Assessment of Gold Mineralization Potential along the Khonsar–Aligudarz belt, with Emphasis on the Darreh Sari Area, Using Factor Analysis and Geological Evidence

Shahin, Mina; Alaminia, Zahra; Hoseinzade, Zohre; Tabatabaei Manesh, Seyed Mohsen; Mahmoodi, Pouria

doi:10.22067/econg.2026.1182

Assessment of Gold Mineralization Potential along the Khonsar–Aligudarz belt, with Emphasis on the Darreh Sari Area, Using Factor Analysis and Geological Evidence

Document Type : Research Article

Authors

Mina Shahin ¹

Zahra Alaminia ²

Zohre Hoseinzade ³

Seyed Mohsen Tabatabaei Manesh ⁴

Pouria Mahmoodi ⁵

¹ Ph.D. Candidate, Department of Geology, Faculty of Science, University of Isfahan, Isfahan, Iran

² Associate Professor, Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran

³ Assistant Professor, Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran

⁴ Professor, Department of Geology, Faculty of Science, University of Isfahan, Isfahan, Iran

⁵ Ph.D. Iran Mineral Production and Supply Company (IMPASCO), Tehran, Iran

10.22067/econg.2026.1182

Abstract

Assessment of gold mineralization potential in metamorphic terrains requires the application of effective analytical approaches because geochemical patterns are simultaneously influenced by lithological variability, hydrothermal alteration, and structural complexity. In this study, the gold mineralization potential along the Khonsar-Aligudarz belt was evaluated by integrating factor analysis with geological evidence. For this purpose, stream-sediment data from the Golpayegan and Aligudarz 1:100000 geochemical sheets were processed, and inter-element relationships were investigated. The results indicate that factor analysis successfully separated the component related to gold mineralization from the regional lithological background and delineated areas with the highest mineralization potential. Validation of the results through field investigations, petrographic studies, and mineralogical examinations in the Darreh Sari area confirmed the presence of NW-SE trending quartz–hematite–bearing vein-veinlets containing pyrite, pyrrhotite, arsenopyrite, marcasite, chalcopyrite, sphalerite, and galena, as well as iron-, manganese-, and copper-oxide minerals, including hematite, goethite, and, less commonly, magnetite, pyrolusite, and malachite, within Triassic–Jurassic schists and metapelites. The close correspondence between the geochemical anomalies and shear zones and quartz veins indicates that these structures played a major role in channeling mineralizing fluids and concentrating gold. The results of this study indicate that integrating factor analysis with geological information provides an effective approach for reducing uncertainty in regional exploration and prioritizing gold exploration targets in the central Sanandaj–Sirjan Zone and other comparable metamorphic environments.

Introduction
Gold, as one of the most important strategic and economic metals, forms within a wide range of hydrothermal and orogenic systems, and delineating prospective zones for its occurrence remains a central objective of mineral exploration. In the central Sanandaj–Sirjan Zone, between Khonsar and Aligudarz, several gold occurrences (e.g., Darreh Sari, Hasan Abad, Reza Abad, Hossein Abad, Koucheri, and Sefidsang) have been documented within Triassic–Jurassic schists and metapelites, typically as quartz vein-veinlets with iron and base-metal sulfides and associated silicification, chloritization, carbonatization, and oxidation. Structural control by brittle–ductile shear zones, combined with hydrothermal fluid–rock interaction, has played a fundamental role in concentrating gold and base metals in this belt. Despite reasonable knowledge of these occurrences' geology and mineralogy, regional evaluation of geochemical dispersion patterns remains challenging, since differential element behavior during weathering and transport produces complex, overlapping anomalies that single-element interpretation cannot reliably resolve.
Stream sediment geochemistry is among the most effective, economical regional exploration methods for detecting concealed mineralization, though its performance depends heavily on data processing. Conventional univariate threshold methods generally fail to reveal complex inter-element relationships or separate signals from different mineralizing systems, whereas multivariate statistics, particularly factor analysis, overcome this limitation by extracting independent geochemical factors and hidden correlations, distinguishing gold-related components from lithological background or polymetallic systems and improving the accuracy of potential maps. Within this framework, the Darreh Sari area, southwest of Golpayegan and southeast of Aligudarz, was delineated as a gold anomaly from stream sediment data; subsequent field work confirmed quartz–hematite veins- veinlets within Triassic–Jurassic schists accompanied by iron and base-metal sulfides, indicating a gold-bearing hydrothermal system. This study integrates stream sediment geochemistry, factor analysis, and field, petrographic, and mineragraphic evidence to evaluate gold potential along the Khonsar–Aligudarz axis, providing a practical framework for targeted exploration in comparable metamorphic terrains.

