0 引言
1 区域地质背景
2 样品和实验
2.1 样品采集及实验方法
2.2 标准化选取
3 实验结果
3.1 岩石学特征
图3 四川盆地东部龙王庙组各类白云岩微观特征(a)泥微晶白云岩,晶体小,结构致密,单偏光,彭水板凳沟剖面(BDG-28);(b)泥微晶白云岩阴极发光特征,呈暗红色,彭水板凳沟剖面(BDG-28);(c)粉晶白云岩,半自形—自形晶,见缝合线,单偏光,习水土河剖面(TH-09);(d)粉晶白云岩阴极发光特征,呈亮红光,见微裂缝发育,习水土河剖面(TH-09);(e)细晶白云岩,半自形—他形晶,雾心亮边结构,单偏光,巫溪徐家坝剖面(XJB-27);(f)细晶白云岩阴极发光特征,“雾心”呈暗红色,“亮边”呈亮红光,巫溪徐家坝剖面(XJB-27) Fig.3 Microscopic characteristics of various dolomites of Longwangmiao Formation in eastern Sichuan Basin |
3.2 稀土元素特征
表1 研究区龙王庙组碳酸盐岩稀土元素含量及元素异常值Table 1 Rare earth element contents and abnormal values of Longwangmiao Formation in the study area |
样品编号 | 岩 性 | 稀土元素含量/10-6 | ΣREE /10-6 | Ti /10-6 | Sc /10-6 | U /10-6 | Fe/10-6 | Mn/10-6 | P/10-6 | (Nd/Yb)SN | Ce/Ce* | Eu/Eu* | Pr/Pr* | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
La | Ce | Pr | Nd | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | |||||||||||||
BDG-02 | 泥晶灰岩 | 8.09 | 15.99 | 1.98 | 7.07 | 1.38 | 0.29 | 1.33 | 0.18 | 1.02 | 0.20 | 0.49 | 0.07 | 0.41 | 0.06 | 38.54 | 1.53 | 0.77 | 0.63 | 4 623.92 | 380.42 | 100.04 | 6.01 | 6.59 | 0.98 | 0.33 |
BDG-34 | 11.83 | 24.78 | 2.91 | 10.04 | 1.87 | 0.35 | 1.81 | 0.24 | 1.36 | 0.29 | 0.72 | 0.11 | 0.65 | 0.09 | 57.03 | 2.70 | 2.57 | 0.26 | 5 269.48 | 262.65 | 100.84 | 5.38 | 6.96 | 0.87 | 0.32 | |
XJB-04 | 11.01 | 23.21 | 3.03 | 11.72 | 2.43 | 0.44 | 2.21 | 0.29 | 1.59 | 0.31 | 0.73 | 0.10 | 0.60 | 0.08 | 57.75 | 1.80 | 1.55 | 0.20 | 8 629.25 | 427.85 | 156.00 | 6.81 | 6.52 | 0.88 | 0.35 | |
XJB-08 | 8.13 | 16.09 | 2.08 | 7.46 | 1.38 | 0.26 | 1.40 | 0.18 | 1.10 | 0.23 | 0.57 | 0.08 | 0.51 | 0.07 | 39.56 | 2.79 | 0.86 | 0.10 | 1 387.38 | 150.34 | 18.36 | 5.14 | 6.41 | 0.88 | 0.35 | |
XJB-09 | 16.18 | 34.60 | 4.65 | 16.41 | 3.08 | 0.55 | 2.96 | 0.39 | 2.22 | 0.46 | 1.13 | 0.16 | 1.02 | 0.14 | 83.97 | 3.80 | 1.25 | 0.19 | 3 961.09 | 498.12 | 50.49 | 5.63 | 6.42 | 0.85 | 0.36 | |
BDG-16 | 泥微晶白云岩 | 6.43 | 16.21 | 2.26 | 8.75 | 2.26 | 0.36 | 2.30 | 0.38 | 2.33 | 0.48 | 1.16 | 0.18 | 1.14 | 0.15 | 44.38 | 2.33 | 1.69 | 0.19 | 7 451.28 | 222.33 | 50.11 | 2.69 | 6.58 | 0.73 | 0.37 |
