Cross-basin Correlation Research Articles

New data on the palynostratigraphy and paleoenvironments of the late Miocene (Tortonian) Quifangondo Formation in the Cabo Ledo section, Kwanza Basin, Angola

A detailed palynostratigraphic and palynofacies analysis, associated with a lithological control, was carried out on eleven outcrop samples from the Quifangondo Formation in the Cabo Ledo (Petrofina) section, Kwanza Basin, Angola. The samples yield relatively diverse and well-preserved terrestrial and marine palynomorphs. A systematic analysis of the samples enables the identification of nine spore genera and 3 species, 20 pollen genera and 13 species, and 32 dinoflagellate cyst genera and 34 species. In addition, 10 genera of other aquatic palynomorphs, such as Chlorophyceae green algae, are identified. Dinoflagellate cysts and other aquatic palynomorphs typically dominate throughout the assemblages. In this section, a combined pollen - dinoflagellate cyst zonation is used to define two palynoassociations. The first palynoassociation is middle Tortonian in age and is characterized by the presence of the pollen grain Fenestrites spinosus and the first occurrence of the dinoflagellate cyst species Selenopemphix armageddonensis. Additionally, diverse Chlorophyceae green algae dominate most of this interval samples. The second palynoassociation is assigned to the late Tortonian and is characterized by a drastic decrease in Chlorophyceae green algae, as opposed to the gonyaulacales dinoflagellate cysts. The first occurrence of the pollen grain Fenestrites longispinosus marks the transition between the palynoassociations. Lithologically, the Cabo Ledo (Petrofina) section is dominated by a claystone with an increase in the silt and carbonate components towards the upper section. The lithological data, integrated with palynostratigraphy and palynofacies, suggests that the upper part of the Quifangondo Formation was mainly deposited in an inner to middle neritic environment characterized by dysoxic conditions punctuated by periods of terrestrial inflows. Such conditions typically result from seasonal fluctuations. The age and depositional environment of the upper Quifangondo Formation inferred from this new data allows a correlation with the other Quifangondo sequences previously studied by the authors. This multi-proxy approach is important for further stratigraphic analysis with other age-controlled lithostratigraphic units in the basin. Furthermore, the improvement of paleoenvironmental and depositional models for this unit is of great importance for cross-basin correlation and future petroleum exploration plays.

Long-lived stable shelf deposition along Gondwana's southern margin during the Ordovician-Silurian: Inferences from U[sbnd]Pb detrital zircon ages of the Table Mountain Group (South Africa) and correlatives in Argentina and the Falklands/Malvinas Islands

