Results 61 to 70 of about 5,022,556 (217)

Provenance study of the Xining loess in the Northeastern Tibetan Plateau, China

open access: yesDizhi lixue xuebao, 2022
Single-grain U-Pb dating of detrital zircons is regarded as an efficient and effective technique to differentiate the contribution of discrete sources.
LI Zongyao   +4 more
doaj   +1 more source

Heterogeneous Exhumation Mechanisms in Neoproterozoic Collisional Metamorphism: P–T Constraints From Pelotas and Punta del Este Terranes, Southern Brazil and Uruguay

open access: yesGeological Journal, EarlyView.
Petrography, thermobarometry, and pseudosection modelling reveal peak metamorphic conditions of 3–7.5 kbar and 520°C–800°C in Tonian‐Cryogenian orthogneisses of the Dom Feliciano Belt. Metamorphic field gradients of 27°C/km–39°C/km and variable exhumation mechanisms support correlation of these units as remnants of a Himalayan‐type Piratini Orogeny ...
Thaiane Niederauer‐Santos   +6 more
wiley   +1 more source

Extensional faulting on Tinos island, Aegean sea, Greece: How many detachments? [PDF]

open access: yes, 2007
Zircon and apatite fission track (ZFT and AFT) and (U-Th)/He, 40Ar/39Ar hornblende, and U-Pb zircon ages from the granites of Tinos Island in the Aegean Sea, Greece, suggest, together with published ZFT data, that there are three extensional detachments ...
Maurice Brunel   +28 more
core   +1 more source

Miocene to Quaternary Tectonostratigraphic Evolution of the Northern Section of the Burdur‐Fethiye Shear Zone, South‐Western Türkiye

open access: yesGeological Journal, EarlyView.
New zircon ages reveal that lacustrine sedimentation initiated in the Late Miocene (Messinian), revising earlier Pliocene age assignments. The study results support the interpretation of the northern BFSZ as a broad left‐lateral transtensional shear zone rather than a discrete sinistral fault or simple extensional graben array.
İrem Elitez   +3 more
wiley   +1 more source

A novel sample pre-screening methodology for accurate in situ U-Pb dating of zircon crystals

open access: yesHeliyon
Internal inhomogeneity of the zircon crystals makes it difficult to date succedent geological processes. To overcome this limitation, a four-step pre-examination method is suggested before LA-ICP-MS based in situ U-Pb age determination of zircon crystals:
Annamária Kis
doaj   +1 more source

Glass from Teniky (Madagascar): Geochemical Evidence for Multiple Production Systems and Long‐Distance Exchange in the Mediaeval Indian Ocean

open access: yesArchaeometry, EarlyView.
ABSTRACT The inland rock‐cut site of Teniky, located in the Isalo massif of southern Madagascar, represents an exceptional archaeological context recently dated to the 11th–12th centuries ad, corresponding to the early phases of settlement on the island.
Jean Rodier   +2 more
wiley   +1 more source

Appraisal of Six Natural Mica Reference Materials for In Situ Rb‐Sr Geochronology

open access: yesGeostandards and Geoanalytical Research, EarlyView.
Key Points Evaluated six natural mica reference materials for in situ LA‐ICP‐MS/MS Rb‐Sr geochronology using geochemical, microstructural and isotopic characterisation. Identified robust primary reference materials: Mount Dromedary biotite (99.37 Ma) and Mica‐Fe biotite (307.75 Ma). La Posta biotite and Högsbo muscovite are suitable secondary reference
Hugo K.H. Olierook   +38 more
wiley   +1 more source

Discovery of mafic impact melt in the center of the Vredefort dome:archetype for continental residua of early Earth cratering? [PDF]

open access: yes, 2014
Melting by impact heating is thought to have been a significant process in the modification of early planetary crusts; however, crustally derived melt bodies in ancient terrestrial crust are frequently presumed to be absent due to erosion.
Barker, I. R.   +6 more
core   +1 more source

SC‐550: A Sintered Calcite Reference Material for In Situ U‐Pb Geochronology

open access: yesGeostandards and Geoanalytical Research, EarlyView.
Key Points New calcite reference material (SC‐550) produced by high‐temperature and high‐pressure sintering of nano‐particulate powder from a microbial limestone. Homogeneous U content (2.3 ± 0.4 μg g‐1) and U‐Pb isotope ratios (< 0.6% RSD for 207Pb/206Pb; < 3% RSD for 238U/206Pb).
Lorenzo Tavazzani   +7 more
wiley   +1 more source

K-feldspar sand-grain provenance in the Triassic, west of Shetland : distinguishing first-cycle and recycled sediment sources? [PDF]

open access: yes, 2009
Sandstone provenance studies can help constrain palaeogeographic reconstructions and ancient drainage system scales and pathways. However, these insights can be obscured by difficulties in geochemically distinguishing or adequately characterising ...
Daly, J. Stephen   +9 more
core   +1 more source

Home - About - Disclaimer - Privacy