BDG-24 | 4.16 | 9.13 | 1.19 | 4.32 | 0.88 | 0.15 | 0.82 | 0.11 | 0.63 | 0.13 | 0.32 | 0.04 | 0.27 | 0.04 | 22.19 | 1.33 | 1.62 | 0.18 | 7 473.19 | 199.05 | 86.76 | 5.68 | 6.61 | 0.84 | 0.35 | |
BDG-25 | 5.25 | 11.54 | 1.50 | 5.57 | 1.18 | 0.23 | 1.12 | 0.16 | 0.94 | 0.19 | 0.48 | 0.07 | 0.43 | 0.06 | 28.73 | 0.74 | 2.07 | 0.21 | 9 768.98 | 379.75 | 164.47 | 4.49 | 6.61 | 0.91 | 0.35 | |
BDG-26 | 11.93 | 27.95 | 3.64 | 13.66 | 3.07 | 0.55 | 2.98 | 0.43 | 2.56 | 0.53 | 1.29 | 0.18 | 1.11 | 0.15 | 70.04 | 2.60 | 0.58 | 0.43 | 8 719.63 | 563.35 | 146.26 | 4.32 | 6.76 | 0.84 | 0.35 | |
BDG-27 | 5.45 | 12.56 | 1.64 | 6.15 | 1.40 | 0.27 | 1.41 | 0.22 | 1.31 | 0.27 | 0.63 | 0.09 | 0.52 | 0.07 | 32.00 | 2.33 | 2.38 | 0.33 | 10 321.79 | 260.29 | 150.91 | 4.16 | 6.69 | 0.90 | 0.35 | |
BDG-28 | 3.43 | 8.24 | 1.12 | 4.30 | 1.04 | 0.21 | 1.06 | 0.17 | 1.06 | 0.22 | 0.51 | 0.07 | 0.40 | 0.05 | 21.89 | 2.13 | 2.02 | 0.50 | 10 591.87 | 387.41 | 132.68 | 3.74 | 6.61 | 0.95 | 0.36 | |
BDG-30 | 6.53 | 14.41 | 1.83 | 6.70 | 1.37 | 0.28 | 1.28 | 0.18 | 1.02 | 0.21 | 0.50 | 0.07 | 0.44 | 0.06 | 34.89 | 2.50 | 2.33 | 0.40 | 3 888.30 | 304.62 | 77.81 | 5.39 | 6.72 | 0.98 | 0.34 | |
XJB-24 | 10.86 | 22.53 | 2.75 | 9.73 | 1.94 | 0.36 | 1.86 | 0.25 | 1.45 | 0.31 | 0.77 | 0.11 | 0.70 | 0.10 | 53.72 | 3.15 | 0.88 | 0.49 | 1 921.82 | 325.44 | 82.66 | 4.87 | 6.76 | 0.87 | 0.33 | |
XJB-30 | 12.81 | 25.83 | 3.14 | 11.14 | 2.15 | 0.38 | 1.98 | 0.26 | 1.43 | 0.30 | 0.75 | 0.10 | 0.65 | 0.09 | 61.00 | 7.52 | 1.54 | 0.47 | 1 027.01 | 432.88 | 27.58 | 6.03 | 6.72 | 0.86 | 0.33 | |
XJB-35 | 5.05 | 10.01 | 1.15 | 4.04 | 0.74 | 0.15 | 0.73 | 0.10 | 0.54 | 0.11 | 0.27 | 0.04 | 0.22 | 0.04 | 23.18 | 2.72 | 0.69 | 0.25 | 853.03 | 178.78 | 27.43 | 6.40 | 6.92 | 0.93 | 0.31 | |
XJB-40 | 10.41 | 22.93 | 2.92 | 10.57 | 2.06 | 0.40 | 1.91 | 0.25 | 1.43 | 0.29 | 0.69 | 0.10 | 0.61 | 0.09 | 54.66 | 6.00 | 1.30 | 0.38 | 3 593.35 | 223.35 | 81.92 | 6.12 | 6.71 | 0.93 | 0.34 | |
TH-15 | 6.39 | 12.83 | 1.53 | 5.43 | 1.05 | 0.19 | 0.99 | 0.13 | 0.77 | 0.16 | 0.37 | 0.05 | 0.31 | 0.05 | 30.26 | 2.88 | 1.93 | 0.43 | 7 483.92 | 139.50 | 135.47 | 6.12 | 6.77 | 0.85 | 0.32 | |
