Carbonates

The Upper Mississippian Chesterian Ste Genevieve and Paoli Formations of the Illinois basin are composed of five carbonate and
mixed carbonate siliciclastic fourth order 100500 k y sequences Interpretive cross sections based on detailed measured sections of 57 closely
spaced outcrops and cores show that sequence bounding carbonate and siliciclastic paleosol horizonsand distinctive marker beds canbe correlated
basin wide within the available biostratigraphic framework Each sequence is composed of as many as nine regionally developed parasequences
Carbonate parasequences have patchy updip carbonate eolianites at the base overlain by laterally discontinuous ooid tidal ridge and skeletal bank
facies and laterally extensive muddy carbonate caps Mixed carbonate siliciclastic parasequences are composed of skeletal limestone capped by fos
siliferous shale Carbonate tidal flat facies are rare in the succession
The sequences were produced by moderate amplitude fourth order 100500 k y glacio eustatic sea level changes whereas the parasequences
were likely produced by fifth order 10100 k y glacio eustatic sea level changes during atime of transition from the greenhouse conditions of the
Early Mississippian to the icehouse conditions of the late Paleozoic This transition is reflected in upward change from carbonate dominated dis
conformity bounded sequences with little lowstand erosion at thebase to mixed carbonate clastic sequences with significant lowstand erosion at the
top of the study interval and in overlying sequences These changes were likely caused by an increase in the magnitude of sea level fluctuations cou
pled with increasingly humid wet dry seasonal climate The sequences may be stacked into one ortwo third order 0 5 5 m y composite sequences
that are bounded by relatively well developed unconformities However the magnitude of lhe fourth order signal makes third order bundling less
clear than in strata deposited during greenhouse times of lower amplitude fourth and fifth order sea level fluctuations The dominance of fourth
order disconformity bounded sequences and the lack of regional tidal flat facies reflect moderate amplitude eustasy associated with the transition
from global greenhouse climates of the Early Mississippian to times of abundant global ice in thelate Paleozoic

The objective of the current study was to develop and validate a simple, precise and accurate isocratic stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) assay method for the determination of spironolactone and furosemide in solid pharmaceutical dosage forms. Isocratic RP-HPLC separation was achieved on an SGE 150 × 4.6 mm SS Wakosil II 5C8RS 5-μm column using a mobile phase of acetonitrile-ammonium acetate buffer (50:50, v/v) at a flow rate of 1.0 mL/min. The detection was carried out at 254 nm using a photodiode array detector. The drug was subject to oxidation, hydrolysis, photolysis and heat to apply stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness and solution stability. The method was found to be linear in the drug concentration range of 40-160 µg/mL with correlation coefficients of 0.9977 and 0.9953 for spironolactone and furosemide, respectively. The precision (relative standard deviation; RSD) among a six-sample preparation was 0.87% and 1.1% for spironolactone and furosemide, respectively. Repeatability and intermediate precision (RSD) among a six-sample preparation were 0.46% and 0.20% for spironolactone and furosemide, respectively. The accuracy (recovery) was between 98.05 and 100.17% and 99.07 and 100.58% for spironolactone and furosemide, respectively. Degradation products produced as a result of stress studies did not interfere with the detection of spironolactone and furosemide; therefore, the assay can be considered to be stability-indicating.

Dedicated to Professor Dr Jochen Hoefs on the occasion of his 75th birthday Oxygen isotope fractionations in double carbonates of different crystal structures were calculated by the increment method. Synthesis experiments were performed at 60 °C and 100 °C to determine oxygen and carbon isotope fractionations involving PbMg[CO 3 ] 2. The calculations suggest that the double carbon-ates of calcite structure are systematically enriched in 18 O relative to those of aragonite and mixture structures. Internally consistent oxygen isotope fractionation factors are obtained for these minerals with respect to quartz, calcite and water at a temperature range of 0–1200 °C. The calculated fractionation factors for double carbonate–water systems are generally consistent with the data available from laboratory experiments. The experimentally determined fractionation factors for PbMg[CO 3 ] 2 , BaMg[CO 3 ] 2 and CaMg[CO 3 ] 2 against H 2 O not only fall between fractionation factors involving pure carbonate end-members but are also close to the calculated fractionation factors. In contrast, experimentally determined carbon isotope fractionation factors between PbMg[CO 3 ] 2 and CO 2 are much closer to theoretical predictions for the cerussite–CO 2 system than for the magnesite–CO 2 system, similar to the fractionation behavior for BaMg[CO 3 ] 2. Therefore, the combined theoretical and experimental results provide insights into the effects of crystal structure and exchange kinetics on oxygen isotope partitioning in double carbonates.

