Initial Transgression Research Articles

Quaternary transgression process controlled by tectonic subsidence over the last 1.35 Ma: New insights from the eastern Bohai Sea

The Quaternary sedimentary history of the Yellow Sea and Bohai Sea offers significant insights into global sea-level changes. This history is intricately linked to tectonic subsidence. However, the process of the Quaternary transgressions of these areas remains controversial due to the lack of cores with comprehensive sedimentary sequences and reliable chronological frameworks in representative sites. This study evaluated the grain size, benthic foraminifera assemblages, quartz optically stimulated luminescence (OSL) dates, and magnetostratigraphy of Core CSH05 (102.4 m) from the eastern boundary of the Bohai Sea. By comparing these results with previous research, new insights were gained into sea-level changes and tectonic events in the Bohai Sea. The paleomagnetic analysis revealed the existence of Brunhes and Matuyama chrons in the core, including the Jaramillo and Cobb Mountain subchrons and Blake excursion. The boundary between the Brunhes and Matuyama chrons was determined at 57.2 m in the core, aligning with adjacent cores. The basal age of the core is estimated to be ~1.35 Ma. Thirteen sedimentary units (U1-U13), consisting of seven neritic deposits and six terrestrial/littoral deposit layers, were identified in the core through sedimentology and environmental proxies (grain size and benthic foraminifera), indicating alternating transgression-regression cycles. OSL samples suggest that the neritic deposits layer (16.2–20.6 m) probably originated during the early Marine Isotope Stage 3 (MIS3), exhibiting a weaker transgression than MIS5 and MIS1. The initial transgression (U13) dates back to no later than 1.35 Ma, representing the earliest documentation in the Bohai Sea. U11 shows a transgression to 1 Ma, aligning with results from adjacent cores, indicating that the Miaodao Island uplift experienced further subsidence between 1 and 0.83 Ma, allowing seawater to inundate the central basin of the Bohai Sea during high sea level periods. The current sea-land configuration structure emerged after 0.3 Ma due to the complete subsidence of the Miaodao Islands Uplift. The Quaternary transgressions in the Bohai Sea demonstrate a coupling relationship with the uplift of the Qinghai Tibet Plateau, glacial-interglacial cycles, and integration of the Yellow River. This study traces the initial transgression in the Bohai Sea to 1.35 Ma and provides a new detailed evolutionary model of the timing and routes for the Quaternary transgression of the Bohai Sea and Yellow Sea, thereby enhancing our understanding of sedimentary evolution and paleoenvironmental changes in the region.

The Paradoxes of Sin: Vengeance as Death Drive in Janet Lewis’s The Wife of Martin Guerre

Abstract If revenge functions to compensate for inequity arising from an initial transgression, thereby restoring equity, can we speak of restoration of an equitable social or personal situation in Janet Lewis’s novel The Wife of Martin Guerre (1941)? This work belongs to Janet Lewis’s series of three novels based on “Cases of Circumstantial Evidence”, of which The Wife of Martin Guerre is the most famous. It concerns the case of Martin Guerre, the sixteenth-century French peasant who apparently returned home to his wife after a long absence but was later revealed to be an impostor. The wife at first believes that the impostor is indeed her husband, then starts to have doubts, gathers information to contest his assertions, develops an exaggerated religious sense of guilt for the sin of adultery, and successfully sues him, leading to his being hanged. Several questions arise: is she justified in feeling guilty for having given in to sexual attraction, thus blinding herself to the available clues pointing to the impostor’s deception? Can the outcome be considered an equitable result, despite the fact that the false Martin Guerre was actually a good administrator, dealing fairly both with his subjects and his wife, and thus created a much more harmonious life for everybody than the lawful husband had done? I consider the story as a case of revenge stemming from an incorrect religious perspective, or alternatively narcissistic damage, which does not bring about redress of a tort, but rather social unhappiness.

