The Ten Thousand Islands (TTI) are a myeariad of low- relief mangrove 

 islands that lie along the low energy, subtropical southwest Florida coast. 

 The region has been subjected to a relative rise in Holocene sea- level, which 

 has continuously decelerated to its present rate. 



Data derived from surface and subsurface sampling indicate that the 

 Holocene sediment package of the TTI area consists of two sediment sequences. 

 The lower sequences consists primarily of 1) biogenic shallowing upwards 

 sequences or 2) thickened mangrove peat layers, reflecting island emergence 

 and shoreline stabilization, respectively. Island emergence compartmentalized 

 the area, further reducing wave and current energy and promoting the infilling 

 of the protected bays through deposition of organic-rich shelly mudstone and 

 wackestone. Based on coastal stratigraphy and '""C dates, the formation of 

 this transgressive/regressive sediment sequence is directly related to 

 changing rates of Holocene sea- level rise, reported to have occurred between 

 3,500 and 3,200 YBP. 



Continued regressive sedimentation could eventually generate a 5-10 m 

 thick transgressive/regressive sediment couplet, with an aerial extent of over 

 300 km^, in roughly 10,000 years. This externally forced sediment couplet 

 compares remarkably well to individual small scale transgressive/regressive 

 cycles which repeat tens to hundreds of times throughout the geologic record 

 (see James 1984) . The results of this study thus support the allocyclic 

 mechanism as a viable working hypothesis for the generation of these small 

 scale rock cycles. (Author). 



261 PATTULLO, J., MUNK, W. . REVELLE , R. , and STRONG, E. 1955. "The 

 Seasonal Oscillation in Sea-Level," Journal of Marine Research . Vol 14, 

 pp 88-155. 



On the basis of all available tide gage records, bathythermograms , and 

 Hansen bottle casts, we have compiled, on a global scale, monthly departures 

 of recorded and steric sea- levels from their annual means. The steric fluct- 

 uation is defined in terms of the seasonal fluctuation in specific volume. 

 The results are given in the appendices and in three charts, together with 

 error estimates. In general, the departures are comfortably above the uncer- 

 tainties introduced by year to year variations and by the effects of local 

 topography. 



Recorded and steric departures agree remarkably well in low and temper- 

 ate latitudes (conditions are isostatic) . In these regions the steric levels 

 are associated largely with temperature fluctuations in the upper 100 m. In 

 high latitudes conditions are indeterminate. 



Pronounced semiannual fluctuations are found along the west coast of 

 South Africa, in Indonesia, in corresponding regions of the Labrador and 

 Oyashio currents, and in the Gulf of Mexico and adjoining Gulf Stream stations 

 (but not in the Kuroshio!). Elsewhere the oscillations are largely annual in 

 character, with low sea- level in each hemisphere during its spring and with 

 high level during the fall. Recorded amplitudes vary from a few centimeters 

 in the tropics to a few decimeters at higher latitudes; they exceed one m in 

 the Bay of Bengal. Atmospheric pressure effects and long period astronomic 

 tides account for only a small part of the recorded fluctuations. (Authors). 



118 



