Katian (Upper Ordovician) carbon isotope chemostratigraphy in the Neixiang area, central China: implications for intercontinental correlation

AbstractThe Katian (Upper Ordovician) Shiyanhe Formation at the Sigang section, Neixiang area, Henan Province, central China, has been investigated for carbon isotope (δ13Ccarb) chemostratigraphy. The carbon isotopic data document signal between the two major Ordovician positive shifts in δ13C, the early Katian Guttenberg and the Hirnantian excursions. The Kope (Ka1/2), Fairview (Ka2/3), Waynesville (Ka3/4), Whitewater (Ka4) excursions and a doubtful Elkhorn (Ka4) excursion are identified herein. The continuous and well-defined conodont zonal succession of the Sigang section provides a secure biostratigraphic framework for the mid-late Katian carbon isotope chemostratigraphy in China. Correlation between carbon-isotope data curve and the relative sea-level changes shows no clear correspondence, and hence the sea-level change is probably not the main driver of δ13C excursions during the Katian. Intercontinentally, the mid–late Katian carbon isotope excursions, identified mainly in the North American and Baltoscandian successions, are useful for improving long-distance stratigraphic correlations. This further suggests that these excursions represent global perturbations in the carbon cycle.

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Carbon isotope stratigraphy and the problem of a pre-Tommotian Stage in Siberia

Geological Magazine ◽

10.1017/s0016756801005684 ◽

2001 ◽

Vol 138 (4) ◽

pp. 387-396 ◽

Cited By ~ 25

Author(s):

ARTEM KOUCHINSKY ◽

STEFAN BENGTSON ◽

VLADIMIR V. MISSARZHEVSKY ◽

SHANE PELECHATY ◽

PETER TORSSANDER ◽

...

Keyword(s):

Carbon Isotope ◽

Siberian Platform ◽

Lower Cambrian ◽

Isotopic Data ◽

Sequence Stratigraphic ◽

Anabar Uplift ◽

Carbon Isotopic ◽

The North ◽

Isotope Stratigraphy ◽

Isotopic Variations

Carbon isotopic oscillations are useful to elucidate the stratigraphy and biogeochemical events around the Precambrian–Cambrian transition. New isotopic data from the Manykaj and Emyaksin formations of the eastern Anabar Uplift (Siberia) help to correlate the Lower Cambrian and Neoproterozoic–Cambrian transitional beds across the Siberian Platform. The similarity of trends and amplitudes of the carbon isotopic curves, together with biostratigraphic and sequence-stratigraphic markers from the Anabar Uplift, provide a precise correlation with the southern part of the Siberian Platform. Diagenesis of argillaceous limestones of the Emyaksin Formation has apparently not affected the primary isotopic variations. The resulting curve is nearly identical in sections about 100 km apart in the Tommotian–Atdabanian portion of the formation. Relatively frequent and pronounced isotopic oscillations in the lower beds of the Emyaksin Formation fit between features I and II of the southern Siberian isotopic reference scale but are undetected therein owing to the depositional hiatus at the base of the Tommotian Stage in its type section. This confirms the transgressive onlap from the north suggested by previous studies, and makes the appearance of the Cambrian skeletal fossils on the Siberian Platform less abrupt. The hiatus in the south appears to embrace at least two biostratigraphic zones as recognized in the north. The case is strengthened for a pre-Tommotian Cambrian Stage in Siberia, the biostratigraphic framework for which has been elaborated earlier.

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Sequence stratigraphy, chemostratigraphy and facies analysis of Cambrian Series 2 – Series 3 boundary strata in northwestern Scotland

Geological Magazine ◽

10.1017/s0016756816000947 ◽

2016 ◽

Vol 155 (4) ◽

pp. 865-877 ◽

Cited By ~ 5

Author(s):

LUKE E. FAGGETTER ◽

PAUL B. WIGNALL ◽

SARA B. PRUSS ◽

YADONG SUN ◽

ROBERT J. RAINE ◽

...

Keyword(s):

Sea Level ◽

Sequence Stratigraphy ◽

Carbon Isotope ◽

Sea Level Changes ◽

Carbon Isotopic ◽

Carbonate Carbon ◽

Carbon Isotope Excursion ◽

Isotope Record ◽

Laurentian Margin ◽

Sequence Boundaries

AbstractGlobally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland,Olenellusis found after the negative peak of the carbon isotope excursion but before sequence boundary formation.