Phosphorus cycling during the Hirnantian glaciation

Unlike other mass extinctions of the Phanerozoic, the Late Ordovician mass extinction took place during an icehouse interval, accompanied by the glaciation of Gondwana. Ice sheets reached their maximum during the Hirnantian and global sea-level dropped substantially. Consequently, the shallow tropical shelf environments of Laurentia and Baltica became subaerially exposed or remaining submerged shelves were characterized by very shallow water-depths. Redox proxies suggest that most shallow shelf settings were well oxygenated to that time, while the global extent of anoxic environments increased, implying that deoxygenation was confined to the open ocean. We speculate that the burial rate of the nutrient phosphorus (P) on shelves was minimal during the Hirnantian glacial maximum (HGM) due to bypass of the shelves in respect to the incoming riverine dissolved load. Hence, a large excess of bioavailable P entering the open ocean would have stimulated phytoplankton production which lowered oxygen concentrations by aerobic respiration.In order to test this hypothesis, we determined reactive P (Preact) contents in two low-latitude carbonate successions (Anticosti Island and Estonia) spanning the HGM. Moreover, we measured total organic carbon (C) concentrations and calculated C/P ratios to evaluate the burial efficiency of P. Samples from both sites are characterized by overall low Preact contents. We observe a decreasing trend in Preact towards the HGM, reaching a minimum during the initial transgression thereafter. C/P ratios suggest efficient P-burial throughout the study interval and, hence, Preact contents are assumed to be a direct measure of primary productivity, P-availability, and P-burial. Using the Preact concentrations, we modeled shelf P-burial fluxes with estimates for global shelf area and sedimentation rates. The model suggests that shelf P-burial fluxes around the HGM were approximately halved due to a reduced shelf area and minimum Preact contents. With the assumption of a constant P-input to the ocean, the proposed scenario serves as a plausible explanation for the observed redox gradients.

Integrated statistical analysis of calcareous nannofossil and elemental geochemistry of an outcrop from of the eastern Cenomanian Western Interior Seaway: Novel insights of shallow marine paleoceanography and nannoplankton paleoecology

Phytoplankton assemblages in shallow marine environments are being impacted by anthropogenic climate change, but long-term outcomes of these changes are uncertain. Investigation of past neritic calcareous nannoplankton can help us understand the fate these ecosystems face. In this study, a Canonical Correspondence Analysis (CCA) of calcareous nannofossils and X-ray fluorescence geochemistry was used to determine how past planktonic ecosystems were influenced by paleoenvironmental parameters on the eastern side of the Late Cretaceous Western Interior Seaway in the Cenomanian (ca. 95–93 Ma). Samples were collected every 10 cm from the Graneros Shale Greenhorn Formation at an outcrop in northwestern Iowa to determine high resolution changes in assemblages and paleoenvironments. Nannofossil diversity outside of a few small intervals ranges is high (generally 30–60 species) with abundant small Biscutum constans, confirming other publications that show elevated diversity in Cretaceous nearshore settings. The CCA results imply assemblages were most influenced by terrigenous influence, wet vs. dry climate, and changes in water mass source. Cretaceous nannofossil paleoecology was also revised based on the CCA results. Size differentiation of nannofossil taxa may highlight more complexity in environmental preferences that have been largely overlooked. After the initial transgression of the Greenhorn Sea into the region, the climate became wetter and terrigenous influence in the area was high. The peak of terrigenous influence corresponds with elevated nannofossil diversity but a lack of microfauna, which may indicate a similar oceanographic setting to the modern Gulf of Mexico nearshore dead zone. As sea level continued to rise above this point, nannoplankton assemblages indicate a potential shift to a higher productivity, stratified water column. As the muddy Graneros Shale transitioned to a further offshore chalky Greenhorn Formation, a normal marine, cosmopolitan nannofloral assemblage became established. Nannofossil and geochemical evidence indicates high productivity from upwelling might be related to the change of deposition to chalk in the Greenhorn Formation. While only a single outcrop was investigated, the novel use of an integrated micropaleontological and geochemical analysis has shed light on the dynamics of how phytoplankton ecosystems were established and modified in shallow marine environments of the Cretaceous and could have important implications on modern shallow marine settings.

Stopping the Spread: How Blame Attributions Drive Customer-to-Customer Misbehavior Contagion and What Frontline Employees Can Do to Curb It.

Service encounters nowadays are increasingly characterized by customer-to-customer (C2C) interactions where customers regularly become targets of other customers' misbehavior. Although previous research provides initial evidence of the contagiousness of such C2C misbehavior, it remains unclear whether, how, and why C2C misbehavior spreads when frontline employees (FLEs) are involved and what FLEs can do to curb it. Two online and one field experiment in the context of co-working and transportation services reveal that FLE-directed blame attributions drive the spread of C2C misbehavior while perpetrator-directed blame attributions reverse it. These blame attributions are greater the more severely customers judge other customers' misbehavior. Findings further rule out alternative contagion mechanisms (social norms and emotional contagion) and show that contagion spills over to C2C misbehavior unrelated to the initial transgression. By specifying how contagion unfolds and by explicating the central role blame attributions play in C2C misbehavior contagion, this research uncovers its social dynamics, thus extending existing theory on customer misbehavior and attribution theory in multi-actor settings. Managerially, this research provides FLEs with explicit guidance on what they should do (personalized FLE interventions delivered either in person or remotely) and avoid doing (disapproving looks, FLE service recovery) when faced with C2C misbehavior.

