Quaternary Sequences Research Articles

Down-hole geophysical characterization of middle-upper Quaternary sequences in the Apennine Foredeep, Mirabello, Italy

The 2012 earthquakes sequence stroke a wide area of the alluvial plain in the Emilia-Romagna Region and triggered a new research interest on the role of the subsurface stratigraphic architecture and petrophysical property distribution in the modulation of the local seismic effects. Few direct shear wave velocity V_S data were however available below the depth of 50m. The only available V_S measurements were obtained from an anticline area, characterized by a reduced stratigraphic thickness and peculiar sedimentary facies, hardly representative of the majority of the alluvial plain subsurface. The study provides the first V_S profile available from middle-upper Quaternary successions deposited into a fast subsiding syncline area of the Apennine Foredeep Basin. The P-wave velocity V_P and the S-wave velocity V_S logs fill in the previous data gap on the geophysical parameters needed for the estimation of the local seismic response. Both V_P and V_S logs were continuously acquired to the depth of 265 m. The log records a velocity increase with depth, punctuated by sharp increases at some stratigraphic discordance surfaces. The value of 800 m/s that characterizes the “seismic bedrock”, as defined by the Italian building code [NTC 2008] was never reached at any depth. The investigated succession records a depositional evolution from deltaic-marine to alluvial plain conditions, punctuated by six glacio-eustatic depositional cycles, developed in Middle-Upper Quaternary times. The stratigraphic units described in the syncline log were correlated at a regional scale, with the thinner anticline succession of Mirandola. Correlatable units deposited into syncline and anticline areas reveal similar shear wave velocity values, supporting the regional extrapolation of the measured values.<br /><br /><br /><em></em>

The offshore Yangsan fault activity in the Quaternary, SE Korea: Analysis of high-resolution seismic profiles

The NNE-trending dextral Yangsan fault is a>190-km-long structure in the Korean Peninsula traced to the southeastern coast. The scarcity of Quaternary deposits onland precludes any detailed investigation of the Quaternary activity and structure of the Yangsan fault using seismic reflection profiling. We acquired offshore high-resolution seismic profiles to investigate the extension of the Yangsan fault and constrain its Quaternary activity using stratigraphic markers. The seismic profiles reveal a NNE-trending fault system consisting of a main fault and an array of subsidiary faults that displaced Quaternary sequences. Stratigraphic analysis of seismic profiles indicates that the offshore faults were activated repeatedly in the Quaternary. The up-to-the-east sense of throw on the main fault and plan-view pattern of the fault system are explained by dextral strike-slip faulting. The main fault, when projected toward the Korean Peninsula along its strike, aligns well with the Yangsan fault. We suggest that the offshore fault system is a continuation of the Yangsan fault and has spatial correlation with weak but ongoing seismicity.

Cenozoic lithogenesis in the Baikal rift zone

New data on the geological history and Cenozoic lithogenesis in depressions of the Baikal rift zone are considered with areas adjacent to Lake Baikal as example. In this region, rifting developed during the plain (Late Oligocene‒Early Pliocene) and orogenic (Late Pliocene‒Holocene) stages and was accompanied by the accumulation of plain coaliferous fan and orogenic molasses formations, respectively. The examination of Quaternary sequences in the Baikal region reveals that deposition and postsedimentary transformations of riftogenic sediments were intensely influenced by deep-seated water sources of the so far undivided stratal‒infiltration, elision, and exfiltration types, according to the classification in (Kislyakov and Shchetochkin, 2000). Deep processes in this region determined the elevated heat flow, volcanism, and extensive discharge of hydrothermal solutions and gas fluids. In our opinion, gaseous‒hydrothermal activity stimulated the formation of hydrothermal‒sedimentary rocks (dolomitic and calcitic travertines, geyserites, aluminosulfates), the accumulation of diatomaceous and carbonaceous oozes in Baikal, and the formation of a large methane gas hydrate deposit.

