DOI: 10.1016/j.earscirev.2020.103092
论文题名: A global palaeoclimatic reconstruction for the Valanginian based on clay mineralogical and geochemical data
作者: Charbonnier G. ; Duchamp-Alphonse S. ; Deconinck J.-F. ; Adatte T. ; Spangenberg J.E. ; Colin C. ; Föllmi K.B.
刊名: Earth-Science Reviews
ISSN: 128252
出版年: 2020
卷: 202 语种: 英语
英文关键词: Global reconstruction
; Hydrolysing conditions
; Palaeoclimate belt
; Temperature range
; Valanginian
; Volcanic activity
Scopus关键词: clay mineral
; Cretaceous
; geochemistry
; hydrolysis
; mineralogy
; paleoclimate
; paleolatitude
; smectite
; Atlantic Ocean
; Atlantic Ocean (North)
英文摘要: High-resolution clay mineral and δ18Ocarb analyses have been performed on three sections of Valanginian age (Early Cretaceous), from northwestern (~20–30°N) and southern (~53°S) Tethyan realms. The data have been integrated in a large set of published mineralogical (clays), and geochemical (δ18Ocarb, δ18Obivalve, δ18Olenticulina, δ18Obelemnite, and TEX86) data from 17 sections, situated between ~45°N and ~53°S. Based on this data set, we provide new insights into Valanginian climate conditions from a wide range of palaeolatitudes. We highlight climate trends within specific areas and identify main climate belts. In the Proto-North Atlantic realm (~15–17°N) large amounts of smectite together with the occurrence of palygorskite testify for a semi-arid climate belt throughout the Valanginian. Significant variations in kaolinite content in the northwestern Tethyan realm (~20 to 30°N) suggest that this realm has been more sensitive to changes in hydrological cycling and subsequent erosion and runoff processes during the early to early–late Valanginian transition interval. This time interval, that is coincident with the pronounced positive and globally recognized carbon isotope excursion (CIE; the Weissert episode), documents the wet conditions of a humid subtropical climate belt. Temperature ranges derived from δ18O records suggest climate warming by about 3–5±0.9°C in the northern hemisphere, during the Weissert episode. This is followed by a global cooling of about ca. 1–5±0.9°C in both hemispheres, during the late Valanginian. We postulate that these patterns were due to interplays between tectonic and orbital factors, which have controlled the distribution of regional palaeoclimate belts during the Valanginian. The semi-arid belt expressed in the Proto North Atlantic realm has probably been induced by its specific palaeogeographic configuration and the existence of isolated basins, which were each characterized by strong and continuous thermohaline circulation. An eccentricity paced monsoon-like system might have played a significant role in maintaining the subtropical belt around the northwestern Tethyan realm, up to the mid latitudes (~35–45°N). Superimposed on these regional processes, a widespread magmatic pulse in Paraná-Etendeka volcanic activity might have stimulated greenhouse conditions, impacting marine biota and favouring the development of a dense vegetation cover on the continent. An increase in sedimentary burial of 13C depleted organic carbon on the continents may have contributed to the progressive global positive carbon isotope excursion. In the medium term, it has also probably led to a significant decrease in atmospheric CO2, as testified by the global cooling recorded during the late Valanginian in both hemispheres and the probable concomitant extension of polar ice caps. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/158847
Appears in Collections: 气候变化与战略
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作者单位: Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, CH-1015, Switzerland; UMR CNRS 8148 GEOPS, Université Paris Sud XI, Bâtiment 504, Orsay, 91405, France; UMR CNRS 6282 Biogéosciences Université de Bourgogne/Franche-Comté, 6 Bd. Gabriel, Dijon, 21000, France; Institute of Earth Surface Dynamics, University of Lausanne, Géopolis, Lausanne, CH-1015, Switzerland
Recommended Citation:
Charbonnier G.,Duchamp-Alphonse S.,Deconinck J.-F.,et al. A global palaeoclimatic reconstruction for the Valanginian based on clay mineralogical and geochemical data[J]. Earth-Science Reviews,2020-01-01,202