Volcanic Plains Research Articles

Evidence for geologically recent explosive volcanism in Elysium Planitia, Mars

Volcanic activity on Mars peaked during the Noachian and Hesperian periods but has continued since then in isolated locales. Elysium Planitia hosts numerous young, fissure-fed flood lavas with ages ranging from approximately 500 to 2.5 million years (Ma). We present evidence for a fine-grained unit that is atypical of aeolian deposits in the region and may be the youngest volcanic deposit yet documented on Mars. The unit has a low albedo, high thermal inertia, includes high‑calcium pyroxene-rich material, and is distributed symmetrically around a segment of the Cerberus Fossae fissure system in Elysium Planitia. This deposit is superficially similar to features interpreted as pyroclastic deposits on the Moon and Mercury. Unlike previously documented lava flows in Elysium Planitia, this feature is morphologically consistent with a fissure-fed pyroclastic deposit, mantling the surrounding lava flows with a thickness on the order of tens of cm over most of the deposit and a volume of 1.1–2.8 × 107 m3. Thickness and volume estimates are consistent with tephra deposits on Earth. Stratigraphic relationships indicate a relative age younger than the surrounding volcanic plains and the Zunil impact crater (~0.1–1 Ma), with crater counting suggesting that the deposit has an absolute model age of 53 ± 7 to 210 ± 12 ka. This young age implies that if this deposit is volcanic then the Cerberus Fossae region may not be extinct and that Mars may still be volcanically active. This interpretation is consistent with the identification of seismicity in this region by the Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander, and has additional implications for astrobiology.

Vortex‐Dominated Aeolian Activity at InSight's Landing Site, Part 2: Local Meteorology, Transport Dynamics, and Model Analysis

AbstractGeologic and climatic processes on modern‐day Mars are heavily influenced by aeolian surface activity, yet the relationship between atmospheric conditions and sediment mobilization is not well understood. The Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) spacecraft is uniquely able to address this issue, due to its joint imaging and continuous high‐frequency meteorological capabilities, which allow for direct comparison between surface activity and atmospheric conditions. Since landing in the volcanic plains of Elysium Planitia, InSight's camera's have recorded intermittent, small‐scale surface changes, including removal of fine material on the lander footpad, linear tracks and localized surface darkening caused by minor dust removal, and surface creep of granules, as presented in Part 1 (Charalambous et al., 2021, this issue). Surface activity is found to correlate well with the timing of abrupt pressure drops (ΔP ∼ 1–9 Pa) and transient wind gusts (v ∼ 14–31 m/s) associated with convective vortex passage. Here we identify the major erosive forces acting on surface particles during these events, including the vertical pressure gradient force at the vortex core and the drag force generated by quickly‐rotating tangential winds. Orbital and ground‐truth data suggest that aeolian activity at InSight's landing site is sporadic under modern climatic conditions. Ongoing aeolian surface modifcation is driven primarily by turbulent vortices that sporadically lift dust and redistribute coarser sediment (i.e., sand and granules) but do not aid in the development of organized aeolian bedforms. Surface erosion is localized within the path these vortices take across the surface which is controlled by seasonally‐reversing background circulation patterns.

Degassing of volcanic extrusives on Mercury: Potential contributions to transient atmospheres and buried polar deposits

The surface of Mercury is dominated by extensive, widespread lava plains that formed early in its history. The emplacement of these lavas was accompanied by the release of magmatic volatiles, the bulk of which were lost to space via thermal escape and/or photodissociation. Here we consider the fate of these erupted volatiles by quantifying the volumes of erupted volcanic plains and estimating the associated masses of erupted volatiles. The concentrations and speciation of volatiles in Mercury's magmas are not known with certainty at this time, so we model a wide range of cases, based on existing experimental data and speciation models, at 3–7 log fO2 units below conditions determined by the iron-wüstite buffer. Cases range from relatively low gas content scenarios (total exsolved gas mass of 9×1015 kg) to high gas content scenarios (total exsolved gas = 5 × 1019 kg). We estimate that the average duration of a transient volcanic atmosphere resulting from a single eruption would be between ∼250 and ∼210,000 years, depending on the volume, degassed volatile content, and eruption rate of an individual eruption, as well as the fO2 conditions of the planet's interior. If a dense transient atmosphere was ever surface-bound long enough for the released volatiles to be transported to and cold-trapped at Mercury's polar regions, those trapped volatiles are predicted to be well-mixed with the regolith, and at least 16 m beneath the surface given regolith gardening rates. These volatiles would have a composition and age distinctly different from those of the H2O-ice deposits observed at the poles of Mercury today.

