Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100039
Amit Tiwari , S.L. Memory , Joe Joseph , R.R. Meshram
The Eocene Kopili Formation in the Assam foreland basin records sediment sources, tectonic activity and depositional environments following the India-Eurasia collision. Mineralogical and geochemical analysis of these shales exposed near Garampani, Assam, NE India was conducted to study the diagenesis, palaeoweathering, palaeosalinity, redox conditions, tectonic settings and provenance. The Kopili Formation is composed of mainly shale with thin beds of limestone, black shale and sandstone and these units overlie the Upper Sylhet Limestone. The presence of goethite-rich phosphatic nodules, secondary precipitation within the fissile planes of shale and the occurrence of anatase, talc, smectite and chlorite suggest diagenesis. The prevalence of kaolinite and mean Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Al2O3/MgO and Rb/Sr values of 86.73, 97.26, 16.36 and 1.32, respectively indicates extensive source rock weathering in humid tropical climate. The Index of Compositional Variation (ICV) values ranging between 0.47 and 2.38 also signify high weathering and tectonically active basin. The Sr/Ba ratio 0.34 ± 0.27 (mean±2σ) suggest overall freshwater basin. The Ni/Co (2.84 ± 2.29), V/Cr (1.65 ± 0.45) and Ce/Ce∗ (0.97 ± 0.63) suggest fluctuating redox environment. The samples predominantly cluster in continental island arc domain on the Th-Sc-Zr/10, La-Th-Sc and Th-Co-Zr/10 discriminant diagrams. Elemental ratios of Th/Sc, La/Sc, Cr/Th with average 0.91, 3.18, 10.13 respectively and La/Th-Hf plot suggest a felsic source rock. The Kopili shale was deposited in freshwater, continental island arc basin with fluctuating redox conditions, receiving sediments from weathered Himalayan granites and gneisses under a warm and humid climate. Subsequently, they underwent diagenetic alteration by low-pH fluid(s).
{"title":"Mineralogical and geochemical studies of shales from Kopili Formation, Dima Hasao district Assam, North East India: Insights into diagenesis, deposition and provenance","authors":"Amit Tiwari , S.L. Memory , Joe Joseph , R.R. Meshram","doi":"10.1016/j.eve.2024.100039","DOIUrl":"10.1016/j.eve.2024.100039","url":null,"abstract":"<div><div>The Eocene Kopili Formation in the Assam foreland basin records sediment sources, tectonic activity and depositional environments following the India-Eurasia collision. Mineralogical and geochemical analysis of these shales exposed near Garampani, Assam, NE India was conducted to study the diagenesis, palaeoweathering, palaeosalinity, redox conditions, tectonic settings and provenance. The Kopili Formation is composed of mainly shale with thin beds of limestone, black shale and sandstone and these units overlie the Upper Sylhet Limestone. The presence of goethite-rich phosphatic nodules, secondary precipitation within the fissile planes of shale and the occurrence of anatase, talc, smectite and chlorite suggest diagenesis. The prevalence of kaolinite and mean Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Al<sub>2</sub>O<sub>3</sub>/MgO and Rb/Sr values of 86.73, 97.26, 16.36 and 1.32, respectively indicates extensive source rock weathering in humid tropical climate. The Index of Compositional Variation (ICV) values ranging between 0.47 and 2.38 also signify high weathering and tectonically active basin. The Sr/Ba ratio 0.34 ± 0.27 (mean±2σ) suggest overall freshwater basin. The Ni/Co (2.84 ± 2.29), V/Cr (1.65 ± 0.45) and Ce/Ce∗ (0.97 ± 0.63) suggest fluctuating redox environment. The samples predominantly cluster in continental island arc domain on the Th-Sc-Zr/10, La-Th-Sc and Th-Co-Zr/10 discriminant diagrams. Elemental ratios of Th/Sc, La/Sc, Cr/Th with average 0.91, 3.18, 10.13 respectively and La/Th-Hf plot suggest a felsic source rock. The Kopili shale was deposited in freshwater, continental island arc basin with fluctuating redox conditions, receiving sediments from weathered Himalayan granites and gneisses under a warm and humid climate. Subsequently, they underwent diagenetic alteration by low-pH fluid(s).</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100039"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Indian western coast is petroliferous and draws attention from academicians and industrial experts. In this work, geomorphic indices have been calculated to decode neotectonics of the Konkan onshore region on India's west coast. Earthquake and Bouguer anomaly data have been used along with the present-day stress data from the World Stress Map project. Gravity modeling was performed in order to gain seismotectonic insights. The b-values were determined using Z-MAP 7.1 (2021). Morphometric analysis at both linear and spatial scales were performed using the digital elevation model from the data derived from the Shuttle Radar Topography Mission, analyzed with ArcGIS 10.3 (2014) software. Maps depicting slopes, aspects, and reliefs were created. NW-SE trending lineaments in the Konkan plain guided the major stream courses. Two of the five watersheds, watersheds 4 and 5, reveal high tectonic activity, are landslide-prone and host hot springs. Interestingly, watersheds 4 and 5 show high b-values (except near the rivers' sources), low Bouguer anomalies, and higher Hypsometric integral values (0.18523 and 0.16698) than the other watersheds. A low b-value in watershed 3 indicates stress accumulation. Over a larger area, the gravity trend varies from ∼ −80 to 30 mGal. The lineaments diagram deduced from the first vertical derivative technique shows that the structural fabrics mostly trend ∼ NW-SE at the west of the Western Ghat Escarpment (WGE) while it is NE-SW at the east. The tilt derivative ratio technique reveals a major NE-SW trend to the west of the WGE and an E-W trend to the east. Structural interpretations based on drill-cores around Koyna combined with geophysical studies for deep crust will be required are required for a better understanding of the blind (active) structures in the region.
