Carbonate Bank Research Articles

Compound-clinoform model for tide-influenced deltas in the mixed siliciclastic–carbonate Cisco Group, Upper Pennsylvanian (Virgilian), Eastern Shelf of the Permian Basin, U.S.A.

ABSTRACT Deltas in the Cisco Group contain significant volumes of potential reservoir sandstones in the Upper Pennsylvanian (Virgilian stage) mixed siliciclastic–carbonate succession in the Eastern Shelf of the Permian Basin. While early studies predominantly supported a river-dominated model for these deltas, our findings establish the presence of tide-influenced deltas characterized by the following features: i) predominant heterolithic lithology, ii) diagnostic structures such as flaser bedding, bidirectional ripple cross-lamination, or double-mud drapes, iii) an abundance of interpreted fluid muds, and iv) elongated bars on the subaqueous platform. Through analysis of 290.2 m of core, we identify six facies associations related to tide-influenced deltaic systems in highstand and falling-stage intervals of the proximal Eastern Shelf: delta plain–tidal flat, distributary channel and distributary-mouth bar (delta front) deposits on the subaerial delta; subaqueous delta topset, subaqueous delta foreset, and prodelta deposits on the subaqueous delta. Moreover, two additional facies associations, transgressive shelf deposits and subtidal shallow-water carbonates, record continuous episodic transgressions in the deltaic packages. Well-log cross sections reveal repetitive stacking of deltas, typical of icehouse systems, and sandstone mapping suggests elongated tidal bars forming the interpreted subaqueous delta platforms. These features suggest a compound-clinoform morphology of the Cisco Group deltas akin to modern tide-influenced deltas that have carbonate banks such as the Gulf of Papua. This compound-clinoform morphology has implications for the elongate geometry and isolation of sandstone reservoirs, impacting fluid migration and storage. Moreover, these insights extend beyond the Cisco Group to other Pennsylvanian and Permian levels on the Eastern Shelf, as well as to other deltas in mixed siliciclastic–carbonate systems in icehouse conditions.

The Paleogene Forebulge Carbonate Banks, Zagros Foreland Basin, Northern Iraq: their Paleogeography, Basin Evolution, and Economic Implications

The Paleogene sequence of Zagros foreland basin NE Iraq during the Late Paleocene- Middle Eocene is punctuated by linear and disconnected chains of carbonate bank-ramp associations. These carbonate units had developed over the NW-SE trending Paleogene basin forebuldge. Discussion of origin, facies type, and stratigraphic architecture of these banks and associated facies was fully covered by the first part of this research project. In this part the chronostratigraphic synthases of the sequence, the paleogeography, and basin evolution is examined as an integral part of the investigation of the evolution of the Paleogene Zagros foreland basin. Research methods include regional stratigraphic correlation, and biostratigraphic data compilation to infer the chronostratigraphic sequence of the events. The paleogeographic facies mapping and basin history are reviewed accordingly. Research data are collected from 15 master surface sections. In addition to the re-examination and re-interpretation of 40 previously studied surface and subsurface well logs, which are compiled for basin-wide study and regional paleogeographic mapping. The analysis of the compiled biostratigraphic data shows that the inferred age of the associated stratigraphic units is as follows: Sinjar Formation. (E. Thanetian – L. Ypresian), Khurmala Formation (Ypresian - E. Lutetian), Kolosh Formation (Daian -Thanetian), and Aaliji Formation (Danian - Ypresian). Based on this chronostratigraphic synthesis, the basin forebulge history during the Paleogene period is divided into 5 stages: the Pre-bank, Early Bank Development, Bank-ramp Development, Back-bank Lagoon, and Lagoonal dolomitization stage. The paleogeography and paleofacies maps of each stage is discussed in terms of the basin forebulge evolution. An alternative hydrocarbon play of the forebulge-controlled Paleogene sequence is discussed, with a case study from the Sufaiyah oil field of northwest Iraq.