Evolution of Jurassic intertrap deposits in the Parnaíba Basin, northern Brazil: The last sediment-lava interaction linked to the CAMP in West Gondwana

The opening of the Central Atlantic Ocean was accompanied by ascending plume zones that generated large igneous provinces (LIPs), such as the Central Atlantic Magmatic Province (CAMP), with voluminous lava flows and outpourings. One of the best records of the CAMP in the West Gondwana is the Jurassic volcanic-sedimentary succession exposed in the western Parnaíba Basin, northern Brazil. Diagenetic and hydrothermal processes are discussed, focusing on the lava-sediment interaction. The siliciclastic sediments called “intertrap deposits” record a wet desert system characterized by fluvial-aeolian and shallow lake deposits engulfed by lavas of the CAMP at approximately 200–202 Ma. The facies and petrographic studies, based on a drill core and outcrops, led to the interpretation of the palaeoenvironmental and diagenetic evolution of the intertrap deposits. The intertrap deposits are sandwiched by basalts and may be organized in seven sedimentary facies, grouped into two facies associations: 1) ephemeral braided river deposits (FA1), which consist of medium- to coarse-grained pebbly sandstone with poorly sorted angular to sub-rounded grains (basaltic fragments and quartz) and low-angle cross-bedding, even-parallel stratification, and trough cross-stratification, and 2) pond/shallow lake deposits (FA2) composed of tabular beds of sandstone/siltstone rhythmite and laminated mudstone. The main architectural elements of intertrap deposits are 1) channels on volcanic substrate, 2) sand sheets deposited over pre-existent lava topography, 3) tabular beds with laminated rhythmites, and 4) sand-filled fissures/fractures and clastic dykes. The intensification of magmatic processes due to the disruption of Pangaea promoted the formation of extensive volcanic plains, whereas wet desert settings were developed during the quiescent intervals between lava flow episodes. Fluvial channels with subaqueous dunes and sand sheets were incised into the basaltic substrate. The abandoned fluvial plains were affected by flash floods that promoted mechanical infiltration of clays, forming coatings over grains. The heat flow and hydrothermal activity of volcanic rocks increased the devitrification of glassy clasts, releasing silica and precipitating low-temperature authigenic mineral assemblages. The most common pore-filling process was the massive precipitation of early diagenetic-hydrothermal minerals, including smectite, chalcedony, poikilotopic zeolite, megaquartz, and haematite, which partially obliterated the primary porosity and permeability. These exceptional conditions of cementation triggered by basalt eruptions precluded the modification of a primary framework by late stages (post-Jurassic) burial diagenesis. The intertrap sandstones represent the last lava-sediment interaction related to the CAMP recorded in West Gondwana.

The assemblage of birds struck by aircraft differs among nearby airports in the same bioregion

