Professor Gastaldo’s research focuses on several key paleontological and sedimentological questions. These include: (1) the nature of the terrestrial fossil record over deep time; (2) the taphonomic processes (death, decay, disarticulation) involved in preserving the biosphere in the sedimentary record; (3) the nature of coal and coal-bearing systems; and (4) how fossil assemblages are used to understand ecosystem stability, perturbation (short- and long-term disturbance), turnover, extinction, and replacement.
Over the course of his career, he has undertaken both macrofossil and microfossil studies in, and published results with a wide variety of collaborators on:
- Modern (Holocene) coastal plain and deltaic, plant-and-peat accumulating regimes primarily in the: (1) Mobile-Tensaw River Delta, Alabama, USA; (2) Mahakam River Delta, Kalimantan, Indonesia; and (3) Rajang River Delta, Sarawak, East Malaysia.
Recently, Professor Gastaldo was featured in an article about NASA satellite imagery of the Rajang River Delta in their Earth Observatory Image of the Day : 5 March 2018
- The application of plant-fossil proxies to understanding and interpreting deep time climate states.
- Paleogene (66—23 mya) and Neogene (23—2.6 mya) coal-bearing intervals of central Europe, concentrating on Braunkohle (lignite-grade coal) and the landscapes in which they formed prior to, and including, the Miocene Thermal Optimum.
- Permian to Early Triassic (290—248 mya) rocks of the Karoo Basin, South Africa, testing the hypothesis of synchronous ecosystem collapse in response to the End Permian Mass Extinction (252.2 mya).
- Late Carboniferous (Pennsylvanian; 323 mya) to Early Permian (290 mya) ecosystems of the paleotropical equatorial belt in North America (Illinois, Black Warrior, Maritime basins), Europe, and China.
- Early Carboniferous (Mississippian; 330—323 mya) coal-bearing ecosystems in the Silesian Coal Basin of the Czech Republic and Poland.
- Early to Middle Devonian (408—388 mya) terrestrial and coastal ecosystems in Maine, New Brunswick, and the Canadian Maritimes.