Anti-phase variation of long eccentricity and precipitation in inland Asia during the middle Miocene Climatic Optimum (MMCO) - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

Anti-phase variation of long eccentricity and precipitation in inland Asia during the middle Miocene Climatic Optimum (MMCO)

Résumé

The mechanisms and pace of orbital forcing on precipitation in inland Asia during the Cenozoic remain poorly understood. Many previous studies have shown a consistent signal of long eccentricity (405 kyr) on precipitation records of central China that are younger than ~11 Ma. These studies suggest that variations of rainfall amount were controlled by Northern Hemisphere summer insolation, with peak of precipitation associated with eccentricity maxima. We report here multiple records dating back to the middle Miocene Climatic Optimum (MMCO, ~14-17 Ma ago) that show the exact opposite, including a detailed record from a new section in the Qaidam Basin, dated by a combination of magnetostratigraphy, U-Pb geochronology and apatite low-temperature thermochronology. Our records display dominant 405 kyr wet-dry cycles, but the wetter intervals correspond to eccentricity minima and ice-volume maxima during the MMCO. These results question the origin (monsoonal or westerly-derived?) of the precipitation reaching central China during Greenhouse episodes and the mechanisms enhancing monsoonal penetration inland Asia; they indicate that higher atmospheric pCO2 significantly impacts East Asian monsoonal circulation and its response to orbital forcing.
Fichier non déposé

Dates et versions

insu-04187764 , version 1 (25-08-2023)

Identifiants

  • HAL Id : insu-04187764 , version 1

Citer

Zhongbao Zhang, Alexis Licht, Nathan Cogné, Anta-Clarisse Sarr. Anti-phase variation of long eccentricity and precipitation in inland Asia during the middle Miocene Climatic Optimum (MMCO). Goldschmidt Conference 2023, Jul 2023, Lyon, France. ⟨insu-04187764⟩
32 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More