StratFit: An Excel Workbook for correlation of multiple stratigraphic trends

Correlation of distinct stratigraphic sequences is often critical to characterize evolution of sedimentary basins, as well as for exploration of georesources and for paleoenvironmental and paleoclimatic reconstructions. Stratigraphic correlations are usually based on signal matching between two multiples proxies' records. Commonly, stratigraphers have to approach the correlation issue with time-consumig methods or specific software that may not be aesily accessible or may not allow a full and direct control of the adopted procedure. In this work, we propose a new simple tool, which consists of a single Microsoft Excel workbook (that we named StratFit) organized  in worksheets and allows an easy correlation of different stratigraphic curves and immediate visualization of the results. The correlation process is based on the forecast function and linear regression between subsequent couples of select  tie-points. The program is open source, user-friendly and llows a full control of the correlation process since all the computations are accessible for user's inspection and improvement. The StratFit workbook and the usermanual are freely distributed and can be downloaded as supplementary material

Multidisciplinary approach to constrain kinematics of fault zones at shallow depths: a case study from the Cameros–Demanda thrust (North Spain)

Determining transport direction in thrusts is one of the main issues to study deformation and to achieve reliable balanced cross-sections reconstruction of inverted basins and thrust systems. Anisotropy of Magnetic Susceptibility provides a tool to study deformation in fault rocks through the relationships between the magnetic susceptibility ellipsoid and deformational structures. The Cameros-Demanda Thrust (N Spain) shows a relatively simple history, with an average N-directed movement during the Cenozoic, and provides the possibility of determining the relationships between magnetic fabrics and transport directions in thrusts. The outcropping rocks are Mesozoic limestones in the hangingwall of the main thrust and Cenozoic conglomerates and Albian sandstones and coal in its footwall. Illite crystallinity and organic matter maturity indicate P-T conditions on the order of....The study of AMS in fault rocks (more than 400 samples distributed in 25 sites with fault gouge, breccia and microbreccia) in the Cameros thrust and its comparison with kinematic indicators (foliation, S/C structures and slickenside striations) indicates, in spite of the a priori simple relationships inferred from thrust geometry, a complex history of movements, changing from top-to-the-NW to top-to-the-NE along the history of Cenozoic thrusting. The transport direction is either oblique to the magnetic lineation and perpendicular to the strike of magnetic foliation, and can be checked with shear structures observed in thin sections and other kinematic indicators. The results obtained indicate that AMS can give clues about the transport direction in thrusts depending on the particular structures developed in each studied area

Sediment deposition in response to the glacial-interglacial changes on the continental slope of eastern Pennell-Iselin Bank in the Ross Sea, Antarctica

In order to understand the growth and retreat of glaciers in response to the glacial-interglacial changes, subglacial marine sedimentary sequences have been studied extensively in the continental shelf areas of the Ross Sea. The purpose is to comprehend the glaciomarine sedimentation change on the continental slope of eastern Pennell-Iselin Bank in the Ross Sea, using three gravity cores (C1, C2, C3) and three box cores (BC1, BC2, BC3) collected from sites (RS14-1, 2, 3), respectively, across the continental slope to the eastern side of the Pennell-Iselin Bank during XXIX° (2014) PNRA expedition (Rosslope Ⅱ project). Several sedimentological (grain size, magnetic susceptibility), elemental (XRF), geochemical (biogenic opal, total organic carbon, total nitrogen, C/N ratios, CaCO3), and isotopic (δ13C and δ15N of organic matter) parameters were measured along sediment cores with AMS 14C dating of bulk sediments. Core-sediments consist mostly of hemipelagic sandy clay or silty clay with scattered IRDs (Ice-Rafted Debris). A comparison of sediment properties between box cores and the top of gravity cores reveals that the loss of sediment during sampling is trivial. Sediment colors of gravity cores alternate between brown and gray downward. Based on the variation patterns of sediment properties, sediment lithology was divided into different units (A and B), and subunits (B1 and B2). AMS 14C dates and sediment properties assign Unit A, Unit B1, and Unit B2 to interglacial, deglacial, and glacial conditions, respectively. Unit A represents the Holocene and interglacial sediments deposited mainly by the suspension settling of biogenic particles with IRDs in the open marine condition. Unit B1 reflects the deglacial sediments with an increase in IRDs showing the transition of sediment properties from Unit B2 to Unit A by the retreat of subglacial ices. Unit B2 is characterized by different sediment properties, mainly supplied by the continuously lateral melt-water plume or distal part of debris flow originating from the front of grounding floes in the subglacial continental shelf under the ice shelf during the glacial period. Thus, Unit B contains mostly reworked and eroded sediments from the continental shelf with scattered IRDs. The influence of subglacial continental shelf sedimentation in terms of melt-water transport and/or distal stage of debris flow was limited as far as to the middle slope areas (Site 2) during the deglacial and glacial periods. The deeper Site 1 remains in seasonally open marine conditions during the glacial period, due to the peaks of biogenic opal and TOC contents. Keywords: sediment property, subglacial activity, continental slope, Ross Se

