of Joris van Galen
Full vector geomagnetic field record,
geochemical study on 28 lava flows from El Hierro, Canary Island,
volcanic hotspot island group of the Canary Islands has resulted in
several projects at Fort Hoofddijk in recent years. Lavas from La
Palma, Tenerife, Grand Canaria and - for this project - El Hierro have
been sampled and analysed for paleomagnetic properties. During
fieldwork at El Hierro we sampled 28 lava flows and created a detailed
log of the entire stratigraphy of the section.
The objective of this project is to build a full-vector geomagnetic
field record for the period of ~150-450 Ka for the Island of El Hierro.
It will not only include the paleodirection of the magnetic north, but
a variety of techniques will be used to determine the Paleointensity of
the field during the formation of these lava flows. A high resolution
paleomagnetic record will be created providing more information on the
working of the geodynamo. This will be combined with new dating
techniques that will be conducted at the VU in August. This makes it
possible to link the intensity data to a measured age one order of
magnitude more accurate than is currently possible.
work on lavas is a fast growing research topic, which has the capacity
of answering fundamental question on the earth’s magnetic field.
Lisa Tauxe formulated these questions very well in her 2006 paper:
“What is the average value of the dipole moment? What is its
variation in times of stable polarity?
Moreover, as asked by
Rob Coe: How low has the intensity fallen without subsequent
reversal?”, and “Has there been a general trend of the
geomagnetic intensity through geologic time? Answers to these questions
require a large collection of reliable paleointensity data that span a
signiﬁcant period of time.” My results can lead to a better
understanding of the working of the geodynamo and the relation between
field strength and reversals.
on the lava flows in combination with the stratigraphic log that has
been created on El Hierro can lead to better understanding of the
evolution of the volcanic system. High resolution point measurements on
individual magnetic carriers within different samples can lead to
better understanding of the mineralogical components that play a role
in rock magnetism. The possibility of this mineralogical and chemical
approach on the samples from El Hierro can lead to new insight in the
physical aspect of magnetic carrying.
Working at sampling location
Top: View from the top of the sampling
Happy field geologist. Right: Working field geologist. All at:
Frontera, El Hierro, Canary islands, Spain.
of Joris van Galen