All ICDP Publications with Abstracts
From parent-sysfolder "Publications" + 2 folder-levels deep
2803.
Unlocking national treasures: the core scanning approach
Geological Society Special Publication,
527
(1)
77 – 94
2023
2802.
Underrepresentation of Local Researchers in Geophysical Studies at the Bosumtwi Impact Crater: Insights from A Systematic Review
Scientific African,
21
2023
2801.
The Upper-Lower Cretaceous boundary in the southern Songliao Basin: A case study of ICDP borehole SK-3; [松辽盆地南部上、下白垩统界线研究:以松辽盆地 国际大陆科学钻探松科3井为例]
Earth Science Frontiers,
30
(3)
425 – 440
2023
ISSN: 10052321
Publisher: Science Frontiers editorial department
Keywords:▾
Binary alloys; Boreholes; Deposits; Geochronology; Infill drilling; Isotopes; Lead alloys; Sedimentary rocks; Sedimentology; Stratigraphy; Zircon; Continental scientific drillings; Cretaceous denglouku - quantou formation; Denglouku formations; Drilling projects; International continental scientific drilling program borehole SK-3; Lower Cretaceous; Potential global boundary stratotype section and point golden spike in terrestrial stratum; Songliao basin; Upper and low cretaceous stratigraphic boundary; Upper Cretaceous; Deposition rates
Abstract: ▾ The internationally recognized absolute isotopic age of the Upper-Lower Cretaceous stratigraphic boundary is 100.5 Ma, and the Global Boundary Stratotype Section and Points (GSSP) for the boundary is placed in marine strata; however, there have been no reports of GSSP ("golden spikes") for terrestrial boundaries anywhere in the world. The terrestrial Upper-Lower Cretaceous stratigraphic boundary is of great value in understanding the evolution of paleogeography, paleoenvironment and paleoclimate on land under the greenhouse conditions in the Middle Cretaceous, and the ideal geological records for studying this boundary may be found in the Songliao Basin, northeastern China, where a complete set of Cretaceous continental strata are developed. Here, we investigated the rock types, lithologic sequence and sedimentary facies in the core section of International Continental Scientific Drilling Program (ICDP) borehole SK-3, southern Songliao Basin. Based on the core description, gray and gray-green rhyolitic lithic crystalline tuffite deposit is found in the coastal-shallow lacustrine sedimentary sequences of the upper part of the second member of the Quantou Formation at 1191. 6 m depth. The tuffite deposit, according to zircon U-Pb dating of its syndepositional magmatic components, has an zircon age of (96.8±2.9) Ma and belongs to the Middle-Cenomanian period. Combined with previous data, the deposition rate for the Quantou-Denglouku Formations in the study area is 90. 54-110 m/Ma, and we conclude accordingly that the Upper-Lower Cretaceous stratigraphic boundary is located in the middle of the first member of the Quantou Formation in borehole SK-3 (at 1526.6-1598. 6 m depth). Considering analytical errors in the age-dating results, the Upper-Lower Cretaceous stratigraphic boundary in borehole SK-3 is independently calculated to be between the middle of the second member of the Quantou Formation and the upper part of the fourth member of the Denglouku Formation (at 1279. 6-1917. 6 m depth). Other researchers have tentatively placed the boundary in the Denglouku Formation based on the chronological data of ICDP borehole SK-1 and SK-2, northern Songliao Basin. The continuous coring data reveal continuous fluvial-lacustrine sedimentary sequences in the Denglouku - Quantou Formations in borehole SK-3; while results of seismic horizon matching further suggest the Denglouku - Quantou Formations are widely developed across the Songliao Basin and sedimentary records of continuous deposition are widespread. Therefore, the Denglouku - Quantou Formations across the basin should provide the geological record of continuous deposition of the Upper-Lower Cretaceous stratigraphic boundary. And this paper provides the basic dataset and exploration direction to find the "golden spikes" for the Upper and Lower Cretaceous continental stratigraphic boundary in the Songliao Basin and adjacent areas. © 2023 Science Frontiers editorial department. All rights reserved.
2800.
