Franciscan subduction off to a slow start: evidence from high-precision Lu–Hf garnet ages on high grade-blocks

Anczkiewicz, Robert; Platt, J. P.; Thirlwall, M. F.; Wakabayashi, John

doi:10.1016/j.epsl.2004.06.003

Cited by 200 publications

(186 citation statements)

References 37 publications

Supporting

Mentioning

175

Contrasting

Unclassified

Order By: Relevance

“…The analyses were made with a Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS) Neptune. The samples were digested in three steps: firstly, with HF: HNO 3 , secondly, with HNO 3 and finally, with HCl and HF, following the procedure described by Anczkiewicz et al (2004) and Anczkiewicz & Thirlwall (2003). The samples were then dissolved in HCl for loading on cation exchange columns with AG50Wx8 resin (Anczkiewicz et al 2004).…”

Section: Methodsmentioning

confidence: 99%

“…The samples were digested in three steps: firstly, with HF: HNO 3 , secondly, with HNO 3 and finally, with HCl and HF, following the procedure described by Anczkiewicz et al (2004) and Anczkiewicz & Thirlwall (2003). The samples were then dissolved in HCl for loading on cation exchange columns with AG50Wx8 resin (Anczkiewicz et al 2004). Final separation of Sr was performed by Sr-spec resin (Peryt et al 2010) and Nd by Ln-spec resin (Anczkiewicz & Thirlwall 2003 (Jacobsen & Wasserburg 1980;DePaolo 1981).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

View full text Add to dashboard Cite

The paper presents new major and trace element and first Sr-Nd isotope data from selected lavas among the Permian basaltic andesite and basalts of the Hronicum Unit and the dolerite dykes cutting mainly the Pennsylvanian strata. The basic rocks are characterized by small to moderate mg # numbers (30 to 54) and high SiO 2 contents (51-57 wt. %). Low values of TiO 2 (1.07-1.76 wt. %) span the low-Ti basalts. Ti/Y ratios in the dolerite dykes as well as the basaltic andesite and basalt of the 1 st eruption phase are close to the recommended boundary 500 between high-Ti and low-Ti basalts. Ti/Y value from the 2 nd eruption phase basalt is higher and inclined to the high-Ti basalts. In spite of this fact, in all studied Hronicum basic rocks Fe 2 O 3 * is lower than 12 wt. % and Nb/La ratios (0.3-0.6) are low, which is more characteristic of low-Ti basalts. The basic rocks are characterized by Nb/La ratios (0.56 to 0.33), and negative correlations between Nb/La and SiO 2 , which point to crustal assimilation and fraction crystallization. The intercept for Sr evolution lines of the 1 st intrusive phase basalt is closest to the expected extrusions age (about 290 Ma) with an initial 87 Sr/ 86 Sr ratio of about 0.7054. Small differences in calculated values I Sr document a partial Sr isotopic heterogeneity source (0.70435-0.70566), or possible contamination of the original magma by crustal material. For Nd analyses of the three samples, the calculated values εCHUR (285 Ma) are positive (from 1.75 to 3.97) for all samples with only subtle variation. Chemical and isotopic data permit us to assume that the parental magma for the Hronicum basic rocks was generated from an enriched heterogeneous source in the subcontinental lithospheric mantle.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

View full text Add to dashboard Cite

show abstract

“…The shaley me´lange contains chert, graywacke and basalt boudins, some of which are intensely recrystallized. Most of the coarse-grained, Late Jurassic (155 ± 5 Ma; Wakabayashi, 1999;Anczkiewicz et al, 2004;Saha et al, 2005) eclogite and amphibolite tectonic blocks occur in the Central belt; they represent exotic tectonic additions to the lower grade me´langes that make up in this terrane. Some inclusions are retrograded to blueschist-facies mineral assemblages (e.g.…”

Section: Structural-tectonic Relationshipsmentioning

confidence: 99%

Mesozoic transpression, transtension, subduction and metallogenesis in northern and central California

