بازسازي مرز برف‌هاي كواترنري پاياني در حوضه‌ي چشمه كيله

In this study, the Cheshmeh Kileh drainage basin in Tonekabon County was investigated. This basin comprises sub basins of the Do Hezar watershed (including the two major glaciated sites of Sialan an‎d Khashchal) an‎d the Se Hezar watershed, which hosts major glacier systems such as Alam Kuh, Takht e Soleyman, Haft Khan, an‎d others. In the first phase, glacial geomorphological indicators—such as cirques, glacial valleys, various types of moraines, an‎d terminal drift deposits located at valley mouths—were systematically identified. Subsequently, glaciated sub basins were delineated an‎d selec‎ted for reconstructing Quaternary snowline elevations. In this research, a comprehensive set of digital elevation–based datasets was prepared, including DEMs, hillshade models, sub basin boundaries, cirque layers, moraine an‎d terminal drift layers, drainage networks, cirque an‎d glacial lan‎dform polylines, slope an‎d aspect maps, summit locations, stream ordering, elevation classes, geological units, an‎d fault layers. These thematic glacial an‎d geomorphological layers were integrated within a GIS environment, an‎d detailed geomorphological maps were produced for the selec‎ted sub basins. Using the Höfer an‎d Louis methods, along with the mean cirque floor elevation approach, former equilibrium line altitudes (ELAs) were calculated. By integrating geomorphological evidence with present day climatic data, past morphoclimatic conditions were reconstructed. The main results are summarized as follows: Based on the identification of four glaciated sub basins, the results indicate that Quaternary glaciation was more intense in the southeastern part of the Cheshmeh Kileh basin than in its western sector. A total of 30 glacial cirques were identified, with an overall mean cirque floor elevation of 3597 m a.s.l. In the southeastern sector, the mean cirque floor elevations of the major glaciated sub basins of Haft Khan an‎d Garmarud are 4315 m an‎d 3334 m, respectively, reflecting the presence of a currently active perennial glacier in the Haft Khan sub basin. In contrast, the mean cirque floor elevations in the western glaciated sub basins of Haloukoleh an‎d Nesharud were calculated as 3605 m an‎d 3496 m, respectively. Equilibrium line altitudes estimated using the Höfer an‎d Louis methods yield values of 3558 m an‎d 3825 m for Haft Khan, 3167 m an‎d 3756 m for Garmarud, 2928 m an‎d 2937 m for Haloukoleh, an‎d 2873 m an‎d 2988 m for Nesharud. The lowest altitudes of glacier termini were estimated at 2800 m in the Haft Khan sub basin, 3000 m in Garmarud, an‎d 2250 m in both the Haloukoleh an‎d Nesharud sub basins.

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