Techanical properties and microscopic pore structure evolution mechanism of shale under deep well temperature and humidity environment (in Chinese with English abstract);[深井温湿环境下泥页岩力学特性及微观孔隙结构演化机制]
Exploration Engineering,
50
(S1)
126-134
2023
2799.
The response of borehole water levels in an ophiolitic, peridotite aquifer to atmospheric, solid Earth, and ocean tides
Journal of Hydrology X,
21
2023
2798.
The Possible Role of Anoxic Alkaline High Subcritical Water in the Formation of Ferric Minerals, Methane and Disordered Graphitic Carbon in a BARB3 Drilled Sample of the 3.4 Ga Buck Reef Chert
Origins of Life and Evolution of Biospheres,
53
(1-2)
1 – 41
2023
2797.
The origin of carbonates in impact melt-bearing breccias from Site M0077 at the Chicxulub impact structure, Mexico
Meteoritics and Planetary Science,
58
(6)
834 – 854
2023
Abstract: ▾ Carbonates from the impact melt-bearing breccia in the 2016 IODP/ICDP Expedition 364 drill core at Site M0077 were systematically documented and characterized petrographically and geochemically. Calcite, the only carbonate mineral present, is abundant throughout this deposit as five distinct varieties: (1) subangular carbonate clasts (Type A); (2) subround/irregular carbonate clasts with clay altered rims (Type B); (3) fine-crystalline matrix calcite (Type C); (4) void-filling sparry calcite (Type D); and (5) microcrystalline carbonate with flow textures (Type E). Quantitative geochemical analysis shows that calcite in all carbonate varieties are low in elemental impurities (<2.0 cumulative wt% on average); however, relative concentrations of MgO and MnO vary, which provides distinction between each variety: MgO is highest in calcite from Types A, B, and C carbonates (0.2–0.8 wt% on average); MnO is highest in calcite from Types B, C, and D carbonates (0.2–1.3 wt% on average); and calcite from Type E carbonate is most pure (<0.1 wt% on average MgO and MnO, cumulatively). Based on textural and geochemical variations between carbonate types, we interpret that some of the carbonate target rocks melted during impact and were immiscible within the silicate-dominated melt sheet prior to the resurgence of seawater. Type B clasts were formed by molten fuel–coolant interaction, as the incoming seawater eroded through the melt sheet and encountered carbonate melt (Type E). Post-impact meteoric-dominated hydrothermal activity produced the Mn-elevated calcite from Type C and D carbonates, and altered the Type B clasts to be elevated in Mn and host a clay-rich rim. © 2023 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society.
2796.
The geodynamic and limnological evolution of Balkan Lake Ohrid, possibly the oldest extant lake in Europe
Boreas,
52
(1)
1 – 26
2023
ISSN: 03009483
Publisher: John Wiley and Sons Inc
Keywords:▾
Balkan; Lake Ohrid; Turkmenistan; clast; displacement; geodynamics; lacustrine deposit; lake evolution; limnology; sedimentation; sedimentology
Abstract: ▾ Studies of the upper 447 m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm a−1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe’s presumed oldest extant freshwater lake. © 2022 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium.
2795.
The effect of temperature on the nonlinear elasticity of a fault rock in dynamic acoustoelastic testing (DAET) experiments
Geophysical Journal International,
235
(1)
554 – 565
2023
2794.