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Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia

Geological Magazine ◽

10.1017/s001675689900223x ◽

1999 ◽

Vol 136 (1) ◽

pp. 49-62 ◽

Cited By ~ 59

Author(s):

LEHO AINSAAR ◽

TÕNU MEIDLA ◽

TÕNU MARTMA

Keyword(s):

Isotopic Composition ◽

Sea Level ◽

Thermohaline Circulation ◽

Carbon Isotopic Composition ◽

Shelf Area ◽

Carbonate Sediments ◽

Sea Level Changes ◽

Middle Ordovician ◽

Carbon Isotopic ◽

The North

An episode of remarkable biotic, climatic, sea-level and facies changes took place during the late Viruan (Caradoc) epoch in the Baltoscandian area. We studied the carbon isotopic composition of carbonate sediments from this period. Data on the stable carbon isotopic composition of whole-rock carbonates from three south Estonian core sections, together with those on ostracode, distribution are presented. In two core sections, a positive δ13C shift of 2 ‰ was revealed in the upper part of the Keila Stage (mid-Caradoc). The comparison of isotope and ostracode data in the sections suggested the occurrence of a gap of late Keilan age in the marginal area of the basin equivalent to the North Estonian Confacies Belt. The beginning of the excursion approximately coincided with climatic and sea-level changes in the shallow shelf area. The peak of the late Keilan excursion preceded the biotic crises and maximum black shale accumulation in the Baltoscandian palaeobasin. An approximately synchronous carbon isotopic event has been reported from North America, referring to a possible global oceanographic event in the Caradoc epoch. Although the positive carbon isotopic excursion and related environmental events of the late Keilan age have some unique features, they show more similarities to the end-Ordovician and Silurian events, characterized by oceanic change from stratified state to thermohaline circulation state, than to warm anoxic events related to eustatic sea-level rise.

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First record of the Hirnantian (Upper Ordovician) δ13C excursion in the North American Midcontinent and its regional implications

Geological Magazine ◽

10.1017/s0016756806002469 ◽

2006 ◽

Vol 143 (5) ◽

pp. 657-678 ◽

Cited By ~ 87

Author(s):

STIG M. BERGSTRÖM ◽

MATTHEW M. SALTZMAN ◽

BIRGER SCHMITZ

Keyword(s):

South Africa ◽

Sea Level ◽

North American ◽

First Record ◽

Sea Level Changes ◽

Upper Ordovician ◽

The North ◽

Study Interval ◽

First Time ◽

North And South

The most prominent of the two major global δ13C excursions in the Ordovician, the Hirnantian δ13C excursion (HICE), which is previously recorded from the uppermost Ordovician in a few sections in Nevada, Quebec, Arctic Canada, Baltoscandia, Scotland and China, is documented for the first time from the North American Midcontinent. Samples through the Girardeau Limestone and Leemon Formation in Missouri and Illinois show elevated δ13C values of +4‰ to +5‰. Although not determined precisely, the beginning of the HICE is likely to be in the upper part of the Orchard Creek Shale, and it ends in the upper Leemon Formation. Being extraordinarily useful chronostratigraphically, the presence of the HICE makes it possible to provide a firm dating of the study interval, whose age has long been controversial. Comparison between the study sections and coeval HICE sequences in North America and Europe show striking similarities, especially in sea-level history, indicating that major local lowstands reflect eustatic sea-level changes. A comparison with Hirnantian diamictite successions in North and South Africa and Argentina suggests that these lowstands correspond to two major Gondwanan glacial episodes.

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Interdecadal Baroclinic Sea Level Changes in the North Pacific Based on Historical Ocean Hydrographic Observations

Journal of Climate ◽

10.1175/jcli-d-13-00103.1 ◽

2015 ◽

Vol 28 (11) ◽

pp. 4585-4594 ◽

Cited By ~ 4

Author(s):

Tatsuo Suzuki ◽

Masayoshi Ishii

Keyword(s):