Geological setting
The study area lies in the central Sanandaj–Sirjan metamorphic-structural zone, one of Iran's principal metamorphic-magmatic and metallogenic belts, whose evolution is generally attributed to Paleo-Tethys closure and prolonged Neo-Tethyan subduction beneath Central Iran from the Late Triassic to the Cenozoic, accompanied by magmatism, regional metamorphism, and polyphase deformation; an alternative model instead links part of the Mesozoic magmatism to intracontinental rifting. The belt mainly comprises Mesozoic sedimentary–volcanic sequences metamorphosed under greenschist- to amphibolite-facies conditions, producing slate, phyllite, quartzite, schist, amphibolite, and gneiss. In the central sector, Triassic–Jurassic phyllite–schist sequences are cut by numerous shear zones and faults that, with hydrothermal circulation and quartz veining, principally control mineralization.

Materials and methods
Geochemical data from 947 stream sediment samples covering ~1,419 km² across the Golpayegan and Aligudarz 1:100000 sheets (Mohajjel and Eftekhar Nezhad, 1992; Soheili et al., 1992), previously analyzed by inductively coupled plasma spectrometry and archived by the Geological Survey and Mineral Exploration Organization of Iran, were used. Concentrations of Cu, Pb, Zn, Ba, B, Co, Cr, Mn, Ni, Sc, Sr, V, and Y were evaluated via descriptive statistics, frequency and box plots, and factor analysis with varimax rotation on standardized data to extract mineralization-related factors and construct factor-score maps. The previously undocumented Darreh Sari anomaly was investigated over two field campaigns documenting mineralized outcrops, and alteration zones, sampled for petrographic and mineragraphic study; five rock-chip samples from two gold-bearing veins were analyzed for gold grade by Fire Assay.

Results
Stream Sediment Geochemistry Results
Stream sediment concentrations show wide ranges reflecting catchment-scale geochemical heterogeneity. Co and Ni display the most uniform distributions, consistent with lithological control, whereas B (CV = 73.4%) and Mn (CV = 94.1%) show the greatest dispersion, reflecting hydrothermal alteration or oxide concentration; Pb shows the highest variability among base metals (CV = 59.3%), suggesting local sulfide enrichment. Factor analysis extracted six factors: lithological (Sc–Y–V), mafic (Ni–Cr–Co), mineralization (Pb–Zn–Mn), alteration (B–Ba), carbonate (Sr), and magmatic-hydrothermal (Cu). The mineralization factor-score map shows pronounced anomalies at the Reza Abad, Hasan Abad, and Takht-e Khosrow occurrences, plus a distinct NW–SE-trending anomaly at Darreh Sari matching the vein orientation; all anomalies are confined to the Triassic–Jurassic greenschist unit, confirming its role in mineralization.
At Darreh Sari, local geology comprises Precambrian mica schists with metarhyolite intercalations, Triassic–Jurassic units (marble, black shale, slate, phyllite, schist), granodioritic intrusions, and Quaternary deposits. The intensely fractured, thrust-bounded metamorphic units favored quartz-vein emplacement, while carbonaceous black shales likely supplied sulfur and gold. Gold occurs mainly as two NW–SE-trending silicic veins (~990 m long, ~2 m wide) parallel to host-rock schistosity, locally cut by younger veinlets indicating post-mineralization reactivation. Fire Assay of five samples yielded gold grades of 87, 1051, 2591, and 5256 mg/t east to west along the main vein and 557 mg/t in a subsidiary vein, with the highest grades in the west matching the strongest anomaly and confirming economic mineralization. Mineragraphic study shows abundant multi-generation pyrite and pyrrhotite, accessory arsenopyrite, marcasite, chalcopyrite, sphalerite, and galena as intergrowths and cavity fillings, subordinate early-stage magnetite, and colloform marcasite, consistent with a hydrothermal quartz-vein system corroborating the geochemical model.