The Chicxulub impact structure reveals the first in-situ Jurassic magmatic intrusions of the Yucatán Peninsula, Mexico
Lithos,
436-437
2023
Abstract: ▾ Impact events that create complex craters excavate mid- to lower-crustal rocks, offering a unique perspective on the interior composition and internal dynamics of planetary bodies. On the Yucatán Peninsula, Mexico, the surface geology mainly consists of ∼3 km thick sedimentary rocks, with a lack of exposure of crystalline basement in many areas. Consequently, current understanding of the Yucatán subsurface is largely based on impact ejecta and drill cores recovered from the 180–200-km-diameter Chicxulub impact structure. In this study, we present the first apatite and titanite U–Pb ages for pre-impact dacitic, doleritic, and felsitic magmatic dikes preserved in Chicxulub's peak ring sampled during the 2016 IODP-ICDP Expedition 364. Dating yielded two age groups, with Carboniferous dacites (328–318 Ma) and a felsite (330± 9 Ma) overlapping in age with most of the granitoid basement sampled in the Expedition 364 drill core, as well as Jurassic dolerites (169–159 Ma) and a felsite (158 ± 19 Ma) that represent the first in situ sampling of Jurassic-age magmatic intrusions for the Yucatán Peninsula. Further investigation of the Nd, Sr, and Hf isotopic compositions of these pre-impact lithologies and impact melt rocks from the peak ring structure suggest that dolerites generally contributed up to ∼10 vol% of the Chicxulub impact melt rock sampled in the peak ring. This percentage implies that the dolerites comprised a large part of the Yucatán subsurface by volume, representing a hitherto unsampled pervasive Jurassic magmatic phase. We interpret this magmatic phase to be related to the opening of the Gulf of Mexico, representing the first physical sampling of lithologies associated with the southern extension of the opening of the Gulf of Mexico and likely constraining its onset to the Late Middle Jurassic. © 2022 Elsevier B.V.
2793.
The Brécy depocenter as part of a new northern Massif Central Carboniferous–Permian Basin (France)
Comptes Rendus - Geoscience,
355163 – 190
2023
2792.
Terrestrial dominance of organic carbon in an Early Cretaceous syn-rift lake and its correlation with depositional sequences and paleoclimate
Sedimentary Geology,
455
2023
Keywords:▾
China; Songliao Basin; Alumina; Aluminum oxide; Deposition; Kerogen; Lakes; Oil shale; Stratigraphy; Weathering; Carbon concentrations; Carbon source; Chemical weathering; Littorals; Lower Cretaceous; Mudstone; Organic carbon burial; Paleoclimates; Rift basin; Syn-rift; chemical weathering; climate variation; correlation; Cretaceous; depositional sequence; lacustrine deposit; lake evolution; mudstone; organic carbon; paleoclimate; sequence stratigraphy; Organic carbon
Abstract: ▾ Organic carbon (OC) burial in lakes has been identified as an efficient sink in the global carbon cycle. Abundant input of terrestrial-derived OC leads to high variability in OC origin and type, but its role in determining organic-rich sediments has been overlooked in prior studies. Here, we investigated the OC source and concentration of the Lower Cretaceous (Middle Aptian to Lower Albian) Shahezi Formation (Songliao Basin, NE Asia) to reveal the burial of terrestrial OC in relation to syn-rift lake evolution and paleoclimate change. The sequence stratigraphic framework of fan-deltaic and lacustrine successions was established by identifying depositional facies and sequence boundaries. The lacustrine-dominated interval was further subdivided into four facies associations (i.e., lake shore to littoral siltstones, shallow-littoral mudstones, sublittoral, and profundal) and a few cyclic, parasequence-order packages, using 90 m of continuous cores and high sampling frequency of RoqSCAN SEM-EDS. Multiple independent proxies (macerals identified using correlative light and electron microscopy, pyrolysis indices, Ro, TOC/TN, and δ13Corg) suggest that the organic fraction of the highly mature mudstones was predominantly contributed by terrestrial-derived OC (gas-prone type III/IV kerogen). A direct correlation between depositional facies, chemical weathering proxies (CIA, CIAcorr, and Ln(Al2O3/Na2O)), and OC burial (TOC and HI) has been established. A steep syn-rift slope, a warm–humid climate, abundant vegetation, and the subaqueous transport of OC-bearing sediments (e.g., massive mud-rich conglomerates and sand- to pebble-bearing mudstones), may have jointly promoted the high input of terrestrial OC. A comparison between two Lower Cretaceous terrestrial records from high and low paleolatitudes suggests that the shift from the syn-rift to post-rift phase was accompanied by an increase in TOC concentration and a change toward Type I kerogen of aquatic origin. The tectonically-controlled evolution of rift basins might be an important forcing function for the change of OC sources and concentrations, which is responsible for long-term OC burial in hinterland environments. © 2023
2791.
On the occurrence of rare nannoliths (calcareous nannofossils) in the Early Jurassic and their implications for the end-Triassic mass extinction
Papers in Palaeontology,
9
(2)
2023
2790.