Deep electrical resistivity tomography along the tectonically active Middle Aterno Valley (2009 L'Aquila earthquake area, central Italy)

Three 2-D Deep Electrical Resistivity Tomography (ERT) transects, up to 6.36 km long, were obtained across the Paganica-San Demetrio Basin, bounded by the 2009 L'Aquila Mw 6.1 normal-faulting earthquake causative fault (central Italy). The investigations allowed defining for the first time the shallow subsurface basin structure. The resistivity images, and their geological interpretation, show a dissected Mesozoic-Tertiary substratum buried under continental infill of mainly Quaternary age due to the long-term activity of the Paganica-San Demetrio normal faults system (PSDFS), ruling the most recent deformational phase. Our results indicate that the basin bottom deepens up to 600 m moving to the south, with the continental infill largely exceeding the known thickness of the Quaternary sequence. The causes of this increasing thickness can be: (1) the onset of the continental deposition in the southern sector took place before the Quaternary, (2) there was an early stage of the basin development driven by different fault systems that produced a depocentre in the southern sector not related to the present-day basin shape, or (3) the fault system slip rate in the southern sector was faster than in the northern sector. We were able to gain sights into the long-term PSDFS behaviour and evolution, by comparing throw rates at different timescales and discriminating the splays that lead deformation. Some fault splays exhibit large cumulative throws (>300 m) in coincidence with large displacement of the continental deposits sequence (>100 m), thus testifying a general persistence in time of their activity as leading splays of the fault system. We evaluate the long-term (3–2.5 Myr) cumulative and Quaternary throw rates of most of the leading splays to be 0.08–0.17 mm yr−1, indicating a substantial stability of the faults activity. Among them, an individual leading fault splay extends from Paganica to San Demetrio ne’ Vestini as a result of a post-Early Pleistocene linkage of two smaller splays. This 15 km long fault splay can explain the Holocene surface ruptures observed to be larger than those occurred during the 2009 L'Aquila earthquake, such as revealed by palaeoseismological investigations. Finally, the architecture of the basin at depth suggests that the PSDFS can also rupture a longer structure at the surface, allowing earthquakes larger than M 6.5, besides rupturing only small sections, as it occurred in 2009.

On the pseudorandomness of quaternary sequences derived from sequences over $$\mathbb F_4$$ F 4

In analogy to the corresponding measures of pseudorandomness for quaternary sequences introduced by Mauduit and Sarkozy (for m-ary sequences) we introduce the well-distribution measure and correlation measure of order k for sequences over \(\mathbb F_4\). Using any fixed bijection from \(\mathbb F_4\) to the set of complex fourth roots of unity, we analyze the relation of these pseudorandomness measures for sequences over \(\mathbb F_4\) and for the corresponding quaternary sequences. More precisely, we show that they differ only by a multiplicative constant (depending only on k). We also apply the results for deriving new quaternary pseudorandom sequences from pseudorandom sequences over \(\mathbb F_4\) and vice versa.

Shallow groundwater investigation using time-domain electromagnetic (TEM) method at Itay El-Baroud, Nile Delta, Egypt

The Nile Delta is one of the oldest known ancient delta, largest and most important depositional complex in the Mediterranean sedimentary basin. Furthermore, it is a unique site in Egypt that is suitable for accumulation and preservation of the Quaternary sediments. In this work we applied time-domain electromagnetic (TEM) method to investigate the Quaternary sediments sequence as well as detecting the groundwater aquifer in the area of study.A suite of 232 TEM sounding at 43 stations were carried out using a “SIROTEM MK-3” time-domain electromagnetic system. A simple coincident loop configuration, in which the same loop transmits and receives signals, was employed with loop side length of 25m. The 1-D modeling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical data.Based on the interpretation of the acquired geophysical data, four geoelectric cross-sections were constructed. These sections show that the Upper Quaternary sequence consists of three geoelectric layers. The Holocene Nile mud is separated into two layers: the agricultural root zone (Layer 1) and thick water saturated mud (Layer 2). The Upper Pleistocene sandy aquifer (Layer 3) is very complicated non-linear boundary. This aquifer is the most important unit since it is considered as the main water bearing unit in the study area.

