Lithological mapping in Sangan region in Northeast Iran using ASTER satellite data and image processing methods

Figures & data

Figure 1. (a) The Khaf-Kashmar-Bardskan Volcano-Plutonic Belt and Doruneh fault (Malekzadeh Shafaroudi et al., 2013); and (b) geological map of the study area and Sangan Magmatic Complex (modified after 1:250,000 geological map of Taybad, Geological Survey of Iran) (Sepidbar et al., 2018).

Table 1. ASTER spectral passband characteristics (Di Tommaso & Rubinstein, 2007).

Characteristics	Band’s Number	Spectral Bandwidth (µm)	Spatial Resolution (m)	Radiometric Resolution (bits)
VNIR	1	0.52–0.60	15	8
	2	0.63–0.69
	3N	0.78–0.80
	3B	0.78–0.86
SWIR	4	1.650–1.700	30	8
	5	2.145–2.185
	6	2.185–2.225
	7	2.235–2.285
	8	2.295–2.395
	9	2.360–2.430
TIR	10	8.125–8.475	90	12
	11	8.475–8.825
	12	8.925–9.275
	13	10.25–10.95
	14	10.95–11.65

Figure 2. FCC image based on band ratios (4/7, 3/4, 2/1 as RGB) of ASTER data.

Figure 3. FCC image based on band ratios (7/6, 6/5, 6/4 as RGB) of ASTER data.

Figure 4. FCC image based on band ratios (8/5, 5/4, 7/8 as RGB) of ASTER data.

Figure 5. SAM classification result for lithological mapping in the Sangan region.

Figure 6. Geological map at a scale of 1:20,000 of SMC based on ASTER data and field observations

Figure 7. The field photographs of the study area during field investigation. (a) Granite; (b) Sandstone and shale; (c) Dolomite; (d) Limestone.

Figure 8. Classification results achieved by SVM of ASTER data in the study area.

Table 2. Each class producer accuracy, user’ s accuracy and average accuracy of ASTER in the study area.

Class	Producer’s Accuracy	User’s Accuracy	Overall Accuracy	Kappa
Recent alluvium	70.10	72.30	79.03	0.75
Gravel fans and terraces	71.20	72.10
Conglomerate	78.30	80.25
Red conglomerate	78.90	80.25
Sandstone, shale, marl, gypsum	80.20	84.30
Tuff, volcano-sedimentary, dacite, andesite	79.20	80.10
Granite, biotite granite	82.10	83.15
Quartzite, schist	80.05	81.60
Limestone, dolomite	80.30	82.35
Debris of granite(Placer)	83.05	84.20
Debris of volcanic	73.20	75.35
Mud flat	82.30	81.90

Figure 9. The final geological map with field survey points distribution of the study area.

Malekzadeh Shafaroudi, A., Karimpour, M. H., & Golmohammadi, A. (2013). Zircon U–Pb geochronology and petrology of intrusive rocks in the C-North and Baghak districts, Sangan iron mine, NE Iran. Journal of Asian Earth Sciences, 64, 256–271.

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Sepidbar, F., Mirnejad, H., & Mi, C. (2018). Mineral chemistry and Ti in zircon thermometry: Insights into magmatic evolution of the Sangan igneous rocks, NE Iran. Journal of Chemie Der Erde.

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Di Tommaso, I., & Rubinstein, N. (2007). Hydrothermal alteration mapping using ASTER data in the infiernillo porphyry deposit, Argentina. Ore Geology Reviews, 32, 275–290.

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