The Paleogene Carbonate Banks of the Zagros Foreland Basin’s Forebulge, Northern Iraq: Stratigraphic Architectures and Facies Associations

The Paleogene sequence of the Zagros foreland basin of NE Arabiais punctuated by a linear chain of carbonate bank-ramp associations. These carbonate banks had developed over the NW-SE trending basin forebulge. Continued convergence and compressional tectonics of the basin made the forebulge become incipient and shallow enough to commence carbonate sedimentation. The porpose of this work is to investigate the origin, facies and regional stratigraphic relations of these carbonates to the forebulge and other basin depozones. Stratigraphic data of this research are collected from (15), measured outcrop sections distributed over the basin forebulge zone and surroundings. In addition, re-examination and reinterpretation of (30) previously studied surface and subsurface sections are compiled into the study. This done to integrate the regional facies distribution and basin-wide sequence stratigraphic architecture. Stratigraphic investigations include lithostratigraphic logging and correlation, microfacies analysis, and facies modeling. Four major banks were recognized, three of these banks (informally named: Dohuk, Kirkuk, and Sulaimaniyah) were developed over the forebulge zone. The other one (Sinjar bank) of the Sinjar area, is related to basininversion mechanism. The forebulge carbonate banks were developed as the reefal limestone of the Sinjar Formation, and the lagoonal carbonate and shale of the Khurmala Formation. The Sinjar Formation is dominated by coralgal reef and foraminiferal-shoals with facies spectrum forming the basic body of the bank. The ramp setting was developed on both sides of the bank. The bank limestone represents the inner ramp facies, whilea windward ramp is developed as foraminiferal bioclastic limestone fingers into the back-bulge basinal marlstone of the Aaliji Formation. A leeward ramp facies was developed into the foredeep depozone, with bioclastic carbonate intercalations that characterize the upper part of the Kolosh Formation. At a later stage of basin shoaling (Early Eocene), a carbonate back-bank lagoon was developed over the foredeep area. It became gradually, isolated at certain parts of the basin, and finally replaced by the dolostone of the Khurmala Formation.

Dismantling of an isolated tropical carbonate platform through flank collapse and canyon erosion, Coral Sea, Northeast Australia

The steep slopes of carbonate platforms frequently display large-scale sediment destabilization features like rockfalls, mass transport complexes, and slope erosion. The processes and factors triggering such instabilities and how they interact are a matter of ongoing discussion. We use hydroacoustic, sedimentological, and seafloor imaging data to map and characterize slope instabilities and potential controlling factors at the flank of the isolated Tregrosse carbonate bank in the Coral Sea, northeast Australia. Erosion of gullies and submarine valleys is concentrated in slope segments with the platform rim at several 10s of meters of water depth, i.e. where there is potential for sediment transfer from the bank interior to the slope. Gravity core data indicate that most sediment export from the platform occurs during sea-level fall. The toe of slopes neighboring segments with a shallower platform rim are mostly characterized by mass-transport complexes of platform rim and upper slope rocks forming extended block fields. Distal slope areas are dismantled through submarine landslides resulting in scalloped head scarps. The basal detachment surface of these submarine landslides appears to be rooted in several 100 s of meters in the subsurface at a lithological heterogeneity, which is documented by a gamma-ray peak in the downhole logging data from Ocean Drilling Program Site 817. Our findings show that (1) canyon erosion, (2) platform rim and upper slope destabilization as well as (3) lower slope dismantling, largely act independently of each other to destabilize the flanks of the carbonate bank. The complexity of the carbonate platform dismantling processes and the corresponding controlling factors shown in this study should also be considered when interpreting seismic morphological data.

COMPOUND CLINOFORM MODEL FOR TIDAL-INFLUENCED DELTAS IN THE MIXED SILICICLASTIC-CARBONATE CISCO GROUP, VIRGILIAN (GZHELIAN), EASTERN SHELF OF THE PERMIAN BASIN, U.S.A.

