163 results
Search Results
2. Discussion of 'Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf'1.
- Author
-
Waldron, John W.F., White, Chris E., and Murphy, Brendan
- Subjects
GEOCHEMISTRY ,ORDOVICIAN Period ,SEDIMENTARY rocks ,ATMOSPHERIC models ,GROUPS (Stratigraphy) ,WATER depth - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
3. Geochemistry, zircon geochronology, and isotopic systematics of the Zhanbuzhale granites in the East Kunlun, Qinghai Province, northwestern China: implications for the tectonic setting.
- Author
-
Li, Hao-Ran, Qian, Ye, Sun, Feng-Yue, and Li, Liang
- Subjects
GEOCHEMISTRY ,ZIRCON ,GRANITE ,FELDSPAR ,GRANODIORITE ,GEOLOGICAL time scales ,AMALGAMATION - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
4. Introduction to the Special issue of the Canadian Journal of Earth Sciences, "Magmatic and metallogenic processes associated with large igneous provinces".
- Author
-
Williamson, Marie-Claude and Saumur, Benoit M.
- Subjects
IGNEOUS provinces ,EARTH sciences ,MINES & mineral resources ,IGNEOUS rocks ,GEOCHEMISTRY ,PETROLOGY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
5. U-Pb geochronology and trace element composition of zircon from the Horseshoe Lake greenstone belt, Superior Province, Canada: implications for the tectonic and metamorphic history.
- Author
-
Kelly, C.J., Schneider, D.A., Lajoie, M.-È., Jackson, S.E., and McFarlane, C.R.
- Subjects
ZIRCON ,TRACE elements ,RARE earth metals ,GEOCHEMISTRY ,METAMORPHISM (Geology) ,SEDIMENTARY rocks - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
6. Analysis of the charging process of the lacustrine tight oil reservoir in the Triassic Chang 6 Member in the southwest Ordos Basin, China.
- Author
-
Xu, Zhengjian, Liu, Luofu, Wang, Tieguan, Wu, Kangjun, Dou, Wenchao, and Song, Xingpei
- Subjects
LAKE hydrology ,PETROLEUM reservoirs ,PALEOGENE ,GEOCHEMISTRY ,CRETACEOUS Period - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
7. Geochemistry, geochronology, and radiogenic isotopes of the Balmer and Confederation assemblages of the Laird Lake Area, Red Lake greenstone belt, Canada: implications for Archean tectonic evolution.
- Author
-
Gélinas, Brigitte R., Hollings, Pete, and Friedman, Richard
- Subjects
GREENSTONE belts ,GEOCHEMISTRY ,GEOLOGICAL time scales ,FELSIC rocks ,MAFIC rocks ,BRECCIA ,VOLCANISM - Abstract
The Laird Lake property, southwest Red Lake greenstone belt, straddles the contact between the Balmer (2.99–2.96 Ga) and the Confederation (2.74–2.73 Ga) assemblages. The property is 10 km along strike from the Madsen and Starrat–Olsen Au mines that are hosted near the contact. The Balmer assemblage consists of fine-grained, aphyric, locally pillowed mafic volcanic rocks, ultramafic intrusive and volcanic rocks with flow breccia textures hosting local spinifex-bearing clasts, and banded-iron formations. In contrast, the Confederation assemblage comprises porphyritic mafic volcanic rocks intercalated with intermediate to felsic volcanic rocks that include crystal lapilli tuffs, crystal tuffs, and tuffs. The Balmer assemblage is composed of tholeiitic mafic volcanic rocks with minor Al-undepleted komatiites, whereas the Confederation assemblage is calc–alkalic. Neodymium isotopes, in conjunction with trace element geochemistry, suggests that parts of the Balmer assemblage were weakly contaminated by an older intermediate basement. Both arc and back-arc volcanism occurs in the Confederation assemblage, with the arc rocks showing a stronger crustal component than the back-arc rocks. A maximum U–Pb age of 2741 ± 19 Ma for a crystal tuff and an age of 2737.68 ± 0.79 Ma for a diorite are consistent with a Confederation assemblage affinity for the intermediate calc–alkaline rocks south of the Au-bearing horizon. The Balmer assemblage represents an oceanic plateau formed by plume magmatism on the margins of the North Caribou Terrane, whereas the Confederation assemblage at Laird Lake formed in an oceanic arc setting where both arc and back-arc volcanism occurred simultaneously. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Petrology and lithogeochemistry of Paleozoic alkalic magmatism in the Selwyn Basin, Yukon, Canada.
- Author
-
Scanlan, Emma J., Leybourne, Matthew I., Layton-Matthews, Daniel, Van Wagoner, Nancy, Paradis, Suzanne, Piercey, Steve, and Crowley, James L.
- Subjects
PETROLOGY ,RARE earth metals ,VOLCANIC ash, tuff, etc. ,PALEOZOIC Era ,GEOCHEMISTRY ,MAGMATISM ,DIKES (Geology) - Abstract
Alkalic magmatism occurred in the Selwyn Basin, Yukon, Canada throughout the Paleozoic, concurrent with extension during passive margin sedimentation. To examine magmatism associated with this extension, geochemical data were obtained from several locations in the Selwyn Basin (MacMillan Pass, Anvil District, Keno Hill, and the Misty Creek Embayment). Volcanic rocks from the Anvil District and the Misty Creek Embayment are dominated by alkalic basalts with light rare earth element (LREE)-enriched geochemical signatures, whereas metavolcanic and dike samples from Keno Hill comprise subalkaline basalts with enriched mid-ocean ridge basalt (E-MORB) signatures. The Early Ordovician Menzie Creek volcanic rocks of the Anvil District display trace element geochemical signatures intermediate between ocean island basalt (OIB) and E-MORB, whereas the Middle–Late Ordovician volcanic rocks from the Misty Creek Embayment have OIB signatures. Differences in the trace element geochemistry of the sample suites are attributed to the degree of partial melting. The Menzie Creek volcanic rocks formed from large volume melts of enriched mantle that diluted incompatible element signatures in the Early Ordovician. Late Ordovician magmatism produced the Misty Creek Embayment samples, where restricted melt volumes of an enriched mantle source resulted in the most enriched samples geochemically. The Keno Hill samples represent the shallowest melting of the analysed samples and may have resulted from melting of heterogenous subcontinental lithospheric mantle. Magmatic zircons from a Keno Hill metavolcanic sample analysed by chemical abrasion thermal ionization mass spectrometry resulted in a primary deposition age of c. 296 ± 0.36 Ma (Early Permian), during a period with little magmatism in the Selwyn Basin and representing a previously unknown unit in the area. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. LA-ICP-MS zircon U–Pb ages, geochemistry, and genesis of Paleozoic granites from Biezhentao Mountain, Western Tianshan, Xinjiang.
