The stratigraphic structure of the lunar regolith was essential for studying the formation and evolution of the lunar shallow layer within the lunar crust, which was constrained by previous lunar missions through spectral remote sensing, laboratory analyses, and in situ radar, such as the lunar penetrating radar on Chang'e missions. However, the stratigraphy of the vertical shallow 3–5 m layer remains unclear to date. In this work, we proposed a method to stratify the shallow lunar regolith (<inline-formula><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula>5 m) using the microwave radiometer (MRM) onboard China's Chang'e-2 (CE-2). The averaged subsurface rock abundance (RA) at depths (<inline-formula><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula>0.5–5 m) was extracted from CE-2 microwave brightness temperature at four channels: 3.0, 7.8, 19.35, and 37 GHz. Variations of RA with depth were estimated based on the differing penetration depths of the MRM. The near-surface regolith at the Chang'e-3 and Chang'e-4 landing sites is divided into three layers: layer I, strongly weathered regolith with RA <inline-formula><tex-math notation="LaTeX">$< $</tex-math></inline-formula> 0.20; layer II, weakly weathered ejecta with RA <inline-formula><tex-math notation="LaTeX">$>$</tex-math></inline-formula> 0.50; layer III, moderately weathered paleoregolith with RA between 0.20 and 0.50. We speculated that impact events during the late Copernican period (approximately 50 million years ago) created a crater (approximately 450 m diameter). The ejecta layer exhibits high RA detectable by 7.8 GHz but not by 19.35 GHz.
With ongoing exploration and development in the Baiyun Sag, its southwestern portion has emerged as a promising target for significant hydrocarbon discoveries. However, commercial discoveries have yet to be achieved due to limited reservoir areal extent and tight reservoir properties. To resolve reservoir architecture and quality, we integrate seismic and core data, building a depositional-diagenetic model of the Eocene Enping Formation in the block L13. The results show that the Enping braid deltas, sourced from the Shunhe Uplift, contain HST delta-front channels that constitute the principal reservoirs. Reservoirs comprise feldspathic litharenite and litharenite, with moderate-low porosity (6.6–21.1%) and low-ultralow permeability (0.02–21.30 mD). Pore systems are typified by tuffaceous dissolution pores and feldspar dissolution pores, with reservoir quality governed by the interplay of depositional and diagenetic processes. Coarser-grained textures in delta-front subaqueous distributary channels provide favorable reservoir frameworks, whereas compaction dominates porosity-permeability reduction. The key factor in enhancing reservoir properties is the formation of intergranular dissolution pores, which arise from the dissolution of tuffaceous material and feldspar by CO2-organic acid fluids generated during source rock evolution. This work establishes a depositional-diagenetic framework for reservoir prediction in the Enping Formation, offering critical insights for unlocking tight gas potential in the underexplored southwestern Baiyun Sag.
Philip I. Batanov, Ilyas F. Abkadyrov, Artem V. Degterev
et al.
The paper provides information on the objectives, methods, targets and some preliminary results of
the expeditionary work carried out within the framework of the RSF project No.21-17-00049 by the employees of
the Institute of Volcanology and Seismology of the FEB RAS, Institute of Marine Geology and Geophysics of the
FEB RAS, Pacific Geographical Institute of the FEB RAS and Trofimuk Institute of Petroleum-Gas Geology and
Geophysics of the SB RAS in 2022 and 2023. The main objectives of the expedition were geological volcanological, hydrogeological, geophysical, tephrochronological, and paleoseismological studies. In
accordance with the set objectives, field teams were formed, which began work in February 2022. On the basis
of the data obtained during the expedition, previously unknown hydrothermal manifestations and seismic events
on Iturup Island were identified. A number of geophysical and paleomagnetic surveys were carried out.
