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Zircon U-Pb-Hf constraints from Gongga Shan granites on young crustal melting in eastern Tibet

Geoscience Frontiers 2019年第3期10卷 885-894页

作者： Nick M.W.Roberts Michael P.Searle nerc Isotope Geosciences Laboratory British Geological Survey Environment Science Centre Department of Earth Sciences University of Oxford

The Gongga Shan batholith is a complex granitoid batholith on the eastern margin of the Tibetan Plateau with a long history of magmatism spanning from the Triassic to the Pliocene. Late Miocene-Pliocene units are the youngest exposed crustal melts within the entire Asian plate of the Tibetan ***, we present in-situ zircon Hf isotope constraints on their magmatic source, to aid the understanding of how these young melts were formed and how they were exhumed to the surface. Hf isotope signatures of Eocene to Pliocene zircon rims(ε_(Hf)(t)=-4 to +4), interpreted to have grown during localised crustal melting, are indicative of melting of a Neoproterozoic source region, equivalent to the nearby exposed Kangding Complex. Therefore, we suggest that Neoproterozoic crust underlies this region of the Songpan-Ganze terrane, and sourced the intrusive granites that form the Gongga Shan batholith. Localised young melting of Neoproterozoic lower or middle crust requires localised melt-fertile lithologies. We suggest that such melts may be equivalent to seismic and magnetotelluric low-velocity and high-conductivity zones or "bright spots" imaged across much of the Tibetan Plateau. The lack of widespread exposed melts this age is due either to the lack of melt-fertile rocks in the middle crust, the very low erosion level of the Tibetan plateau, or to a lack of mechanism for exhuming such melts. For Gongga Shan, where some melting is younger than nearby thermochronological ages of low temperature cooling, the exact process and timing of exhumation remains enigmatic, but their location away from the Xianshuihe fault precludes the fault acting as a conduit for the young melts. We suggest that underthrusting of dry granulites of the lower Indian crust(Archaean shield) this far northeast is a plausible mechanism to explain the uplift and exhumation of the eastern Tibetan Plateau.

关键词： Tibet Himalaya Hf isotopes Zircon Crustal melting

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The boring billion? - Lid tectonics, continental growth and environmental change associated with the Columbia supercontinent

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Geoscience Frontiers 2013年第6期4卷 681-691页

作者： Nick M.W.Roberts nerc Isotope Geosciences Laboratory British Geological SurveyKeyworthNottingham NG12 5GGUK

The evolution of Earth＇s biosphere,atmosphere and hydrosphere is tied to the formation of continental crust and its subsequent movements on tectonic *** supercontinent cycle posits that the continental crust is periodically amalgamated into a single landmass,subsequently breaking up and dispersing into various continental *** is possibly the first true supercontinent,it amalgamated during the 2.0-1.7 Ga period,and collisional orogenesis resulting from its formation peaked at 1.95-1.85 *** and palaeomagnetic evidence indicate that Columbia remained as a quasi-integral continental lid until at least 1.3 *** break-up attempts are evidenced by dyke swarms with a large temporal and spatial range; however,palaeomagnetic and geologic evidence suggest these attempts remained *** than dispersing into continental fragments,the Columbia supercontinent underwent only minor modifications to form the next supercontinent （Rodinia） at 1.1 -0.9 Ga; these included the transformation of external accretionary belts into the internal Grenville and equivalent collisional *** Columbia provides evidence for a form of ‘lid tectonics’,modern style plate tectonics occurred on its periphery in the form of accretionary *** detrital zircon and preserved geological record are compatible with an increase in the volume of continental crust during Columbia＇s lifespan; this is a consequence of the continuous accretionary processes along its *** quiescence in plate tectonic movements during Columbia＇s lifespan is correlative with a long period of stability in Earth＇s atmospheric and oceanic *** variability starting at 1.3 Ga in the environmental record coincides with the transformation of Columbia to Rodinia; thus,the link between plate tectonics and environmental change is strengthened with this interpretation of supercontinent history.

关键词： Rodinia Columbia Supercontinents Continental growth Lid tectonics Mesoproterozoic

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Deep seated magmas and their mantle roots:Introduction

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Geoscience Frontiers 2017年第4期8卷 617-619页

作者： Igor V.Ashchepkov Nick M.W.Roberts V.S.Sobolev Institute of Geology and Mineralogy SB RAS nerc Isotope Geosciences Laboratory British Geological Survey

In the last decade there has been a considerable effort to better understand the joint evolution of mafic and ultramafic magmatic systems and their deep mantle roots,through integrated petrological and thermo-barometric *** generation is regarded as the result of complex processes including melting,creation of channels for melt transfer,and interaction with the wall-rocks.

关键词： mantle magmatic creation branching melting garnet roots enriched geochemistry beneath

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The past 800 ka viewed through antarctic ice cores

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Episodes 2008年第2期31卷 219-221页

作者： Eric W Wolff british antarctic survey High Cross Madingley Road Cambridge CB3 0ET UK.