Discussion
Gold mineralization at Darreh Sari developed within a Sanandaj–Sirjan segment shaped by Neo-Tethyan convergence, regional metamorphism, and crustal-scale shear zones. Factor analysis effectively separated lithological background (Factors 1, 2) from mineralization-related components (Factors 3, 6), which form discrete anomalies independent of lithological boundaries and spatially linked to alteration, confirming the superiority of multivariate over single-element interpretation in structurally complex terrains. The close correspondence between anomalies, shear zones, and quartz veins indicates that brittle–ductile structures were the primary conduits for mineralizing fluids, consistent with structural controls documented for the Muteh gold belt and other orogenic systems of the zone. The paragenetic sequence, pyrite and pyrrhotite followed by base-metal sulfides, reflects progressive evolution of a multistage hydrothermal system consistent with orogenic gold models. Carbon-rich host rocks likely contributed sulfur, CO₂, and metals through devolatilization, consistent with models in which organic matter scavenges, transports, and helps precipitate gold via fluid reduction. Surface hematitic staining likely reflects supergene oxidation, yet the coherent anomalies indicate the primary hydrothermal signal survived weathering. These results confirm that multivariate analysis of stream sediment data reveals hydrothermal signals in complex terrains, and that integrating it with structural and remote-sensing data effectively reduces exploration uncertainty and prioritizes drilling targets.

Conclusion
This study demonstrates that factor analysis of stream sediment geochemical data, integrated with geological and mineragraphic evidence, effectively identifies gold-related anomalies in the Darreh Sari area and along the Khonsar–Aligudarz belt. Separating lithological components from hydrothermal signals enabled recognition of genuine mineralization-related anomalies, whose strong correspondence with NW–SE-trending shear zones, quartz veins, and Triassic–Jurassic metamorphic units confirm the key role of structural controls in channeling fluids and concentrating gold. Consistency between geochemical and field/mineragraphic observations validates a structurally controlled hydrothermal model, offering an efficient framework for prioritizing exploration targets and reducing uncertainty in early-stage gold exploration across comparable settings of the Sanandaj–Sirjan Zone.

Keywords

Gold

factor analysis

geochemistry of stream sediments

Sanandaj- Sirjan Zone

mineralization potential

Abdollahi, M.J., Karimpour, M.H., Kheradmand, A. and Zarasvandi, A.R., 2009. Stable isotopes (O, H, and S) in the Muteh gold deposit, Golpaygan area, Iran. Natural Resources Research, 18: 137–151. https://doi.org/10.1007/s11053-009-9091-3

Alavi, M., 1996. Tectono- stratigraphic synthesis and structural style of the Alborz Mountain system in Northern Iran. Journal of Geodynamics, 21(1): 1–33. https://doi.org/10.1016/0264-3707(95)00009-7

Alirezaei, S. and Hassanzadeh, J., 2012. Geochemistry and zircon geochronology of the Permian A-type Hasanrobat granite, Sanandaj- Sirjan belt: A new record of the Gondwana break-up in Iran. Lithos, 151: 122–134. https://doi.org/10.1016/j.lithos.2011.11.015

Aliyari, F., Rastad, E., Goldfarb, R.J. and Sharif, J.A., 2014. Geochemistry of hydrothermal alteration at the Qolqoleh gold deposit, northern Sanandaj- Sirjan metamorphic belt, northwestern Iran: Vectors to high- grade ore bodies. Journal of Geochemical Exploration, 140: 111–125. https://doi.org/10.1016/j.gexplo.2014.01.007

Aliyari, F., Rastad, E. and Mohajjel, M., 2012. Gold deposits in the Saanandaj- Sirjan zone: orogenic gold deposits or intrusion- related gold system? Resource Geology, 62‌(3): 296–315. https://doi.org/10.1111/j.1751-3928.2012.00196.x

Azizi, H. and Stern, R.J., 2019. Jurassic igneous rocks of the central Sanandaj- Sirjan zone (Iran) mark a propagating continental rift, not a magmatic arc. Terra Nova, 31(5): 415–423. https://doi.org/10.1111/ter.12404

Babaahmadi, A., Davoudian, A.R. and Mohajjel, M., 2021. Transpression in the Sanandaj-Sirjan zone (Zagros Orogen, Iran) during the Jurassic and Early Cretaceous: Evidence from the north Shahrekord shear zone. Journal of Structural Geology, 149: 104387.

