Preprints
https://doi.org/10.5194/egusphere-2024-1648
https://doi.org/10.5194/egusphere-2024-1648
14 Jun 2024
 | 14 Jun 2024
Status: this preprint is open for discussion and under review for Climate of the Past (CP).

Quantitative reconstruction of past monsoon precipitation based on tetraether membrane lipids in Chinese loess

Jingjing Guo, Martin Ziegler, Louise Fuchs, Youbin Sun, and Francien Peterse

Abstract. Variations in the oxygen isotope composition (δ18O) of cave speleothems and numerous proxy records from loess-paleosol sequences have revealed past variations in East Asian monsoon (EAM) intensity. However, challenges persist in reconstructing precipitation changes quantitatively. Here, we use the positive relationship between the degree of cyclization (DC) of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in modern surface soils from the Chinese loess Plateau (CLP) and mean annual precipitation (MAP) to quantify past monsoon precipitation changes on the CLP. We present a new ~130,000-year long DC-based MAP record for the Yuanbao section on the western edge of CLP, which closely tracks the orbital- and millennial-scale variations in both the speleothem δ18O record and the hydrogen isotope composition of plant waxes (δ2Hwax) from the same section. Combing our new data with existing brGDGT records from other CLP sites reveals a spatial gradient in MAP that is most pronounced during glacials, when the western CLP experiences more arid conditions and receives up to ~250 mm less precipitation than in the southeast, whereas MAP is ~850 mm across the CLP during the Holocene optimum. Furthermore, the DC records show that precipitation amount on the CLP varies at the precession as well as obliquity scale, as opposed to the primarily precession scale variations in speleothem δ18O and δ2Hwax at Yuanbao, and the 100-kyr cycle in other loess proxies such as magnetic susceptibility, which rather indicates the relative intensity of the EAM. At the precession scale, the DC record is in phase with δ2Hwax from same section as well as the speleothem δ18O record, which supports the hypothesis that monsoon precipitation is driven by northern hemisphere summer insolation.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Jingjing Guo, Martin Ziegler, Louise Fuchs, Youbin Sun, and Francien Peterse

Status: open (until 04 Sep 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Jingjing Guo, Martin Ziegler, Louise Fuchs, Youbin Sun, and Francien Peterse
Jingjing Guo, Martin Ziegler, Louise Fuchs, Youbin Sun, and Francien Peterse

Viewed

Total article views: 271 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
200 56 15 271 27 10 12
  • HTML: 200
  • PDF: 56
  • XML: 15
  • Total: 271
  • Supplement: 27
  • BibTeX: 10
  • EndNote: 12
Views and downloads (calculated since 14 Jun 2024)
Cumulative views and downloads (calculated since 14 Jun 2024)

Viewed (geographical distribution)

Total article views: 263 (including HTML, PDF, and XML) Thereof 263 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 21 Jul 2024
Download
Short summary
In this study, we use the distribution of soil bacterial membrane lipids stored on the Chinese Loess Plateau (CLP) to quantitatively reconstruct variations in precipitation amount over the past 130 kyr. The precipitation record shows orbital- and millennial-scale variations and varies at precession and obliquity scale. The application of this precipitation proxy across the CLP indicates a more pronounced spatial gradient during glacials, when the western CLP experiences more arid conditions.