Dynamic environmental conditions recorded by the trace fossil Teichichnus and event beds during deposition of the basal Vaca Muerta Formation in the central Neuquén Basin (Argentina)

The mud-dominated part of the basal Vaca Muerta Formation in the central Neuquén Basin accumulated mainly under dysoxic conditions as indicated by the absence of both fine lamination and large burrows, typical of anoxic and oxic conditions, respectively. Event beds and large, strata-bound concretions preserving a nearly uncompacted sediment fabric document rather discontinuous deposition, in particular as concretions must reside within the zone of carbonate supersaturation for a prolonged period of time to form. The mudrock hosts numerous ash layers. Among them is a bed up to 40 cm-thick that was deposited by storm-induced currents and later became calcified. It contains abundant, winding Teichichnus up to 220 cm-long. The trace producers partly reworked their own spreite and probably applied a gardening and sequestrichnial nutritional strategy (that is collecting and stowing of nutritional material in the burrow for later utilization). The spreite fill documents depositional processes that delivered argillaceous sediment and provided oxygen. The ash originally constituting the Teichichnus bed originated from the volcanic arc west of the basin. In contrast, the erosive surface limiting the Teichichnus bed is covered by mud, implying sediment delivery from the east or south where rivers entered the basin while the climate was (at least seasonally) humid, whereas aridity increased towards the north. Consequently, an estuarine circulation likely developed and prevailed during the initial transgression of the lower Vaca Muerta Formation while cold Palaeo-Pacific water flowed into the subsiding and expanding basin. Later, during prevailing dry climate, an anti-estuarine circulation was probably established.

Deposition of sandstone (early Cambrian) above the Great Unconformity in the Sino-Korean Block, Gondwana: Control of antecedent topography

The global transition between the Precambrian and Phanerozoic eons in concert with rise in eustatic sea-level caused an important change in paleoenvironments, represented by sedimentary records above the Great Unconformity. In the Sino-Korean Block, Gondwana, the unconformity has been recognized by a boundary between various basement rocks and the overlying distinctive suite of sandstone (including conglomerate, conglomeratic sandstone, and mudstone) of the early Cambrian age. A plate tectonic reconstruction of the Cambrian-Ordovician succession in the northeast Asian continent reveals that the sandstone deposited largely in the eastern part of the platform (North China Platform), including the Taebaeksan and Pyeongnam basins. In the western part of the platform, the basal sandstone is correlated to basal carbonate rocks of middle Cambrian age, forming a time-transgressive or diachronous unconformity. The disparity in sedimentary facies of the basal deposits overlying the Great Unconformity was primarily due to antecedent topography of the bounding continent: in the eastern platform, the drainage area comprised high-relief Precambrian massifs, whereas in the western part, it comprised low-relief massifs. During the initial stage of sea-level rise, the eastern part of the platform formed progressively open shoreface and foreshore environments with localized embayments in which relatively coarse-grained gravelly sandstone deposited in fan-delta and tide-dominated environments. In the western platform, however, the supply of siliciclastic sediments was limited and the sandstone formed a relatively narrow linear belt of delta and distributary mouth bars and foreshore deposits. In the rest of the platform farther west, accommodation created by subsequent sea-level rise was filled with carbonate sediments. This study demonstrates that antecedent topography of the unsubmerged drainage area played a major role for the deposition of sandstone in the initial transgression stage, forming the Great Unconformity.

The Devonian-Carboniferous transition at Borkewehr near Wocklum (northern Rhenish Massif, Germany) – a potential GSSP section

