Complex sentence: Additionally, the source for tested rock samples came from a mantle depleted in titanium and niobium and enriched in lead, strontium, barium, rubidium, and light rare earth elements, which, taken together, are indicative of arc-related basalts.
Split into simpler sentences: Additionally, the source for tested rock samples came from a depleted mantle. The presence of a depletion in titanium and niobium, as well as an enrichment in lead, strontium, barium, rubidium, and light rare earth elements, indicates arc-related basalts.