01 ivanov jv-inkai_llp_iaea_2012
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The document summarizes research on the regional geology surrounding the Inkai uranium deposit in Kazakhstan. It discusses the tectonic evolution of Central Asia that led to giant uranium deposits forming in the Chu-Sarysu basin. Key factors included the rise of the Tien Shan mountains which drove an infiltration regime and groundwater flow towards the basin. The juxtaposition of the active Tien Shan and the quiescent Chu-Sarysu basin was propitious for concentrating uranium deposits. While much is known, questions remain about sediment provenance and the source of uranium that could be answered with additional study.
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01 ivanov jv-inkai_llp_iaea_2012
- 1. Inkai: the elephant and his habitat Regional geology, MZ-CZ tectonic evolution of Central Asia and the origin of giant uranium deposits in the Chu-Sarysu basin. S. Ivanov, A. Shurilov, V. Kondrashov, A. Glushkov IAEA technical meeting, Vienna, 2012
- 2. Acknowledgments JV Inkai LLP Anatoliy Gots Aleksei Matunov (now Karatau LLP) Volkovgeology (Kazatomprom) Vladimir Chernyakov Viktor Karelin Igor Kashafutdinov Sergey Shepelev Igor Shishkov Alexander Vershkov Cameco Corporation Dan Brisbin Adrienne Hanly (now IAEA) Dan Jiricka Steve Lunsford (Cameco Resources Inc) Alain Mainville Scott McHardy Vlad Sopuck
- 3. Agenda Inkai geology overview Regional settings Paleogeography, tectonosedimentary settings The rise of the Tien-Shan Tien-Shan & Chu-Sarysu: the propitious juxtaposition Comparison to other basins and provinces Conclusions Important,if not unique, features of Chu-Sarysu What else important we do not, but want to know?
- 4. Inkai and its immediate neighbors k My nkudu Block 3 (exploration) INKAI Sholakespe South Inkai Block 1 (mining) Block 2 (mining) 10 KM Budennovskoe
- 5. Inkai: Resources and Reserves (in situ) Source: Cameco, NI-43-101 Technical report, March 2010 Block 3 (exploration) (Still ongoing) Block 1 (mining) Block 2 (mining) Resource reported 10 KM
- 6. Inkai: hydrostratigraphic cross-section A B Aquifers ards quit Intymak A Uyuk Uvanas A s Zhalpak fer Inkuduk Aqui 100 m Mynkuduk 2500 m Campanian- Quarternary Maastrichtian B Turonian-Santonian Oligocene- Lower Turonian Miocene 10 KM Paleocene Permian shales
- 7. Geological X-section 1 KM 40 m 200 m 10 KM
- 9. 88 Ma Turonian (Mynkuduk level): lacusrine-alluvial plains 90 Ma InkaiMynkuduk Mynkuduk Inkai Budennovskoe Budennovskoe Harasan Adapted from Fedorenko, O.A, 2002
- 10. 70 Ma Maastrichtian (Inkuduk level) moderate transgression, alluvial plain 70 Ma Adapted from Fedorenko, O.A, 2002
- 11. 50 Ma Eocene (Intymak level): transgression 50 Ma Tortkuduk Moinkum Kanzhugan Adapted from Fedorenko, O.A, 2002
- 12. The Eucla basin: a distant young relative? Tectonosedimentologically Epeirogenic subsidence Terrestrial and marine environments Sea trans-regressions Fluvial systems Few sediment transport vectors dominate A way more arid? (at least now) No Tien-Shan mountains nearby! …. Sorry… 300 KM Source: B. Hou et al., 2008
- 13. 30 Ma Oligocene: India-Asia collision. Infiltration regime sets in 35 Ma Adapted from Fedorenko, O.A, 2002
- 14. 2 Ma Pliocene: Infiltration continues 0 Ma Adapted From Fedorenko, O.A, 2002
- 15. Paleogeography, sedimentology Late Cretaceous – Late Eocene Epeirogenic subsidence Sea re-transgression cycles Chu-Sarysu – mostly terrestrial settings Fluvial-lacustrine plains Megachannel fluvial systems Syrdaria – mostly marine settings Marine,transitional, coastal environment Beach sands Oligocene – present Foreland (hinterland?) basin to the Tian-Shan foldbelt
- 16. The rise of Tien-Shan and its role In response to India-Asia collision 30 Ma: Southern Tian-Shan uplifting southward thrusts (onto Tarim basin) Infiltrational regime set in Chu-Sarysu NW direction of groundwater flow Atmospheric circulation changes – arid climate 11 Ma: Northern Tian-Shan uplifting northward thrusts, southward backthrusts Sustained hydraulic connectivity
- 19. The Tien-Shan – Chu-Sarysu junction B A B backthrusts A Abdrakmatov, 2001. Shortening in Central Tien-Shan.