The Ordovician-Silurian siliciclastic units of the Table Mountain Group (TMG; Cape Supergroup) of the Cape Fold Belt (CFB) are classically considered to signify a period of long-lived sedimentation along the southern margin of southern Africa. Despite its vast, prominent outcrop, meaningful interpretations regarding the provenance of the TMG, based on a representative number of UPb detrital zircon age fractions, remains lacking. Within southern Gondwana, the TMG succession is considered broadly time-correlative to the Sierra del Volcan and Balcarce formations of the Sierras Tandilia and lowermost successions of the Ventana Group of the Sierras Australes in Argentina and the Port Stephens Formation of the West Falkland Group (WFG) in the Falkland/Malvinas Islands and Natal Group (South Africa). UPb detrital zircon ages have previously been reported for the Balcarce Formation and Ventana and West Falkland groups. However, their age fractions have not necessarily been compared to the broadly time –equivalent units of the TMG. In addition to the overall scarcity of detrital zircon age data on the TMG, the validity of using conventional, qualitative probability density diagrams to display and interpret such data sets have come into question, with some authors arguing for a quantitative approach for comparing detrital zircon age data sets. A total of 1521 concordant UPb detrital zircon ages and some 330 LuHf isotope analysis for the Peninsula- and Skurweberg formations (TMG) are therefore contributed, from samples obtained throughout the CFB, along with detrital zircon age fractions for the Balcarce, Providencia and Port Stephens formations. A qualitative as well as quantitative approach to compare the UPb detrital zircon age fractions measured for these units were adapted. Noticeable similarities among detrital zircon age fractions of the Peninsula- and Skurweberg formations throughout the western to south-eastern reaches of the CFB could be confirmed by quantitative pairwise comparisons. These point towards very little change in sediment source during the deposition of the lower to upper formations of the TMG during the Ordovician-Silurian. Pairwise comparisons of the TMG zircon age fractions to those of the Balcarce-, Providencia and Port Stephens formations revealed that they all have major late Neoproterozoic to Cambrian and a late Mesoproterozoic to early Neoproterozoic age fractions in common, with some minor contributions from Ordovician-Silurian sources. Due to the overlap in prevalent detrital zircon age fractions as well as Hf-isotope signature of these units, it is difficult to assign a specific provenance area for them with a fair amount of confidence, even if dominant palaeocurrent directions are considered. A quantitative pairwise comparison among data sets of the same or time-equivalent formation did not necessarily allow for age fractions from different source areas to be sufficiently distinguished from each other. In contrast to the classically inferred Namaqua-Natal Metamorphic Complex (NNMC) as source major proto-source for the TMG, it is argued that the sediment sources were located much further to the north such as the Damara and Mozambique belts, given that parts of the NNMC were likely denudated and covered by the sediments such as those of the Nama and Vanrhynsdorp Groups during the Ordovician-Silurian. Older sedimentary successions such as the Nama Group, were likely recycled during the deposition of the TMG: a scenario which also provides a feasible explanation for the noticeable lack of Archean ages among the detrital zircon age fractions. The ages of the youngest detrital zircon fraction conforms to the maximum age of deposition as proposed in literature, although the newly reported ages does not allow for more stringent cross-basin correlations. Regions within Patagonia, considered to have been in relatively close proximity to the relevant depositories, and possibly the Famatinian Belt (Argentina), are considered the source of the youngest Ordovician-Silurian detrital zircons.

Feasibility of Multi-Year Forecast for the Colorado River Water Supply: Time Series Modeling

The future of the Colorado River water supply (WS) affects millions of people and the US economy. A recent study suggested a cross-basin correlation between the Colorado River and its neighboring Great Salt Lake (GSL). Following that study, the feasibility of using the previously developed multi-year prediction of the GSL water level to forecast the Colorado River WS was tested. Time-series models were developed to predict the changes in WS out to 10 years. Regressive methods and the GSL water level data were used for the depiction of decadal variability of the Colorado River WS. Various time-series models suggest a decline in the 10-year averaged WS since 2013 before starting to increase around 2020. Comparison between this WS prediction and the WS projection published in a 2012 government report (derived from climate models) reveals a widened imbalance between supply and demand by 2020, a tendency that is confirmed by updated WS observation. Such information could aid in management decision-making in the face of near-future water shortages.

Coupled stratigraphic and U-Pb zircon age constraints on the late Paleozoic icehouse-to-greenhouse turnover in south-central Gondwana

Abstract The demise of the Late Paleozoic Ice Age has been hypothesized as diachronous, occurring first in western South America and progressing eastward across Africa and culminating in Australia over an ∼60 m.y. period, suggesting tectonic forcing mechanisms that operate on time scales of 106 yr or longer. We test this diachronous deglaciation hypothesis for southwestern and south-central Gondwana with new single crystal U-Pb zircon chemical abrasion thermal ionizing mass spectrometry (CA-TIMS) ages from volcaniclastic deposits in the Paraná (Brazil) and Karoo (South Africa) Basins that span the terminal deglaciation through the early postglacial period. Intrabasinal stratigraphic correlations permitted by the new high-resolution radioisotope ages indicate that deglaciation across the S to SE Paraná Basin was synchronous, with glaciation constrained to the Carboniferous. Cross-basin correlation reveals two additional glacial-deglacial cycles in the Karoo Basin after the terminal deglaciation in the Paraná Basin. South African glaciations were penecontemporaneous (within U-Pb age uncertainties) with third-order sequence boundaries (i.e., inferred base-level falls) in the Paraná Basin. Synchroneity between early Permian glacial-deglacial events in southwestern to south-central Gondwana and pCO2 fluctuations suggest a primary CO2 control on ice thresholds. The occurrence of renewed glaciation in the Karoo Basin, after terminal deglaciation in the Paraná Basin, reflects the secondary influences of regional paleogeography, topography, and moisture sources.

