Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques,which do not fully provide quantification of uncertainty in the constructed models and fail to ...Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques,which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data.Here,using the Bayesian Obsidian software package,we develop a methodology to fuse lithostratigraphic field observations with aeromagnetic and gravity data to build a 3D model in a small(13.5 km×13.5 km)region of the Gascoyne Province,Western Australia.Our approach is validated by comparing 3D model results to independently-constrained geological maps and cross-sections produced by the Geological Survey of Western Australia.By fusing geological field data with aeromagnetic and gravity surveys,we show that 89%of the modelled region has>95%certainty for a particular geological unit for the given model and data.The boundaries between geological units are characterized by narrow regions with<95%certainty,which are typically 400-1000 m wide at the Earth's surface and 500-2000 m wide at depth.Beyond~4 km depth,the model requires geophysical survey data with longer wavelengths(e.g.,active seismic)to constrain the deeper subsurface.Although Obsidian was originally built for sedimentary basin problems,there is reasonable applicability to deformed terranes such as the Gascoyne Province.Ultimately,modification of the Bayesian engine to incorporate structural data will aid in developing more robust 3D models.Nevertheless,our results show that surface geological observations fused with geophysical survey data can yield reasonable 3D geological models with narrow uncertainty regions at the surface and shallow subsurface,which will be especially valuable for mineral exploration and the development of 3D geological models under cover.展开更多
Constraining the processes associated with the formation of new(juvenile)continental crust from mantle-derived(basaltic)sources is key to understanding the origin and evolution of Earth’s landmasses.Here we present h...Constraining the processes associated with the formation of new(juvenile)continental crust from mantle-derived(basaltic)sources is key to understanding the origin and evolution of Earth’s landmasses.Here we present high-precision measurements of stable isotopes of potassium(K)from Earth’s most voluminous plagiogranites,exposed near El-Shadli in the Eastern Desert of Egypt.These plagiogranites exhibit a wide range of d41K values(–0.31‰±0.06‰to 0.36‰±0.05‰;2 SE,standard error)that are significantly higher(isotopically heavier)than mantle values(–0.42‰±0.08‰).Isotopic(87Sr/86Sr and^(143)Nd/^(144)Nd)and trace element data indicate that the large variation in d41K was inherited from the basaltic source rocks of the El-Shadli plagiogranites,consistent with an origin through partial melting of hydrothermally-altered mid-to-lower oceanic crust.These data demonstrate that K isotopes have the potential to better constrain the source of granitoid rocks and thus the secular evolution of the continental crust.展开更多
基金funded by the Science and Industry Endowment Fund as part of The Distal Footprints of Giant Ore Systems:UNCOVER Australia Project(RP04-063)-Capricorn Distal Footprints。
文摘Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques,which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data.Here,using the Bayesian Obsidian software package,we develop a methodology to fuse lithostratigraphic field observations with aeromagnetic and gravity data to build a 3D model in a small(13.5 km×13.5 km)region of the Gascoyne Province,Western Australia.Our approach is validated by comparing 3D model results to independently-constrained geological maps and cross-sections produced by the Geological Survey of Western Australia.By fusing geological field data with aeromagnetic and gravity surveys,we show that 89%of the modelled region has>95%certainty for a particular geological unit for the given model and data.The boundaries between geological units are characterized by narrow regions with<95%certainty,which are typically 400-1000 m wide at the Earth's surface and 500-2000 m wide at depth.Beyond~4 km depth,the model requires geophysical survey data with longer wavelengths(e.g.,active seismic)to constrain the deeper subsurface.Although Obsidian was originally built for sedimentary basin problems,there is reasonable applicability to deformed terranes such as the Gascoyne Province.Ultimately,modification of the Bayesian engine to incorporate structural data will aid in developing more robust 3D models.Nevertheless,our results show that surface geological observations fused with geophysical survey data can yield reasonable 3D geological models with narrow uncertainty regions at the surface and shallow subsurface,which will be especially valuable for mineral exploration and the development of 3D geological models under cover.
基金the Editorial Advisor Prof.M.Santosh,Associate Editor Dr.S.Glorie,and two anonymous reviewers for their comments.H.G.acknowledges funding from the Khalifa University start-up fund(8474000697/FSU-2024-006)K.W.acknowledges support from the McDonnell Center for the Space Sciences and NASA(Emerging Worlds Program Grant No.#80NSSC21K0379)T.E.J.acknowledges funding from the Australian Government through an Australian Research Council Discovery Project(DP200101104)。
文摘Constraining the processes associated with the formation of new(juvenile)continental crust from mantle-derived(basaltic)sources is key to understanding the origin and evolution of Earth’s landmasses.Here we present high-precision measurements of stable isotopes of potassium(K)from Earth’s most voluminous plagiogranites,exposed near El-Shadli in the Eastern Desert of Egypt.These plagiogranites exhibit a wide range of d41K values(–0.31‰±0.06‰to 0.36‰±0.05‰;2 SE,standard error)that are significantly higher(isotopically heavier)than mantle values(–0.42‰±0.08‰).Isotopic(87Sr/86Sr and^(143)Nd/^(144)Nd)and trace element data indicate that the large variation in d41K was inherited from the basaltic source rocks of the El-Shadli plagiogranites,consistent with an origin through partial melting of hydrothermally-altered mid-to-lower oceanic crust.These data demonstrate that K isotopes have the potential to better constrain the source of granitoid rocks and thus the secular evolution of the continental crust.
