used, and particularly biological ones which, being bound to certain tide 

 levels, can be reliable indicators of sea-level changes as well. Zonality is 

 particularly well shown by the varied distribution of climate -dependent 

 indicators of sea-level which in addition allows us to quantify sea-level 

 fluctuations and changes of the tidal range. (Author). 



167 KENDALL, C. St. C, and LERCHE, I. 1988. "The Rise and Fall of 

 Eustasy," Wilgus, C. K. , Hastings, B. S., Kendall, C. G., Posamentier , H. W. , 

 Ross, C. A. , and Van Wagoner, J. C. , eds . , Sea-Level Changes: An Integrated 

 Approach . Special Publication No. 42, Society of Economic Paleontologists and 



Mineralogists, Tulsa, OK, pp 3-18. 



Techniques that can be used to determine the relative magnitude of 

 eustatic excursions include the measurement of: (a) the amount of sedimentary 

 onlap onto the continental margins; (b) the thickness of marine sedimentary 

 cycles and the elevation and distance between indicators of old strandlines; 

 (c) the perturbations on individual thermo-tectonic subsidence curves and 

 stacked crustal subsidence curves; (d) the variations in deep-ocean oxygen 

 isotopes found in sediments; and (e) the size of variables, such as rates of 

 tectonic movement, sediment accumulation, and eustatic changes, used in 

 graphical and numerical simulations of basin fill that "invert" the problem. 

 To date, a combination of some or all of these methods can be used to 

 construct relative ( tectono/eustatic) sea-level curves; however, these are not 

 unique solutions to absolute eustatic variations. Each method assumes some 

 behavior for two of the three underlying processes (tectonic movement of the 

 basement, sedimentary accumulation, and eustasy), and then determines the 

 third process relative to the assumed model behavior of the other two. The 

 sense of this result is confirmed by mathematical models which suggest that 

 only the sum of tectonic basement subsidence and sea- level variations can be 

 obtained. (Authors) . 



168 KENDALL, G. St. C, and SCHLAGER, W. 1981. "Carbonates and Relative 

 Changes in Sea-Level," In: M.B. Cita and W.B.F. Ryan (Editors), Carbonate 

 Platforms of the Passive-Type Continental Margins. Present and Past . Marine 

 Geology . Vol 44, pp 181-212. 



In the geologic record some of the most accurate gages of changes in 

 sea-level are the sediment type, geometry and digenesis of carbonate shelves 

 and platforms . This is because carbonates frequently occur at or very near 

 sea-level and are usually less compacted than siliciclastics . World-wide 

 changes in relative sea- level (the sum of eustatic sea- level changes, sedimen- 

 tation and crustal movements) have occurred repeatedly and cyclicly through 

 geologic time, producing characteristic responses in carbonates. 



a. Relative rises in sea-level (usually caused by the cumulative effect 

 of tectonic subsidence and eustatic rise) may result in the following: 



(1) Drowned carbonate reefs or platforms. Here carbonate growth 

 potential is exceeded by relative sea-level ris?, and is characterized by 

 shallow-water sediments, overlain by hardgrounds and/or deep-water sediments, 

 some of which may be condensed sequences. 



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