Laser ablation in situ U-Pb dating and its application to diagenesis-porosity evolution of carbonate reservoirs

SHEN Anjiang,HU Anping,CHENG Ting,LIANG Feng,PAN Wenqing,FENG Yuexing,ZHAO Jianxin

Table 3 U-Pb isotopic ages and geochemical characteristics of surrounding rocks and dolomite cements[19].

Sample No. Sample occurrence Isotopic age/Ma Cathodeluminescence Geochemical characteristics D47 or homogenization temperature of inclusion/°C Isotopic composition/‰ O C XF-Z2dn2-S4 Surrounding rocks 584±32 Nonluminous -4 - -1 1-3 GC-Z2dn2-B3 592±24 XF-Z2dn2-S5 Concentric ring-edge dolomite cement 546±7.6 Nonluminous 63.9(D47) -6 - -4 1-3 YB-Z2dn2-B2 545±6 GC-Z2dn2-B5 545±12 XF-Z2dn2-S4 Radial dolomite cement 516±10 Dark orange dim luminescence 91.2(D47) -8 - -6 2-4 GC-Z2dn2-B4 514±14 XF-Z2dn2-S4 Layered light grey-dark dolomite cement 482±14 Orange yellow medium luminescence 135(D47) -10 - -8 2-4 YB-Z2dn2-B2 487±21 GC-Z2dn2-B5 Medium-coarse crystalline dolomite cement 248±27 Orange yellow bright luminescence 185 (inclusion) -12 - -9 1-2 XF-Z2dn1-B2 20±130 220 (inclusion) GC-Z2dn2-B3 115±69 GS6-Z2d2-1 Equiaxed granular dolomite cements filling pores 545.7±8.5 Nonluminous 71.6(D47) -5 - -3 1-3 MX22-Z2d2-2 Leaf-like dolomite cement 499±25 Dim luminescence 89.3(D47) -8 - -4 0-2 MX8-Z2d4-1 Medium-coarse crystalline dolomite cement 457±17 Orange yellow medium luminescence 127.5(D47) -15 - -9 -2-2 MX22-Z2d2-3 468±12 XF-Z2d1-B2 Dolomite cement filling fractures 20±130 Orange yellow medium luminescence 175—225 (D47) GS1-Z2d4-2 41±10 MX9-Z2d2-1 41±35 MX22-Z2d2-4 Dolomite cement filling fractures 472±21