Comparison of Holocene temperature data (Boomplaas Cave) and oxygen isotope data (Cango Caves)

Boomplaas Cave is situated near the town of Oudtshoorn in the Western Cape Province, South Africa. It was excavated by Hilary Deacon in the 1970s, yielding not only Late Quaternary artefacts that were of archaeological importance but also fossils of rodents and insectivores (analysed by Margaret Avery) as well as bovids and equids (analysed by Richard Klein) that were important for the reconstruction of palaeoenvironments in the context of changes in climate within part of the Late Pleistocene (12 000-80 000 years BP) and Holocene (younger than 12 000 years BP). Also of palaeoclimatic importance is a stalagmite from the adjacent Cango Caves, analysed by John Vogel and Siep Talma. In 1992, Talma and Vogel used a transfer function to estimate Holocene temperatures from oxygen isotope data from the Cango speleothem. Their basic oxygen isotope data (Figure 1) can be compared to temperature estimates obtained from Thackeray's multivariate analysis of fossil rodents and insectivores represented in the late Quaternary sequence from Boomplaas Cave (Table 1). Here, for the first time, a comparison is made between the results obtained by Talma and Vogel with those obtained by Thackeray, both of which relate to temperature but use independent sources of data.

Debatable aspects of initial human colonization of Siberia and age of the Karama site in the Altai Mountains

Debatable aspects of age, stratigraphic position, and natural conditions of the oldest stratified Early Paleolithic Karama site in the Altai Mountains are critically revised. The extensive geological, stratigraphic, and paleontological data allow the sufficiently well-substantiated assumption that accumulation of the Karama Formation and existence of the Early Paleolithic Karama site correspond to a long period of climate warming in the Early Pleistocene correlated with the Tiglian of northwestern Europe lasting from 2.23 to 1.59 Ma. The age model proposed for the formation of the Quaternary sequence in the Anui River valley, which includes the artifact-containing deposits of the Karama site, seems to be the most probable one proceeding from interpretation of available data on the geological structure, stratigraphy, paleomagnetism, and paleontological and lithological properties of Upper Cenozoic sequences observable both in the Anui River valley and in Siberian areas adjacent to the Altai mountainous region.

On $\omega$-cyclic-conjugated-perfect quaternary GDJ sequences

A sequence is called perfect if its autocorrelation function is a delta function. In this paper, we give a new definition of autocorrelation function: $\omega$-cyclic-conjugated autocorrelation. As a result, we present several classes of $\omega$-cyclic-conjugated-perfect quaternary Golay sequences, where $\omega=\pm 1$. We also considered such perfect property for $4^q$-QAM Golay sequences, $q\ge 2$ being an integer.

Linear complexity and trace representation of quaternary sequences over ℤ 4 $\mathbb {Z}_{4}$ based on generalized cyclotomic classes modulo pq

We define a family of quaternary sequences over the residue class ring modulo $4$ of length $pq$, a product of two distinct odd primes, using the generalized cyclotomic classes modulo $pq$ and calculate the discrete Fourier transform (DFT) of the sequences. The DFT helps us to determine the exact values of linear complexity and the trace representation of the sequences.

Complexity of diatom response to Lateglacial and Holocene climate and environmental change in ancient, deep and oligotrophic Lake Ohrid (Macedonia and Albania)