Abstract Context Bird–aircraft collisions impose an economic cost and safety risk, yet ecological studies that inform bird hazard management are few, and to date no study has formally compared species’ strike profiles across airports. In response to strike risks, airports have implemented customised management on an airport-by-airport basis, based on the assumption that strike risk stems from prevailing local circumstances. We tested this assumption by comparing a decade of wildlife–aircraft strikes at three airports situated in the same bioregion (likely to have similar fauna) of Victoria, Australia. Aim To compare the assemblage of wildlife struck by aircraft at three major airports in the same bioregion. Method Standardised wildlife strike data were analysed from three airports (Avalon, Melbourne and Essendon Airports), in the Victorian Volcanic Plains bioregion, central Victoria, Australia. Ten discrete 1-year sampling periods from each airport were compared, spanning the period 2009–19. Bird data were comparable, and data on mammals were considered less reliable, so emphasis was placed on birds in the present study. Results In total, 580 bird strikes were analysed, with the most commonly struck species being Australian magpie (Cracticus tibicen; 16.7%), Eurasian skylark (Alauda arvensis; 12.2%), Australian pipit (Anthus australis; 12.1%), masked lapwing (Vanellus miles; 5.9%), nankeen kestrel (Falco cenchroides; 5.0%), house sparrow (Passer domesticus; 4.8%), welcome swallow (Hirundo neoxena; 4.3%) and tree martin (Petrochelidon nigricans; 4.0%). The assemblage of birds struck by aircraft over the decade of study differed between airports. The most commonly struck species drove the assemblage differences between airports. Conclusions and implications In the present study system, airports experienced discrete strike risk profiles, even though they are in the same bioregion. The airports examined differed in terms of air traffic movement rates, aircraft types, landscape context and bird hazard management effort. Given that strike risks profiles differ among airports, customised management at each airport, as is currently the case, is supported.

Tesserae on Venus may preserve evidence of fluvial erosion

Fluvial erosion is usually assumed to be absent on Venus, precluded by a high surface temperature of ~450 °C and supported by extensive uneroded volcanic flows. However, recent global circulation models suggest the possibility of Earth-like climatic conditions on Venus for much of its earlier history, prior to catastrophic runaway greenhouse warming. We observe that the stratigraphically oldest, geologically most complex units, tesserae, exhibit valley patterns morphologically similar to the patterns resulting from fluvial erosion on Earth. Given poor topographic resolution, we use an indirect technique to recognize valleys, based on the pattern of lava flooding of tesserae margins by adjacent plains volcanism. These observed valley patterns are attributed to primary geology, tectonic deformation, followed by fluvial erosion (and lesser wind erosion). This proposed fluvial erosion in tesserae provides support for climate models for a cool, wet climate on early Venus and could be an attractive research theme for future Venus missions.

THE CHARACTERISTICS OF INFILTRATION ON THE SOUTHERN FLANK OF MERAPI VOLCANIC PLAIN, YOGYAKARTA, INDONESIA

The broad development of built areas has decreased infiltration areas, which in turn gives impacts on water table subsidence. The infiltration capacity and distribution are factors that need to consider in preserving the groundwater. This research aims to examine the infiltration rate, infiltration capacity, and distribution of potential infiltration on the southern flank of the volcanic foot plain and the fluvial-volcanic plain of Merapi Volcano. The method employed in this research is a direct measurement using a double-ring infiltro-meter. The constant infiltration rate was analyzed using the Horton Method. The results show that the high infiltration rate spreads over an area with an altitude of less than 200 Meter Above Mean Sea Level (MAMSL) which has very deep groundwater. Meanwhile, the infiltration rates above 200 MAMSL tend to be smaller in shallower groundwater depths. The infiltration capacity in the research area tends to be high. The highest infiltration rate is 1.2 cm/minute with the infiltration equation of ft = 1.20 + (1.967-1.20)e - 0.0492t, while the lowest infiltration rate is 0.1 cm/minute with the infiltration equation of ft = 0.10 + (0.149-0.10)e -0.0396t. Most of the research areas have moderate or fairly rapid infiltration capacity that spreads from areas below 200 MAMSL to the top altitude at 400 MAMSL. The potential for water infiltration in the research area mostly belongs to the medium category. Overall, this paper presents new insights to understand the characteristics of infiltration in volcanic plain related to the development of land use.

Basaltic fissure types on Earth: Suitable analogs to evaluate the origins of volcanic terrains on the Moon and Mars?