- Author
-
Li, Xiang, Xia, Fang, Gao, Ling-Ling, Chen, Chuan, Du, Xiao-Fei, and Li, Shun-Da
- Subjects
GEOCHEMISTRY ,OROGENIC belts ,PALEOZOIC Era ,GRANITE ,LASER ablation inductively coupled plasma mass spectrometry ,ZIRCON ,DIORITE ,ACCRETIONARY wedges (Geology) - Abstract
The geologic history of the Western Tianshan region is important for understanding the evolution of the Central Asian Orogenic Belt and accretionary orogenesis. Paleozoic and Mesozoic igneous rocks are present along the northern margin of the Yili Block; however, studies of Paleozoic subduction and collisional events have been relatively limited. Published geochronologies of Middle Devonian magmatic rocks in this region are also lacking. Therefore, this study analyzed the zircon U–Pb ages and major and trace elemental compositions of three granite types collected from Biezhentao Mountain (Wenquan County, Western Tianshan). The medium-grained diorite (384.1 ± 3.6 Ma) and diorite–porphyrite (382 ± 3.2 Ma) are silica-rich, weakly peraluminous, alkali-rich, enriched in large-ion lithophile elements, depleted in high field strength elements, and belong to the calc–alkaline series, with A-type granite characteristics. The monzogranite (423.3 ± 9.4 Ma) exhibits A-type granite characteristics and belongs to the peraluminous calc–alkaline series. The findings suggest that the granitoids recorded two stages of tectonomagmatism during the Middle Devonian–Late Silurian. The Middle Devonian medium-grained diorite and diorite–porphyrite formed in a back-arc extensional setting, whereas the Late Silurian monzogranite formed in an active continental margin setting during the subduction of the North Tianshan Ocean. These results provide insights into the tectonic and magmatic processes that occurred during the evolution of the Western Tianshan region and the formation and evolution of the Central Asian Orogenic Belt. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Basaltic to andesitic volcaniclastic rocks in the Blake River Group, Abitibi Greenstone Belt: 2. Origin, geochemistry, and geochronology12.
- Author
-
Ross, P.-S., McNicoll, V., Goutier, J., Mercier-Langevin, P., Dubé, B., and Polat, Ali
- Subjects
BASALT ,VOLCANIC ash, tuff, etc. ,GEOCHEMISTRY ,GEOLOGICAL time scales ,CALDERAS ,SUBMARINE volcanoes - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
11. Geochemistry and tectonic significance of alkalic mafic magmatism in the Yukon-Tanana terrane, Finlayson Lake region, Yukon.
- Author
-
Piercey, Stephen J, Mortensen, James K, Murphy, Donald C, Paradis, Suzanne, and Creaser, Robert A
- Subjects
GEOCHEMISTRY ,PLATE tectonics ,MAGMATISM ,ALKALIC igneous rocks ,EARTH sciences - Abstract
This paper provides an integrated field and geochemical study of weakly alkalic, ~360 Ma mafic rocks from the Yukon–Tanana terrane in the Finlayson Lake region, southeastern Yukon. These mafic rocks occur as dykes and sills that crosscut older felsic metavolcanic rocks and metasedimentary rocks (Kudz Ze Kayah unit) or as flows interlayered with carbonaceous metasedimentary rocks. The mafic rocks have signatures similar to those of ocean-island basalts, moderate TiO[sub 2] and P[sub 2] O[sub 5] contents, elevated high field strength element and light rare earth element contents, and ℇNd[sub 350] = +1.1. A subset of the dykes (group 4b) has similar geochemical characteristics but with higher Th/Nb and lower Nb/U ratios, higher Zr and light rare earth element contents, and ℇNd[sub 350] = –2.8. The geochemical and isotopic attributes of these rocks are consistent with formation from either lithospheric or asthenospheric sources during decompression melting of the mantle, with some rocks exhibiting evidence for crustal contamination (group 4b). The alkalic basalts are interpreted to represent ~360 Ma ensialic back-arc rifting and basin generation. It is envisioned that east-dipping subduction, represented by slightly older magmatic suites (Fire Lake unit), was disrupted by subduction hinge roll-back, westward migration of arc magmatism, and the onset of back-arc extension. Decompression melting of the mantle associated with back-arc generation resulted in mantle melting and the formation of the alkalic basalts. The spatial association of this mafic magmatism with crustally derived felsic volcanic rocks and contained volcanogenic massive sulphide mineralization suggests that the associated deposits (Kudz Ze Kayah, GP4F) formed within an ensialic back-arc environment.Cet article présente une étude intégrée de données de terrain et de géochimie de roches mafiques, ~360 Ma, faiblement alcalines, du terrane Yukon–Tanana dans la région du lac Finlayson, dans le sud-est du Yukon. Ces roches mafiques se présentent sous forme de dykes et de filons-couches, qui recoupent des roches métavolcaniques et des roches métasédimentaires (unité Kudz Ze Kayah) plus âgées, ou sous forme de coulées interstratifiées avec des roches métasédimentaires carbonées. Les roches mafiques ont des signatures semblables à celles des basaltes d'îles océaniques, des teneurs modérées en TiO[sub 2] et P[sub 2] O[sub 5] , de hautes teneurs en éléments à champ électrostatique élevé et en éléments de terres rares légers, ainsi qu'un ℇNd[sub 350] = +1,1. Un sous-ensemble des dykes, (groupe 4b), a des caractéristiques géochimiques similaires mais avec un rapport Th/Nb plus élevé, un rapport Nb/U plus faible et une plus haute teneur en Zr et en éléments de terres rares légers, ainsi qu'une valeur de ℇNd[sub 350] = –2,8. Les caractéristiques géochimiques et isotopiques de ces roches concordent avec une formation de source lithosphérique ou asthénosphérique durant la fusion de décompression du manteau, alors que quelques roches montrent des évidences d'une contamination crustale (groupe 4b). Les basaltes alcalins représenteraient l'extension d'arrière-arc ensialique et la génération de bassins, ~360 Ma. On croit que la subduction à pendage vers l'est, représentée par des suites magmatiques légèrement plus âgées (unité Fire Lake), a été perturbée par le repositionnement de la charnière de subduction, la migration vers l'ouest du magmatisme d'arc et le début d'une extension d'arrière-arc. La fusion de décompression du manteau, associée à la génération d'arrière-arc, a conduit à la fusion du manteau et à la formation des basaltes alcalins. L'association spatiale de ce magmatisme mafique et des roches felsiques volcaniques, dérivées de la croûte, et la minéralisation de sulfures massifs volcanogènes qu'on y retrouve portent à croire que les dépôts associés (Kudz Ze Kayah, GP4F) se sont formés dans un environnement d'arrière-arc ensialique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
12. Tectonic setting and provenance analysis of the Yaojia Formation in the northeastern Songliao Basin, NE China: constraints from sandstone geochemistry, Hf isotopes, and zircon U–Pb chronology.
- Author
-
Li, Yan, Yan, Zhao-Bin, Cai, Jianfang, Nie, Feng-Jun, Li, Wenqing, Wang, Dongxu, Zhang, Yao, and Liu, Xiaohui
- Subjects
LASER ablation inductively coupled plasma mass spectrometry ,GEOCHEMISTRY ,ZIRCON ,SANDSTONE ,ISOTOPES ,CLASTIC rocks ,RARE earth metals ,URANIUM - Abstract
The Songliao Basin is rich in uranium ores, and the Yaojia Formation, which is dominated by gray fine-grained sandstones, contains the main ore-bearing stratum. Rocks in the formation contain high SiO
2 , Al2 O3 , and total alkali, with enrichment in Rb, Th, U, K, and light rare earth elements but are depleted in high field strength elements, similar to upper crustal rocks. U–Pb dating of zircon grains from sandstones in the formation yielded four groups of ages, including 99–182, 202–245, 284–365, and 1800–1900 Ma. These ages combined with the Hf isotope composition, geochemical characteristics, and regional history suggest that the Yaojia Formation rocks are associated with passive and active continental margin settings. These clastic rocks originate principally from felsic rocks in the Zhangguangcailing–Xiao Xing'anling area, and these were deposited in oxic freshwater environments. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
13. U–Pb zircon geochronology and geochemistry of the Jurassic magmatic rocks from the region of Cananea and Nacozari, northeastern Sonora, Mexico: timing and composition of the southernmost edge of the Jurassic continental arc.
