(Table 1) Summary of horizon, lithology, and paleomagnetic of ODP Hole 126-791B basaltic mousse samples

A paleomagnetic study was made on the highly vesiculated basaltic tuff breccia (the basaltic mousse) drilled by Ocean Drilling Program Leg 126 from the Izu-Bonin backarc, Sumisu Rift, to estimate the mode of its emplacement. Thirty-four 10-cm**3 minicore samples were collected from almost all the horizons of the basaltic mousse. Stepwise thermal and alternating-field demagnetization experiments show that the natural remanent magnetizations of many samples are mainly composed of a single stable component. Although remanence inclinations are not expected to be disturbed by rotary drilling, the measured inclinations of remanence show a random directional distribution as a whole. The remanence inclinations, however, show directional consistency on a smaller scale. High-density sampling and measurements from a limited interval of drilled cores, and the measurement of small disks cut from a single minicore sample show that there is directional consistency over several centimeters. Strong and stable remanent magnetization, the existence of remanence direction consistency, and the fresh lithology of the samples suggest the thermal origin of remanence. Combining the paleomagnetic results with other geological, petrographical, and paleontological characters, the Hole 791B basaltic mousse can be interpreted as a subaqueous explosion breccia produced by deep-sea pyroclastic fountaining.

Tab. 1: Palynological investigation of horizon 1961 of Kesselwandferner

Pollen analytical investigations of glacier ice from the Kesselwandferner in the Ötztal Alps, Tyrol, generally confirmed the palynologycal findings of Vareschi (1942) and brought new results. Annual layers were found which distinguish themselves by an increased content of Pl:cea pollen according to extreme Picea-blooming years. These can be used as "guiding horizons" in the firn-area of the glaciers. Long distance transport of African pollen (Ephedra) was proved. The absolute average pollen rain in 3300 m was determined by 28.000 pollen grains per year and dm**2. The investigation of fens near glaciers made it possible to determine the oscillations of the tree-line and the forest-linc and to date them by 0-14. These oscillations could be connected with moraines also dated by 0-14. Oscillations of the forest-line and thus probably glacier oscillations, too, could be determined for the period from 6700 to 6000 B.C. and the periods about 4500, 2600 and 1600 B.C.