Secondary coasts

All landforms, whether they are coasts or mountains, are formed and changed by geological processes. Coastlines can be divided into two large groups, based on whether their traits were primarily defined by land processes or by sea processes. Those sculpted by land processes are called primary coasts, and the ones that have been shaped by the ocean are called secondary coasts. 

Secondary coasts are areas that have been changed by marine processes. Like primary coasts, they were originally formed by processes on land, but they have been around longer than primary coasts, long enough for their appearance to be influenced by action of the sea. 

Water, waves, and currents are some of the sea forces that mold secondary coasts. Water is a great solvent that dissolves minerals in rock and soil. In addition, ocean water contains particles such as sand, small stones, and gravel that act like sandblasters, eroding structures and changing the coastline. 

Ocean forces create a variety of features on secondary coasts. The constant erosion caused by waves pounding on the shore carves out sea cliffs and caves. Just off the coast, the same wave action sculpts natural arches or flat platforms. In places where the underwater slope of the seafloor is not steep, waves and tides can deposit sediment and build an area of loose particles called a beach. In the United States, about 30 percent of the coastlines have beaches. 

A few secondary coasts owe their characteristics to marine organisms rather than to the sea s physical processes. Both plants and animals can add their own customized touches to a coast. In the tropics, small anemone-like sea animals called corals build extensive reefs along the coasts. Coral animals surround themselves with a hard skeleton of calcium. When a coral animal dies, its skeleton becomes part of an ever-growing underwater skyscraper made of living organisms atop the skeletons of dead ones. The Florida Keys, a string of islands off the tip of Florida, have coral reef coasts. 

The South and North were the two largest timber-related secondary products manufacturing regions, adding 16,350 million (41%) and 15,549 million (30%) of value, respectively, in 1991 (Table 10). The Rocky Mountain and Pacific Coast regions combined added the remaining 20%. 

Major sources of lead in Atlantic coast streams included wastes from metal-finishing industries, brass manufacturing, lead alkyl production, primary and secondary lead smelting, coal combustion, and manufacture of lead oxide. 

In this paper we present results which reconcile the widely different results just discussed ranging from a carbon aerosol dominated by secondary organic material on the one hand to a carbon aerosol composed largely of primary carbon compounds on the other. We have employed an approach which uses lead or elemental carbon as a tracer for primary emissions and combines several analysis techniques to reexamine the published ACHEX data. We also present a new data set from St. Louis which is analyzed in a similar manner to contrast the aerosol in a midwestern city with that on the California coast. 

Fiirstner and co-workers relied on a three-component Knochel-type [67] coupling to achieve the synthesis of (+)-dehydrohomoancepsenolide 136 (Scheme 12.21) [68], a secondary metabolite isolated from the gorgonian octocoral Pterogorgia citrina collected off the west coast of Puerto Rico [69]. 

Cornacya Seamount. This seamount recently was discovered, named and studied by Mascle et al. (2001). It is an about 12 Ma old volcano located SE of the southern Sardinian coast. Samples from Cornacya consist of strongly altered lavas that contain enclaves of mica-rich lamprophyres. The lavas have varied porphyritic textures with ubiquitous phenocrysts of zoned plagioclase and biotite plus some amphibole and clinopyroxene that are surrounded by a glass-rich matrix containing minor Na-rich plagioclase, anorthoclase, biotite and secondary products. Accessory minerals include Fe-Ti oxides, apatite and zircon. The lamprophyric enclaves are por-... 

Eutrophication Processes in Coastal Systems Origin and Succession of Plankton Blooms and Effects on Secondary Production in Gulf Coast Estuaries, Robert J. Livingston Handbook of Marine Mineral Deposits, David S. Cronan Handbook for Restoring Tidal Wetlands, Joy B. Zedler Intertidal Deposits River Mouths, Tidal Flats, and Coastal Lagoons, Doeke Eisma... 

Franks and Forester (1984) have discussed this mechanism in detail for Gulf Coast sediments, with particular emphasis on pre- and post-secondary porosity mineral assemblages. For many localities they found strikingly similar mineral assemblages (Table 8.1). Early carbonate cements had precipitation temperatures in the range of 40° to 75°C. Quartz overgrowths were observed to precipitate... 

Franks S.G. and Forester R.W. (1984) Relationships among secondary porosity, pore-fluid chemistry and carbon dioxide, Texas Gulf Coast. In Clastic Diagenesis (eds. D.A. McDonald and R.C. Surdam), pp. 63-79. AAPG, Tulsa, OK. 

Klass M.J., Kersey D.G., Berg R.R. and Tieh T.T. (1981) Diagenesis and secondary porosity in Vicksburg Sandstones, McAllen Ranch Field, Hidalgo County, Texas. Trans.-Gulf Coast Assoc. Geol. Socs. 31, 115-123. 

Lundegard P.D., Land L.S. and Galloway W.E. (1984) Problem of secondary porosity Frio Formation (Oligocene), Texas Gulf Coast. Geology 12, 399-402. 

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