ALBERT

Description: Crop adaptation to climate change requires accelerated crop variety introduction accompanied by recommendations to help farmers match the best variety with their field contexts. Existing approaches to generate these recommendations lack scalability and predictivity in marginal production environments. We tested if crowdsourced citizen science can address this challenge, producing empirical data across geographic space that, in aggregate, can characterize varietal climatic responses. We present the results of 12,409 farmer-managed experimental plots of common bean (Phaseolus vulgarisL.) in Nicaragua, durum wheat (Triticum durumDesf.) in Ethiopia, and bread wheat (Triticum aestivumL.) in India. Farmers collaborated as citizen scientists, each ranking the performance of three varieties randomly assigned from a larger set. We show that the approach can register known specific effects of climate variation on varietal performance. The prediction of variety performance from seasonal climatic variables was generalizable across growing seasons. We show that these analyses can improve variety recommendations in four aspects: reduction of climate bias, incorporation of seasonal climate forecasts, risk analysis, and geographic extrapolation. Variety recommendations derived from the citizen science trials led to important differences with previous recommendations.

Description: 〈span〉Crystal aggregates in igneous rocks have been variously ascribed to growth processes (e.g., twinning, heterogeneous nucleation, epitaxial growth, dendritic growth), or dynamical processes (e.g., synneusis, accumulation during settling). We tested these hypotheses by quantifying the relative orientation of adjacent crystals using electron backscatter diffraction. Both olivine aggregates from Kīlauea volcano (Hawaiʻi, USA) and chromite aggregates from the Bushveld Complex (South Africa) show diverse attachment geometries inconsistent with growth processes. Near-random attachments in chromite aggregates are consistent with accumulation by settling of individual crystals. Attachment geometries and prominent geochemical differences across grain boundaries in olivine aggregates are indicative of synneusis.〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉Middle Jurassic dinosaur fossils are exceedingly rare, but new discoveries from the Isle of Skye, Scotland, are beginning to fill this gap. We here describe a new dinosaur tracksite found in the Lealt Shale Formation (Bathonian) of the Great Estuarine Group at Rubha nam Brathairean (Brothers' Point) on Skye. The site preserves an abundance of small sauropod manus and pes prints and several isolated and broken medium-to-large tridactyl footprints. The main site occurs on a single horizon of shaley limestone that formed in a lagoonal environment. The sauropod tracks are tentatively assigned to the ichnotaxon 〈span〉Breviparopus〈/span〉 due to the narrow gauge of the trackways, the digital characteristics of the pes, and the ratio of heteropody observed between the manus and the pes. A theropod trackmaker is inferred for some of the tridactyl impressions with several indicative of the ichnotaxon 〈span〉Eubrontes〈/span〉. This new site strengthens the inference, originally based on a previously discovered locality near Duntulm Castle (Duntulm Formation) in northern Skye, that sauropods habitually spent time in lagoons during the Middle Jurassic.〈strong〉Supplementary material〈/strong〉: The photogrammetric model of track BP2_40 and associated metadata and photographs are available at 〈a href="https://doi.org/10.6084/m9.figshare.c.4046390"〉https://doi.org/10.6084/m9.figshare.c.4046390〈/a〉〈/span〉

Description: 〈span〉〈div〉Abstract〈/div〉The Kalkarindji flood basalt province of northern Australia erupted in the mid-Cambrian. Today, the province consists of scattered volcanic and intrusive suites, the largest being the Antrim Plateau Volcanics (APV) in Northern Territory. Accurate dating of the Kalkarindji flood basalt province has proved challenging, with previous studies focused on minor volcanic rocks and intrusive dykes in Northern Territory and Western Australia. These previously published data, corrected to the same decay constants, range from 512.8 to 509.6 ± 2.5 Ma [2σ], placing the Kalkarindji flood basalt province in apparent synchronicity with the Cambrian Stage 4–5 biotic crisis at 510 ± 1 Ma. This study utilizes 〈sup〉40〈/sup〉Ar/〈sup〉39〈/sup〉Ar dating of basalts from the APV to accurately date the major volcanic eruptions in this province. The results yield an age of 508.0–498.3 ± 5.5 Ma [2σ], indicating that the APV is younger than the intrusive rocks. These dates allude to a relative timing discrepancy, where intrusive activity in the North Australian Craton preceded the eruption of the APV as the last magmatic activity in the region. The determination of these largest eruptions to be later than 510 Ma effectively disassociates the Kalkarindji lavas from being a major cause of the 510 Ma biotic crisis, but cannot definitively discount any deleterious effects on the fragile Cambrian ecosystem.〈strong〉Supplementary material〈/strong〉: 〈sup〉40〈/sup〉Ar/〈sup〉39〈/sup〉Ar analysis data tables, XRF geochemical data, alteration study and photomicrographs of all five samples are available at: 〈a href="https://doi.org/10.6084/m9.figshare.c.4176674"〉https://doi.org/10.6084/m9.figshare.c.4176674〈/a〉〈/span〉