Deltas in the Cisco Group contain significant volumes of potential reservoir sandstones in the Late Pennsylvanian (Virgilian/Gzhelian) mixed siliciclastic-carbonate succession in the Eastern Shelf of the Permian Basin. While early studies predominantly supported a river-dominated model for these deltas, our findings establish the presence of tide-influenced deltas characterized by the following features: (i) predominant heterolithic lithology; (ii) diagnostic structures such as flaser bedding, bidirectional ripple cross-lamination, or double-mud drapes; (iii) an abundance of interpreted fluid muds; and (iv) elongated bars on the subaqueous platform. Through analysis of 290.2 m of core, we identify six (6) facies associations related to tide-influenced deltaic systems in highstand and falling-stage intervals of the proximal Eastern Shelf: lower-delta-plain/embayed tidal flat, distributary channel and distributary mouth bar/delta front deposits on the subaerial delta; subaqueous delta platform, subaqueou s delta foreset, and prodelta deposits on the subaqueous delta. Moreover, two (2) additional facies associations, transgressive shelf deposits, and subtidal shallow-water carbonates, record continuous episodic transgressions within the deltaic packages. Well-log cross sections reveal repetitive stacking of deltas, typical of icehouse systems, and sandstone mapping suggests elongated tidal bars forming the interpreted subaqueous delta platforms. These features suggest a compound clinoform morphology of the Cisco Group deltas akin to modern tide-influenced deltas that have carbonate banks such as the Gulf of Papua. This compound clinoform morphology has implications for the elongate geometry and isolation of sandstone reservoirs, impacting fluid migration and storage. Moreover, these insights extend beyond the Cisco Group to other Pennsylvanian and Permian levels on the Eastern Shelf, as well as to other deltas in mixed siliciclastic-carbonate systems in icehouse conditions.

Vegetation restoration improved aggregation stability and aggregated-associated carbon preservation in the karst areas of Guizhou Province, southwest China.

The change in the soil carbon bank is closely related to the carbon dioxide in the atmosphere, and the vegetation litter input can change the soil organic carbon content. However, due to various factors, such as soil type, climate, and plant species, the effects of vegetation restoration on the soil vary. Currently, research on aggregate-associated carbon has focused on single vegetation and soil surface layers, and the changes in soil aggregate stability and carbon sequestration under different vegetation restoration modes and in deeper soil layers remain unclear. Therefore, this study aimed to explore the differences and relationships between stability and the carbon preservation capacity (CPC) under different vegetation restoration modes and to clarify the main influencing factors of aggregate carbon preservation. Grassland (GL), shrubland (SL), woodland (WL), and garden plots (GP) were sampled, and they were compared with farmland (FL) as the control. Soil samples of 0-40 cm were collected. The soil aggregate distribution, aggregate-associated organic carbon concentration, CPC, and stability indicators, including the mean weight diameter (MWD), fractal dimension (D), soil erodibility (K), and geometric mean diameter (GMD), were measured. The results showed that at 0-40 cm, vegetation restoration significantly increased the >2 mm aggregate proportions, aggregate stability, soil organic carbon (SOC) content, CPC, and soil erosion resistance. The >2 mm fractions of the GL and SL were at a significantly greater proportion at 0-40 cm than that of the other vegetation types but the CPC was only significantly different between 0 and 10 cm when compared with the other vegetation types (P<0.05). The >2 mm aggregates showed a significant positive correlation with the CPC, MWD, and GMD (P<0.01), and there was a significant negative correlation with the D and K (P<0.05). The SOC and CPC of all the vegetation types were mainly distributed in the 0.25-2 mm and <0.25 mm aggregate fractions. The MWD, GMD, SOC, and CPC all gradually decreased with increasing soil depth. Overall, the effects of vegetation recovery on soil carbon sequestration and soil stability were related to vegetation type, aggregate particle size, and soil depth, and the GL and SL restoration patterns may be more suitable in this study area. Therefore, to improve the soil quality and the sequestration of organic carbon and reduce soil erosion, the protection of vegetation should be strengthened and the policy of returning farmland to forest should be prioritized.

