Abstract

ABSTRACT A 1:12,000 geological map of the Macao Special Administrative Region has been produced through detailed field work supported by petrographic, mineralogical, geochronological and geochemical data obtained in previous studies. This map aims to represent a reliable tool to understand the geological evolution of the region and for management of the territory. The geology of Macao is dominated by two groups of Jurassic granitic rocks belonging to an intrusive suite located along the coast of Southeast China: Macao Group I (MGI: 164.5 ± 0.6 to 162.9 ± 0.7 Ma) and Macao Group II (MGII: 156.6 ± 0.2 to 155.5 ± 0.8 Ma), including the associated microgranite, aplite and pegmatite dikes and quartz veins. Remnants of the metasedimentary wall-rock are present as Devonian xenoliths enclosed within the granites. Younger Jurassic to Cretaceous andesite to dacite dikes (150.6 ± 0.6 to <120 Ma) intrude the granitic rocks. Additionally, Quaternary sedimentary deposits cover the older lithologies.

Highlights

  • Introduction and previous studiesGeological maps are fundamental to understand the geological evolution of a given area, being the primary source of information for land-use planning, assessment of geological hazards and identification of ground-water aquifers and potential ore bodies

  • Our main aim is to integrate the findings of the above-mentioned studies with more recent field, geochronological and geochemical data to provide the first comprehensive digital version of the geological map of the Macao, which will serve as an important basis for future geological studies

  • The digital topography obtained from the ASTER GDEM digital elevation model (DEM) Version 2 contained some anomalies that caused inaccuracies in several areas of the map, in highly-urbanized man-made landfill areas, which prompted the need to manually review all individual pixels of the satellite imagery pertaining to these areas and correct them

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Summary

Introduction and previous studies

Geological maps are fundamental to understand the geological evolution of a given area, being the primary source of information for land-use planning, assessment of geological hazards and identification of ground-water aquifers and potential ore bodies. For this reason, we surveyed the Macao Special Administrative Region (SAR) and, in the light of recent petrographic, mineralogical, geochronological and geochemical data (Quelhas et al, 2020, 2021a) and previous mapping (Ribeiro et al, 1992), produced a new geological map at 1:12,000 scale. Our main aim is to integrate the findings of the above-mentioned studies with more recent field, geochronological and geochemical data to provide the first comprehensive digital version of the geological map of the Macao (at 1:12,000 scale), which will serve as an important basis for future geological studies

Field work and sampling
Map construction
Geological background
Lithofacies
A brief note on the structural geology
Conclusions
Full Text
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