Description: 〈span〉The Santa Fe structure in northern New Mexico is one of the few confirmed impact craters in the western USA. The history of the impact structure is obscure as it is tectonized and eroded to the extent that an intact crater is not preserved, and what remains is located in a complex geological setting. Shatter cones and shocked quartz were previously cited to confirm an impact origin; however, estimates for both impact age (350−1200 Ma) and crater diameter (6−13 km) remain poorly constrained. To further evaluate the extent of shock deformation, we investigated ∼6600 detrital zircon grains for shock features, using material collected from 15 drainages and other sites within an ∼5 km radius of known shatter cone outcrops. Six detrital shocked zircon grains were found at three locations, including two near shatter cones and one near brecciated granitoid. Follow-up studies of bedrock at two sites proximal to detrital shocked zircon occurrences led to the discovery of shocked zircon in situ in a shatter cone-bearing sample of biotite schist; shocked grains were not found in brecciated granitoid at the second site. Electron backscatter diffraction confirms the presence of {112} shock-twin lamellae in five shocked zircon grains, and secondary ion mass spectrometry U-Pb data for three detrital shocked grains yielded 〈sup〉207〈/sup〉Pb/〈sup〉206〈/sup〉Pb crystallization ages from 1715 ± 22 to 1472 ± 35 Ma. Laser ablation−inductively coupled plasma−mass spectrometry U-Pb ages for detrital zircon grains at five of the investigated sites provide the first broad constraints on the local distribution of Paleo- to Mesoproterozoic bedrock in the area. The presence of shock-twinned zircon indicates that some exposed rocks at the Santa Fe structure may record impact pressures up to ∼20 GPa based on empirical studies, which is higher than previous reports of ∼10 GPa based on planar deformation features in shocked quartz. The 1472 ± 35 Ma date from a shock-twinned zircon yields the first direct radiometric maximum age constraint on the Santa Fe impact event, and expands the possible time period for impact to the Mesoproterozoic. Identification of shocked zircon in modern sediment led to the first discovery of shocked zircon in bedrock at this site, which is notable, as shocked zircon is otherwise not abundant in the studied rock samples. This study thus illustrates that detrital zircon surveys are an efficient way to search for diagnostic evidence of shock deformation at putative impact structures where shocked minerals may be present, but are not abundant in exposed bedrock.〈/span〉

Description: Cementation of sandstone by minor late barite and sphalerite is widespread in the Scotian Basin at burial depths 〉2 km (〉1 mi), providing information on fluid flow in the basin. The texture and geochemistry of these minerals were analyzed by scanning electron microscopy and electron microprobe on samples from conventional core. Barite and sphalerite postdate silica and carbonate cementation, occurring in veins or occupying secondary porosity. They occur with diagenetic chlorite, kaolinite, pyrite, titania minerals, kutnohorite, and Mn-siderite. This study relates barite and sphalerite to the salt-tectonic evolution of the basin, based on seismic interpretation, and the thermal history of the basin, based on fluid inclusion studies. Barite is readily transported in basinal fluids 〉100°C (212°F), yet is consistently a very late diagenetic mineral. This implies that the source of Ba is because of the late diagenetic breakdown of K-feldspars at 2–3 km (1–2 mi) depth, which is confirmed by covariation of Ba and Rb in sandstones. Sulfur isotope data suggest that the $${\mathrm{SO}}_{4}^{2+}$$ was derived from Argo Formation evaporites that include 1%–7% anhydrite. Sphalerite is mobile only in saline formation water 〉140°C (〉284°F) and requires long-distance transport through sandstones with Zn-rich Fe-Ti oxides. Active detachment faults on salt welds provide potential pathways and a source of salt for migrating formation water. The particularities of source and transport of both barite and sphalerite allow the pathways of basinal fluids and their relationship to active salt tectonics to be inferred, providing indirect dating of the later stages of diagenetic paragenesis corresponding to times of hydrocarbon charge.

Description: Eragrostis tef is an allotetraploid (2n = 4 × = 40) annual, C4 grass with an estimated nuclear genome size of 730 Mbp. It is widely grown in Ethiopia, where it provides basic nutrition...