The later parts of the Quaternary are of particular importance for assessing our ability to understand the future operation of the Earth because the main boundary conditions are similar to those of today, and because we have a density of data that allows hypotheses to be tested rigorously. An important source of such data is antarctic ice cores, now extending back 800 ka, and containing signals both of climate, and of climate forcing factors. The antarctic ice core deuterium record, representing antarctic temperature, is one of the iconic Quaternary records.

关键词：第四纪地质时代南极冰川地球

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Paleobiological significance of the James Ross Basin

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Advances in Polar Science 2019年第3期30卷 186-198页

作者： J.Alistair CRAME british antarctic survey High CrossMadingley RoadCambridge CB3 0ETUK

The extensive Late Mesozoic–Early Cenozoic sedimentary succession exposed within the James Ross Basin,antarctica has huge potential to enhance paleobiological investigations into both the marine and terrestrial fossil *** excess of 7 km in total thickness and spanning the Early Cretaceous(Aptian)–Late Eocene in age,it represents an invaluable high-latitude(~65°S)site for comparison with lower latitude,tropical ones in an essentially greenhouse *** Early Cretaceous(Aptian–Albian)sequence is deep-water but there are indications of shallowing to inner shelf depths in both the Turonian and Coniacian *** first prolific shallow-water marine fauna occurs in the Santonian–Campanian Santa Marta Formation and this is followed by repeated occurrences through the later Campanian,Maastrichtian,Danian and Middle Eocene(Lutetian).In this study an attempt has been made to compare these antarctic faunas directly with the well-known ones of the same age from the US Gulf *** comparisons made for three time slices,Late Maastrichtian,Danian and Middle Eocene,indicate that the antarctic is characterised by both low taxonomic diversity and high levels of *** James Ross Basin is providing important evidence to indicate that the highest southern latitudes have always been characterised by a distinctive temperate biota,even on a pre-glacial *** roots of at least some elements of the modern Southern Ocean biota can be traced back to a Late Mesozoic–Early Cenozoic austral realm.

关键词： James Ross Basin biostratigraphy molluscan faunas US Gulf Coast biodiversity patterns evolutionof temperate biotas

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Generation and preservation of continental crust in the Grenville Orogeny

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Geoscience Frontiers 2015年第3期6卷 357-372页

作者： Christopher J.Spencer Peter A.Cawood Chris J.Hawkesworth Anthony R.Prave Nick M.W.Roberts Matthew S.A.Horstwood Martin J.Whitehouse EIMF Department of Earth and Environmental Sciences University of St Andrews nerc Isotope Geosciences Laboratory British Geological Survey Swedish Museum of Natural History and Nordic Center for Earth Evolution(NordCEE) Edinburgh Ion Microprobe Facility University of Edinburgh

Detrital zircons from modern sediments display an episodic temporal distribution of U-Pb crystallization ages forming a series of ＇peaks＇ and ＇troughs＇. The peaks are interpreted to represent either periods of enhanced generation of granitic magma perhaps associated with mantle overturn and superplume events, or preferential preservation of continental crust during global collisional orogenesis. The close association of those peaks with the assembly of supercontinents implies a causal relationship between collisional orogenesis and the presence of zircon age peaks. Here these two end-member models （episodic periodicity of increased magmatism versus selective preservation during collisional orogenesis） are assessed using U-Pb, Hf, and 0 analysis of detrital zircons from sedimentary successions deposited during the - 1.3-1.1 Ga accretionary, -1.1-0.9 Ga collisional, and 〈 0.9 Ga extensional collapse phases of the Grenville orogenic cycle in Labrador and Scotland. The pre-collisional, accretionary stage provides a baseline of continental crust present prior to orogenesis and is dominated by Archean and Paleoproterozoic age peaks associated with pre-1300 Ma Laurentian geology. Strata deposited during the Grenville Orogeny display similar Archean and Paleoproterozoic detrital populations along with a series of broad muted peaks from - 1500 to 1100 Ma. However, post-collisional sedimentary successions display a dominant age peak between 1085 and 985 Ma, similar to that observed in modern North American river sediments. Zircons within the post-orogenic sedimentary successions have progressively lower EHf and higher -lSO values from - 1800 to - 1200 Ma whereupon they have higher EHf and -3180 within the dominant 1085-985 Ma age peak. Furthermore, the Lu-Hf isotopic profile of the Grenville-related age peak is consistent with significant assimilation and contamination by older crustal material, The timing of this dominant age peak coincides with the peak of metamorphism and

关键词： Zircon Continental crust Grenville Orogeny Crustal preservation

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Belgica antarctica(Diptera: Chironomidae): A natural modelorganism for extreme environments

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Insect Science 2022年第1期29卷 2-20页