https://doi.org/10.1016/j.jsg.2021.104387

Bagheri, S. and Stampfli, G.M., 2008. The Anarak, Jandaq and Posht-e -Badam metamorphic complexes in central Iran: New geological data, relationships and tectonic implications. Tectonophysics, 451(1–4): 123–155.

https://doi.org/10.1016/j.tecto.2007.11.047

Behera, S. and Panigrahi, M.K., 2021. Gold prospectivity mapping in the Sonakhan Greenstone Belt, Central India: A knowledge- driven guide for target delineation in a region of low exploration maturity. Natural Resources Research, 30(6): 4009–4045.

https://doi.org/10.1007/s11053-021-09962-x

Carranza, E.J.M., 2008. Geochemical anomaly and mineral prospectivity mapping in GIS. V. 11. Elsevier, Amsterdam, 368 pp. Retrieved September 27, 2026 from https://www.sciencedirect.com/handbook/handbook-of-exploration-and-environmental-geochemistry/vol/11/suppl/C

Derikvand, S., 2022. Strain pattern and vorticity analysis in the transpressional Kamandan area within the Sanandaj- Sirjan Metamorphic Belt, Iran. Journal of Structural Geology, 158: 104595. https://doi.org/10.1016/j.jsg.2022.104595

Esmaeiloghli, S., Tabatabaei, S.H., Carranza, E.J.M., Hosseini, S. and Deville, Y., 2021. Spatially- weighted factor analysis for extraction of source- oriented mineralization feature in 3D coordinates of surface geochemical signal. Natural Resources Research, 30(6): 3925–3953.

https://doi.org/10.1007/s11053-021-09933-2

Esna- Ashari, A., Tiepolo, M., Valizadeh, M.V., Hassanzadeh, J. and Sepahi, A.A., 2012. Geochemistry and zircon U–Pb geochronology of Aligoodarz granitoid complex, Sanandaj-Sirjan zone, Iran. Journal of Asian Earth Sciences, 43(1): 11–22.

https://doi.org/10.1016/j.jseaes.2011.09.001

Fazeli Oladi, A. and Zamanian, H., 2024. Invers modeling and interpretation of magnetic and geoelectrical data in the gold area of Hassan abad (south of Golpayegan). Advanced Applied Geology, 14(2): 556–577.

https://doi.org/10.22055/aag.2024.44283.2393

Fletcher, W.K., 1997. Stream sediment geochemistry in today's exploration world. Exploration Geochemistry, (32): 249–260. Retrieved September 22, 2026 from https://www.semanticscholar.org/paper/Stream Sediment- Geochemistry-in-Today-%E2%80%99-s-World-Fletcher/4cecf9ee97c7effd1df13b9cf77c3450b435898e

Goldfarb, R.J. and Groves, D.I., 2015. Orogenic gold: Common or evolving fluid and metal sources through time. Lithos, 233: 2–26. https://doi.org/10.1016/j.lithos.2015.07.011

Goldfarb, R.J. and Pitcairn, I., 2023. Orogenic gold: is a genetic association with magmatism realistic? Mineralium Deposita, 58(1): 5–35. https://doi.org/10.1007/s00126-022-01146-8

Groves, D.I., Santosh, M., Deng, J., Wang, Q., Yang, L. and Zhang, L., 2020. A holistic model for the origin of orogenic gold deposits and its implications for exploration. Mineralium Deposita, 55(2): 275–292.

https://doi.org/10.1007/s00126-019-00877-5

Hale, M. and Plant, J.A., 1994. Handbook of Exploration Geochemistry. Drainage geochemistry, V. 6. ELSEVIER Amsterdam, 766 pp. Retrieved September 22, 2026 from https://www.sciencedirect.com/handbook/handbook-of-exploration-geochemistry/vol/6/suppl/C

Helba, H.A., Khalil, K.I., El-Farnawany, H.M. and El-Raghy, S.A., 2021. Stream sediment geochemical exploration for gold in Central Eastern Desert, Egypt: Application of the concentration-number fractal model, factor analysis, and geochemical mineralization probability index. Geochemistry, 81(4): 125811. https://doi.org/10.1016/j.chemer.2021.125811

Hemmati, O., Tabatabaei Manesh, S.M. and Nadimi, A.R., 2018. Deformation mechanism of Darreh Sari metapelites Sanandaj- Sirjan zone, Iran. Geotectonic, 52(2): 281–296.