The Borkewehr section near Balve at the southeastern end of the Remscheid-Altena Anticline is currently the best and most complete Devonian/Carboniferous Boundary (DCB) succession of the Rhenish Massif, Germany. Based on a multidisciplinary approach, focusing on refined conodont and ammonoid biostratigraphy, microfacies analyses, sequence stratigraphy, carbon isotopes (Corg and Ccarb), trace element geochemistry, including REE data, and cyclostratigraphy, the section is proposed as a candidate for the new basal Carboniferous GSSP. The succession represents a pelagic “seamount” setting. It spans the upper Famennian to lower Viséan, with a condensed development of most Rhenish lithostratigraphic units and sedimentary sequences. It is the type-section of the oxic and strongly cyclic, fossiliferous Wocklum Limestone and of important uppermost Famennian and basal Carboniferous index species. The First Appearance Datum (FAD) of Protognathodus kockeli s.str., in a phylogenetic succession from the ancestral Pr. semikockeli n. sp., is proposed as future GSSP level. This FAD is sandwiched between many other marker levels for global correlation. Below are, from base to top, the transgressive base of the at least partly anoxic Hangenberg Black Shale (base Lower Hangenberg Crisis Interval), the Hangenberg Regression (onset of siltstones of the basal Middle Crisis Interval), the level of maximum regression, indicated by maximum Zr/Al values, and the initial transgression of the basal Upper Crisis Interval, marked by the re-onset of carbonate deposition. Above follow the locally cryptogenic FAD of Siphonodella (Eosiphonodella) sulcata s.l. at the base of the post-Crisis Interval (Hangenberg Limestone), associated with a conodont biofacies shift, the FAD of Si. (Eo.) bransoni, and, much higher, the sharp Lower Alum Shale Event at the base of the classical middle Tournaisian. The significance of the section is greatly enlarged by its precise correlation with numerous other Rhenish DCB sections that provide important additional data on faunas, geochemistry, geochronological ages, and magnetic susceptibility. The new Borkewehr data suggest changes of weathering intensity, based on Rb/K and K/Al trends, and Milankovitch cyclicity associated with the climate changes of the Hangenberg Crisis. The local conodont extinction rate at the top of the Wocklum Limestone lies at 57 % while there are no survivors in ammonoids, trilobites, or deep-water corals. Positive carbon isotopic shifts of carbonate in the Upper Crisis Interval and of Corg in the Middle Crisis Interval are decoupled, which suggests complex underlying processes that are not yet understood.

Earliest Ediacaran speleothems and their implications for terrestrial life after the Marinoan snowball Earth

Cryogenian snowball Earth glaciations may have had disastrous impacts on the biosphere, particularly the terrestrial ecosystem. However, how the terrestrial ecosystem responded to and recovered from these glaciations remains poorly understood. Speleothems offer important insights into terrestrial life because their formation is critically dependent on soil CO2 derived from microbial respiration. Here we report the wide distribution of miniature paleo-speleothems from the ∼ 635 Ma Doushantuo cap dolostone in South China and assess their implications for the recovery of terrestrial life after the terminal Cryogenian Marinoan glaciation. The ∼ 3-m-thick cap dolostone was deposited during the initial transgression following deglaciation but subsequently experienced subaerial exposure due to post-glacial rebound, which resulted in the development of extensive sheet-cavities in the cap dolostone and a widespread karstic surface atop the cap dolostone. The sheet-cavities were filled with multiple generations of minerals, including isopachous dolomite interpreted to have formed in the phreatic zone, speleothems consisting of fibrous calcite interpreted to have formed in the vadose zone, as well as later phases (i.e., isopachous radial chalcedony, crystalline quartz, and blocky calcite). The Doushantuo speleothems are millimeter-to-centimeter in size and include gravitational speleothems (stalactites and stalagmites) and non-gravitational speleothems (helictites, moonmilk, botryoids, and flat crusts). Some of them were secondarily silicified by hydrothermal fluids before a renewed transgression in which ∼ 632 Ma shales overlying the cap dolostone were deposited. The wide distribution of Doushantuo speleothems and the preservation of microfossils in these speleothems indicate the presence of an active soil-microbial ecosystem in the earliest Ediacaran Period and the rapid recovery of terrestrial life after the Marinoan snowball Earth.

The sedimentary succession of the last 2.25 Myr in the Bohai Strait: Implications for the Quaternary paleoenvironmental evolution of the Bohai Sea