Sea Level ◽

Wind Stress ◽

North Pacific ◽

Water Mass ◽

Mass Density ◽

Baroclinic Mode ◽

Sea Level Changes ◽

The North ◽

Basin Scale ◽

The North Pacific

Abstract Using historical ocean hydrographic observations, decadal to multidecadal sea level changes from 1951 to 2007 in the North Pacific were investigated focusing on vertical density structures. Hydrographically, the sea level changes could reflect the following: changes in the depth of the main pycnocline, density gradient changes across the pycnocline, and modification of the water mass density structure within the pycnocline. The first two processes are characterized as the first baroclinic mode. The changes in density stratification across the pycnocline are sufficiently small to maintain the vertical profile of the first baroclinic mode in this analysis period. Therefore, the first mode should represent mainly the dynamical response to the wind stress forcing. Meanwhile, changes in the composite of all modes of order greater than 1 (remaining baroclinic mode) can be attributed to water mass modifications above the pycnocline. The first baroclinic mode is associated with 40–60-yr fluctuations in the subtropical gyre and bidecadal fluctuations of the Kuroshio Extension (KE) in response to basin-scale wind stress changes. In addition to this, the remaining baroclinic mode exhibits strong variability around the recirculation region south of the KE and regions downstream of the KE, accompanied by 40–60-yr and bidecadal fluctuations, respectively. These fluctuations follow spinup/spindown of the subtropical gyre and meridional shifts of the KE shown in the first mode, respectively. A lag correlation analysis suggests that interdecadal sea level changes due to water mass density changes are a secondary consequence of changes in basin-scale wind stress forcing related to the ocean circulation changes associated with the first mode.

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Thermochronology quantifying exhumation history of the Wudang Complex in the South Qinling Orogenic Belt, central China

Geological Magazine ◽

10.1017/s0016756816001047 ◽

2016 ◽

Vol 155 (4) ◽

pp. 893-906 ◽

Cited By ~ 4

Author(s):

CHUANBO SHEN ◽

DI HU ◽

CHUN SHAO ◽

LIANFU MEI

Keyword(s):

Distance Effect ◽

Central China ◽

The Tibetan Plateau ◽

Yangtze Craton ◽

Long Distance ◽

South Qinling ◽

The North ◽

The Pacific ◽

History Of ◽

Exhumation History

AbstractThe Wudang Complex located in the central part of South Qinling, has been inferred to be a segment of the Yangtze Craton involved in the orogen. In this study, the cooling/exhumation history of the Wudang Complex is revealed through combined published geochronology data and new apatite fission-track results. Three rapid exhumation episodes related to relevant geodynamic events have been identified. Previous40Ar–39Ar and (U–Th)/He data indicate that the most significant exhumation, induced by the collision between the North and South China Blocks, occurred fromc.237 to 220 Ma after long-term subsidence and sedimentation of the passive continental margin. The second exhumation event, related to the long-distance effect of the Pacific subduction, occurred during the period fromc.126 to 90 Ma. Following the late Cretaceous – Eocene peneplanation stage, the final late Cenozoic exhumation sincec.15 Ma may be attributed to the combined effect of the eastward growth of the Tibetan Plateau uplift and the Asian monsoon.

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Origin of the Late Ordovician Lepidocyclus brachiopod fauna in North America and its biogeographic significance

The Paleontological Society Special Publications ◽

10.1017/s2475262200007097 ◽

1992 ◽

Vol 6 ◽

pp. 149-149

Author(s):

Jisuo Jin

Keyword(s):