We have synthesized inorganic micron-sized filaments, whose microstucture consists of silica-coated nanometer-sized carbonate crystals, arranged with strong orientational order. They exhibit noncrystallographic, curved, helical morphologies, reminiscent of biological forms. The filaments are similar to supposed cyanobacterial microfossils from the Precambrian Warrawoona chert formation in Western Australia, reputed to be the oldest terrestrial microfossils. Simple organic hydrocarbons, whose sources may also be abiotic and indeed inorganic, readily condense onto these filaments and subsequently polymerize under gentle heating to yield kerogenous products. Our results demonstrate that abiotic and morphologically complex microstructures that are identical to currently accepted biogenic materials can be synthesized inorganically.

levels (that is, greater than 10 25 times that of the present atmospheric level) during the deposition of these units. The presence of rounded pebbles of sideritic iron formation at the base of the Rooihoogte Formation and an extensive and thick ironstone layer consisting of haematitic pisolites and oolites in the upper Timeball Hill Formation indicate that atmospheric oxygen rose

The influence of ionic substituents in calcium phosphates intended for bone and tooth replacement biomedical applications is an important research topic, owing to the essential roles played by trace elements in biological processes. The present study investigates the mechanical and biological evaluation of ionic doped hydroxyapatite/β-tricalcium phosphate mixtures which have been prepared by a simple aqueous precipitation method. Heat treating the resultant calcium phosphates in a carbonated atmosphere led to the formation of ionic doped carbonated hydroxyapatite/β-tricalcium phosphate mixtures containing the essential ions of biological apatite. The structural analysis determined by Rietveld refinement confirmed the presence of hydroxyapatite as the main phase, together with a considerable amount of β-tricalcium phosphate. Such phase assemblage is essentially due to the influence of substituted ions during synthesis. The results from mechanical tests proved that carbonate substitutions are detrimental for the mechanical properties of apatite-based ceramics. In vitro proliferation assays of osteoblastic-like cells (MC3T3-E1 cell line) to powders revealed that carbonate incorporation can either delay or accelerate MC3T3 proliferation, although reaching the same proliferation levels as control cells after 2 weeks in culture. Further, the powders enable pre-osteoblastic differentiation in a similar manner to control cells, as indirectly measured by ALP activity and Type-I collagen medium secretion.

The mummification ritual in ancient Egypt involved the evisceration of the corpse and its desiccation using natron, a naturally occurring evaporitic mineral deposit from the Wadi Natrun, Egypt. The deposit typically contains sodium carbonate, sodium bicarbonate and impurities of chloride and sulfate as its major elemental components. It is believed that the function of the natron was to rapidly remove the water from the cadaver to prevent microbial attack associated with subsequent biological tissue degradation and putrefaction. Several specimens of natron that were recently collected from the Wadi Natrun contained coloured zones interspersed with the mineral matrix that are superficially reminiscent of extremophilic cyanobacterial colonisation found elsewhere in hot and cold deserts. Raman spectroscopy of these specimens using visible and near-infrared laser excitation has revealed not only the mineral composition of the natron, but also evidence for the presence of cyanobacterial colonies in several coloured zones observed in the mineral matrix. Key Raman biosignatures of carotenoids, scytonemin and chlorophyll have been identified. Figure The mummification ritual in ancient Egypt involved the evisceration of the corpse and its desiccation using natron, a naturally occurring evaporitic mineral deposit from the Wadi Natrun, Egypt. The deposit typically contains sodium carbonate, sodium bicarbonate and impurities of chloride and sulfate as its major elemental components. It is believed that the function of the natron was to rapidly remove the water from the cadaver to prevent microbial attack associated with subsequent biological tissue degradation and putrefaction. Several specimens of natron that were recently collected from the Wadi Natrun contained coloured zones interspersed with the mineral matrix that are superficially reminiscent of extremophilic cyanobacterial colonisation found elsewhere in hot and cold deserts. Raman spectroscopy of these specimens using visible and near-infrared laser excitation has revealed not only the mineral composition of the natron, but also evidence for the presence of cyanobacterial colonies in several coloured zones observed in the mineral matrix. Key Raman biosignatures of carotenoids, scytonemin and chlorophyll have been identified.