- Author
-
Valencia-Moreno, Martín, González-León, Carlos M., Solari, Luigi, Rascón-Heimpel, Mario Arturo, González-Becuar, Elizard, Lozano-Santacruz, Rufino, and Pérez-Arvizu, Ofelia
- Subjects
GEOLOGICAL time scales ,GEOCHEMISTRY ,IGNEOUS rocks ,VOLCANIC ash, tuff, etc. ,ZIRCON ,IGNEOUS intrusions ,MAGMATISM - Abstract
Igneous rocks of the Jurassic continental arc of southwest North American Cordillera crop out in the region between Cananea and Nacozari, in northeastern Sonora, Mexico. Contemporaneous igneous rocks occur farther south in the Nazas rift province; however, their tectonic affinity is debated between the southern extension of the Cordilleran arc and an origin associated with decompressive mantle melting during the Pangea breakup. We consider that the studied rocks represent the southernmost expression of the Jurassic continental arc. Four magmatic units are distinguished based on geology, U–Pb zircon geochronology, and geochemical composition. They comprise the Buenos Aires granite dated at 183.8 ± 1.1 Ma, the Mababi granite with ages of 175.5 ± 1.8, 173.5 ± 1.8, and 171.7 ± 1.0 Ma, the Elenita Formation volcanic rocks dated at 169.7 ± 1.7 Ma, and the Cerro Blanco granite dated at 162.3 ± 2.4 Ma. The studied samples correspond to highly differentiated rocks with high-silica contents (69–76 wt.%), low Mg# values (mostly <45), and alkali–calcic and peraluminous compositions suggesting crustal contamination. LREE-enriched normalized slopes with negative Eu anomalies and multielement plots characterized by well-developed negative anomalies of Nb–Ta, P, and Ti provide an unequivocal signal of the continental arc nature. In contrast to the Nazas province, where the Jurassic magmatism consists of discreet volcaniclastic sequences deposited in extensional basins with no evidence of plutonic rocks, the Jurassic continental arc of Arizona and northern Sonora forms a regionally coherent geological feature characterized by large exposures of volcanic and plutonic rocks. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. Fluid evolution and ore genesis of Huaduoshan Cu–Mo prospect, Duobaoshan ore field, northeastern China: evidence from fluid inclusions, H–O–S–Pb isotopes, geochronology, and geochemistry.
- Author
-
Li, Hao-ming, Wang, Ke-yong, Geng, Jian-zhen, Tang, Wen-hao, Sun, Qing-fei, and Wang, Xue
- Subjects
GEOCHEMISTRY ,ZIRCON ,ORE genesis (Mineralogy) ,GEOLOGICAL time scales ,FLUID inclusions ,ORES ,ISOTOPES ,PROSPECTING - Abstract
The Huaduoshan Cu–Mo prospect is in the Duobaoshan orefield, northeast China. The Cu–Mo mineralization occurs in the granodiorites as veinlet-disseminated. The ore-forming process can be divided into four mineralization stages: (I) quartz–pyrite–magnetite; (II) quartz–pyrite–chalcopyrite ± molybdenite; (III) quartz–pyrite–molybdenite–chalcopyrite–sphalerite; and (IV) quartz–calcite–minor pyrite. Liquid-rich two-phase aqueous (L-type), vapour-rich aqueous (V-type) and daughter-minerals three-phase (S-type) fluid inclusions (FIs) were identified at Huaduoshan. The last two types of FIs are absent in stages III and IV. The homogenization temperatures of FIs from stages I to IV are 375–438, 335–378, 283–335, and 223–267 ℃, with corresponding salinities of 2.4–50.4, 2.1–44.9, 2.7–10.1, and 1.7–7.3 wt. % NaCl eqv., respectively. The H–O isotope data of quartz in stages I (δ
18 OH2O = 6.1–8.0‰, δDH2O = −102.4–−94.6‰) show a magmatic origin of ore-forming fluid; the decreasing δ18 OH2O (−6.8–3.2‰) and δDH2O (−117.1–−98.5‰) values of quartz in stage II–IV show the fluid mixing with meteoric water. The S–Pb isotopic values (δ34 S = −2.7–0.8;206 Pb/204 Pb = 18.236–18.599;207 Pb/204 Pb = 15.504–15.557;208 Pb/204 Pb = 37.816–38.629) of pyrites indicate that the ore-forming materials are of magmatic origin. Fluid boiling and mixing may be the major mechanisms of ore precipitation. Zircon U–Pb age (172.1 ± 0.5 Ma) and geochemical data indicate that the ore-related granodiorites are I-type rocks formed in the subduction setting of the Paleo-Pacific Ocean Plate in the Early–Middle Jurassic. In conclusion, we propose that the Huaduoshan Cu–Mo prospect is a porphyry deposit and has potential for further exploration of porphyry Cu–Mo prospecting. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
15. Petrography, geochemistry, and Nd isotope systematics of metaconglomerates and matrix-rich metasedimentary rocks: implications for the provenance and tectonic setting of the Labrador Trough, Canada.
- Author
-
Henrique-Pinto, R., Guilmette, C., Bilodeau, C., Stevenson, R., and Carvalho, B.B.
- Subjects
PETROLOGY ,GEOCHEMISTRY ,NEODYMIUM isotopes ,ARENITES ,SEDIMENTARY rocks - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
16. Distinct Taconic, Salinic, and Acadian deformation along the Iapetus suture zone, Newfoundland Appalachians.
- Author
-
Zagorevski, A., McNicoll, V. J., and van Staal, C. R.
- Subjects
DEFORMATIONS (Mechanics) ,OROGENY ,ORDOVICIAN stratigraphic geology ,SILURIAN stratigraphic geology ,ACADIANS ,STRUCTURAL geology ,GEOCHEMISTRY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
- Full Text
- View/download PDF
17. Introduction to Special Issue of Canadian Journal of Earth Sciences: the Lake Nipigon Region Geoscience Initiative.
- Author
-
Easton, Mike, Hollings, Pete, and Rayner, Wally
- Subjects
EARTH sciences ,MINERALOGY ,LAND use ,GEOLOGICAL basins ,MINERAL industries ,STRUCTURAL geology ,GEOCHEMISTRY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
- Full Text
- View/download PDF
18. Petrogenesis of siliciclastic sediments and sedimentary rocks explored in three-dimensional Al2O3–CaO*+Na2O–K2O–FeO+MgO (A–CN–K–FM) compositional space.
- Author
-
Fedo, Christopher M. and Babechuk, Michael G.