{"title":"Morphometry and active tectonics of the Konkan coast, western India","authors":"Shatavisa Chatterjee , Kutubuddin Ansari , Mery Biswas , Soumyajit Mukherjee , B. Kavitha","doi":"10.1016/j.eve.2024.100041","DOIUrl":"10.1016/j.eve.2024.100041","url":null,"abstract":"<div><div>The Indian western coast is petroliferous and draws attention from academicians and industrial experts. In this work, geomorphic indices have been calculated to decode neotectonics of the Konkan onshore region on India's west coast. Earthquake and Bouguer anomaly data have been used along with the present-day stress data from the World Stress Map project. Gravity modeling was performed in order to gain seismotectonic insights. The b-values were determined using Z-MAP 7.1 (2021). Morphometric analysis at both linear and spatial scales were performed using the digital elevation model from the data derived from the Shuttle Radar Topography Mission, analyzed with ArcGIS 10.3 (2014) software. Maps depicting slopes, aspects, and reliefs were created. NW-SE trending lineaments in the Konkan plain guided the major stream courses. Two of the five watersheds, watersheds 4 and 5, reveal high tectonic activity, are landslide-prone and host hot springs. Interestingly, watersheds 4 and 5 show high b-values (except near the rivers' sources), low Bouguer anomalies, and higher Hypsometric integral values (0.18523 and 0.16698) than the other watersheds. A low b-value in watershed 3 indicates stress accumulation. Over a larger area, the gravity trend varies from ∼ −80 to 30 mGal. The lineaments diagram deduced from the first vertical derivative technique shows that the structural fabrics mostly trend ∼ NW-SE at the west of the Western Ghat Escarpment (WGE) while it is NE-SW at the east. The tilt derivative ratio technique reveals a major NE-SW trend to the west of the WGE and an E-W trend to the east. Structural interpretations based on drill-cores around Koyna combined with geophysical studies for deep crust will be required are required for a better understanding of the blind (active) structures in the region.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100041"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100043
Emma U. Hammarlund , Liselotte Jauffred , Nicole R. Posth , Karina K. Sand
Living organisms and their communities are evolving through time as a result of adaptation to stressors like competition or environmental change. While species also today compete for habitable space and adapt to temperature changes, stressors like antibiotic resistance and climate change can be described as grand challenges to our current human communities. However, humans are also the species that uniquely and actively can influence its own fate by leveraging knowledge of challenges ahead. What hinders us from a unified approach through research is that our understanding of grand challenges and how to meet them remains fragmented and curated within distinct disciplines. Developing a collective framework, requires breaking down disciplinary barriers, which comes at a cost to the research productivity of individual researchers. Here, we discuss how collective evolutionary insights are essential to identify, characterize, and tackle three emergent grand challenges and what lies beyond. We also assess solutions to ease the productivity burden to the individual researcher and propose a path forward to transform current siloed knowledge into impactful tools for tackling the oncoming global challenges.