Abstract. Lake Ohrid (Macedonia and Albania) is a rare example of a deep, ancient Mediterranean lake and is a key site for palaeoclimate research in the northeastern Mediterranean region. This study conducts the analysis of diatoms as a proxy for Lateglacial and Holocene climate and environmental change in Lake Ohrid at a higher resolution than in previous studies. While Lake Ohrid has the potential to be sensitive to water temperature change, the data demonstrate a highly complex diatom response, probably comprising a direct response to temperature-induced lake productivity in some phases and an indirect response to temperature-related lake stratification or mixing and epilimnetic nutrient availability in others. The data also demonstrate the possible influence of physical limnological (e.g. the influence of wind stress on stratification or mixing) and chemical processes (e.g. the influence of catchment dynamics on nutrient input) in mediating the complex response of diatoms. During the Lateglacial (ca. 12 300–11 800 cal yr BP), the low-diversity dominance of hypolimnetic Cyclotella fottii indicates low lake productivity, linked to low water temperature. Although the subsequent slight increase in small, epilimnetic C. minuscula during the earliest Holocene (ca. 11 800–10 600 cal yr BP) suggests climate warming and enhanced stratification, diatom concentration remains as low as during the Lateglacial, suggesting that water temperature increase was muted across this major transition. The early Holocene (ca. 10 600–8200 cal yr BP) is characterised by a sustained increase in epilimnetic taxa, with mesotrophic C. ocellata indicating high water-temperature-induced productivity between ca. 10 600–10 200 cal yr BP and between ca. 9500–8200 cal yr BP and with C. minuscula in response to low nutrient availability in the epilimnion between ca. 10 200–9500 cal yr BP. During the middle Holocene (ca. 8200–2600 cal yr BP), when sedimentological and geochemical proxies provide evidence for maximum Holocene water temperature, anomalously low C. ocellata abundance is probably a response to epilimnetic nutrient limitation, almost mimicking the Lateglacial flora apart from the occurrence of mesotrophic Stephanodiscus transylvanicus in the hypolimnion. During the late Holocene (ca. 2600 cal yr BP–present), high abundance and fluctuating composition of epilimnetic taxa are probably a response more to enhanced anthropogenic nutrient input, particularly nitrogen enrichment, than to climate. Overall, the data indicate that previous assumptions concerning the linearity of diatom response in this deep, ancient lake are invalid, and multi-proxy analysis is essential to improve understanding of palaeolimnological dynamics in future research on the long, Quaternary sequence.

Linear complexity of generalised cyclotomic quaternary sequences of length 2 p m +1 q n +1

Sequences with high linear complexity play a fundamental part in cryptography. In this study, the authors construct general forms of Whiteman's generalised cyclotomic quaternary sequences with period 2p m+1 q n+1 of order two over 𝔽4 and give the linear complexity of the proposed sequences. The conclusions reveal that such sequences have good balance property and high linear complexity.

Identification of a late Quaternary alluvial–aeolian sedimentary sequence in the Sichuan Basin, China

The late Quaternary sedimentary sequence in the northwestern part of the Sichuan Basin consists of five lithological units and with increasing depth include the: Chengdu Clay; Brown Clay; Red Clay; Sandy Silt; and basal Muddy Gravel. The genesis, provenance and age of the sediments, as well as the possible presence of hiatuses within this sequence are debated. Measurements of grain-size, magnetic susceptibility, quartz content, quartz δ18O values, element composition, and Sr–Nd isotopic concentrations of samples from a typical sedimentary sequence in the area provides new insights into the genesis and history of the sequence. The new data confirm that the sediments in study site are alluvial–aeolian in origin, with basal alluvial deposits overlain by aeolian deposits. Like the uppermost Chengdu Clay, the underlying Brown Clay and Red Clay are aeolian in origin. In contrast, the Silty Sand, like the basal Muddy Gravel, is an alluvial deposit and not an aeolian deposit as previously thought. Moreover, the succession of the aeolian deposits very likely contains two significant sedimentary hiatuses. Sedimentological analysis demonstrates that the source materials for the aeolian deposits in the northwestern part of the Sichuan Basin and those on the eastern Tibetan Plateau are different. Furthermore, the loess deposits on the eastern Tibetan Plateau are derived from heterogeneous local sources.

