GEOSCIENCES BY PETER J. SMITH Department of Earth Sciences Open University Milton Keynes, U.K. " A recent redetermination of solar composition showed that the Sun’s Fe abundance is 40% higher than previously thought and that Fe/Si and Ca/Al atomic ratios are 30% to 40% higher than chrondritic values. These new data require a fundamental re-evaluation of the. composition of the Earth’s mantle, which is likely to be chemically layered. The lower mantle, in particular, must be much r

GEOSCIENCES BY PETER J. SMITH Department of Earth Sciences Open University Milton Keynes, U.K. " A recent redetermination of solar composition showed that the Sun’s Fe abundance is 40% higher than previously thought and that Fe/Si and Ca/A1 atomic ratios are 30% to 40% higher than chrondritic values. These new data require a fundamental re-evaluation of the composition of the Earth’s mantle, which is likely to be chemically layered. The lower mantle, in particular, must be much r

GEOSCIENCES BY PETER J. SMITH Department of Earth Sciences Open University Milton Keynes, U.K. " Seismic reflection studies in the North Atlantic, southwest of Bermuda, show that the oceanic crust is not as uniform as hitherto supposed. In particular, dipping reflectors in the lower crust indicate either major fault zones or, more probably, chemical signatures of magma chambers once active on the mid-Atlantic ridge, note the authors of a new study. J. McCarthy, J.C. Mutter, J.L. Morton, N.H.

GEOSCIENCES BY PETER J. SMITH Department of Earth Sciences Open University Milton Keynes, U.K. " The absence of Hadean sediments at the Earth’s surface need not mean that they were never produced. They could all have been subducted along with the igneous crust after being mixed with dense meteorite impact debris. A.F.K. van Groos, “Weathering, the carbon cycle, and the differentiation of the continental crust and mantle,” Journal of Geophysical Research, 93 (B8), 8952-8, 1

BY PETER J. SMITH Department of Earth Sciences Open University Milton Keynes, U.K. " Because there has been no great earthquake in the Shumagin Islands area of the Aleutian Trench since at least 1917, the region is regarded as having high seismic potentiaL However, no strain accumulation was detected during 1980-87, suggesting that the seismic danger has been overestimated. M. Lisowaki, J.C. Strange, W.H. Prescott, W.K. Gross, “Absence of strain accumulation in the Shumagin seismic gap,

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The three-day meeting on the origin of the granites that opens in Edinburgh on September 14 is billed as a symposium celebrating the bicentenary of the work of James Hutton. But who is this James Hutton? Could it possibly be that same James Hutton whose name was invoked at another conference but a decade or so ago, the Hutton often referred to as “the father of geology”? Well, yes and no—or rather, yes, yes and no—and thereby hangs a (tragic?) tale. The James Hutton o