The response of calcareous nannoplankton to sea surface variability at Ceara Rise during the early Pleistocene glacial-interglacial cycles
The Ceara Rise lies just beyond the edge of the Amazon River Fan and sediments from this site may record the complex interplay of different climatic systems and processes, including past changes in southern America monsoon activity, Intertropical Convergence Zone setting, different Atlantic Meridional Overturning Circulation (AMOC) strength and phytoplankton blooming triggered by Amazon River plumes. Here we investigate early Pleistocene calcareous nannoplankton at Ceara Rise, between about 1150 and 850 kiloyears ago. Our investigation shows abrupt variations in water column dynamics across glacial/interglacial cycles or, even better, linked with different AMOC modes. Dominant placoliths in…
High-frequency climate fluctuations over the last deglaciation in the Alboran Sea, Western Mediterranean: Evidence from calcareous plankton assemblages
Abstract A high resolution study, with a centennial scale resolution, has been performed on the calcareous plankton assemblage (coccolithophores and planktonic foraminifera) at Ocean Drilling Program Site 976, Alboran Sea (Western Mediterranean), focusing on the interval between 20 and 9 ka, in order to reconstruct changes in surface and subsurface water dynamics and productivity. The biotic surface water proxies integrate the extremely detailed (multi-decadal scale) geochemical data set and the pollen record already available at the core, thus providing a complete paleoenvironmental/paleoceanographic reconstruction. The results highlight the sensitivity of the calcareous plankton in record…
Holocene climate variability of the Western Mediterranean: Surface water dynamics inferred from calcareous plankton assemblages
A high-resolution study (centennial scale) has been performed on the calcareous plankton assemblage of the Holocene portion of the Ocean Drilling Program Site 976 (Alboran Sea) with the aim to identify the main changes in the surface water dynamic. The dataset also provided a seasonal foraminiferal sea surface water temperatures (SSTs), estimated using the modern analog technique SIMMAX 28, and it was compared with available geochemical and pollen data at the site. Three main climate shifts were identified as (1) the increase in abundance of Syracosphaera spp. and Turborotalita quinqueloba marks the early Holocene humid phase, during maximum summer insolation and enhanced river runoff. It i…
Integrated stratigraphy of the Oligocene pelagic sequence in the Umbria- Marche basin (north-eastern Apennines, Italy): A potential Global Stratotype Section and Point (GSSP) for the Rupelian/Chattian boundary
The Oligocene represents an important time period from a wide range of perspectives and includes signifi cant climatic and eustatic variations. The pelagic succession of the Umbria-Marche Apennines (central Italy) includes a complete and continuous sequence of marly limestones and marls, with volcaniclastic layers that enable us to construct an integrated stratigraphic framework for this time period. We present here a synthesis of detailed biostratigraphic, magnetostratigraphic, and hemostratigraphic studies, along with geochronologic results from several biotite-rich volcaniclastic layers, which provide the means for an accurate and precise radiometric calibration of the Oligocene time sca…
The Calabrian Stage redefined
The name Calabrian was introduced in the geological literature by the French stratigrapher Maurice Gignoux in 1910, and later described in his important monograph (633 pages) "Les formations marines pliocènes et quaternaires de l'Italie du sud et de la Sicile" published in 1913. Detailed data were provided on several sections (Santa Maria di Catanzaro, Caraffa, Monasterace, Palermo) and on their fossil content. The Calabrian Stage has commonly been used for over fifty years as the oldest subdivision of the Quaternary, notably in the time scales of Berggren & van Couvering (1974) and Haq & Eysinga (1987). However, after the GSSP for the Pliocene/Pleistocene boundary (P/P) was approved by INQ…