New Middle Pleistocene records from the North-East foothills of Carpathian Mountains

Two kinds of paleogeographic records from the Middle Pleistocene were recently first discovered in the Bukovinian foothills of the Carpathian Mountains, not far downstream from the confluence of the Prut and Cheremosh Rivers. The area of investigation is associated with the lower Brusnytsia River, the right tributary of the Prut River (fig. 1). Due to the active tectonic uplift, wide spread of dispersal Neogenic and Quaternary sediments, and comparatively wet climate, the whole area of the Prut and Siret rivers’ interfluve is strongly damaged by landslides. Therefore it is quit problematic to find undisturbed Quaternary river terrace sequences in the area. Generally, the territory is characterized by the lack of Quaternary records at all. Only few Late Paleolithic sites without geological sequence were known few kilometers downstream the Prut R. Moreover it was important to look for the evidence of the Middle Pleistocene there

Marine tephra in the Japan Sea sediments as a tool for paleoceanography and paleoclimatology

Tephra is a product of large and explosive volcanic events and can travel thousands of kilometers before deposition. Consequently, tephra deposits are common in terrestrial, lacustrine, marine, and glacial environments. Because tephra deposition is a geologically synchronous event, tephras constitute important isochrones in the Quaternary sequence, not only in Japan but also throughout the northwest Pacific and its marginal seas. As a result, establishing the chronostratigraphic order of tephra deposits is an effective tool for assessing local and regional stratigraphies and for correlating events among sites. For example, tephrostratigraphy can provide precise chronological constraints for other stratigraphic data, such as magneto- and biostratigraphic data. Spatiotemporal variability in the occurrence and geochemistry of tephras can also be used to trace the magmatic evolution of island arcs and their relationships to regional tectonics. In a paleoclimatic context, tephra deposits allow the correlation of past climate events among terrestrial, lacustrine, and marine environments. Tephrochronology is also a fundamental element used in reconstructing the marine reservoir effect, where the ages of tephra in marine and terrestrial settings are compared. Therefore, tephra is a valuable tool not only in stratigraphy, chronology, and volcanology but also in paleoceanography and paleoclimatology.

Large low probability of intercept properties of the quaternary sequence with optimal correlation property constructed by legendre sequences

In this paper, we consider the Low Probability of Intercept(LPI) property of the quaternary sequence proposed by Kim, Jang, Kim, and No. We derive the LPI property of the sequence by calculating the triple autocorrelation bound of the sequence. The derived bound is approximately twice square root of the period of sequence that is similar to the triple correlation property of binary Legendre sequence.

Quaternary marine transgressions in eastern China

Based on the data from 117holes (9151 samples) and the research on ecology and palaeoecology of Foraminifera combined with that on Ostracoda, diatoms, pollen and spores, eight marine transgressions have been recognized in the great plain regions through the Quaternary sequences and two marine transgressions have been found since the Late Pleistocene in the coastal plain (bedrock coast) areas. In the North China Plain, these are in ascending order: the Bohai transgression in the Early Pleistocene, the Haixing and Huanghua transgressions in the Middle Pleistocene, the Baiyangdian and Cangzhou transgressions in the Late Pleistocene, and the Tianjin transgression in the Holocene. In the Yangtze River Delta region the Rugao and Zhoupu transgressions occurred in the Early Pleistocene, the Shanghai, Jiading, and Wangdian transgressions in the Middle Pleistocene, the Jiangyin and Ge Hu transgressions in the Late Pleistocene, and the Zhenjiang transgression in the Holocene. In the coastal plain (bedrock coast) areas of North China, the Cangzhou transgression was recorded in the Late Pleistocene and the Tianjin transgression in the Holocene, whereas in South China the Fuzhou transgression took place in the Late Pleistocene and the Changle transgression in the Holocene. The transgressions correspond to warm periods and regressions to cold periods. The younger transgressions were not only of shorter duration, but also of larger magnitude. These findings point to the existence of four flood event strata since the Middle Pleistocene: two in the late Middle Pleistocene and another two in the Late Pleistocene.

