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Holocene

Note: The content of kaolinite in the Quaternary sediments deposited in the cave levels was obtained by multiple regression of absorption in the infrared spectrum.

K (%) = 7.7882 A3 /A4 + 46.7491 A5 /A6 - 25.7192, where A3 = A (925 cm"1), A4 = A (808 ± 3 cm"1), A5 = A (1040 cm-1), A6 = A (1117 ± 3 cm-1)

Holocene

Note: The content of kaolinite in the Quaternary sediments deposited in the cave levels was obtained by multiple regression of absorption in the infrared spectrum.

K (%) = 7.7882 A3 /A4 + 46.7491 A5 /A6 - 25.7192, where A3 = A (925 cm"1), A4 = A (808 ± 3 cm"1), A5 = A (1040 cm-1), A6 = A (1117 ± 3 cm-1)

and kaolinite (Fagundo et al., 1984a,b). The highest caves are the oldest (Acevedo, 1971) and are related to ancient base levels of paleovalleys of erosive and erosive-denudative karstic origin. These caves formed as a consequence of variations in sea level and the associated adjustments of the equilibrium profiles of rivers and streams. Lower sea levels produced hanging caverns representing relicts of earlier processes. Each cave level reflects one level of erosion (Acevedo, 1970). The ages of the cave levels were estimated based on the geomor-phologic evolution of the region (Acevedo, 1970, 1971).

The parameter kaolinite to quartz (K/Q) has been used to estimate the degree of evolution of Quaternary sediments. The increase in the percentage of kaolinite and the K/Q ratio in the upper cave levels suggest periods of increased humidity or, more likely, long exposure times. Hydrological behavior, which can be derived by analysis of granulometric characteristics as they relate to the mechanism of selective transport, must also be considered.

According to our research in karst areas (representing 77% of the Cuban surface), the late Pleistocene and Holocene seem to have been marked by transport and deposition of large pebbles and also by a well-defined distribution of scallops on the walls, ceilings, and floors of the underground passages, indicating erosive and corrosive processes.

13.2.1. Paleoclimatic Indices

To obtain a quantitative assessment of the paleo-rainfall and paleoflow in the study area, we analyzed different morphological parameters in the cave systems.

To measure the geometrical parameters on scalloped surfaces in cave passages (length, width, depth, and alpha and beta angles), a SCALLOGRAPHER EPC-01 device was constructed and used in the measurement of thousands of scallops in underground passages.

Random sampling of the fluvial load in representative underground passages was used to determine the length, width, depth, and weight of several generations of pebbles. A detailed description of the studied sites (system, subsystem, sector, place, and point), including geographical coordinates, was made, and topographic maps (surface and profile) of the points of scallop measurement were drawn to estimate the area and perimeter of the transversal section in the gallery.

This information was included in the Quaternary Paleoenvironmental Data Base (see Appendix).

The graphical method of statistical symmetry analysis of scallops proposed by Lauritzen (1981), based on the inflection point angles of scallops (alpha and beta angles), was used to determine the paleohydrological behavior of the main transects in the underground galleries (Fig. 3).

By testing a normal distribution for all the measured scallop formations in the system (number of measurements generally ^30), the paleoflow and direction of the water flow were determined.

A brief description of the transects (Fig. 3).

• Transect No. 1: The data show a clear paleoflow direction from the basin of the Majaguas stream in the contact valley between the Alturas de Pizarras del Sur

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