Изотопный состав и условия образования фаменских карбонатолитов Центрально-Хорейверского вала (Хорейверская впадина, Печорская плита)

The article presents results of the distribution of the isotopic composition of 13C and 18O (119 samples) across four facies zones to substantiate the conditions of Famennian carbonation accumulation. The Lower Famennian carbonates of the shoal zone showed values of 13C (1.5 ± 0.15 %), 18O (25.01 ± 0.29 %) reflecting evaporative processes in a shallow basin in a warm and dry climate. For the rocks of the microbial mounds zone, the values of 13C (2.47 ± 1.12 %) and 18O (23.51 ± 1.12 %) reflect an increase in bioproductivity and some fluctuation in water salinity. In the limestones of the zone of transition to depression, the variations of isotopic composition are more distinct in the section. Thus, the Early Famennian is characterized by the average values of 13C (0.94 ± 0.59 %) and 18O (23.73 ± 2.18 %) for marine carbonates. The transition to the Middle Famennian is accompanied by isotopic weighting of 13C (1.30 ± 0.47%) and 18O (24.52 ± 1.45%), which shows an increase in evaporation processes under aridization conditions. In the Late Famennian, the isotopic composition abruptly lightens by 13C (–1.05 ± 0.66 %), which is associated with desalination under conditions of climate humidification. At the same time, the value of 18O (25.75 ± 0.31 %) corresponds to the average values for carbonates of the Devonian. The values of 13C (1.04 ± 0.89 %) and 18O (26.01 ± 0.99 %) in the carbonates of the zone slope of the carbonate bank towards the shallow shelf reflect the conditions of the normal sea basin with a slight increase in the evaporation regime during climate aridization. The obtained results indicate that the Famennian sedimentation basin characterized by fluctuations in sea level, facies, water hydrochemistry and climate.

Thermal influence of sills on the chemostratigraphy and mineralogy of carbonate rocks from the Irati formation, Paraná basin

Carbonate rocks and shales are prominent lithologies in atypical petroleum systems. In these settings, the thermal effects of sills play a crucial role leading to mineralogical and geochemical alteration in the host rocks and in the maturation process of the associated organic matter. While extensive research has been conducted on shales within atypical systems, the understanding of the petrophysical and geochemical properties of carbonate rocks remains uncertain in numerous basins. In this study, we selected the Irati Formation (Paraná Basin) to investigate the thermal effects caused by diabase sills on the chemostratigraphic and lithologic features of carbonate rocks. We conducted mineralogical analyses, examined oxygen and carbon stable isotopes, and analyzed inorganic geochemical data from two distinct sections of the formation: one with diabase sills intruding the sequence and the other without identified intrusions in the area. Widespread recrystallization of minerals is observed throughout the studied rock wall, resulting in the formation of marbles and calc-silicate rocks, where dolomite is mainly replaced by calcite. The carbonate bank, located 5–7 m below the sill, is marked by brucite and chrysotile, while the rocks up to 1 m below and above the intrusion show the presence of tremolite, diopside, and antigorite. Substantial variations in elemental data are observed, including a significant increase in SiO2 and K2O below the sill, as well as elevated MgO levels within the carbonate bank. Additionally, stable isotopic signatures of oxygen and carbon display a negative shift influenced by decarbonation and intense fluid flow controlling the reactions. The contact aureole resulting from the intrusion is identified at least 7 m above and below the sill based on mineralogical and inorganic geochemical data.

The case for a World Carbon Bank

This paper explores the idea of creating a new multilateral financial institution, a World Carbon Bank, to channel aid funds and technical expertise to low and middle-income countries, to aid with the green transition. A focused high-return first project could involve phasing out coal power plants and replacing with green alternatives. Coal accounts for 30% of global emissions. Many coal plants are located outside advanced economies and are relatively new. The costs of swapping them out is significant, and most poorer countries have little incentive or capacity to do so. WCB funds would be outright grants and not loans.

