thank Dr Yaoxia Yang, Northwest University, for providing assistance on SEM. The authors are greatly indebted to the anonymous reviewers and the Editor-in-Chief, Professor Kolfschoten, for their constructive comments that improved the manuscript. The research was supported by the Natural Science Foundation of China (Grant No. 41561046 ). We would like to thank Dr Yaoxia Yang, Northwest University, for providing assistance on SEM. The authors are greatly indebted to the anonymous reviewers and the Editor-in-Chief, Professor Kolfschoten, for their constructive comments that improved the manuscript. The research was supported by the Natural Science Foundation of China (Grant No. 41561046).

PY - 2019/11/10

Y1 - 2019/11/10

N2 - Carbonate crusts with unusual morphologies are scattered on the Holocene sand surface, i.e., dunes, which cover the Paleolake Zhuyeze bed in the Tengeri Desert, China. Two types of the crusts were identified. The first type contained fossilized wrinkles of plant root cortex, while the second type consisted of hollow chambers without the wrinkle features. Optical microscopy, scanning electron microscopy and cathodoluminescence analyses were performed to investigate the mineralogy and geochemistry of the crusts. Fossilized cortex texture imprints on the first type of crusts suggested that the crusts formed around the deceased rhizomes of reeds (Phragmites communis) as the nuclei of encrustation. Weakly oxidizing soil–sediment with rhizome was a prerequisite, which was favorable for rhizome decomposition to produce sufficient CO2 and HCO3 − and generate carbonate minerals of encrustation on rhizome surfaces, with lake water as the main Ca2+ supply. A conceptual formation mechanism of the encrustation was conjectured. Similar to the formation mechanism of the first type, another type of crusts with chambers and without fossilized imprints of the cortex textures formed around the spherical rhizomes of Scirpus maritimus. The crust characteristics and other evidence suggested that the lake water was fresh; water plants, such as P. communis and S. maritimus, and snails previously inhabited the water; and encrustation reflected a stable, slow-oxidizing soil–sediment environment. These desert crusts provided insights to study paleoecology, paleohydrology and water-soil/sediment interface environment in the paleolake.

AB - Carbonate crusts with unusual morphologies are scattered on the Holocene sand surface, i.e., dunes, which cover the Paleolake Zhuyeze bed in the Tengeri Desert, China. Two types of the crusts were identified. The first type contained fossilized wrinkles of plant root cortex, while the second type consisted of hollow chambers without the wrinkle features. Optical microscopy, scanning electron microscopy and cathodoluminescence analyses were performed to investigate the mineralogy and geochemistry of the crusts. Fossilized cortex texture imprints on the first type of crusts suggested that the crusts formed around the deceased rhizomes of reeds (Phragmites communis) as the nuclei of encrustation. Weakly oxidizing soil–sediment with rhizome was a prerequisite, which was favorable for rhizome decomposition to produce sufficient CO2 and HCO3 − and generate carbonate minerals of encrustation on rhizome surfaces, with lake water as the main Ca2+ supply. A conceptual formation mechanism of the encrustation was conjectured. Similar to the formation mechanism of the first type, another type of crusts with chambers and without fossilized imprints of the cortex textures formed around the spherical rhizomes of Scirpus maritimus. The crust characteristics and other evidence suggested that the lake water was fresh; water plants, such as P. communis and S. maritimus, and snails previously inhabited the water; and encrustation reflected a stable, slow-oxidizing soil–sediment environment. These desert crusts provided insights to study paleoecology, paleohydrology and water-soil/sediment interface environment in the paleolake.

KW - Aquatic plant roots

KW - Carbonate crusts

KW - Encrustation mechanism

KW - Paleoenvironment

KW - Paleolake

KW - Soil and sediment

UR - http://www.scopus.com/inward/record.url?scp=85075839780&partnerID=8YFLogxK

U2 - 10.1016/j.quaint.2019.11.030

DO - 10.1016/j.quaint.2019.11.030

M3 - Article

AN - SCOPUS:85075839780

VL - 532

SP - 157

EP - 165

JO - Quaternary international

JF - Quaternary international

SN - 1040-6182

ER -