Astronomical pacing of relative sea level during Oceanic Anoxic Event 2: Preliminary studies of the expanded SH#1 Core, Utah, USA

AbstractProximal marine strata of the North American Western Interior Basin (WIB) preserve a rich record of biotic turnover during Oceanic Anoxic Event 2 (OAE2; ca. 94 Ma), a pronounced Late Cretaceous carbon cycle perturbation interpreted to reflect global warming, widespread hypoxia, and possible ocean acidification. To develop a more robust synthesis of paleobiologic and geochemical data sets spanning this Earth-life transition, we drilled the 131 m Smoky Hollow #1 Core (SH#1), on the Kaiparowits Plateau of southern Utah, USA, recovering the Cenomanian–Turonian Boundary (CTB) interval in the Tropic Shale Formation. A 17.5 m positive excursion in high-resolution bulk carbon isotope chemostratigraphy (δ13Corg) of SH#1 characterizes the most expanded OAE2 record recovered from the mid-latitudes of the WIB.Depleted values in a paired carbonate carbon isotope (δ13Ccarb) chemostratigraphy cyclically punctuate the OAE2 excursion. These depletions correspond to intervals in the core with a higher degree of carbonate diagenesis and correlate well to an existing sequence stratigraphic framework of flooding surfaces in the shoreface facies of the Markagunt Plateau (∼100 km west). We detect statistically significant evidence for astronomical cycles in the δ13Ccarb data set, imparted by diagenesis at flooding surfaces, and develop a floating astronomical time scale (ATS) for the study interval. Stable eccentricity cycles (405 k.y.) align with stratigraphic sequences and associated trends in sedimentation rate, and short eccentricity cycles (∼100 k.y.) pace nested parasequences. These results confirm an astronomical signal and, therefore, climatic forcing of relative sea level during OAE2 in the WIB. Furthermore, cross-basin correlation of the ATS and expanded δ13C chemostratigraphy of SH#1 suggests that these transgressive-regressive parasequences modulated siliciclastic sediment delivery in the seaway and contributed to deposition of prominent rhythmically bedded CTB units across the WIB, including the Bridge Creek Limestone. The presented approach to analysis of these proximal offshore siliciclastic facies links early diagenetic influences on chemostratigraphy to astronomically modulated sequence stratigraphic horizons, and helps to resolve rates of paleobiologic and paleoenvironmental change during a significant Mesozoic carbon cycle perturbation.

Marine flooding surfaces recorded in Permian black shales and coal deposits of the Main Karoo Basin (South Africa): Implications for basin dynamics and cross-basin correlation: Discussion

The paper “Marine flooding surfaces recorded in Permian black shales and coal deposits of the Main Karoo Basin (South Africa): implications for basin dynamics and cross-basin correlation” by Götz et al. (2017) correlates the Whitehill Formation with the No. 5 coal seam on a reported prasinophyte/acritarch spike, which the authors claim indicates a basin-wide marine transgression in the Roadian. The study disregards lithostratigraphic, palynological and radio-isotopic age evidence to the contrary, which all support a Kungurian age for the Whitehill Formation, and cast doubt on the marine affinity of the acritarchs used for cross-basin correlation. Further evidence is required before a “major transgressive event” in the Karoo Basin can be supported by palynology.

Marine flooding surfaces recorded in Permian black shales and coal deposits of the Main Karoo Basin (South Africa): Implications for basin dynamics and cross-basin correlation

The marine origin of black shales in the context of the Permian postglacial development of the Karoo Basin, South Africa, is subject of an ongoing controversial discussion. Here, we present and discuss palynological and sedimentological data providing evidence of a transgressive event during the early Guadalupian. Palynofacies assemblages of the black shales of the southern basin include marine phytoplankton that exhibit peak abundance within the Whitehill shales and which also occur within siltstones and glauconitic sandstones on top of the No. 5 coal seam of the north-eastern basin. Palynostratigraphic control makes this marine signal a powerful tool for cross-basin correlation. Moreover, palynofacies analysis demonstrates a facies transition from terrestrial lacustrine and fluvio-deltaic in the northeast to deep marine in the south-western parts of the basin.