Catastrophic landslides occur frequently in Guizhou Province, China, and the landslides in this area have special geomorphological, geological, and anthropogenic features. In order to detect and explore the distribution pattern and control factors of active landslides in Guizhou, firstly, a total of 693 active landslides throughout Guizhou Province were mapped based on the deformation rate, which was obtained by spatiotemporal filtering and Intermittent Small Baseline Subset (ISBAS) Interferometric Synthetic Aperture Radar (InSAR) techniques. Then, the relationships between the detected landslides and elevation, aspect, slope gradient, and stratigraphic lithology were analysed. Moreover, it was found that the landslides were mainly concentrated in three stratigraphic combinations, that is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>f</mi><mo>~</mo><msub><mrow><mi>P</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>l</mi><mo>−</mo><mi>d</mi></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>f</mi><mo>~</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>y</mi><mi>n</mi></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>g</mi><mo>~</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>y</mi><mi>n</mi></mrow></semantics></math></inline-formula>. Thereafter, the correlation coefficients between the landslide density and elevation and distance to the stratigraphic boundary were 0.54 and −0.19, indicating that the distribution of landslides was significantly controlled by the elevation and the boundary of specific stratigraphic combinations. Finally, we chose a typical landslide to explore how landslide development was controlled by the combined effects of elevation and stratigraphy by using ascending and descending InSAR results. We revealed that landslides occurred primarily in areas with a steep slope and a stratigraphy characterized by mudstone and sandstone.
Valeri Grigorov, Victoria Russeva, Nadezhda Atanassova
This study presents five graves discovered east of the Palace Centre in Pliska (fig. 1). They represent individual burials located in the inter-dwelling area (fig. 2). The graves’ contexts were studied interdisciplinarily. The archaeological study provided data on the stratigraphy of the graves and detailed documentation of the burial pits and skeletal remains. The anthropological study provided information about the sex, age and height of the buried individuals, also their anatomical and anthropological features, disease (pathologies), traumas and medical manipulations that left traces on the bone remains.
Stratigraphically, the graves date to the last phase of habitation of the medieval city (between the 30s/40s of the 11th c. and the 60s of the 11th c.). The newly studied graves can be placed in the context of the other intramural graves in the Inner City of Pliska, which makes it possible to clarify and summarize a wide range of issues related to the stratigraphy and chronology of the intramural graves and their connection with the demographic and ethnic cultural changes in the medieval city.
Gaudenyi Tivadar, Nenadić Draženko, Jovanović Mlađen
et al.
The geological analysis of artesian borehole material from Sombor, Subotica, and Zrenjanin, was in the first campaign of detailed stratigraphic studies of Vojvodina in 1892-1895. The results of Quaternary stratigraphy from Zrenjanin were published by HalaVaTS more than a decade later (1914). The significance of the Zrenjanin, Sombor, and Subotica artesian well profiles for more than a century is considered the representative local profiles for the Quaternary stratigraphy of Vojvodina recognized by Serbian (Yugoslavian) and Hungarian geologists. Significant changes were after the taxonomical revision of molluscan material and its stratigraphic context, which was done through the excellent work of Krolopp in the 1970-ies. Unfortunately, the mentioned changes were not applied in the studies during the geological surveying of former Yugoslavia. The developments in Quaternary geology, changes in the Quaternary chronostratigraphic scale, and the results shown by this paper enable the lower Pleistocene fluvial deposits to be defined as the Pleistocene Corbicula beds, the Viviparus boeckhi Horizon. The lower Pleistocene at Zrenjanin was documented from 234.54 to 58.36 m depth. The interval between 234.54 and 208.50 m comprises the Upper Paludina – Viviparus vucotinovici zone, while the Viviparus boeckhi Horizons were identified between 135.18 m and 58.36 m. The interval between 58.36 m and 37.75 m is defined as Pleistocene (lower- and Middle Pleistocene) based on sedimentological and the molluscan record. The interval from 37.75 m to 21.67 m depth was identified as Middle Pleistocene, according to its lithology and the paleontological material. The fluvial sediments’ 21.69 m and 7.31 m depths cannot be determined according to the faunistic data; we can only consider them as Pleistocene age. The Holocene sediment and soil horizons ascend to a 2.90 m depth.
