The geologic story of North America is a fascinating one. It’s also more than 4 billion years long—much more than we could ever hope to cover here. However, if you’re curious about the world around you, enjoy the big-picture perspective, and are interested in some of the processes that are constantly reshaping our planet, here’s a crash course on the basics. It’s a good place to start on your aerial tour of the continent’s most breathtaking landforms.

Macroseismic effects of the principal earthquakes occurring in the United States from 1568 through 1989 are described. Principal earthquakes are defined as those of Modified Mercalli intensity > VI or Richter magnitude > 4.5. Exceptions are the State of Alaska and the offshore areas of California, Oregon, and Washington, where the magnitude cutoff is > 5.5.

Since the arrival of European colonists in New York, the extraction of mineral wealth has been an important societal goal. Mining, then and now, provides the raw materials for consumer goods. Iron was used for cooking utensils and stoves, among other things. It was the basis for many construction projects. The availability of “hydraulic” cement was as important in the success of the Erie Canal as it is to the maintenance of the New York State Thruway. Mines provided materials to improve the standard of living of the populace. Late nineteenth century clay mines in the Hudson River Valley provided clay to make literally billions of bricks used to replace the highly flammable wooden building materials of New York City. The State of New York has, since the 1980s, ranked about fifteenth in the nation in terms of mineral value extracted annually.

Duane Allan Smith has been called many things, but no one can deny he is Colorado’s most prolific historian, surpassing even the late, great LeRoy Hafen. The Trail of Gold and Silver is Smith’s fiftieth book. The University Press of Colorado’s Timberline Books series, which features the best current work on Colorado as well as classic reprints, proudly presents this master historian’s survey of 150 years of Colorado gold and silver mining. <...>

The quaternary of the United States THE QUATERNARY PERIOD of geologic time encompasses the last ice age proper (Pleistocene Epoch) and subsequent time (Holocene or Recent Epoch). The Quaternary is unique among the geologic periods for the relative perfection of its stratigraphic record—and thus for the unmatched opportunity it affords to decipher historical details with an accuracy impossible for earlier periods. The framework of the continents even in early-Quaternary time resembled that of the present so closely that major relations of land and sea and their effects on the general circulation of the atmosphere were probably very like those of the present, except perhaps when world-wide lowering of sea level exposed continental shelves or created significant land bridges between continents and arctic islands. Reconstructions of past conditions therefore may be controlled by a geographic framework relatively easy to visualize. <...>

Освещен опыт ведущих фирм США по производству н применению взрывчатых материалов в горнодобывающих отраслях промышленности п в строительстве. Описаны техника и технология взрывных работ на открытых и подземных разработках и даны практические рекомендации по выбору типов взрывчатых веществ, изложены способы заряжания и взрывания в различных горно-геологических условиях. Приведены методики распета рациональных параметров буровзрывных работ. Особое внимание уделено производству специальных взрынных работ, в стесненных условиях и при вскрытии месторождении, а также мероприятиям по повышению беяопаспости.
Для инженерно-технических работников горнодобывающих предприятий, научно-исследовательских и проектных организаций.

This field trip is based on reconnaissance geologic mapping in the Charlottesville 10 X 2 0 quadrangle as part of a new edition of the Geologic Map of Virginia (Figure 1). The first day of the field trip will be spent examining high-rank Grenville-age basement rocks that make up the core of the Blue Ridge anticlinorium. The second day will be spent examining greenschist facies Precambrian and Early Paleozoic metasedimentary and metavolcanic cover rocks that unconformably overlie the Grenville basement and dip to the southeast, off the southeastern limb of the anticlinorium <...>

Recent quantitative studies of gneisses in the Laramie Range by Newhouse and Hagner (1947) have resulted in the idea that structure of the host rock is a dominant factor controlling the composition of gneisses and schists. The Sherman granite, which is exposed in the southern part of the Laramie Range (Fig. 1), was selected for a quantitative study for three reasons: (1) a similar study had been made by Newhouse and Hagner on associated gneissic rocks which made it possible to correlate and compare results; {'d) most of the geologic contacts were mapioed previously, and thus nearly all of the field time could be devoted to a study of the granite; and (3) the area is of batholithic dimensions and is readily accessible. The problem was to determine whether any relationship existed between structure and composition of the granite, to explain the significance of any correlation or lack of correlation discovered, and to determine the relation of the Sherman granite to the Raggedtop gneisses studied by Newhouse and Hagner. <...>