Mag.I.C. — Ágata Alveirinho Dias

Period 2014 – 2018

Funding FDCT 043/2014/A1

Host ISE / USJ, Macao

Principal Investigator Ágata Alveirinho Dias

About the project

MagIC aimed to develop a detailed digital cartographic map of the igneous rocks of Macao, useful for professionals from different areas and to understand the geological history of the territory. The main results included: (1) absolute age determination of Macao magmatic events; (2) mineralogical and geochemical constraints on magma evolution; and (3) a deeper understanding of the South China tectono-magmatic evolution.

Content updated March 2021 · originally hosted at ISE / USJ.

Abstract

Igneous rocks, in particular granitic ones, are of utmost importance to assess the tectonothermal evolution of continents and to decipher their geodynamic setting. During Mesozoic ages, the Southeastern China region (Cathaysia block), where Macao is localized, was affected by granitic plutonism generated during the Indosinian (Triassic) and Yanshanian orogenies (Jurassic–Cretaceous), overprinting all previous events in the South China Fold Belt (SCFB).

In Macao, the most complete document reporting the geology of the territory was published in 1992 under Luísa Ribeiro’s coordination (consultant of this project): the Macao Geological Map at 1:5000 scale and its memoir. Until this project, there was a significant gap in the knowledge of the geology and geodynamic evolution of Macao compared with surrounding areas such as Hong Kong and Guangdong, which had numerous SCI publications — whereas Macao had none.

MagIC developed a new trilingual digital geological map of Macao and determined the age and geodynamic evolution of Macao magmatic rocks. Macao granites were emplaced in two main periods ranging from 164.5 ± 0.6 Ma to 162.9 ± 0.7 Ma and 156.6 ± 0.2 Ma to 155.5 ± 0.8 Ma, separated by ca. 6 Ma. Inherited zircons point to a basement with ages up to Paleo-Proterozoic and late Archean. Younger dacitic rocks were dated at 150.6 ± 0.6 Ma and <120 Ma. The granitic suite was incrementally assembled over ca. 9 Ma; the transition to younger dacite dykes most likely marks a change in regional tectonic setting.

Isotope and geochemical compositions, model ages and mixing modelling strongly suggest that Macao granitic magmas were generated by partial melting of infracrustal medium-to-high K basaltic Paleo-Proterozoic to Mesoproterozoic protoliths heated by, and mixed to some degrees with, contemporaneous underplating and/or intrusion of hot, mantle-derived magmas. The Jurassic Macao granites are interpreted as produced in an intraplate extensional setting related to the foundering of a previously flat-slab (Paleo-Pacific plate) beneath SE China.

摘要

火成岩，尤其是花岗岩，对于揭开大陆的构造演化和动力学背景之谜至关重要。中生代时期，澳门所处的华东南板块（华夏古陆）受印支期（三叠纪）和燕山构造期所产生的花岗质岩浆影响，叠印了华南褶皱带以往所有的活动。澳门在地质和地理上归属于华夏陆块，从而为理解华南的地壳演化过程提供制约。

本项目编制了新的澳门三语数字地质图，并厘定了澳门岩浆岩年龄及其地球动力学演化：花岗岩侵入主要分为两期（164.5 ± 0.6 Ma–162.9 ± 0.7 Ma 与 156.6 ± 0.2 Ma–155.5 ± 0.8 Ma），继承锆石指示古元古代至晚太古代基底；英安质岩石年龄为 150.6 ± 0.6 Ma 和 <120 Ma。澳门侏罗纪花岗岩可解释为板内伸展环境中产生，与古太平洋板块由平板俯冲向板块拆沉的构造转变有关。

Geological map

Research team

Ágata Alveirinho Dias

PhD · Principal Investigator · ISE/USJ, Macao

João Mata

PhD · Team member · FCUL/IDL, Portugal

XinYu Gao

PhD · Team member · GIG/CAS, China

Luísa Ribeiro (Duarte)

PhD · Consultant · LNEG, Portugal

Varon Lou

MSc · Research Assistant · ISE/USJ, Macao

Pedro Quelhas

PhD Student · ISE/USJ, Macao · Dissertation defended 5 Dec 2019

Ricardo Borges

MSc · Research Assistant (GIS) · ISE/USJ, Macao

Collaborating institutions

IDL – Instituto Dom Luiz
LNEG – Laboratório Nacional de Energia e Geologia (Portugal)
JSGL – Jack Satterly Geochronology Laboratory (Canada)
GeoFCUL – Departamento de Geologia, Faculdade de Ciências da Universidade de Lisboa
HKU – University of Hong Kong

Companies and public institutions that contributed

Field visits and samples were supported by MPS (Macau Professional Services), LECM (Macau Laboratory of Civil Engineering), CGGC (China Gezhouba Group Corporation), Macau Golf and Country Club, SMG (Macao Meteorological and Geophysical Bureau), CEDD (Hong Kong Geological Survey), and other local partners.