<p>We present pre-stack depth-imaging results for a case study of 3D reflection
seismic exploration at the Blötberget iron oxide mining site belonging
to the Bergslagen mineral district in central Sweden. The goal of the study
is to directly image the ore-bearing horizons and to delineate their
possible depth extension below depths known from existing boreholes. For
this purpose, we applied a tailored pre-processing workflow and two
different seismic imaging approaches, Kirchhoff pre-stack depth migration
(KPSDM) and Fresnel volume migration (FVM). Both imaging techniques deliver
a well-resolved 3D image of the deposit and its host rock, where the FVM
image yields a significantly better image quality compared to the KPSDM
image. We were able to unravel distinct horizons, which are linked to known
mineralization and provide insights on their possible lateral and depth
extent. Comparison of the known mineralization with the final FVM reflection
volume suggests a good agreement of the position and the shape of the imaged
reflectors caused by the mineralization. Furthermore, the images show
additional reflectors below the mineralization and reflectors with opposite
dips. One of these reflectors is interpreted to be a fault intersecting the
mineralization, which can be traced to the surface and linked to a fault
trace in the geological map. The depth-imaging results can serve as the
basis for further investigations, drilling, and follow-up mine planning at
the Blötberget mining site..</p>
<p>In an effort to improve our understanding of the seismic
character of the crust beneath southeast Australia and how it relates to
the tectonic evolution of the region, we analyse teleseismic earthquakes
recorded by 24 temporary and 8 permanent broadband stations using the
receiver function method. Due to the proximity of the temporary stations to
Bass Strait, only 13 of these stations yielded usable receiver functions,
whereas seven permanent stations produced receiver functions for subsequent
analysis. Crustal thickness, bulk seismic velocity properties, and internal
crustal structure of the southern Tasmanides – an assemblage of Palaeozoic
accretionary orogens that occupy eastern Australia – are constrained by
<span class="inline-formula"><i>H</i></span>–<span class="inline-formula"><i>κ</i></span> stacking and receiver function inversion, which point to the following:
</p><ol><li>
<p id="d1e158">a <span class="inline-formula">∼</span> 39.0 km thick crust; an intermediate–high <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="bfd54d15381023f9a454fbbd52948b7b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00001.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00001.png"/></svg:svg></span></span> ratio
(<span class="inline-formula">∼</span> 1.70–1.76), relative to ak135; and a broad (<span class="inline-formula">></span> 10 km) crust–mantle transition beneath the Lachlan Fold Belt. These results are
interpreted to represent magmatic underplating of mafic materials at the
base of the crust.</p></li><li>
<p id="d1e201">a complex crustal structure beneath VanDieland, a
putative Precambrian continental fragment embedded in the southernmost
Tasmanides, that features strong variability in the crustal thickness (23–37 km) and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="87a30c690410d7a09a7056c68eebd7c3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00002.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00002.png"/></svg:svg></span></span> ratio (1.65–193), the latter of which likely represents
compositional variability and the presence of melt. The complex origins of
VanDieland, which comprises multiple continental ribbons, coupled with
recent failed rifting and intraplate volcanism, likely contributes to these
observations.</p></li><li>
<p id="d1e223">stations located in the East Tasmania Terrane and
eastern Bass Strait (ETT <span class="inline-formula">+</span> EB) collectively indicate a crust of uniform
thickness (31–32 km), which clearly distinguishes it from VanDieland to the
west.</p></li></ol><p>
Moho depths are also compared with the continent-wide AusMoho model in
southeast Australia and are shown to be largely consistent, except in
regions where AusMoho has few constraints (e.g. Flinders Island). A joint
interpretation of the new results with ambient noise, teleseismic tomography,
and teleseismic shear wave splitting anisotropy helps provide new insight
into the way that the crust has been shaped by recent events, including
failed rifting during the break-up of Australia and Antarctica and recent
intraplate volcanism.</p>
Réka Orsolya Tapody, Pál Sümegi, Dávid Molnár
et al.
This paper presents the results of comparative sedimentological and geochemical analysis of the mire at Sânpaul, Round Lake (Kerek-tó). The palaeoecological site is situated in the western foothill area of the Eastern Carpathians in Romania. The primary objective of this study was to analyse the accumulation of major and trace elements in a 7500 year-long peat and lake deposition. The concentrations of 13 elements were determined by using handheld XRF. This paper presents the results of a multidisciplinary study, for which the principal aims were to examine the long-term relationship between land degradation in the Homoród Hills using various palaeoecological techniques, primarily comparative geochemical analyses. The PCA of elemental concentrations suggests that Round Lake is mainly controlled by the input of inorganic mineral matter and the LOI550 of peat. However, some elements are influenced by biological processes of vegetation and groundwater. Geohistorical studies compared with vegetation changes and elemental distribution helped the detection of erosion phases in the level of 12 prehistoric cultures.
