Table 1.

Major, trace and rare-earth element analyses from the Chang 7 Member oil shale

Oxide (wt%)Chang 7 Member oil shale (average, N = 54)1NASC2Trace elements (ppm)Chang 7 Member oil shale (average, N = 43)3NASC4Rare-earth elements (ppm)Chang 7 Member oil shale (average, N = 8)5Chondrite6NASC7
SiO248.6958.10Mn313.0922.0La31.00.332.0
Al2O314.4015.40Sr197.0142.0Ce56.01.073.0
TiO20.510.65Ba593.0636.0Pr6.50.17.9
Fe2O38.544.02V176.0130.0Nd24.00.733.0
MgO0.973.44Zr132.0200.0Sm4.40.25.7
CaO1.143.11Rb121.0125.0Eu0.90.11.2
Na2O0.961.30Cu98.032.4Gd3.90.35.2
K2O2.723.24Pb34.520.0Tb0.60.10.85
FeO4.003.24Zn74.570.0Dy3.60.95.8
P2O50.300.17Cr65.2125.0Ho0.80.11.0
Ni22.558.0Er2.30.33.4
Co17.126.0Tm0.40.10.5
Mo59.13.1Yb2.50.23.1
U31.93.0Lu0.40.10.48
Th6.612.3Y23.01.924.0
∑REE160.5160.5197.0

N, number of samples.

Analytical methods: the analytical method for major elements uses X-ray fluorescence (XRF) in different laboratories following Chinese standards GB/T 14506.14-2010 (AQSIQ & SAC 2010c) and GB/T 14506.28-2010 (AQSIQ & SAC 2010b); the analytical method for microelements uses XRF and inductively coupled plasma mass spectrometry (ICP-MS) following Chinese standard GB/T 14506.30-2010 (AQSIQ & SAC 2010a); and the analytical method for rare earth elements uses XRF and ICP-MS in different laboratories following Chinese standard GB/T 14506.30-2010 (AQSIQ & SAC 2010a).

  • 1 Chang 7 Member oil shale (N = 54) data were compiled from Miao et al. (2005), Changqing Oilfield Company, PetroChina (2008), Bai et al. (2009), Zhang et al. (2013), Sun et al. (2015) and Wang et al. (2016).

  • 2 NASC according to Gromet et al. (1984).

  • 3 Chang 7 Member oil shale (N = 43) data were compiled from Miao et al. (2005), Zhang et al. (2008a, b), Bai et al. (2009), Zhang et al. (2013), Sun et al. (2015) and Ma et al. (2016).

  • 4 NASC according to Gromet et al. (1984).

  • 5 Chang 7 Member oil shale (N = 8) data were compiled from Bai et al. (2009) and Ma et al. (2016).

  • 6 Chondrite according to Taylor & Melennan (1985).

  • 7 NASC according to Gromet et al. (1984).