Geological map of the Tocomar Basin (Puna Plateau, NW Argentina): Implication for the geothermal system investigation

This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau regionFil: Filipovich, Ruben Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Baez, Walter Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Groppelli, Gianluca. CNR Istituto di Geologia Ambientale e Geoingegneria; ItaliaFil: Ahumada, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Aldega, Luca. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Berardi, Gabriele. Università Roma Tre III; ItaliaFil: Bigi, Sabina. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Caricchi. Chiara. Istituto Nazionale di Geofisica e Vulcanologia; ItaliaFil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Corrado, Sveva. Università Roma Tre III; ItaliaFil: De Astis, Gianfilippo. Istituto Nazionale di Geofisica e Vulcanologia; ItaliaFil: De Benedetti, Arnaldo Angelo. Università Roma Tre III; ItaliaFil: Invernizzi, Chiara. Universita Degli Di Camerino; ItaliaFil: Norini, Gianluca. CNR Istituto di Geologia Ambientale e Geoingegneria; ItaliaFil: Soligo, Michele. Università Roma Tre III; ItaliaFil: Taviani, Sara. University of Milano-Bicocca; ItaliaFil: Viramonte, Jose German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Giordano, Guido. CNR Istituto di Geologia Ambientale e Geoingegneria; Italia. Università Roma Tre III; Itali

Cenozoic geometric and kinematic evolution of the tuscan-umbrian tectono-stratigraphic units (northern Apennines) : paleothermometric and paleomagnetic constraints