{"title":"Tackling ongoing crises with collective evolutionary knowledge","authors":"Emma U. Hammarlund , Liselotte Jauffred , Nicole R. Posth , Karina K. Sand","doi":"10.1016/j.eve.2024.100043","DOIUrl":"10.1016/j.eve.2024.100043","url":null,"abstract":"<div><div>Living organisms and their communities are evolving through time as a result of adaptation to stressors like competition or environmental change. While species also today compete for habitable space and adapt to temperature changes, stressors like antibiotic resistance and climate change can be described as grand challenges to our current human communities. However, humans are also the species that uniquely and actively can influence its own fate by leveraging knowledge of challenges ahead. What hinders us from a unified approach through research is that our understanding of grand challenges and how to meet them remains fragmented and curated within distinct disciplines. Developing a <em>collective</em> framework, requires breaking down disciplinary barriers, which comes at a cost to the research productivity of individual researchers. Here, we discuss how collective evolutionary insights are essential to identify, characterize, and tackle three emergent grand challenges and what lies beyond. We also assess solutions to ease the productivity burden to the individual researcher and propose a path forward to transform current siloed knowledge into impactful tools for tackling the oncoming global challenges.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100043"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100044
Andrew C. Scott
The Carboniferous is the first geological Period to experience extensive wildfire. A combination of the diversification of land vegetation and its spread into all major terrestrial settings and the rise in atmospheric oxygen paved the way for the development of significant wildfire occurrence that had a significant impact upon the global Earth system. Here the occurrence and study of Carboniferous charcoal deposits is outlined together with an assessment of the evolution of wildfire systems. The influence of fire on plant distribution is assessed. The impact that wildfire had an impact on terrestrial sedimentary systems is described with examples of post-fire erosion and deposition. The wider redistribution of phosphorous in both terrestrial and marine systems is also considered and it is suggested that such events may have played a role in the formation of black shales both in the lacustrine and the marine environment. The role of fire in relation to the evolution of several plant traits is discussed and it is concluded that at least three – the dropping of coniferous lower branches, the shedding of lycopsid leaves from the trunks of arborescent forms and the development of extensive bark and periderm in a range of plants have some merit. Equally the rise of the liana habit, especially in the pteridosperms may also have had an impact in the spread of wildfires in the Pennsylvanian. It is suggested that the role of wildfire (that today is so important and significant) be considered by geologists and palaeonotologists not only concerned with the evolution of the Carboniferous earth system but also in the Earth system from at least the early Silurian and throughout the rest of the Phanerozoic.
{"title":"Fire in the Carboniferous earth system","authors":"Andrew C. Scott","doi":"10.1016/j.eve.2024.100044","DOIUrl":"10.1016/j.eve.2024.100044","url":null,"abstract":"<div><div>The Carboniferous is the first geological Period to experience extensive wildfire. A combination of the diversification of land vegetation and its spread into all major terrestrial settings and the rise in atmospheric oxygen paved the way for the development of significant wildfire occurrence that had a significant impact upon the global Earth system. Here the occurrence and study of Carboniferous charcoal deposits is outlined together with an assessment of the evolution of wildfire systems. The influence of fire on plant distribution is assessed. The impact that wildfire had an impact on terrestrial sedimentary systems is described with examples of post-fire erosion and deposition. The wider redistribution of phosphorous in both terrestrial and marine systems is also considered and it is suggested that such events may have played a role in the formation of black shales both in the lacustrine and the marine environment. The role of fire in relation to the evolution of several plant traits is discussed and it is concluded that at least three – the dropping of coniferous lower branches, the shedding of lycopsid leaves from the trunks of arborescent forms and the development of extensive bark and periderm in a range of plants have some merit. Equally the rise of the liana habit, especially in the pteridosperms may also have had an impact in the spread of wildfires in the Pennsylvanian. It is suggested that the role of wildfire (that today is so important and significant) be considered by geologists and palaeonotologists not only concerned with the evolution of the Carboniferous earth system but also in the Earth system from at least the early Silurian and throughout the rest of the Phanerozoic.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100044"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100038
Waiza Khalid , Syed Kausar Shamim , Ateeque Ahmad
Given the climate change challenges, Uttarakhand has become crucial for examining land dynamics and regional climate interactions. This study employed a Support Vector Machine (SVM) for land use and land cover mapping for 2024, achieving 94% accuracy and a Kappa coefficient of 0.90, indicating robust mapping. Key land indices such as NDVI, NDWI, NDBI, NDSI, and NDBaI were calculated, along with Land Surface Temperature (LST) from Landsat 8 imagery. These indices were selected for their relevance in representing vegetation health (NDVI), measuring water content (NDWI), assessing urban areas (NDBI), identifying snow cover (NDSI), and highlighting the barren land (NDBaI), which all influence LST. Hotspot analysis with Getis-Ord Gi∗ revealed spatial distribution patterns of LST. Regression analysis showed significant relationships: a strong positive correlation between LST and NDBI (R2 = 0.78) and a substantial negative correlation between LST and NDSI (R2 = −0.80). The strong positive correlation highlights how urbanization contributes to rising surface temperatures, while the substantial negative correlation underscores the cooling effect of snow cover, which is particularly relevant as reduced snow cover could lead to higher LST in the context of climate change. These correlations offer deeper insights into how land cover changes can exacerbate or mitigate climate impacts in Uttarakhand. Two regression models were used for statistical modeling and spatial analysis: Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR). In OLS, the results reveal non-stationarity (p = 0.000) with an R2 value of 0.79 while GWR significantly enhanced performance, achieving an R2 value of 0.94. The improved performance of GWR (R2 = 0.94) compared to OLS (R2 = 0.79) can be attributed to GWR’s ability to account for spatial non-stationarity. This method allows for variations in relationships between LST and explanatory variables across different locations, effectively capturing local patterns that OLS may overlook. Spatial autocorrelation analysis, utilizing Moran’s I, exhibited a decrease from 0.606 (OLS) to 0.02 (GWR), This reduction indicates that GWR effectively captures spatial non-stationarity, minimizing residual autocorrelation by modeling local relationships between LST and its predictors that often remain in global models like OLS, thereby demonstrating its advantages in heterogeneous regions. The findings underscore the importance of employing GWR to better elucidate the connection between LST and its predictors, specifically in regions characterized by spatial non-stationarity, thereby offering insights crucial for informed decision-making amidst changing climatic conditions.
