Palaeoclimate analysis of Late Cretaceous angiosperm leaf floras, James Ross Island, Antarctica
Peta A. Hayes, Jane E. Francis, David J. Cantrill, J. Alistair Crame, 2006. "Palaeoclimate analysis of Late Cretaceous angiosperm leaf floras, James Ross Island, Antarctica", Cretaceous–Tertiary High-Latitude Palaeoenvironments: James Ross Basin, Antarctica, J. E. Francis, D. Pirrie, J. A. Crame
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The fossilized remains of Cretaceous angiosperm leaves are preserved within sandstones and siltstones of the Coniacian Hidden Lake Formation (Gustav Group) and the Santonian–early Campanian Santa Marta Formation (Marambio Group) in the James Ross Basin, Antarctic Peninsula region. The leaves represent the remains of vegetation that grew at approximately 65°S on an emergent volcanic arc, now represented by the Antarctic Peninsula, and were subsequently transported and buried in marine sediments in the adjacent back-arc basin. Some of the angiosperm leaf morphotypes show similarities to leaves of living families such as Sterculiaceae, Lauraceae, Winteraceae, Cunoniaceae and Myrtaceae. Palaeoclimate analysis based on physiognomic aspects of the leaves, such as leaf-margin analysis, indicates that the mean annual temperatures for the Hidden Lake and Santa Marta formations were 13–21 °C (mean 17 °C) and 15–23 °C (mean 19 °C), respectively. The fossil plants are indicative of warm climates without extended periods of winter temperatures below freezing and with adequate moisture for growth. This period of Cretaceous warmth in Antarctica corresponds with the Cretaceous thermal maximum, an interval of peak global warmth from the Turonian to the early Campanian.
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High-latitude settings are sensitive to climatically driven palaeoenvironmental change and the resultant biotic response. Climate change through the peak interval of Cretaceous warmth, Late Cretaceous cooling, onset and expansion of the Antarctic ice sheet, and subsequently the variability of Neogene glaciation, are all recorded within the sedimentary and volcanic successions exposed within the James Ross Basin, Antarctica. This site provides the longest onshore record of Cretaceous–Tertiary sedimentary and volcanic rocks in Antarctica and is a key reference section for Cretaceous–Tertiary global change. The sedimentary succession is richly fossiliferous, yielding diverse invertebrate, vertebrate and plant fossil assemblages, allowing the reconstruction of both terrestrial and marine systems. The papers within this volume provide an overview of recent advances in the understanding of palaeoenvironmental change spanning the mid-Cretaceous to the Neogene of the James Ross Basin and related biotic change, and will be of interest to many working on Cretaceous and Tertiary palaeoenvironmental change.