A broad west-to-east increase of many metal concentrations has been found in stream sediments during a reconnaissance investigation conducted in conjunction with geologic studies in the Santa Renia Fields and Beaver Peak 7–1/2 minute quadrangles near the northern end of the Carlin trend of gold deposits in the Tuscarora Mountains. This regional increase in metal concentrations coincides with a dramatic change in landform wherein high concentrations of metals in stream sediments appear to correlate directly with areas of high elevations and steep slopes in the Beaver Peak quadrangle. Robust erosion combined with high flow rates in streams from these higher elevations are envisaged to have contributed significantly to increased metal concentrations in the stream sediments by an enhanced presence of minerals with high specific gravities and a correspondingly diminished presence of minerals with low specific gravities. Minerals with low specific gravities probably have been referentially flushed down stream because of high transporting capacities for sediment by streams in the Beaver Peak quadrangle. In addition, the Carlin trend, a generally northwest-alignment of gold deposits in the Santa Renia Fields quadrangle, is well outlined by arsenic concentrations that include a maximum of approximately 54 parts per million. Further, a weakly developed distal-to-proximal metal zonation towards these gold deposits appears to be defined respectively in plots showing distributions of thallium, arsenic, antimony, and zinc. A broad area of high metal concentrations—including sharply elevated abundances of Ag, As, Au, Cd, Co, Cu, Mn, Ni, P, Sb, Sc, Te, V, and especially Zn—near the southeast corner of the Beaver Peak quadrangle primarily could be the result of stratiform mineralized rocks in the Ordovician Vinini Formation or Devonian Slaven Chert, or the result of a subsequent Mesozoic or Tertiary epigenetic overprint. <...>

Groundwater geochemistry is the science that explores the processes controlling the chemical composition of groundwater, the groundwater quality. The groundwater quality influences the use of this resource. Groundwater may contain hazardous substances that affect health when consumed or which deteriorate the environment when the water is thoughtlessly spilled at the surface. The groundwater quality may change during the exploitation or it may be affected by human activities of which the impact is not always immediately evident.

The modern geologist with no knowledge of geochemistry will be severely limited. Indeed, geochemistry now pervades the discipline—providing the basis for measurement of geologic time, allowing critical insights into the Earth’s inaccessible interior, aiding in the exploration for economic resources, understanding how we are altering our environment, and unraveling the complex workings of geochemical systems on the Earth and its neighboring planets. Geochemical reasoning reveals both processes and pathways, as the book’s title implies.

Бониниты во времени и пространстве: петрогенезис и геодинамические обстановки образования

Длиннопериодные изменения в соотношении процессов тектоно-плитного и мантийно-плюмового происхождения в докембрии

Раннепалеозойский базитовый магматизм на северо-востоке Сибирского кратона

Неотектоника Охотского моря

Строение и история абиссальных холмов северо-западной плиты Пацифики по данным непрерывного сейсмического профилирования и сейсмостратиграфии