Preliminary observations on the coral reef communities in Angria Bank, an isolated carbonate bank in the Northern Indian Ocean

Submerged carbonate banks are of significant geological and biological importance and relatively little is known about the biodiversity of these deeper and less accessible habitats. This study provides pilot information on the biodiversity and spatial distribution of the coral reef communities in Angria Bank, a submerged carbonate platform along the central west coast of India. An exploratory survey was carried out in January 2014 to document the habitat characteristics and biodiversity of different reef communities across a gradient from the western to the eastern edge of the Angria Bank. The western zone of the bank comprises rocky and coralline substrates in contrast to the eastern zone which is sandy with calcareous deposits. The overall biodiversity includes 16 genera of corals from 10 families and 82 species of reef fish from 26 families, comparatively lower than the other major reef formations in the Indian Ocean. The study sites between the depths of 25–29 m along the eastern edge of the bank host abundant and diverse coral communities. The macroalgae was equally abundant in three of the five dive sites along the east zone reflecting the homogeneous distribution of reef communities in the Angria bank. Other invertebrates including members of the phylum Porifera, Mollusca, Annelida, Arthropoda, Echinodermata, and Cnidaria account for 28 species. Angria Bank signifies a biodiversity hotspot and these remote habitats hold the potential to serve as a refugium for the shallow reef communities for a range of environmental disturbances. Further research to understand the effect of climate-associated stress on the reef communities of Angria bank is vital to evolve a conservation strategy to sustain the biodiversity and resilience of these communities.

Ordovician of the conterminous United States

AbstractThe Ordovician rocks of the conterminous United States (US) have a complex history, spanning multiple ancient basins, shifting palaeoclimate and evolving tectonic regimes. The US portion of the palaeocontinent of Laurentia occupied a relatively stable and isolated position around the southern tropics during the Ordovician. In general, Lower Ordovician rocks form a vast autochthonous blanket of fine-grained (tropical) carbonates that covered much of Laurentia, named the ‘Great American Carbonate Bank’. Outboard, ribbon carbonates and graptolitic shales are found in allochthonous fragments of the ancient continental margin. Middle Ordovician strata are more lithologically diverse, including the addition of several regionally distributed sandstones of the inner detrital belt, mostly overlying the Sauk–Tippecanoe unconformity. Upper Ordovician strata show the greatest lithologic and faunal diversity, reflecting steepening topography resulting from regional compression along the south Laurentian (Appalachian) margin. Recent advances in the interpretation of the US Ordovician come primarily from studies of carbon and oxygen stable isotopes, sequence stratigraphy, palaeoecology, tephrochronology, redox geochemistry, strontium isotopes and geochronology.

Carbon accounting, management quality, and bank performance in East Africa

Does it pay to report green activities? This question has dominated academic discussion and has further spiraled into the industry. Questions exist about the value relevance of carbon accounting, given that such practice is voluntary and consumes resources. The question becomes more legitimate when banks whose activities do not negatively affect the environment adopt carbon accounting. Given this perplexing phenomenon, the study examined the impact of carbon accounting on the performance of banks in East Africa. Moreover, the effect of management quality on such a relationship was analyzed. The study relied on eight years of integrated, sustainability, and annual reports of 79 banks in East Africa, collecting the carbon accounting data. A multiple regression estimation technique was employed to estimate the models. The study demonstrated that carbon reporting had a negative and insignificant relationship with the financial performance of banks. In addition, the study showed that management quality turned the relationship between carbon disclosure and firm performance positive, suggesting that the banks with high quality of management benefited financially from carbon reporting. The study concludes that carbon accounting does not benefit East African banks. However, banks that had high quality of management financially benefited from carbon accounting. The significant implication of these results is that banks can benefit from adopting carbon accounting but only when they have high management quality. This study contributes to the debate on the conflicting empirical findings on the value relevance of carbon accounting in Africa, which is scarce.

