Geological history of the Western north pacific

A considerable portion of the abyssal floor of the western North Pacific was already receiving pelagic sediment in late Jurassic time. Carbonate sediments were later replaced by abyssal clays as the basin deepened and bottom waters became more aggressive. The resulting facies boundary, which can be recognized on seismic profiles, is broadly transgressive; it ranges in age from mid-Cretaceous in the western Pacific to Oligocene in the central Pacific. Cherts are encountered at and below the major facies boundary and appear to have been formed by postdepositional processes.     

Fish fertilizer: a native north american practice?

The belief that the use of fish fertilizers originated among North American Indians, and was communicated as such by Squanto to the Plymouth settlers, has achieved the status of folklore and is therefore difficult to challenge. However, examination of the documentary evidence of Squanto's history and of native cultivation practices, and a cultural analysis of the implications of the use of fish fertilizer, have produced complementary lines of evidence. This evidence indicates that widely held beliefs about the "manner of the Indians" should be revised: Squanto's advice at Plymouth is probably best viewed as an interesting example of culture contact, one in which a native "culture-bearer" conveyed a technological idea from one group of Europeans to another.     

Microchronology and demographic evidence relating to the size of pre-columbian north american Indian populations

Recent estimates for the size of the aggregate North American Indian population in A.D. 1492 vary from about 18 million to less than 2 million. The unusually favorable archaeological characteristics of Mohawk Iroquois sites in eastern New York have allowed a detailed demographic reconstruction of one case for the period A.D. 1400 to 1776. The case indicates that exogenous epidemics did not reach the region until the 17th century and supports arguments favoring the lower populations estimates for North America as a whole.     

Composition of the ancient north american crust

Geochemical studies of Wyoming Precambrian graywackes derived from continental crust older than 3.2 x 10(9) years indicate that their source area was at least as highly differentiated as most younger Precambrian crust. The composition of this early crust (approximately that of calcium-rich granite) is not unlike that of the 2.5 to 3.2 x 10(9) year old North American crust. Limited geochemical data suggest that the composition of North America may not have changed significantly during the last 3.0 to 3.5 x 10(9) years.     

Origins of the 1988 north american drought

The 1988 summer drought in the United States was the most extensive in many years. Because the drought developed in different places at different times, not all regional effects can be traced to the same cause. Along the West Coast and in the northwestern United States drought conditions developed during 1987 in association with the 1986 to 1987 El Ni?o in the tropical Pacific Ocean. Record low rainfalls from April to June 1988 led to rapid development of drought in the North Central United States. Strong anticyclonic conditions and a northward displaced jet stream in the upper atmosphere over North America throughout this period were only part of pronounced and distinctive wavetrain of anomalies in the atmospheric circulation that appeared to emanate from the tropical Pacific. Below average sea surface temperatures along the equator in the Pacific in the northern spring of 1988, combined with warmer than normal water from 10 degrees to 20 degrees N, led to a northward displaced but still active intertropical convergence zone (ITCZ) southeast of Hawaii. Results from a steady-state planetarywave atmospheric model indicate that the atmospheric heating anomalies associated with the displaced ITCZ can force an anomalous wavetrain across North America similar to that observed. Land surface processes probably contributed to the severity and persistence of the drought; however, the large-scale atmospheric circulation perturbations associated with natural variations in the coupled atmosphere-ocean system in the tropical Pacific were most likely the primary cause.     

Export of north american ozone pollution to the north atlantic ocean

Measurement of the levels of ozone and carbon monoxide (a tracer of anthropogenic pollution) at three surface sites on the Atlantic coast of Canada allow the estimation of the amount of ozone photochemically produced from anthropogenic precursors over North America and transported to the lower troposphere over the temperate North Atlantic Ocean. This amount is greater than that injected from the stratosphere, the primary natural source of ozone. This conclusion supports the contention that ozone derived from anthropogenic pollution has a hemisphere-wide effect at northern temperate latitudes.     

A cheetah-like cat in the north american pleistocene

The discovery of abundant skeletal remains of Felis trumani from a late Pleistocene deposit in Wyoming shows that it was as highly modified for cursorial locomotion as the cheetah (Acinonyx). Several other Pleistocene felids that have been regarded as pumas seem to be related forms. The late Pleistocene fauna of the Big Horn Basin in Wyoming is dominated by cursorial taxa.     

