ALBERT

Description: The Lower Carboniferous Mobarak Formation in the Alborz Basin (northern Iran) was deposited along the northeastern margin of Gondwana in a carbonate ramp setting. This paper focuses on the Tournaisian stratigraphic interval of this formation that crops out at the Jaban section in the southwestern Central Alborz Basin. The following facies associations, representing different ramp palaeoenvironments, have been identified: (1) mudstone–wackestone outer-ramp facies; (2) crinoidal to skeletal grainstone–packstone mid-ramp facies; (3) peloidal to crinoidal grainstone–packstone inner-ramp facies; and (4) coastal facies, which include a variety of microbial laminated to oncoidal grainstones and mudstones with evaporitic pseudomorphs. This ramp profile was affected by frequent storms that were responsible for the formation of several skeletal to non-skeletal shoals in the distal mid-ramp to the most proximal inner-ramp areas. The development of the skeletal to non-skeletal shoals along the sea side of the ramp formed a semi-enclosed lagoon sensitive to the influence of both high tides and storm surges. The magnetic susceptibility ( in ) of all the samples was measured and compared with that of the facies from which the sample was taken. There is a clear link between in and the facies; the average in values were higher for the distal facies than for the proximal facies. The in profile of this Lower Carboniferous carbonate sequence reflects stratigraphic variations in response to relative changes in sea level and the input of detrital materials. In the context of the sequence stratigraphic framework, the average in values for lowstand and transgressive systems tract deposits are higher than for the highstand systems tract deposits. The clear link between in and facies indicates at least a partly preserved primary in signal related to the detrital inputs. However, to obtain a better understanding of the nature and origin of the minerals carrying the in , we performed hysteresis measurements on selected samples. It appears that the in signal is mainly carried by low-coercivity ferromagnetic minerals such as magnetite, with a mixture of relatively coarse grains (detrital fraction) and ultra-fine grains (probably formed during diagenesis).

Description: 〈span〉The importance of dust as a source of iron (Fe) for primary production in modern oceans is well studied but remains poorly explored for deep time. Vast dust deposits are well recognized from the late Paleozoic and provisionally implicated in primary production through Fe fertilization. Here, we document dust impacts on marine primary productivity in Moscovian (Pennsylvanian, ca. 307 Ma) and Asselian (Permian, ca. 295 Ma) carbonate strata from peri-Gondwanan terranes of Iran. Autotrophic contents of samples, detected by both point-count and lipid-biomarker analyses, track concentrations of highly reactive Fe, consistent with the hypothesis that dust stimulated primary productivity, also promoting carbonate precipitation. Additionally, highly reactive Fe tracks the fine-dust fraction. Dust-borne Fe fertilization increased organic and inorganic carbon cycling in low- and mid-latitude regions of Pangaea, maintaining low 〈span〉p〈/span〉CO〈sub〉2〈/sub〉.〈/span〉

Description: Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian – the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies – boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed “Deep Dust,” held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on clarifying the scientific drivers and key sites for coring continuous sections of Permian continental (loess, lacustrine, and associated) strata that preserve high-resolution records. Combined, the two workshops hosted a total of 91 participants representing 14 countries, with broad expertise. Discussions at Deep Dust 1.0 (USA) focused on the primary research questions of paleoclimate, paleoenvironments, and paleoecology of icehouse collapse and the run-up to the Great Dying and both the modern and Permian deep microbial biosphere. Auxiliary science topics included tectonics, induced seismicity, geothermal energy, and planetary science. Deep Dust 1.0 also addressed site selection as well as scientific approaches, logistical challenges, and broader impacts and included a mid-workshop field trip to view the Permian of Oklahoma. Deep Dust 2.0 focused specifically on honing the European target. The Anadarko Basin (Oklahoma) and Paris Basin (France) represent the most promising initial targets to capture complete or near-complete stratigraphic coverage through continental successions that serve as reference points for western and eastern equatorial Pangaea.