We estimated the mineralogy of the effusive and explosive units at the Gardner shield volcano using Chandrayaan-1 Moon Mineralogy Mapper (M3) data and Lunar Reconnaissance Orbiter (LRO) Diviner data. We present a high-resolution 3D morphological map of the shield based on LRO Camera (LROC) Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) images and LOLA SLDEM data. The shield shows evidence of caldera subsidence with downsag and possible trapdoor style subsidence, including a central normal fault, partially developed fault-ring structure, resurgence, and subsidence blocks, two sinuous rilles, graben, lineaments, a parasitic cone SE of the central caldera. The shield comprises 5 prominent voluminous and 10 thinner effusive basaltic flow units, and one explosive unit displaying pyroclastic material at the center of the caldera. North of the caldera is Gardner crater, which is a simple bowl-shaped impact crater, formed after the shield, revealing fresh mineralogy from the shield and highlands, including high calcium pyroxene, olivine, and Fe-spinel. The crater has a dark debris flow on its eastern wall, landslides, a boulder cluster, boulder tracs, and lineaments. The shield presents a unique lava river channel originating from a secondary oblique fault ~ 5 km wide and spreading tens of kilometers at the northern part of Mare Tranquillitatis. Our volcano-tectonic study indicates that the Gardner shield is a science rich site with exploration potential to study basaltic caldera-forming volcanoes with in-situ pyroclastic resources as it comprises almost all the major compositional and structural aspects to understand lunar thermal, tectonic, and geological evolution.