Wyoming Craton Mantle Lithosphere: Reconstructions Based on Xenocrysts from Sloan and Kelsey Lake Kimberlites

Ashchepkov, Igor; Downes, Hilary; Mitchell, Roger H.; Vladykin, N. V.; Coopersmith, H. G.; Palessky, S. V.

doi:10.1007/978-81-322-1170-9_2

Cited by 4 publications

(4 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although mantle xenoliths have been recovered from volcanic rocks in and around this area [e.g., Eggler et al , ; Carlson et al , ; Schulze et al , ; Ashchepkov et al , ], they are rare, of Paleozoic age, highly heterogenous, and therefore provide information on only a limited portion of the deep mantle at the time of extrusion. We note, however, that fertile lherzolites and Fe‐rich eclogites are common lithologies in these xenolith suites [e.g., Schulze et al , ; Ashchepkov et al , ], and therefore potential candidates for explaining the relatively dense and fast nature of this mantle region. However, the questions of how and when this portion of mantle acquired its present‐day fertile characteristics, as well as the role of Laramide and post‐Laramide processes, remain open to debate.…”

Section: Discussionmentioning

confidence: 99%

3‐D multiobservable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle: III. Thermochemical tomography in the Western‐Central U.S.

et al. 2016

View full text Add to dashboard Cite

We apply a novel 3‐D multiobservable probabilistic tomography method that we have recently developed and benchmarked, to directly image the thermochemical structure of the Colorado Plateau and surrounding areas by jointly inverting P wave and S wave teleseismic arrival times, Rayleigh wave dispersion data, Bouguer anomalies, satellite‐derived gravity gradients, geoid height, absolute (local and dynamic) elevation, and surface heat flow data. The temperature and compositional structures recovered by our inversion reveal a high level of correlation between recent basaltic magmatism and zones of high temperature and low Mg# (i.e., refertilized mantle) in the lithosphere, consistent with independent geochemical data. However, the lithospheric mantle is overall characterized by a highly heterogeneous thermochemical structure, with only some features correlating well with either Proterozoic and/or Cenozoic crustal structures. This suggests that most of the present‐day deep lithospheric architecture reflects the superposition of numerous geodynamic events of different scale and nature to those that created major crustal structures. This is consistent with the complex lithosphere‐asthenosphere system that we image, which exhibits a variety of multiscale feedback mechanisms (e.g., small‐scale convection, magmatic intrusion, delamination, etc.) driving surface processes. Our results also suggest that most of the present‐day elevation in the Colorado Plateau and surrounding regions is the result of thermochemical buoyancy sources within the lithosphere, with dynamic effects (from sublithospheric mantle flow) contributing only locally up to ∼15–35%.

show abstract

Section: Discussionmentioning

confidence: 99%

3‐D multiobservable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle: III. Thermochemical tomography in the Western‐Central U.S.

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The southern site erupted through Proterozoic crust just south of the Wyoming craton. These samples define a cool Devonian geotherm (Eggler et al, 1988;Ashchepkov et al, 2013), originate from depths as great as ∼200 km (Eggler et al, 1988), and incorporate Archean xenoliths from the greatest depths (Schulze et al, 2008). That is, these xenoliths define a Devonian craton of typical age, thickness and thermal structure (Artemieva, 2009) (Fig.…”