Helen Howard, Lloyd de Beer, David Saunders
et al.
Recent imaging, examination, and analysis of the few surviving fragments of wall painting from St Stephen’s Chapel have revealed new data relating to the original technique and aspects of workshop practice in the production of these important mid-fourteenth-century wall paintings. Infrared imaging of the paintings provides clear evidence for the presence of an under-drawing and of extensive modification of the design in situ at an advanced stage of the painting process. There are marked differences in the character of the under-drawing on the various fragments studied, which are likely to relate to different hands and may be indicative of workshop practice. In addition, the presence of an original varnish is strongly suggested, the red dyestuff employed for the red lake pigment has been identified, and the complexity of pigment mixtures and stratigraphy of the paint layers has also been elucidated. This information will be discussed in the context of the documentary sources and of analytical results from the investigation of contemporaneous polychromy.
Yu.I. Inozemtsev, O.O. Paryshev, L.V. Stupina
et al.
The article notes that during the Quaternary period there was at least 5—6 glaciations, which each time entailed a sharp change in the ecological and hydrological situation both in the Caspian Sea and in the Black Sea. The change in temperature and salinity of the waters was reflected both in the composition of the fauna and in the lithological composition of the deposited sediments. During the cooling period, the Black Sea and the Caspian Sea regressed, they were isolated from each other, as well as from the World Ocean due to the presence of the Bosphorus threshold up to a mark of –36…–37 m. During the period of global warming, the level of the World Ocean returned each time to approximately the present mark, which was also characteristic of the Black and Caspian Seas. The tendency of level fluctuations in the indicated basins was of the same type, but the rate of these fluctuations, especially at the transgression stage, had sharp differences. This is especially pronounced in the Caspian Sea, in which the level from the –13 m mark about 17 thousand years ago rose to zero, –2 m about 15,5 thousand years ago. The level of the World Ocean during this period of time rose only to the –90 m mark. The Black Sea was also in a transgressive state, but its level was determined by the height of the Bosphorus threshold. This follows from the fact that inland basins were much faster than the oceans in their filling rate. The nature of the mutual penetration of the Mediterranean and Caspian fauna into the Black Sea was determined by the state of overdeepening of the Manych Valley, the Kerch and Bosphorus Strait, which is confirmed by the presence of the Caspian fauna of the Chaudino type in the Sea of Marmara (Gallipoli), and the Mediterranean fauna (Cardium edule L.) in the East of Manych, the Northwest Caspian (ChaudoBaku time) and the Caspian Sea — In the Holocene.
The Eocene shallow marine deposits marking the first marine incursion in the Biga Peninsula (NW Turkey) after the collision of the Sakarya and Anatolide-Tauride plates were investigated based on paleontological, litho- and chrono-stratigraphic data. Larger Benthic Foraminifera (LBF) from patchily distributed outcrops were studied in order to i) revise the stratigraphy of Eocene shallow marine units, and ii) establish a modern biostratigraphic setting and a correlation scheme. The Şevketiye Formation (Fm.) is herein defined as a predominantly shallow marine clastic deposit with subordinate carbonates overlying the Çamlıca metamorphic rocks, and passing laterally to the Soğucak Fm., a carbonate unit that is widely represented in the Thrace Basin. The record of alveolinids, primitive developmental stages of heterosteginids, and orthophragminids in the Şevketiye Fm. suggests that this formation is part of the Shallow Benthic Zones (SBZ) 16?/17 (Late Lutetian?/Early Bartonian), SBZ17?/18 and SBZ19A (Early Bartonian/earliest Priabonian). The Soğucak Fm., which overlies the Eocene volcanics, on the other hand, yielded advanced developmental stages of heterosteginids, Spiroclypeus sp. and Nummulites fabianii lineages, implying a younger marine incursion during the Late Eocene (earliest Priabonian; SBZ19A). A drastic shift in the depositional regime is marked amid Priabonian by the deposition of deep-marine clastics and volcanoclastics of the Ceylan Fm. In conclusion, the Eocene Sea transgressed first Gökçeada (in the Aegean Sea) during the Late Lutetian, then reached the Biga and Gelibolu peninsulas in the Bartonian, and finally led to the widespread deposition of carbonate and siliciclastic rocks in the Biga Peninsula and the Thrace Basin during the Late Bartonian and Priabonian.
