@article{azmi_hyland_cotton_ghosh_raigemborn_tineo_hauswirth_insel_2025, title={Late Miocene expansion of grasslands in northwest Argentina linked to shifting hydroclimate: A complex interaction among tectonics, climate, and ecology}, volume={3}, ISSN={["1943-2674"]}, DOI={10.1130/B37868.1}, abstractNote={Factors driving the late Miocene expansion of C4 grasses remain widely debated. Here, we explored the role of climate and fire in controlling the abundance of C4 vegetation in the Angastaco Basin (Palo Pintado area) and La Viña Basin, NW Argentina, during the late Miocene (ca. 14−5.33 Ma). From paleosol horizons, we reconstructed paleoclimate and paleovegetation conditions using phytolith assemblages, geochemical and isotopic proxies, and polycyclic aromatic hydrocarbons (PAHs) to determine fire input. Our paleoclimate reconstructions suggest a stable mean annual temperature (MAT) of ∼10 °C and a gradual decline in mean annual precipitation (MAP) from 1100 mm yr−1 to 850 mm yr−1. Paleovegetation reconstructions from carbon isotopic composition and phytolith assemblages show a maximum of ∼15% C4 vegetation by 6 Ma. No significant increases in fire occurrence or establishment of fire feedbacks were identified from the PAH data. Though low in abundance (∼3% on average), our data identified the presence of C4 grass by the late Miocene. The lack of significant C4 expansion in this region was likely controlled by the changing hydroclimatic conditions associated with the Andes mountain range—increasing aridity and elevation constraints along with the lack of a fire feedback might have limited the distribution of C4 vegetation.}, journal={GEOLOGICAL SOCIETY OF AMERICA BULLETIN}, author={Azmi, Iffat and Hyland, Ethan and Cotton, Jennifer and Ghosh, Adit and Raigemborn, Maria Sol and Tineo, David and Hauswirth, Scott and Insel, Nadja}, year={2025}, month={Mar} }
 @article{azmi_goldberg_2024, title={Facies analysis and depositional model of the Midcontinent Rift System in Kansas, USA}, ISSN={["2055-4877"]}, DOI={10.1002/dep2.275}, abstractNote={Abstract The Midcontinent Rift System of North America is one of the oldest continental rifts but rifting ceased before continental breakup. The southern segment of the Midcontinent Rift System lies in Kansas, USA, where the stratigraphic succession and rift evolution are largely unknown. This study analysed the rift basin infill in this part of the Midcontinent Rift System to propose a depositional model. The Precambrian rift succession was described in discontinuous cores drilled in the Texaco Noel Poersch#1 well in Washington County. Sixteen lithofacies were identified and grouped into four different facies associations (fluvial, aeolian, lacustrine and alluvial fan). Overall, the studied succession comprises continental deposits accumulated dominantly in alluvial and aeolian settings, with the intermittent development of lacustrine systems. The proposed depositional models for the available core intervals indicate cyclic patterns of overfilled and underfilled phases within the rift basin. These changes in the accommodation‐to‐supply ratio were controlled by tectonism and probably modulated by climate during evolution in the syn‐rift phase. This study advances our understanding of variations across the Midcontinent Rift System.}, journal={DEPOSITIONAL RECORD}, author={Azmi, Iffat and Goldberg, Karin}, year={2024}, month={Feb} }