Compositional variability of regoliths on equatorial highlands (East Timor). Source-rock control and competing effects of weathering and denudation

•Non-mobile elements discriminate Si-rich and Si-poor regoliths formed on distinct rock units.•Si-poor suites tend to be more affected by weathering than Si-rich suites.•Weathering extent better assessed by MIA and αAlMg in Si-poor regoliths.•Minor alteration and source rock variability compromise weathering assessments in Si-rich suites.•Chemical weathering is strongly limited by high denudation rates.