{"title":"Exploring urban land surface temperature with geospatial and regression modelling techniques in Uttarakhand using SVM, OLS and GWR models","authors":"Waiza Khalid , Syed Kausar Shamim , Ateeque Ahmad","doi":"10.1016/j.eve.2024.100038","DOIUrl":"10.1016/j.eve.2024.100038","url":null,"abstract":"<div><div>Given the climate change challenges, Uttarakhand has become crucial for examining land dynamics and regional climate interactions. This study employed a Support Vector Machine (SVM) for land use and land cover mapping for 2024, achieving 94% accuracy and a Kappa coefficient of 0.90, indicating robust mapping. Key land indices such as NDVI, NDWI, NDBI, NDSI, and NDBaI were calculated, along with Land Surface Temperature (LST) from Landsat 8 imagery. These indices were selected for their relevance in representing vegetation health (NDVI), measuring water content (NDWI), assessing urban areas (NDBI), identifying snow cover (NDSI), and highlighting the barren land (NDBaI), which all influence LST. Hotspot analysis with Getis-Ord Gi∗ revealed spatial distribution patterns of LST. Regression analysis showed significant relationships: a strong positive correlation between LST and NDBI (R<sup>2</sup> = 0.78) and a substantial negative correlation between LST and NDSI (R<sup>2</sup> = −0.80). The strong positive correlation highlights how urbanization contributes to rising surface temperatures, while the substantial negative correlation underscores the cooling effect of snow cover, which is particularly relevant as reduced snow cover could lead to higher LST in the context of climate change. These correlations offer deeper insights into how land cover changes can exacerbate or mitigate climate impacts in Uttarakhand. Two regression models were used for statistical modeling and spatial analysis: Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR). In OLS, the results reveal non-stationarity (p = 0.000) with an R<sup>2</sup> value of 0.79 while GWR significantly enhanced performance, achieving an R<sup>2</sup> value of 0.94. The improved performance of GWR (R<sup>2</sup> = 0.94) compared to OLS (R<sup>2</sup> = 0.79) can be attributed to GWR’s ability to account for spatial non-stationarity. This method allows for variations in relationships between LST and explanatory variables across different locations, effectively capturing local patterns that OLS may overlook. Spatial autocorrelation analysis, utilizing Moran’s I, exhibited a decrease from 0.606 (OLS) to 0.02 (GWR), This reduction indicates that GWR effectively captures spatial non-stationarity, minimizing residual autocorrelation by modeling local relationships between LST and its predictors that often remain in global models like OLS, thereby demonstrating its advantages in heterogeneous regions. The findings underscore the importance of employing GWR to better elucidate the connection between LST and its predictors, specifically in regions characterized by spatial non-stationarity, thereby offering insights crucial for informed decision-making amidst changing climatic conditions.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100038"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100040
Andrew B. Schwendemann
By the end of the Permian (∼252 Ma), atmospheric CO2 concentration and temperature had risen sharply as the Earth underwent a time of rapid global warming. The distinctive leaf of glossopterid plants, a group of extinct seed ferns, can be found at southern high paleolatitude localities throughout the Permian. During this time in Antarctica, plants existed in warm environments at polar paleolatitudes where they were subjected to light regimes not experienced by plants today (4 months of continuous light and 4 months of continuous dark). An analysis of the leaf mass per area (LMA) of late Permian Glossopteris leaves from Antarctica gives several insights into how these fossil leaves fit into functional groups and habitats compared to extant plants. The predictive intervals (PI) for Glossopteris LMA (PI: 96.6–129.4 g m−2) span the range of LMAs associated with both deciduous and evergreen leaves. When combined with the known effects of high CO2 and continuous light conditions on leaf LMA, the data suggest that the glossopterids living in these polar latitudes had seasonally deciduous leaves and adaptations that allowed them to thrive in a continuous light environment.