Description: The origin and causes of mineralogical diversity of A-type granites are debated. The series of A-type granite plutons, with distinct mineralogical differences, emplaced along an Upper Paleozoic crustal-scale shear zone in the Cobequid Highlands, Nova Scotia, provide an opportunity to examine the origin of different A-type plutons in a similar tectonic setting. Based on the ferromagnesian minerals present, the plutons are classified into sodic granites with sodic amphibole, calcic granites with calcic amphibole, and biotite granites. Sodic and calcic granites occur exclusively in complex intrusions with subequal amounts of gabbro in the eastern shear zone, whereas plutons in the western shear zone, with lesser gabbro, are solely biotite granites. Trace elements and radiogenic isotopes show that the three granite types have different sources. Intensive parameters including temperature, pressure, and water-in-melt contents were estimated from mineralogical and geochemical data. Modeling of these geochemical data suggests that the biotite and calcic granites were derived by 20%–40% partial melting of intracrustal feldspathic rocks, whereas the sodic granites are extreme fractionates (90%) of coeval mafic magma. We propose that supply of Upper Paleozoic mafic magma, probably related to regional extension and decompression melting beneath the Magdalen Basin, created a deep crustal hot zone in the eastern Cobequid Highlands, and extreme fractionation of underplated mafic sills produced the sodic granites. Heat transfer from crystallizing mafic magma induced partial melting of the surrounding crust, creating batches of biotite and calcic granitic melts in different depths. Fractionated and crustally derived melts segregated along crustal-scale faults, constructing the complex plutons in the east. Melting of the crust was further facilitated by the release of water from the crustal rocks upon heating. In the eastern shear zone, water was released predominantly by magmatic rocks and in lesser amounts compared to the west, where Neoproterozoic sedimentary and volcaniclastic rocks are more abundant. The volatile-rich granitic melts in the western part of the shear zone were crystallized rapidly, stabilizing only biotite. This study demonstrates that the mineralogical variations in A-type granites arise from rather similar magma compositions, but they are important petrogenetic indicators of varying sources, specific magmatic processes, and emplacement conditions.

Description: Abstract Climate change is of major relevance to wine production as most of the wine‐growing regions of the world are located within relatively narrow latitudinal bands with average growing‐season temperatures limited to 13–21 °C. This study focuses on the incidence of climate variables and indices that are relevant both for climate change assessment and for grape production, with emphasis on grapevine bioclimatic indices and extreme events (e.g. cold waves, storms, heatwaves). Dynamical downscaling of European Reanalysis‐Interim (ERA‐Interim) and Max Planck Institute Earth System low‐resolution (MPI‐ESM‐LR) global simulations forced with a Representative Concentration Pathway 8.5 (RCP8.5) greenhouse gas (GHG) emission scenario was performed with the Weather Research and Forecast (WRF) model to a regional scale including the Douro Valley of Portugal for recent‐past (1986–2005) and future periods (2046–2065, 2081–2100). The number, duration and intensity of events were superimposed over critical phenological phases estimated by using a specific local grapevine varietal phenological model in order to assess their positive or negative implications for wine production in the region. An assessment of the relevance of climate parameters and indices and their progression in recent‐past and future climate scenarios with regard to the potential impact on wine production was performed. Results indicate a positive relation between higher growing‐season heat accumulations and greater vintage yields. A moderate incidence of very hot days (daily maximum temperature above 35 °C) and drought from pre‐véraison phenological conditions have a positive association with vintage ratings. However, the mid‐ and long‐term WRF‐MPI RCP8.5 future climate scenarios reveal shifts to warmer and drier conditions, with the mean growing‐season temperature (GST) not remaining within range for quality wine production in the long‐term future climate scenario. These results indicate potential impacts that suggest a range of strategies to maintain wine production and quality in the region.

Description: Abstract The Petrified Forest of Lesbos comprises silicified tree fossils at multiple stratigraphic levels within the Lower Miocene Sigri Pyroclastic Formation. Our objective was to understand the interplay of tectonic setting, structural evolution, volcanological setting and basin evolution in the preservation of this remarkable natural monument. Sections were logged for lithology, sedimentary structures and hydrothermal alteration. Orientations of fallen fossil trees were measured. Samples were taken for mineralogical and geochemical analysis. 40Ar/39Ar dating was carried out on mineral separates from four samples. Widespread andesite‐dacite domes, the Eressos Formation, intrude and overlie metamorphic basement and are overlain by the Sigri Pyroclastic Formation, which comprises several hundreds of metres of pyroclastic flow tuffs (unwelded ignimbrites) interbedded with fluvial conglomerate and volcaniclastic sandstone. The Sigri Pyroclastic Formation ranges in age from 21.5 to 22 Ma, where it overlies the lacustrine Gavathas Formation, to younger than 18.4 Ma. Tuffs and fluvial conglomerates in the Sigri Pyroclastic Formation coarsen eastwards, and petrified trees and soil horizons occur throughout the Formation. The recurrence of pyroclastic flows was approximately one every 20 ka, so destructive flows were relatively infrequent, allowing the development of climax vegetation between most eruptions. Conglomerate‐filled channels show that rivers flowed westwards. Tree fall directions indicate NW to N movement of pyroclastic flows, implying a source near the younger Mesotopos–Tavari caldera to the south. The basin, which formed in a NNE‐trending dextral strike‐slip regime, provided some topographic steering. Following the Sigri Pyroclastic Formation at ca. 18 Ma, there was a rapid increase in the pace of volcanic activity, with the eruption of thick lava sequences and welded ignimbrites, and intrusion of dykes and laccoliths in SW Lesbos. Rapid burial by permeable tuffs, silica from alteration of volcanic ash, and later hydrothermal circulation all contributed to the preservation of the petrified trees.