I can tell you that the symbol is a representation of a bronze tripod, commonly used in Greek religious practices. I don't know what the significance of it being depicted on a shield is, but hopefully someone else will have some ideas.

Black figure could mean a little older, that is before the 5th BCE, but not necessarily. The style does look a little archaic. It's hard to tell from how the picture is cropped, it's maybe a hydria or a krater? The scene itself is probably significant although I'm not sure what it is - for some reason I'm thinking Troilus vs. Achilles. It could also be a scene from one of the Sacred Wars of the Amphictyonic League? Honestly I shouldn't be guessing like this - we'd need more information about the piece's provenance before discussion the possible meanings of the symbols.

Anyway, the tripod is itself a significant artifact and symbol. Two good books on that angle of it are 'Structure and History in Greek Mythology and Ritual', and 'Homo Necans, the Anthropology of Ancient Greek Sacrificial Ritual and Myth', both by Walter Burket.