In the past decades, paleothermal, thermochronological and paleomagnetic methodologies have been widely adopted for the reconstruction of orogenic belts evolution. Paleothermal and thermochronological analyses have allowed the reconstruction of the vertical paths (burial and exhumation path) of the sedimentary successions involved in the orogenic belts, providing thermal and time constraints on their evolution. Besides, paleomagnetic analysis are an excellent tool to assess kinematic models of curved orogenic systems because of its great potential to quantify vertical axis rotations. In this framework, a multidisciplinary approach was adopted in this thesis in order to understand the geometric and kinematic evolution of the Tuscan-Umbria-Marche Domain, in the inner portion of the Northern Apennines, during the Cenozoic time. In this sector of the Apennines, some issues on the deformation history are still unexplored. By integrating paleothermal, thermochronological and paleomagnetic results, it was possible to provide new data and constraints to reconstruct the tectonic evolution of this portion of the Apennine chain. Two key areas of Northern Apennines have been investigated. An inner sector, from the Trasimeno Lake to the south to the Garfagnana area to the north, where sedimentary succession of the Tuscan Domain units were analysed. An outer sector, in the Umbria- Marche-domain, where the analyses were concentrated in the area affected by the low angle normal faults Altotiberina system, from Massicci Perugini to east of the Gubbio fault. In chapter 1, the aim of the thesis, the methodology and the main phases of the research are illustrated. The methodological approach is based on the integration of common methods used in basin analysis, such as thermal analysis (organic matter optical analysis -vitrinite reflectance: Ro%, clay mineralogy by means of X-ray analyses) and thermochronological analyses (dating by fission track and (U-Th)/He in apatite). The optical studies of organic matter and X-ray diffraction analysis allowed defining the thermal maturity level reached by sedimentary succession. The thermochronological data define the age and rates of the exhumation. Paleothermal and thermochronological data were used to calibrate 1D thermo-structural models used to reconstruct the burial history and quantify the tectono-stratigraphic loads now removed. The paleomagnetic analyses were conducted in order to reconstruct the rotational history of the internal part of Northern Apennines. Besides paleomagnetic analysis, magnetic mineralogy analysis was carried out in order to identify the carriers of the natural remnant magnetization. The anisotropy of magnetic susceptibility (AMS) analysis was also carried out in the analysed sediments. This method constitutes an unique tool in defining the deformation pattern in poorly deformed sedimentary sequences, whose tectonic setting can’t easily be defined using classical structural methods. Chapter 2 illustrates the paleothermal analyses carried out in the internal sector (Tuscan Domain). Results show two main maturity trends: one perpendicular and the other parallel to the strike of the chain. In the first case, the paleothermal indicators record a decrease in thermal maturity from inner to outer sectors of the chain. In detail, Ro% values of the internal sector range from 0.6 to 0.9% indicating early-mid mature stages of hydrocarbon generation. Moving toward the external areas of the fold-and-thrust belt, values range from 0.3% to 0.5% indicating an immature stage of hydrocarbon generation. These data are in agreement with those obtained by the semi-quantitative analysis of clay fraction which shows a decrease of illite content in mixed layers from 89% (maximum temperature of 120-130 °C) to 38% (temperature below 100 °C) from hinterland towards foreland. Following the method proposed by Hillier (1995), a low heating rate, typical of foredeep basins, was obtained from the comparison between Ro% and I% in I/S mixed layers. A geothermal gradient of about 23 °C/Km is derived combining calculated heating and burial rates and used for thermal modelling. The second trend shows a thermal maturity increase, along the strike of the chain from the SW (Trasimeno lake area) toward the NW (Pratomagno area) where vitrinite reflectance maturity reaches values up to 0.95% and illite 87-89% in agreement with thermal maturity distribution derived from Ro% data. According to the performed one dimensional modelling, maximum burial and thermal maturity of the Tuscan Nappe succession decrease from the inner toward the outer sector with a corresponding reduction of the eroded thicknesses related to a reduction of the allocthonous (Ligurian Unit) which takes place from north to south along the chain, from hinterland towards foreland. Chapter 3 is focused in the area characterized by the low-angle Altoriberina normal fault system. Paleothermal (surface and well water) and thermochronological data were integrated, in order to develop an exhumation history model for this sector of the chain. The main evidence is an increase in the exhumation age from the innermost sector affected by the Altotiberina normal fault system (Massicci Perugini, 3 Ma) to the most external area affected by this system (to the east of the fault of Gubbio, 4.3 Ma). Significant novelty derives also from the rates of exhumation, suggesting quicker exhumation of Massicci Perugini (0.8 mm/yr) when compared to the area to the east of the Gubbio fault (0.5 mm/y). Therefore, these data suggest that most of the exhumation in the Massicci Perugini may be related to the recent activity of the normal faults and not only to the old compression phase and subsequent erosion. Thus the extensional activity of the Altotiberina Fault system may account for the younger exhumation age in the internal sector compared to the external one. Moreover the quicker erosion rate of about 0.8 mm/yr in the internal sector may be related to tectonic activity. In chapter 4, results obtained from paleomagnetic studies carried out in the Tuscan Domain, along the innermost arc, are shown. The rotational pattern recorded in Eocene- Oligocene sediments, shows a decrease of rotation values from lower (area of Trasimeno Lake) towards higher (Garfagnana area) latitude. In fact, mean rotations values recorded in the Trasimeno Lake area are 96° ± 25° counterclockwise, passing through 81° ± 35° counterclockwise for the Mt. Chianti area, up to 37° ± 16° counterclockwise in Garfagnana. These data do not fit into an oroclinal model, proposed for the external sector of the chain (Umbria-Marche domain). In this study I propose a new model that takes into account the contribution of the rotation of the Corsica-Sardinia block to the structural architecture of this sector of chain. This model predicts that the main tectonic phases of the internal sector of the chain occurred between Oligocene and early Miocene times, during the drift of the Corsica-Sardinia block. The Tuscan Domain units recorded rotation of the Corsica-Sardinia block during their incipient deformation. This block rotation occurred around a pole placed at 43.5° N and 9.5° E. At this time, the Northern Apennines and Corsica-Sardinia block were two different sectors of the upper plate of the Central Mediterranean subduction system, whereas the Umbria domain still represented the undeformed foreland. The contribution of the Corsica-Sardinia to the rotation of the Tuscan Domain depended on the position respect to the rotation pole. In fact, the amount of the Corsica-Sardinia block rotation is recorded in the southern areas (Lake Trasimeno) and tends to decrease at higher latitude (Mt. Chianti) until to the area at north of rotation pole where the contribution of Corsica Sardinia block rotation is not recorded (Garfagnana area ). In chapter 5, the AMS carried out on the same deposits analyzed for paleomagnetic reconstructions, are illustrated. AMS data show that the sediments are characterized by a dominant magnetic foliation parallel to the bedding plane, suggesting that the magnetic fabric is due to the compaction process during the diagenetic process that the sediments undergone. Moreover, a distinct magnetic lineation was observed, indicating an incipient deformation related to a compressional deformation, overprinted on to the original magnetic fabric. In most of the cases the lineation is parallel to the fold axes and thrust fronts, in agreement with previous results in the Umbria Marche domain. In chapter 6, a general discussion is developed and final remarks are illustrated

Reconstruction of maximum burial along the Northern Apennines thrust wedge (Italy) by indicators of thermal exposure and modeling