Section: Mantle Xenolithsmentioning

confidence: 98%

Recent craton growth by slab stacking beneath Wyoming

Humphreys

Schmandt

Bezada

et al. 2015

Earth and Planetary Science Letters

View full text Add to dashboard Cite

Available online xxxx Editor: P. Shearer Keywords: Wyoming craton Shatsky conjugate tomography Laramide Sevier Colorado Mineral BeltSeismic tomography images high-velocity mantle beneath the Wyoming craton extending to >250 km depth. Although xenoliths and isostatic arguments suggest that this mantle is depleted of basaltic component, it is not typical craton: its NE elongate shape extends SW of the Wyoming craton; xenoliths suggest that the base of Archean mantle was truncated from ∼180-200 to ∼140-150 km depth since the Devonian, and that the deeper mantle is younger than ∼200 Ma. The Sevier-Laramide orogeny is the only significant Phanerozoic tectonic event to have affected the region, and presumably caused the truncation. Apparently, the base of the Wyoming craton was removed and young, depleted mantle was emplaced beneath the Wyoming craton during the Sevier-Laramide orogeny. We suggest that the Wyoming craton experienced a ∼75 Ma phase of growth through a three-stage process. First, flat-slab subduction removed 40-50 km off the base of the Archean Wyoming craton. This was followed by emplacement of basaltdepleted ocean plateau mantle lithosphere of the Shatsky Rise conjugate, which arrived in the early Laramide. The geologic recorded of vertical motion in the Wyoming region suggests that the plateau's crust escaped into the Earth's interior at 70-75 Ma. Initiation of Colorado Mineral Belt magmatism at this time may represent a slab rupture through which the ocean crust escaped.

show abstract

“…Mantle xenoliths in our study area are found near the north and south margins of the Wyoming craton (Figures 1a and 1c). Xenoliths sourced from up to 250 km depth show that much of the root is defined by a cold geotherm (35-44 mW/m 2 ) and was depleted in Archean or Paleoproterozoic times down to 200 km depth [Eggler et al, 1987a;Carlson and Irving, 1994;Carlson et al, 1999Carlson et al, , 2004Kuehner and Irving, 1999;Hearn, 2004;Aschepkov et al, 2013]. However, extensive metasomatism and refertilization has also occurred in multiple episodes from the Archean to the Cenozoic [Carlson and Irving, 1994;Carlson et al, 1999Carlson et al, , 2004Downes et al, 2004;Hearn, 2004].…”

Section: Cratonic Mantle Seismic Velocity Discontinuitiesmentioning

confidence: 99%

The meaning of midlithospheric discontinuities: A case study in the northern U.S. craton

Hopper

Fischer

2015

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Converted wave imaging has revealed significant negative velocity gradients, often termed midlithospheric discontinuities, within the thick, high‐velocity mantle beneath cratons. In this study, we investigate the origins and implications of these structures with high‐resolution imaging of mantle discontinuities beneath the Archean Wyoming, Superior and Medicine Hat, and Proterozoic Yavapai and Trans‐Hudson terranes. Sp phases from 872 temporary and permanent broadband stations, including the EarthScope Transportable Array, were migrated into three‐dimensional common conversion point stacks. Four classes of discontinuities were observed. (1) A widespread, near‐flat negative velocity gradient occurs largely at 70–90 km depth beneath both Archean and Proterozoic cratons. This structure is consistent with the top of a frozen‐in layer of volatile‐rich melt. (2) Dipping negative velocity gradients are observed between 85 and 200 km depth. The clearest examples occur at the suture zones between accreted Paleoproterozoic Yavapai arc terranes and the Wyoming and Superior cratons. These interfaces could represent remnant subducting slabs, and together with eclogite in xenoliths, indicate that subduction‐related processes likely contributed to cratonic mantle growth. (3) Sporadic positive velocity gradients exist near the base of the lithospheric mantle, perhaps due to laterally variable compositional layering. (4) In contrast to off‐craton regions, clear Sp phases are typically not seen at lithosphere‐asthenosphere boundary depths beneath Archean and Proterozoic terranes, consistent with a purely thermal contrast between cratonic mantle lithosphere and asthenosphere.

show abstract

Wyoming Craton Mantle Lithosphere: Reconstructions Based on Xenocrysts from Sloan and Kelsey Lake Kimberlites

Cited by 4 publications

References 55 publications

3‐D multiobservable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle: III. Thermochemical tomography in the Western‐Central U.S.

3‐D multiobservable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle: III. Thermochemical tomography in the Western‐Central U.S.

Recent craton growth by slab stacking beneath Wyoming

The meaning of midlithospheric discontinuities: A case study in the northern U.S. craton

Contact Info

Product

Resources

About