- Subjects
SEDIMENTARY rocks ,CLASTIC rocks ,FELSIC rocks ,PETROGENESIS ,SEDIMENTS ,POTASSIUM ,CHEMICAL weathering - Abstract
Quantitatively determining the amount of chemical weathering within sedimentary rocks (and weathering profiles) took a major step forward with the creation of the chemical index of alteration (CIA) 40 years ago. The CIA relates the proportion of immobile aluminum to the mobile cations of calcium, sodium, and potassium and is grounded in empirical and modeled geochemical data for mineral reactions that occur during hydrolysis. However, the CIA should be applied cautiously because it is a one-dimensional value that in the most complex situations, as with clastic sedimentary rocks, homogenizes the compositional inputs of source, weathering, sorting, and diagenesis. Subsequently developed two-dimensional (2D) ternary diagrams (Al
2 O3 –CaO* +Na2 O–K2 O; Al2 O3 –CaO* +Na2 O+K2 O–FeO+MgO) permitted the capacity to explore mineralogical-geochemical pathways in data sets that may separate those inputs, but interpreting the ternary diagrams may be complicated because they differentiate and group certain elements. Here we develop a three-dimensional tetrahedral diagram (Al2 O3 –CaO* +Na2 O–K2 O–FeO+MgO, A–CN–K–FM) that incorporates the same critical elements and permits the simultaneous assessment of felsic and mafic rocks and minerals on the same diagram while retaining the ability to separate plagioclase from alkali feldspar and monitor post-depositional potassium changes. Using the tetrahedral plot, we show that both the CIA value and positions on the 2D ternary diagrams can generate potentially misleading interpretations without properly budgeting the ferromagnesian components in parallel. We first show how the tetrahedron works, then use it with numerous previously published examples to identify how the competing mafic and felsic inputs shape the composition of source rocks, weathering profiles, actively transporting sediment, paleosols, and sedimentary rocks in sedimentary petrogenesis. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
19. Petrogenesis and geodynamic significance of late Early Jurassic complex in Qinsai, Hainan Island, South China Sea.
- Author
-
Xu, Zhongjie, Kong, Jintao, Sun, Ningchen, Cheng, Rihui, and Zhang, Li
- Abstract
Whole-rock geochemical and U–Pb–Hf isotopic data were used to investigate the age, petrogenesis, and tectonic setting of a suite of gabbro–diorite–monzonite–syenite rock exposed in Qinsai area, Hainan Island. Zircon U–Pb dating shows that the gabbro and monzonite, respectively, crystallized at 179.5 ± 2.7 and 179.0 ± 2.3 Ma. The suite consists of shoshonitic alkaline intrusive rocks with SiO
2 content ranging from 41.7 to 63.4 wt%, with high U, K, and Pb and low Nb, Ta, and Ti. The suite is enriched in light rare earth elements relative to heavy rare earth elements. The gabbro has no obvious Eu anomaly but a positive Eu anomaly is evident in intermediate rocks. Zircon εHf (t) values are positive and have a wide variation (gabbro εHf (t) = +5.2 ± 8.2, monzonite εHf (t) = +4.7 ± 7.1). Gabbro and syenite are both likely derived from an enriched lithospheric mantle that was metasomatized by subduction fluids. Syenite evolved from the differentiation of gabbro, monzonite, and diorite. Collectively, these intrusive rocks formed in an extensional regime within an arc formed by subduction of the ancient Pacific plate beneath the Asian margin, which was accompanied by extensional thinning of the lithosphere. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
20. Late Triassic granites with mafic microenclaves in the East Kunlun Orogenic Belt, northwestern China: petrogenesis and implications for continental crust evolution and geodynamic evolution.
- Author
-
Xin, Wei, Ding, Zheng-jiang, Meng, Yuan-ku, Bo, Jun-wei, Li, Liang, and Mao, Guang-zhou
- Abstract
The magmatic source of the Late Triassic granites in the East Kunlun Orogenic Belt (EKOB) is controversial, which restricts our understanding of crustal evolution and geodynamic evolution in the EKOB. Therefore, this study conducts zircon U‒Pb isotope dating, major and trace geochemical analysis, electron microprobe analysis of feldspar and amphibole, and in situ zircon Hf isotope analysis of Xiangride host granites and their mafic microgranular enclaves (MMEs) in the EKOB to reveal their magmatic source and geodynamic implications. Zircon U‒Pb dating shows that the Xiangride host granites and the MMEs crystallized simultaneously at ca. 228–223 Ma. The MMEs show an igneous texture, finer grain size, higher crystallization temperature and water content, and lower oxygen fugacity than those of the host granite, suggesting that they were probably derived from two distinct primitive magmas. Therefore, the MMEs are considered the products of magma mixing between granitic and mafic magmas. The Xiangride host granites show high Sr/Y (42.0–73.1) and (La/Yb)
N (12.7–30.7) ratios, showing affinity with adakites derived from a thickened lower crust. Combined with the indistinguishable εHf (t) values (−3.47 to +0.08) from the coeval mafic rocks, it is concluded that they are derived from partial melting of juvenile thickened lower crust. The adakitic features of the Xiangride host granites and widespread coeval granites indicate the existence of a thickened lower crust before 228 Ma and delamination of the lower lithosphere is likely the geodynamic process resulting in the postcollisional extension regime. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
21. Geology, geochemistry, and apatite/titanite U–Pb geochronology of ca. 1.88 Ga alkaline ultrabasic dykes in the Southern Province near Sudbury, Ontario.
- Author
-
Kawohl, Alexander, Frimmel, Hartwig E., Whymark, Wesley E., Millonig, Leo J., and Gerdes, Axel
- Subjects
LASER ablation inductively coupled plasma mass spectrometry ,DIKES (Geology) ,SPHENE ,GEOCHEMISTRY ,GEOLOGICAL time scales ,TRACE elements ,GEOLOGY ,RARE earth metals - Abstract
The area northeast of Sudbury, Ontario, is well known for hosting one of the largest unexplained geophysical anomalies in the Canadian Shield, the Temagami Anomaly. In search of a geological explanation for this anomaly, low-grade metamorphic ultrabasic dykes have been discovered in the overlying Huronian Supergroup sedimentary rocks, both in outcrop and in a deep drill core. Here, we report on the first geochemical and geochronological data obtained on these dykes and compare these data with known magmatic units in and around the 1850 Ma impact-generated Sudbury Igneous Complex (SIC). The NW-striking dykes, which cut across sedimentary rocks of the ca. 2.3 Ga Cobalt Group, and which are, in turn, crosscut by pseudotachylitic breccia, are characterized by distinctively high concentrations of Ti, P, Nb, and Zr, highly fractionated rare earth element patterns (La/Yb
N 7.6–15.5), and a lack of crustal contamination (Nb/Th > 10). Such features are typical of modern ocean island basalts but very different from Palaeoproterozoic rocks previously documented in the wider region. Multigrain U–Pb laser ablation inductively coupled plasma mass spectrometry analyses performed on magmatic titanite and apatite with high Th/U ratios yielded 1876.0 ± 8.7 and 1880.9 ± 8.3 Ma, respectively, which we interpret as the intrusion age of the dykes. This interpretation is supported by similar whole-rock Sm-Nd model ages of 1890–2000 Ma (initial εNd +2.5). This magmatic event in the footwall of the SIC shortly before the impact was coeval with, and likely genetically related to, the 1.88–1.87 Ga Circum-Superior Large Igneous Province. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
22. A high-resolution, continuous δ13C record spanning the Ordovician-Silurian boundary on Anticosti Island, eastern Canada1.