{"title":"A leaf economics analysis of high-latitude Glossopteris leaves using a technique to estimate leaf mass per area","authors":"Andrew B. Schwendemann","doi":"10.1016/j.eve.2024.100040","DOIUrl":"10.1016/j.eve.2024.100040","url":null,"abstract":"<div><div>By the end of the Permian (∼252 Ma), atmospheric CO<sub>2</sub> concentration and temperature had risen sharply as the Earth underwent a time of rapid global warming. The distinctive leaf of glossopterid plants, a group of extinct seed ferns, can be found at southern high paleolatitude localities throughout the Permian. During this time in Antarctica, plants existed in warm environments at polar paleolatitudes where they were subjected to light regimes not experienced by plants today (4 months of continuous light and 4 months of continuous dark). An analysis of the leaf mass per area (LMA) of late Permian <em>Glossopteris</em> leaves from Antarctica gives several insights into how these fossil leaves fit into functional groups and habitats compared to extant plants. The predictive intervals (PI) for <em>Glossopteris</em> LMA (PI: 96.6–129.4 g m<sup>−2</sup>) span the range of LMAs associated with both deciduous and evergreen leaves. When combined with the known effects of high CO<sub>2</sub> and continuous light conditions on leaf LMA, the data suggest that the glossopterids living in these polar latitudes had seasonally deciduous leaves and adaptations that allowed them to thrive in a continuous light environment.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100040"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100037
Elizabeth Santos Pereira , Camila Américo dos Santos , Ruan Vargas , Ivandro Patrick de Oliveira Coutinho , Kátia Leite Mansur , Jhone Caetano de Araújo , Marcus Felipe Emerick Cambra , Elisa Elena de Souza Santos , Guilherme Borges Fernandez , Pedro Michelotti , Fábio Ferreira Dias
According to IPCC projections, if there is no joint action between countries to curb the advance of greenhouse gas emissions, the temperature could rise by up to 4 °C, the worst-case scenario. With rising temperatures come adversities that will be and are being faced worldwide, one of which is rising sea levels. Given these level sea-level fluctuations and future projections, there is a need for research into multi-temporal coastline variations, thus providing a view of the past, present, and future of coastal zones around the globe, given that the world's growing population lives on the coast and that a repositioning of the coastline towards the continent has and will have devastating effects on populous regions. This work aims to analyze the coastline variations for the municipality of São Francisco de Itabapoana/Rio de Janeiro (Brazil). Three time periods were chosen: first, for the past 4773–4400 cal yr BP; second, for the present period between 1984 and 2022; third, to project a future scenario for the year 2100 using the sixth IPCC report on mean sea level. For the analysis of the coastline of the present, the area chosen was the entire length of the coast of the municipality of São Francisco de Itabapoana, and for the past and future projections, the area selected was the stretch from Lagoa Doce beach to the mouth of the Itabapoana river. The methodology used consisted of obtaining and processing high-resolution drone images and using Landsat satellite images (5, 7, and 8) to reconstruct and build sea levels for the three time periods chosen in this study. Based on the drone images, a digital surface model and an orthophoto were produced, which were used to reconstruct the sea level of the past when it was 2.5 m higher than the current level and to construct the future scenario (2100) with the scenario of 1.01 m higher than the current level. In the past, the results showed that the study area was flooded and that the current paleocean was active. The worst-case scenario from the IPCC's sixth report (1.01 m) was chosen for the future simulation. The result indicated that the area near the mouth, which is inhabited, will be flooded; in other words, there will be a social, environmental, and economic risk for the region. For the present time frame, the extraction of the coastline from 1984 to 2022 showed the evolution of the entire coastline of the municipality, both positive and negative, showing that the active cliff, which is on Lagoa Doce beach, is eroding continuously. The results show that in the reconstruction of the past, the paleofault was active, indicating that the ridges developed later. The current rate of change of the coastline indicated that it is generally stable in the municipality. The simulation for 2100 shows that the mouth of the Itabapoana River will suffer severe flooding, and that adaptations will be necessary for the region's population.
{"title":"Coastline variations on a section of a coast dominated by cliffs: Past, current and future changes in the municipality of São Francisco de Itabapoana, Brazil","authors":"Elizabeth Santos Pereira , Camila Américo dos Santos , Ruan Vargas , Ivandro Patrick de Oliveira Coutinho , Kátia Leite Mansur , Jhone Caetano de Araújo , Marcus Felipe Emerick Cambra , Elisa Elena de Souza Santos , Guilherme Borges Fernandez , Pedro Michelotti , Fábio Ferreira Dias","doi":"10.1016/j.eve.2024.100037","DOIUrl":"10.1016/j.eve.2024.100037","url":null,"abstract":"<div><div>According to IPCC projections, if there is no joint action between countries to curb the advance of greenhouse gas emissions, the temperature could rise by up to 4 °C, the worst-case scenario. With rising temperatures come adversities that will be and are being faced worldwide, one of which is rising sea levels. Given these level sea-level fluctuations and future projections, there is a need for research into multi-temporal coastline variations, thus providing a view of the past, present, and future of coastal zones around the globe, given that the world's growing population lives on the coast and that a repositioning of the coastline towards the continent has and will have devastating effects on populous regions. This work aims to analyze the coastline variations for the municipality of São Francisco de Itabapoana/Rio de Janeiro (Brazil). Three time periods were chosen: first, for the past 4773–4400 cal yr BP; second, for the present period between 1984 and 2022; third, to project a future scenario for the year 2100 using the sixth IPCC report on mean