El paleoclima de la América preincaica. Interpretación palinológica
Abstract
El presente trabajo es un ejemplo de cómo los resultados del método palinológico pueden complementarse con los de otras ramas de la ciencia. Se intenta determinar la forma en que el hombre prehispánico se ha adaptado a los cambios del clima y a la vegetación postglacial, y también como él ha modificado el medio ambiente. Para ello se estudian cinco perfiles polínicos generalizados que se sitúan entre la puna de Atacama y la República del Ecuador. En los diagramas se encuentra gran predominio de gramíneas y menor representación del aliso en los desiertos del sur. Por otra parte, el análisis polínico atestigua la presencia de pocas plantas cultivadas, ya que la ausencia de polen característico es notoria; a este respecto, son excepciones remarcables el maíz, el algodón, los frijoles, y quizás la tuna, la quinua y la papa. En la investigación de la época prehispánica se hace necesario desestimar la presencia de plantas de cultivo que fueron introducidas con posterioridad, por ejemplo el arroz, la caña de azúcar y los demás cereales, así como el café, el plátano (banano), la manzana, el durazno y las frutas cítricas. Este hecho indica que las modificaciones introducidas por el hombre han sido muy marcadas; por el contrario, la migración de la vegetación natural ha sido muy restringida durante el Holoceno. El cambio climático se ha desarrollado de forma diferente en las distintas regiones. Si se compara con el presente, en la costa chilena septentrional y en el Perú se tenía un clima más seco en el Holoceno medio, pero más húmedo en el Holoceno superior. En las cordilleras y en el Altiplano se impuso un clima en el que las precipitaciones fueron aumentando paulatinamente durante todo el Holoceno, desde condiciones secas, hace 10.000 años, hasta el clima semiárido o semihúmedo actual. La ocupación humana prehistórica de los Andes durante el Holoceno inferior y medio está probada por el descubrimiento de muchos sitios arqueológicos. Asimismo, se tienen indicios de ocupaciones similares en el litoral ecuatoriano. La ocupación de oasis fluviales en la costa peruana parece ser más tardía, pudiendo haberse dado sobre todo en el Holoceno superior, aunque empezó a fines del Pleistoceno y era acentuada durante el precerámico medio. Se intensificó entonces más o menos sincrónicamente con las culturas de Chavín, de Tiahuanacu y de Huari, cuyos núcleos se situaban en la sierra. Al parecer, las migraciones en forma organizada desde el litoral hacia el cordón cordillerano y hacia el oriente empezaron durante esta época. Se pueden aducir factores climáticos en las adaptaciones humanas, un fenómeno de El Niño más intenso que pudo haber disminuido, en algunos sectores, las posibilidades de pesca Pudieron haber incrementado los peligros de inundación, aumentando el desarrollo de pantanos, y con ellos la presencia de enfermedades conexas. Por otra parte, la desecación de lagos y fuentes de agua pudo deberse al clima seco del Altiplano sur; en este sector, la desertificación pudo haberse iniciado en el Holoceno medio.
The article is an example of how palynological data can be complemented with results obtained by other scientific disciplines. The author's goal is to determine how prehispanic populations have adapted to climatic changes and postglacial vegetation and how they changes their environment. With this purpose, five palynologic profiles are studied, situated between the Atacama puna and the Republic of Ecuador. Diagrams show a marked prevalence of Graminea and lesser representation of (alder) in the southern deserts. On the other hand, pollen analysis shows the presence of few cultivated plants by the absence of characteristic pollen; exceptions are maize, cotton, beans and maybe (prickly pear), quinoa and potatoes. As we investigate prehispanic periods we have to discard the presence of cultivated plants that were introduced only later, such as rice, wheat and other cereals, and also coffee, bananas, apples, peaches and citrus fruits. The fact indicares that modifications introduced by men were well marked; on the contrary, little natural vegetation migrations occurred during the Holocene. Climatic changes ocurred in different way s according to different regions. If we compare past with present conditions the northem chilean coast and Perú had a dryer climate during the Middle Holocene, and a more humid one during the Late Holocene. The Cordilleras and Altiplano showed a climate with increasing rainfall during the Holocene, from dry conditíons 10,000 years ago to the present semi arid or semi humid climate. Prehistoric human occupation of the Andes during the Inferior and Middle Holocene has been proved by the findings of many archeological sites. There are also indications of similar occupation of the ecuatorian coast. The settlements of fluvial oasis of the perú vian coast seam to be posterior, having occured mostly during the late Holocene, even if they started at the end of the Pleistocene and intensified during the middle preceramic period. Human occupation developed almost simultaneously with the Chawin, Tiahuanacu and Huari cultures, which were based in the sierras. Apparently, organized migratíons from the coast towards the Cordilleras and the east iniciated during this period. Climatic factors can be involved for these human adaptatíons, such as a more intense El Niño phenomenon, which could have disminished fishing opportunitíes in some sectors. Inundatíon risks also increased, causing larger bogs, and with them the prevalence of illnesses. On the other side, the drying of lakes and water sources could have been caused by the dryer climate of the Southern altiplano. In this areas, desertification could have already started durring the Middle Holocene.
The article is an example of how palynological data can be complemented with results obtained by other scientific disciplines. The author's goal is to determine how prehispanic populations have adapted to climatic changes and postglacial vegetation and how they changes their environment. With this purpose, five palynologic profiles are studied, situated between the Atacama puna and the Republic of Ecuador. Diagrams show a marked prevalence of Graminea and lesser representation of (alder) in the southern deserts. On the other hand, pollen analysis shows the presence of few cultivated plants by the absence of characteristic pollen; exceptions are maize, cotton, beans and maybe (prickly pear), quinoa and potatoes. As we investigate prehispanic periods we have to discard the presence of cultivated plants that were introduced only later, such as rice, wheat and other cereals, and also coffee, bananas, apples, peaches and citrus fruits. The fact indicares that modifications introduced by men were well marked; on the contrary, little natural vegetation migrations occurred during the Holocene. Climatic changes ocurred in different way s according to different regions. If we compare past with present conditions the northem chilean coast and Perú had a dryer climate during the Middle Holocene, and a more humid one during the Late Holocene. The Cordilleras and Altiplano showed a climate with increasing rainfall during the Holocene, from dry conditíons 10,000 years ago to the present semi arid or semi humid climate. Prehistoric human occupation of the Andes during the Inferior and Middle Holocene has been proved by the findings of many archeological sites. There are also indications of similar occupation of the ecuatorian coast. The settlements of fluvial oasis of the perú vian coast seam to be posterior, having occured mostly during the late Holocene, even if they started at the end of the Pleistocene and intensified during the middle preceramic period. Human occupation developed almost simultaneously with the Chawin, Tiahuanacu and Huari cultures, which were based in the sierras. Apparently, organized migratíons from the coast towards the Cordilleras and the east iniciated during this period. Climatic factors can be involved for these human adaptatíons, such as a more intense El Niño phenomenon, which could have disminished fishing opportunitíes in some sectors. Inundatíon risks also increased, causing larger bogs, and with them the prevalence of illnesses. On the other side, the drying of lakes and water sources could have been caused by the dryer climate of the Southern altiplano. In this areas, desertification could have already started durring the Middle Holocene.
Description
No. 27