Late Cambrian climate change recorded by a shift from an arid carbonate platform to a storm‐dominated cool‐water platform at the Gondwana margin (Alborz Zone, Iran)

The Deh‐Molla Formation of the Alborz Zone in northern Iran is a key unit to understanding global sea‐level fluctuations, and likely climate changes during the Furongian Epoch. The sedimentological characteristics of the formation indicate that the succession was deposited on a gently sloping epeiric platform on the northern margin of Gondwana. The Paibian Member 1 of the Deh‐Molla Formation was deposited on a carbonate platform with stable environmental conditions, probably during a (semi)arid climate condition, as indicated by microbial–sponge patch reefs, thick‐bedded units formed in broad facies belts, and a thick dolomite unit formed under evaporative conditions. The overlying Member 2, considered to span the Jiangshanian–Age 10, includes thin‐bedded wavy, and rippled strata known as ribbon rocks. This sequence records considerable environmental fluctuations. Thin‐bedded strata with flat‐pebble conglomerates, hummocky cross‐stratification, lenticular, flaser, and wavy bedding, ripple cross‐lamination, and graded bedding signify that deposition of Member 2 took place in a depositional environment repeatedly affected by tidal currents, and storm waves. A comparison of the Deh‐Molla Formation, and particularly its ribbon rocks with coeval strata in Laurentia and North China reveals secular controls on their development. In contrast to the Furongian strata of the Great American Carbonate Bank, deposited under tropical conditions, the ribbon rocks of the Deh‐Molla Formation suggest deposition in a temperate latitude zone with dominant cool‐water conditions. However, the Deh‐Molla platform was seasonally subjected to monsoons that brought warm tropical waters to the region, and led to rapidly changing environments. Ooids, peloids, stromatolites, and other criteria suggestive of a tropical climate are frequent in Laurentian successions, but absent in the Deh‐Molla Member 2. However, both Laurentian and Gondwanan examples share characters that indicate comparable controls on their development. Significant environmental changes during the Furongian are indicated by the SPICE and HERB events, and the latter is taken as showing biotic and physico‐chemical changes in the ocean and atmosphere, possibly concurrent with the formation of ribbon rocks on different continental blocks.

Devonian to Carboniferous continental-scale carbonate turnover in Western Laurentia (North America): upwelling or climate cooling?

The Devonian to Carboniferous (DC) transition coincided with a green-to-ice house climatic shift, anoxia, disappearance of lower latitude carbonate banks, and turnover from warm-to-cool water carbonate factories. In western Laurentia, the switch to carbonate factories dominated by cool-water biota was contemporaneous with a tectonically driven palaeogeographic change. To investigate this depositional shift and infer the relative impact of climate vs tectonics, a continental-scale sedimentological and geochemical study was conducted on twelve stratigraphic sections of DC strata from western Canada to southern Nevada (USA). The spatial–temporal distribution of microfacies records the turnover from [i] a Famennian lime mud-rich, shallow warm-water carbonate ramp with low sedimentation rates, mesotrophic conditions and tabular geometry to [ii] Tournaisian to Viséan lime mud-depleted and grainstone dominated cool-water carbonate ramp with anomalous high sedimentation rates, oligotrophic conditions and a pronounced slope. Positive excursions of δ18Ocarb (+ 2‰ V-PDB) and δ13Ccarb (+ 4‰ V-PDB) of Lower Mississippian carbonates likely correspond to the first cooling peak of the Carboniferous-Permian icehouse climate, following carbon withdrawal during black shale deposition during the late Famennian and early Tournaisian. However, late Tournaisian return of photozoan elements and their persistence throughout the Viséan suggests that warmer surface water existed, revealing a decoupling of the lower latitude ocean and the atmosphere. Shoaling of the thermocline was likely a result of cold-water upwelling along an open coast, as the Antler orogen no longer provided an oceanic obstruction to the west. This study shows that carbonate platforms are more susceptible to regional changes than global shifts.

