Although the exact species is not known at present, it may be the Mexican vole which is found today at high elevations in the Sacramento Mountains of New Mexico and in the Guadalupe Mountains of Texas. The environment must have been sufficiently different at that time to have met the ecological requirements of Colorado pinyon.Īlso recovered from our oldest midden were teeth of a vole. Several lines of evidence lead to the conclusion that the climate in this portion of the Southwest and northern Mexico was cooler, and there was probably greater rainfall and lower evaporation rates. The questions then arise as to which factors, present several thousand years ago but not present today, provided a favorable environment in the Hueco Tanks region for Colorado pinyon pine. The conclusion a paleoecologist makes, based solely on this information, is that 12,000 to 14,000 years ago this pinyon was more widespread. Other midden records from greater than 34,000 to about 11,000 years ago in Trans-Pecos Texas also reveal the presence of Colorado pinyon. Today this pine is widely scattered throughout the Southwest and is known in Texas from higher elevations in the Guadalupe Mountains, the Sierra Diablo, and the Delaware Mountains. The most significant extralocal species (not occurring at the site today) was Colorado pinyon. Perhaps two middens are modern.Īnalysis of the oldest midden at Hueco Tanks revealed the presence of 29 different species of plants, 5 of which do not grow in the park today. A younger midden was dated to about 9,380 years ago, while several other undated middens are estimated to date from as long ago as 11,000 years to as recently as 800 to 900 years ago. Radiocarbon analysis of the oldest one yielded a date of approximately 13,500 years before the present. Portions of at least six pack rat middens from Hueco Tanks have been analyzed. Such information is used to interpret the significance of ancient plant remains preserved in the middens. At Hueco Tanks a survey was conducted of the plant communities now occurring in the park, and a detailed modern species list was developed (see Natural Settingfor examples). The basis for any pack rat midden analysis is an understanding of the contemporary flora and fauna of a site. These studies help to reconstruct ancient environments and climates. These include studies of cave deposits, archeological sites containing vertebrate remains, and pollen analysis of ancient sediments. This history is further elucidated when compared to the regional vegetation history developed through many methods of paleoecological analysis. ![]() The plant fossils preserved in middens from Hueco Tanks contain a history of the park's vegetation during the past 14,000 years. The paleoclimatic sequence of the Hueco Bolson, and Hueco Tanks in particular, has been approximated through pack rat midden analyses. Thorny scrub, including low cacti, sotol, and mesquite, grow among grasses at Hueco Tanks.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |