Peter Luffi

Peter Luffi
Roman Academy Institute of Geodynamics

PhD

About

59
Publications
10,931
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2,625
Citations
Citations since 2016
6 Research Items
1566 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250

Publications

Publications (59)
Article
Full-text available
Convergent plate boundaries are key sites for continental crustal formation and recycling. Quantifying the evolution of crustal thickness and paleoelevation along ancient convergent margins represents a major goal in orogenic system analyses. Chemical and in some cases isotopic compositions of igneous rocks formed in modern supra‐subduction arcs an...
Data
A database containing previously published geochronologic, geochemical, and isotopic data on Mesozoic to Quaternary igneous rocks from the Carpathian-Pannonian region are presented. Georeferenced data making up this database belong mostly to five magmatic arcs: (1) the south Apuseni Jurassic island arc/backarc province, (2) a small volume mid Creta...
Article
Temporal trends in granitoid chemistry and thermometry constrain major global changes in magmatism, tectonism or crustal thickness in the continents. Our study relies on zircon geochronology and trace element geochemistry on four new detrital rocks (two modern sediments and two Archean metasedimentary rocks) and a global compilation of published si...
Article
Full-text available
The Pleistocene (1.65Ma) Crystal Knob volcanic neck in the California Coast Ranges is an olivine‐plagioclase phyric basalt containing dunite and spinel peridotite xenoliths. Crystal Knob erupted through the Nacimiento belt of the Franciscan complex and adjacent to Salinian crystalline nappes. Its xenoliths sample the mantle lithosphere beneath the...
Article
Rare ultrahigh-temperature–(near)ultrahigh-pressure (UHT–near-UHP) crustal xenoliths erupted at 11 Ma in the Pamir Mountains, southeastern Tajikistan, preserve a compositional and thermal record at mantle depths of crustal material subducted beneath the largest collisional orogen on Earth. A combination of oxygen-isotope thermometry, major-element...
Article
Full-text available
Arc magmas are important building blocks of the continental crust. Because many arc lavas are oxidized, continent formation is thought to be associated with oxidizing conditions. On the basis of copper’s (Cu’s) affinity for reduced sulfur phases, we tracked the redox state of arc magmas from mantle source to emplacement in the crust. Primary arc an...
Article
Full-text available
Thickening of arc lithosphere influences the extent of magmatic differentiation and is thereby important for the evolution of juvenile arcs into mature continental crust. Here, we use mantle xenoliths from the late Mesozoic Sierra Nevada continental arc in California (USA) to constrain the pressure, temperature, and compositional evolution of the d...
Article
Several studies using conventional TIMS instrumentation have shown that U-Pb geochronology on sedimentary calcites can reliably return geologically useful information because of the high U/Pb of some carbonates. Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) has the potential of providing an alternative to laborious TIMS technique...
Article
The San Emigdio and related Pelona, Orocopia, Rand and Sierra de Salinas schists of southern California were underplated beneath the southern Sierra Nevada batholith and adjacent southern California batholith along a shallow segment of the subducting Farallon plate in Late Cretaceous to early Tertiary time. These subduction accretion assemblages re...
Article
Full-text available
Continents, especially their Archean cores, are underlain by thick thermal boundary layers that have been largely isolated from the convecting mantle over billion-year timescales, far exceeding the life span of oceanic thermal boundary layers. This longevity is promoted by the fact that continents are underlain by highly melt-depleted peridotites,...
Article
Elemental recycling during subduction has played a key role in the geochemical evolution of the Earth, with recycling efficiencies as high as >75-80% for some elements (e.g., Th). Tracking the fluids and/or melts responsible for recycling, and understanding the P-T conditions at which recycling occurs, are more difficult as access to these conditio...
Article
Basalt compositions reflect physico-chemical factors controlling magma generation, transport, and emplacement, and it is widely thought that, if chemical variables are known (e.g. Mgnd fO (super 2) in source peridotites) or properly corrected for (e.g. olivine fractionation), then the P-T conditions of mantle melting can be reasonably constrained....
Article
Thickening of continental arc lithosphere, either by underplating, magmatic inflation, or other tectonic processes, is an important stage in the maturation of primitive island arcs into Phanerozoic continental crust. The Sierra Nevada continental arc is one example of a mature arc that has experienced significant thickening and recent orogenic coll...
Article
Fluids and melts released from subducted slabs are transferred into the overlying mantle wedge, facilitating the recycling of incompatible elements from subducting lithosphere into arc crust. Thus, these fluids and melts play a major role in controlling the geochemical evolution of Earth. Numerous studies have demonstrated a correlation between ele...