- Author
-
Mauviel, Alain, Desrochers, André, and Jin, Jisuo
- Subjects
CHEMOSTRATIGRAPHY ,GEOCHEMISTRY ,STRATIGRAPHIC geology ,ANTICOSTI Island aster ,EARTH sciences - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2016
- Full Text
- View/download PDF
23. Geochemical constraints on magmatic and metallogenic processes: Iskut River Formation, volcanogenic massive sulfide-hosting basalts, NW British Columbia, Canada.
- Author
-
Barresi, Tony, Nelson, JoAnne L., Dostal, Jaroslav, and Gibson, Harold
- Subjects
GEOCHEMISTRY ,MAGMATISM ,METALLOGENY ,GEOLOGICAL formations ,BASALT - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2015
- Full Text
- View/download PDF
24. Geochronology, geochemistry, and petrogenesis of Early Cretaceous highly differentiated I-type granites in the central Great Xing'an Range, northeastern China.
- Author
-
Lan, Li-xue, Dong, Yu, Ge, Wen-chun, Gao, Yan, Ji, Zheng, Jing, Yan, Bi, Jun-hui, and Zhou, Hong-ying
- Subjects
GEOLOGICAL time scales ,GEOCHEMISTRY ,LASER ablation inductively coupled plasma mass spectrometry ,RARE earth metals ,GRANITE ,RARE earth ions ,PLAGIOCLASE - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
- Full Text
- View/download PDF
25. Neodymium isotope mapping a polygenetic TTG batholith: failed back-arc rifting in the Central Metasedimentary Belt, southwestern Grenville Province.
- Author
-
Strong, Jacob W.D. and Dickin, Alan P.
- Subjects
NEODYMIUM isotopes ,BATHOLITHS ,GEOLOGICAL time scales ,RIFTS (Geology) ,ISOTOPIC analysis ,GEOCHEMISTRY ,CONTINENTAL margins - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
- Full Text
- View/download PDF
26. Geochronology, geochemistry, Sr–Nd–Hf isotope composition of the late Permian adakite in West Ujimqin, Inner Mongolia: petrogenesis and tectonic implications.
- Author
-
Fan, Yuxu, Xiao, Qinghui, Li, Tingdong, Cheng, Yang, Li, Yan, Guo, Lingjun, and Luo, Pengyue
- Subjects
GEOCHEMISTRY ,GEOLOGICAL time scales ,ADAKITE ,PETROGENESIS ,REGOLITH ,ISOTOPES ,RARE earth metals ,SIDEROPHILE elements - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
- Full Text
- View/download PDF
27. Discussion of the reply by R.L. Romer and U. Kroner on 'Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf'1.
- Subjects
GEOCHEMISTRY ,ORDOVICIAN Period ,SEDIMENTARY rocks ,CONTINENTAL shelf ,GEOLOGICAL time scales - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
28. Late Wisconsinan glacial history in the Bonaparte Lake map area, south-central British Columbia: implications for glacial transport and mineral exploration.
- Author
-
Plouffe, A., Bednarski, J.M., Huscroft, C.A., Anderson, R.G., McCuaig, S.J., and Fisher, Timothy
- Subjects
GLACIAL climates ,LAKE mapping ,MINERALOGY ,ICE sheets ,LANDFORMS ,SEDIMENTOLOGY ,GEOCHEMISTRY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
29. Basaltic to andesitic volcaniclastic rocks in the Blake River Group, Abitibi Greenstone Belt: 2. Origin, geochemistry, and geochronology12.
- Author
-
Ross, P.-S., McNicoll, V., Goutier, J., Mercier-Langevin, P., Dubé, B., and Polat, Ali
- Subjects
- *
BASALT , *VOLCANIC ash, tuff, etc. , *GEOCHEMISTRY , *GEOLOGICAL time scales , *CALDERAS , *SUBMARINE volcanoes - Abstract
In the Archean Blake River Group, mafic to intermediate fragmental units have controversially been proposed to have formed during the collapse of a giant submarine caldera. This paper describes and interprets these rocks, summarizing their physical characteristics, inferred origins, age relationships, and geochemical signatures. The widespread Stadacona member, south of Rouyn-Noranda, consists of several hundred metres of bedded volcaniclastic rocks interpreted to have been mostly deposited from aqueous density currents fed directly by explosive eruptions. The magmas involved in these eruptions were plagioclase-phyric, tholeiitic to transitional basalts. The similarly widespread D'Alembert tuff, in the northern part of the Blake River Group, shares many physical characteristics with the Stadacona member and is thought to have a similar origin. However, the D'Alembert tuff is approximately six million years younger than the Stadacona member. It is composed mostly of transitional to calc-alkaline andesites and basaltic andesites with very distinct trace element profiles. Volcaniclastic rocks from other areas, such as Tannahill Township in Ontario and the Monsabrais area in Quebec, are interpreted to represent mostly in situ to remobilized hyaloclastite, with no explosive eruptions involved in their genesis. Our observations and interpretations are not compatible with models in which the volcaniclastic units are emplaced during a catastrophic event in relation with the collapse of a giant caldera. Instead, the fragmental rocks were produced by various mechanisms at many distinct times during the evolution of the Blake River Group. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
30. Geochronology and geochemistry of Precambrian gneisses, metabasites, and pegmatite from the Tobacco Root Mountains, northwestern Wyoming craton, Montana.
- Author
-
Krogh, Thomas E., Kamo, Sandra L., Hanley, Thomas B., Hess, David F., Dahl, Peter S., and Johnson, Robert E.
