Supplemental Material: The newly discovered ca. 1.35 Ga metamafic rocks in the Oulongbuluke Block, NW China, and its record for transition from the Columbia to Rodinia supercontinent

Table S1: U-Th-Pb LA-ICP-MS data of zircons from metamafic rocks in the Oulongbuluke Block. Table S2: LA-MC-ICP-MS Lu-Hf isotope data of zircons from metamafic rocks in the Oulongbuluke Block. Table S3: Major and trace element compositions of metamafic rocks in the Oulongbuluke Block.

Supplemental Material: The newly discovered ca. 1.35 Ga metamafic rocks in the Oulongbuluke Block, NW China, and its record for transition from the Columbia to Rodinia supercontinent

Table S1: U-Th-Pb LA-ICP-MS data of zircons from metamafic rocks in the Oulongbuluke Block. Table S2: LA-MC-ICP-MS Lu-Hf isotope data of zircons from metamafic rocks in the Oulongbuluke Block. Table S3: Major and trace element compositions of metamafic rocks in the Oulongbuluke Block.

Geochemical indications for the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals in terrestrial sediments of the Canadian Arctic

During the late Paleocene to early Eocene, clastic fluvial sediments and coals were deposited in northern high latitudes as part of the Marga­ret Formation at Stenkul Fiord (Ellesmere Island, Nunavut, Canada). Syn-sedimentary tectonic movements of the Eurekan deformation continu­ously affected these terrestrial sediments. Different volcanic ash layers occur, and unconformities subdivide the deposits into four sedimentary units. Rare vertebrate fossils indicate an early Eocene (Graybullian) age for the upper part of the Stenkul Fiord outcrop. Here, we present carbon isotope data of bulk coal, related organic-rich mud and siltstones, a plant leaf wax-derived alkane, and additional plant remains. These data provide a complete carbon isotope record of one stratigraphic section with defined unconformity positions and in relation to other Eurekan deformation features. A previously dated ash layer MA-1 provided a U-Pb zircon age of 53.7 Ma and is used as a stratigraphic tie point, together with a discrete negative carbon isotope excursion found above MA-1 in a closely sampled coal seam. The excursion is identified as the likely expression of the I-1 hyperthermal event. Based on our isotope data that reflect the early Eocene dynamics of the carbon cycle, this tie point, and previous paleontological constraints from vertebrate fossils, the locations of the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals and their extent along the complete section are herein identified. Within the intervals of the PETM and ETM-2 hyperthermal events, increasing amounts of clastic sediments reached the site toward the respective end of the event. This is interpreted as a response of the fluvial depositional system to an intensified hydrological system during the hyperthermal events. Our study establishes an enhanced stratigraphic framework allowing for the calcula­tion of average sedimentation rates of different intervals and considerations on the completeness of the stratigraphic record. As one of the few high-latitude outcrops of early Eocene terrestrial sediments, the Stenkul Fiord location offers further possibilities to study the effects of extreme warming events in the Paleogene.

Supplemental Material: Geology of Chief Joseph Pass, Wyoming: Crest of Rattlesnake Mountain anticline and escape path of the Eocene Heart Mountain slide

File S1: AMS data. File S2: Dike paleopole data. File S3: O and C isotope data. File S4: Fluid-inclusion data. File S5: U-Pb ages

Supplemental Material: Geology of Chief Joseph Pass, Wyoming: Crest of Rattlesnake Mountain anticline and escape path of the Eocene Heart Mountain slide

File S1: AMS data. File S2: Dike paleopole data. File S3: O and C isotope data. File S4: Fluid-inclusion data. File S5: U-Pb ages