Basaltic eruptive fissures of the Great Rift and surroundings on the eastern Snake River Plain of Idaho, USA, and selected volcanic features in Hawai’i, Iceland and northern Africa were surveyed for their relevancy as planetary analogs. Evaluated during field investigations and in satellite imagery for structures, physiography, and geologic setting, fissures were categorized into four broad types: (1) simple, monogenetic fissures with obvious volcanic constructs or deposits, (2) monogenetic fissures now obscured by low shields or relatively large cones, (3) polygenetic volcanic rift zones with multiple vents and deposits, and (4) compound regional fissure systems or dike swarms that comprise major rift zones or large volcanic terrains. Using this classification as an initial base, we surveyed imagery of volcanic features for likely fissure vents in two major geologic settings on the Moon: floor-fractured craters (FFCs) and mare and cryptomare provinces. Two major regions on Mars, the volcanic plains around Alba Mons and the greater Tharsis region, were also surveyed for fissure types and volcanic associations of fissure-like features. The planetary surveys suggest that the proposed classification provides a suitable analog starting point to interpret structures associated with fissure systems on the Moon and Mars.With few exceptions, our survey indicates that each of the studied terrains exhibits a dominant fissure type. Type 1 fissures, most with pyroclastic deposits, prevail in lunar FFCs and mare-like regions; whereas type 2 fissures are ubiquitous in the Tharsis region of Mars and a few exist on the Moon as low shields. Type 3 volcanic rift zones are not common on either the Moon or Mars, although they might become evident in future work on chemically evolved terrains. Type 4 fissures are inferred in mare terrains, often represented as the extensions of major linear rille networks or rimae, with possibly complex dike swarms that were buried beneath voluminous mare basalt lava flows. Likewise, numerous flood lavas on Mars are possibly associated with now-obscured or difficult to define type 4 fissure systems.

Comparison of InSight Homestead Hollow to Hollows at the Spirit Landing Site

AbstractThe InSight spacecraft landed within an ~27‐m diameter highly degraded impact crater, informally called Homestead hollow, that was disturbed during landing by pulsed retrorockets that blew out dust and scoured loose sand around the landing site. In order to provide insight into what the surface of Homestead hollow originally looked like before landing and to further characterize hollow physical properties, we examined images of similar hollows taken by the Spirit rover at the Gusev landing site. Hollows at both sites are characterized by a quasi‐circular appearance with little or no crater rim still visible and a bright interior with fewer and smaller rock sizes relative to the surrounding plains. Resolvable clast lengths (>2 mm) measured in Laguna hollow at the Spirit site and Homestead hollow are comparable with most clasts between 3 and 7 mm in length. Measurements of clast shapes show that those in Laguna hollow are slightly more elongate relative to those in Homestead hollow, although this may be an artifact of the differing viewing geometry and (or) a thicker dust mantle obscuring the full shape of clasts at Laguna hollow. The soils at both hollows show evidence for cohesion and a duricrust, with a trench dug at Laguna hollow and pits exposed at Homestead hollow exhibiting steep slopes, overhanging layers, and clods of soils. The similarities in morphology and physical properties of hollows at two different landing sites suggest recent environmental conditions that degrade and infill impact craters are comparable and pervasive for equatorial volcanic plains on Mars.

Mercury's Crustal Thickness Correlates With Lateral Variations in Mantle Melt Production

AbstractOver the first billion years of Mercury's history, mantle melting and surface volcanism produced a secondary magmatic crust varying spatially in composition and mineralogy. By combining geochemical mapping from MESSENGER with laboratory experiments on partial melting, we translate the surface mineralogy into lateral variations of surface density and calculate the degree of mantle melting required to produce surface rocks. If lateral density variations extend through the whole crust, the local crustal thickness correlates well with the degree of mantle melting. Low‐degree mantle melting produced a thin crust below the northern volcanic plains (19±3 km), whereas high‐degree melting produced the thickest crust in the ancient high‐Mg region (50±12 km), refuting the hypothesis of an impact origin for that region. The thickness‐melting correlation has also been observed for the oceanic crust on Earth and might be a common feature of secondary crust formation on terrestrial planets.