An astronomical time scale for the Early Cretaceous continental strata in the Songliao Basin, Northeastern China (in Chinese with English abstract); [松辽盆地松科2井早白垩世沙河子组天文年代标尺]
Quaternary Sciences,
43
(6)
1573-1583
2023
2789.
Multiple S-isotopic evidence for seawater incursions during the deposition of the upper Cretaceous source rocks in the Songliao Basin, northeastern China
Chemical Geology,
642
2023
2788.
Constraints on the Nd-isotopic composition and nature of the last major influx of magma into the Bushveld Complex
Contributions to Mineralogy and Petrology,
178
(3)
14
2023
2787.
Drilling into a deep buried valley (ICDP DOVE): a 252\,m long sediment
succession from a glacial overdeepening in northwestern Switzerland
Scientific Drilling,
3227-42
2023
2786.
Development of the Chinese Continental Scientific Deep Drilling: Perspectives and Suggestions; [中国大陆科学深钻发展的若干思考与建议]
Geoscience,
37
(1)
1 – 14
2023
2785.
Development of Songliao Basin by Palaeo-Pacific slab rollback: Evidence from Early Cretaceous rhyolites in SK2 Borehole, NE China
Geological Journal,
58
(4)
1342 – 1365
2023
ISSN: 00721050
Publisher: John Wiley and Sons Ltd
DOI:10.1002/gj.4662
Keywords:▾
China; Songliao Basin; borehole; Cretaceous; geodynamics; hafnium; isotopic composition; neodymium isotope; petrogenesis; rhyolite; strontium isotope; uranium-lead dating; volcanic rock
Abstract: ▾ As the largest petroliferous basin in northeast (NE) China, Songliao Basin preserves continuous Cretaceous sedimentary-volcanic records, providing an excellent opportunity to recover the palaeo-environment. The Yingcheng Formation in the Songliao Basin contains ample gas reservoirs that attract widespread attention. Whereas the timing, petrogenesis and geodynamic mechanism of the volcanic rocks in the Yingcheng Formation are still controversial, which largely constrain our understanding of the formation and evolution of the Songliao Basin. Here, we present an integrated investigation of zircon U–Pb ages and Hf isotope, as well as whole-rock elements and Sr-Nd isotopes data for a suite of rhyolites of Yingcheng Formation from the SK2 Borehole of NE China. Zircon U–Pb age dating results of nine samples have yielded a concentrated age of ~110 Ma. These Yingcheng rhyolites are characterized by high SiO2 (66–78 wt%) and alkali (Na2O + K2O = 7.80–11.70 wt%) content, high 10000*Ga/Al (1.26–3.82, mostly >2.6) and FeOT/(FeOT + MgO) ratios (0.81–0.95), which show geochemical affinities with A-type rhyolites. They have relatively low Y/Nb (0.69–1.78, average 1.19) and Rb/Nb (1.58–6.52, average 4.34) ratios, suggesting that the Yingcheng volcanic samples belong to A1-type rhyolites which formed in an intraplate environment. These Yingcheng rhyolites show depleted Nd-Hf isotopic compositions (εNd(t) = 2.43–4.87 and zircon εHf(t) = 4.22–9.88) comparable with the Early Cretaceous A-type and I-type rhyolites in the Songliao Basin, suggesting that they were originated from a juvenile continental crust. They were most likely derived from the partial melting of anhydrous lower crust instead of differentiation of mantle-derived or mixing with alkaline basaltic magma, due to their low Mg# and absence of the coeval mafic rocks. Combined with the previous studies, A-type rhyolites in the Yingcheng Formation erupted lasting at least 10 Myr and were widely distributed in the rifts of the Songliao Basin. We propose that the Yingcheng rhyolites were most likely generated from the rollback of the Palaeo-Pacific Plate in the Early Cretaceous, thus highlighting the significance of the subduction of the Palaeo-Pacific Plate during the secular evolution of the Songliao Basin. © 2022 John Wiley & Sons Ltd.
2784.