The Bohai Strait connects the Bohai Sea with the Yellow Sea, allowing material and energy exchange between the seas. The sedimentary record in this region is important for reconstructing the Quaternary sea-level changes and environmental evolution in the Bohai Sea area; however, long sedimentary sequences with a reliable chronological framework from this area are scarce. We assessed the sedimentary characteristics, grain size, microfossils, accelerator mass spectrometry 14 C ages and optically stimulated luminescence ages of core BHS01 from the Bohai Strait. From these and previous paleomagnetic results, new insights into regional sea-level changes and environmental evolution in the Bohai Strait over the last 2.25 Myr are obtained. The sedimentology and environmental proxies (benthic foraminifera and marine ostracods) indicate that the sedimentary environment of the area around core BHS01 was mainly dominated by fluvial–lacustrine deposits from 2.25 to 0.89 Ma, and subsequently by alternating marine and fluvial deposits. Comparative analyses of the chronological and sedimentary results of core BHS01 with previous drilling records in the eastern marginal seas of China revealed that the Quaternary initial marine transgression of the Bohai Sea occurred no later than 0.89 Ma (latest early Pleistocene) since Quaternary. The initial transgression presumably resulted from the partial subsidence and disintegration of the Miaodao Islands Uplift with sea-level rise during this period or slightly earlier. This result is generally consistent with the timing of the Quaternary regional marine transgressive processes of the Yellow and Bohai seas; thus, we propose a conceptual model in which the first marine transgression of the Yellow Sea and the Bohai Sea during the Quaternary occurred no later than 1.66 Ma and 0.89 Ma, respectively. This study provides new evidence for understanding the Quaternary sea-level changes and regional environmental evolution in the Bohai Sea. • Paleoenvironmental evolution of the Bohai Strait since ~2.25 Ma reconstructed. • Quaternary initial transgression of the Bohai Sea occurred no later than 0.89 Ma. • Conceptual model for Quaternary transgressive processes of the study area proposed.

Early post-rift depositional systems of the Central Atlantic: Lower and Middle Jurassic of the Essaouira-Agadir Basin, Morocco

Passive margins are traditionally regarded as tectonically quiescent, however the increasing recognition of significant post-rift tectonic uplift along their flanks offers an important control on sediment delivery. The most extensive record of the early post-rift succession of the Central Atlantic Margin (CAM) is found in the Lower and Middle Jurassic outcrops of the Essaouira-Agadir Basin (EAB). This important succession is characterised by alternating deposition of marine carbonates and paralic siliciclastics that correlate with periods of tectonic activity along the margin, rejuvenating sediment input to the basin. Field observations, well data and petrographic analysis are integrated into a coherent sedimentological model, correlated across the basin within a sequence stratigraphic framework. Comparison is drawn with equivalent dated units in the Central High Atlas, which allows a constraint on the regional versus local tectonostratigraphic evolution.In the EAB, Upper Sinemurian to Lower Pliensbachian open marine ramp carbonates record an initial transgression. They are only preserved locally in the north of the basin, below a major fluvial erosion surface that is regionally traceable across the basin and incisive into the Pliensbachian, CAMP basalts or Triassic sediments. In the Central High Atlas (CHA), the correlative fluvial erosive event has been dated as Toarcian in age. This influx of siliciclastic sediments is interpreted to have been sourced from the Meseta and/or the Anti-Atlas, supporting recent apatite-fission track thermochronology that indicates erosional exhumation at this time.During the Upper Toarcian, a regional carbonate platform, dominated by peritidal deposits, developed across the EAB in response to renewed marine transgression. Facies include oolitic and bioclastic grainstones, crystalline dolomite, stromatolites and dissolution breccias or evaporites. Overlying Middle Jurassic shallow-marine and fluvial siliciclastics encroached from south of the basin (possibly related to a potential source area in the Anti-Atlas), while to the north shallow marine carbonates dominated. These observations evidence the role of tectonic movements of the hinterland during a passive margin phase as a mechanism to trigger forced regressions, compensating the effect of eustasy.

Cenozoic Sea‐land Transition and its Petroleum Geological Significance in the Northern South China Sea

AbstractThe process of Cenozoic sea‐land changes in the northern South China Sea (SCS) controlled the sedimentary filling pattern and played an important role in the petroleum geological characteristics of the northern marginal sedimentary basins. Under the control of the opening process of the SCS, the northern SCS Cenozoic transgression generally showed the characteristics of early in the east and late in the west, and early in the south and late in the north. The initial transgression occurred in the Eocene in the Taixinan Basin (TXNB) of the eastern SCS, while the transgression occurred until the Pliocene in the Yinggehai Basin (YGHB) of the western SCS. International Ocean Discovery Program (IODP) expeditions (Expeditions 367/368) revealed that the initial transgression of the SCS basin occurred at approximately 34 Ma, which was the initial opening time of the SCS. The period of drastic changes in the sedimentary environment caused by large‐scale transgression corresponded to the opening time of the southwestern subbasin (approximately 23 Ma), which also represented the peak of the spreading of the SCS. The sea‐land transition process controls the distribution of alternating continent‐marine facies, marine facies source rocks and reservoirs in the basins. The marine facies source rocks of the basins in the northern SCS have a trend of gradually becoming younger from east to west, which is consistent with the regional process of gradual transgression from east to west. Regional sea‐level changes were comprehensively influenced by SCS opening and global sea‐level changes. These processes led to the early development in the east and south and late development in the west and north for the carbonate platform in the SCS. Carbonate platforms form another type of “self‐generating and self‐accumulating” oil‐gas reservoir in the northern SCS. The sea‐land transition controlled the depositional filling patterns of different basins and laid the foundation of marine deposits for oil and gas resources. The source‐reservoir‐cap assemblage in the northern SCS was controlled horizontally by provenance supply and sedimentary environmental changes caused by sea‐land transition and vertically by the tectonic evolution of the SCS and regional sea‐level changes.