The online collection of earthquake reports in Europe is strongly fragmented
across numerous seismological agencies. This paper demonstrates how
collecting and merging online institutional macroseismic data strongly
improves the density of observations and the quality of intensity shaking
maps. Instead of using ZIP code Community Internet Intensity Maps, we geocode
individual response addresses for location improvement, assign intensities to
grouped answers within 100 km<sup>2</sup> grid cells, and generate intensity
attenuation relations from the grid cell intensities. Grid cell intensity
maps are less subjective and illustrate a more homogeneous intensity
distribution than communal ZIP code intensity maps. Using grid cells for
ground motion analysis offers an advanced method for exchanging transfrontier
equal-area intensity data without sharing any personal information. The
applicability of the method is demonstrated on the felt responses of two
clearly felt earthquakes: the 8 September 2011 <i>M</i><sub>L</sub> 4.3
(<i>M</i><sub>w</sub> 3.7) Goch (Germany) and the 22 May 2015 <i>M</i><sub>L</sub> 4.2
(<i>M</i><sub>w</sub> 3.7) Ramsgate (UK) earthquakes. Both events resulted in a
non-circular distribution of intensities which is not explained by
geometrical amplitude attenuation alone but illustrates an important low-pass
filtering due to the sedimentary cover above the Anglo-Brabant Massif and in the
Lower Rhine Graben. Our study illustrates the effect of increasing bedrock
depth on intensity attenuation and the importance of the WNW–ESE Caledonian
structural axis of the Anglo-Brabant Massif for seismic wave propagation.
Seismic waves are less attenuated – high <i>Q</i> – along the strike of a
tectonic structure but are more strongly attenuated – low <i>Q</i> –
perpendicular to this structure, particularly when they cross rheologically
different seismotectonic units separated by crustal-rooted faults.
Isotope stratigraphy has become the method of choice for investigating both
past ocean temperatures and global ice volume. Lisiecki and Raymo (2005)
published a stacked record of 57 globally distributed benthic <i>δ</i><sup>18</sup>O
records versus age (LR04 stack). In this study LR04 is compared to
high-resolution records collected at all of the sites drilled during ODP Leg
154 on the Ceara Rise, in the western equatorial Atlantic Ocean. Newly
developed software is used to check data splices of the Ceara Rise sites and
better align out-of-splice data with in-splice data. Core images recovered
from core table photos are depth and age scaled and greatly assist in the
data analysis. The entire splices of ODP sites 925, 926, 927, 928 and 929
were reviewed. Most changes were minor although several were large enough to
affect age models based on orbital tuning. A Ceara Rise composite record of
benthic <i>δ</i><sup>18</sup>O is out of sync with LR04 between 1.80 and 1.90 Ma,
where LR04 exhibits two maxima but Ceara Rise data contain only one. The
interval between 4.0 and 4.5 Ma in the Ceara Rise compilation is decidedly
different from LR04, reflecting both the low amplitude of the signal over
this interval and the limited amount of data available for the LR04 stack. A
regional difference in benthic <i>δ</i><sup>18</sup>O of 0.2 ‰ relative to
LR04 was found. Independent tuning of Site 926 images and physical property
data to the Laskar et al. (2004) orbital solution and integration of
available benthic stable isotope data from the Ceara Rise provides a new
regional reference section for the equatorial Atlantic covering the last
5 million years.