High-resolution magnetostratigraphic study of the Paleogene-Neogene strata in the Northern Qaidam Basin: Implications for the growth of the Northeastern Tibetan Plateau

The Cenozoic terrestrial, intermontane Qaidam Basin on the northeastern edge of the Tibetan Plateau contains >12km of sedimentary rocks that potentially document the accommodation of India-Asia convergence and the growth of the plateau. The chronology remains incomplete, hindering cross-basin correlation between lithostratigraphic units and their further interpretation. Here we present a high-resolution magnetostratigraphy spanning >5km of Paleogene-Neogene sequence at Dahonggou in the Northern Qaidam Basin. Based on correlation with the geomagnetic polarity time scale (GPTS), we have dated the section to being between ~52 and ~7Ma. The bottom conglomeratic unit, ranging from >52Ma to ~44Ma, was deposited in high-energy environments (e.g., alluvial fan or braided river), reflecting the earliest deformation and uplift of the basin-bounding Qilian Shan fold-thrust belt in response to India-Asia collision. In addition, we identified two major increases in sedimentation rate at 25–16Ma and after ~9.5Ma and three phases of lesser increases at 52–44Ma, 38–33Ma, and 14.6–12.0Ma. These increases in sedimentation rate are consistent with regional thermochronology and basin analysis studies, which revealed enhanced motion on basin-bounding thrust faults. We argue that these accelerated sedimentation rates indicate pulsed tectonism in the northeastern Tibetan Plateau. The pulse at 25–16Ma may further relate to phases of strong rainfall linked to an intense monsoon at that time.

Comment on the paper “Palynological records of the Permian Ecca Group (South Africa): Utilizing climatic icehouse-greenhouse signals for cross basin correlations” by K. Ruckwied, A. Götz and P. Jones (PPP, 413, 167-172, 2014)

Comment on the paper “Palynological records of the Permian Ecca Group (South Africa): Utilizing climatic icehouse-greenhouse signals for cross basin correlations” by K. Ruckwied, A. Götz and P. Jones (PPP, 413, 167-172, 2014)

Palynological records of the Permian Ecca Group (South Africa): Utilizing climatic icehouse–greenhouse signals for cross basin correlations

The Permian formations of the South African Karoo Basin play a crucial role in understanding Gondwana's climate history during this time of major global changes. In this paper we present two data sets, one from the coal-bearing Vryheid Formation (Witbank Basin) and one from the Whitehill and Upper Prince Albert formations of the DP 1/78 core (NE Karoo).Our main goal was to study the vegetation changes during this period of global warming and test if the climatic signals could be used to correlate the basinal Ecca group facies with the fluvio-deltaic coal-bearing strata of the Witbank Basin. The palynological record of the No. 2 Coal Seam of the Vryheid Formation indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. The data set of the DP 1/78 core is interpreted to represent a cool to warm temperate climate represented by a high amount of Gangamopteris and Glossopteris elements.Both data sets are very different in their composition, which can be explained by the differences in depositional environment; however, our findings reveal a different age of the studied assemblages and thus also suggest that both data sets represent different stages in the transition from icehouse to greenhouse during Permian times. As the stratigraphic correlation between the Main Karroo Basin and the peripheral basins is still under discussion, this paper provides new data to underpin the stratigraphic placement of the Whitehill Formation relative to the coal-bearing Vryheid Formation.

Weakened portfolio effect in a collapsed salmon population complex

Recent research has highlighted the importance of interpopulation diversity in fostering the stability of population complexes. Here we focus on California’s recently collapsed fall-run Chinook salmon ( Oncorhynchus tshawytscha ) and ask whether portfolio effect induced buffering is observed across the complexity hierarchy from individual populations to populations within a river basin (Sacramento, San Joaquin) to the entire Central Valley. Some buffering was observed when comparing the coefficient of variation in adult returns to a given river basin with its constituent populations but not when comparing returns to the entire Central Valley with its constituent basins because of disproportionately many fish returning to the Sacramento Basin. Moreover, we report that positive correlations in population dynamics between rivers were stronger in the last 25 years of the study compared with the first 25 years. Together, these results suggest evidence of only a weak portfolio effect that has deteriorated in recent years. Nonetheless, we also report that correlations between rivers decreased significantly with distance, suggesting that some biocomplexity remains. Our results suggest that the greatest potential for strengthening the portfolio effect would come through restoration of San Joaquin Basin populations, which at low abundance currently contribute little to the overall buffering capacity despite low cross-basin correlations.

