(Table 1) Summary of general lithology in IODP Exp302 cores ...

• Main Author: St. John, Kristen E Kudless
• Format: Dataset
• Language: English
• Published: PANGAEA 2010
• Subjects: Lithology/composition/facies; Depth, composite revised bottom; Depth, composite revised top; Age, minimum/young; Age, maximum/old; Sedimentation rate; Sample comment; Density, dry bulk; Comment; Composite Core; Visual description; see comment; Calculated; Exp302; CCGS Captain Molly Kool Vidar Viking; Integrated Ocean Drilling Program / International Ocean Discovery Program IODP; Antarc*; Antarctic; Lomonosov Ridge; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.734547; https://doi.pangaea.de/10.1594/PANGAEA.734547

The Cenozoic ice-rafted debris (IRD) history of the central Arctic is reconstructed utilizing the terrigenous coarse sand fraction in IODP 302 cores from 0 to 273 meters composite depth. This Holocene - middle Eocene quantitative record of terrigenous sand accumulation on the Lomonosov Ridge, along with qualitative information on grain texture and composition, confirms the interpretation that ice initiation (sea ice and glacial ice) occurred ~46 Ma in the Arctic, and provides a long-term pattern of Arctic ice expansion and decay since the middle Eocene. IRD mass accumulation rates range from 0 to 0.13 g/cm2/ka in the middle Eocene and from 0 to 0.36 g/cm2/ka in the Neogene. IRD mass accumulation rate (MAR) maxima in the Miocene and Pliocene cooccur with either glacial initiation or intensification in the sub-Arctic. The 46.25 Ma IRD onset in the central Arctic slightly precedes the earliest evidence of ice in the Antarctic, and compares in timing with a >1000 ppm decrease in atmospheric concentrations of ... : A hiatus of 2.2 ma exists between 135 and 140 r-mcd, and a 26-ma hiatus exists at 198 r-mcd [Backman et al., 2008; Frank et al., 2008]. ...