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Origins of the supercontinent cycle

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Geoscience Frontiers 2013年第4期4卷 439-448页

作者： r.damian nance J.Brendan Murphy Department of Geological Sciences.316 Clippinger Laboratories.Ohio University.Athens.OH 45701.USA Department of Earth Sciences st.Francis Xavier UniversityAntigonishNova Scotia B2G 2W5.Canada

The supercontinent cycle, by which Earth history is seen as having been punctuated by the episodic assembly and breakup of supercontinents, has influenced the rock record more than any other geologic phenomena, and its recognition is arguably the most important advance in Earth Science since plate tectonics. It documents fundamental aspects of the planet＇s interior dynamics and has charted the course of Earth＇s tectonic, climatic and biogeochemical evolution for billions of years. But while the widespread realization of the importance of supercontinents in Earth history is a relatively recent development, the supercontinent cycle was first proposed thirty years ago and episodicity in tectonic processes was recognized long before plate tectonics provided a potential explanation for its occurrence. With interest in the supercontinent cycle gaining momentum and the literature expanding rapidly, it is instructive to recall the historical context from which the concept developed. Here we examine the supercontinent cycle from this perspective by tracing its development from the early recognition of long-term epi- sodicity in tectonic processes, through the identification of tectonic cycles following the advent of plate tectonics, to the first realization that these phenomena were the manifestation of episodic superconti- nent assembly and breakup.

关键词： Supercontinent cyclePlate tectonicsTectonic episodicitySecular trends

Switching from advancing to retreating subduction in the Neoproterozoic Tarim Craton, NW China: Implications for rodinia breakup

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Geoscience Frontiers 2021年第1期12卷 161-171页

作者： Guanghui Wu Shuai Yang Wei Liu r.damian nance Xin Chen Zecheng Wang Yang Xiao School of Geoscience and Technology Southwest Petroleum UniversityChengdu 610500China Southwest Petroleum University Division of Key Laboratory of Carbonate ReservoirsCNPCChengdu 610500China PetroChina research Institute of Petroleum Exploration&Development Beijing 100083China Department of Geological Sciences 316 Clippinger LaboratoriesOhio UniversityAthensOH 45701USA

Geodynamic drivers for the supercontinent cycle are generally attributed to either top-down(subduction-related)or bottom-up(mantle-related)*** geochemical data and U-Pb ages and Hf isotopic signatures for magmatic and detrital zircons from the Tarim Craton reveal a distinct change in subduction style during the *** subduction cycle is recorded in increasing and decreasing intensity of subduction-related magmatic rocks and time-equivalent sedimentary successions,and converse trends ofεHf(t)values and corresponding changes in crustal incubation *** trends are consistent with a switch from advancing to retreating *** switch likely occurred at ca.760 Ma when zirconεHf(t)values increase and crustal incubation times decrease following a transitional shift between 800 Ma and 760 Ma.A switch at this time is consistent with rodinia breakup and may have resulted in the late Neoproterozoic Tarim rift *** long-lived(ca.500 Ma)subduction recorded in the Tarim Craton suggests the predominance of a top-down process for rodinia breakup on this part of its margin.

关键词： Supercontinent breakup Top-down tectonics rodinia Subduction U-Pb-Hf isotopes

A brief history of the rheic Ocean

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Geoscience Frontiers 2012年第2期3卷 125-135页

作者： r.damian nance Gabriel Gutirrez-Alonso J.Duncan Keppie Ulf Linnemann J.Brendan Murphy Cecilio Quesada rob A.Strachan Nigel H.Woodcock Department of Geological Sciences 316 Clippinger Laboratories Ohio University Departamento de Geología Universidad de Salamanca 33708 Salamanca Departamento de Geología regional Instituto de Geología Universidad Nacional Autónoma de Mxico Senckenberg Naturhistorische Sammlungen Dresden Museum fur Mineralogie und Geologie Konigsbrucker Landstra βe 159D-01109 DresdenGermany Department of Earth Sciences St.Francis Xavier University Instituto Geolóogico y Minero de Espaa Ríos Rosas 2328003 MadridSpain School of Earth & Environmental Sciences University of Portsmouth Department of Earth Sciences University of Cambridge Downing StreetCambridge CB2 3EQUK

The rheic Ocean was one of the most important oceans of the Paleozoic Era. It lay between Laurentia and Gondwana from the Early Ordovician and closed to produce the vast Ouachita- Alleghanian-Variscan orogen during the assembly of Pangea. rifting began in the Cambrian as a continua- tion of Neoproterozoic orogenic activity and the ocean opened in the Early Ordovician with the separation of several Neoproterozoic arc terranes from the continental margin of northern Gondwana along the line of a former suture. The rapid rate of ocean opening suggests it was driven by slab pull in the outboard Iapetus Ocean. The ocean reached its greatest width with the closure of Iapetus and the accretion of the peri- Gondwanan arc terranes to Laurentia in the Silurian. Ocean closure began in the Devonian and continued through the Mississippian as Gondwana sutured to Laurussia to form Pangea. The ocean consequently plays a dominant role in the Appalachian-Ouachita orogeny of North America, in the basement geology of southern Europe, and in the Paleozoic sedimentary, structural and tectonothermal record from Middle America to the Middle East. Its closure brought the Paleozoic Era to an end.

关键词： rheic Ocean Variscan-Alleghanian-Ouachita orogen Pangea North America Europe

"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

Estrogen,male dominance and esophageal adenocarcinoma:Is there a link?

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World Journal of Gastroenterology 2012年第5期18卷 393-400页

作者： Huiqi Yang Olga A Sukocheva damian J Hussey David I Watson Huiqi Yang Olga A Sukocheva Damian Hussey DavidI Watson Department of Surgery Flinders Medical CentreFlinders University Bedford Park South Australia 5042 Australia Flinders Centre for Cancer Prevention and Control FlindersMedical Centre Bedford Park South Australia 5042

Esophageal adenocarcinoma is a cancer with poor prognosis, and its incidence has risen sharply over recent decades. Obesity is a major risk factor for developing this cancer and there is a clear male gender bias in the incidence that cannot be fully explained by known risk factors. It is possible that a difference in the expression of estrogen, or its signaling axes, may contribute to this gender bias. We undertook a com- prehensive literature search and analyzed the available data regarding estrogen and estrogen receptor expres- sion, and the possible sex-specific links with esopha- geal adenocarcinoma development. Potentially relevant associations between visceral vs subcutaneous fat deposition and estrogen expression, and the effect of crosstalk between estrogen and leptin signaling were identified. We also found limited studies suggesting a role for estrogen receptor 13 expression in esophageal adenocarcinoma development. The current literature supports speculation on an etiological role for estrogen in the male gender bias in esophageal adenocarcino- ma, but further studies are required.

关键词： Estrogen Estrogen receptors Male domi-nance Esophageal adenocarcinoma