Research on climate change based on carbonate porosity analysis in Jinping, China

imagej2x. Fig 4d(1), 4d(2), 4e(3) and 4e(4) show the alternative algorithm curves(four com- mon saddle line mappings of Eq (2)). Fig 4f, 4g, 4i and 4j show the alternative algorithm curves (four common saddle line mappings of Eq (2)) and the corresponding R value curves. Accord- ing to the R value curves obtained from the four saddle line mappings of Eq (2), the curve in Fig 4e(5) is the most suitable saddle line mapping for carbonate rock research. Thus, the curve in Fig 4e(5) was used in Fig 6. Fig 4h shows a new image obtained via gray-scale processing of the carbonate rock slide image using the curve in Fig 4e(5). 3 Results 3.1 Selection of saddle line mapping for the finite automata Compared with the gray-scale curve, the algorithm for obtaining the porosity and pore size of a carbonate rock from a polarized image is slightly more complicated. In this study, the finite automata algorithm was used to analyze the polarized images of the carbonate rocks. The sad- dle line map was chosen as the map of the finite automata. There are four saddle-line maps that are often used in the Jinping area (Fig 5). The principle of the saddle line is to use the RGB value and gray value of the current pixel to generate a new RGB value and gray value using the Table 1. Porosity obtained from polarized light microscope images of carbonate rocks from the Jinping area using the saddle line threshold. A B C D E F G H I J 1-1 P 1(q+m) 135 2.078 135 0.21 135 0.216 135 0.001 1-2 P 1(q+m) 135 0.553 135 0.538 135 0.375 135 0.033

1-3 P 1(q+m) 135 0.521 135 0.863 135 0.876 135 0.014 2-1 P 2β 135 0.991 135 1.074 135 0.758 135 0.012 2-2 P 2β 135 1.228 135 1.54 135 1.6 135 0.017 2-3 P 2β 135 2.427 135 1.969 135 1.312 135 0.09 3-1 P 2x 135 1.593 135 1.645 135 0.046 135 0.353 3-2 P 2x 135 4.682 135 0.211 135 0.0008 135 0.312 4-1 T 1q 135 3.165 135 2.121 135 1.054 135 0.255 4-2 T 1q 135 1.129 135 1.623 135 1.154 135 0.028 5-1 T 2b 135 2.028 135 1.462 135 1.092 135 0.027 5-2 T 2b 135 0.863 135 0.704 135 0.798 135 0.001 5-3 T 2b 135 0.324 135 0.554 135 0.577 135 0.002 6-1 T 2y 135 1.516 135 1.626 135 0.159 135 0.238 6-2 T 2y 135 4.301 135 0.281 135 0.003 135 0.249 7-1 T 2z 135 2.096 135 0.848 135 0.03 135 0.35 7-2 T 2z 135 4.147 135 0.265 135 0.0034 135 0.364 7-3 T 2z 135 5.112 135 0.427 135 0.028 135 0.335 8-1 T 3 135 5.459 135 0.278 135 0.002 135 0.283 8-2 T 3 135 1.65 135 0.615 135 0.016 135 0.311 8-3 T 3 135 5.651 135 0.321 135 0.001 135 0.348 9-1 J 1 135 6.595 135 0.374 135 0.002 135 0.19 9-2 J 1 135 5.577 135 0.31 135 0.001 135 0.125 9-3 J 1 135 5.736 135 0.254 135 0.0009 135 0.188 A: serial number; B: Strata; C: Saddle line threshold 1; D: Porosity obtained using saddle line threshold 1 (%); E: Saddle line threshold 2; F: Porosity obtained using

saddle line threshold 2 (%); G: Saddle line threshold 3; H: Porosity obtained using saddle line threshold 3 (%); I: Saddle line threshold 4; J: Porosity obtained using saddle line threshold 4 (%). https://doi.org/10.1371/journal.pone.0281630.t001 PLOS ONE Research on climate change based on carbonate porosity analysis in Jinping PLOS ONE | https://doi.org/10.1371/journal.pone.0281630 March 30, 2023 8 / 21