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The evolutionary dynamics of El Nino Southern Oscillation (ENSO) over the last glacial period remains understudied, despite its potential in providing a cold case for climate sensitivity studies. Here, we investigate SE Asian-Pacific paleoclimate records to decipher the dominant underlying mechanism that governed tropical Asian-Pacific hydrology during MIS 3. Our results suggest that the glacial emergence of the Sunda Shelf likely altered the atmospheric circulation pattern in Southeast (SE) Asia and led to the realignment of rainfall patterns between Thailand and Indonesia during the last glacial period. We also propose that the long-term hydrological regime change in the tropical Asian-Pacific region during MIS 3 was mainly influenced by an El Nino-like mechanism. An intense El Nino-like condition led to strong aridity in SE Asia during mid MIS 3. By late MIS 3, an enhanced seasonality dampened the intensity of the El Nino-like conditions, thus, leading to muted aridity in SE Asia. The alternating warm and wet summer months and droughts during winter favoured the proliferation of C4 plant types in Northern Thailand from mid MIS 3 to late MIS 3.

XRF core scanning has evolved to become a standard analytical technique for the rapid assessment of elemental, density and textural variations in a wide range of sediments and other materials, with applications ranging from palaeoceanography, paleoclimatology, geology, and environmental forensics to environmental protection. In general, scanning provides rapid, non-destructive acquisition of elemental and textural variations at sub-millimetre resolution for a wide range of materials. Numerous procedural adaptations have been developed for the growing number of applications, such as analyses of unconsolidated, water-rich sediments, powdered soil samples, or resin bags. Here, practical expertise and guidance from the Itrax community, gained over 15 years, is presented that should provide insights for new and experienced users.

The dynamics of Northern Hemisphere ice sheets during Late Quaternary glacials have yet been dominantly examined from a Laurentide Ice Sheet perspective, which helped shaping the idea of moisture-starved glacials and small-scale ice volume variability. However, the waxing and waning of the European Ice Sheet (EIS) casts doubt on this perception. Understanding EIS dynamics under glacial boundary conditions is crucial because its meltwater pulses influence global climate by weakening deepwater formation in the North Atlantic Ocean. Here we show that the advection of subtropical water toward the continental margin of western Europe lead to enhanced moisture availability on the continent and fueled the growth of EIS lobes during glacials. This warm-water pooling was caused by monsoonally paced enhanced Mediterranean Outflow Water (MOW) entrainment that dragged subtropical surface waters toward the European margin. This mechanism presents a yet unrecognized marine-terrestrial pathway that allows low-latitude forcing to shape high-latitude glaciations. Plain Language Summary The build-up of glacial ice shields required large amounts of atmospheric precipitating as snow. However, under full glacial conditions, cold surface oceans reduce the amount of evaporation, which counteracts the growth of large continental ice shields. Our study aims to unravel the source and transport pathways of moisture that helped to rapidly form the European Ice Shield during the past two glacials. We propose the novel concept that the outflow of dense Mediterranean water into the North Atlantic played a decisive role as it helped to "drag" warm surface waters toward the European Margin by strengthening the Azores Current. This warm, subtropical water current supplied vast amounts of moisture, which then was transported northward into continental Europe and fueled ice sheet growth. The strength of Mediterranean Outflow Water discharge into the Atlantic strongly depends on monsoonal activity in i

Biological proxies from the Sokli Eemian (Marine Isotope Stage 5e) paleolake sequence from northeast Finland have previously shown that, unlike many postglacial records from boreal sites, the lake becomes increasingly eutrophic over time. Here, principal components (PC) were extracted from a high resolution multi-element XRF core scanning dataset to describe minerogenic input from the wider catchment (PC1), the input of S, Fe, Mn, and Ca-rich detrital material from the surrounding Sokli Carbonatite Massif (PC2), and chemical weathering (PC3). Minerogenic inputs to the lake were elevated early in the record and during two abrupt cooling events when soils and vegetation in the catchment were poor. Chemical weathering in the catchment generally increased over time, coinciding with higher air temperatures, catchment productivity, and the presence of acidic conifer species. Abiotic edaphic processes play a key role in lake ontogeny at this site stemming from the base cation- and nutrient-rich bedrock, which supports lake alkalinity and productivity. The climate history at this site, and its integrated effects on the lake system, appear to override development processes and alters its long-term trajectory.

The Southeast Asian mainland is located in the central path of the Asian summer monsoon, a region where paleoclimatic data are still sparse. Here we present a multi-proxy (TOC, C/N, delta C-13, biogenic silica, and XRF elemental data) study of a 1.5 m sediment/peat sequence from Lake Pa Kho, northeast Thailand, which is supported by 20 AMS C-14 ages. Hydroclimatic reconstructions for Pa Kho suggest a strengthened summer monsoon between BC 170-AD 370, AD 800-960, and after AD 1450; and a weakening of the summer monsoon between AD 370-800, and AD 1300-1450. Increased run-off and a higher nutrient supply after AD 1700 can be linked to agricultural intensification and land-use changes in the region. This study fills an important gap in data coverage with respect to summer monsoon variability over Southeast Asia during the past 2000 years and enables the mean position of the Intertropical Convergence Zone (ITCZ) to be inferred based on comparisons with other regional studies. Intervals of strengthened/weaker summer monsoon rainfall suggest that the mean position of the ITCZ was located as far north as 35 degrees N between BC 170-AD 370 and AD 800-960, whereas it likely did not reach above 17 degrees N during the drought intervals of AD 370-800 and AD 1300-1450. The spatial pattern of rainfall variation seems to have changed after AD 1450, when the inferred moisture history for Pa Kho indicates a more southerly location of the mean position of the summer ITCZ.