Original Sin vs. Original Grace: The Adamic Fall and the Primordial Covenant

ABSTRACT The Christian doctrine of original sin—a corollary of the initial Adamic transgression—is the linchpin of the soteriological and eschatological significance of Christ. Construction of a binary opposition between the fall through Adam and redemption through Christ seems pleasing in its symmetry, yet the question of children who die in infancy poses a problem. This article considers the historical positions on this issue and compares them with the Islamic conception of original grace—a state of innate innocence due to the primordial covenant in which all souls attest to the lordship of God before birth. It then uses this concept to shed light on the fate of infants who die before reaching maturity.

Reservoir evaluation within the sequence stratigraphic framework of the Upper Cretaceous Anambra Basin, Nigeria

The Anambra Basin has become a subject of interest in recent years, following renewed search for hydrocarbon in Nigeria's inland sedimentary basins to increase its reserve base. Although there are extensive studies on different hydrocarbon aspects of the basin, there are currently no published studies on the assessment of potential subsurface reservoirs. This study evaluates the reservoir properties of the Upper Cretaceous (Campanian to Maastrichtian) Anambra Basin, within a sequence stratigraphic framework, using wireline-log data. Four depositional sequences (SEQ-1, SEQ-2, SEQ-3, and SEQ-4, from oldest to youngest) were interpreted, each bounded by two sequence boundaries. They span in age from 83 Ma to 63 Ma (20 Myr duration), and overall record an initial transgression, then subsequent regression, aggradation, and final transgression. The cross-plots and computed petrophysical properties suggest that there are significant spatial and temporal variations in reservoir parameters in the basin, with some predictable trends, as shown by generated isoparametric maps. Preliminary assessment further suggests that the main controls on reservoir property variations are the depositional facies, burial depth, and diagenetic processes (compaction and cementation). A new method of ranking the reservoir potential of interpreted depositional sequences showed that the best ranked sequence is SEQ-4 (chance of success, CoS = 0.73/0.9), while the least ranked sequence is SEQ-1 (CoS = 0.45/0.9). This study therefore provides a framework within which additional well data should be made available, to allow a robust assessment of the trends of and controls on the spatio-temporal variations in petrophysical properties, in order to better predict reservoir quality distribution, and guide future exploration in this frontier basin.

Paleo-sedimentary environment in relation to enrichment of organic matter of Early Cambrian black rocks of Niutitang Formation from Xiangxi area China

Abstract Early Cambrian organic-rich black rocks are extensively distributed in the southern China. In this study, we have discussed the relation of paleo-sedimentary environments with enrichment of organic matter. Based on TOC data, we divided the Niutitang Formation into three parts (Upper, Middle, and Lower). The amount of total organic carbon in the Lower (1.55 wt %) and the Upper part (1.35 wt %) of Niutitang Formation is significantly smaller than the Middle part (8.0 wt %) which suggest initial transgression, and regression stages of the sea level respectively. The Middle part from both sections (Longbizui and Sancha) contains higher TOC content, which is a clue of intense transgression stage of sea level with high bio-productivity. Kerogen type index (KTI) using different macerals specify the organic matter in these black rock series is mainly type-I with a minor amount of type-II1. Moreover, these black rocks were deposited in weak to moderately restricted hydrographic conditions. The heterogenic mineral composition was also observed in these black rocks, including quartz, clay, gypsum, pyrite, barite, dolomite, and plagioclase. Quartz content in the Middle part is relatively higher than the Upper, and the Lower part displays a strong positive relation with TOC which suggests the main source of quartz during deposition of the Middle part was biogenic quartz. During Early Cambrian period due to extension between the Yangtze and the Cathaysian plate, the hydrothermal fluids rich in uranium, vanadium, molybdenum, zinc, barium, etc. from the deeper part of the earth crust and entered the ocean basin through extensional remnant fissures and cracks, and due to upwelling phenomena entered to the shelf area. These nutrient-rich deep crustal fluids at the surface of the sea enhanced the evolution and breeding of planktons and other marine life; meanwhile, it upsurges the bio-productivity. Additionally, it creates bottom water hypoxia, which is favourable for the preservation of organic matter in the sedimentary rocks. The main factors responsible for the enrichment of organic matter in these Early Cambrian black rock series of Niutitang Formation were a hydrographic restriction, hydrothermal activities, and paleo-redox conditions, respectively.