Agarose can be activated by adding cyanogen bromide, dissolved in acetonitrile, to beads suspended in a solution of sodium carbonate. The necessity for manual titration and the use of a pH meter are thus eliminated. Activation for 1 min results in coupling capacities comparable to those reported for the titration method. The coupling capacity is influenced by the initial carbonate concentration and by the duration and temperature of the activation reaction. The coupling capacities of the activated gels are very reproducible.

ABSTRACT: Forensic anthropologists use a number of maceration techniques to facilitate skeletal analysis of personal identity and trauma, but they may unwittingly eliminate valuable DNA evidence in the process. This study evaluated the effect of 10 maceration methods on gross bone structure and the preservation of DNA in ribs of 12 pigs (Sus scrofa). A scoring system was applied to evaluate the ease of maceration and resulting bone quality while DNA purity was quantified by optical densitometry analysis, followed by polymerase chain reaction (PCR) amplification of three mitochondrial and three nuclear loci. The results demonstrated that while mitochondrial DNA could be amplified for all experiments, cleaning treatments using bleach, hydrogen peroxide, ethylenediaminetetraacetic acid/papain, room temperature water and detergent/sodium carbonate followed by degreasing had low DNA concentrations and failed to generate nuclear PCR products. In general, treatments performed at high temperatures (90°C or above) for short durations performed best. This study shows that traditionally “conservative” maceration techniques are not necessarily the best methods to yield DNA from skeletal tissue.

Pour la caractérisation pétrophysique et pétrographique des roches du système mixte carbonaté, siliciclastique et évaporitique du Desmoinesien supérieur du Bassin du Paradox (Utah, USA), trois affleurements de terrain et six carottes de forage ont été visités. Les données pétrophysiques mesurées sur échantillon sont la densité, la porosité, la perméabilité, et les vitesses ultrasoniques des ondes P et S. Pour la pétrographie, les observations en lame mince (texture, composants, porosité, types de pores et diagenèse) sont complétées par la minéralogie en diffraction X. Ce travail débouche sur deux applications. D'une part, la base de données constituée permet de mieux comprendre les propriétés pétrophysiques en relation avec la pétrographie. D'autre part, la calibration pétrophysique en laboratoire a servi pour mettre au point une méthode de prédiction de lithofaciès et faciès pétrophysiques. Cette technique, basée sur des statistiques multivariées classiques, permet d'interpréter les diagraphies de puits en intervalles non carottés.

For petrophysical and petrographic characterization of rocks from the mixed carbonate, siliciclastic and evaporite system of Upper Desmoinesian in Paradox Basin (Utah, USA), three outcrops and six drilling cores have been visited.  Petrophysical data measured on rock samples are density, porosity, permeability, and ultrasonic P- and S-wave velocities.  Regarding petrography, thin section observations (texture, components, porosity, pore types and diagenesis) are complemented by X-ray diffraction mineralogy.  This work results in two applications.  On one hand, the dataset that has been built allows to better understand the development of petrophysical properties in relation with petrography.  On the other hand, petrophysical calibration in the laboratory serves to establish a method to predict lithofacies and petrophysical facies.  This technique, based on classical multivariate statistics, allows to interpret wellbore logs along uncored intervals.

Our objective is to demonstrate the analytical capabilities of Advanced Surface Logging or Advanced Mud Logging (AML), the results borne from an extensive use of wellsite techniques and their use in time-critical situations. The work revolves around ascertaining and characterizing from the surface the nature of fluids found downhole using a number of integrated analytical techniques on oil samples and rock cuttings. We aim to evaluate the reservoir fluid properties flowing from the fractures and fluids which are suspected to be present within the pores of the reservoir matrix via cross-referencing multiple sample mediums.
The work studies data collected from a well in the Middle East; “Well-A”, which was drilled as a producer from the Upper-Middle Jurassic (UMJ) Formations and an appraisal from the porous interval of the Lower Jurassic formation (LJ). The primary target of the operating company was to determine the in-situ fluid characteristics of the UMJ Formations. The communication between these two intervals as well as the contact depth is unknown and crucial at the current stage of the field development.
Reservoir and hydrocarbon fluid characterization was investigated using cuttings samples taken from Well-A. All samples were analyzed in-lab, post-drilling using Advanced Mudlogging (AML) techniques such as Thermal Extraction Gas Chromatography (TEGC), Chemical Elemental Analysis and Mineralogical analysis (the latter two performed using X-Ray based techniques). Additional Mudlogging datasets gathered in real-time during drilling were integrated within the interpretation including Advanced Mud Gas (Methane to Toluene), together with the Computer Processed Image Logs and PVT test data provided by the operator. Finally, three dead oil samples from the tested intervals were analyzed in-lab with TEGC.
The chromatographic analysis of the commercially produced oil from the UJ showed a bimodal distribution which was interpreted as a mix of two different maturity fluids. We were able to trace the individual levels from which these two fluids were most probable to originate, by comparing the chromatographic characteristics of these oils across the TEGC results from the cuttings analysis. Furthermore, the in-lab geochemical analysis supported the understanding of the fluid mechanism within this reservoir interval. This interpretation resulted in potentially identifying a sub interval which could yield a higher gravity oil than initially tested and potentially transform this, now unproductive interval, into a prospect.
The innovative workflow, integrating all formation evaluation data collected from rock cuttings and mud gas data was applied for the first time at this level of complexity. Although prior studies investigated thepotential of integrating multiple datasets to determine reservoir fluid characteristics, never before, was such an integrated approach utilized based specifically on surface logging solutions. The case study demonstrated the value of supporting interpreters to bolster their interpretations thanks to data coming from separate independent sources.