A new data set of temperature-dependent clay mineral parameters and vitrinite reflectance of the Tuscan successions in the Northern Apennines (Italy) displays decreasing levels of thermal maturity from hinterland to foreland, and abrupt changes parallel to the strike of the chain which are structurally controlled by northeast-southwest-trending faults (e.g., Marecchia valley lineament). To the southeast of the Marecchia valley lineament, paleothermal indicators show deep diagenetic conditions in the hinterland and early diagenetic conditions in the foreland (Ro% ranges from 0.80% to 0.30%; illite content in mixed-layer illite-smectite [I-S] from 86% to 38%). To the northwest of the Marecchia valley lineament, in the hinterland, Ro% is up to 0.95% and mixed-layer I-S have an illite content of ~87%-88%, both gradually decreasing toward the northeast (to Ro% of 0.33%, and illite in I-S of 50%). Thermal models allowed us to constrain the geometry of the Miocene thrust wedge with special regard to the original thickness and distribution of its allochthonous uppermost structural unit (Ligurian unit) across northeast-southwest-trending tectonic lineaments. The thickness of the Ligurian unit ranges from 1 to 1.5 km to the south of the Marecchia valley lineament, to 3 km to the north-northwest. This tectonic lineament affected wedge geometry, amounts of tectonic transport, and thickness of the uppermost structural unit, and, possibly, Neogene-Quaternary levels of exhumation

Distinct magnetic fabric in weakly deformed sediments from extensional basins and fold-and-thrust structures in the Northern Apennine orogenic belt (Italy)

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Thermal maturity of Silurian deposits in the Baltic Syneclise (on-shore Polish Baltic Basin): Contribution to unconventional resources assessment

Shale gas is envisaged to contribute in the next future to the European energy mix in the prospective of lowering CO2 emissions. Poland is by far one of the most perspective countries in Europe. In the "Golden Belt", potential productive levels are Early Paleozoic in age and the reliable assessment of their thermal maturity is crucial for evaluating hydrocarbon generation/expulsion scenarios. When exploring Lower Paleozoic targets that are devoid of vitrinite macerals, uncertainties in thermal maturity evaluation can occur according to commonly adopted parameters (e.g., vitrinite reflectance). These uncertainties can negatively influence targets assessment. We adopted a multi-method approach to assess thermal maturity of the Silurian sections encountered in three wells deep between 2.9 and 3.3 km, recently drilled in the Polish Baltic Basin. The methodological strategy consists of: (i) measurement of organoclasts (mainly graptolites) reflectance; (ii) FT-IR spectroscopy on bulk dispersed organic matter; (iii) X-ray diffraction on <2 μm grain-size fraction of sedimentary core samples. Organoclasts reflectance is between 0.6 and 1.4% indicating a large range of thermal maturity spanning from early to late mature stages of hydrocarbon generation. Mixed layers illite-smectite and FT-IR indexes (e.g. CH2/CH3, A and C) allowed us to improve the definition of thermal maturity of Lower Paleozoic rocks (Roeq between 0.8 and 1.1%). This original dataset indicates lower levels of thermal maturity than those predicted in pre-existing thermal maturity maps, suggesting that the Silurian sections experienced thermal maturity conditions equivalent to the oil window more than the gas window

Reconstruction of the Virtual Geomagnetic Pole (VGP) path at high latitude for the last 22 kyr: The role of radial field flux patches as VGP attractor

Reconstruction of geomagnetic field changes has a strong potential to complement geodynamo modeling and improve the understanding of Earth's core dynamics. Recent works based on geomagnetic measurements pointed out that over the last two decades the position of the north magnetic pole has been largely determined by the influence of two competing flux lobes under Canada and Siberia. In order to understand if the waxing and waning of magnetic flux lobes have driven the path of geomagnetic paleopoles in the past, we present an augmented and updated record of the chronology and paleosecular variation of geomagnetic field for the last 22 kyr derived from sedimentary cores collected along the north-western margin of Barents Sea and western margin of Spitsbergen (Arctic). The path of the virtual geomagnetic pole (VGP) has been reconstructed over this time period and compared with the maps of the radial component of the geomagnetic field at the core-mantle boundary, obtained from the most recent models. The VGP path includes centuries during which the VGP position is stable and centuries during which its motion accelerates. We recognize both clockwise and counterclockwise VGP paths, mostly developing inside the surface projection of the inner core tangent cylinder in the Arctic region. The VGP path seems to follow the appearance of Br patches of normal magnetic flux, especially those located under Siberia and Canada areas, but also those that may cause peculiar paleomagnetic features such as the Levantine Iron Age Anomaly