Fate of the lower lithosphere during shallow-angle subduction: The Laramide example

Chapman, Alan D.; Rautela, Ojashvi; Shields, Jessie E.; Ducea, Mihai N.; Saleeby, Jason B.

doi:10.1130/gsatg412a.1

Cited by 27 publications

(13 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…beneath the Mojave region at ca. 65 Ma (e.g., Chapman et al, 2020b), and they are in good agreement with more recently proposed reconstructions based on the presence of Laramide-aged lithospheric xenoliths from central Arizona that were likely endemic to the Mojave region (Chapman et al, 2020a).…”

Section: Tectonic Settingsupporting

confidence: 89%

“…Xenoliths from central Arizona, hypothesized to be lower-arc crust derived from the Mojave at ca. 75 Ma, corroborate this interpretation (Chapman et al, 2020a). Following this line of reasoning, the Late Cretaceous igneous rocks in the Mojave Desert are not so unlike all of the other plutons of Late Cretaceous age in the Sierra Nevada batholith, although the Mojave magmatic pulse was apparently smaller and ~10 m.y.…”

Section: Tectonic Settingsupporting

confidence: 52%

See 1 more Smart Citation

Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

et al. 2021

View full text Add to dashboard Cite

The Mojave Desert region is in a critical position for assessing models of Laramide orogenesis, which is hypothesized to have initiated as one or more seamounts subducted beneath the Cretaceous continental margin. Geochronological and geochemical characteristics of Late Cretaceous magmatic products provide the opportunity to test the validity of Laramide orogenic models. Laramide-aged plutons are exposed along a transect across the Cordilleran Mesozoic magmatic system from Joshua Tree National Park in the Eastern Transverse Ranges eastward into the central Mojave Desert. A transect at latitude ∼33.5°N to 34.5°N includes: (1) the large upper-crustal Late Cretaceous Cadiz Valley batholith, (2) a thick section of Proterozoic to Jurassic host rocks, (3) Late Cretaceous stock to pluton-sized bodies at mesozonal depths, and (4) a Jurassic to Late Cretaceous midcrustal sheeted complex emplaced at ∼20 km depth that transitions into a migmatite complex truncated along the San Andreas fault. This magmatic section is structurally correlative with the Big Bear Lake intrusive suite in the San Bernardino Mountains and similar sheeted rocks recovered in the Cajon Pass Deep Scientific Drillhole. Zircon U-Pb geochronology of 12 samples via secondary ionization mass spectrometry (SIMS) (six from the Cadiz Valley batholith and six from the Cajon Pass Deep Scientific Drillhole) indicates that all Cretaceous igneous units investigated were intruded between 83 and 74 Ma, and Cajon Pass samples include a Jurassic age component. A compilation of new and published SIMS geochronological data demonstrates that voluminous magmatism in the Eastern Transverse Ranges and central Mojave Desert was continuous throughout the period suggested for the intersection and flat-slab subduction of the Shatsky Rise conjugate deep into the interior of western North America. Whole-rock major-element, trace-element, and isotope geochemistry data from samples from a suite of 106 igneous rocks represent the breadth of Late Cretaceous units in the transect. Geochemistry indicates an origin in a subduction environment and intrusion into a crust thick enough to generate residual garnet. The lack of significant deflections of compositional characteristics and isotopic ratios in igneous products through space and time argues against a delamination event prior to 74 Ma. We argue that Late Cretaceous plutonism from the Eastern Transverse Ranges to the central Mojave Desert represents subduction zone arc magmatism that persisted until ca. 74 Ma. This interpretation is inconsistent with the proposed timing of the docking of the Shatsky Rise conjugate with the margin of western North America, particularly models in which the leading edge of the Shatsky Rise was beneath Wyoming at 74 Ma. Alternatively, the timing of cessation of plutonism precedes the timing of the passage of the Hess Rise conjugate beneath western North America at ca. 70–65 Ma. The presence, geochemical composition, and age of arc products in the Eastern Transverse Ranges and central Mojave Desert region must be accounted for in any tectonic model of the transition from Sevier to Laramide orogenesis.