Fossil counterparts of giant penguins from the north pacific

New fossils of giant, flightless penguinlike birds have been found in late Oligocene and early Miocene rocks in Japan and in the state of Washington. These birds belong to the order Pelecaniformes, in the extinct family Plotopteridae, previously known by a single fragment of bone from California. Hindlimb and pelvic morphology is most similar to that of Recent anhingas, but the wing is paddlelike and remarkably convergent toward penguins and flightless auks. Both the Plotopteridae and the giant penguins became extinct by the middle Miocene, possibly because of competition from seals and porpoises.     

Ocean eddies generated by seamounts in the north pacific

Small-scale (diameters of about 37 kilometers) fluctuations in dynamic topography north of Hawaii along 158 degrees W are well correlated with upstream seamounts. The fluctuations are subsurface but are manifested as baroclinic eddies at the sea surface. These eddies are confirmed by direct observations and supported by theoretical considerations. The eddies cause small-scale variability in the currents and hydrographic structures in this area, and they should be considered in any sampling programs of the region.     

Forests in the long sweep of american history

The role of forests in the American society and economy has changed greatly over the past 200 years, as is evidenced by data on acreage in forests, on volume of standing timber, on amount of annual wood growth, on amounts and form of wood utilization, and on prices for forest products. The two most dramatic facts in a long history of forest utilization have been the near fourfold increase in annual wood growth in the past 60 years and the persistent and major underestimate by the U.S. Forest Service of the wood production potential of American forests.     

Mesoscale ocean eddies in the north pacific: westward propagation

A set of subsurface temperature measurements in the trade wind region northeast of Hawaii reveals large perturbations about the mean state, with zonal wavelengths of 480 kilometers. The perturbations are identified as mesoscale baroclinic eddies, and they appear to drift westward at a rate of 4.7 +/- 2.0 centimeters per second. The large-scale ( 1000 kilometers) baroclinic flow at a depth of 200 meters is 1.5 +/- 0.7 centimeters per second, also toward the west, and comparable in magnitude with the eddy drift velocity; this finding suggests that the eddy drift is strongly influenced by the large-scale flow. Mesoscale eddies have been discovered in the tropical and subtropical Atlantic Ocean. Their existence in the Pacific Ocean is now confirmed.     

Acantharian fluxes and strontium to chlorinity ratios in the north pacific ocean

Data on particulate strontium sulfate fluxes and strontium to chlorinity ratios were compared to provide insights into the strontium cycle of the North Pacific. Freedrifting sediment traps were used to derive large particle fluxes between depths of 100 and 3500 meters in the eastern and western North Pacific Ocean. Flux data revealed substantial quantities of acantharian skeletons and cysts (both made of strontium sulfate) settling through the upper kilometer of the water column. The greatest fluxes of celestite were detected at 400 meters. Minimal to nondetectable fluxes noted at and below 900 meters provide evidence that by this horizon, the majority of acantharian specimens had dissolved, thereby contributing to the pool of dissolved strontium. Growth and subsequent dissolution of acantharians in the upper kilometer are qualitatively consistent with the well-developed minimum and maximum strontium to chlorinity ratios that are consistently noted in these waters. These fluxes of particulate strontium and model calculations for fluxes of dissolved strontium indicate that acantharians play an important role in the ocean's strontium budget.     

Low-frequency eddy kinetic energy spectrum in the deep Western north pacific

The frequency spectrum for the low-frequency eddy kinetic energy is estimated from a long-term current meter record obtained in a deep layer in the western North Pacific. The eddy field is characterized by three time scales: an "annual scale" with zonal dominance of eddy motions, a "temporal mesoscale" with meridional dominance, and a "monthly scale" with horizontal isotropy. About two-thirds of the eddy kinetic energy is contained in the temporal mesoscale.     

A local time-dependent sverdrup balance in the eastern north pacific ocean

Direct observations of the dynamic balance between time-dependent winds and deep ocean currents are described for the eastern North Pacific Ocean at 42 degrees N, 152 degrees W. Currents from 150 to 4000 meters below the surface at frequencies from 0.01 to 0.1 cycle per day are significantly correlated with the wind stress curl derived from U.S. Navy operational wind fields. The horizontal currents are depth-independent below 300 meters, and they flow parallel to the potential vorticity gradient derived from the earth's rotation and the large-scale bottom topography. These characteristics are expected for such periodic motions with horizontal scales larger than 500 kilometers and represent a generalized Sverdrup balance between the atmospheric forcing and the oceanic response.