Neal J. McNaughton

Bio: Neal J. McNaughton is an academic researcher from Curtin University. The author has contributed to research in topics: Zircon & Geochronology. The author has an hindex of 63, co-authored 262 publications receiving 12757 citations. Previous affiliations of Neal J. McNaughton include University of Queensland & University of Western Australia.

First evidence of >3.2 Ga continental crust in the Yangtze craton of south China and its implications for Archean crustal evolution and Phanerozoic tectonics

Abstract: Ion microprobe (SHRIMP II) U-Pb zircon analyses reveal trondhjemitic magmatism at 2.90–2.95 Ga in the Kongling area of the Yangtze craton, south China, about 150 km south of the Permian-Triassic Qinling-Dabie-Sulu orogenic belt. Detrital zircons from nearby Archean metapelites are 2.87–3.28 Ga, and the rocks have Sm-Nd depleted mantle model ages of 3.07–3.21 Ga. The new data reveal, for the first time, >3.2 Ga sialic crust in the Yangtze craton, part of which predates that of the adjacent southern North China craton. Both trondhjemites and metapelites contain ca. 2.75 Ga high-grade metamorphic zircons, and ca. 1.9 Ga zircons, related to intrusion of the Quanqitang K-feldspar granite into the Archean basement. Many zircons also underwent Pb loss ca. 1.0 Ga during the Jinning orogeny, when the Cathysian block accreted to the Yangtze craton. The new data support correlation of part of the Korean Peninsula with the Yangtze craton along the eastern extension of the Qinling-Dabie-Sulu orogenic belt.

West African provenance for Saxo-Thuringia (Bohemian Massif): Did Armorica ever leave pre-Pangean Gondwana? – U/Pb-SHRIMP zircon evidence and the Nd-isotopic record

Abstract: Neoproterozoic rocks in the Saxo-Thuringian part of Armorica formed in an active margin setting and were overprinted during Cadomian orogenic processes at the northern margin of Gondwana. The Early Palaeozoic overstep sequence in Saxo-Thuringia was deposited in a Cambro-Ordovician rift setting that reflects the separation of Avalonia and other terranes from the Gondwana mainland. Upper Ordovician and Silurian to Early Carboniferous shelf sediments of Saxo-Thuringia were deposited at the southern passive margin of the Rheic Ocean. SHRIMP U/Pb geochronology on detrital and inherited zircon grains from pre-Variscan basement rocks of the northern part of the Bohemian Massif (Saxo-Thuringia, Germany) demonstrates a distinct West African provenance for sediments and magmatic rocks in this part of peri-Gondwana. Nd-isotope data of Late Neoproterozoic to Early Carboniferous sedimentary rocks show no change in sediment provenance from the Neoproterozoic to the Lower Carboniferous, which implies that Saxo-Thuringia did not leave its West African source before the Variscan Orogeny leading to the Lower Carboniferous configuration of Pangea. Hence, large parts of the pre-Variscan basement of Western and Central Europe often referred to as Armorica or Armorican Terrane Assemblage may have remained with Africa in pre-Pangean time, which makes Armorica a remnant of a “Greater Africa” in Gondwanan Europe. The separation of Armorica from the Gondwana mainland and a long drift during the Palaeozoic is not supported by the presented data.

Regression Diagnostics: Identifying Influential Data and Sources of Collinearity

Abstract: 1. Introduction and Overview. 2. Detecting Influential Observations and Outliers. 3. Detecting and Assessing Collinearity. 4. Applications and Remedies. 5. Research Issues and Directions for Extensions. Bibliography. Author Index. Subject Index.

The Composition of Zircon and Igneous and Metamorphic Petrogenesis

Abstract: Zircon is the main mineral in the majority of igneous and metamorphic rocks with Zr as an essential structural constituent. It is a host for significant fractions of the whole-rock abundance of U, Th, Hf, and the REE (Sawka 1988, Bea 1996, O’Hara et al. 2001). These elements are important geochemically as process indicators or parent isotopes for age determination. The importance of zircon in crustal evolution studies is underscored by its predominant use in U-Th-Pb geochronology and investigations of the temporal evolution of both the crust and lithospheric mantle. In the past decade an increasing interest in the composition of zircon, trace-elements in particular, has been motivated by the effort to better constrain in situ microprobe-acquired isotopic ages. Electron-beam compositional imaging and isotope-ratio measurement by in situ beam techniques—and the micrometer-scale spatial resolution that is possible—has revealed in many cases that single zircon crystals contain a record of multiple geologic events. Such events can either be zircon-consuming, alteration, or zircon-forming and may be separated in time by millions or billions of years. In many cases, calculated zircon isotopic ages do not coincide with ages of geologic events determined from other minerals or from whole-rock analysis. To interpret the geologic validity and significance of multiple ages, and ages unsupported by independent analysis of other isotopic systems, has been the impetus for most past investigations of zircon composition. Some recent compositional investigations of zircon have not been directly related to geochronology, but to the ability of zircon to influence or record petrogenetic processes in igneous and metamorphic systems. Sedimentary rocks may also contain a significant fraction of zircon. Although authigenic zircon has been reported (Saxena 1966, Baruah et al. 1995, Hower et al. 1999), it appears to be very rare and may in fact be related to …

Atlas of Zircon Textures

Abstract: The mineral zircon is extremely variable both in terms of external morphology and internal textures. These features reflect the geologic history of the mineral, especially the relevant episode(s) of magmatic or metamorphic crystallization (and recrystallization), strain imposed both by external forces and by internal volume expansion caused by metamictization, and chemical alteration. The paper presents a selection of both the most typical, but also of the less common, features seen in zircon, categorized according to the different geological processes responsible for their formation. The atlas is intended as a general guide for the interpretation of zircon characteristics, and of related isotopic data. Zircon has become one of the most widely used minerals for the extraction of information on the prehistory and genesis of magmatic, metamorphic and sedimentary rocks. Much of the geological usefulness of zircon stems from its suitability as a geochronometer based on the decay of U (and Th) to Pb, but in addition it is also the major host of the radiogenic isotopic tracer Hf, and it is used to determine oxygen isotopic compositions and REE and other trace element abundances, all of which yield useful clues concerning the history of the host rock, and in some case, the parent rock in which the precursor zircon crystallized. One of the major advantages of zircon is its ability to survive magmatic, metamorphic and erosional processes that destroy most other common minerals. Zircon-forming events tend to be preserved as distinct structural entities on a pre-existing zircon grain. Because of this ability, quite commonly zircon consists of distinct segments, each preserving a particular period of zircon-formation (or consumption). A long experience and modern instrumentation and techniques have provided the “zircon community” the means to image and interpret preserved textures, and hence to decipher the history and evolution of a rock. One …