作者： Iryna Kozeretska Svitlana Serga Pavlo Kovalenko Volodymyr Gorobchyshynand Peter Convey National antarctic Scientific Center of Ukraine 01601Taras Shevchenko blv.16KyivUkraine Taras Shevchenko National Universityof Kyiv Department General and Medical Genetics01601Volodymyrska str.64/13KyivUkraine State Institution«Institute for Evolu-tionary Ecology of the National Academy of Sciences of Ukraine» Department of Population Dynamics03143Lebedeva str.37KyivUkraine and4British Antarctic SurveyNERCHigh CrossMadingley RoadCambridge CB30ETUnited Kingdom

Belgica antarctica(Diptera:Chironomidae),a brachypterous midge endemicto the maritime antarctic,was first described in *** more than a century of study,a vast amount of information has been compiled on the species(3750000 Google searchresults as of January 10,2021),encompassing its ecology and biology,life cycle and re-production,polytene chromosomes,physiology,biochemistry and,increasingly,***2014,***’s genome was sequenced,further boosting *** develop-mental stages can be cultured successfully in the *** together,this wealthof information allows the species to be viewed as a natural model organism for studies ofadaptation and function in extreme environments.

关键词： Belgica antarctica Chironomidae stress adaptation antarctica

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"Miles wide and miles deep"-Exploring the depth and breadth of geoscience during the first ten years of Geoscience Frontiers

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Geoscience Frontiers 2019年第3期10卷 1219-1221页

作者： Christopher J. Spencer Nick M.W.Roberts Damian Nance The Institute of Geoscience Research (TIGeR) School of Earth and Planetary Sciences Curtin University nerc Isotope Geosciences Laboratory British Geological Survey Department of Geological Sciences Ohio University Department of Geology and Geophysics Yale University

When early explorers first crossed the Platte River in what is now Nebraska (USA), it was said the river was “a mile wide and an inch deep”(Mokler, 1923;Smith, 1971). This phrase was used to describe not only the difficulty in crossing the river but also in navigating its length. The trouble with a river being too wide is the risk that it won’t provide the depth necessary to be useful. The same thing can be said of multidisciplinary scientific journals. While a journal can claim to be multidisciplinary, there is a risk of it being so broad that its articles can only engage the reader at a superficial level. Nothing could be further from the truth with Geoscience Frontiers. Over the past ten years, this journal has successfully navigated the wide breadth of geoscience while providing a level of depth and detail that rivals discipline-specific journals.

关键词： engage its was can past be is now

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Report on IAMAS Activity since 2015 and the IAPSO-IAMAS-IAGA Scientific Assembly--Good Hope for Earth Sciences

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Advances in Atmospheric Sciences 2018年第4期35卷 371-375页

作者： John TURNER Teruyuki NAKAJIMA british antarctic survey High Cross Madingley Road Cambridge CB3 0ET United Kingdom Japan Aerospace Exploration Agency 2-1-1 Sengen Tsukuba Ibaraki 305-8505 Japan

Three associations of the International Union of Geodesy and Geophysics （IUGG）--International Association for the Physical Sciences of the Oceans （IAPSO）, International Association of Meteorology and Atmospheric Sciences （IA- MAS） and International Association of Geomagnetism and Aeronomy （IAGA）--held their joint Scientific Assembly over 27 August-1 September in Cape Town, South Africa. This was the first full IAMAS assembly to be held in Africa （Figs. 1 ＆ 2）.

关键词： MAS Good Hope for Earth Sciences Report on IAMAS Activity since 2015 and the IAPSO-IAMAS-IAGA Scientific Assembly

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Lid tectonics-Preface

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Geoscience Frontiers 2018年第1期9卷 1-2页

作者： Craig O’Neill NickM.W.Roberts Macquarie Planetary Research Centre Department of Earth and Planetary ScienceMacquarie UniversitySydneyNSW 2019Australia nerc Isotope Geosciences Laboratory British Geological SurveyNottinghamNG12 5GGUK

The idea that plate tectonics may not have operated deep in Earth’s Precambrian past has a long legacy. What predated plate tectonics is unknown, and advances in data - from geochemical,geological and tectonic, to paleomagnetic, as well as modelling approaches,and planetary science, have the potential to contribute significantly to the debate. To contrast with the activity of plate tectonics,in this issue we use the term ‘lid tectonics’ to encapsulate a variety of envisaged regimes e from stagnant, sluggish, plutonicsquishy,or heat pipe - which are characterized by comparatively subdued tectonic *** special issue of Geoscience Frontiers aims to present a snapshot of current research in the field of lid-tectonics - from detailed field interpretations, to global conceptual models, data compilations,and insights from simulations, and provide unique insights into both the Precambrian Earth, and the dynamics of lid-tectonics.

关键词： plate tectonics Earth’s Precambrian

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