Timing of Precambrian melt depletion and Phanerozoic refertilization events in the lithospheric mantle of the Wyoming Craton and adjacent Central Plains Orogen

Lithos ◽  
2004 ◽  
Vol 77 (1-4) ◽  
pp. 453-472 ◽  
Author(s):  
Richard W. Carlson ◽  
Anthony J. Irving ◽  
Daniel J. Schulze ◽  
B.Carter Hearn Jr.
Keyword(s):  
Lithospheric Mantle ◽  
Central Plains ◽  
Wyoming Craton

Electromagnetic images of the Trans-Hudson orogen: the North American Central Plains anomaly revealed

2005 ◽  
Vol 42 (4) ◽  
pp. 457-478 ◽  
Author(s):  
Alan G Jones ◽  
Juanjo Ledo ◽  
Ian J Ferguson
Keyword(s):  
Electrical Properties ◽  
North American ◽  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Three Dimensional ◽  
Conductivity Anomaly ◽  
Central Plains ◽  
Slave Craton ◽  
The North ◽  
Kimberlite Field

Magnetotelluric studies of the Trans-Hudson orogen over the last two decades, prompted by the discovery of a significant conductivity anomaly beneath the North American Central Plains (NACP), from over 300 sites yield an extensive database for interrogation and enable three-dimensional information to be obtained about the geometry of the orogen from southern North Dakota to northern Saskatchewan. The NACP anomaly is remarkable in its continuity along strike, testimony to along-strike similarity of orogenic processes. Where bedrock is exposed, the anomaly can be associated with sulphides that were metamorphosed during subduction and compression and penetratively emplaced deep within the crust of the internides of the orogen to the boundary of the Hearne margin. A new result from this compilation is the discovery of an anomaly within the upper mantle beginning at depths of ~80–100 km. This lithospheric mantle conductor has electrical properties similar to those for the central Slave craton mantle conductor, which lies directly beneath the major diamond-producing Lac de Gras kimberlite field. While the Saskatchewan mantle conductor does not directly underlie the Fort à la Corne kimberlite, which is associated with the Sask craton, the spatial correspondence is close.

Varieties of eclogites and their positions in the cratonic mantle lithosphere revealed by Jd-Di thermobarometry and trace element geochemistry

2021 ◽  
Author(s):  
Igor Ashchepkov ◽  
Alla Logvinova ◽  
Zdislav Spetsius ◽  
Theodoros Ntaflos ◽  
Hilary Downes ◽  
...  
Keyword(s):  
Trace Element ◽  
Lithospheric Mantle ◽  
Middle Part ◽  
Trace Element Geochemistry ◽  
Mantle Lithosphere ◽  
Ministry Of Education ◽  
Element Geochemistry ◽  
Wyoming Craton ◽  
Partial Melts ◽  
Diamond Inclusions

<p>The PT conditions and position of different groups of eclogites in the subcratonic lithospheric mantle (SCLM) worldwide has been established using clinopyroxene Jd-Di thermobarometry for different cratons and kimberlite localities. Beneath Siberia, Fe-eclogites found within the 3.0-4.0 GPa  and  were probably formed in Early Archean times forming the base of the lithosphere. In the Middle and Late Archean, eclogites were melted during subduction creating restite and cumulates from partial melts traced ascending channels.</p><p>High-Mg eclogites (partial melts or arc cumulates) are related to low-T geotherms. Melt-metasomatized eclogites trace a high-T geotherm and are often close to the middle part of the mantle lithosphere. Abundant eclogitic diamond inclusions from Siberia also mostly belong to the middle part of the lithosphere. </p><p>Ca-rich eclogites from Precambrian kimberlites of India are located in the middle lithospheric mantle whereas those entrained in Phanerozoic magmas are derived from the lithosphere base. In the Wyoming craton, kimberlites carry eclogite xenoliths captured from the 4.0-2.5 GPa interval.  In mantle lithosphere sampled by Proterozoic kimberlites, Ca-rich eclogites and grospydites occur in the 4.0-5.0 GPa interval. South Africa HT eclogite and diamond inclusions from the Proterozoic Premier kimberlites are derived from the deeper part of the mantle lithosphere and trace a high-T geotherm at depths of 7.0-4.0 GPa showing an increase in Fe upwards in the mantle section. Similar trends are common beneath the Catoca cluster kimberlites in Angola.</p><p>Mantle eclogites have clinopyroxenes and garnet trace element patterns with opposite inclinations determined by KDs with melts. Flatter and bell-like REE patterns with Eu anomalies? HFSE troughs and U, Pb peaks are common for MORB-type basaltic eclogites. High-Mg eclogites show less fractionated incompatible element patterns.  LILE-enrichments and HFSE troughs are typical for kyanite-bearing eclogites. Clinopyroxenes from diamond-bearing eclogites show lower REE and troughs in Nb and Zr, peaks in Pb and U concentrations compared to barren eclogites with round smooth trace element patterns and small depressions in Pb and Ba.</p><p>Support: RFBR 19-05-00788,  Russian Ministry of Education and Science</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.2c9ebbff3c0067455141161/sdaolpUECMynit/12UGE&app=m&a=0&c=4b235af5b7a8029fc48da92cba3afd9d&ct=x&pn=gnp.elif&d=1" alt=""></p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d13207104c0065755141161/sdaolpUECMynit/12UGE&app=m&a=0&c=d8f9503af82277872a4263e84ff9e0cf&ct=x&pn=gnp.elif&d=1" alt=""></p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.6b7fb9204c0063955141161/sdaolpUECMynit/12UGE&app=m&a=0&c=6b87575d150326ed00a773ccd740ef07&ct=x&pn=gnp.elif&d=1" alt=""></p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d6683a304c0060165141161/sdaolpUECMynit/12UGE&app=m&a=0&c=d034421517782917a447efa1c07c6281&ct=x&pn=gnp.elif&d=1" alt=""></p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.336759404c0065265141161/sdaolpUECMynit/12UGE&app=m&a=0&c=b4a9255ae696984c788c9868caf7be97&ct=x&pn=gnp.elif&d=1" alt=""></p>

Preferential localized thinning of lithospheric mantle in the melt-poor Malawi Rift

2020 ◽  
Vol 13 (8) ◽  
pp. 584-589
Author(s):  
Emily Hopper ◽  
James B. Gaherty ◽  
Donna J. Shillington ◽  
Natalie J. Accardo ◽  
Andrew A. Nyblade ◽  
...  
Keyword(s):  
Lithospheric Mantle
Sign in / Sign up

Export Citation Format

Share Document