- 20. The Tarim basin A Foreland basin to the South Tien- Shan Tectonic activity propagated into the basin B Precludes hydraulic connectivity B A Thrusting, folding Source : Wikipedia
- 21. Laramide vs Chu-Sarysu Intermontane vs epeirogenic basins Paleodrainage vectors Multiplicity & intermittence Protracted dominance of the few Tectonic activity High, proximal Low, distal Infiltration & sedimentation Consequent vs subsequent Redox front propagation Tens of km Hundreds of km Kyzylkum is similar!
- 22. Laramide basins Previous slide Paleogeography Paleotectonics tectonics Source: Dickinson,1988. Paleogeographic and paleotectonic setting of Laramide sedimentary basins in the central Rocky Mountain region.
- 24. Conclusions 1 The Chu-Sarysu is different, (if not unique) Hosting strata deposited on continental margins Epeirogenic subsidence Fluvial – lacustrine coastal plains Consistent and compositionally favorable hydrostratigraphy Tien-Shan rise not consequent to the epeirogeny Propitious (if not rare) juxtaposition Quiescent (but not completely dormant) Chu-Sarysu Active (very) Tien-Shan Foreland or hinterland? The NW-ward groundwater flow dominates The mineralizing system still active
- 25. Conclusions 2 (questions, really) Sediment provenance, basin architecture well constrained? New AFT data now available Abundant new information from recent drilling Nailing down the elusive uranium source The Tien-Shan? Other uplifts? The aquifers? Is it important? Ingress of reducants from the PZ substrate? Chu-Sarysu is an oil-gas bearing province Post-sedimentary fault reactivation present Are additional reductants really necessary? Last original studies? The 1980s…. Do we want to know more?
- 26. THE END Questions? Photo by Scott McHardy, 2009
Editor's Notes
- Ladies and gentlemen! It is my honor to speak before this audience, which collectively represents the cutting edge knowledge around the globe of the sandstone type of uranium deposits. I also consider to be the greatest honor to work on some of the finest and largest deposits in its class. Inkai certainly belongs to the class of elephants as far as the size and economics go. However, we think that the genesis of such giants cannot be understood without firm understanding the regional geology, MZ-CZ evolution of the region. The region in question, is listed as number one in the world both in the terms of resource size and quality, and is dwelled by a number of rather large anumals. Therefore, the talk will aim at highlighting the significance of some of the features of the habitat where these animals evolved, that is, the geological features of the region that we believe are important ontributors to the uniqueness of the Chu-Sarysu uraniferous province.
- Before I proceed any further I’d like to thank and acknowledge the following individuals whose vast knowledge and willingness to discuss and debate the endless intricacies of the sandstone uranium deposit geology made it possible for me to stand on the shoulders of the giants and offer you our humble thoughts. The following organizations are also acknowledged: JV Inkai and its shareholders. Thanking IAEA and the organizers of this conference goes without saying.
- We will briefly overview the geology of Inkai before we get into the discussion of the topic which we believe has the key to understanding it: its regional context. For sandstone deposit understanding begins with the paleogeography and tectonosedimentary settings of the basin. The tectonic events that lead to establishing a mineralizing system due to infiltration of oxygenated and uraniferous fluids into the basin follow. While all sandstone uranium provinces owe its existence to these two basic features, we will take a closer look at the juxtaposition of the Chu-Sarysu and
- Inkai and its immediate neighbors are shown on the right hand side, which are: Mynkuduk deposit to the NE and south Inkai and Budennovskoe deposits in the S and SW. The blue color indicates the redox fronts and associated mineralization in the Mynkuduk horizon, the lowermost in Chu-Sarysu, while blue color indicates the redox fronts and mineralizstion in the Inkuduk formation, overlaying Mynkuduk formation. Please note the ubiquitous northwestward orientation of the crests in the redox fronts sinusoids and the relationship of the propagation among different formations. Usually Inkuduk redox fronts are propagated more than Mynkuduk, albeit there is a plenty of stacked horizon situations, the northern part of Inkai Block 2 be a typical example of it. The underexplored Sholakespe occurrence occur in the Zhalpak horizon that overlays Inkuduk. We all are familiar with the geometric, or rather geographic size of the sanstone uranium deposits, please note the the map of Vienna given for the scale, besides the scale bars. The lefthand insert shows the map of Inkai where mineralization is divided into up to four horizons, which are, as shown on the legend, are Lower Mynkuduk (pink), Upper Mynkuduk (orange), Lower Inkuduk (green) , and Middle Upper Inkuduk (blue). JV Inkai is mining Block 1 and Block 2, while at Block 3 exploration is still ongoing.
