Late cretaceous history of eolian deposition in the mid-pacific mountains, central North Pacific Ocean

Eolian dust preserved in deep-sea sediment can provide a direct historical record of global atmospheric circulation. Data from a reasonably complete Upper Cretaceous section of pelagic sediments recovered at DSDP Site 463 in the central North Pacific provides a good record of eolian activity during the time period between about 112 and 66 m.y. ago. We have isolated the eolian component from these sediments, determined its mass accumulation rate and combined these data with the mineralogy of the inorganic fraction determined by others to construct a record of eolian deposition. Volcanic input is significant during Aptian-Albian and Maastrichtian times, otherwise continentally derived minerals dominate. Mass accumulation rates of the continental eolian component range from over 500 mg/cm2/103yr during the late Albian to a low of 5 mg/cm2/103yr during Coniacian time. (For comparison, the upper Miocene to Pleistocene rate averages about 20 mg/cm2/103yr.) The temporal pattern of Late Cretaceous eolian accumulation of Site 463 generally matches known changes in sea level, suggesting that source availability is the dominant control of eolian sedimentation during that time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24203/1/0000462.pd

Clay minerals at DSDP Sites 71-511 and 71-513

The distribution of clay minerals, determined by X-ray diffraction, is given for Jurassic to Holocene sediments recovered at DSDP Sites 511 and 513 in the Southwest Atlantic. These data, plus the lithologic and paleoenvironmental information gathered by the shipboard scientists, are used to subdivide the sedimentary sequence into genetic lithologic facies labeled series, seven for Site 511 and two for Site 513. Sediments of these series reflect the main historical and paleoenvironmental events which other means of study have determined to affect this region; particularly important was the opening of the South Atlantic during the Early Cretaceous

Clay minerals in Mesozoic and Cenozoic sediments at DSDP Leg 62 Holes

The main tasks of this study were (1) identification of minerals of the clay fraction, (2) identification of clay-mineral associations in relation to stratigraphic intervals, and (3) elucidation of genetic relations of clay minerals with types of sediments and factors of sedimentation. Identification of clay minerals was carried out mainly with an X-ray diffractometer (DRON-I). X-ray diffractograms were prepared by means of CuKalpha radiation, at 35 kW and a current of 20 ma. The scanning rate was 2°/min. Oriented specimens were prepared for the <1-µm fraction (and partly for the <10-µm fraction because of insufficient core material) in three states: air-dried, saturated with glycerine, and heated at 550°C