Archeomagnetic and paleomagnetic dating
The younger one was emitted in 1870 and used to validate the method, while the older one known as Ceboruco flow is of unknown age but probably younger than ∼1005 AD and older than 1528 AD.
Each flow was sampled in at least four sites, in order to unravel between site variations.
The Earth's magnetic core is generally inclined at an 11 degree angle from the Earth's axis of rotation.This is also true for Ceboruco lava flow, and overall mean directions and palaeointensities were then used for palaeomagnetic dating applying the Matlab tool and the global palaeosecular variation model SHA. For the 1870 lava flow, the dating resulted in an age ranging between 17 AD (95 per cent probability level), which includes the real emplacement age.In addition, the Ceboruco lava flow was dated between 10 AD, which is close to the large plinian Jala eruption producing the crater of Ceboruco volcano around 1005 AD.The direction and magnitude of the magnetic field of the Earth at a particular location varies with time, and can be used to constrain the age of materials.In conjunction with techniques such as radiometric dating, the technique can be used to construct and calibrate the geomagnetic polarity time scale.
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Definition: Archaeomagnetic dating is a method of assigning a date to a fireplace or burned earth area using the earth's magnetic field.