Related overview: Geology of Macau.

Publications & communications

Peer-reviewed articles

Quelhas, P., Borges, R., Dias, Á. A., Ribeiro, L., Costa, P., Mata, J. (2021). Geological Map of the Macao Special Administrative Region (China). Journal of Maps, 17(2), 257–267. PDF · doi
Quelhas, P., Mata, J., Dias, Á. A. (2021). Magmatic evolution of garnet-bearing highly fractionated granitic rocks from Macao, Southeast China: Implications for granite-related mineralization processes. Journal of Earth Science. PDF · doi
Quelhas, P., Mata, J., Dias, Á. A. (2021). Evidences for mixed contribution of mantle, lower and upper crust to the genesis of Jurassic I-type granites from Macao, SE China. GSA Bulletin, 133(1–2), 37–56. PDF · doi
Quelhas, P., Dias, Á. A., Mata, J., Davis, D., Ribeiro, L. (2019). High-precision geochronology of Mesozoic magmatism in Macao, Southeast China: evidence for multistage granite emplacement. Geoscience Frontiers. PDF · doi

Conference abstracts & talks

Quelhas, P., Dias, Á. A., Mata, J., Wayne Davis, D. (2019). Goldschmidt Abstracts, Barcelona. Abstract
Quelhas, P., Mata, J., Lou, U. T., Ribeiro, M. L., Borges, R., Dias, Á. A. (2018). Source and evolution of Macao granitic magmas… XIV CGPLP / XIX SG, Trás-os-Montes e Alto Douro, Portugal. PDF
Quelhas, P. (2017). Mesozoic magmatism in Macao… Meeting on Mesozoic magmatism of Macao and Hong Kong, ISE, Macao (22–27 April 2017).
Quelhas, P., Mata, J., Lou, U. T., Ribeiro, M. L., Borges, R., Dias, Á. A. (2017). New Geochemical Constraints on I-Type Granites of Macao… 27th Goldschmidt Conference, Paris.
Quelhas, P. M., Mata, J., Lou, U. T., Ribeiro, M. R., Dias, Á. A. (2016). Mesozoic Granitic Magmatism in Macao, Southeast China. AGU Fall Meeting, San Francisco.
Dias, Á. A., Quelhas, P., Lou, U., Mata, J., Ribeiro, M. L. (2016). Petrology and Geochemistry of Granitic Rocks from Macao. 26th Goldschmidt Conference, Yokohama (poster).
Dias, Á. A. (2015). Presentation of the MagIC Project. First Meeting on the Geology of Macao, Macao.
Quelhas, P. (2016); Lou, V. (2015); Gao, X.-Y. (2015) — presentations at the First Meeting on the Geology of Macao.
Dias, Á. A. (2017). Opening talk about the geology of Macao, ISE meeting on Mesozoic magmatism of Macao and Hong Kong.

Other references (background literature)

Ribeiro, M. L. (2010). Macau, evolução do conhecimento geológico… Sociedade Geológica de Portugal. PDF
So, C. L. & Ribeiro, M. L. (1997). Portugal Macao Geology. Encyclopedia of World Regional Geology, pp. 620–621.
Ribeiro, M. L., Macedo, C. A. R., Ramos, J. M. F., Dias, R. P. (2000). K–Ar ages for the Macao granites… Congresso Internacional de Geologia, Rio de Janeiro.
Ribeiro, M. L., Ramos, J. M. F., Pereira, E., Dias, R. P. (1992). Carta Geológica de Macau na escala 1:5000 (inclui Notícia Explicativa). Serviços Geológicos de Portugal.
Marques, F. M. S. F. (1988). Contribuição para o conhecimento geológico e geotécnico do Território de Macau. MSc thesis, FCUL, 184 p.
Carrington da Costa, J. & Lemos, M. S. (1964). Fisiografia e Geologia da Província de Macau.
Lemos, M. S. (1963). Esboço Geológico da Província Ultramarina de Macau, 1:25 000.
Carrington da Costa, J. (1944). Geologia da Província de Macau. Bol. Soc. Geol. de Portugal, III, p. 47.