Sedimentology, Год журнала: 2024, Номер unknown

Опубликована: Дек. 27, 2024

ABSTRACT Emplacement of volcanics the Deccan Large Igneous Province in late‐Maastrichtian to early‐Danian has been linked global climatic perturbations and related biotic crisis. Sedimentary sequences associated with these lavas, known as infra‐trappean inter‐trappean successions, preserve records this induced changes. The Lameta Formation Jabalpur is type section for succession; it preserves a unique stack 13 calcrete profiles one calcic‐vertisol, which together constitute Mottled Nodular Beds. This stratigraphic unit evolved over significant time period, most likely few hundred thousand years Chron C29R, making suitable obtaining insights on terminal Cretaceous palaeoclimatic variability. Micromorphological, clay‐mineralogical, geochemical stable carbon‐isotopic (organic matter) data calcretes Beds have used understand their genesis obtain variability during formation. These calcretes/calcareous palaeosol are largely characterized by alpha‐fabric development some biogenic features indicating predominantly evaporation/evapotranspiration driven carbonate precipitation minor biochemically precipitation, respectively. Strontium isotopic compositions fraction indicate derivation calcium from Precambrian Mahakoshal Group marbles. On basis multiple datasets, interpreted be pedogenic having formed soil‐vadose zone following per descensum model. Based multiproxy approach that includes micromorphology, clay‐mineralogy, geochemistry (Mean Annual Precipitation salinization) carbon isotope ratio matter), conditions formation C29R varied mostly semi‐arid sub‐humid, two intervening shorter arid episodes middle upper parts succession. broadly aligns recently suggested changes eruptive dynamics neighbouring Malwa Plateau volcanic province.

Язык: Английский