Publications

This chapter discusses mercury cycling in the terrestrial landscape, including inputs from the atmosphere, accumulation in soils and vegetation, outputs in streamflow and volatilization, and effects of land disturbance. Mercury mobility in the terrestrial landscape is strongly controlled by organic matter. About 90% of the atmospheric mercury input is retained in vegetation and organic...

The southern Appalachian part of the Cambrian–Ordovician passive margin succession of the great American carbonate bank extends from the Lower Cambrian to the lower Middle Ordovician, is as much as 3.5 km (2.2 mi) thick, and has long-term subsidence rates exceeding 5 cm (2 in.)/k.y. Subsiding depocenters separated by arches controlled sediment thickness. The succession consists of five

Extended post-fledging parental care is an important aspect of parental care in birds, although little studied due to logistic difficulties. Commonly, the brood is split physically (brood division) and/or preferential care is given to a subset of the brood by one parent or the other (care division). Among gulls and tern (Laridae), males and females generally share parental activities...

In 2011, U.S. apparent consumption of strontium (contained in celestite and manufactured strontium compounds) increased markedly to 18.4 kt (20,300 st) from 10.4 kt (11,500 st) in 2010. Gross weight of imports was 34.4 kt (38,000 st), of which 76 percent originated from Mexico.

The method of emplacement and sequential deformation of major thrust zones may be deciphered by detailed geologic mapping of these important structures. Thrust fault zones may have added complexity when horse blocks are contained within them. However, these horses can be an important indicator of the fault development holding information on fault-propagation folding or fold-to-fault...

Dinocysts recovered from sediments related to the Chesapeake Bay impact structure in Virginia and the earliest Eocene suboxic environment in Maryland show strange and intriguing details of preservation. Features such as curled processes, opaque debris, breakage, microborings and cyst ghosts, among others, invite speculation about catastrophic depositional processes, rapid burial and...

The United States continues to be the world's leading producer and consumer of diatomite. Production of diatomite in the United States during 2011 was estimated to be 600 kt (661,000 st), a slight increase compared with 2010 production. The unit value of diatomite varied widely by end use in 2011. Diatomite used as a lightweight aggregate was priced at $8.82/t ($8/st), while specialty...

Ammonia was produced by 12 companies at 27 plants in 15 states in the United States during 2011. Sixty-one percent of total U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2011, U.S. producers operated at about 84 percent of their rated capacity (excluding plants...

In 2011, elemental sulfur and the byproduct sulfuric acid were produced at 109 operations in 29 states and the U.S. Virgin Islands. Total shipments were valued at about $1.6 billion. Elemental sulfur production was 8.2 Mt (9 million st); Louisiana and Texas accounted for about 53 percent of domestic production.

Four minerals represent 90 percent of the borates used by industry worldwide — the sodium borates, tincal and kernite; the calcium borate, colemanite; and the sodium-calcium borate, ulexite.

In 2010, the market appeared to bottom out with production continuing its downward trend and average unit values down for the first time since 1998.

Domestic production, consumption, exports and prices of perlite in the United States were all estimated to have decreased in 2011 compared with 2010, but not significantly. The weak economic conditions that prevailed in the United States for most of the 2011 probably accounted for these decreases. The only statistic that increased was imports, which were estimated to have risen by about...