Cathodoluminescent petrography (CL) is a well established technique that can provide a means to examine fabrics, diagenetic phases and cement relationships in sedimentary rocks.  CL is very useful in the study of carbonate rocks because of the activators and quenchers.  Mn is the most important CL activator in carbonate minerals and concentrations of ca. 20 ppm can cause luminescence, although levels of just a few ppm may be enough to cause weak CL depending on the amount of Fe present.  Fe begins to quench luminescence at levels of ca. 200 ppm, and effectively quenches luminescence at levels of 103 ppm.  Mn and Fe both have divalent reduced forms that readily fit into trigonal carbonate crystal structures and they have different redox potentials, so the concentration of these cations provide a baseline for understanding oxygen levels of the pore fluids from which the carbonate precipitated.
Dolomite is an important sedimentary mineral that can be difficult to interpret because many dolostones are composed of multiple stages of dolomite that typically represent very different geochemical processes of replacement, recrystallization, and cementation.  Because these processes usually occur under different redox conditions, dolomites record these changes in their crystals.  Dolomites of the Permian Phosphoria Complex provide an excellent case example that contains petroleum source rocks in basinal facies and petroleum reservoir rocks in shallow water peritidal carbonate facies.  The shallow water facies were subjected to extreme arid conditions and evaporation that led to an early mimetic dolomitization of CaCO3 sediments.  This first phase experienced recrystallization and overprinting by burial phases that also are major cementing phases. Cement recognition is important in carbonate rocks, and especially dolomite, because of its importance in determining the hydrologic properties of carbonate aquifers and petroleum reservoirs.

Field outcrop and petrographic data were used to infer the geologic history and depositional environment of the sediments in Akpagher, in Gboko Local Government Area of Benue State, Nigeria. The method of investigation involved field studies and
sample collection from different outcrop locations. This was followed by laboratory studies involving granulometric and petrographic analyses. The textural analysis data indicates that the sandstones are fine grained with mean size of 2.0 to 2.3mm. The sorting ranges from 1.49 to 1.51 which implies very poorly sorted to poorly sorted sediments. The depositional environment discrimination and bivariate plots reveal a fluvially
influenced shallow marine environment. Also, the presence of bioclasts of oscracods and molluscs in the limestones indicates shallow marine and low energy depositional environment. This was gotten from petrographic analysis on the limestones, which also reveals micrite as the dominant matrix with skeletal fragments, pelloids, and recrystallized bioclasts. The dominance of mud matrix in the limestones indicates proximity to shoreline and low energy, shallow marine deposits. The depositional environment is thus inferred to be probably lagoonal.