North America ◽

Sea Level ◽

North American ◽

Plate Tectonics ◽

Late Ordovician ◽

Sea Level Changes ◽

Stepping Stones ◽

Shell Size ◽

Larval Stages ◽

The North

Three rhynchonellid brachiopod genera, Hiscobeccus, Lepidocyclus, and Hypsiptycha, are the most diagnostic elements of the Lepidocyclus fauna of North America in Late Ordovician time. These are characterized by relatively large, strongly biconvex to globular shells with coarse imbricating growth lamellae and, internally, with septiform cardinal processes in brachial valves. Among the three genera, Hiscobeccus appears the earliest, now known from rocks of late Trentonian-Edenian age in the Canadian Rocky Mountains and Mackenzie Mountains. Morphologically, Hiscobeccus is distinguished from the other two genera by its open delthyrium in the pedicle valve. Early forms of Hiscobeccus show close morphological similarity to Rhynchotrema in their non-globular biconvex shells covered by strong growth lamellae only in the anterior portions. It has been suggested that Hiscobeccus evolved from the Rhynchotrema wisconsinense stock through increase in shell size, globosity, and strength of growth lamellae. Earliest species of Rhynchotrema has been documented convincingly from rocks of early Trentonian age, and the derivation of Hiscobeccus most likely took place during the mid-Trentonian. Lepidocyclus and Hypsiptycha evolved from either Rhynchotrema or Hiscobeccus by developing a pair of deltidial plates covering the delthyrium.Rhynchotrema and other rhynchonellids that evolved before mid-Trentonian time are common to the North American (Laurentian) and the Siberia-Kazakhstan paleocontinents. In contrast, Hiscobeccus, Lepidocyclus, and Hypsiptycha that evolved after the mid-Trentonian are virtually restricted to Laurentia. Therefore, Rhynchotrema marked the last successful intercontinental migration of rhynchonellids during their Llandeilian-Caradocian cosmopolitanism. The pronounced provincialism of the North American Lepidocyclus fauna may have been caused by a number of factors. Facies control is not likely the explanation because these rhynchonellids occur in nearly all the inland and marginal platform seas of Laurentia and commonly are found together in the same types of rocks. Plate tectonics and sea-level changes are considered major causes. The Ordovician rhynchonellids lived in shallow marine (intertidal-subtidal) environments and were incapable of crossing vast, deep oceanic barriers because of their sedentary mode of life and short-lived motile larval stages. The widening of the ocean between North America and Siberia, coupled with high sea-level stand, may have created a sufficiently wide oceanic barrier to interrupt faunal mixing between the two paleocontinents by late Trentonian time. Moreover, the rise in sea level would have resulted in the disappearance of island faunas, which could have served as stepping stones for intercontinental migration of shallow-water benthic faunas during low sea-level stand.

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Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic

Climate of the Past ◽

10.5194/cp-11-669-2015 ◽

2015 ◽

Vol 11 (4) ◽

pp. 669-685 ◽

Cited By ~ 23

Author(s):

C. Consolaro ◽

T. L. Rasmussen ◽

G. Panieri ◽

J. Mienert ◽

S. Bünz ◽

...

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Carbon Isotope ◽

Deep Water ◽

Planktonic Foraminifera ◽

Sediment Supply ◽

The Arctic ◽

Fram Strait ◽

The North ◽

Carbon Isotope Excursion

Abstract. We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ 13C record measured on the benthonic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the 13C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

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Annual Sea Level Changes on the North American Northeast Coast: Influence of Local Winds and Barotropic Motions

Journal of Climate ◽

10.1175/jcli-d-16-0048.1 ◽

2016 ◽

Vol 29 (13) ◽

pp. 4801-4816 ◽

Cited By ~ 38

Author(s):

Christopher G. Piecuch ◽

Sönke Dangendorf ◽

Rui M. Ponte ◽

Marta Marcos

Keyword(s):

Sea Level ◽

Wind Stress ◽

Ocean Circulation ◽

Tide Gauge ◽

Sea Level Changes ◽

Tide Gauge Records ◽

Barotropic Model ◽

The North ◽

Ocean Reanalyses ◽

Coastal Sea

Abstract Understanding the relationship between coastal sea level and the variable ocean circulation is crucial for interpreting tide gauge records and projecting sea level rise. In this study, annual sea level records (adjusted for the inverted barometer effect) from tide gauges along the North American northeast coast over 1980–2010 are compared to a set of data-assimilating ocean reanalysis products as well as a global barotropic model solution forced with wind stress and barometric pressure. Correspondence between models and data depends strongly on model and location. At sites north of Cape Hatteras, the barotropic model shows as much (if not more) skill than ocean reanalyses, explaining about 50% of the variance in the adjusted annual tide gauge sea level records. Additional numerical experiments show that annual sea level changes along this coast from the barotropic model are driven by local wind stress over the continental shelf and slope. This result is interpreted in the light of a simple dynamic framework, wherein bottom friction balances surface wind stress in the alongshore direction and geostrophy holds in the across-shore direction. Results highlight the importance of barotropic dynamics on coastal sea level changes on interannual and decadal time scales; they also have implications for diagnosing the uncertainties in current ocean reanalyses, using tide gauge records to infer past changes in ocean circulation, and identifying the physical mechanisms responsible for projected future regional sea level rise.

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