Deciphering the tectonometamorphic history of subducted metapelites using quartz-in-garnet and Ti-in-quartz (QuiG-TiQ) geothermobarometry—A key for understanding burial in the Scandinavian Caledonides
Journal of Metamorphic Geology,
n/a
(n/a)
2023
ISSN: 1525-1314Keywords:▾
40Ar/39Ar dating, Scandinavian Caledonides, P–T–D–t evolution, quartz-in-garnet, Ti-in-quartz thermobarometry
Abstract: ▾ The Seve Nappe Complex is a subduction-related high-grade metamorphic unit that was emplaced onto the margin of Baltica during Caledonian orogenesis. In this paper, the tectonometamorphic evolution of the Lower Seve Nappe in the Scandinavian Caledonides was characterized with the help of the continuous Collisional Orogeny in the Scandinavian Caledonides (COSC-1) drill core, using a combination of various P–T estimation techniques based on garnet–quartz mineral pairs (quartz-in-garnet and Ti-in-quartz [QuiG–TiQ]), conventional thermobarometry and thermodynamic modelling of phase equilibria. This multi-method approach yields complementary results and delivers critical data to constrain a comprehensive pressure–temperature–deformation–time (P–T–D–t) evolutionary path for the metasedimentary rocks of the Lower Seve Nappe. In the garnetiferous metasedimentary rocks, quartz inclusions in garnet preserve the P–T conditions of three distinct garnet growth stages corresponding to three metamorphic stages Ms1 to Ms3, including prograde and peak metamorphic conditions. Ms1 and Ms2 stages were constrained via quartz inclusions in garnet core and mantle. They are relatively close in the P–T space and could be considered as one single continuous prograde event occurring at epidote–amphibolite facies conditions of 460–520°C and 0.6–0.85 GPa. The growth of the garnet outermost rim defines the Ms3 stage at amphibolite facies conditions of 590–610°C and 1.13–1.18 GPa and corresponds to the peak metamorphic conditions. The microstructural analysis shows that the finite ductile strain pattern of the Lower Seve Nappe results from the superposition of four deformation phases. The initial phase D1 is defined by the S1 foliation that is still preserved as a curved inclusion trail in the garnet core. The D2 phase initiated contemporaneously with garnet core growth and the development of muscovite–biotite–plagioclase S2 foliation. Garnet outermost rim growth marks the end of the prograde path and peak metamorphic conditions. This stage is overprinted by the D3 phase and Ms4 stage associated with the development of the main regional metamorphic and mylonitic fabric S3 associated with C′-type shear bands along the retrograde path. Ms4 stage, which was constrained using traditional thermobarometric techniques, corresponds to the chemical re-equilibration of the metasedimentary minerals and occurred under amphibolite facies conditions at 570–610°C and 0.78–1.00 GPa. The D3 phase is then generally weakly to strongly overprinted by later lower grade deformation D4 phase at greenschist facies conditions (Ms5). 40Ar/39Ar ages of syn-kinematic white mica and biotite indicate that the final stage of the thrusting of the Lower Seve Nappe and thus the timing of its emplacement onto the Offerdal Nappe occurred at c. 423 Ma. Collectively, these results are consistent with previous estimates of the timing and conditions of metamorphism derived from the Lower Seve Nappe especially in west-central Jämtland. However, application of QuiG–TiQ thermobarometry demonstrated that quartz inclusions in garnet can preserve different aspects of garnet growth, which are not accessible by traditional methods especially in complex terranes, and therefore provided new significant insights into the Lower Seve prograde evolution.
2783.
Cross-Property Relationship Between Electrical Resistivity and Elastic
Wave Velocity of Crustal Rocks From the Oman Drilling Project Hole GT3A:
Implications for in Situ Geophysical Properties of Oceanic Crust
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,
128
(6)
2023
Keywords:▾
electrical resistivity; elastic wave velocity; oceanic crust; crack;
Oman drilling Project; IODP hole 1256D
2782.
Country-wide exploration for graphite- and sulphide-rich black shales with airborne geophysics and petrophysical and geochemical studies
Journal of Geochemical Exploration,
244
2023
ISSN: 03756742
Publisher: Elsevier B.V.
