• Site Map

    All the web pages on the conference website







My Goldschmidt

Role functions

Abstract Details

(2020) Geochemical Constraints on Subduction Style in the Neoarchean: Magmatic Records from the Northern Yangtze Craton, China

Zhang S-B, Zheng Y-F, Wu P, He Q & Rong W


Sorry, the PDF cannot be displayed on your browser.

Download abstract

The author has not provided any additional details.

03e: Room 1, Thursday 25th June 06:51 - 06:54

Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.

Submitted by Aleksandra Redlinska-Marczynska on Thursday 25th June 05:18
Can you elaborate about why both type of magmatisms were contemporaneous in Neoarchean? Is it the matter of a heat ratio exclusively?
It is about the thermal state of the subduction zone in the Neoarchean. The Neoarchean subduction system has moderate thermal gradients of >20 OC /km. the modelling results of Bouihol et al. (2015) suggest that the mantle wedge can be hydrated and melted at depths of 55-72 km by the breakdown of amphibole and chlorite while subducted slab is also melted. Walowski et al. (2015) reported evidence from melt inclusions in Cascade arc basalts, which suggests that fluids interacted with the mantle wedge were derived from the mantle portion of the subducting slab. His modelling results imply that the fluids could induce the melting of the upper dehydrated portion of the subducting slab and the melts then migrate into the overlying mantle wedge to trigger further melting. This can be taken as a Phanerozoic analogue of the Neoarchean warm subduction. It is noted that the coeval development of TTG and calc-alkaline igneous rocks were not reported for the Eoarchean to Mesoarchean era. This means that either TTGs of early Archean were not produced by slab subduction or the subduction zones of early Archean were too hot to produce calc-alkaline magmas, or both. In other words, the contemporaneous development of both slab-derived and mantle wedge-derived magmatism in a warm subduction zone requires a goldilocks thermal structure. Too cold would result in normal arc magmatism like modern subduction zones whereas too hot would result in TTG magmas only. Our paper has been aacepted by Precambrian Research and will be online in a few days. You are welcome to download it and read the detailed discssion about this.

Sign in to ask a question.

Goldschmidt® is a registered trademark of the Geochemical Society and of the European Association of Geochemistry

Website managed and hosted by White Iron Conferences on behalf of the international geochemical community