- Subjects
GEOLOGICAL time scales ,GEOCHEMISTRY ,PRECAMBRIAN stratigraphic geology ,GNEISS ,METABASITE ,CRATONS ,PEGMATITES - Abstract
The Middle Mountain Metamorphic Domain of the Montana Metasedimentary Terrane, northwestern Wyoming Craton, within the northwestern Tobacco Root Mountains, mainly comprises migmatized tonalitic gneiss interlayered with amphibolitic (hornblende) gneiss, both of which are cut by metamorphosed mafic rocks. Together, these gneisses are defined as Middle Mountain Gneiss. Archean tonalitic gneiss from west of, and amphibolitic gneiss from east of, the Bismark Fault give, from chemically and air-abraded zircon grains, U-Pb ID-TIMS ages of 3325.5 ±1.7 and 3340 Ma, respectively. These results reflect primary magmatic ages and show that the Middle Mountain Gneiss extends into the northern area of the Central Fault Block, between the Bismark and Mammoth faults. Older crustal processes in the tonalitic gneiss are evidenced by inherited grains, the oldest of which is >3460 Ma. A metabasite hosted in tonalitic gneiss in the Bismark Fault selvage zone yields a zircon age of 2468 Ma, which is interpreted as the time of metamorphism. This date and other ca. 2470 Ma dates known in the region reflect a series of thermotectonic events designated here as the Beaverhead - Tobacco Root Orogeny. Geochemical evidence in the Central Fault Block metabasites suggests that their >2470 Ma precursors evolved in a back-arc - arc-rift setting, whereas their equivalents west of the Bismark Fault were largely mid-ocean ridge basalt-related tholeiites and east of the Central Fault Block were back-arc tholeiites showing some continental affinity. The metabasite was metamorphosed, deformed, and intruded by pegmatite at 1756 Ma during the Big Sky Orogeny. This orogenic event also produced new zircon growth in Archean tonalitic gneiss. Monazite with an age of 75 Ma, found at one location, reflects nearby intrusion of the Cretaceous Tobacco Root Batholith. Le domaine métamorphique de Middle Mountain dans le terrane métasédimentaire du Montana, nord-ouest du craton Wyoming, nord-ouest des monts Tobacco Root, comprend surtout des gneiss tonalitiques migmatisés interstratifiés avec des gneiss amphibolitiques (hornblende); les deux sont recoupés par des roches mafiques métamorphisées. Ensemble, ces gneiss forment le gneiss de Middle Mountain. Un gneiss tonalitique archéen provenant d'un site à l'ouest de la faille Bismark et un gneiss amphibolitique provenant d'un site à l'est de cette faille ont donné des âges U-Pb ID-TIMS respectifs de 3325,5 ±1,7 et 3340 Ma, sur des zircons prétraités par abrasion chimique ou par abrasion à l'air. Ces résultats reflètent des âges magmatiques primaires et montrent que le gneiss de Middle Mountain s'étend dans le secteur nord du Central Fault Block, entre les failles Bismark et Mammoth. Des processus plus anciens de la croûte dans le gneiss tonalitique sont mis en évidence par des grains hérités, dont le plus ancien date de >3460 Ma. Une métabasite encaissée dans un gneiss tonalitique dans la zone de salbande de la faille Bismark a donné un âge sur zircon de 2468 Ma, ce qui est interprété comme le moment du métamorphisme. Cette datation et d'autres autour de 2470 Ma connues dans la région sont le reflet d'une série d'événements thermo-tectoniques désignés ici sous l'appellation orogène Beaverhead - Tobacco Root. Les évidences géochimiques dans les métabasites du Central Fault Block suggèrent que leurs précurseurs >2470 Ma aient évolué dans un environnement d'arrière-arc - arc de distension, alors que leurs équivalents à l'ouest de la faille Bismark était largement des tholéiites reliés à des basaltes de dorsale médio-océanique et, à l'est du Central Fault Block, étaient des tholéiites d'arrière-arc montrant une certaine affinité continentale. La métabasite était métamorphisée, déformée et une pegmatite l'a pénétrée à 1756 Ma durant l'orogène Big Sky. Cet événement orogénique a aussi engendré une nouvelle croissance de zircons dans le gneiss tonalitique archéen. Une monazite, âgée de 75 Ma, trouvée à un site, reflète l'intrusion avoisinante du batholite Tobacco Root, au Crétacé. [ABSTRACT FROM AUTHOR]
- Published
- 2011
31. The Western Superior Province Lithoprobe and NATMAP transects: introduction and summary.
- Author
-
Percival, John A. and Helmstaedt, Herwart
- Subjects
GEOLOGICAL research ,CRATONS ,GREENSTONE belts ,GEOPHYSICS ,STRATIGRAPHIC geology ,GEOLOGICAL time scales ,GEOCHEMISTRY ,PETROLOGY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
32. Paleoproterozoic submarine intrabasinal rifting, Baffin Island, Nunavut, Canada: volcanic structure and geochemistry of the Bravo Lake Formation.
- Author
-
Johns, Shannon M., Helmstaedt, Herwart H., and Kyser, T. Kurtis
- Subjects
IGNEOUS rocks ,LAKES ,GEOCHEMISTRY ,VOLCANOES ,TRACE elements ,BASALT ,RARE earth metals - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
33. Geochemistry and U–Pb geochronology of the Williams Brook area, Tobique–Chaleur zone, New Brunswick: stratigraphic and geotectonic setting of gold mineralization.
- Author
-
Sánchez-Mora, D., McFarlane, C.R.M., Walker, J.A., and Lentz, D.R.
- Subjects
GONDWANA (Continent) ,GEOCHEMISTRY ,MAFIC rocks ,MINERALIZATION ,VOLCANIC ash, tuff, etc. ,GOLD - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
34. Evolution of 3.1 and 3.0 Ga volcanic belts and a new thermotectonic model for the Hopedale Block, North Atlantic craton (Canada).
- Author
-
James, D T, Kamo, S, and Krogh, T
- Subjects
GALLIUM ,GEOCHEMISTRY ,EARTH sciences ,LEAD compounds - Abstract
A new model for evolution of the Archean Hopedale Block, based on mapping and supporting U–Pb geochronological and geochemical studies, is highlighted by (i) ca. 3.25 Ga emplacement of igneous precursors of Maggo Gneiss; (ii) >3.1 Ga, high-grade Hopedalian metamorphism and attendant deformation; (iii) emplacement of the Hopedale mafic dykes; (iv) 3.1 Ga deposition of Hunt River volcanic rocks; (v) ca. 3.0 Ga deposition of Florence Lake volcanic rocks; (vi) 2.88–2.96 Ga, greenschist- to amphibolite-facies Fiordian metamorphism and formation of penetrative, northeast-striking Fiordian structures; and (vii) emplacement of a suite of 2.89–2.83 Ga tonalite to granite intrusions, which partially overlap and locally postdate Fiordian metamorphism and deformation. The Hunt River and Florence Lake volcanic sequences are different in age but similar in most other respects. The former consists mainly of amphibolite-facies mafic metavolcanic rocks and lesser amounts of komatiite flows and metasedimentary and 3105 ± 3 Ma felsic volcanic rocks. The Florence Lake volcanic belt consists mainly of greenschist- to amphibolite-facies mafic metavolcanic rocks, lesser amounts of felsic metavolcanic rocks, dated at 2979 ± 1 and 2990 ± 2 Ma, komatiite flows, and rare metasedimentary rocks. The similarity of rock types, field relationships between different rock types, such as the common association of ultramafic and felsic metavolcanic rocks, and the chemistry of volcanic rocks in both belts suggest a common tectonic setting for each belt. A model involving episodic volcanism, separated by 100 Ma, in ensialic basins is consistent with the dominance of tholeiitic basalt and an abundance of pre-volcanic basement.Un nouveau modèle pour l'évolution du bloc Hopedale (Archéen), basé sur la cartographie et supportant les études sur la géochronologie et la géochimie U–Pb, est mis en évidence par (i) la mise en place vers 3,25 Ga des précurseurs ignés du gneiss Maggo, (ii) le métamorphisme élevé de Hopedale, vers 3,1 Ga, et la déformation qui l'accompagne (iii) la mise en place des dykes mafiques Hopedale, (iv) la déposition à 3,1 Ga des roches volcaniques de Hunt River, (v) la déposition vers 3,0 Ga des roches volcaniques de Florence Lake, (vi) le métamorphisme fiordien, du faciès de schistes verts au faciès des amphibolites, et la formation de structures fiordiennes pénétrantes et de direction nord-est, de 2,88 à 2,96 Ga et (vii) la mise en place d'une suite d'intrusions de tonalite à granite, 2,89 à 2,83 Ga; ces intrusions recouvrent en partie le métamorphisme et la déformation fioridiens et, par endroits, elles leur sont plus tardives. Les séquences volcaniques de Hunt River et de Florence Lake sont d'âges différents mais elles sont similaires selon la plupart des autres aspects. La séquence de Hunt River consiste surtout en roches volcaniques mafiques au faciès des amphibolites avec moins de coulées komatiitiques, des roches métasédimentaires et des roches volcaniques âgées de 3105 ± 3 Ma. La ceinture volcanique de Florence Lake comprend surtout des roches métavolcaniques mafiques du faciès des schistes verts au faciès des amphibolites et des quantités moindres de roches métavolcaniques felsiques âgées de 2979 ± 1 et 2990 ± 2 Ma, des coulées komatiitiques et de rares roches métasédimentaires. La similitude des types de roches, les relations de terrain entre les divers types de roches, telles que l'association fréquente des roches métavolcaniques ultramafiques et felsiques, ainsi que la chimie des roches volcaniques dans les deux ceintures suggèrent un contexte tectonique commun. Un modèle impliquant des épisodes de volcanisme, séparés par 100 Ma, dans des bassins ensialiques concorde avec la dominance de basalte tholéiitique et une abondance de socle prévolcanique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
