Details

Autor(en) / Beteiligte

• Ma, Yan
• Zheng, Dewen
• Zhang, Huiping
• Pang, Jianzhang
• Wang, Weitao
• Wang, Yizhou
• Wu, Ying
• He, Huaiyu
• Stuart, Finlay M.
• Xu, Sheng

Titel

Plio‐Pleistocene Establishment of Irtysh River in Junggar, Northwest China: Implications for Siberian‐Arctic River System Evolution and Resulting Climate Impact

Ist Teil von

• Geophysical research letters, 2021-06, Vol.48 (12), p.n/a

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The influence of Siberian freshwater input to the Arctic Ocean on Northern Hemisphere ice‐sheet expansions remains poorly known due to the incomplete geologic record of Siberian‐Arctic river systems during the late Pliocene. The Irtysh River is a major Siberian river, rising from the Altay Mountains, northwestern China, and flowing 4,282 km before joining the Ob River. Here, we present new field evidence and chronological data from a combination of cosmogenic 21Ne and 26Al/10Be measurements that constrain the establishment of the Irtysh River to ca. 2.77+0.39/‐0.33 Ma. These first quantitative chronological results, together with previous sedimentological, geomorphological, and geochemical evidence, support a young Siberian‐Arctic river system. Its coincidence with the late Pliocene ice‐sheet expansions in the Northern Hemisphere implies a profound impact of Siberian freshwater input to the Arctic on the major ice advances that significantly affected global oceanographic and climatic systems. Plain Language Summary Siberian rivers presently contribute ∼80% of total river discharge to the Arctic Ocean, which has a remarkable effect on decreasing ocean surface salinity and promoting rapid ice‐sheet expansions by a series of ice‐albedo feedbacks. Although the Siberian‐Arctic river system is thought to postdate the late Pliocene on the basis of sedimentological, geomorphological, and geochemical evidence, the profound impact of Siberian freshwater input on the late Pliocene ice‐sheet expansions in Northern Hemisphere remains speculative due to lack of precise chronological constraints on its formation. The Irtysh River is a major Siberian‐Arctic river, rising from the Altay Mountains in northwest China and flowing ∼4,282 km before merging with Ob River. In this work, we present new field evidence and chronological data from cosmogenic 21Ne and 26Al/10Be that constrain the establishment of the Irtysh River to ca. 2.8 Ma. The timing of its establishment is consistent with previous studies, and supports a young age for Siberian‐Arctic rivers. The coincidence of Arctic river formation in Siberia with a major ice advance in the Northern Hemisphere implies a profound impact of Siberian freshwater input to the Arctic on the late Pliocene ice‐sheet expansions that affected global oceanographic and climatic systems. Key Points We have constrained the establishment of a major Siberian river‐the Irtysh River‐to ca. 2.8 Ma by a combination of 21Ne and 26Al/10Be The timing of the Irtysh's establishment provides radioisotopic evidence for a geologically young Siberian‐Arctic river system This work supports a profound impact of Siberian freshwater input to Arctic on Northern Hemisphere ice‐sheet expansions during late Pliocene