BDG-31 | 粉晶白云岩 | 3.28 | 6.56 | 0.85 | 3.02 | 0.59 | 0.14 | 0.55 | 0.07 | 0.41 | 0.08 | 0.20 | 0.03 | 0.18 | 0.02 | 15.99 | 1.56 | 0.88 | 0.53 | 3 884.15 | 140.54 | 54.95 | 6.00 | 6.41 | 1.12 | 0.35 |
XJB-12 | 7.88 | 14.84 | 1.78 | 6.26 | 1.16 | 0.24 | 1.18 | 0.16 | 0.94 | 0.20 | 0.49 | 0.07 | 0.40 | 0.06 | 35.67 | 7.14 | 1.60 | 0.66 | 1 678.83 | 404.52 | 22.95 | 5.44 | 6.59 | 0.96 | 0.33 | |
XJB-25 | 2.53 | 5.37 | 0.63 | 2.20 | 0.42 | 0.08 | 0.41 | 0.05 | 0.32 | 0.07 | 0.16 | 0.02 | 0.14 | 0.02 | 12.43 | 1.30 | 0.53 | 0.39 | 2 421.42 | 99.24 | 18.37 | 5.38 | 6.99 | 0.90 | 0.32 | |
XJB-36 | 2.36 | 4.64 | 0.58 | 2.00 | 0.39 | 0.08 | 0.38 | 0.05 | 0.29 | 0.06 | 0.15 | 0.02 | 0.13 | 0.02 | 11.15 | 1.78 | 0.32 | 0.33 | 989.78 | 99.15 | 13.70 | 5.59 | 6.52 | 0.90 | 0.34 | |
XJB-37 | 3.44 | 7.02 | 0.82 | 2.79 | 0.48 | 0.09 | 0.49 | 0.06 | 0.38 | 0.08 | 0.20 | 0.03 | 0.18 | 0.03 | 16.09 | 2.63 | 0.50 | 0.33 | 1 236.17 | 200.96 | 9.13 | 5.57 | 6.94 | 0.91 | 0.32 | |
XJB-38 | 2.82 | 5.75 | 0.71 | 2.50 | 0.48 | 0.09 | 0.46 | 0.06 | 0.37 | 0.08 | 0.19 | 0.03 | 0.17 | 0.03 | 13.73 | 1.23 | 0.42 | 0.43 | 2 536.73 | 90.69 | 31.90 | 5.22 | 6.70 | 0.91 | 0.33 | |
TH-02 | 5.66 | 10.93 | 1.30 | 4.53 | 0.82 | 0.17 | 0.83 | 0.11 | 0.66 | 0.14 | 0.34 | 0.05 | 0.29 | 0.04 | 25.88 | 1.15 | 0.26 | 0.56 | 3 533.13 | 463.19 | 13.60 | 5.48 | 6.70 | 0.94 | 0.32 | |
TH-04 | 5.58 | 10.70 | 1.32 | 4.64 | 0.87 | 0.19 | 0.87 | 0.12 | 0.68 | 0.14 | 0.34 | 0.05 | 0.29 | 0.04 | 25.83 | 1.11 | 0.58 | 0.44 | 5 470.66 | 485.79 | 31.70 | 5.61 | 6.54 | 1.01 | 0.33 | |
TH-06 | 5.62 | 10.82 | 1.31 | 4.58 | 0.85 | 0.18 | 0.85 | 0.11 | 0.67 | 0.14 | 0.34 | 0.05 | 0.29 | 0.04 | 25.85 | 1.83 | 0.24 | 0.53 | 3 597.24 | 481.88 | 18.07 | 5.54 | 6.62 | 0.98 | 0.33 | |
TH-14 | 5.14 | 10.02 | 1.31 | 4.71 | 0.90 | 0.18 | 0.85 | 0.11 | 0.63 | 0.13 | 0.31 | 0.04 | 0.27 | 0.04 | 24.65 | 6.59 | 1.73 | 0.65 | 2 355.02 | 479.39 | 13.55 | 6.12 | 6.34 | 0.96 | 0.35 | |