sea level. For the analysis of the coastline of the present, the area chosen was the entire length of the coast of the municipality of São Francisco de Itabapoana, and for the past and future projections, the area selected was the stretch from Lagoa Doce beach to the mouth of the Itabapoana river. The methodology used consisted of obtaining and processing high-resolution drone images and using Landsat satellite images (5, 7, and 8) to reconstruct and build sea levels for the three time periods chosen in this study. Based on the drone images, a digital surface model and an orthophoto were produced, which were used to reconstruct the sea level of the past when it was 2.5 m higher than the current level and to construct the future scenario (2100) with the scenario of 1.01 m higher than the current level. In the past, the results showed that the study area was flooded and that the current paleocean was active. The worst-case scenario from the IPCC's sixth report (1.01 m) was chosen for the future simulation. The result indicated that the area near the mouth, which is inhabited, will be flooded; in other words, there will be a social, environmental, and economic risk for the region. For the present time frame, the extraction of the coastline from 1984 to 2022 showed the evolution of the entire coastline of the municipality, both positive and negative, showing that the active cliff, which is on Lagoa Doce beach, is eroding continuously. The results show that in the reconstruction of the past, the paleofault was active, indicating that the ridges developed later. The current rate of change of the coastline indicated that it is generally stable in the municipality. The simulation for 2100 shows that the mouth of the Itabapoana River will suffer severe flooding, and that adaptations will be necessary for the region's population.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100037"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100035
Praveen Chandra Singh , Divya Prakash
Phase equilibria modeling becomes a widely accepted tool to constrain the P-T conditions experienced by the metamorphic terrain because of its advantage over the earlier methods e.g., conventional methods and petrogenetic grids. In this study, garnet stability in the mafic granulite has been examined in response to bulk composition and P-T conditions. Karimnagar granulite terrain (KGT) consists of garnet-free mafic granulite along with garnet-bearing metapelite and silica deficient Mg-Al granulite as an enclave within granite gneiss. Mafic granulite consists of amphibole, orthopyroxene, clinopyroxene, and plagioclase with a minor modal amount of biotite and quartz. Mafic granulite has experienced three distinct metamorphic stages: (a) prograde stage defined by inclusions of minerals like amphibole and quartz within the orthopyroxene and augite, (b) peak stage characterized by coarse grain association of amphibole, orthopyroxene, augite, plagioclase, and minor quartz, (c) the retrograde stage illustrated with coronal growth of amphibole over orthopyroxene and augite. The phase equilibria diagrams were calculated in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-O2 (NCKFMASHTO) model system using bulk rock compositions. Our results show that mafic granulite of the study area has achieved the highest P-T condition of 7 kbar and 800 °C and followed a clock-wise metamorphic trajectory. The calculated P-T pseudosection for two samples indicates the stability of garnet varies between 7.5 and 9.5 kbar at 800 °C. The calculated P-Mo pseudosection (at 800 °C) illustrates the lower stability limit of garnet further goes down with the increase in Al2O3 and FeO in the bulk composition.
{"title":"Phase equilibria constraints on the stability of garnet in mafic granulite: An example from Karimnagar granulite terrain, Eastern Dharwar Craton, India","authors":"Praveen Chandra Singh , Divya Prakash","doi":"10.1016/j.eve.2024.100035","DOIUrl":"10.1016/j.eve.2024.100035","url":null,"abstract":"<div><p>Phase equilibria modeling becomes a widely accepted tool to constrain the <em>P-T</em> conditions experienced by the metamorphic terrain because of its advantage over the earlier methods e.g., conventional methods and petrogenetic grids. In this study, garnet stability in the mafic granulite has been examined in response to bulk composition and <em>P-T</em> conditions. Karimnagar granulite terrain (KGT) consists of garnet-free mafic granulite along with garnet-bearing metapelite and silica deficient Mg-Al granulite as an enclave within granite gneiss. Mafic granulite consists of amphibole, orthopyroxene, clinopyroxene, and plagioclase with a minor modal amount of biotite and quartz. Mafic granulite has experienced three distinct metamorphic stages: (a) prograde stage defined by inclusions of minerals like amphibole and quartz within the orthopyroxene and augite, (b) peak stage characterized by coarse grain association of amphibole, orthopyroxene, augite, plagioclase, and minor quartz, (c) the retrograde stage illustrated with coronal growth of amphibole over orthopyroxene and augite. The phase equilibria diagrams were calculated in the Na<sub>2</sub>O-CaO-K<sub>2</sub>O-FeO-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-H<sub>2</sub>O-TiO<sub>2</sub>-O<sub>2</sub> (NCKFMASHTO) model system using bulk rock compositions. Our results show that mafic granulite of the study area has achieved the highest <em>P-T</em> condition of 7 kbar and 800 °C and followed a clock-wise metamorphic trajectory. The calculated <em>P-T</em> pseudosection for two samples indicates the stability of garnet varies between 7.5 and 9.5 kbar at 800 °C. The calculated P-Mo pseudosection (at 800 °C) illustrates the lower stability limit of garnet further goes down with the increase in Al<sub>2</sub>O<sub>3</sub> and FeO in the bulk composition.</p></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100035"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2950117224000050/pdfft?md5=c341b694048740685a04de7baa1e1c4a&pid=1-s2.0-S2950117224000050-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100046
Zandile Mncube , Sifiso Xulu , Nkanyiso Mbatha
