This autobiography covers the past 55 years of my research in geochemistry. I try to show how chemical principles can be applied to a wide variety of geological problems, ranging from iron sulfide mineralogy, to carbonate chemistry in the oceans, to silicate mineral surface chemistry during weathering, to biogeochemical changes during early diagenesis, to plants and weathering, to models for th...

The title compound, [NH3(CH2)4NH3](2+)·SiF6 (2-), is a hybrid built from an organic butane-1,4-di-ammonium dication linked to a hexa-fluoro-silicate mineral anion. Both ions posses inversion symmetry. In the anion the Si atom is located on an inversion center, while in the cation the center of inversion is situated at the mid-point of the central -CH2-CH2- bond. The Si atom is surrounded by six...

anhydrous silicate minerals (olivine is the most abundant mineral). (Bottom) Spectra of a physical mixture dominated by hydrated silicates (saponite and lizardite are the most abundant minerals). SPECTRAL CHARACTERIZATION OF ANALOG SAMPLES IN ANTICIPATION OF OSIRIS-REx’S ARRIVAL AT BENNU. K. L. Donaldson Hanna, D. L. Schrader, N. E. Bowles, B. E. Clark, E. A. Cloutis, H. C. Connolly Jr., V. E. ...

Nanomaterials are relatively new and unconventional materials with many useful properties, but their effects on biological systems are poorly understood. Nanoclay is a general term for layered mineral silicate nanoparticles that are ideally suited for use in clay-based nanocomposites. The potential biological hazards of nanoclays have not been addressed, however. Therefore, we investigated the ...

Mineralogy, microbial ecology, and mineral weathering in the subsurface are an intimately linked biogeochemical system. Although bacteria have been implicated indirectly in the accelerated weathering of minerals, it is not clear if this interaction is simply the coincidental result of microbial metabolism, or if it represents a speciŽ c strategy offering the colonizing bacteria a competitive ec...