Fossil Coral, Spirits in the Sand, and Lakes in the Sahara

6 Mar 2010

Science Daily March 2nd id100301182106 ... fossil coral a half a million years of age seems to show reefs are quite capable of withstanding stress imposed by global warming - or freezing. Reef ecosystems appear to have persisted through massive environmental changes imposed by sharply falling sea levels during previous Ice Ages. Eight reefs on Papua New Guinea show they survived from Ice Age to Ice Age (and the warming between). It is assumed sea levels fell, rose, and fell once again as ice built up in northern latitudes.

National Geographic March 3rd ( ) 'Spirits in the Sand' is an article on the Nasca Lines and is probably somewhat out of date. In spite of this it is a good article on the enigmatic symbols left behind in the desert in the shape of animals such as Orca (killer whale), Hummingbird, and Monkey, Spider etc. Maria Reiche thought they represented an astronomical calendar - others saw them as Inca roads, images to be appreciated from hot air balloons, or landing strips for alien spacecraft. Since 1997 a joint Peruvian-German research team has mounted a systematic study of the people of the region - how they lived, why they disappeared, the meaning of the strange designs. The story, it is now thought, begins and ends in water. The coastal zone of southern Peru and northern Chile is extremely arid. Water is highly valued and in the small basin where the Nasca culture flourished ten rivers descend from the Andes foothills - most of them dry  for part of the year. The ten streams offered a fertile hotspot for the emergence of early civilisation - a perfect place for humans simply because it possessed water. However, the macro-climate in the Nasca basin has oscillated dramatically over the last 5000 years - but whenever the water has flowed people have gravitated there. The amount of water in the Andes rivers has a direct connection with rainfall patterns over the mountains - movements in the monsoon track can bring drought. It is significant that what is known as the Nasca culture arose in 200BC, following a glitch in climate (and rainfall). It succeeded what is known as the Paracas culture and like them, people cultivated cotton, beans, tubers, lacuma and corn. They had a distinctive pottery - made by mixing mineral pigments in a thin wash of clay so that the colours were baked into the ceramic. The ceremonial centre of Cuhuachi in which people from the hills and all around brought offerings - including severed heads with a braided rope strung through a hole drilled in the forehead. By simply removing a layer of dark stones cluttering the desert and exposing lighter sand beneath the Nasca created their famous markings - which have endured for centuries. However, the earlier Paracas culture also created geoglyphs - such as human figures with buggy eyes and bizzare rays of hair. These were placed on hillsides where they could be seen from the pampa below. Later, in the Nasca period, they migrated from the hills into the desert and became pathways for ceremonial processions. The geoglyphs became a route to be walked upon - rather than to be seen. It was communion with the deities they represented - or that is the general interpretation. Basically, it was all about water rituals - in response to drought (including ritual sacrifice). In the 6th century AD the aridity got worse and people moved further into the hills and high valleys but by 650AD the Wari Empire from the central highland zone supplanted the Nasca ruling class. March 2nd ... Lakes of the Sahara Desert seen from the International Space Station. Apparently, around ten lakes exist in the middle of the Sahara, in the Ounianga Basin in NE Chad, a remnant of what was once a single large lake 10s of km long that occupied the region between the end of the Ice Age (15,000 years ago) and approximately 5500 years ago. Since the lake has been reduced in size and invaded by wind driven sand dunes which divided it into several small strips of water, other factors have threatened it's future - not least the blazing hot sun and high evaporation rates. Yet the water remains fresh - not in any way brackish. This is because they are fed by an aquifer which reaches the surface in the Ounianga Basin - which is in effect a Depression in the geology. The aquifer is large enought to supply the lakes with water in spite of the merciless temperatures. The water is part of a hydrological system, a throwback to the Early Holocene era when the desert was savannah with numerous herds of animals and thriving human cultures.