Article
Melt-rock reaction in the lithosphere is, as suggested by textural observations and compositional data, a ubiquitous phenomenon capable of generating locally diverse peridotite series, such as those observed at oceanic spreading centers and transform faults, and may represent an important mechanism of creating compositional diversity in MORBs [1]....
Article
MELTS [1] and pMELTS [2] are widely used for modeling hydrous magma differentiation and water-saturated mantle melting, respectively. In pHMELTS [3] the water species can partition into melt, pure vapor, and hydrous or nominally anhydrous minerals so that phase relations for water-undersaturated systems may also be constructed. Adiabat_1ph is a tex...
Article
Full-text available
Many arc lavas are more oxidized than mid-ocean-ridge basalts and subduction introduces oxidized components into the mantle. As a consequence, the sub-arc mantle wedge is widely believed to be oxidized. The Fe oxidation state of sub-arc mantle is, however, difficult to determine directly, and debate persists as to whether this oxidation is intrinsi...
Conference Paper
The San Emigdio and related Pelona, Orocopia, Rand, and Sierra de Salinas schists of Southern California were underplated beneath the southern Sierra Nevada batholith and adjacent southern California batholith along a shallow segment of the subducting Farallon plate in Late Cretaceous – early Tertiary time. These subduction accretion assemblages re...
Article
Full-text available
Except for the first 50-100 million years or so of the Earth's history, when most of the mantle may have been subjected to melting, the differentiation of Earth's silicate mantle has been controlled by solid-state convection. As the mantle upwells and decompresses across its solidus, it partially melts. These low-density melts rise to the surface a...
Article
Retrograde eclogites (ranging from unaltered eclogite to retrograde blueschist and greenschist mantling the eclogite boulders) from Ring Mountain on the Tiburon Peninsula, near San Francisco, California, were examined for whole-rock major and trace elements to assess protolith compositions and the geochemical signature of fluids associated with ret...
Article
Full-text available
Basaltic magmatism is a common feature of dynamically active terrestrial planets. The compositions of basalts reflect the temperatures and pressures of magma generation, providing windows into a planet's thermal state. Here, we present new thermobarometers based on magma Si and Mg contents to estimate the pressures and temperatures of basaltic magm...
Article
Low-angle subduction of oceanic lithosphere may be an important process in modifying continental lithosphere. A classic example is the underthrusting of the Farallon plate beneath North America during the Laramide orogeny. To assess the relevance of this process to the evolution and composition of continental lithosphere, the mantle stratigraphy be...
Article
New thermobarometers are presented that can estimate T-P of magma generation on Earth, Mars and other planetary bodies, providing constraints on lithosphere thickness and planetary thermal state (emphasis will be on Mars).
Article
Some hypotheses regarding continental crust formation and modification in magmatic arc settings involve mechanisms such as underplating by basaltic recharge, intracrustal intrusion and crustal inflation, and tectonic thickening. Knowledge of the P-T history may help to evaluate whether these mechanisms indeed play significant roles in continental a...
Article
The mantle lithosphere formed at mid-ocean ridges (MORML) is the residue left after the extraction of basaltic crust from the upwelling asthenospheric mantle. Abyssal peridotites and sub-Moho sections of ophiolites limit insight into its shallowest portions, thus the MORML's bulk composition and scales of internal heterogeneity remain poorly constr...
Article
Full-text available
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of B and Li in serpentinized peridotites from the Feather River Ophiolite (California) indicates that B is enriched in serpentine minerals compared to the whole-rock and less altered olivine grains, while Li in serpentine is depleted or comparable to whole-rock Li. The...
Article
Full-text available
Geodetic data, interpreted in light of seismic imaging, seismicity, xenolith studies, and the late Quaternary geologic history of the northern Great Basin, suggest that a subcontinental-scale extensional detachment is localized near the Moho. To first order, seismic yielding in the upper crust at any given latitude in this region occurs via an M7 e...
Conference Paper
Full-text available
The Earth's mantle differentiates mainly by decompression partial melting induced by solid-state convection. Owing to their low densities, these magmas rise to the surface and drive the formation of oceanic and continental crusts. Because many trace elements, including the heat-producing elements, are partitioned into liquids, the extraction of mel...
Article
Cratons form the cores of continents and were formed within a narrow window of time (2.5-3.2 Gy ago), the majority having remained stable ever since. Petrologic evidence suggests that the thick mantle roots underlying cratons were built by underthrusting of oceanic and arc lithosphere, but paradoxically this requires that the building blocks of cra...
