Geoconservation and geodiversity for sustainable development in Madagascar

Madagascar is well known for its unique and rare natural beauty, and it is one of the biodiversity hotspots for conservation priorities. Many efforts have been made for the protection of biodiversity, yet initiatives towards the conservation of geodiversity are often neglected. eoconservation refers to the conservation of geological diversity or geodiversity, and it is often applied to a specific location, known as a geosite, where important earth features (geological, paleontological, geomorphological, hydrological and pedological) are protected, preserved and managed. Madagascar is very rich in natural resources and has many spectacular geological features, such as the beautiful gorges and canyons of Isalo, Tsingy de Bemaraha, Ankarana caves, hot springs and volcanic lakes of Itasy, all of which should be conserved and protected by local authorities, the private sector and local communities. Such initiatives can not only help to maintain and protect geological sites of particular importance, but also contribute to sustainable economic development. This essay aims to introduce geoconservation and sustainability in Madagascar, and to increase public knowledge and awareness of geodiversity and its conservation. The creation of geological tourism sites or geoparks is undoubtedly one of the most important steps to promote the conservation of geosites, and the promotion of earth science education should help expand and consolidate their protection

Zircon U–Pb geochronology and geochemistry of rhyolitic tuff, granite porphyry and syenogranite in the Lengshuikeng ore district, SE China: implications for a continental arc to intra-arc rift setting

SE China is well known for its Mesozoic large-scale granitoid plutons and associated ore deposits. Here, zircon U–Pb geochronological and geochemical data have been used to better constrain the petrogenesis of the igneous rocks associated with porphyry Ag–Pb–Zn deposits in the Lengshuikeng ore district, SE China. The Lengshuikeng rhyolitic tuff, granite porphyry and syenogranite yielded zircon U–Pb ages of 161, 155 and 138 Ma, respectively. The Lengshuikeng granite porphyries belong to calc-alkaline series and show fractionated I-type affinities. The rhyolitic tuffs show almost similar characteristics as the granite porphyries. The Lengshuikeng syenogranites are all alkali-rich and show A-type affinities. The syenogranites have high contents of high field strength elements such as Nb, Ta, Zr, Hf; with Zr + Nb + Ce + Y contents of >350 ppm. Chondrite-normalized REE patterns show relative enrichment of LREEs and strong negative Eu anomalies. The Lengshuikeng granite porphyries, syenogranites and tuffs were probably derived from partial melting of underlying Proterozoic metasedimentary rocks with minor addition of mantle-derived magmas, accompanied by fractional crystallization. Detailed petrologic and geochemical data for the Jurassic igneous rocks from the Lengshuikeng ore district imply that during the Late Jurassic, SE China on the southeast of the Shi-Hang zone was a continental arc associated with the subduction of the Palaeo-Pacific plate and that since the beginning of the Early Cretaceous an intra-arc rift has been formed along the Shi-Hang zone