bedrock u-th-k signatures in the ongoing european …bedrock u-th-k signatures in the ongoing...

Bedrock U-Th-K signatures in

the ongoing European Atlas of

Natural Radiation Roberto Braga

BiGeA, Università di Bologna, Italy

Giorgia Cinelli Tore Tollefsen Marc de Cort

European Commission, Joint Research Centre (JRC), Institute for Transuranium

Elements (ITU), Nuclear Security Unit, Ispra (VA), Italy

European Atlas of Natural Radiation

MAPS STATUS NOTES

Indoor Radon - EIRM advanced 26 countries!!

Geogenic Radon - EGRM first version Improvements:

Multivariate approach

Cosmic radiation first version

Terrestrial gamma dose rate - TGDR in progress Estimation from

EURDEP data

U, Th and K in soil and bedrock in progress

Outdoor radon in discussion phase

Water (ground and surface water) in discussion phase

Total dose by natural radiation in discussion phase Extensive modelling &

additional spatial

demographic data needed

THE REAL BEDROCK

30 cm

Matteo Verocai, BSc 2011

TOOLBOX

• Geological maps. Where the bedrock units

are (GU, Geological Units)

– OneGeology

• Whole-rock U-Th-K data to assign to GUs

– EarthChem

Cinelli et al. 2015

BEDROCK LITHOLOGY

BEDROCK LITHOLOGY

> 60 GUs

• It’s a IEDA

Interdisciplinary Earth

Data Alliance initiative

• Community-based, on

voluntary basis

• Data to be discovered

and reused by a diverse

community now and in

the future.

EarthChem

EarthChem

> 55 000 samples for Europe (> 850k World)

AUSTRIA_EarthChem

• 111 data

• 33 with U

• 5 locations

• > 1100 data

• Igneous rock

bias

SPAIN_EarthChem

OneGeology & EarthChem

A DISMAL PERFORMANCE ?

• OneGeology

– Too many GUs

• EarthChem

– Lots of data but clustered

– Sedimentary rocks (limestone, sandstone…)

are underrepresented

A MODIFIED APPROACH

• Starting point: national geological maps

(1:1M or 1:2M)

• Discard

– Quaternary (not solid rock)

– Ultramafics (not enough U Th K; Braga & Cinelli,

Ofioliti 2014)

• GUs by lithostratigraphy

https://www.geologie.ac.at/

23 GUs

(1:2M)

AUSTRIA

• Lithostratigraphy

• ≈ 20 GUs

• Maintain bedrock

complexity

• Merge the 1G

units into ≈ 20

GUs

• Chronostratigraphy

• > 40 GUs

• in 1G ≈ 140

• Group by similar

lithology

SPAIN

U-Th-K DATA

• Igneous + metamorphic rocks

– EarthChem + geoscience literature

• Sedimentary rocks

– Literature; not many data

• Processed ≈ 3000 data (Austria)

• U-Th-K averages for each GU

BEDROCK MAP vs. TGDR

Bossew et al.,2015

Based on Visual Analysis

Natural gamma radiation map of

Spain. Quindós et al. (2004).

Based on Visual Analysis

Umhausen

Uranium MAP vs. RnRiskMap

• Radon Risk Map

(indoor Rn)

Courtesy of Valeria Gruber

CONCLUSIONS

• A (imperfect) method for U-Th-K bedrock

maps

• Gamma Rad maps and indoor Rn

preserve bedrock signature

• U-Th-K for Sed Rocks – a problem

• Literature check = time consuming

Roberto Braga Scienze Biologiche Geologiche e Ambientali (BiGeA)

r.braga@unibo.it

www.unibo.it

T. Plank

The Chemical Composition of Subducting Sediments

http://dx.doi.org/10.1016/B978-0-08-095975-7.00319-3

U-Th-K SED ROCK

• An open question

• Today’s sediments

U-Th-K signature ≈

sedimentary rock

• In similar

depositional

environment