Research on the central bank's carbon emission reduction support tool under the dual carbon target

Under the background that central banks have successively issued green financial policies to deal with climate change, on November 8, 2021, the people's Bank of China officially announced the creation and launch of carbon emission reduction support tools to help achieve the "double carbon goal" as soon as possible. Support the development of key areas such as clean energy, energy conservation and environmental protection and carbon emission reduction technologies in a steady, orderly, accurate and direct manner, and leverage more social funds to promote carbon emission reduction. This structural monetary policy tool is different from the traditional monetary policy. It will drive the accurate delivery of basic currency through its special transmission mechanism; Stimulate the overall growth of green credit scale; Promote the adjustment of industrial structure; Help to further improve the relevant information disclosure and review mechanism. At the same time, as a long-term financial instrument, carbon emission reduction support tool still has great room for improvement in the future. It is expected to be continuously improved in supporting credit policies, issuing objects, supporting industries, disclosure mechanism and other aspects.

The microfacies distribution pattern of Cozumel Island in southeastern Mexico: An atoll-like model led by quaternary glacioeustatic sea-level changes

Isolated carbonate banks in stable tectonic settings are ideal for understanding the architecture of sedimentary systems and their response to flooding events. Within these environments, sea-level changes play a primary role in depositing sedimentary units during high sea levels and unconformities during sea-level drops. Microfacies analysis and geologic interpretation, combined with a High Resolution Digital Elevation Model from LiDAR data were used to reevaluate the sediment distribution pattern of Cozumel Island, proposing a new depositional model. The chronostratigraphic framework was established by correlating the exposure surfaces (caliches) of Cozumel with others in adjacent regions. The study of several sections around the island led to the identification of two lithostratigraphic units. Unit 1 comprises two coral reef facies associations (FAs 0 and 1), separated by the Caliche-0 layer. The upper limit of Unit 1 is represented by the Caliche 1 layer and the karst features developed during Marine Isotopic Stage (MIS) 6. Unit 2 was deposited over the ancient karst topography as the lower limit, with Caliche 2 as the upper limit. Unit 2 comprises three facies associations (FAs-2A, B, C), consistent with the protected, open lagoon and the facies of the platform margin, establishing atoll-like depositional conditions. Unit 2 developed during the last interglacial MIS 5e, whereas the Caliche 2 layer started to develop in a post-MIS 5e event during the sea-level drop. This exposed the previous depositional environments to meteoric diagenesis with the formation of the caliche layer. The Caliche 2 layer stabilized the landscape until the present day. Unit 2 correlates to certain morphostratigraphic and geomorphological structures (Terraces I, II, III) on the island. The emplacement of sand islands (FAs-2A), preexisting topography, relative sea-level variations, and sediment supply lead to the pattern and configuration of the depositional model. In addition, the evolution of Cozumel Island during the MIS 5e is similar to other Holocene atoll-like islands in the Caribbean region.

Glacial erosion on a snowball Earth: testing for bias in flux balance, geographic setting, and tectonic regime

On the southwest cape of the Congo craton, a subtropical carbonate bank the size of Greenland was heavily glaciated during two Cryogenian panglacial episodes spaced 10–20 Myr apart. In NW Namibia, the bank underwent crustal stretching with resultant Aegean Sea-type topography during the older and longer Sturtian glaciation (717–661 Ma). This is indicated by angular discordance between glacial and preglacial strata and diamictites sourced from all older units, including crystalline basement. In contrast, the bank was flat-topped and underwent broad thermal subsidence during Marinoan glaciation (646 ± 5–635 Ma), attested by stratal parallellism and diamictites sourced from ≤100 m stratigraphic depth. However, ≥2.0 km of relief existed on the Marinoan continental slope, where most glacial erosion and accumulation occurred. The average rates of Marinoan erosion (2.55–6.80 m/Myr, n = 190) and accumulation (2.65–7.07 m/Myr, n = 211) are indistinguishable, implying that the location in a continental promontory did not bias erosion over accumulation. The average accumulation rates for the Sturtian and Marinoan, scaled for different averaging times, including Marinoan uncertainty, are 3.95–4.93 m/Myr ( n = 183) and 2.65–7.07 m/Myr ( n = 190), respectively, suggesting that a Marinoan glacioeustatic coastal escarpment substituted for rift-related Sturtian basin-and-range topography. These slow rates, comparable to long-term pre-Quaternary accumulation rates on existing abyssal plains, reconcile glacial sedimentology with the feeble hydrologic cycle of snowball Earth.

