The major- and trace-element chemistry of pyrite and arsenopyrite from the mesothermal Roudný gold deposits was studied by electron microprobe and laser ablation ICP-MS techniques. In total, four generations of pyrite and two of arsenopyrite were distinguished. The pyrite is enriched in As through an Fe (As_xS_1–x)₂substitution mechanism. The As-rich zones of pyrite-2 (up to 4.5 wt.% As) are also enriched in gold (up to 20 ppm), lead (commonly up to 220 ppm, exceptionally up to 1500 ppm) and antimony (commonly <600 ppm, rarely up to 1350 ppm). Positive correlation of As and Au in the studied pyrites is not coupled with an Fe deficiency, in contrast to Au-rich As-bearing pyrites in Carlintype gold deposits. The As-rich pyrite-2 coprecipitated with the Sb-rich (1 –4.2 wt.%) and Au-rich (40 –150 ppm) arsenopyrite-1. The younger arsenopyrite-2 is significantly less enriched in these elements (0 –70 ppm of Au).The chemical zonality of pyrites in the Roudný gold deposits reflects the chemical evolution of orebearing fluids that are not observed in any other mineral phases. The data available suggest relatively high activity of sulphur and low activities of arsenic and gold during crystallization of the older pyrite generation (pyrite-1). Later, after particular dissolution of pyrite-1, Au-rich As-bearing pyrite-2 and arsenopyrite precipitated. These facts suggest a marked increase in the arsenic and gold activities in ore-bearing fluids. The As-content of pyrite-2 decreases in an oscillatory manner from the core to the rim, reflecting changes in the As activity or/and in theP-Tconditions. The As-bearing pyrites were formed at temperatures of at least 320–330°C, based on arsenopyrite thermometers and fluid inclusion data.

The Early Turonian interval represents a unique confluence of climatic and oceanographic conditions including peak surface temperatures, high greenhouse‐gas concentrations, and maximum Phanerozoic sea level. The susceptibility of this climate mode to astronomical insolation forcing remains poorly understood partly due to a limited time control and unknown phasing of astronomical cycles in this interval. Here, we offer a refined astrochronology of the Early Turonian based on laterally consistent precession signals preserved in offshore strata of the Bohemian Cretaceous Basin (central Europe). Pristine amplitude modulation verified through interference patterns in depth‐frequency plots provides a robust indication of ∼100 and 405‐kyr eccentricity phases (maxima and minima) that are pinned to ammonite biozones and new carbon‐isotope data from two cores. The Early Turonian is estimated as 885 ± 41 (2σ) thousand years (kyr) in duration, with the Cenomanian/Turonian boundary predating the first Turonian 405‐kyr maximum (no. 232 in the Geological Time Scale 2020) by 82 ± 70 (2σ) kyr. The results support a possible link of the recovery from Oceanic Anoxic Event II to increasing magnitude of seasonal insolation extremes due to rising eccentricity on 405‐kyr and million‐year (Myr) time scales. Superimposed upon this trend are small‐scale carbon‐isotope anomalies the pacing of which passes from ∼110 kyr, resembling short eccentricity, to ∼170 kyr, possibly related to obliquity modulation. This eccentricity‐to‐obliquity transition, paralleling the rising phase of Myr‐scale eccentricity, suggests decoupling of the carbon‐cycle perturbations from low‐latitude seasonal insolation. Mid‐latitude to high‐latitude carbon reservoirs became involved toward the Middle Turonian.