Keywords:▾
Core drilling; Deposits; Electric conductivity; Geological surveys; Geophysics; Graphite; Infill drilling; Magnetic susceptibility; Oil shale; Sampling; Stratigraphy; Airborne geophysics; Black shales; Ferrimagnetics; Finland; Geophysical measurements; Greenschist; Monoclinics; Sample sets; Sulphide; Sulphide deposits; graphite; host rock; hydrocarbon exploration; hydrocarbon generation; petrography; shale; sulfide; Sulfur compounds
Abstract: ▾ Black shales host critical raw materials such as graphite and cobalt and occur in the vicinity of many types of sulphide deposits. We report the procedure for country-wide mapping of graphite- and sulphide-rich rocks and the chemical and petrophysical data of 319 samples we selected from sulphide occurrences and mines in Finland. Even though black shales are rarely outcropped in glaciated and deeply weathered terrains, they can be traced with geophysical surveys. In the Precambrian of Finland, where the metamorphic grade varies from greenschist to granulite facies, systematic airborne geophysical surveys revealed stratigraphy-related, coupled magnetic and electrically conductive patterns. Electrical conductivity was related to the graphite and sulphide contents, producing continuous and bending electromagnetic anomaly patterns. The magnetic anomalies, if present, resulted from ferrimagnetic monoclinic pyrrhotite. The petrophysical properties of black shales varied in our sample set. The densities were mainly between 2700 and 3000 kg/m3, with the mean density ~ 2800 kg/m3, where the amount of graphite had a reducing effect on density whereas sulphides increased it. The average magnetic susceptibilities were about 6000·10−6 (SI), but they showed wide variation, depending on the abundance of ferrimagnetic monoclinic pyrrhotite. The electrical conductivity of black shales appeared to be positively related to the abundance of monoclinic pyrrhotite. Conductivity variation, 1–105 1/Ωm was based on laboratory determinations of apparent resistivities. We correlated an airborne magnetic and electromagnetic survey with petrophysical and chemical data from altogether 319 drill core samples containing >1 % graphitic C and >1 % S. The samples were selected during 2009–2011 from 102 drill cores all over Finland except for the Talvivaara–Outokumpu region, which was studied during previous projects. The black-shale-hosted Talvivaara Ni–Zn–Co–Cu deposit is currently being mined. The maximum graphite concentration in the country-wide sample set was 34.3 %, and the median value was 5.7 %, a lower value than reported from the Talvivaara black-shale-hosted sulphide deposit (7.6 %). S, Co, Cu, Fe and Ni concentrations were also lower in our sample set on average than in the Talvivaara ore. However, the maximum concentration in our sample set was 397 mg/kg for Co, 0.36 % for Cu, 40.8 % for Fe and 0.28 % for Ni. The developed black shale mapping procedure can be directly applied in other parts of the world in terrains with greenschist to granulite facies regional metamorphism. Information on basic petrophysical properties, i.e., density, magnetic and electric properties, are needed to explain geophysical anomalies. If the metamorphic grade is lower than greenschist facies and there is no graphite, sulphides will increase the electromagnetic properties. If ferrimagnetic pyrrhotite exists, susceptibility increases, as well as remanence. The black shale database covering the whole of Finland is used not only in exploration and bedrock mapping, but also in regional planning and for environmental risk analyses, because sulphide-rich black shales may cause acid rock drainage when exposed to weathering and the quality of surface water and groundwater may suffer from black shale bedrock and glacial till. The scale limitations given by airborne geophysics may request detailed studies in selected sites. © 2022 The Author(s)
2781.