Presolar Grains

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. Presolar grains are dust produced by stars that died before the formation of the Earth’s solar system. Stardust grains condense out of cooling gas lost via stellar winds from the surface of low-mass stars and stellar explosions and become a constituent of interstellar medium (ISM). About 4.6 Ga, a molecular cloud in the ISM collapsed to form the solar system, during which some primordial stardust grains from the ISM survived and were incorporated into small bodies formed in the early solar system. Some of these small solar system bodies, including asteroids and comets, escaped planet formation and have remained minimally altered, thus preserving their initially incorporated presolar grains. Fragments of asteroids and comets are collected on Earth as interplanetary dust particles (IDPs) and meteorites. Presolar grains have been found in primitive IDPs and chondrites—stony meteorites that have not been modified by either melting or differentiation of their parent bodies. Presolar grains, typically less than a few μm, are identified in primitive extraterrestrial materials by their unique isotopic signatures, revealing the effects of galactic chemical evolution (GCE), stellar nucleosynthesis, and cosmic ray exposure. Comparisons of presolar grain isotope data with stellar observations and nucleosynthesis model calculations suggest that presolar grains were dominantly sourced from asymptotic giant branch stars and core-collapse supernovae, although there are still ambiguities in assigning the type of star to some groups of grains. So far, various presolar phases have been identified such as corundum, olivine, and silicon carbide, reflecting diverse condensation environments in different types of stars. The abundances of different presolar phases in primitive extraterrestrial materials vary widely, ranging from a few percent for presolar silicates to a few parts per million for presolar oxides. Presolar grain studies rely on the synergy between astronomy, astrophysics, nuclear physics, and cosmochemistry. To understand the stellar sources of presolar grains, it is important to compare isotope data of presolar grains to astronomical observations for different types of stellar objects. When such astronomical observations are unavailable, stellar nucleosynthesis models must be relied upon, which require inputs of (a) initial stellar composition estimated based on solar system nuclide abundances, (b) stellar evolution models, and (c) nuclear reaction rates determined by theories and laboratory experiments. Once the stellar source of a group of presolar grains is ascertained, isotope information extracted from the grains can then be used to constrain stellar mixing processes, nuclear reaction rates, GCE, and the ISM residence times of the grains. In addition, crystal structures and chemical compositions of presolar grains can provide information to infer dust condensation conditions in their parent stars, while abundances of presolar grains in primitive chondrites can help constrain secondary processing experienced by the parent asteroids of their host chondrites. Since the discovery of presolar grains in meteorites in 1980s, a diverse array of information about stars and GCE has been gleaned by studying them. Technological advances will likely allow for the discovery of additional types of presolar grains and analysis of smaller, more typical presolar grains in the future.

Potential influence of a planned landfill on a high karst plateau in Southwestern Montenegro to nearby karstic springs

The potential threat of a landfill projected on a high karst plateau in southwest Montenegro is investigated with respect to the subjacent nearby springs. The locality is called Duboki do. As the springs are used for drinking water supply this investigation is urgently needed. For the springs exist two hypotheses concerning their catchment area: I) from the high karst plateau, or II) from a topographically lower area. The stable H- and O-isotope ratios of water samples from the springs are compared with precipitation isotope data, to reveal the catchment area of the springs. The isotope results indicate that the catchment area of the springs is at higher altitude fitting to, and in good agreement with, winter precipitation from the high karst plateau of the planned land-fill locality.

Can we use precipitation isotope outputs of isotopic general circulation models to improve hydrological modeling in large mountainous catchments on the Tibetan Plateau?

Issues related to large uncertainty and parameter equifinality have posed big challenges for hydrological modeling in cold regions where runoff generation processes are particularly complicated. Tracer-aided hydrological models that integrate the transportation and fractionation processes of water stable isotope are increasingly used to constrain parameter uncertainty and refine the parameterizations of specific hydrological processes in cold regions. However, the common unavailability of site sampling of spatially distributed precipitation isotopes hampers the practical applications of tracer-aided models in large-scale catchments. This study, taking the precipitation isotope data (isotopes-incorporated global spectral model – isoGSM) derived from the isotopic general circulation models (iGCMs) as an example, explored its utility in driving a tracer-aided hydrological model in the Yarlung Tsangpo River basin (YTR; around 2×105 km2, with a mean elevation of 4875 m) on the Tibetan Plateau (TP). The isoGSM product was firstly corrected based on the biases between gridded precipitation isotope estimates and the limited site sampling measurements. Model simulations driven by the corrected isoGSM data were then compared with those forced by spatially interpolated precipitation isotopes from site sampling measurements. Our results indicated that (1) spatial precipitation isotopes derived from the isoGSM data helped to reduce modeling uncertainty and improve parameter identifiability in a large mountainous catchment on the TP, compared to a calibration method using discharge and snow cover area fraction without any information on water isotopes; (2) model parameters estimated by the corrected isoGSM data presented higher transferability to nested subbasins and produced higher model performance in the validation period than that estimated by the interpolated precipitation isotope data from site sampling measurements; (3) model calibration forced by the corrected isoGSM data successfully rejected parameter sets that overestimated glacier melt contribution and gave more reliable contributions of runoff components, indicating the corrected isoGSM data served as a better choice to provide informative spatial precipitation isotope than the interpolated data from site sampling measurements at the macro scale. This work suggested plausible utility of combining isoGSM data with measurements, even from a sparse sampling network, in improving hydrological modeling in large high mountain basins.