Dominant C3 tussock grasses are resilient to the re‐introduction of fire in long‐unburned temperate grasslands

AbstractQuestionsThe recovery of dominant tussock grasses following fire is crucial as they contribute disproportionately to the structure and function of grasslands. To determine how resilient native grasslands are to the re‐introduction of fire, we quantify how fire affects the resprouting of the dominant C3 tussock grasses in long‐unburned grasslands (Austrostipa spp.) and compare this to the recovery of C4 tussock grasses (Themeda triandra) in grasslands that have had regular exposure to fire. We also quantify if these two grassland types burn in different ways as a result of their different dominant grass compositions.LocationTemperate native tussock grasslands on the Victorian volcanic plain, Australia.MethodsTo determine how fire affects tussock mortality, and whether this differs between C4 (regularly ) and C3 (long‐unburned) grasslands, tussocks were permanently marked pre‐fire and re‐censused for survival and growth at seven weeks after fire. To assess whether C3 grasslands burn in a different way to C4 grasslands, fire behaviour was quantified at 11 sites.ResultsFire behaviour was similar in both grassland types. Both C3 and C4 grass tussocks were resilient to fire, despite decades of fire suppression in C3 grasslands. Tussock mortality was low (<5%) in both C3 and C4 grasses. Survival was independent of basal circumference in C4 Themeda tussocks, but smaller‐sized tussocks (<10 cm circumference) were less likely to survive fire in C3 Austrostipa grasslands. Basal area declined in both grasses after fire but rate of tiller regrowth after fire was similar for both grass types.ConclusionLong‐unburned C3 grass tussocks were resilient to a single fire. Future studies should examine the response of C3 grasses to a fire regime that comprises frequent return intervals to which C4 grasses are resilient; this may indicate whether C3 grasses are sensitive to short fire‐return intervals despite resilience to an individual fire event.

Taphonomy of lacustrine fish fossils of the Parnaíba Basin, northeastern Brazil: Spatial and causative relations of Konservat Lagerstätten in West Gondwana during Jurassic-Cretaceous

Fossil bonanzas called Konservat Lagerstätten provide geological windows to the ecology of ancient life communities. These deposits often occur as cluster of fossil localities with similar geographic locations, geological ages and facies, as the fossils were generally preserved during special periods and large-scale events in Earth history within environments with exceptional taphonomic conditions. This work applied petrological and geochemical analyses to evaluate the taphonomic pathway of a Konservat Lagerstätten in the Muzinho Shale, Upper Jurassic-Lower Cretaceous of the Parnaíba Basin, northeastern Brazil. These lacustrine deposits include interbedded limestones and fossiliferous black shales deposited in anoxic, non-euxinic and saline environment. Black shales contain articulated skeletons of fish fossils, characterised by three-dimensional preservation of the skeletal tissue. The polytypical assemblage includes diverse ontogenetic stages and is concentrated in a specific stratigraphic level. Mass mortality was triggered by anoxia probably established by stratified water column, high C flux and thermocline demise. The specimens are encased in kerogen-bearing siliciclastic laminae and cementstone microfacies, both microbially-induced. The fossils were cemented by eodiagenetic poikilotopic calcite that filled the skeletal articulation, including bone trabeculae and voids originally filled by bone marrow. The short distance, similar fossil assemblages, ages and coincident palaeoenvironments suggest that Muzinho Shale (Parnaíba Basin) and Crato Formation (Araripe Basin) compose a cluster of exceptional preservation in West Gondwana. Lava flows and outgassing related to the Central Atlantic Magmatic Province (CAMP) resulted in the subaereal exposure of volcanic plains, acid rains and subsequent CO2 greenhouse crisis. CAMP-magmatism was especially voluminous in northern Brazilian basins, enhancing nutrient-rich waters and lacustrine eutrophication due to intensified chemical weathering in this area. Probably, other Konservat Lagerstätten remain unreported in West Gondwana. Despite similar causative events, the individual taphonomic pathways of Muzinho Shale and Crato Formation are very different, suggesting that in these cases local phenomena affected authigenesis and diagenesis.

Multistage ice-damming of volcanic flows and fluvial systems in Northeast Syrtis Major