Remote sensing of nighttime light (NTL) offers a unique and practical means of assessing human developments through snapshots of nocturnal lighting captured from space. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) is one of the widely used NTL products and is now publicly available on Google Earth Engine (GEE), which allows accelerated analysis using different geospatial approaches. Here, we perform a comparative trajectory analysis of NTL over the three largest cities of South Africa between 2014 and 2023, and project the changes for 2027 based on Markov chain analysis. Our results show that the NTL increased steadily for the city of Durban (from 27.93 nW cm−2.sr−1 in 2014 to 29.45 nW cm−2.sr−1 in 2023) but decreased in the cities of Cape Town (from 32.30 nW cm−2.sr−1 in 2014 to 31.14 nW cm−2.sr−1 in 2023) and Johannesburg (from 52.19 nW cm−2.sr−1 in 2014 to 46.82 nW cm−2.sr−1 in 2023). The unstable power supply of South African cities can affect the NTL data. In addition, from our results, a similar pattern for each of these cities is observed to be in line with load shedding events in the country, especially for Cape Town and Johannesburg. Regarding the spatiotemporal distribution of the NTL, the central areas have medium to high radiance and have been spreading to the periphery of the cities since 2014. Moreover, land use and land cover (LULC) analysis reveals that developed urban areas, shown by dense built-up areas, coincide with the locations of medium and high NTL radiances. The assessment of NTL changes across low, medium, and high classes indicates a stable configuration with no large changes between classes; this is also observed on the spatial projection of NTL for the year 2027. Our results shed light on NTL mapping in large cities, an area that is constantly evolving due to new developments in remote sensing.
{"title":"Analysis of nighttime lights over the cities of Cape Town, Durban and Johannesburg, South Africa","authors":"Zandile Mncube , Sifiso Xulu , Nkanyiso Mbatha","doi":"10.1016/j.eve.2024.100046","DOIUrl":"10.1016/j.eve.2024.100046","url":null,"abstract":"<div><div>Remote sensing of nighttime light (NTL) offers a unique and practical means of assessing human developments through snapshots of nocturnal lighting captured from space. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) is one of the widely used NTL products and is now publicly available on Google Earth Engine (GEE), which allows accelerated analysis using different geospatial approaches. Here, we perform a comparative trajectory analysis of NTL over the three largest cities of South Africa between 2014 and 2023, and project the changes for 2027 based on Markov chain analysis. Our results show that the NTL increased steadily for the city of Durban (from 27.93 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2014 to 29.45 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2023) but decreased in the cities of Cape Town (from 32.30 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2014 to 31.14 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2023) and Johannesburg (from 52.19 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2014 to 46.82 nW cm<sup>−2</sup>.sr<sup>−1</sup> in 2023). The unstable power supply of South African cities can affect the NTL data. In addition, from our results, a similar pattern for each of these cities is observed to be in line with load shedding events in the country, especially for Cape Town and Johannesburg. Regarding the spatiotemporal distribution of the NTL, the central areas have medium to high radiance and have been spreading to the periphery of the cities since 2014. Moreover, land use and land cover (LULC) analysis reveals that developed urban areas, shown by dense built-up areas, coincide with the locations of medium and high NTL radiances. The assessment of NTL changes across low, medium, and high classes indicates a stable configuration with no large changes between classes; this is also observed on the spatial projection of NTL for the year 2027. Our results shed light on NTL mapping in large cities, an area that is constantly evolving due to new developments in remote sensing.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100046"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.eve.2024.100047
S. Karunarathne , P.L. Dharmapriya , W.M.H.M. Wijesinghe , M. Hellers , A.U. Wijenayake , H.M.T.G.A. Pitawala , E.K.C.W. Kularathna
The Mannar Basin is a rift basin formed during the breakup of Gondwana, comprising sedimentary deposits from multiple cycles. Exploration for hydrocarbons has uncovered igneous sequences distributed throughout the basin's sedimentary sequences. These sequences exhibit geochemical characteristics, typical for flood basalts formed during a series of eruptions from 60 to 62 Ma. Previous studies have focused on the petroleum system, tectonostratigraphy, lithostratigraphy, and the paleo-environmental setting, therefore, little was known about the petrogenesis of this flood basalt sequence. This study investigates the petrogenesis of the flood basalt sequence, focusing on crystallization temperature, source magma characteristics, and the nature of magma fractional crystallization. Additionally, it examines the mineralogical characteristics, including clay minerals, of the interstratified sedimentary layers to interpret their origins—an area that has not been previously studied in depth. Petrographic thin sections were prepared from unwashed drill cuttings taken from a depth of 4000–4200 m in the Barracuda petroleum exploration well. A detailed petrographic study was conducted on these samples to investigate the petrogenesis. Additionally, electron probe microanalysis (EPMA) was performed to determine the mineral chemistry of the basalt and interstratified sedimentary rock samples. The basalts are primarily composed of plagioclase (An62-82) and clinopyroxene (mostly augite), with minor occurrences of orthopyroxene (En54-67) and ulvöspinel. Only the lower-most basalt layers (4200–4210 m) contain olivine (Fo56-71). High-Al orthopyroxenes were observed in the shallower sequence. Mineral zoning and mineral chemical variations record fractional crystallization of the mafic magma. Together, these minerals reflect a complex magmatic evolution, where, initially, high-temperature conditions prevailed, followed by differentiation and fractional crystallization; a transition from primitive to more evolved conditions. Geothermometric calculations indicate crystallization temperatures of the basalt varying from 1330 to 1340 °C, typically associated with mantle-derived magmas and representing high-temperature magmatic processes.
