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Studies of geochemical proxies, such as carbonate δ18O and TEX 86 , show that the Earth's climate has changed significantly during the Cretaceous Period. However, knowledge about the sea surface temperature (SST) history of the eastern Tethys is limited. Based on the calcareous nannofossil record of the Nirang section, Tethys Himalayas, this paper attempts to establish the biostratigraphic framework and SST evolution of the Cretaceous Period in the southern Tibet. A total of 131 species were identified from the studied succession. Twelve bioevents were recognized, allowing for early Albian to the early Campanian (CC8 to CC18 biozones) in the section. Meanwhile, a disconformity within 81–71 Ma was also identified. The SST evolution was analysed by the calcareous nannofossils modified temperature index (mTI), and the results reveal that the long-term SST changes in the Tethys Himalayas of southern Tibet experienced progressive warming from the early Albian to the early Turonian and the warm interval persisted until the early Campanian. Short-term warming and cooling events, e.g., rapid warming in the early and late Albian, subsequent cooling in the latest Albian and peak warmth at the Cenomanian–Turonian transition, are also recorded in the study area. The SST history of the Albian-Cenomanian in the eastern Tethys can be well correlated to the western Tethys (central Italy). However, the compilation of TEX 86 data indicates substantial global cooling during the Coniacian to Campanian. This study suggests that the northward drift of the Indian continent towards the equator is likely to be responsible for the sustained warmth in the Tethys Himalayas from the middle Turonian to the early Campanian. • Calcareous nannofossil biozones of Albian-early Campanian in Tethys Himalaya of southern Tibet is defined. • Based on mTI of nannofossils, long term history of Cretaceous palaeoclimate of eastern Tethys is reconstructed. • The SST history in Tethys Himalaya is controlled by changes of global palaeotemperature and regional palaeolatitude. [ABSTRACT FROM AUTHOR]

Abstract: A recent paper by Boulila et al. (2010) reports on orbitally-forced cycles recorded as marl-limestone alternations in one Lower Kimmeridgian section, Chateauneuf d''Oze (SE France, Tethyan domain). In an attempt to illustrate the in situ (i.e., pelagic) origin of carbonates in marls and limestones, the authors challenged the results of previous work concerning sections from other Tethyan areas of similar age, which demonstrate that nannofossil abundance is originally higher in marls than in limestones. Boulila et al. (2010) present data acquired with optical and Scanning Electron microscopes estimating nannofossil contribution to the rocks. However, their selected illustrations do not support a high contribution of the nannofossils to the carbonate fraction of their samples or their interpretation of the finest fraction of the rocks (micarbs). Furthermore, according to their data on carbonate content of the rocks, they did not analyse true marl-limestone alternations, but slightly argillaceous limestones and limestones. Boulila et al. (2010) also criticize earlier work providing a sequence stratigraphy interpretation of the Chateauneuf d''Oze section. However, contrarily to these earlier works, they did not consider platform-to-basin correlations that are essential in order to understand the sedimentary dynamics at the basin-wide scale. This comment challenges the work by Boulila et al. (2010) that largely underestimates the role of carbonate production on shallow platforms and its subsequent export basinwards as a major mechanism controlling the sedimentation in epicontinental basins. [Copyright &y& Elsevier]