The northeast edge of the Syrtis Major volcanic complex records a diverse history of volcanism and climate of early Mars which has long been argued to be dominated by icy or wet conditions. This region contains a stratigraphic record that spans the period of phyllosilicate secondary mineralogy from moderate pH alteration of the Early Noachian crust, to the more acidic, sulfate-forming, Hesperian period dominated by the adjacent volcanic plains of Syrtis Major Planum. A paleo-fluvial basin and channel system etched in the Syrtis Major volcanics is identified and analyzed using multiple instruments onboard the Mars Reconnaissance Orbiter. These observations and analysis link the current landscape and the basin's existence at the base of the Syrtis Major lava flow to a paleo-glaciation within the Isidis Basin. This paleo-glaciation formed ice sheets kilometers thick and ranged over hundreds of kilometers laterally and is responsible for halting the Syrtis Major flows in the Northeast Syrtis area to form the observed steep cliffs and the topographically flat mesa. Following this large scale glaciation, channels fed primarily by precipitation were etched into the Hesperian volcanics before filling the basin and flowing out an area of higher topography than is currently available due to the existence of an episodic ice dam before terminating in a potential, highly eroded, fan. The dynamic relationship between the climate and landscape evolution has left an imprint on the local geologic record of this complex region of Mars, with testable observations that could be made with the Mars 2020 Rover in the form of a highly jointed surface formed from lava ice interactions on the cliff face of the volcanic mesa.

Geomorphological Characteristic of Landslide Hazard Zones in Sukarame Village, Cisolok Subdistric, Sukabumi Regency

Geomorphology is the study of landforms, the processes of its formation, and the relations between forms and processes in their spatial order. Landslide is the movement of a mass of rock or earth from a higher place to a lower level due to the interaction of the geology structures, hydrology, and geomorphology. In a geomorphological unit, various aspects actively control the occurrence of ground movements. Knowing the geomorphological characteristics is crucial to identify a large estimation of the potential for landslides in the region. The Village of Sukarame is one of the villages in the Sukabumi Regency located on the slopes of Mount Halimun, whose territory is divided into west and east, separated by the Cisukarame River. Mapping the required geomorphological units Digital Data Elevation Model Indonesia (DEMNas) from the Geospatial Information Agency (BIG) is processed for altitude and slope data, as well as geological data and river data collected from BIG. Verification of landslide events through interviews and field surveys geomorphological unit analysis is done by overlaying and comparing the results of field observations. Also, a descriptive analysis is conducted by observing the map of landslide hazards zone from INARisk. The results show that the Village of Sukarame materialized from volcanic and fluvial origins. It has nine geomorphological units, which are the Hill Intrusion, Floodplain, Tapos Breccia Volcanic Plain, Citorek Tuff Volcanic Plain, Halimun Lava Slope, Tapos Breccia Slope, Citorek Tuff Slope, Fumaroles Plain, and Halimun Lava Field. Landslide-prone areas in Sukarame are in the geomorphological unit of Hill Intrusion, east of Halimun Lava Slope, Citorek Tuff Volcanic Plain, and along the river cliffs of the Cisukarame River and Cimaja River. The landslides occur naturally on the river cliffs of Floodplain and the cliffs of Citorek Tuff Volcanic Plain, which are dominated by sediments that cause the soil surface to become unstable. Moreover, anthropogenic activities, such as mining in the Hill Intrusion, also affect landslide occurrence in Sukarame.

Implementation of the SMORPH method for mapping the susceptibility area of landslide in Bogor City

This study aims to map landslide susceptibility areas in Bogor City. The method used is the modified SMORPH method. the main parameters in this method are the slope angle and slope shape. Calculation of slope shape using curvature algorithm. The results showed that the widest medium and high hazard classes were in the South Bogor Subdistrict with a percentage reaching 46.14%. This is because most of the area is the lower slope of denudational volcanic cones and river cliffs. Medium and high hazards with the lowest area are in East Bogor Subdistrict, where the dominance of the area is the volvio volcanic plain covering an area of 70.41% of the total area.

Analytical Identification and Characterization of the Major Geochemical Terranes of Mercury's Northern Hemisphere

AbstractPrincipal component analysis of Mercury chemical composition maps provide analytically robust identification of distinct geochemical terranes on Mercury. The results reveal a wide diversity of terrane types, including previously identified terranes like the high‐Mg terrane and northern terranes, as well as a new terrane not identified in prior studies, the intermediate composition, high‐K (IHK) terrane. We propose that the IHK is material excavated from beneath the Borealis planitia by the Rustaveli‐basin‐forming impact. In addition to the new IHK terrane, Caloris‐basin‐like materials are recognized outside of the basin rim for the first time. This indicates that the terrane type found within the Caloris basin is not a unique consequence of the Caloris impact event. Geochemical modeling of terrane compositions facilitates interpretation of the principal components in terms of mineral end‐members, making the individual principal component maps also a measure of the relative variability of pyroxenes, olivine, and plagioclase. Our mineralogical modeling also confirms the low‐viscosity nature of the lava that flooded Mercury's surface to produce the present‐day crust, consistent with the geomorphology of Mercury's extensive volcanic plains units.