New constructions of quaternary low correlation zone sequence sets

Sequence sets with low correlation have very important applications in modern communication systems. As in quasi-synchronous code-division multiple access (QS-CDMA) system, sequence sets with low correlation zone (LCZ) perform better than other well-known sequence sets. Furthermore, binary or quaternary sequence sets are preferred because of their easy implementation. In this paper, based on the inverse Gray mapping and special binary sequence pairs, new quaternary LCZ sequence sets were constructed. In the LCZ, the maximum of the nontrivial autocorrelation and crosscorrelation values is 1 which show that the QS-CDMA system used the new sequences sets can control the interference in a very low level.

The Quaternary succession of the Bulè and Alpetto valleys (Monviso Massif, Piedmont) as a possible supply for prehistoric jade axes raw material

This contribution presents a geological mapping of the Quaternary succession of the Bule and low Alpetto tributary valleys (Po Valley, Piedmont), together with preliminary data on its petrography. The investigated area, covering an altitude range between 3015 and 1485 m a.s.l., is located in the Monviso Massif Ophiolite Complex, at the contact with marble and calcschist of the Dora-Maira Massif cover. The Quaternary sequence mainly consists of glacial, outwash, debris and landslide deposits, with local torrential/avalanche and colluvial bodies. The investigation on the petrographic composition of these sediments has allowed to recognize the occasional occurrence of jadeitite boulders, likely exploited during the Neolithic period for axe head production. Four possible jadeitite blocks have been found; one of them is described here for the first time, sizing up to 1 m3. In detail, one of the finds is a Neolithic site of jade polishing in the high Bule Valley that was referred to the middle of V millennium BC (Allisio, La Preistoria e l’alta Valle Po, Lar Editore, Perosa Argentina, 2012). The jadeitite blocks have been found in the debris (site A), landslide (site B), glacial (site C) and outwash (site d) sediments. The petrographic characterization of the new jadeitite samples might potentially shed light on the still controversial genesis of these peculiar rocks.

High-resolution OSL dating of a late Quaternary sequence from Xingkai Lake (NE Asia): Chronological challenge of the “MIS 3a Mega-paleolake” hypothesis in China

In this paper a combined OSL (49 samples) and 14C (14 samples) dating study was conducted on a sediment core from Xingkai Lake, NE Asia. A single-aliquot regenerative-dose protocol was used to determine the equivalent dose (De) of the extracted fine-grained (FG) quartz fraction; the suitability of the measurement procedure was confirmed by a set of luminescence tests (e.g., preheat plateau and dose recovery measurements). In addition, a post-IR infrared stimulated luminescence protocol at 290 °C (pIRIR290) was applied to the polymineral FG fraction of seven samples. Our results can be summarized as follows: (1) The uppermost sample was dated to ∼110 a, indicating that the OSL signal of FG quartz has been well bleached. This has been further confirmed by the consistency of OSL ages and pIRIR290 ages within <80 ka. The resulting OSL ages generally increased with depth, and the lowermost samples of core XK08 reached back to the last interglacial, although the pIRIR290 dating suggested that the quartz OSL ages likely begin to be underestimated beyond 80 ka; (2) The comparison of OSL and 14C ages suggested that the radiocarbon dating technique may significantly underestimate the age of sediments for samples older than 30 cal ka BP (corresponding to ∼25 14C ka BP), and thus it is necessary to pay attention when using such old 14C dates for paleoclimatic/archaeological interpretation; (3) This study challenges the radiocarbon-based chronology of the “MIS 3a Mega-paleolake” hypothesis, which had been reiterated for many years and extensively reported across northern and western China; and (4) The current high-resolution OSL dating record (one-age/5–10 cm) showed clear sedimentation rate changes down the core. The identified variations in the sedimentation processes at the orbital timescale may be related to regional/global climatic changes during the past 130 ka, and the high sedimentation rate during the last ∼0.4 ka has probably been caused by intensified human activities in the Xingkai Lake catchment.