Proposal figures: the relationship between Kappa conundrum and GOE

Question 1: If there is really a kappa (κ) conundrum?

Kappa ratio (Κ): ²³²Th/²³⁸U

Two methods of calculating κ:

·      Κ_meas=

·      Κ_Pb  =      (2)

kappa conundrum： Κ_meas ≠ Κ_Pb

·        In continental crust: Κ_meas(cc)  >  Κ_Pb(cc)

 Kappa measured: n = 69976

Mean: 4.19^+5.83_-2.10

Median 3.29

·        Kappa lead: n = 6247

Mean: 3.97^+0.27_-0.25

Median 3.91

·        In MORB: Κ_meas(MORB)  <  Κ_Pb(MORB)

Kappa measured: n = 2558

Mean: 2.98 ^+0.81_-0.64

Median: 3.04

Kappa lead: n=936

Mean: 3.84^{+ 0.09} _-0.09

Median: 3.83

Thus, the kappa conundrum does exist according to the current data.

Question 2: Does GOE caused the kappa conundrum?

    The goal here is to further constrain the mode of silicate Earth evolution using a multi-reservoir open system model incorporating material exchange among chemically homogeneous boxes (or reservoirs) with open boundaries.

    One of the key goals of this study is to find possible scenarios that can resolve the ‘‘Pb Paradoxes”, and to assess the importance of long-lived isolated reservoirs in the mantle and the effect of different continental crustal growth patterns on the isotopic evolution of the silicate Earth.

    Successful solutions reproduce the average present-day element concentrations and isotope ratios in these terrestrial reservoirs

	(Kumari et al. 2016)

 

        8 different crustal growth models will give us an idea of how the continental crust had formed through the Earth’s history.

(Kumari et al. 2016)