Discussion: Basin infill architecture and evolution from magnetostratigraphic cross-basin correlations in the southeastern Pyrenean foreland basin

Research Article| February 01, 2003 Discussion: Basin infill architecture and evolution from magnetostratigraphic cross-basin correlations in the southeastern Pyrenean foreland basin J. Serra-Kiel; J. Serra-Kiel 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar C. Ferràndez-Cañadell; C. Ferràndez-Cañadell 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar L. Cabrera; L. Cabrera 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar M. Marzo; M. Marzo 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar P. Busquets; P. Busquets 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar F. Colombo; F. Colombo 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar S. Reguant S. Reguant 1Department of Stratigraphy and Paleontology, Faculty of Geology, University of Barcelona, Martí Franques s/n E-08028 Barcelona, Spain Search for other works by this author on: GSW Google Scholar GSA Bulletin (2003) 115 (2): 249–252. https://doi.org/10.1130/0016-7606(2003)115<0249:DARBIA>2.0.CO;2 Article history received: 13 Mar 2000 accepted: 12 Aug 2000 first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. Serra-Kiel, C. Ferràndez-Cañadell, L. Cabrera, M. Marzo, P. Busquets, F. Colombo, S. Reguant; Discussion: Basin infill architecture and evolution from magnetostratigraphic cross-basin correlations in the southeastern Pyrenean foreland basin. GSA Bulletin 2003;; 115 (2): 249–252. doi: https://doi.org/10.1130/0016-7606(2003)115<0249:DARBIA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search The chronostratigraphy of the middle Eocene–upper Eocene successions of the southeastern Pyrenean foreland basin has been revised by Taberner et al. (1999). This contribution was based on the correlation of the magnetic polarity stratigraphy (MPS) for several partial stratigraphic sections recording the Paleogene marine succession throughout a north-south transect of 25 km in the Vic area (northeast Spain). The new chronostratigraphic proposal by Taberner et al. (1999) is in contradiction with earlier biostratigraphic studies of the area based on larger foraminifera, implying a shift of ∼5 m.y. (range, 4.8–6.4 m.y.) in the age of the earliest marine sediments. Furthermore,... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Basin infill architecture and evolution from magnetostratigraphic cross-basin correlations in the southeastern Pyrenean foreland basin

Magnetostratigraphy, numerical dating, and facies mapping have been combined to provide the first cross-basin correlation of the Eocene southeastern Pyrenean foreland basin in northeastern Spain. This has enabled (1) depositional systems on the northern and southern margins of the basin to be dated and correlated across the basin and (2) changes in the rates of sediment accumulation in time and space to be evaluated. By sampling correlative intervals at several locations in a transect across the basin, magnetozones were detected that otherwise may have been misinterpreted due to recent magnetic overprinting, or missed by wide sampling intervals in previous magnetostratigraphic surveys. Results of this study indicate that marginal marine strata of the southeastern part of the foreland near the Vic area of Spain are 5 m.y. older than previously thought, the base of the interval (46 Ma) being middle Lutetian in age. By proposing an age of at least 35.68 Ma for the overlying Cardona evaporite unit, the age span of the marine interval in the studied part of the foreland is ~10 m.y. Contrary to earlier interpretations, no major southward migration of the southeastern Pyrenean foreland basin depocenter is recorded by the basin stratigraphy during the initial stages of middle Eocene marine sedimentation in the southern margin of the basin. However, marked basin asymmetry is observed later in its evolution as the top of the marine deposits records northward increase in the thickness of chron C17n.1n (37.47‐36.61 Ma). This asymmetry is also proved by the presence of a larger number of magnetozones within marine strata at the top of the marine interval in the northern sector. These results imply that previous age calibrations and the estimated rates of tectonic processes and sedimentation within the foreland need to be reassessed. The implications for basin infill architecture evolution through time and space, subsidence analysis, and depocenter evolution through time are addressed.