35. Quaternary geology of the Babine porphyry copper district: implications for geochemical exploration.
- Author
-
Levson, Victor M
- Subjects
GEOLOGY ,NATURAL history ,EARTH sciences ,LAKES ,GEOCHEMISTRY - Abstract
The Quaternary stratigraphy of the Babine Lake region is characterized by a Late Wisconsinan succession of advance-phase glaciolacustrine sediments, glaciofluvial deposits, and till. Pollen data from a rare new interglacial site suggest a colder than present Middle Wisconsinan climate. Ice flow during the last glaciation was dominantly southeasterly, but in the Babine Range a regional, westerly ice-flow event occurred. Evidence for westerly flow diminishes eastward of Babine Lake, suggesting that the valley was near the eastward limit of an interior ice divide. Deglacial sediments include ice-marginal debris-flow, glaciofluvial, and glaciolacustrine sediments. Raised-delta elevations indicate that Glacial Lake Babine extended nearly 150 m above present lake level to 850 m asl, and higher, earlier phases may have existed locally. A variety of Holocene deposits cap the Quaternary succession. Glaciation has important implications for exploration in this copper-producing area. Southeasterly glacial dispersal patterns dominate, despite a regionally complex ice-flow history. Highly anomalous concentrations of copper occur in tills down-ice of most known bedrock copper occurrences, and a number of similarly anomalous till sites with no known copper sources have been identified in drift-covered areas. Exploration problems due to the thick and complex surficial cover can be overcome by selective sampling of basal tills, the composition of which clearly reflects the presence of buried mineral deposits. The effectiveness of till geochemistry as a method for locating buried mineralization in the region will be enhanced by careful selection of sample media and by a clear understanding of the glacial history.La stratigraphie du Quaternaire de la région du lac Babine est caractérisée par une séquence de sédiments glacio-lacustres de phase avancée, de dépôts fluvio-glaciaires et de till datant du Wisconsinien tardif. Des données de pollen d'un rare nouveau site interglaciaire suggèrent qu'au Wisconsinien moyen le climat était plus froid que présentement. Au cours de la dernière glaciation, l'écoulement de la glace était à prédominance sud-est mais, dans la chaîne Babine, il y eut un écoulement régional vers l'ouest. L'évidence pour un écoulement vers l'ouest diminue à l'est du lac Babine, suggérant que la vallée était près de la limite est d'une ligne intérieure de partage glaciaire. Des sédiments de déglaciation comprennent un écoulement de débris en marge du glacier, des sédiments fluvio-glaciaires et glacio-lacustres. Des élévations de deltas soulevés indiquent que le lac glaciaire Babine s'étendait près de 150 m au-dessus du niveau actuel du lac, à 850 m au-dessus du niveau de la mer, et que des phases plus précoces se sont retrouvées localement encore plus haut. Divers dépôts datant de l'Holocène reposent sur la séquence quaternaire. La glaciation a des implications importantes pour l'exploration dans cette région productrice de cuivre. Les patrons de dispersion glaciaire vers le sud-est dominent malgré un historique régional complexe d'écoulement glaciaire. Des concentrations hautement anomales de cuivre se retrouvent dans les tills en aval glaciaire de la plupart des occurrences connues du cuivre dans le roc et une nombre de sites également anomaux de tills ont été identifiées dans des régions recouvertes de dépôts morainiques sans qu'on puisse les relier à des dépôts connus de cuivre. Les problèmes d'exploration causés par le couvert épais et complexe peuvent être surmontés par un échantillonnage sélectif du till de fond dont la composition reflète clairement la présence de gisements minéraux enfouis. L'efficacité de la géochimie des tills comme méthode pour localiser de la minéralisation enfouie dans la région sera rehaussée par le choix judicieux des outils d'échantillonnage et par une bonne compréhension de l'historique glaciaire.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
36. Volcanic reconstruction and geochemistry of the Powderhouse formation in the Paleoproterozoic VMS-hosting Chisel sequence, Snow Lake, Manitoba, Canada.
- Author
-
Friesen, V.C., DeWolfe, Y.M., and Gibson, H.L.
- Subjects
GEOCHEMISTRY ,LITHOFACIES ,VOLCANIC ash, tuff, etc. ,RHYOLITE ,LAKE sediments - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
37. Identifying groundwater discharge zones in the Central Mackenzie Valley using remotely sensed optical and thermal imagery.
- Author
-
Glass, Brittney K., Rudolph, David L., Duguay, Claude, and Wicke, Andrew
- Subjects
SHALE oils ,HYDRAULIC measurements ,CLIMATE change ,PETROLEUM prospecting ,GEOCHEMISTRY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
38. Discussion of 'Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf'1.
- Author
-
Waldron, John W.F., White, Chris E., and Murphy, Brendan
- Subjects
- *
GEOCHEMISTRY , *ORDOVICIAN Period , *SEDIMENTARY rocks , *ATMOSPHERIC models , *GROUPS (Stratigraphy) , *WATER depth - Abstract
The paper 'Geochemical signature of Ordovician Mn-rich sedimentary rocks on the Avalonian shelf' (Romer et al., published in 2011) describes six samples of which four are from the Meguma Supergroup of Nova Scotia. Previous work indicates that these samples are Cambrian and that they were deposited in a deep-water turbidite basin ('Megumia'), not on the Avalonian shelf. The geochemical data support models for Mn concentration, involving oxidation and reduction in a sedimentary environment but do not constrain water depth. Likely correlatives are in the Cambrian of North Wales and not in the European localities sampled by the authors. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
39. Contact-style magmatic sulphide mineralisation in the Labrador Trough, northern Quebec, Canada: implications for regional prospectivity.
- Author
-
Smith, W.D., Maier, W.D., and Bliss, I.
- Subjects
SULFIDES ,CHROMITE ,SULFIDE minerals ,GEOCHEMISTRY ,ORES - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
40. Chlorine isotopes unravel conditions of formation of the Neoproterozoic rock salts from the Salt Range Formation, Pakistan.
- Author
-
Hussain, Syed Asim, Han, Feng-Qing, Han, Jibin, Khan, Hawas, and Widory, David
- Subjects
CHLORINE isotopes ,ROCK salt ,FLUID inclusions ,EARTH system science ,THRUST belts (Geology) ,ISOTOPIC fractionation ,GEOCHEMISTRY ,INDUCTIVELY coupled plasma atomic emission spectrometry - Abstract
The article presents a study related to the chlorine isotopes unravel conditions of formation of the Neoproterozoic rock salts from the Salt Range Formation in Pakistan. It mentions that the evaporites in the Salt Range area are Br-rich and precipitated from seawater under arid climate conditions. It also mentions that chlorine is one of the most abundant elements in many geofluids and one of the major volatile constituents on Earth.
