GIGJ - GOCE Inversion for Geoneutrinos at JUNO

This web page provides the numerical 3D crustal model constituted by 50 × 50 × 0.1 km voxels, built by inverting gravimetric data over the 6° × 4° area centered at the Jiangmen Underground Neutrino Observatory (JUNO) experiment and published in:

Reguzzoni, M., L. Rossi, M. Baldoncini, I. Callegari, P. Poli, D. Sampietro, V. Strati, F. Mantovani, et al. - GIGJ: a crustal gravity model of the Guangdong Province for predicting the geoneutrino signal at the JUNO experiment. Journal of Geophysical Research: Solid Earth, 124(4), 4231-4249 (2019). DOI 10.1029/2018JB016681

  Mirko Reguzzoni (Corresponding author)

GOCE

 

GOCE (Gravity field and steady-state Ocean Circulation Explorer) was an ESA mission, aiming at modelling the Earth gravitational potential by directly observing its second order derivatives in space. Using GOCE, gravity anomalies are globally retrieved with an accuracy of 1 mGal at a resolution of about 80-100 km.

Geoneutrinos

Geoneutrinos are electron antineutrinos emitted by the progenies of U and Th decays in the Earth. With a flux of some 106 cm-2 s-1, geoneutrinos bring to the surface real time information coming from the whole planet as they can escape freely and instantaneously from the Earth’s interior, providing insights on the Earth’s composition and radiogenic heat budget.

JUNO

* from JUNO collaboration

JUNO (Jiangmen Underground Neutrino Observatory) is a 20 kton multipurpose underground liquid scintillation detector having as primary Physics goal the determination of the neutrino mass hierarchy from the observation of reactor antineutrinos. JUNO will also observe geoneutrinos with a rate of ∼ 400 events per year, significantly improving the statistics of existing geoneutrino measurements.

Where do geoneutrinos measured at JUNO come from?

The geoneutrino signal that will be detected by the JUNO detector is produced by:

• Bulk Crust for the ~73%

• Continental Litospheric Mantle (CLM) for the ~5%

• Mantle for the ~22%

Half of the crustal signal comes from the area within 500 km radial distance from the detector (Strati et al., Expected geoneutrino signal at JUNO, Progress in Earth and Planetary Science, 2015)

Geological sketch of the GIGJ study area

The 6° × 4° study area (green rectangles) includes the northern margin of the South China Sea (SCS), the Guangdong region and the south-eastern part of Guangxi region. From the tectonic point of view, the study area is part of the Cathaysia Block, a collided Neoproterozoic continental crustal block divided in the Cathaysia Interior (CI), the Cathaysia Fold Belt (CFB) and the South-east Coast Magmatic Belt (SCMB) on the basis of two regional geological features, the Shi-Hang Zone (SHZ) and the Lishui-Haifeng Fault (LHF).

The vertical crustal layers distribution (Upper Crust - UC, Middle Crust - MC and Lower Crust - LC) exhibits a lateral variation moving to the Transition Zone (TZ) towards the oceanic crust. A Sinian-Mesozoic sedimentary cover (parallel black lines) is present together with Triassic (grey triangles), Jurassic (black triangles) and Cretaceous (red triangles) intrusions.

Depth maps of the crustal layers surface boundaries

GIGJ is a model assuming a layered crust and a single-layer Uppermost Mantle (UM). The following discontinuity surfaces are defined: the topography/bathymetry, the bottom of SEDdiments (i.e. the Top of the Upper Crust (TUC)), the Top of the Middle Crust (TMC), the Top of the Lower Crust (TLC), the Moho Discontinuity (MD) and a horizon with a constant depth of 50 km, which is the bottom of the model.

 

 

 

The model can be downloaded at this link.