Potensi Batugamping Untuk Bahan Baku Industri Semen Daerah Biluhu Timur Dan Sekitarnya

Limestone is a sedimentary rock composed by calcium carbonate derived from the rest of marine organisms and the main materials of cement so exploration and calculation of limestone resources need to be done. The research area is administratively located at the Biluhu Timur Village and its surroundings, Batudaa Pantai District, Gorontalo Regency. The purpose of this study is to observe the geological conditions of the study area to determine distribution of limestones in the study area to be used as cement industrial materials with the geological mapping, and the analysis limestone geochemical using XRF (X-Ray Flourescence). Based on the result of this research can be concluded that the research area was devided into four geomorphological units, consisting of volcanic hills unit, denudational hills and plain unit, and the coastal plain unit. The litology arranged by granodiorit, basal, and the limestone (packstone and wackestone). Based on the result of geochemical analysis using XRF and calculation of volume using Surpac softwere can be devided into three blocks. The A block have limestones (packstone) with the content of CaO 51.79% and MgO 1.98% that meets the requirement materials of portland cement with total volume 423 107 230 tons. The B block have limestones (wackestone) with the content of CaO 4.92% and MgO 5.28% that not meets the requirement materials of portland cement with total volume 729 263 008 tons. The C block have limestones (packstone) with the content of CaO 52.85% and MgO 0.98% that meets the requirement materials of portland cement with total volume 539 883 150 tons.

Evolution of the Navua Valles region: Implications for Mars' paleoclimatic history

The Navua Valles are comprised of a system of channels and valleys on the inner Northeastern rim of Hellas Basin, which is a 1500-km-long sloping terrain. Drainage systems and regional geology in this unique setting were not previously mapped in detail. We mapped this region using CTX (6 m/px) as the base map and assessed surface unit ages resulting from our crater counting. We found that the timing of the deposit-forming episodes in this region during the Hesperian and Early to Middle Amazonian largely correlated to active phases of the Hadriacus Mons volcanic center. We found evidence for several episodes of fluvial activity Hesperian to the Amazonian with declining intensity, and transitioning to ice-dominated processes. The channels in the Navua Valles region erode into deposits dating from the Noachian to Early Amazonian, including the Noachian highlands, Noachian to early Amazonian crater ejecta, and likely volcanic plains formed from the Hesperian to the Hesperian–Amazonian transition. Channels directly originating from Hadriacus Mons are younger, while precipitation-fed channels at larger distance from the volcanic center are older, indicating different triggers for fluvial activity. Crater counting results indicate that almost all channel floors were at least partially resurfaced during the Amazonian and that several channel deposits formed during the last 0.5 Gyr. Water pathways likely included surface channels, lakes, and subsurface flow. The Navua Valles channel system is discontinuous, and the number of terminal deposits (sink locations) is almost as high as the number of channel sources, which is unusual for valley networks elsewhere on Mars. Interior channels formed only in the major Navua channels, they are even more fragmented than their parent channels, but occur along their entire length. Channels and valley systems within the Navua Valles are potential targets for in situ astrobiological studies, as they could have provided potential habitats at least periodically, from the Late Hesperian to the Late Amazonian.