XJB-27 | 细晶白云岩 | 6.77 | 12.71 | 1.61 | 5.53 | 0.99 | 0.18 | 0.91 | 0.11 | 0.62 | 0.13 | 0.30 | 0.04 | 0.27 | 0.04 | 30.21 | 4.44 | 1.61 | 0.87 | 1 464.09 | 306.38 | 18.38 | 7.15 | 6.36 | 0.86 | 0.34 |
XJB-39 | 5.39 | 10.02 | 1.22 | 4.22 | 0.76 | 0.12 | 0.68 | 0.09 | 0.46 | 0.10 | 0.23 | 0.03 | 0.20 | 0.03 | 23.55 | 3.10 | 0.90 | 0.84 | 1 472.80 | 116.93 | 9.11 | 7.46 | 6.50 | 0.80 | 0.33 | |
XJB-42 | 7.48 | 14.84 | 1.91 | 6.62 | 1.23 | 0.23 | 1.20 | 0.17 | 0.95 | 0.21 | 0.49 | 0.07 | 0.42 | 0.06 | 35.86 | 10.85 | 1.00 | 0.79 | 1 523.75 | 626.25 | 13.63 | 5.55 | 6.44 | 0.87 | 0.35 | |
XJB-43 | 2.22 | 4.77 | 0.57 | 1.98 | 0.36 | 0.07 | 0.36 | 0.05 | 0.28 | 0.06 | 0.14 | 0.02 | 0.12 | 0.02 | 11.03 | 3.64 | 0.28 | 0.58 | 1 577.08 | 147.75 | 9.08 | 5.85 | 6.93 | 0.90 | 0.33 | |
TH-03 | 3.81 | 7.39 | 0.89 | 3.10 | 0.56 | 0.10 | 0.52 | 0.07 | 0.37 | 0.08 | 0.19 | 0.03 | 0.16 | 0.02 | 17.29 | 2.23 | 0.51 | 0.75 | 3 997.48 | 974.69 | 4.53 | 6.85 | 6.64 | 0.83 | 0.33 | |
TH-07 | 4.17 | 8.06 | 1.00 | 3.49 | 0.63 | 0.11 | 0.60 | 0.08 | 0.43 | 0.09 | 0.22 | 0.03 | 0.19 | 0.03 | 19.13 | 1.01 | 0.39 | 0.61 | 3 956.51 | 493.14 | 13.54 | 6.46 | 6.53 | 0.83 | 0.33 | |
TH-08 | 4.60 | 8.71 | 1.06 | 3.66 | 0.66 | 0.11 | 0.60 | 0.08 | 0.42 | 0.09 | 0.21 | 0.03 | 0.18 | 0.03 | 20.42 | 1.37 | 0.29 | 0.42 | 3 489.95 | 407.29 | 0.00 | 7.19 | 6.56 | 0.81 | 0.33 | |
TH-09 | 4.20 | 8.05 | 0.98 | 3.38 | 0.61 | 0.10 | 0.56 | 0.07 | 0.40 | 0.08 | 0.20 | 0.03 | 0.17 | 0.03 | 18.85 | 1.20 | 0.27 | 0.41 | 4 374.76 | 370.64 | 9.03 | 7.03 | 6.59 | 0.82 | 0.33 | |
TH-10 | 3.67 | 7.44 | 0.99 | 3.53 | 0.65 | 0.12 | 0.67 | 0.09 | 0.53 | 0.11 | 0.28 | 0.04 | 0.24 | 0.04 | 18.40 | 2.40 | 0.93 | 0.63 | 2 371.95 | 620.72 | 9.03 | 5.11 | 6.36 | 0.85 | 0.35 | |
TH-11 | 2.95 | 6.10 | 0.78 | 2.75 | 0.51 | 0.10 | 0.52 | 0.07 | 0.41 | 0.09 | 0.21 | 0.03 | 0.18 | 0.03 | 14.71 | 2.32 | 0.42 | 0.54 | 4 739.43 | 634.08 | 4.51 | 5.35 | 6.57 | 0.87 | 0.34 | |
TH-12 | 3.31 | 6.77 | 0.88 | 3.14 | 0.58 | 0.11 | 0.59 | 0.08 | 0.47 | 0.10 | 0.24 | 0.04 | 0.21 | 0.04 | 16.56 | 0.96 | 0.26 | 0.59 | 2 898.12 | 662.31 | 4.51 | 5.22 | 6.45 | 0.86 | 0.35 |