The ritualistic practice of burn down huts and grain bin in South African agricultural biotic community might give scientist some clues as to the process that run to the blow of the planet ’s magnetic theatre of operations . The special placement of the army hut is important , because they sit in a part that has long been fuck to be a weak spot in the Earth ’s magnetic field . By analyzing a special mineral formed by the combustion of the shanty , the researcherswere able to tag how the magnetic field in this area has change over time .
The resultssuggest that underneath these huts , the Earth ’s core might play an important role in the reverse of the planet ’s magnetic pole . The last time the poles switched is thought to have been around 800,000 years ago , and some suggest that this process , which can take 15,000 years to complete , has start again . Equally , the magnetic force field of the major planet is known to vary so we could just be see instinctive fluctuations . But how the reversal actually happen has remained a bit of a mystery .
“ It has long been thought about-face start at random locations , but our study suggests this may not be the case,”explainsJohn Tarduno of theUniversity of Rochester . The investigator looked at data from five web site in South Africa , which sit in a region known as the South Atlantic Anomaly , a plot of the Earth ’s magnetic orbit that is bizarrely weak . They suggest that deep below this patch , a particular area of the mantle rock-and-roll overlaying the planet ’s centre influence how the liquid smoothing iron inwardness of the Earth flows , which in turn causes the geometrical irregularity in the Earth ’s charismatic field .
Magnetic theatre of operations enduringness in the South Atlantic Anomaly . cite : Michael Osadciw / University of Rochester
“ The top of the nitty-gritty beneath this region is overlain by unusually spicy and dense Mickey Charles Mantle rock,”saysTarduno . That mantle rock lies 3,000 kilometers ( 1,864 international nautical mile ) below the surface , and is or so 6,000 kilometers ( 3,728 miles ) across .
They find that the priming coat moderate the ash and remain of the shanty that were burnt down a thousand geezerhood ago turn back the mineral " magnetite . " When this mineral is subjugate tohigh temperatures , such as at the time of the burning , it is “ re - write ” with a “ new record of the magnetic field intensity level and direction ” from that region at that time .
The study , published inNature Communications , find that between 1225 and 1550 CE , there was a sharp 30 % drop in magnetic chroma in the region . With the Earth ’s charismatic field speciality having dropped by 16 % since 1840 , some mass think that it could indicate the beginning of another cps in which the planet ’s Pole interchange , though the researcher of this study think it could simply be a feature of a larger wheel of magnetic shifts .
“ Because rock in the deep Mickey Mantle moves less than a centimetre a twelvemonth , we know the LLSVP is ancient , meaning it may be a longstanding land site for the departure of magnetic field strength,”saidTarduno . “ And it is also potential that the region may actually be a initiation for magnetic rod reversals , which might happen if the decrepit field region becomes very large . ”
