GEO4-1438 Paleomagnetism

Fort Hoofddijk

What is Paleomagnetism?(including geomagnetism, rock magnetism)

geophysics, (bio)geology, geochemistry

Study of system Earth

- Deep Earth (geodynamo, field behaviour)

- Lithosphere (plate tectonics)

- Earth’s surface (e.g. dating, basin

development)

- Earth & Life (e.g. climate, environment)

Paleomagnetism at Fort Hoofddijk Solid Earth (i.e. geodynamo)

We show that, on average, geomagnetic secular variation (the field variations

produced by normal geodynamo action) during the late Archaean and early

Proterozoic (2-3 Ga) was different from that of the past 200 million years.

We report new paleomagnetic data from 50 sites (1109 drilled cores) from

Marine sediments of the Cretaceous Organyà Basin in the southern Pyrenees, to

constrain the timing and magnitude of the rotation of Iberia.

Paleomagnetism at Fort Hoofddijk Shallow Earth (i.e. plate tectonics)

Here we use magnetostratigraphy and cyclostratigraphy to show that aridification,

which is indicated by the disappearance of playa lake deposits in the northeastern

Tibetan plateau, occurred precisely at the time of the Eocene–Oligocene transition.

Our findings suggest that this global transition is linked to significant aridification

and cooling in continental Asia.

Paleomagnetism at Fort Hoofddijk Earth surface (i.e. dating, climate change)

Magnetotactic bacteria produce chains of magnetite and/or greigite crystalswithin their cell bodies called magnetosomes that are permanently

magnetized.We find in Pliocene rocks from Romania greigite crystals that are consistentwith an intracellular origin.We show that these crystals are magnetosomal inorigin, which places them among the oldest greigite magnetofossils identified

so far.

Paleomagnetism at Fort HoofddijkEarth & Life (i.e. environment,

archeomagnetism)

GEO4-1438: Paleomagnetism

Teachers Mark Dekkers, Lennart de Groot, Roderic Bosboom, Wout Krijgsman (in

April)

Course Material Available on website:http://www.geo.uu.nl/~forth/(Click on: Teaching > Paleomagnetism)plus class handouts & articles

GEO4-1438: Paleomagnetism

Course structure – week 1 to 6:

Lectures (Mondays 9:00-11:00)

Geomagnetism, Statistics & models, Anisotropy & tectonics, Magnetostratigraphy, Rock magnetism, Paleointensity

Assignments (Wednesdays 9:00-11:00, odd weeks)Geomagnetism, Tectonics, Rock magnetic carriers

Discussions (Wednesdays 11:00-13:00, even weeks)Secular variation & climate, Indo-Asia collision, Paleointensity

GEO4-1438: Paleomagnetism

Course structure – week 7 to 10:

Hands-on projectCentral Anatolian crystalline complex (tectonics)Slanicul de Buzau (magnetostratigraphy)Secca Grande (tectonic rotations in a basin)

MSc Research proposalFort introductions: Monday week 7Abstract: Wednesday week 8Presentations & proposal: week 10

Grading

Assignments & Discussions30%

Hands-on project 20%MSc Research Proposal 40%Class performance 10%

N.B. There is no exam !

GEO4-1438: Paleomagnetism

GEO4-1438: Paleomagnetism

Assignments

3 assignments, 3 topics:• Geomagnetism• Tectonics• Rock magnetic carriers

Assignments and data are provided on the website

Software is (should be…) installed in the `Computerleerzalen’ and the `studielandschappen’ in BBL and Earth Sciences buildings

GEO4-1438: Paleomagnetism

Discussions

3 sessions, 3 topics:• Secular variation & climate• Indo-Asia collision• Paleointensity

4 papers per session, presented by… you (in couples)!Followed by a class discussion based on the

papers/presentations

Considered in grading:• Your presentation AND• Your participation during discussions

(also (especially!) when you are not presenting a paper in that session!)

TO DO: find a partner, scan through the papers and tell us your preference (top-3) this Wednesday!

GEO4-1438: Paleomagnetism

Hands-on project

Choose from one of the following topics:(real problems dealt with at the Fort…)

• Central Anatolian crystalline complex (tectonics)• Slanicul de Buzau (magnetostratigraphy)• Secca Grande (tectonic rotations in a basin)

Data-sets will be provided in due time

Interpret the data using your skills acquired in the first 6 weeks

Write a (scientific) report including you findings, interpretations and implications for the regional geology (with some background on the problem)

GEO4-1438: Paleomagnetism

MSc research proposal

Write your own MSc proposal, present and defend itincluding research outline, budget aspects, etc.

Two options:

Select your own topic of interestbut a paleomagnetic project is required

Select a Fort 2012 projectPossible projects (on-going studies) will be presented by

staff- dealing with planned (field) research projects - suitable for MSc research project (individual research

project)