Continental geological evidence for Solar System chaotic behavior in the Late Cretaceous
Bulletin of the Geological Society of America,
135
(3-4)
712 – 724
2023
ISSN: 00167606
Publisher: Geological Society of America
DOI:10.1130/B36340.1
Keywords:▾
China; Songliao Basin; Binary alloys; Earth (planet); Lead alloys; Orbits; Uranium alloys; Chaotic behaviour; High resolution; Lacustrine sequence; Late cretaceous; Magnetic reversal; Milankovitch cycle; Orbital parameters; Songliao basin; System solution; U-Pb ages; age determination; chaotic dynamics; Cretaceous; Earth; Mars; reconstruction; solar cycle; solar system; stratigraphy; uranium-lead dating; Stratigraphy
Abstract: ▾ The Earth’s geologic record of Milankovitch cycles closely tracks Solar System solutions for the past 50 million years. Prior to 50 million years ago (Ma), however, the solutions lose accuracy rapidly due to chaotic behavior of the Solar System. Here we reconstruct a 10.173 million year-long record from 82.358 Ma to 92.531 Ma of Earth’s orbital parameters from a continental lacustrine sequence in the Songliao Basin, China, constrained by four in situ high-resolution radioisotopic U-Pb ages and magnetic reversal stratigraphy. Analysis of thorium and ostracode shell abundance records from the Songliao Basin reveal evidence for two chaotic secular resonance transitions in the orbital motions of Earth and Mars from 85.2 Ma to 91.55 Ma. The evidence validates similar observations in western North American marine stratigraphy. A unique phasing between the observed orbital eccentricity and obliquity modulations may explain the anoxic events that occurred in both marine and continental environments during this time. Taken together, the continental and marine stratigraphic evidence demonstrates a strong global reach of Late Cretaceous Milankovitch cycles, and provides an important constraint on Solar System chaoticity and the calculation of accurate orbital solutions prior to 50 Ma. © 2022 Geological Society of America
2780.
Climate-controlled sensitivity of lake sediments to record earthquake-related mass wasting in tropical Lake Towuti during the past 40 kyr
Quaternary Science Reviews,
305
2023
ISSN: 02773791
Publisher: Elsevier Ltd
Keywords:▾
Catchments; Earth system models; Earthquakes; Fault slips; Sediments; Stratigraphy; Strike-slip faults; Tropics; Indonesia; Lake level changes; Lake sediments; Late Pleistocene; Mass transport deposit; Mass wasting; Paleoclimates; Paleoseismology; Seismic stratigraphy; Sulawesi/indonesia; Lakes
Abstract: ▾ Located at the triple junction of the Pacific, Eurasian and Sunda plates, the Island of Sulawesi in Indonesia is one of the most tectonically active places on Earth. This is highlighted by the recurrence of devastating earthquakes such as the 2018 Mw 7.5 earthquake that damaged the city of Palu and caused several thousand fatalities in central Sulawesi. The majority of large-magnitude earthquakes on Sulawesi are related to stress release along major strike-slip faults such as the Palu-Koro Fault and its southern extensions, the Matano and Lawanopo Faults. To date, information on the frequency and magnitude of past major events on these faults is limited to instrumental records and historical sources restricted to the last century, whereas information from natural archives is completely lacking. Lake-sediment records can fill this gap, but a detailed assessment of the various factors that influence the sensitivity of sediment successions to past earthquakes is required to evaluate their suitability. Lake Towuti, situated in Eastern Sulawesi, is known for its paleoclimate record and also promises to be a key site to generate a paleoseismology record for Sulawesi. The lake lies close to the highly active Matano and Lawanopo strike-slip faults and thereby is an ideal archive for past earthquakes that have occurred in the surrounding area. Here we combine high-resolution chirp seismic data with lithostratigraphic and petrophysical data of sediment piston cores to assess the recurrence of seismically generated mass-transport and turbidite deposits. Three major seismic-stratigraphic units are distinguished in the upper ∼10 m of the sediment succession and linked to differences in the frequency of mass-wasting during the past 60 kyrs. The evidence of a more turbidite-prone period between 12 and 40 ka is roughly coincident with a dry phase and associated lake-level lowstand during the last glacial period at Lake Towuti. Hence, we suggest that climate strongly influences the sensitivity of slopes to fail during seismic shaking in this tropical setting as a consequence of lowstand-forced sediment redeposition from the shelves onto the slopes and into the basins. As climate significantly impacts the sensitivity of the lacustrine sediments to record earthquake-related mass wasting deposits, we suggest that the frequency of mass-transport deposits can additionally be employed as a quantitative indicator for past changes in hydroclimate in these tropical settings. © 2023 The Authors
2779.
Eastward extension of the Solonker Suture beneath the central Songliao Basin, NE China: Evidence from a deep seismic reflection profile
Gondwana Research,
119164 – 171
2023