El origen y formación de las dolomitas ha sido un enigma por parte de la comunidad científica en las últimas décadas. En este trabajo de investigación, se llevó a cabo un estudio geoquímico de una secuencia litoestratigráfica de diversas facies de calizas macrofosilíferas y dolomitas, correspondientes al Miembro Punceres de la Formación El Cantil en La Cantera El Vivero, Sector Pertigalete, Edo. Anzoátegui - Venezuela, con el propósito de establecer su origen, las condiciones paleoambientales presentes durante la depositación y su evolución diagenética durante el tiempo geológico. Para cumplir con los objetivos planteados, se colectaron un total de once (11) muestras de roca; de modo que, diez (10) correspondían al Miembro Punceres (Fm. El Cantil), y una (1) al posible Miembro Caripe (Fm. Chimana). A cada muestra de roca se les realizó una previa descripción macroscópica, un análisis instrumental por Fluorescencia de Rayos-X (FRX) para determinar la concentración elemental de Al2O3, SiO2, K2O y V (ppm), y un posterior análisis químico por valoración complexométrica con EDTA (ácido etilendiamino-tetraacético) con el propósito de determinar la concentración elemental de MgO, CaO, MnO y Fe2O3. Por medio de la interpretación de los datos obtenidos a partir del levantamiento litoestratigráfico, se definieron tres (3) unidades informales, correspondientes al Miembro Punceres (Fm. El Cantil) (Unidad I y II) y al posible Miembro Caripe (Fm. Chimana) (Unidad III). Asimismo, se identificó la presencia de cuatro (4) facies de carbonatos dentro de las unidades informales I y II: 1) Mudstones diagenética o Cementstone; 2) Floatstone diagenética; 3) Rudstone diagenética; 4) Dolomicrosparstone; de las cuales, se estableció que el posible ambiente de depositación del Miembro Punceres se vincula a un evento de evolución progresiva de un complejo arrecifal rudístico, dentro de un margen de plataforma interna o semi-protegido por algún banco o montículo arrecifal, bajo condiciones ligeramente anóxicas, condicionado por eventos episódicos de transgresión y regresión marina; aunque también, se estableció la posible hipótesis de que algún evento tectónico posterior pudo haber afectado dicha secuencia carbonática, separando la misma en dos entes distintos (Unidad I y II). Por otra parte, en la Unidad III se identificó solo una facies de carbonato: 1) Mudstone pelágica; estableciendo un entorno de depositación más anóxico y de mayor profundidad en esta unidad, posiblemente, dentro del margen de plataforma externa. A través del análisis geoquímico se determinó que las dolomitas del Miembro Punceres, posiblemente, se originaron durante una diagénesis de soterramiento, a través de la filtración por reflujo de aguas de alta salinidad ricas en Mg y, quizás, por influencia de aguas de formación modificadas por la interacción agua-roca de origen sedimentario. Dichas dolomitas presentaron elevadas concentraciones de Fe2O3, MnO y V, a comparación de las calizas, indicando la evidencia de posibles fluidos dolomíticos enriquecidos en Fe2+, Mn2+ y VO2+, bajo condiciones ligeramente anóxicas; estableciendo niveles más anóxicos en los fluidos diagenéticos que originaron la capa de dolomita M2 - M3 (Unidad I), a comparación de la capa de dolomita M7 (Unidad II). Asimismo, en bases a las relaciones elementales MgO/CaO y MnO/CaO, se estableció una posible dolomitización más avanzada y más completa en la capa de dolomita M7. La baja concentración de K2O y CaO y el aumento de MgO, MnO y Fe2O3 en las capas de dolomitas, indica una posible sustitución iónica o reemplazo y recristalización durante el avance diagenético; sin embargo, las concentraciones de K2O en las capas de dolomitas M2 - M3 y M7 y la capa de caliza M1 (Unidad I) se vinculan con mayor criterio a un aumento en la salinidad en la plataforma carbonática; aunque también, se estableció que las elevadas concentraciones de K2O en las capas de calizas M4 a M11 (Unidad I, II y III) se debe, principalmente, a la presencia de minerales arcillosos, destacado por la contenido significativo de SiO2 y Al2O3 en las mismas.