Equilibrium crystallization modeling of Venusian lava flows incorporating data with large geochemical uncertainties

Our understanding of the Venusian surface composition is limited to the in-situ bulk rock chemical analyses collected by the Vega and Venera missions. However, these analyses have exceedingly large analytical uncertainties – up to 50% by weight (1σ) for certain oxide components. In this study, we use the Venera 14 lander data and apply a Monte Carlo approach to assess how significant uncertainties affect modeling of lava solidification. Thermodynamic modeling of mineral-melt equilibria is conducted over 1,000 iterations of simulated bulk composition within the Gaussian probabilistic bounds of the reported analytical uncertainty along a cooling path from 1350°C to 950°C, with a fixed pressure of 90 bars. The results are used to calculate melt and apparent viscosity (ηmelt and ηapp, respectively). Despite the significant analytical uncertainty of the lander data, lava viscosity is tightly constrained. Mean log ηmelt increases from 1.65 ± 0.46 Pas at 1350°C to 8.57 ± 1.42 Pas at 950°C (1σ). Log ηapp is less well-defined due to increased scatter in crystal fraction with solidification, increasing to 17.7 ± 1.3 Pas at 950°C (γ=10−6 s−1). A significant increase in ηapp occurs between 1240°C and 1080°C due to a rapid increase in crystal mass fraction (Φ increases from ∼0.05 at 1250°C to 0.8 at ∼1100°C). Slow cooling through this 150°C window must occur so as to not drastically increase lava viscosity and impede flow. These results show that despite limited geochemical data and large analytical uncertainties, reasonable constraints for the physical and chemical evolution of lava solidification can be obtained. Most of the Venusian surface is composed of volcanic plains and rises, containing abundant landforms characteristic of fluid basaltic lava. Our results provide new insights into the crystallization processes in Venusian lava flows, which are fundamental for understanding Venusian igneous processes, geodynamics, and resurfacing. This work provides a necessary framework for future thermorheological flow models to determine flow volume and effusion rates.

Genesis of poikilotopic zeolite in aeolianites: An example from the Parnaíba Basin, NE Brazil

Zeolite cement is one of the main components of the Jurassic to Lower Cretaceous fluvial-aeolian succession in the Parnaiba Basin, northeastern Brazil. Core and outcrop-based stratigraphic analyses permitted the paleo-environmental and diagenetic interpretation of aeolian sandstone and showed the influence of the volcanic substrate in the origin of the zeolite cement. The substrate is represented by an extensive volcanic plain developed in the last stages of the Central Atlantic Magmatic Province (CAMP) in West Gondwana. The siliciclastic deposits consist of dune field, sand sheet and wadi deposit facies associations. The zeolite cement of the aeolian succession forms poikilotopic crystals with anomalous up to 50% modal content. X-ray diffraction and SEM/EDS/CL analyses showed laumontite and Ca-stilbite exhibiting, respectively, massive and radial textures. During eodiagenesis, the main processes included clay infiltration linked to water table fluctuations and flash flood events, producing clay coatings and displacive stilbite cementation. Massive laumontite cementation and smectite-chlorite conversion occurred in the mesodiagenesis, while in the final stages, the zeolite was partially replaced by calcite cement. Telodiagenesis is recorded by iron exsudation and the corrosion of clay films. Several processes can be inferred to explain the origin of the zeolite cement in the Jurassic-Lower Cretaceous sandstone of the Parnaiba Basin. After the first magmatic pulse (Triassic magmatism), the zeolite-bearing basalts were submitted to chemical weathering, causing cation leaching. Afterwards, the deposition of aeolian sands related to a wet desert system occurred above this weathered substrate. Fractured basaltic substrate favored the release of ions to the surface, with fluids enriched in sodium and calcium that percolated the permeable aeolian sandstone beds during the diagenesis. Furthermore, zeolite cement is geographically associated with the volcanic substrate in the western Parnaíba Basin. However, it is absent in the eastern part, where the aeolianites overlie sedimentary rocks. We suggest that the system was thermally reactivated by the last thermal CAMP phase, with basalt emplacement in the eastern Parnaiba Basin linked to the opening of the Equatorial Atlantic Ocean (Cretaceous magmatism). The progressive heating towards the western part of the basin triggered fluids convection, and the enrichment in ions such as Ca2+, Si4+, Na+, Al3+, HCO−3 and SO42−, promoting optimal conditions for zeolite crystal growth (100 °C–300 °C). Sandstone textural aspects, as well as extensional faults and fractures allowed fluids migration resulting in the massive poikilotopic zeolite cementation, characterizing one of the most singular features of the diagenetic history of the West Gondwana record.