Eburnean Structural Controls on Lithium Pegmatite Emplacement in the Birimian Terrane, Kumasi Basin, Ghana: A Two-Phase Deformation Model and Exploration Framework

Eburnean Structural Controls on Lithium Pegmatite Emplacement in the Birimian Terrane, Kumasi Basin, Ghana: A Two-Phase Deformation Model and Exploration Framework | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Eburnean Structural Controls on Lithium Pegmatite Emplacement in the Birimian Terrane, Kumasi Basin, Ghana: A Two-Phase Deformation Model and Exploration Framework Eric Enzula Bayari, Blestmond Afrifa Brako, Kingsley Kwaah Tandoh, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9657434/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The structural controls on lithium-bearing pegmatite emplacement within the Paleoproterozoic Birimian Supergroup of West Africa remain poorly characterised, impeding systematic exploration targeting in one of the region's most prospective critical mineral terranes. This study presents the first integrated structural investigation of the Atia Pegmatite Field, northeastern Kumasi Basin, Ghana, with the aim of defining the primary deformational controls on pegmatite distribution, orientation, and lithium fertility. Through systematic field mapping of 27 intragranitic pegmatite-aplite veins hosted in biotite granite and granodiorite, combined with quantitative structural analysis and kinematic characterisation of the Apemso and Ofoase pegmatite bodies, two resolvable Eburnean deformation phases are identified. The D 2 phase (NW–SE shortening; σ 1 = N140°) generated the S1 foliation (NE43° − 67°; dip 60° − 63° SE), microfolding, and asymmetric boudinage; pegmatites emplaced during this phase are folded, boudinaged, and barren with respect to lithium mineralisation. The D3 phase (NNW-SSE shortening; σ 1 = N160°), characterised by a 20° clockwise stress rotation, produced semi-ductile to brittle dextral shear zones (N36° - N55°; dip 49° − 88°) and associated Riedel tension gashes that facilitated emplacement of lithium-bearing veins oriented ENE - WSW (031° − 340°) with dips of 30° − 60° SE. Jigsaw-fit vein wall geometry and the absence of metasomatic aureoles support a non-displacement, fracture-dilation emplacement mechanism. These findings establish that lithium prospectivity in the Atia Field is intrinsically linked to Eburnean D 3 deformation history, and that NNW-SSE-trending D 3 shear corridors and biotite-granite roof zones constitute the primary structural exploration targets for lithium in Birimian terranes. Geology Birimian Eburnean orogeny Emplacement Lithium pegmatite Structural controls Kumasi Basin Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9657434","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":637093503,"identity":"bbddad5c-10a2-4a20-996d-ef6d095734a5","order_by":0,"name":"Eric Enzula 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on lithium-bearing pegmatite emplacement within the Paleoproterozoic Birimian Supergroup of West Africa remain poorly characterised, impeding systematic exploration targeting in one of the region's most prospective critical mineral terranes. This study presents the first integrated structural investigation of the Atia Pegmatite Field, northeastern Kumasi Basin, Ghana, with the aim of defining the primary deformational controls on pegmatite distribution, orientation, and lithium fertility. Through systematic field mapping of 27 intragranitic pegmatite-aplite veins hosted in biotite granite and granodiorite, combined with quantitative structural analysis and kinematic characterisation of the Apemso and Ofoase pegmatite bodies, two resolvable Eburnean deformation phases are identified. The D\u003csub\u003e2\u003c/sub\u003e phase (NW\u0026ndash;SE shortening; σ\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;N140\u0026deg;) generated the S1 foliation (NE43\u0026deg; \u0026minus;\u0026thinsp;67\u0026deg;; dip 60\u0026deg; \u0026minus;\u0026thinsp;63\u0026deg; SE), microfolding, and asymmetric boudinage; pegmatites emplaced during this phase are folded, boudinaged, and barren with respect to lithium mineralisation. The D3 phase (NNW-SSE shortening; σ\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;N160\u0026deg;), characterised by a 20\u0026deg; clockwise stress rotation, produced semi-ductile to brittle dextral shear zones (N36\u0026deg; - N55\u0026deg;; dip 49\u0026deg; \u0026minus;\u0026thinsp;88\u0026deg;) and associated Riedel tension gashes that facilitated emplacement of lithium-bearing veins oriented ENE - WSW (031\u0026deg; \u0026minus;\u0026thinsp;340\u0026deg;) with dips of 30\u0026deg; \u0026minus;\u0026thinsp;60\u0026deg; SE. Jigsaw-fit vein wall geometry and the absence of metasomatic aureoles support a non-displacement, fracture-dilation emplacement mechanism. These findings establish that lithium prospectivity in the Atia Field is intrinsically linked to Eburnean D\u003csub\u003e3\u003c/sub\u003e deformation history, and that NNW-SSE-trending D\u003csub\u003e3\u003c/sub\u003e shear corridors and biotite-granite roof zones constitute the primary structural exploration targets for lithium in Birimian terranes.\u003c/p\u003e","manuscriptTitle":"Eburnean Structural Controls on Lithium Pegmatite Emplacement in the Birimian Terrane, Kumasi Basin, Ghana: A Two-Phase Deformation Model and Exploration Framework","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-12 16:07:40","doi":"10.21203/rs.3.rs-9657434/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0c5d5eff-eb47-4b2f-9ab5-d1d75220c692","owner":[],"postedDate":"May 12th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":67815630,"name":"Geology"}],"tags":[],"updatedAt":"2026-05-12T16:07:40+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-12 16:07:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9657434","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9657434","identity":"rs-9657434","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}