show abstract

Section: Tectonic Settingsupporting

confidence: 89%

Section: Tectonic Settingsupporting

confidence: 52%

Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Renewed uplift of the Mogollon Highlands may have continued after the Jurassic, including during the Laramide orogenic event (ca. 80-40 Ma) (Chapman et al, 2019;Gastil et al, 1992;Karlstrom et al, 2020), but later periods of uplift are not related to the deposition of the Morrison Formation, the sub-Cretaceous disconformity, or the sub-Dakota unconformity.…”

Section: Mogollon Highlands and Bisbee Rift Systemmentioning

confidence: 88%

Beveling the Colorado Plateau: Early Mesozoic Rift‐Related Flexure Explains Erosion and Anomalous Deposition in the Southern Cordilleran Foreland Basin

Chapman

DeCelles

2021

Tectonics

View full text Add to dashboard Cite

show abstract

“…This petrogenetic environment is analogous to the Sierra Nevada Mountain range of California, where subduction-related granitic magmatism necessitates a cumulate root of arclogite composition (Lee et al, 2006). In the other hypothesis, Axen et al (2018) and A. D. Chapman et al (2020) propose that the arclogites are materials originally from the Sierran arc root lithosphere that were "bulldozed" inboard during Farallon flat slab subduction. Despite the discrepancy in mode of emplacement, both hypotheses state that these arclogites represent an arc root that formed during the Laramide orogeny which persisted in Arizona prior to delamination.…”

Section: Arizona Arclogite Xenolithsmentioning

confidence: 97%

Evolution of Microstructural Heterogeneity in the Deep Arc Lithosphere During Delamination

2023

View full text Add to dashboard Cite

The microstructural properties of deep arc cumulates (arclogites) are poorly understood, but are essential in gaining a comprehensive picture of the rheology of continental lithosphere. Here, we analyze 16 arclogite xenoliths, comprising a low MgO and a high MgO suite, from Arizona, USA using electron backscatter diffraction to map microstructures, clinopyroxene shape preferred orientations (SPO), and clinopyroxene crystallographic preferred orientations (CPO). The lower pressure (∼1 GPa) low MgO arclogites show a variety of different clinopyroxene fabrics (S, L, and LS‐type), whereas the high pressure (>2 GPa) high MgO arclogites show predominantly LS‐type fabrics. Furthermore, clinopyroxenes in low MgO arclogites all show a pronounced correspondence between the long axis of their grain shape ellipsoids with the [001] crystal direction, indicating an SPO control on the CPO. In contrast, high MgO arclogite clinopyroxenes lack such a correspondence. We propose that both arclogite types originated as igneous cumulates, consistent with previous studies, but that the high MgO suite experienced substantial recrystallization which diminished the original igneous SPO‐induced CPO. Using strain rates appropriate for arc settings, we calculate a strength profile for the lithosphere and argue that the deepest arclogite textures are consistent with lithospheric foundering through ductile deformation under high shear strain (10−14–10−12 s−1). Our study shows that there is a high degree of shear strain localization in deep arc roots while shallower portions are relatively undeformed.

show abstract

Fate of the lower lithosphere during shallow-angle subduction: The Laramide example

Abstract: Continental arc lower crust and underlying mantle wedge assemblages native to the Mojave Desert were dislodged, transported eastward during Laramide shallow-angle subduction, and attached to the base of the Colorado Plateau transition zone (central Arizona, USA) and further inboard. We

Cited by 27 publications

References 47 publications

Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

Beveling the Colorado Plateau: Early Mesozoic Rift‐Related Flexure Explains Erosion and Anomalous Deposition in the Southern Cordilleran Foreland Basin

Evolution of Microstructural Heterogeneity in the Deep Arc Lithosphere During Delamination

Contact Info

Product

Resources

About