2008

View full text Add to dashboard Cite

Middle Paleozoic to Middle Jurassic terrane assemblies in the Klamaths and Sierran Foothills consist of mafic-ultramafic complexes + fine-grained terrigenous strata derived from previously accreted continental-margin belts. Sutured oceanic terranes reflect c. 230 Myr of margin-parallel slip involving chiefly transtension and transpression. Quartzofeldspathic clastic rocks and blueschists ± eclogites are very rare. Little devolatilization occurred at magmagenic depths; hence, coeval hydrothermal ore deposits and granitoids are uncommon. In contrast, nearly head-on Cretaceous subduction of the Farallon plate generated the massive Klamath-Sierra Nevada volcanicplutonic arc, reflecting dewatering of the eastward descending oceanic lithosphere in the magmagenic zone. Immature Great Valley forearc and Franciscan trench deposits shed from the arc record c. 70 Myr. of rapid crustal growth. Au-bearing solutions rising from magmagenic depths, exsolved from plutons, and expelled from heated wall rocks were mobilized attending arc construction. Precipitation of gold-bearing quartz veins

show abstract

“…High-pressure mafic tectonic inclusions formed in an oceanic transpression zone along an initially unrefrigerated, hot hanging wall (i.e., the mantle wedge), as evident from mineral parageneses that indicate counterclockwise P-T-time trajectories [Wakabayashi, 1999;Anczkiewicz et al, 2004]. Current vectors and the finegrained volcanogenic nature of clastic strata that make up the Mariposa-Galice sequences suggest their derivation from an emerging landward volcanic-plutonic arc [Bogen, 1984[Bogen, , 1985Gray, 2006].…”

Section: Plate Tectonic Implicationsmentioning

confidence: 99%

Guadalupe pluton–Mariposa Formation age relationships in the southern Sierran Foothills: Onset of Mesozoic subduction in northern California?

Ernst

Saleeby

Snow³

2009

J. Geophys. Res.

View full text Add to dashboard Cite

[1] We report a new 153 ± 2 Ma SIMS U-Pb date for zircons from the hypabyssal Guadalupe pluton which crosscuts and contact metamorphoses upper crustal Mariposa slates in the southern Sierra. A $950 m thick section of dark metashales lies below sandstones from which clastic zircons were analyzed at 152 ± 2 Ma. Assuming a compacted depositional rate of $120 m/Myr, accumulation of Mariposa volcanogenic sediments, which overlie previously stranded Middle Jurassic and older ophiolite + chertargillite belts in the Sierran Foothills, began no later than $160 Ma. Correlative Oxfordian-Kimmeridgian strata of the Galice Formation occupy a similar position in the Klamath Mountains. We speculate that the Late Jurassic was a time of transition from (1) a mid-Paleozoic-Middle Jurassic interval of mainly but not exclusively strike-slip and episodic docking of oceanic terranes; (2) to transpressive plate underflow, producing calcalkaline igneous arc rocks ± outboard blueschists at $170-150 Ma, whose erosion promoted accumulation of the Mariposa-Galice overlap strata; (3) continued transpressive underflow attending $200 km left-lateral displacement of the Klamath salient relative to the Sierran arc at $150-140 Ma and development of the apparent polar wander path cusps for North and South America; and (4) then nearly orthogonal mid and Late Cretaceous convergence commencing at $125-120 Ma, during reversal in tangential motion of the Pacific plate. After $120 Ma, nearly head-on subduction involving minor dextral transpression gave rise to voluminous continent-building juvenile and recycled magmas of the Sierran arc, providing the erosional debris to the Great Valley fore arc and Franciscan trench.

show abstract

Franciscan subduction off to a slow start: evidence from high-precision Lu–Hf garnet ages on high grade-blocks

Cited by 200 publications

References 37 publications

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Mesozoic transpression, transtension, subduction and metallogenesis in northern and central California

Guadalupe pluton–Mariposa Formation age relationships in the southern Sierran Foothills: Onset of Mesozoic subduction in northern California?

Contact Info

Product

Resources

About