Jurnal maqolasiOchiq kirish
Qozog‘iston janubi-sharqidagi Jarkent (Sharqiy Ili) havzasining chuqur, kam minerallashgan yuqori bo‘r suvli qatlamlarida geotermal tizim va gidrogeokimyoni belgilovchi geologik omillar
Geological controls on the geothermal system and hydrogeochemistry of the deep low-salinity Upper Cretaceous aquifers in the Zharkent (eastern Ily) Basin, south-eastern Kazakhstan
https://doi.org/10.3389/feart.2023.1212064
Asosiy jihatlar
- Yuqori bo‘r kollektori 2 850 m chuqurlikkacha, qalinligi 30–50 m, o‘tkazuvchanligi sakkiz darsigacha.
- Quduq og‘zida suv harorati 96–102 °C; 5539-quduq (taxminan 2 850 m) 103 °C li suv beradi; boshlang‘ich tabiiy sarf 75,2 l/s gacha.
- Geotermal suvlar minerallashuvi 0,3–0,9 g/l; paleogen suvlari — 22 g/l gacha.
- Geotermik gradient: sharqda 21,1–30,3 °C/km, markazda 25,1–32,9 °C/km, janubda 27,3–53,5 °C/km; Dobin va Shonji yaqinida 40–60 °C/km li anomaliya.
- Barcha namunalar o‘rtachasi: δ²H −99,9 ± 7,61‰, δ¹⁸O −13,7 ± 0,76‰, deyteriy ortiqchaligi 9,52 ± 4,21‰; chuqur geotermal quduqlar (n = 6): δ²H −106,56 ± 2,85‰.
- Mahalliy meteor suvlar chizig‘i: δD = 7,6·δ¹⁸O + 9,4.
Annotatsiya
The Zharkent (eastern Ily) Basin is renowned for its low-salinity natural hot springs and geothermal wells, primarily utilized for recreational purposes. Despite the growing commercial interest, the geothermal system in this area is very poorly documented or understood. Accordingly, we conducted a multi-disciplinary study, focusing on the advanced characterization of waters from productive Cretaceous strata, along with the interpretation of geothermal gradients and reservoir recharge in a geological context. Conventional wisdom asserts that Ily is an intracratonic basin characterized by high geothermal heat in its central part and by geothermal aquifers that are rapidly replenished by meteoric water recharge via porous strata exposed on the basin margin. Our results argue for an alternative and expanded interpretation of these systems. Elevated geothermal gradients (with average of up to 40°C/km in the southern part of the basin and locally possibly up to 55°C/km) are likely associated with crustal thinning owing to the development of a pull-apart basin. Anomalously fresh water (<1 g/L) in the deep (up to 2850 m depth) Upper Cretaceous reservoir is charged laterally, predominantly by snowmelt waters from basin bounding mountains. Recharge includes both mountain-front recharge (MFR), where water infiltrates into outcrops of reservoir rock near the mountain fronts, and mountain-block recharge (MBR), characterized by deep groundwater flow through fractured, predominantly rhyolite basement rocks (as evidenced from their solutes in reservoir waters). The combination of elevated geothermal gradients, low salinity water chemistry, and excellent reservoir properties makes the studied reservoir horizon an attractive target for geothermal development. Our results are applicable to other geothermal systems in strike-slip settings across Central Asia, and potentially worldwide.
Mualliflar annotatsiyasi CC BY 4.0 litsenziyasi asosida keltirilgan. Annotatsiya ingliz tilida berilgan.
Kalit so‘zlar
- geotermal energiya
- Jarkent havzasi
- gidrogeokimyo
- cho‘zilish botig‘i
- yer osti suvlari
- barqaror izotoplar
Sodda qilib aytganda
Qozog‘iston janubi-sharqidagi Jarkent (Sharqiy Ili) havzasi asosan dam olish uchun foydalaniladigan kam minerallashgan issiq buloqlari va geotermal quduqlari bilan mashhur. 1950-yillarda neft qidiruv quduqlari 2 682–2 730 m chuqurlikdagi yuqori bo‘r kollektorlarida issiq suv — quduq og‘zida taxminan 96 °C — ochgan; yaqinda burg‘ilangan, chuqurligi taxminan 2 850 m bo‘lgan 5539-quduq shu intervaldan 103 °C li suv beradi. Mahsuldor qatlam qalinligi 30–50 m, o‘tkazuvchanligi yuqori — sakkiz darsigacha.
Mualliflar harorat, suv kimyosi, stratigrafiya, gravimetriya va struktura ma’lumotlarini qayta ishlab, 2021 va 2022-yillarning may–iyun oylarida quduq va buloqlardan namunalar oldi: 2,5 km dan chuqur to‘rtta geotermal quduq, 600–700 m li beshta geotermal quduq, grunt suvi quduqlari, buloq, iliq artezian qudug‘i va soy. 18 ta quduq ma’lumotlariga ko‘ra, geotermik gradient havzaning sharqida 21,1–30,3 °C/km, markazida 25,1–32,9 °C/km, janubida 27,3–53,5 °C/km; Dobin va Shonji aholi punktlari yaqinida 40–60 °C/km li kuchli anomaliya bor.
Mualliflar fikricha, havza siljima yoriqlar natijasida hosil bo‘lgan cho‘zilish botig‘i (pull-apart), gradientlarning notekisligi esa po‘stning notekis yupqalashuvidan kelib chiqadi. Issiqlik asosan konduktiv yo‘l bilan uzatiladi, ammo ochiq yoriqlar bo‘ylab ko‘tariluvchi suv joy-joyda qo‘shimcha issiqlik berishi mumkin. Yuqori bo‘r suvi chuchuk — 0,3–0,9 g/l, ustidagi paleogen va neogen qatlamlarida esa yer yuzasidan sizib tushadigan suv hisobiga minerallashuv 20 baravargacha yuqori.
Barqaror izotoplar chuqur suvlar asosan qor erishidan to‘yinishini ko‘rsatadi: og‘ir izotoplarga eng kambag‘al suv chuqur geotermal quduqlardan chiqadi. Erigan kremnezem va boshqa ionlar suv kollektorga ham u tog‘ etagida yer yuzasiga chiqqan joylarda, ham tog‘lar ostidagi yoriqli riolit fundament orqali kelishidan dalolat beradi. Mualliflar yuqori gradientlar, chuchuk suv va a’lo kollektorlik xossalari yuqori bo‘r qatlamini jozibador geotermal obyektga aylantiradi, natijalar esa Markaziy Osiyodagi siljima zonalaridagi boshqa geotermal tizimlarga ham tegishli, degan xulosaga keladi.
Rasmlar (2)
Iqtibos namunasi
Ashirgul Kozhagulova, Vadim Yapiyev, Leila Karabayanova, Antoine Dillinger, Vyacheslav Zavaley, Aisulu Kalitova, Emil Bayramov, John Holbrook, Stephen E. Grasby and Milovan Fustic (2023). Geological controls on the geothermal system and hydrogeochemistry of the deep low-salinity Upper Cretaceous aquifers in the Zharkent (eastern Ily) Basin, south-eastern Kazakhstan. Frontiers in Earth Science, vol. 11, 1212064. https://doi.org/10.3389/feart.2023.1212064