- This slides shows the resources and reserves as reported by Cameco Corporation in its NI-43-101 report filed in March 2010. The report, by the way is a recommended reading for those intersted in the explaration, geology and mining at Inkai. It shows resources and reserves for Blocks 1 and 2 only. Both blocks total to 412 mln lbs U3O8 or just a litte less than 160 thousand tonnes of uranium metal. Please also note that the in-situ resources are shown, without accounting for mining-metallurgical loss, which is roughly 18 percent. With such a resource base on Block 1 and 2 only Inkai is firmly placed into the weight class of elephants.
- Now let’s take a look at the NW-SE hydrostratigraphic cross-section A-B. Please note the 25-fold vertical exaggeration. The column consists of several formations that range in age from lower Turonian to Quarternary. The aquifers that host mineralization at Inkai are confined to the Mynkuduk and Inkuduk formations. These aquifers contain only small and discontinuous intraformational lenses of aquitards. Effectively, the entire column upto the bottom of the Uyuk formation can be consisdered as aquifers. Thus, at Inkai, the accumulated thickness of uraniferous part aquifers reaches 100-150 m. Note the NW orientation of the anterior crests and the capricious shape of the redox front and mineralization zones. Also note that the aquifers are capped by a 100 m thick layer of clay (the Intymak and in this case , Uyuk hprizons. Also note the effect which the PZ basement relief exerts onto the sedimentary cover. There are examples of both pre- syn- and post-sedimentary movement.
- This cross-section shows the anatomy of the elephant in grater details (please note the five-fold exageration of the vertical scale. The x-section goes through the location with stacked ore. Here, the mineralization the Mynkuduk is relatively well confined hydraulically not only from below, but also from the top by this rather thick layer of clay. The mineralization in Lower inkuduk occurs in the layer 40 to 60 m thick, where mineralization is only sporadically confined from below, and pretty much unconfined from above. The redox fronts and mineralization in the upper Inkukud propagated 1.5 km farther to the NW in this case and is Inkuduk is oxidized.
- As mentioned before, Inkai is one of the largest deposits, but it represent only a segment in one a a few the continuous trends of redox fronts and associated mineralization. The frame of the previous slide is given here for reference. This map shows the place of Inkai in the regional context. Different color represent redox fronts that occur in different horizons that are given in the stratigraphical order in the legend. One can distinguish between Cretaceous and Tertiary trends. The redox fronts in the former are propagated most and sitiated some 120 km farther to the NW. Please, again, note the crests are oriented to the NW, although the redox front geometry is affected by
- Here is a palinspastic map for 88 Ma time slice. The present-day hydrography, basins, mountains and the location of uranium deposits are given for reference. The lowemost uraniferous Mynkuduk horizon was formed during the Turonian of Late Cretaceous. The Chu-Sarysu basin was located to the SW of the Paleozoic Central Kazakhstan in passive continental margins settings comprising fluvial plains, the rivers flowing to the Tethys sea in the SW. Please note, the change in the sedimentation environment going from NE to SW from the erosional plain of Central Kazakhstan to alluvial plain of Chusarysu to transitional zone in Syrdaria basin and eventually to the marine environment of Amu-Daria basin. There was no vast high mountains back then, most of formerly formed mountains during the Late Paleozoic orogeny had been eroded by 88 Ma. In the upper right corner is a worldwide reconstruction, and a central Asia reconstruction is n the left corner. Windows roughly show where we are looking at. India just relatively recently departed from Antarctica and was starting its way to the north. This is what I would call a Chekhov’s gun. Which is a literary technique when seemingly irrelevant detail is introduced early in the play, the true significance of which is revealed later on. Such as if someone hangs up a gun on the wall in Act 1, it must fire in Act 3. Of course I do not expect any such dramatic effect in this case since we all know where India is now. It is merely to highlight the circumstance that the tectonic regime of epeirogenic subsidnce during this this stage did not conceive the eventual arrival of India as a consequence of its evolution.
- During Maastrichtian the sea transgressed a bit, and the Chu-Sarysu coalesced with the Syr-Darya basin which represented changes in the sedimentary environment from allivial to transitional to marine and marine.
- The late Eocene was one of the warmest periods in MZ-CZ. It resulted in a global rise of the sea level, so, the entire coastal plain was flooded. This provided the ultimate and regional confinemet for the previously formed aquifers.
- At about 30 Ma India-Asia collision started. It gave another rise to the Tien-Shan, and the infiltrational regime set in and was well established by Miocene.
- By Pliocene the rolls propagated away from the Tien-Shan many tens to a few hundreds of km in Chu-Sarysu. Tien-Shan is now a large recharge area for the huge artesian basins of Chu-Sarysu and Syrdaria.