Short-term spectral analysis of ODP Hole 114-704B

Short-term spectral analysis was carried out on geochemical logging data from ODP Site 704. The FFT was used to compute the amplitude spectra of short-term overlapping segments to produce depth-period-amplitude spectrograms of the logging data. The spectrograms provided a means of evaluating the significance of the observed periodic components. The periodic components that were consistently present and prominent across a given record interval were considered to be significant. Changes in the spectrogram characteristics seem to reflect changes in either lithology, sedimentation rates, or hiatuses and may therefore provide useful information to aid in stratigraphic and paleoenvironmental studies. The dominant periodicity during the late Pleistocene and Brunhes Chron (0.97 to 0.47 Ma) was determined to be > 100,000 yr whereas the upper Matuyama Chron was dominated by the 41,000-yr periodicity. These periodicities suggest that the sedimentation patterns within the upper Matuyama Chron (0.98-1.78 Ma) were influenced by the Milankovitch obliquity cycle and those within the latest Matuyama-Brunhes Chron (<0.98 Ma) by the eccentricity cycle. The Brunhes/Matuyama boundary therefore represents a major discontinuity. Periodicities observed within the lower Matuyama and the upper Gauss Chron did not correlate with any of the periodicities within the Milankovitch frequency bands.

Short-term variations in radiolarian faunal dsitribution in the eastern equatorial Pacific

Two short time intervals centered at 2.3 and 4.7 Ma were studied to investigate short-term variations in surface-ocean processes as indicated by changes in the radiolarian microfossil population. These time intervals represent two different settings of late Neogene climate. The older interval represents a time when tropical circulation between the Pacific and Atlantic oceans was not blocked by the Isthmus of Panama, whereas the younger interval represents a time when Northern Hemisphere glaciation was present but did not display the dominance of the 100,000-yr cycle that characterizes the late Pleistocene. The younger time slice at 2.3 Ma was sampled at all Leg 138 sites except Site 844, where significant reworking was evident. All sites except 844, 853, and 854 were sampled for the older time slice. Samples were taken at 10- to 20-cm intervals at each site and spanned a GRAPE density maximum and minimum. Thus, it was possible to investigate whether the changes in carbonate content (as indicated by GRAPE density) were associated with changes in surface-ocean conditions (indicated by radiolarian assemblage variations). For both time slices, the radiolarian data indicate that intervals of decreased carbonate content are periods of cooler water conditions and possibly enhanced biogenic production. Times of increased carbonate content are associated with inferred warmer oceanographic conditions, as indicated by the dominance of tropical assemblages at 2.3 Ma and tropical and western Pacific assemblages during the time slice centered at 4.8 Ma. However, the spatial patterns of change during each time slice show a distinct difference in the mapped patterns of radiolarian assemblage dominance. The older time slice, representing a period before the closing of the Isthmus of Panama, shows more zonal patterns presumably associated with a more zonal character of equatorial circulation. After the closing of the isthmus, the shifts in faunal patterns between times of high and low carbonates are characterized by shifts in the dominance of the tropical and transitional assemblages, respectively, throughout the region.

Executive summaries : apprenticeship 2000 short term research projects.

Cover title.

Common stocks are short term investments.

Reproduced from typewritten copy.

Analysis of short-term variations in beach morphology (and concurrent dynamic processes) for summer and winter periods, 1971-72, Plum Island, Massachusetts /

"March 1977."

Short-term guidelines to improve crumb rubber modified asphalt concrete pavements. Final report.

Texas Department of Transportation, Austin

Oklahoma City ASAP: short term rehabilitation - analytic study no. V/VI. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Diagnosis, referral and rehabilitation within the Fairfax Alcohol Safety Action Project, 1976: the Fairfax short term rehabilitation study. Analytic study # 5/6. Volume II. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Analysis of a random-assignment short term rehabilitation program. Analytic study 5 and 6.

National Highway Traffic Safety Administration, Office of Driver and Pedestrian Programs, Washington, D.C.

Short term rehabilitation (STR) study. Interim analysis of STR performance and effectiveness. 12-month analyses. Interim report.

National Highway Traffic Safety Administration, Office of Driver and Pedestrian Programs, Washington, D.C.

Energy supply and demand in the short term, 1979 and 1980 : analysis report /

"AR/ES/79-28"

When the school board has to borrow money. Policies and procedures for short-term and long-term borrowing for public schools, with particular reference to the State of Illinois

Mimeographed.

Youthful offenders at Highfields; an evaluation of the effects of the short-term treatment of delinquent boys.

Mode of access: Internet.

Feasibility of a method for estimating short-term and long-term effects of policy decisions on the airman personnel,

"ASTIA document no. AD 217 079."