The interlayered sedimentary rocks within the basalt sequence are dark-coloured and consist of weathered feldspar and clinopyroxenes, with minor quartz and calcite. Powder x-ray diffraction (XRD) analyses reveal the presence of clay minerals such as smectite, antigorite, attapulgite, and chlorite in these sedimentary rocks. While unpublished reports suggest that the interlayered rocks are sandstones and shales (based on gamma-ray log data), these analyses indicate that they are volcaniclastic sediments resulting from the weathering of individual layers of the flood basalt sequence after their eruption.
{"title":"Petrogenesis of paleocene flood basalt sequence and interlayered sedimentary successions in the Mannar Basin – Offshore Sri Lanka (Northern Equatorial margin of the Indian Ocean)","authors":"S. Karunarathne , P.L. Dharmapriya , W.M.H.M. Wijesinghe , M. Hellers , A.U. Wijenayake , H.M.T.G.A. Pitawala , E.K.C.W. Kularathna","doi":"10.1016/j.eve.2024.100047","DOIUrl":"10.1016/j.eve.2024.100047","url":null,"abstract":"<div><div>The Mannar Basin is a rift basin formed during the breakup of Gondwana, comprising sedimentary deposits from multiple cycles. Exploration for hydrocarbons has uncovered igneous sequences distributed throughout the basin's sedimentary sequences. These sequences exhibit geochemical characteristics, typical for flood basalts formed during a series of eruptions from 60 to 62 Ma. Previous studies have focused on the petroleum system, tectonostratigraphy, lithostratigraphy, and the paleo-environmental setting, therefore, little was known about the petrogenesis of this flood basalt sequence. This study investigates the petrogenesis of the flood basalt sequence, focusing on crystallization temperature, source magma characteristics, and the nature of magma fractional crystallization. Additionally, it examines the mineralogical characteristics, including clay minerals, of the interstratified sedimentary layers to interpret their origins—an area that has not been previously studied in depth. Petrographic thin sections were prepared from unwashed drill cuttings taken from a depth of 4000–4200 m in the Barracuda petroleum exploration well. A detailed petrographic study was conducted on these samples to investigate the petrogenesis. Additionally, electron probe microanalysis (EPMA) was performed to determine the mineral chemistry of the basalt and interstratified sedimentary rock samples. The basalts are primarily composed of plagioclase (An<sub>62-82</sub>) and clinopyroxene (mostly augite), with minor occurrences of orthopyroxene (En<sub>54-67</sub>) and ulvöspinel. Only the lower-most basalt layers (4200–4210 m) contain olivine (Fo<sub>56-71</sub>). High-Al orthopyroxenes were observed in the shallower sequence. Mineral zoning and mineral chemical variations record fractional crystallization of the mafic magma. Together, these minerals reflect a complex magmatic evolution, where, initially, high-temperature conditions prevailed, followed by differentiation and fractional crystallization; a transition from primitive to more evolved conditions. Geothermometric calculations indicate crystallization temperatures of the basalt varying from 1330 to 1340 °C, typically associated with mantle-derived magmas and representing high-temperature magmatic processes.</div><div>The interlayered sedimentary rocks within the basalt sequence are dark-coloured and consist of weathered feldspar and clinopyroxenes, with minor quartz and calcite. Powder x-ray diffraction (XRD) analyses reveal the presence of clay minerals such as smectite, antigorite, attapulgite, and chlorite in these sedimentary rocks. While unpublished reports suggest that the interlayered rocks are sandstones and shales (based on gamma-ray log data), these analyses indicate that they are volcaniclastic sediments resulting from the weathering of individual layers of the flood basalt sequence after their eruption.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100047"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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