Abstract This study investigated a continuous sediment core, retrieved from the deepest part in Lake Hovsgol, northwestern Mongolia. Its surrounds are occupied by a continuous Siberian permafrost zone. Distinct geochemical and lithological features suggest that the watershed soil was moistened during the last deglaciation, associated with climate amelioration. Especially, the calcareous glacial clay layers (ca 13.7 and ca 11.0 cal. ka 34 BP), with high sulfur content peaks and positive shifts of δ S values, well correlate with the timing of meltwater pulses 1A and 1B, leading to rapid warming such as B?lling/Aller?d and Preboreal Holocene, respectively. This finding allows our interpretation for the calcareous glacial clay layers produced by landslide- induced debris flow, which resulted from intensive water discharge from rapid thawing of permafrost during the abrupt warming periods. Our correlation with Lake Baikal records suggests that these permafrost thawings have accelerated over the area of the Selenga drainage basin (continental interior Eurasia).

Kelso, J.E., Baker, M.A., 2020. Organic matter is a mixture of terrestrial, autochthonous, and wastewater effluent in an urban river. Frontiers in Environmental Science 7, 202. doi: 10.3389/fenvs.2019. 00202. https://www.frontiersin.org/article/10.3389/fenvs.2019. 00202

Terrestrially derived organic matter (OM) is known to dominate the OMpool in reference watersheds. Urban watersheds are known to receive large OMloads compared to reference watersheds, but the proportion of terrestrial, autochthonous, and anthropogenic (e.g., wastewater effluent) sources of OMin urban watersheds remains unknown. Organic matter was identified as a pollutant of concern in the Jordan River, an urban river in the Salt Lake Basin, U.S.A. Our objective was to identify autochthonous, terrestrial, and anthropogenic sources of three size-classes of OMto the Jordan River to inform OMreduction strategies within the watershed. Samples of coarse particulate OM(CPOM), fine particulate OM(FPOM), and dissolved OM(DOM) were analyzed for stable isotopes of carbon, nitrogen, and hydrogen. Stable isotope values of OMwere used for Bayesian and graphical gradient-based mixing models to identify autochthonous, terrestrial, and anthropogenic sources. Fluorescent properties of DOM were also used to characterize the sources and composition of DOM. CPOM was primarily terrestrially derived with increased autochthonous inputs from macrophytes in warm months. FPOM was a mixture of terrestrial, autochthonous, and wastewater effluent throughout the year. DOM was primarily from wastewater effluent as well as DOM with isotope signatures unique to DOM from Utah Lake. Characterization of OMin urban rivers will help inform conceptual models of OMdynamics and load management in urban ecosystems.

Khan, I., Zhong, N., Luo, Q., Ai, J., Yao, L., Luo, P., 2020. Maceral composition and origin of organic matter input in Neoproterozoic - Lower Cambrian organic-rich shales of Salt Range Formation, upper Indus Basin, Pakistan. International Journal of Coal Geology 217, 103319.

http://www.sciencedirect.com/science/article/pii/S0166516219304422 The appropriate thermal maturity (oil window or lower) of the Neoproterozoic rocks is a prerequisite for preserving robust and primary biological assemblages. The Neoproterozoic - Lower Cambrian organic-rich shales present in the upper part of Salt Range Formation, Pakistan, with abundant organic matter (OM) (total organic carbon (TOC) up to 46%) at relatively low thermal maturity (protobitumen reflectance, BR = 0.2- o 0.4%), represents by far the lowest-thermal maturity Neoproterozoic - Lower Cambrian rocks analyzed to date. The detailed petrographic description of Neoproterozoic - Lower Cambrian organic matter in the current study was lacking from previous source-rock studies of coeval strata from Oman, Eastern Siberia, Australia, and elsewhere. Eight organic-rich shales of the Salt Range Formation from three different outcrops have been analyzed for maceral composition and source rock characterization using organic petrography, scanning electron microscopy and standard source rock assessment techniques. The organic petrography reveals the organic-rich shales are predominantly composed of alginites (lamalginite and telalginite), bituminite, protobitumen, and mineral-bituminous groundmass. Overall, the maceral assemblages suggest the deposition of these shales took place under a salinity-stratified water-column in a shallow restricted basin, where both oxygenic and anoxygenic modes of primary production were operative. The top oxygenated part of the water- column was populated with the phototropic mat-forming cyanobacterium, whereas the lower, low-dissolved oxygen zone was dominated by algal mats and sulphate reduction bacteria. The rare and scattered thucholites present within the Salt Range Formation shales were derived from the radiation-induced polymerization of