En este trabajo se resumen la geología, génesis, geología económica, geoquímica y ejemplos de los principales minerales tipo Na-Carbonatos, Na-Sulfatos y sales de alumbre en ambientes sedimentarios y magmáticos en algunos casos. Se exponen los principales depositos a nivel mundial. Los carbonatos de sodio son evaporitas que se forman en ambientes ricos en carbonato y bicarbonato y pobres en calcio y magnesio. El uso de carbonato de sodio natural ha ido aumentando con el tiempo sin embargo aún se produce mucho (la mayoría) carbonato de sodio de forma sintética. Para entender la génesis de estos depósitos es necesario el conocimiento de la evolución geoquímica de las soluciones. Las diferentes especies minerales precipitarán de acuerdo a la concentración de CO 2 y la temperatura. La thenardita y mirabilita son la principal fuente de sulfato de sodio, su ambiente de formación y aplicaciones son similares a las de los carbonatos de sodio. Las sales de alumbre son un gran grupo de dobles sales hidratadas con un cation monovalente y otro trivalente. El alumbre tiene un importante uso en la industria textil, cosmética, culinaria, es usado como retardante de llama, floculante químico, en taxidermia, en medicina y para la manufactura de pinturas. ´ Indice 1. Na-Carbonatos 1 2. Na-Sulfatos 5 3. Sales de alumbre 7 4. Referencias 8 1. Na-Carbonatos La "ceniza de soda" N a 2 CO 3 es un material alta-mente utilizado en la industría química y metalúrgi-ca. El carbonato sodico al ser agregado al acero du-rante el proceso de "tostado" disminuye el contenido de azufre y fosforo de la aleación. En la fabricación de detergentes es indispensable ya que asegura el co-rrecto funcionamiento del resto de sustancias que lo componen, durante las diferentes fases del lavado. Se usa tambien como regulador de pH de diferentes so-luciones como por ejemplo en el tratamiento de aguas industriales así como en procesos en cerámica, como ablandador de aguas duras, refinación de petróleos, producción de aluminio, textíles, papel, producción de soda cáustica, disminución del punto de fusión del silicio, etcétera. Es una sustacia altamente alcalina, 300 gramos de carbonato de sodio en cada 50 me-tros cúbicos de agua aumenta 0.1 puntos el valor del pH. Según el USGS (2017), la distribución del uso de la ceniza de soda para el año 2016 fue: vidrio, 50 %; químicos, 28 %; distribuidores, 6 %; jabon y de-tergentes, 6 %; desulfuración de gas de combustión, 1

Aspek mikrofasies dan diagenesis batuan karbonat Anggota Batugamping Formasi Pamutuan telah dipelajari guna mengetahui mekanisme pengendapan batuan dan sejarah proses geologi paska pengendapan batuan. Sampel-sampel batugamping yang telah diambil secara sistematis berdasarkan pada runtunan stratirafi hasil pengukuran penampang stratigrafi rinci pada formasi batuan yang berumur Miosen Tengah tersebut dan telah dipakai untuk bahan pengujian petrografi di laboratorium. Analisis petrografi telah dilakukan terhadap empat belas sampel batugamping yang memperlihatkan bahwa jenisnya adalah wackestone, packstone, grainstone, floatstone, rudstone, dan framestone. Lingkungan pengendapan batuan karbonat Anggota Batugamping Formasi Pamutuan tersebut meliputi fasies landaian laut dalam, tepian cekungan, lerengan terumbu depan, dan terumbu organik di tepi paparan. Beragam proses diagenesis yang terjadi pasca pengendapan batuan yang meliputi : penyemenan, pemikritan, pemampatan, neomorfisme, dan pelarutan.

The sedimentary successions exposed in northeast Calabria document the Jurassic–Early Cretaceous tectonic– sedimentary evolution of a former segment of the European–Iberian continental margin. They are juxtaposed today to units representing the deformation of the African and Adriatic plates margins as a product of Apenninic crustal shortening. A complex pattern of unconformities reveals a multi-stage tectonic evolution during the Early Jurassic, which affected the facies and geometries of siliciclastic and carbonate successions deposited in syn-and post-rift environments ranging from fluvial to deep marine. Late Sinemurian/Early Pliensbachian normal faulting resulted in exposure of the Hercynian basement at the sea-floor, which was onlapped by marine basin-fill units. Shallow-water carbonate aprons and reefs developed in response to the production of new accommodation space, fringing the newborn islands which represent structural highs made of Paleozoic crystalline and metamor-phic rock. Their drowning and fragmentation in the Toarcian led to the development of thin caps of Rosso Ammonitico facies. Coeval to these deposits, a thick (N 1 km) hemipelagic/siliciclastic succession was sedimented in neighboring hanging wall basins, which would ultimately merge with the structural high successions. Footwall blocks of the Early Jurassic rift, made of Paleozoic basement and basin-margin border faults with their onlapping basin-fill formations, are found today at the hanging wall of Miocene thrusts, overlying younger (Middle/Late Jurassic to Late Paleogene) folded basinal sediments. This paper makes use of selected case examples to describe the richly diverse set of features, ranging from paleontology to sedimentology, to structural geology, which are associated with the field identification of basin-margin unconformities. Our data provide key constraints for restoring the pre-orogenic architecture of a continental margin facing a branch of the Liguria–Piedmont ocean in the Western Tethys, and for estimating displacements and slip rates along synsedimentary faults.