Torres Pérez-Hidalgo, Trinidad José
The palaeoenvironmental and palaeohydrological evolution of
Padul Peat Bog (Granada, Spain) over one million years, from
elemental, isotopic and molecular organic geochemical proxies.
"Organic geochemistry", v. 35
The elemental (concentration of organic carbon, atomic H/C and C/N ratios), isotopic (<513C values of organic matter)
and molecular (predominant w-alkane chain length and carbon preference index (CPI)) organic components were
measured for 600 samples taken from a 107-m long core from the Padul Basin (Andalusia, Spain). The record runs from
the Lower Pleistocene (ca. 1 Ma B.P.) to the mid-Holocene (ca. 4.5 ka B.P.) with, in general, little diagenesis (removal of
components). Two markedly different hydrogeological scenarios were interpreted: (1) From ca. 1 Ma to ca. 400 ka B.P.
run-off recharge was significant and water depths were greater (lacustrine scenario). From ca. 400 to 4.5 ka B.P., the
Padul Basin became a peat bog s.s. with the major water input coming from groundwater inflow. From ca. 400 to
ca. 180 ka B.P. alternating episodes with either predominant grasses, trees or aquatic macrophytes which were linked
to wet/dry phases, took place. An important deglaciation episode has been interpreted to occur between ca. 180 and 170
ka B.P. The global climatic changes occurring from ca. 170 to 25 ka B.P. were not recorded in the proxies, though they
do show important variations linked to the Last Glacial Maximum and the beginning of the Holocene (ca. 25-10 ka
B.P.): (2) Cold phases coexisting with dry periods produced the recession of forests and the development of grasses.
After these periods, as both temperature and precipitation increased, forests expanded and the water level, linked to
thaw, rose, especially at ca. 20 ka B.P. Few changes occurred during the Holocene, although there were short alternations
between wet and dry episodes. Overall, the techniques applied proved to be excellent palaeoenvironmental proxies
for studvina the basin's palaeoclimatological and palaeohydrological evolution.