The impact of banks' financial performance on environmental performance in Africa.

To better understand Africa's banks and the environment, this study investigates the impact of financial performance on environmental performance in Africa. We examined financial performance, environmental performance, and some control indicators dated from 2000 to 2016 by applying panel quantile regression and panel vector autoregressive techniques. Our results indicate that (i) in North African countries, carbon emission had a significant negative impact on financial performance on the 25th quantile and (ii) in the South, carbon emission had a statistically positive impact on financial performance on the 25th and 50th quantiles with the marginal effect increases from the lower quantile to the highest quantile. Also, bank deposits statistically negatively impacted financial performance on the 25th and 50th quantiles for both North and South economies. The dynamic panel quantile results show dissimilar effects at different quantiles. Also, the panel vector autoregressive results show that in North Africa carbon emission had a positive impact. Our results validate the stability test of the panel vector autoregressive model. The granger causality results in the North show a bilateral causal link between carbon emission and bank credit, carbon emission, and bank deposit. Since sustainability has become one of our era's most thorny issues, this paper provides extensive policy directives to assist African nations in boosting a greener future.

Integrated biochemostratigraphy of the Permian-Triassic boundary beds in a shallow carbonate platform setting (Yangou, South China)

Investigation of the end-Permian mass extinction (EPME) has been greatly facilitated by high-resolution conodont biostratigraphic studies. To date, however, a detailed biostratigraphic framework has been lacking for shallow-marine successions of the Tethys region. In the present study, we analyzed carbonate microfacies, conodont biostratigraphy, and carbonate carbon isotopes of the Yangou Quarry section, a shallow-marine EPME succession that accumulated on an isolated carbonate bank on the northern margin of the Yangtze Platform. Microfacies analysis yielded four facies and 8 microfacies that record a seawater deepening immediately following the EPME. Ooids were abundantly produced during the EPME and earliest Triassic mass extinction (ETME) but were replaced by microbial mats, algae, bivalves, and brachiopods during an earliest Triassic transgression. A total of three conodont zones are recognized from the uppermost Changhsingian to the lowermost Griesbachian, in ascending order, the Hindeodus praeparvus Zone, H. parvus Zone, and Isarcicella staeschei Zone. The EPME and PTB (Permian-Triassic boundary) horizons are marked by the first occurrences of H. praeparvus at 6.18 m and H. parvus at 6.57 m, respectively, above the base of the section. The conodont biostratigraphic framework of the Yangou Quarry section was refined through intercalibration with its δ13Ccarb profile. This section records two discrete negative carbon isotope excursions (CIEs) that are correlative with the EPME and ETME horizons, and that can be correlated with similar CIEs at Meishan D and other PTB sections globally. Our study provides the first integrated, high-resolution biochemostratigraphic framework for a shallow-marine PTB succession in the eastern Tethys region, which will facilitate paleoenvironmental studies of similar facies elsewhere as well as correlations with deeper-water facies.

Carbon neutrality, bank lending, and credit risk: Evidence from the Eurozone

The development of a green financial intermediation channel is imperative to achieve zero-carbon economies. In this study, we assess the impact of carbon-neutral lending on the credit risk in the Eurozone. We employ quarterly data for a sample of 344 lending institutions of 19 member states spanning over ten years from 2011 to 2020. Using two specific credit risk measures, the findings show that the exposure to carbon-neutral lending is negatively related to the default risk. The results remain consistent for the various size sorts, depicting that regardless of the bank size, the impact of green financing on the credit risk is the same. We attribute the credit risk reduction to the lower volatility of the borrowers' earnings and cash flows emanating from their sustainable business model. As a consequence of lower credit risk, financial institutions can benefit from lower loan loss provisions and economic capital requirements. This incentive is vital to increase the carbon neutral credit and contribute towards pro-environmental goals.