Renee Tamblyn

Universität Bern | UniBe · Institute of Geological Sciences

The coupling behaviour of H+ and trace elements in rutile has been studied using in situ polarised Fourier transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrom- etry (LA–ICP–MS) analysis. H2O contents in rutile can be precisely and accurately quantified from polarised FTIR measurements on single grains...

The preserved Archean continental crust is dominantly comprised of tonalite-trondhjemite-granodiorite (TTG) suites associated with less abundant low-grade greenstone belts. The exact processes that form TTGs, as well as the source rock they are derived from, are difficult to constrain from the sparse Archean geological record. However, studies show...

Garnet is a fundamental expression of metamorphism and one of the most important minerals used to constrain the thermal conditions of the crust. We used innovative in situ laser-ablation ICP-MS/MS Lu-Hf geochronology to demonstrate that garnet in metapelitic rocks enclosing Cambrian eclogite in southern Australia formed during Laurentian Mesoproter...

In this study, data from garnet‐kyanite metapelites in ultrahigh‐pressure (UHP) domains of the Western Gneiss Region (WGR), Norway is presented. U–Pb geochronology and trace element compositions in zircon, monazite, apatite, rutile and garnet were acquired, and pressure–temperature (P–T) conditions were calculated using mineral equilibria forward m...

The development of in-situ laser ablation Lu–Hf geochronology of apatite, xenotime and garnet has opened avenues to quickly and directly date geological processes. We demonstrate the first use of campaign-style in-situ Lu–Hf geochronology of garnet across the high- to ultrahigh-pressure Western Gneiss Region in Norway. Mafic eclogites from this reg...

Igneous and metamorphic rocks contain the mineralogical and geochemical record of thermally driven processes on Earth. The generally accepted thermal budget of the mantle indicates a steady cooling trend since the Archean. The geological record, however, indicates this simple cooling model may not hold true. Subduction-related eclogites substantial...

LuHf geochronology is a powerful method to constrain the temporal evolution of geological systems. Traditional application of this dating method requires time-consuming chemical separation of the parent (¹⁷⁶Lu) and daughter (¹⁷⁶Hf) isotopes that is commonly accompanied by loss of textural context of the analysed minerals. In contrast, In-situ (lase...

In cases where metamorphic rocks preserve superimposed mineral assemblages, recorded pressure-temperature (P–T) histories are often difficult to differentiate. Here, we use the recently developed in-situ laser ablation ICP–MS/MS Lu–Hf geochronology method (see companion abstract, Simpson et al., session 6d) to demonstrate that garnets from crustal...

The ca. 2 Ga retrogressed eclogites in the Usagaran Belt in central Tanzania are among the oldest documented eclogites in the world. As such, they have been used to pinpoint the thermal conditions of the onset of modern style subduction on Earth. Two samples of retrogressed mafic eclogite have been interrogated to reconstruct the metamorphic histor...

Translating burial and exhumation histories from the petrological and geochronological record of high-pressure assemblages in subduction channels is key to understanding subduction channel processes. Convective return flow, either serpentinite or sediment hosted, has been suggested as a potential mechanism to retrieve rocks from significant depths...

One of the first appearances of eclogite-facies mineral assemblages in the geological record occurs in the c. 2000 Ma Palaeoproterozoic Usagaran Belt in central Tanzania, where the extended margin of the Tanzanian Craton is interpreted to have been subducted. Mafic rocks are interpreted to have contained the mineral assemblage garnet + omphacite +...

Lawsonite eclogite and garnet blueschist occur as metre‐scale blocks within serpentinite mélange in the southern New England Orogen in eastern Australia. These high‐pressure fragments are the products of early Palaeozoic subduction of the palaeo‐Pacific plate beneath East Gondwana. Lu–Hf, Sm–Nd and U–Pb geochronological data from Port Macquarie sho...

From ca. 50 Ma to present, the western Pacific plate has been subducting under the Philippine Sea plate, forming the oceanic Izu-Bonin-Mariana (IBM) subduction system. It is the only known location where subduction zone products are presently being transported to the surface by serpentinite-mud volcanoes. A large serpentine mud “volcano” forms the...

One of the first appearances of eclogite-facies assemblages in the geological record is documented in the Palaeo-proterozoic Usagaran Belt in central Tanzania, where the extended margin of the Tanzanian Craton is interpreted to have been subducted (Moller et al., 1995; Reddy et al., 2003). The c. 2000 Ma eclogites contained the assemblage garnet +...

Ultrahigh temperature (UHT) granulites in the Eastern Ghats Province (EGP) have a complex P–T–t history. We review the P–T histories of UHT metamorphism in the EGP and use that as a framework for investigating the P–T–t history of Mg–Al-rich granulites from Anakapalle, with the express purpose of trying to reconcile the down pressure-dominated P–T...

High-pressure rocks occur throughout the southern New England Fold Belt in New South Wales as exotic blocks enveloped within serpentinite-melange that sampled the deeper parts of the palaeosubduction-accretion system along the eastern margin of Gondwana. Ar-Ar and K-Ar geochronology from white mica in blueschists from Pigna Barney, Glenrock Station...