https://doi.org/10.1134/S0016852118020024

Horton, B.K., J., Hassanzadeh, D.F., Stockli, G.J., Axen, R.J., Gillis, B., Guest, A., Amini, M.D., Fakhari, S., Zamanzadeh, M. and Grove, M., 2008. Detrital zircon provenance of Neoproterozoic to Cenozoic deposits in Iran: Implications for chronostratigraphy and collisional tectonics, Tectonophysics, 451(1–4): 97–122. https://doi.org/10.1016/j.tecto.2007.11.063

Karimi, S. and Tabatabaei Manesh, S.M. 2016. Textural relations, P-T path, polymetamorphism and also geodynamic significance of metamorphic rocks of the Aligudarz- Khansar region, Sanandaj- Sirjan zone, Iran. Petrology, 24(1): 100–115.

https://doi.org/10.1134/S086959111506003X

Kouhestani, H., Rashidnejad Omran, N., Rastad, E., Mohajjel, M., Goldfarb, R.J. and Ghaderi, M., 2014. Orogenic gold mineralization at the Chah Bagh deposit, Muteh gold district, Iran. Journal of Asian Earth Sciences, 91: 89–106. https://doi.org/10.1016/j.jseaes.2014.04.027

Madanipour, S., Yassaghi, A., Ehlers, T.A. and Enkelmann, E., 2018. Tectonostratigraphy, structural geometry and kinematics of the NW Iranian Plateau margin: insights from the Talesh Mountains, Iran. American Journal of Science, 318(2): 208–245.

https://doi.org/10.2475/02.2018.02

Madden, D.J. and Tripp, R.B., 1987. Geochemical signatures of mineral deposits and rock types as shown in stream sediments from the Chugach and Prince William terranes, Anchorage Quadrangle, southern Alaska. U.S. Geological Survey, Open-File Report, Report No. 87–131. 8 pp. https://doi.org/10.3133/ofr87131

Mehrabi, B., Tale Fazel, E. and Shahabifar, M., 2012. Ore mineralogy and fluid inclusions constraints on genesis of the Muteh gold deposit (western Iran). Geopersia, 2(1): 67–90.

https://doi.org/10.22059/jgeope.2012.24802

Mohajjel, M. and Eftekhar Nezhad, J., 1992. Geological map of Golpayegan, scale 1:100,000. Geological Surver of Iran.

Mohajjel, M. and Fergusson, C.L., 2000. Dextral transpression in Late Cretaceous continental collision, Sanandaj-Sirjan zone, western Iran. Journal of Structural Geology, 22(8): 1125–1139. https://doi.org/10.1016/S0191-8141(00)00023-7

Moritz, R., Ghazban, F. and Singer, B.S., 2006. Eocene gold ore formation at Muteh, Sanandaj- Sirjan tectonic zone, Western Iran: a result of late- stage extension and exhumation of metamorphic basement rocks within the Zagros Orogen. Economic geology, 101(8): 1497–1524. https://doi.org/10.2113/gsecongeo.101.8.1497

Ouchchen, M., Boutaleb, S., Abia, E.H., El Azzab, D., Miftah, A., Dadi, B., Echogdali, F.Z., Mamouch, Y., Pradhan, B., Santosh, M. and Abioui, M., 2022. Exploration targeting of copper deposits using staged factor analysis, geochemical mineralization prospectivity index, and fractal model (Western Anti- Atlas, Morocco). Ore Geology Reviews, 143: 104762. https://doi.org/10.1016/j.oregeorev.2022.104762

Rashidnejad-Omran, N., 2002. Petrology and geochemistry of the volcano- sedimentary and plutonic rocks of the south of the Delijan, concentration on gold mineralization. Ph.D. Thesis, Tarbiat Moddares University, Tehran, Iran. 160 pp

Rose, A.W., Hawkes, H.E. and Webb, J.S., 1979. Geochemistry in Mineral Exploration. Academic Press, London, 637 pp.