Pioneer nannofossil assemblages from the initial transgression of the Niobrara seaway in the Turonian, San Juan Basin, New Mexico, USA

Abstract Nannofossils of the North American Late Cretaceous Western Interior Seaway have been extensively studied, but these investigations have primarily focused on the diverse communities of the Niobrara and Greenhorn sea-level highstands. We lack a firm understanding of the nature of early nannofossil communities from the initial stages of the transgression, and of how the diverse assemblages of the Coniacian–Santonian became established. We investigated nannofossils in a core from the San Juan Basin, New Mexico, with concentrated sampling across this transgression. We then compared nannofossil assemblages from the initial transgression of the seaway to the more established, cosmopolitan assemblages of the Niobrara highstand. The initial stages of transgression were characterized by unusual, low-diversity assemblages dominated by holococcoliths and seldom reported and previously undescribed species of hetero- and holococcoliths. Herein, we describe five new species and one new genus from these assemblages: Ahmuellerella frankiae sp. nov., Gartnerago waszczakii sp. nov., Orastrum schollei sp. nov., Pharus clarescopoli sp. nov., and Wisea sanjuanensis gen. et sp. nov. These initial assemblages transitioned to more cosmopolitan, higher-diversity assemblages, coincident with an unconformity that likely represents subaqueous erosion or prolonged non-deposition. Above this unconformity, the nannoplankton were abundant, diverse, and characterized by open-marine, cosmopolitan taxa that persisted through the Coniacian and Santonian. X-ray fluorescence data collected from the core show a high abundance of the detrital elements Al and Ti in the section, indicating substantial detrital clay input into the area, coincident with deposition of the holococcolith-dominated assemblages. The detrital influence lessened as cosmopolitan nannoplankton became more abundant in the area. We suggest that the initial holococcolith-rich assemblages are representative of a shallow-marine, potentially hyposaline, turbid or unstable environment. Such assemblages have been observed from the Late Turonian elsewhere in northern New Mexico and may represent typical pioneer nannofloras of the Late Cretaceous Western Interior marine transgressions. Our integrated investigation of nannofossils and X-ray fluorescence geochemistry adds to the meager knowledge base of pioneer nannofloral communities in the initial phases of continental marine transgression.

Water level fluctuations in Lake Baringo, Kenya, during the 19th and 20th centuries: Evidence from lake sediments

This article presents a fossil diatom-based, semi-quantitative reconstruction of water level fluctuations for Lake Baringo over the past 200 years as a consequence of climatic variations. A 285 cm long sediment core sample was collected using a Rod-Operated Single-drive Stationary Piston corer. Lake level was inferred using indices based on the proportion of planktonic to benthic diatom taxa (P/B ratio). The sediment archive presented distinct zones dominated by planktonic and benthic diatom flora. An initial transgression in the early 19th century was characterised as a shallow water environment dominated by planktonic Aulacoseira spp. This was a response to extreme drought during the late 18th to early 19th century. Mid-19th century was defined by a high lake stand. The late 19th to early 20th centuries experienced low water level following the widely documented aridity at the time. The mid-20th century was marked by a spectacular rise in water level that coincided with remarkably wet years during the early 1960s and late 1970s. The first decade of the 21st century witnessed widespread changes in water level. The proxy records show that lake ramping and drawdown over the years follow approximately 50-year climatic cycles.