There are few cases of open caves that have been reliably dated to ages greater than 65 Ma. This does not mean that such caves are extremely rare, rather it is difficult to reliably establish that a cave, or palaeokarst related to a cave, is this old. Relative dating methods such as: - regional stratigraphic, lithostratigraphic, biostratigraphic, relative climatic, relative isotopic, morphostratigraphic, and regional geomorphic are very useful. They suffer however from significant difficulties, and their results lack the impact of a crisp numerical date. While many of the methods used to date younger caves will not work over the required age range, some isotopic methods and palaeomagnetic methods have been applied with varying degrees of success. While finding something to date and having it dated is difficult enough, producing the date is rarely the end of the story. The difficult issue is not the date or relative correlation itself, but what the date or correlation means. Demonstrating that caves are ancient seems to rapidly become beset with the old adage that “extraordinary claims require extraordinary proof”. The presence of a well-dated or correlated sediment in a cave does not necessarily mean that the cave is that old or older. Perhaps the dated material was stored somewhere in the surrounding environment and deposited much more recently in the cave. A lava flow in a cave must be demonstrated conclusively to be a flow, not a dyke or a pile of weathered boulders washed into the cave. It must be conclusively shown that dated minerals were precipitated in the cave and not transported from elsewhere. There seems little doubt that in the future more ancient caves, or ancient sections of caves, will be identified and that as a result our perception of the age of caves in general will change.
R.A.L. Osborne: Datiranje starih jam in z njimi povezanega paleokrasa
Je le nekaj primerov odprtih jam, ki bi imele zanesljivo določeno starost nad 65 milijonov let. To ne pomeni, da so take jame izredno redke, ampak da je težko zanesljivo ugotoviti, da so oziroma paleokras, povezan z njimi, res tako stare. Relativne metode datiranja, kot so regionalno stratigrafsaka, litostratigrafska, biostratigrafska, relativno klimatološka, relativno izotopska, morfostratigrafska in regionalno geomorfološka, so zelo uporabne. Imajo pa pomembne pomanjkljivosti, saj njihovi izsledki ne temelje na jasnih številčnih podatkih. Medtem, ko marsikatera od metod, ki so uporabne za datiranje mlajših jam, ni uporabna za omenjeno starost, pa je bilo uporabljenih več izotopskih in paleomagnetnih metod z različnim uspehom. Težko je najti snov za datiranje in jo datirati, a sama starost še ni konec zgodbe. Težava ni z datiranjem ali s korelacijo, ampak v tem, kaj starost oziroma korelacija pomenita. Dokazovanje, da so jame stare, je hitro odpravljeno s pregovorom »Izredni izsledki zahtevajo izredne dokaze«. Dobro datirani ali korelirani sedimenti v jami še ne pomenijo, da je jama toliko stara ali starejša. Morda je bilo datirano gradivo odloženo nekje v okolici in šele mnogo kasneje preneseno v jamo. Lavin tok v jami mora biti neizpodbitno določen kot lavin tok, ne pa da je dyke ali balvani, prenešeni v jamo. Neizpodbitno mora biti dokazano, da so bili datirani minerali izločeni v jami in ne preneseni od nekod drugod. Nedvomno bo v bodoče spoznanih več starih jam ali njihovih delov in zaradi tega se bo tudi naše pojmovanje o starosti jam v celoti spremenilo.
Although the timing of the termination of the African Humid Period (AHP) is
now relatively well established, the modes and controlling factors of this
drying are still debated. Here, through a geomorphological approach, we
characterize the regression of Lake Turkana at the end of the AHP. We show
that lake level fall during this period was not continuous but rather
stepwise and consisted of five episodes of rapid lake level fall separated
by episodes marked by slower rates of lake level fall. Whereas the overall
regressive trend reflects a decrease in regional precipitations linked to
the gradual reduction in Northern Hemisphere summer insolation, itself
controlled by orbital precession, we focus discussion on the origin of the
five periods of accelerated lake level fall. We propose that these periods
are due to temporary reductions in rainfall across the Lake Turkana area
associated with repeated westward displacement of the Congo Air Boundary
(CAB) during solar activity minima.
The seismo-electromagnetic method (SEM) can be used for non-invasive
subsurface exploration. It shows interesting results for detecting
fluids such as water, oil, gas, CO<sub>2</sub>, or ice, and also help to better
characterise the subsurface in terms of porosity, permeability, and
fractures. However, the challenge of this method is the low level of
the induced signals. We first describe SEM's theoretical background,
and the role of some key parameters. We then detail recent studies
on SEM, through theoretical and numerical developments, and through
field and laboratory observations, to show that this method can
bring advantages compared to classical geophysical methods.