Earth's longest preserved linear volcanic ridge generated by a moving Kerguelen hotspot.

Recent seismic tomography unveiled complex mantle plume structures diverging from the originally proposed single, narrow, and vertically-oriented plume conduits, which necessitates new perspectives on the mechanism of hotspot motion. While several recent endeavours have focused on Pacific hotspots' motion, knowledge of others remains limited. Here we constrain the motions of the Kerguelen hotspot within the Indian Ocean by obtaining robust Ar/Ar ages for the Ninetyeast Ridge, Earth's longest linear volcanic ridge.

Cyclic Polyhydroxy Ketones. I. Oxidation Products of Hexahydroxybenzene (Benzenehexol).

Reliable procedures are given for the preparation and purification of hexahydroxybenzene (benzenehexol), tetrahydroxy--benzoquinone, rhodizonic acid, triquinoyl (cyclohexanehexone), croconic acid, and leuconic acid (cyclopentanepentone). Certain derivatives and color tests, as well as infrared and ultraviolet spectra, are reported for their identification.