Earliest Cretaceous Transgression of North America Recorded in Thick Coals: McMurray Sub-Basin, Canada

Strata of the Lower Cretaceous McMurray Formation in the McMurray Sub-Basin (MSB) of Alberta and Saskatchewan, Canada, comprise marginal marine, tidal-fluvial, fluvial and interfluve deposits. In the Firebag Tributary located in the northeastern portion of the sub-basin, a thick coal seam (up to >20 m) forms a semi-continuous bed at the top of the lowermost McMurray Fm deposits (herein referred to as Lower McMurray). In coastal plain settings, peat-forming mires are highly sensitive archives of base-level. We investigate the stratigraphic significance of coals in the Firebag Tributary by analyzing coal petrography (4 cores), coal geochemistry (2 cores), and coal distribution in ~4500 wells. Additionally, we record the first absolute age for the McMurray Fm through the dating of an ash layer within the coal seam.The petrographic character and distribution of coals in the northeastern part of the MSB suggest a complex history of base-level rise at the end of Lower McMurray deposition. Wetting-upward character coal seams record initial transgression of the Boreal Sea during a 4th order sea level rise (Milankovitch-scale) within lowstand to early transgressive systems tract conditions. Sea-level rise during Lower McMurray times was estimated based on temperate climate peat formation rates, as well as peat-to-coal compaction factors, and probably occurred on a scale of 0.5–3 mm a−1. Seam-internal wetting-upward cycles suggest that base-level rise was punctuated. Locally, compound and drying-upward character coals represent zones of high accommodation, wherein peat accumulation in mires was influenced by phases of syn-depositional subsidence and karst collapse. The thickest coals in the study area form an arc on a coastal plain as the Boreal Sea inundated east- to southeastward into the Firebag Tributary. Within the arc of thick coals, a north-south decrease in coal thickness is interpreted to reflect the general southward inundation of the Boreal Sea across the MSB. Exceptionally thick coals (>10 m) likely formed where basement processes (e.g., karsting in Devonian carbonates) provided preferential groundwater pathways.Chemical abrasion thermal ionization mass spectrometry dating of 5 sharply faceted zircons recovered from an ash bed within the coal provides the first absolute age (121.39 ± 0.2 Ma – Aptian) to the southward transgression of the Boreal Sea. We hypothesize that initial inundation of the MSB was related to tectonic activity in the Canadian Cordillera and the onset of magmatic flow in the western Coast Plutonic Complex.

The Modified Temptation Resistance Task: A Paradigm to Elicit Children's Strategic Lie-telling

The protocol for the temptation resistance paradigm was designed to elicit 2- to 8-year-old children's strategic lie-telling behaviors. The reward of transgression was intended to be too tempting to resist, so that children's spontaneous lie-telling behavior in the presence of irreversible evidence due to the transgression could be observed. Conducted in a developmental psychology laboratory behind a one-way mirror and video recorded with a hidden camcorder, the protocol starts with a guessing game where the child is given three trials to guess the identities of hidden objects under an upside down cup. The experimenter gives hints in the first two trials to make sure the child "guess" them correctly. At the beginning of the final trial, the experimenter leaves the room briefly and asks the child not to peek under the cup. If the child could not resist the temptation and peeks, small particles previously filled in the cup would scatter on a grooved surface. Upon the experimenter's return, the child is asked if he/she has peeked. If he/she denies transgression contrary to the presence of the physical evidence, he/she is asked to explain why the particles are on the table. Three responses could be observed in the procedure, including the initial transgression, truth-telling or lie-telling behavior if the child peeked, and the strategic lie-telling behavior in the presence of the physical evidence.

The Modified Temptation Resistance Task: A Paradigm to Elicit Children's Strategic Lie-telling.

The protocol for the temptation resistance paradigm was designed to elicit 2- to 8-year-old children's strategic lie-telling behaviors. The reward of transgression was intended to be too tempting to resist, so that children's spontaneous lie-telling behavior in the presence of irreversible evidence due to the transgression could be observed. Conducted in a developmental psychology laboratory behind a one-way mirror and video recorded with a hidden camcorder, the protocol starts with a guessing game where the child is given three trials to guess the identities of hidden objects under an upside down cup. The experimenter gives hints in the first two trials to make sure the child "guess" them correctly. At the beginning of the final trial, the experimenter leaves the room briefly and asks the child not to peek under the cup. If the child could not resist the temptation and peeks, small particles previously filled in the cup would scatter on a grooved surface. Upon the experimenter's return, the child is asked if he/she has peeked. If he/she denies transgression contrary to the presence of the physical evidence, he/she is asked to explain why the particles are on the table. Three responses could be observed in the procedure, including the initial transgression, truth-telling or lie-telling behavior if the child peeked, and the strategic lie-telling behavior in the presence of the physical evidence.