Sadati, S.N., Nourian Ramsheh, Z. and Yazdi, M., 2022. Genesis and nature of ore-forming fluids in the Senjedeh gold mine, Central Iran; using microthermometry study. Advanced Applied Geology, 11(4): 753–769.

https://doi.org/10.22055/AAG.2020.28994.1961

Sadeghi, M., Billay, A. and Carranza, E.J.M., 2015. Analysis and mapping of soil geochemical anomalies: Implications for bedrock mapping and gold exploration in Giyani area, South Africa. Journal of Geochemical Exploration, 154: 180–193. https://doi.org/10.1016/j.gexplo.2014.11.018

Sakhdari, M., Behzadi, M., Yazdi, M., Rachidnejad-Omran, N. and Sadeghi Naeini, M., 2021. Geology, Mineralization and Geochemistry of Au in the Godar Sorkh area, Muteh region, Sanandaj-Sirjan zone. Journal of Economic Geology, 13(2): 245–265. (in Persian with English abstract) https://doi.org/10.22067/econg.v13i2.85427

Schwertman, N.C. and de Silva, R., 2007. Identifying outliers with sequential fences. Computational statistics and data analysis, 51(8): 3800–3810. https://doi.org/10.1016/j.csda.2006.01.019

Shakerardakani, F., Neubauer, F., Masoudi, F., Mehrabi, B., Monfaredi, B. and Friedl, G., 2015. Tectonic history of the central Sanandaj- Sirjan zone, Iran: Potentially Permian to Mesozoic polymetamorphism and implications for tectonics of the Sanandaj- Sirjan zone. Geophysical Research Abstracts, 17: 2015-6474. Retrieved September 22, 2026 from https://uni-salzburg.elsevierpure.com/en/publications/tectonic-history-of-the-central-sanandaj-sirjan-zone-iran-potenti-2/

Shakerardakani, F., Xiao, W., Shafaii Moghadam, H. and Li, X., 2025. Cadomian Magmatism in the Muteh–Golpaygan Area, Iran: Insights into Crustal Growth and Tectono-Magmatic Evolution. Minerals, 15(3): 201. https://doi.org/10.3390/min15030201

Soheili, M., Jafarian, M.B. and Abdollahi, M.R., 1992. Geological map of Aligudarz, scale 1:100,000. Geological Surver of Iran.

Stampfli, G., Marcoux J. and Baud, A., 1991. Tethyan margins in space and time. Palaeogeography, Palaeoclimatology, Palaeoecology, 87(1–4): 373–409. https://doi.org/10.1016/0031-0182(91)90142-E

Stern, R., Shafaii Moghadam, H., Pirouzi, M. and Mooney, W., 2021. The geodynamic evolution of Iran. Annual Review of Earth and Planetary Sciences, 49: 9–36.

https://doi.org/10.1146/annurev-earth-071620-052109

Tabatabaei Manesh, S.M., Mirlohi, A.S. and Movahedi, M., 2011. Petrology and mineral chemistry of Ochestan granitoids (south of Mahallat, Markazi province). Petrological Journal, 2(7), 51-74. Retrieved September 22, 2026 from https://www.magiran.com/paper/997901/petrology-and-mineral-chemistry-of-ochestan-granitoids-south-of-mahallat-markazi-province?lang=en

Tukey, J., 1997. More honest foundations for data analysis. Journal of Statistical Planning and Inference, 57(1): 21–28.

https://doi.org/10.1016/S0378-3758(96)00032-8

Whitney, D.L. and Evans, B.W., 2010. Abbreviations for Names of Rock-Forming Minerals. American Mineralogist, 95(1): 185–187.

http://dx.doi.org/10.2138/am.2010.3371

Yilmaz, H., 2007. Stream sediment geochemical exploration for gold in the Kazdag Dome in the Biga Peninsula, Western Turkey. Turkish Journal of Earth Sciences, 16(1): 33–55. Retrieved October, 2011 from

https://journals.tubitak.gov.tr/earth/vol16/iss1/3/

Zanchetta, S., Berra, F., Zanchi, A., Bergomi, M., Caridroit, M., Nicorab, A. and Heidarzadeh, G., 2013. The record of the Late Paleozoic active margin of the Palaeotethys in NE Iran: constraints on the Cimmerian orogeny. Gondwana Res, 24(3–4): 1237–1266.

https://doi.org/10.1016/j.gr.2013.02.013

Send comment about this article

Name *

Enter Name.

Email Address *

Enter a valid email address.

Affiliation *

Enter a vaid affiliation.

Comments *

Enter comments (At leaset 10 words)

Security Code *