Variation of the Earth's magnetic field strength in South America during the last two millennia: New results from historical buildings of Buenos Aires and re-evaluation of regional data

South American archaeointensity database now includes absolute intensities from 400 to 1930 AD based on 63 selected archaeointensity determinations. The data set reveals several distinct periods of quite large fluctuations of intensity. However, most data are concentrated into a relatively narrow interval from AD 1250 to AD 1450. At the beginning of the record, values between 400 AD and 830 AD match well with ARCH3k.1 model. Some general features may be detected: the time intervals from about AD 400 to 950 and 1150 to 1280 are characterized by a quite monotonic decrease of geomagnetic intensity, while some increase is observed from AD 950 to AD 1250. In contrast, a systematic intensity decay is detected from 1550 to 1930 in excellent agreement with the model prediction. No firm evidence of correlation between the climate changes over multi-decadal time scales and geomagnetic intensity was found for South America.