Article
The Talkeetna arc is one of two intraoceanic arcs where much of the section from the upper mantle through the volcanic carapace is well exposed. We reconstruct the vertical section of the Talkeetna arc by determining the (re) crystallization pressures at various structural levels. The thermobarometry shows that the tonalites and quartz diorites int...
Article
Full-text available
The Talkeetna arc is one of two intraoceanic arcs where much of the section from the upper mantle through the volcanic carapace is well exposed. We reconstruct the vertical section of the Talkeetna arc by determining the (re)crystallization pressures at various structural levels. The thermobarometry shows that the tonalites and quartz diorites intr...
Article
Intensive study of the Rand schist (hereafter referred to as the "schist") of southern California demonstrate convincingly that it formed in the Late Cretaceous by subduction of Cordilleran eogeoclinal detritus along a shallow dipping segment of the Farallon plate. Comparatively less is understood regarding the exhumation history of the schist. Rec...
Article
Basaltic magmatism is a common feature of dynamically active terrestrial planets. Because the compositions of basalts reflect temperatures and pressures of magma generation, these basalts are windows into a planet's thermal state. Here, we present thermobarometric results based on Si-barometry and Mg-thermometry to estimate the pressures and temper...
Article
The correct evaluation of the maximum degree of depletion experienced by peridotites and the physical conditions at which their melting occurred is critical to constraining the origin of sub-continental lithospheric mantle (SCLM). For example, whole-rock (WR) MgO-Al2O3 and MgO-Yb trends observed in various peridotites suites can be used to retrieve...
Article
Intensive study of the Rand schist (hereafter referred to as the "schist") of southern California demonstrate convincingly that it formed in the Late Cretaceous by subduction of Cordilleran eogeoclinal detritus along a shallow dipping segment of the Farallon plate. Comparatively little is known about the exhumation history of the schist. Recent the...
Article
Cratons form the cores of continents and were formed within a narrow window of time (2.5-3.2 Gy ago), the majority having remained stable ever since. Petrologic evidence suggests that the thick mantle roots underlying many cratons might have been built by lithospheric stacking, but paradoxically this requires that the building blocks of cratons are...
Conference Paper
It is well-known that the continental crust is too silicic to have been derived directly as a melt from the mantle, so in order to balance the crust's composition with respect to basalt a missing mafic reservoir is needed. Thus, a multi-stage scenario is required to generate continental crust. First, basalt is extracted from the mantle. The basalt...
Article
Several lines of evidence indicate that much of the Laramide and post-Laramie extension of the Mojave-Salinia lithosphere occurred atop the flat Farallon oceanic slab, possibly as it began to rollback to a steeper subduction trajectory. Simple mass balance that ignores erosion suggests that the ~200% extension should have been accompanied by about...
Article
Intergranular element transfer-controlled garnet growth is a recently suggested explanation for high-Ca annuli in chemically zoned garnets from a wide range of bulk compositions. However, little is known regarding the source of requisite elemental fluxes responsible for such Ca disequilibrium during garnet growth. The Rand schist of the San Emigdio...
Article
Xenoliths of subducted crustal origin hosted by Miocene ultrapotassic igneous rocks in the southern Pamir provide important new information regarding the geological processes accompanying tectonism during the Indo-Eurasian collision. Four types have been studied: sanidine eclogites (omphacite, garnet, sanidine, quartz, biotite, kyanite), felsic gra...
Article
Full-text available
Garnet porphyroblasts of impressive size and/or abundance spatially associated with trondhjemitic leucosomes are known from a variety of migmatites worldwide [e.g. 1-4], and have frequently been interpreted as peritectic products of dehydration melting due to P-T variations controlled by regional-scale tectonothermal processes. However, to produce...
Article
The Pamir mountains are an outstanding example of extreme crustal shortening during continental collision that may have been accommodated by formation of a thick crust-much thicker than is currently thought-and/or by continental subduction. We present new petrologic data and radiometric ages from xenoliths in Miocene volcanic rocks in the southeast...
Article
Xenoliths of subducted crustal origin hosted by Miocene ultrapotassic igneous rocks in the southern Pamir provide important new information regarding the geological processes accompanying tectonism during the Indo-Eurasian collision. Four types have been studied: sanidine eclogites (omphacite, garnet, sanidine, quartz, biotite, kyanite), felsic gra...

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