- Published
- 2020
- Full Text
- View/download PDF
41. Petrogenesis of early Permian granitic dykes in the Wulanhuduge area, central Inner Mongolia, North China: constraints from geochronology, geochemistry, and Sr–Nd–Pb isotopes.
- Author
-
Zhang, Xiang-xin, Gao, Yong-feng, and Lei, Shi-he
- Subjects
TRACE elements ,SUTURE zones (Structural geology) ,RARE earth metals ,GEOCHEMISTRY ,LASER ablation inductively coupled plasma mass spectrometry - Abstract
The article presents a study related to the petrogenesis of early Permian granitic dykes in the Wulanhuduge area, central Inner Mongolia, North China. It mentions that the Ondor Sum subduction–accretion complex comprises the blueschist-bearing metamorphic complex and ophiolitic sequence; and the Bainaimiao arc is characterized by the Middle Ordovician to early Silurian volcano-sedimentary sequence and arc magmatic rocks.
- Published
- 2020
- Full Text
- View/download PDF
42. Localisation of the brittle Bathurst fault on pre-existing fabrics: a case for structural inheritance in the northeastern Slave craton, western Nunavut, Canada.
- Author
-
Ma, Svieda M., Kellett, Dawn A., Godin, Laurent, and Jercinovic, Michael J.
- Subjects
GEOCHEMISTRY ,PHYSIOGRAPHIC provinces ,STRUCTURAL geology ,RARE earth metals ,MUSCOVITE ,CRATONS ,HORNBLENDE - Abstract
The article presents a study related to the localization of the brittle Bathurst fault on pre-existing fabrics. It mentions that the Bathurst fault is a component of the Bathurst–MacDonald conjugate fault system and displaces the thelon tectonic zone (TTZ) and paleoproterozoic Kilohigok basin and is overlain by the Thelon basin.
- Published
- 2020
- Full Text
- View/download PDF
43. Rock and age relationships within the Talkeetna forearc accretionary complex in the Nelchina area, southern Alaska.
- Author
-
Barefoot, John, Nadin, Elisabeth S., Newberry, Rainer J., and Camacho, Alfredo
- Subjects
GEOLOGICAL time scales ,RARE earth metals ,ACCRETIONARY wedges (Geology) ,TRACE elements ,LASER ablation inductively coupled plasma mass spectrometry ,GEOCHEMISTRY - Abstract
The article presents a study related to rock and age relationships within the Talkeetna forearc accretionary complex in the Nelchina area, southern Alaska. It mentions that Complexities of mélange sections of accretionary prisms include varying degrees of metamorphism of blocks that also have variable origins and different metamorphic paths, preserved within a matrix that may have a different metamorphic grade.
- Published
- 2020
- Full Text
- View/download PDF
44. Geochronology and geochemistry of igneous rocks in the southeastern Lesser Xing'an Range, northeastern China: petrogenesis and implications for the early Mesozoic tectonic evolution.
- Author
-
Qin, Jin-hua, Liu, Cui, and Deng, Jin-fu
- Subjects
LASER ablation inductively coupled plasma mass spectrometry ,IGNEOUS rocks ,DIORITE ,RARE earth metals ,GEOCHEMISTRY ,ALKALINE earth metals ,GEOLOGICAL time scales ,AMALGAMATION - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
45. New constraints on the genesis and geodynamic setting of the Wulong gold deposit, Liaodong Peninsula, northeast China: evidence from geology, geochemistry, fluid inclusions, and C–H–O–S–Pb isotopes1,2.
- Author
-
Cheng, Xihui, Xu, Jiuhua, Yang, Fuquan, Zhang, Guorui, Zhang, Hui, Bian, Chunjing, and Xue, Qingpo
- Subjects
FLUID inclusions ,GEOCHEMISTRY ,GEOLOGY ,QUARTZ ,GOLD ores ,LEAD isotopes ,SULFIDE minerals ,SALINITY - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
46. Geochemistry and mineralogy of Quaternary sediments in the northern Bohai Bay Basin, North China: implications for provenance and climate change.
- Author
-
Wang, Shengdong, Deng, Xiaohong, Dai, Peng, Wu, Junjie, Zhang, Jie, Zhang, Quan, and Wang, Zhong
- Subjects
GEOCHEMISTRY ,RARE earth metals ,MINERALOGY ,CLIMATE change ,IGNEOUS rocks ,PROVENANCE (Geology) ,SEDIMENTARY rocks - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
47. Geochemistry of the Eocene clastic sediments (Suonahu Formation) in the North Qiangtang Basin, Tibet: implications for paleoclimate conditions, provenance and tectonic setting.
- Author
-
Shen, Lijun, Wang, Jian, Shen, Hualiang, Fu, Xiugen, Wan, Youli, Song, Chunyan, Zeng, Shengqiang, Dai, Jie, and Wang, Dong
- Subjects
GEOCHEMISTRY ,RARE earth metals ,FELSIC rocks ,CLASTIC rocks ,IGNEOUS rocks ,ORGANIC geochemistry ,TRACE elements ,AMALGAMATION - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
48. Petrogenesis and tectonic setting of the Huhetaoergai granitic pluton in the northern Ya-Gan Fault zone, northern Alxa, China: constraints from whole-rock geochemistry, zircon U–Pb ages, and Hf isotope compositions.
- Author
-
Xie, Fenquan, Wu, Qianhong, Wang, Lidong, Xiao, Wenzhou, Cao, Jingya, Shi, Zhaoxia, and Song, Jiajia
- Subjects
IGNEOUS intrusions ,FAULT zones ,GEOCHEMISTRY ,ZIRCON ,PETROGENESIS ,ISOTOPES - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
49. Zircon U–Pb chronology, geochemistry, and petrogenesis of the high Nb–Ta alkaline rhyolites at the Tuohe Tree Farm, northern Volcanic Belt, Great Xing'an Range, China.
- Author
-
Sun, Guosheng, Zhao, Tianxue, Jin, Ruixiang, and Wang, Qinghai
- Subjects
GEOCHEMISTRY ,RARE earth metals ,TREE farms ,TRACE elements ,METAMORPHIC rocks ,PETROGENESIS - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
50. Up, down, or sideways: emplacement of magmatic Fe–Ni–Cu–PGE sulfide melts in large igneous provinces.
- Author
-
Lesher, C.M.
- Subjects
IGNEOUS provinces ,SULFIDE ores ,GEOCHEMISTRY ,SCIENCE conferences ,PHYSIOGRAPHIC provinces ,SULFIDES ,EARTH sciences - Abstract
The article discusses geological, geochemical, isotopic, thermodynamic, and fluid dynamic constraints require that the sulfide in most high-grade magmatic Ni–Cu–PGE deposits in large igneous provinces (LIPs). Topics include the broad consensus on the need to incorporate crustal S to generate high-grade Ni–Cu–PGE deposits in LIPs; and these points suggest that Fe–Ni–Cu–PGE sulfide melts have rarely ever transported upwards.
- Published
- 2019
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.