Astronomical insolation forcing is now well-established as the underlying metronome of Quaternary ice ages and Cenozoic climate carbon-cycle feedback mechanisms. However, its effects on earlier Eras (Mesozoic, Paleozoic, and pre-Cambrian) are less understood. In this presentation, I will evaluate various pre-Cenozoic modes of response to astronomical forcing, and provide an overview of the Earth System components that were particularly sensitive to astronomical forcing under evolving boundary conditions. Subsequently, the role of astronomical forcing in pacing the global carbon cycle in the Devonian warmhouse and Cretaceous hothouse worlds is discussed. Both periods are characterized by recurrent ocean anoxia and remarkably similar hypotheses exist regarding how astronomical forcing could have amplified a nutrient surplus (from chemical weathering and volcanism, respectively) to tip the ocean system into anoxia. The Triassic-Jurassic boundary cyclostratigraphy illustrates the importance of precession-scale time-control to understand feedback mechanisms and cause-and-effect chains at a resolution that is relevant for making analogies with the present-day. Finally, this presentation provides an outlook on the need for a coordinated approach, using so-called astrochronozones, to establish a fully astronomically-calibrated timescale for the Phanerozoic. Overall, I will highlight the need for a more comprehensive understanding of the role of astronomical insolation forcing in shaping Earth's climate over geologic time.

Sandy alluvial-, deltaic-, and tidal-facies sediments of the Paleoarchean Moodies Group (ca. 3,220 Ma) are preserved several km thick in the central Barberton Greenstone Belt, interspersed with diverse units representing substantial mafic to intermediate (sub-)volcanism. Densely biolaminated sandstones feature common, up to 6 m high fluid-escape structures which fed small sand volcanoes during prolonged and/or recurring discharge of gases, liquids, and solids. The to-date highest documented concentration of fluid-escape structures occurs in a single, largely silicified unit of tidal-facies sandstones ca. 150 m thick, traceable along strike for ca. 14 km and located stratigraphically ca. 1 km above the Lomati River Sill, a 15 km long mafic sill of Moodies intrusive age. Fluid-escape conduits are filled by sand, sericitic clay and fine-grained organic matter. Semiquantitative XRF scanning of several slabbed fluid-escape structures indicates that conduits are enriched in Fe, Cr, Ti, and Mg in comparison to the mean composition of adjacent beds, suggesting that fluid-escape structures may not only have formed due to overpressure build-up from decaying microbial mats in the shallow subsurface but also resulting from release of hydrothermal fluids generated in a thermal aureole above the cooling sill. This inference is also supported by sediment textures characteristic of argillaceous and sericitic alteration, Raman temperatures ca. 50 - 100°C above the regional maximum metamorphic temperature of 320 - 370°C, and associated peperites nearby. Surficial hydrothermal activity in the tidal zone would have likely boosted microbial growth. Surficial pre-compaction carbonation and silicification greatly facilitated the preservation of delicate microbial mats.

The Silurian record in the Siljan crater, Europe’s largest impact structure, in the succession at Baizitian (Sichuan Province) in South China, in other Swedish and Estonian sections, together with records from Laurentia and high latitude peri-Gondwana imply a series of glacial events during the Early Silurian. The associated climate shifts are expressed in stratigraphic sections as δ¹⁸O_apatite anomalies and subaerially exposed sequence boundaries with associated palaeokarst in the tropics and subtropics. During the continuing icehouse after the Hirnantian glacial maximum several stratigraphic gaps developed in the basal Silurian in many parts of the world due to extremely low sea levels, erosion, and first onlaps during deglaciations much later in Silurian times.

Our Telychian to Sheinwoodian chemostratigraphic data include several prominent excursions, such as the pronounced Manitowoc Carbon Isotope Excursion (Manitowoc CIE, ‘Manitowoc Excursion’), spanning the upper Pterospathodus eopennatus Zone and the lower Pterospathodus amorphognathoides amorphognathoides Superzone. Well-bracketed by conodont biostratigraphy, the Manitowoc CIE is an essential tie-point for a detailed correlation between the Baizitian succession in South China and the Telychian strata of Baltica and Laurentia.

Here we focus on the Early Silurian climate development spanning the Telychian Valgu glaciation (more widely recognized than older glacials during the Aeronian), the Manitowoc Icehouse including two short-term glacial events and the late Telychian Glaciation (LTG), , and the Sheinwoodian glaciation reflected by the Sheinwoodian Oxygen Isotope Excursion (SOIE) following directly after the maximum δ¹³C values of the widely known Early Sheinwoodian Carbon Isotope Excursion (ESCIE).

Modern-style plate tectonics is characterized by the global operation of deep and cold subduction involving ultrahigh-pressure and blueschist-facies metamorphism. This is a common process since the Neoproterozoic, but a couple of studies indicate similar processes have been active in the Paleoproterozoic, at least on the local scale. Particularly conspicuous are extreme ultrahigh-pressure conditions of ~7 GPa at thermal gradients <150°C/GPa proposed for metamorphic rocks of the Nordre Strømfjord shear zone in the western part of the Paleoproterozoic Nagssugtoqidian Orogen of Greenland (Glassley et al., 2014). By acquiring a large dataset of heavy minerals (n = 52,130) and garnet major-element composition integrated with mineral inclusion analysis (n = 2,669) from modern sands representing fresh and naturally mixed erosional material from the metamorphic rocks, we here intensely screened the area for potential occurrences of ultrahigh-pressure rocks and put constraints on the metamorphic evolution. Apart from the absence of any indications pointing to ultrahigh-pressure and low-temperature/high-pressure metamorphism, the results are well in accordance with a common Paleoproterozoic subduction−collision metamorphic evolution along a Barrovian-type intermediate temperature/pressure gradient with a pressure peak at the amphibolite−granulite−eclogite-facies transition and a temperature peak at medium- to high-pressure granulite-facies conditions. This is in strong contrast to the proposed ultrahigh-pressure conditions and low geothermal gradients, and challenges the existence of a Paleoproterozoic modern-style plate-tectonic regime in western Greenland.

For a robust interpretation in sedimentary provenance analysis studies (SPA) a combination of multiple methods is usually applied to a selected number of samples. To circumvent effects that perturb the provenance signal (e.g. hydraulic sorting) information on radiometric age, chemical composition and mineralogy is collected for mineral varieties usually by means of laser ablation inductively coupled mass spectrometry (LA-ICPMS), electron probe microanalyzer (EPMA), Raman micro-spectroscopy and polarized optical microscopy.

These methods have become increasingly efficient and allow for rapid analysis of statistically relevant numbers of samples which is fundamental to SPA. However, routine combination of these methods on the same grains is rarely realized and sample preparation quickly becomes a bottleneck when sample numbers are significantly increased. The latter is especially important to detect subtle variations in deposits due to processes operating on centennial to millennial time scales such as rapid climatic variability.

Here we present a workflow that is optimized for high throughput of silt to sand-sized sedimentary samples, which allows routine combination of optical microscopy, Raman micro-spectroscopy, EPMA and LA-ICPMS by means of machine learning methods. Due to the high degree of automatization our workflow enables to access sedimentary archives at high spatial and/or temporal resolution and will provide, depending on combined methods, single-grain datasets that contain information on grain-size, shape, roundness, color, mineralogy, degree of metamictization, chemical composition, trace element composition and radiometric age. We demonstrate innovative approaches in the relevant sample preparation steps and showcase data of several loess profiles highlighting the feasibility of our workflow.