Diagenesis and very low grade metamorphism in a 7,012 m-deep well Hongcan 1, eastern Tibetan plateau

Wang, Hejing; Ma, Yongsheng; Zhou, Jian; Xu, Tingjing

doi:10.1007/s00015-012-0105-5

Swiss Journal of Geosciences

Table 1 EMPA data of chlorite, muscovite, illite and calcite measured from rock’s matrix and b cell data of K-white mica of part core samples and their depths

From: Diagenesis and very low grade metamorphism in a 7,012 m-deep well Hongcan 1, eastern Tibetan plateau

No	HW- 591-3	HW- 698-3	HW- 699-4	HW- 699-5	HW- 733-2	HW- 733-5	HW- 733-6	HW- 734-1	HW- 589-2	HW- 698-7	HW- 699-8	HW- 732-4	HW- 733-4	HW- 734-6	HW- 589-3	HW- 591-1	HW- 698-1
Depth (m)	4945.2	5847.5	6006		6543.7			7011.2	4375.1	5847.5	6006	6073.2	6543.7	7011.2	4375.1	4945.2	5847.5
Phase	Chlorite								Illite	Muscovite					Calcite
SiO₂	26.33	25.83	24.86	24.93	24.5	24.78	24.88	24.40	52.41	45.92	46.77	48.12	46.56	45.6	0.14	0.05	0.07
TiO₂	0.02	0.05	0.05	0.09	0.12	b.d.	0.08	0.10	0.43	0.35	0.19	0.30	0.44	0.24	0.04	b.d.	b.d.
Al₂O₃	21.49	23.78	21.57	21.35	21.24	21.67	21.99	24.27	30.22	33.7	34.33	33.05	32.33	35.90	0.02	0.03	0.07
Cr₂O₃	b.d.	0.12	0.07	0.04	0.02	b.d.	0.08	0.02	b.d.	b.d.	0.04	0.09	0.34	0.02	b.d.	b.d.	b.d.
FeO	25.24	26.59	29.16	29.19	27.43	27.84	27.28	30.64	2.47	1.63	1.26	1.76	1.99	1.00	1.02	1.00	1.39
NiO	0.06	0.03	0.03	0.04	0.05	b.d.	0.02	b.d.	b.d.	0.02	b.d.	b.d.	b.d.	b.d.	0.02	b.d.	b.d.
MnO	0.05	0.07	0.06	0.04	0.03	0.13	0.05	b.d.	b.d.	b.d.	b.d.	b.d.	b.d.	0.03	1.73	0.22	0.18
MgO	13.37	12.76	11.39	11.91	13.37	12.83	13.55	8.91	1.69	1.25	0.82	1.24	1.48	0.32	0.36	0.57	0.46
CaO	0.27	0.08	0.13	0.15	0.11	0.04	b.d.	0.18	0.04	0.03	0.06	0.05	b.d.	b.d.	52.11	54.12	52.55
Na₂O	b.d.	0.03	b.d.	b.d.	0.03	b.d.	b.d.	b.d.	0.14	0.30	0.65	0.32	0.26	1.22	b.d.	b.d.	b.d.
K₂O	0.17	0.43	0.02	0.04	b.d.	b.d.	0.02	0.22	9.13	10.64	10.29	10.23	10.66	9.80	b.d.	0.04	0.02
Total	86.99	89.76	87.33	87.78	86.89	87.32	87.95	88.76	96.53	93.86	94.4	95.17	94.07	94.13	55.45	56.04	54.75
Based on	28 O								11 O						1 O
Si	5.576	5.332	5.371	5.361	5.284	5.319	5.280	5.210	3.387	3.103	3.128	3.189	3.145	3.056	0.002	0.001	0.001
Ti	0.003	0.008	0.008	0.015	0.019		0.013	0.016	0.021	0.018	0.010	0.015	0.022	0.012	0.001
Al	5.364	5.785	5.492	5.411	5.398	5.482	5.500	6.107	2.302	2.684	2.706	2.582	2.574	2.836	0.000	0.001	0.001
Cr		0.020	0.012	0.007	0.003		0.013	0.003			0.002	0.005	0.018	0.001
Fe*	4.470	4.590	5.268	5.249	4.947	4.997	4.842	5.471	0.120	0.083	0.063	0.088	0.101	0.050	0.014	0.014	0.020
Ni	0.010	0.005	0.005	0.007	0.009		0.003			0.001					0.000
Mn	0.009	0.012	0.011	0.007	0.005	0.024	0.009							0.002	0.025	0.003	0.003
Mg	4.221	3.926	3.668	3.818	4.298	4.105	4.287	2.836	0.163	0.126	0.082	0.123	0.149	0.032	0.009	0.014	0.012
Ca	0.061	0.018	0.030	0.035	0.025	0.009		0.041	0.003	0.002	0.004	0.004			0.948	0.966	0.963
Na		0.012			0.013				0.018	0.039	0.084	0.041	0.034	0.159
K	0.046	0.113	0.006	0.011			0.005	0.060	0.753	0.917	0.878	0.865	0.919	0.838		0.001	0.000
T(°C)			213^¶	237^¶	348^¶	328^¶	317^¶								264	316	293
X_Mg	0.486	0.461	0.410	0.421	0.465	0.451	0.470	0.341							0.938^§	1.424^§	1.179^§
Al^IV	2.424	2.668	2.629	2.639	2.716	2.681	2.720	2.790	0.613	0.897	0.872	0.811	0.855	0.944
Al^VI	2.94	3.117	2.863	2.772	2.682	2.801	2.78	3.317	1.689	1.787	1.834	1.771	1.718	1.892
ΣOcta	11.631	11.633	11.799	11.839	11.927	11.903	11.909	11.624	1.972	1.996	1.979	1.982	1.968	1.974
K+Na									0.770	0.956	0.962	0.906	0.953	0.996
R1									0.283	0.209	0.145	0.210	0.250	0.082
R2									0.934	0.956	0.967	0.953	0.944	0.974
a1^¶			0.00036783	0.00046595	0.00092126	0.00070864	0.00090551
a2^¶			0.00244637	0.00271166	0.00431985	0.00381852	0.00460479
a3^¶			0.05127978	0.04885852	0.03564009	0.03889698	0.03319854
a4^¶			0.00762870	0.00607520	0.00310834	0.00349319	0.00420941

ΣOcta octahedral occupancy, R1 = Mn+Mg+Fe, R2 ^VIAl³/(^VIAl³ + ^VIFe³), b.d. Bleow detection limit
^* For muscovite and illite the FeO is treated as Fe₂O₃
^§ X^Cc _Mg
^¶ Calculated by Inoue et al. (2009) method, those parameters a1, a2, a3 and a4 for temperature calculation are given in the eighth decimal and their meanings refer to Inoue et al. (2009)

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