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Coarse-fraction sediment (>63 µm) studies for Leg 151 Sites 908 and 909 have enabled us to reconstruct the paleoclimate since the early Miocene (18.0 Ma) of the Fram Strait, in order to better understand this gateway between the North Atlantic and the Arctic Ocean. Study of the grain-size distribution patterns (subfractions 63-125 µm, 125-250 µm, 250-500 µm, 500-1000 µm, and >IOOO µm plus the coarse-component composition) suggests possible seasonal ice-rafting starting as early as 14.0 Ma. Also shown is a clear signal of ice-rafting events between 10.8 and 8.6 Ma, 7.2 and 6.8 Ma, 6.3 and 5.5 Ma, and since 5.0 Ma. Evidence indicates that the initiation of the East Greenland Current took place at 10.8 Ma and is related to the reorganization and shutdown of deep-water connections in the Middle and Central American Seaways during the latest middle to late Miocene. During the Pliocene-Pleistocene, the polar front moved over Site 908, covering the area with sea ice and pack ice during the Pleistocene (between 1.9 and 1.2 Ma). The West Spitsbergen Current episodically reached the Fram Strait during the Pliocene-Pleistocene, suggesting that the Norwegian Sea was never completely covered by sea ice and pack ice in that era.

[1] The magnetic properties of tree leaves may be used to delineate the abundance and dispersal of anthropogenic airborne particulate matter (PM) in urban environments. In the city of Rome, Italy, circulating vehicles are the main source of magnetic PM, already characterized as prevalently lowcoercivity, magnetite-like particles. To further constrain the nature and origin of such magnetic particles, we carried out coupled field emission scanning electron microscopy and a variety of rock magnetic analyses on PM specimens from Quercus ilex leaves and from potential PM sources in circulating motor vehicles in Rome. Fe-rich particles are mostly 0.1-5 mm in size, with irregular shapes and moss-like surface. Particles from disk brakes and diesel and gasoline exhaust pipes show distinct compositional and magnetic hysteresis signatures, suggesting that the magnetic PM collected on tree leaves consists of a mixture of particle populations deriving mostly from the abrasion of disk brakes and, to a lesser extent, from fuel combustion residuals emitted by diesel and gasoline exhausts. The contribution of fine superparamagnetic particles to the overall magnetic assemblage has been evaluated with specific rock magnetic analyses. The combined magnetic and microtextural-compositional analyses provide an effective and original tool to characterize urban PM air pollution.