Decadal-centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous (original) (raw)
NASA/ADS
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- Katsuta, Nagayoshi ;
- Muraki, Yasushi ;
- Heimhofer, Ulrich ;
- Ichinnorov, Niiden ;
- Asahi, Hirofumi ;
- Ando, Hisao ;
- Yamamoto, Koshi ;
- Murayama, Masafumi ;
- Ohta, Tohru ;
- Yamamoto, Masanobu ;
- Ikeda, Masayuki ;
- Ishikawa, Kohki ;
- Kuma, Ryusei ;
- Hasegawa, Takashi ;
- Hasebe, Noriko ;
- Nishimoto, Shoji ;
- Yamaguchi, Koichi ;
- Abe, Fumio ;
- Tada, Ryuji ;
- Nakagawa, Takeshi
Abstract
Understanding climate variability and stability under extremely warm `greenhouse' conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123-120 Ma: late Barremian-early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000-2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard-Oeschger events) in the `intermediate glacial' state of the late Pleistocene, and in their potential analogues in the Jurassic `greenhouse'. Our findings indicate that external solar activity forcing was effective on decadal-centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous `greenhouse' period.
Publication:
Scientific Reports
Pub Date:
December 2022
DOI:
Bibcode: