Late Quaternary Shorelines Research Articles

Disentangling the impacts of climate and human colonization on the flora and fauna of the Australian arid zone over the past 100 ka using stable isotopes in avian eggshell

Abstract Throughout the Quaternary, the flora and fauna of Australia evolved and adapted to the high-amplitude, low- and high-frequency climate changes that characterized the ice-age cycles. However, during the last glacial cycle, between ∼120 and 15 ka, unprecedented irreversible changes in flora and fauna occurred, and in that same interval modern humans established their first firm presence in the landscape. Disentangling the impacts of the first-order trend toward a colder, drier planet through the Late Quaternary from the impacts of human colonization has been challenging, from both the chronological and paleoenvironmental perspectives. We utilize the stable isotopes of carbon and oxygen preserved in near-continuous time series of Dromaius (emu) eggshell from five regions across Australia to provide independent reconstructions of ecosystem status and climate over the past 100 ka. Carbon isotopes are determined by the diet consumed by the female bird, whereas oxygen isotopes record the status of local moisture balance in the months prior to breeding. Together, δ13C and δ18O provide ecosystem status and climate from the same dated sample, reducing correlation uncertainties between proxies. Combined with recent improvements in the chronologies of Late Quaternary shorelines fringing inland lake basins and deflation during arid times, these data collectively reaffirm that Australia generally became increasingly, albeit irregularly, drier from the last interglaciation through to the last glacial maximum. Dromaius eggshell δ18O documents peak aridity between 30 and 15 ka, but shows no evidence of exceptional climate change between 60 and 40 ka. In contrast, Dromaius δ13Cdiet documents an irreversible loss of the majority of palatable summer-rainfall-related C4 grasses across the Australian arid zone between 50 and 45 ka, about the same time that the giant megafaunal bird, Genyornis, became extinct, and coincident with human dispersal across the continent. Our data indicate that changes unique to Australia occurred between 50 and 45 ka that led to a new climate-vegetation relationship and an overall reduction in effective moisture across much of the continent. The large summer-rainfall-dominated lakes of interior Australia failed to re-fill subsequently, despite a wide range of global climate states. A full explanation for the mechanisms behind these changes remains elusive, but they are almost certainly related to human agency. Plausible explanations include a change in fire regime resulting from human-lit fires, a change in fire regime following extinction of megafaunal browsers, and/or a threshold response to increasing aridity. Of these, the climate change explanation is least likely, given the lack of evidence for unprecedented aridity between 60 and 40 ka, and the successful adaptation of Australian ecosystems to 2.5 Ma of similar changes.

Testing rival tectonic uplift models for the Lechaion Gulf in the Gulf of Corinth rift

Abstract: The Gulf of Corinth, central Greece, is a rapidly extending continental rift, the eastern part of which bifurcates into the active northern Alkyonides Gulf and the southern Lechaion Gulf. The Lechaion Gulf is considered an inactive relict of early rifting, yet the presence of late Quaternary shorelines is evidence of continuing uplift of the north, east and south margins of this basin. Models to explain uplift include uplift on the footwall of the southern Alkyonides Gulf fault system and the Xylocastro–Perachora faults or ‘regional' isostatic uplift independent of fault slip. These models are tested by comparing predicted spatial uplift trends with those observed. Uplift rates since Marine Isotope Stage 7 of 0.31 ± 0.04 mm a −1 on the Lechaion Gulf north coast are explained as displacement on the footwall of active faults. However, the south coast uplift cannot be explained by footwall uplift and is evidence for isostatic uplift that probably affects the whole of the southern Gulf of Corinth rift. Isostatic uplift rates of 0.22 ± 0.01 mm a −1 at the Corinth canal increase westward towards the mouth of the Lechaion Gulf where it meets the modern rift, the Gulf of Corinth. Supplementary material: Details of Holocene marine notches that identify raised shorelines from exposures on the southern Perachora peninsula between Heraion and Loutraki, and of the cumulative displacement of sequences by minor faults on the Isthmus, exposed in the Corinth canal walls, are available at http://www.geolsoc.org.uk/SUP18429 .

Constraints on vertical crustal motion for long baselines in the central Mediterranean region using continuous GPS

GPS-determination of vertical crustal velocity relative to a globally defined reference frame is limited by the accuracy of the reference frame origin and scale. However, the precision of relative vertical rates at regional-distance scales remains largely unexplored. We investigated the precision of regional-scale vertical velocity estimates using data from seven continuously operating GPS stations located in the central Mediterranean. The stations form a network of aperture ∼ 500 km and each has been in operation for at least 5 yr. We used published constraints on recent crustal uplift inferred from late Quaternary shoreline data to aid in the definition of a local vertical reference frame for GPS rates to facilitate an assessment of GPS vertical precision. We explored different methods of defining the local reference frame. The simplest method involves the estimation of a single scalar translation parameter. Adjusting the reference frame by this simple method yields agreement between CGPS and Holocene shoreline data sets at the level of 0.2 to 0.4 mm/yr. Relative rates determined using CGPS are also consistent with tide gauge records and sea level determined by satellite altimetry at the level of about 0.2 mm/yr. These results suggest that regional-scale relative velocity precision well below the mm/yr-level is now possible using continuous GPS.

The 87Sr/86Sr ratios of lacustrine carbonates and lake-level history of the Bonneville paleolake system

Lakes in the Bonneville basin have fluctuated dramatically in response to changes in rainfall, temperature, and drainage diversion during the Quaternary. We analyzed tufas and shells from shorelines of known ages in orderto develop a relation between 8 7 Sr/ 8 6 Sr ratio of carbonates and lake level, which then can be used as a basis for constraining lake level from similar analyses on carbonates in cores. Carbonates from the late Quaternary shorelines yield the following average 8 7 Sr/ 8 6 Sr ratios: 0.71173 for the Stansbury shoreline (22-20 1 4 C ka; 1350 m), 0.71153 for the Bonneville shoreline (15.5-14.5 1 4 C ka; 1550 m), 0.71175 for the Provo shoreline (14.4-14.0 1 4 C ka; 1450 m), 0.71244 for the Gilbert shoreline (∼10.3-10.9 1 4 C ka; 1300 m), and 0.71469 for the modern Great Salt Lake (1280 m). These analyses show that the 8 7 Sr/ 8 6 Sr ratio of lacustrine carbonates changes substantially at low- to mid-lake levels but is invariant at mid- to high-lake levels. Sr-isotope mixing models of Great Salt Lake and the Bonneville paleolake system were constructed to explain these variations in 8 7 Sr/ 8 6 Sr ratios with change in lake level. Our model of the Bonneville system produced a 8 7 Sr/ 8 6 Sr ratio of 0.71193, very close to the observed ratios from high-shoreline tufa and shell. The model verifies that the integration of the southern Sevier and Beaver rivers with the Bear and others rivers in the north is responsible for the lower 8 7 Sr/ 8 6 Sr ratios in Lake Bonneville compared to the modern Great Salt Lake. We also modeled the 8 7 Sr/ 8 6 Sr ratio of Lake Bonneville with the upper Bear River diverted into the Snake River basin and obtained an 8 7 Sr/ 8 6 Sr ratio of 0.71414. Coincidentally, this ratio is close to the observed ratio for Great Salt Lake of 0.71469. This means that 8 7 Sr/ 8 6 Sr ratios of >0.714 for carbonate can be produced by climatically induced low-lake conditions or by diversion of the upper Bear River out of the Bonneville basin. This model result also demonstrates that the upper Bear River had to be flowing into the Bonneville basin during highstands of other late Quaternary lake cycles: carbonates from the Little Valley (130-160 ka) and Cutler Dam (59 ′ 5 ka) lake cycles returned 8 7 Sr/ 8 6 Sr ratios of 0.71166 and 0.71207, respectively, and are too low to be produced by a lake without the upper Bear River input.

Late Quaternary uplift of northeastern Sicily: relation with the active normal faulting deformation

The evaluation of the vertical displacement-rate of the Late Quaternary marine terraces along the Ionian coast of northeastern Sicily (southern Italy) has been adopted as a tool to reconstruct the Late Quaternary deformation affecting the aseismic area, intervening between the Calabrian arc and the eastern Sicily seismogenic regions. The methodology adopted, based on computer elaboration of the field data, provided the amount of the uplift recorded since 124 ka, partitioned in the time, with the resolution of the oxygen isotope timescale (OIT) stages. The main result of the analysis is the recognition of a recently deformed sector of the coast, corresponding to the area of underlap between the seismogenic faults of southern Calabria and eastern Sicily. The deformation path of the Late Quaternary shorelines is consistent with the occurrence of an active normal fault in the off-shore of the area. This tectonic feature, that crosses through a main crustal barrier, represents the link between the two sets of seismogenic faults that cut through the weakened sectors of the crust. The resulting picture clearly indicates the influence of crustal properties on the geometry of the active fault belt and on the distribution of the main seismic events along the active “Siculo-Calabrian Rift Zone”.

Reviews

J.A. Kerle, Uluru Kata Tjuta & Watarrka: Ayers Rock, the Olgas and Kings Canyon, Northern TerritoryR.J. Allan, J.A. Lindesay and D.E. Parker (eds), El Niño Southern Oscillation and Climatic VariablityP.J. May, R.J. Burby, N.J. Ericksen, J.W. Handmer, J.E. Dixon, S. Michaels and D.I. Smith, Environmental Management and Governance: Intergovernmental Approaches to Hazards and SustainabilityR.W.G. Carter and C.D. Woodroffe (eds), Coastal Evolution: Late Quaternary Shoreline MorphodynamicsI.R. Wills, Economics and the Environment: a Signalling and Incentives Approach

Coastal evolution: late Quaternary shoreline morphodynamics

Journal of Quaternary ScienceVolume 11, Issue 3 p. 263-264 Book Review Coastal evolution: late Quaternary shoreline morphodynamics R. J. N. DEVOY, R. J. N. DEVOYSearch for more papers by this author R. J. N. DEVOY, R. J. N. DEVOYSearch for more papers by this author First published: May/June 1996 https://doi.org/10.1002/(SICI)1099-1417(199605/06)11:3<263::AID-JQS228>3.0.CO;2-1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue3May/June 1996Pages 263-264 RelatedInformation

Quaternary sedimentary deposits on the Cameroon shelf: Characterization of facies and late quaternary shorelines

Abstract Several high-resolution (SPARKER) seismic-reflection surveys, associated with 450 dredgings and 75 Kullenberg core samplings, allowed the definition of the main Quaternary sedimentary bodies of the Cameroon shelf. The distribution of the Holocene mantle is very uneven: its thickness reaches 40 m at the northern end of the shelf where there are sandy stratified deposits in the lower part and a High System Tract in the upper part. These deposits cross obliquely offshore and towards the south where the Holocene is either absent or localized as backfill in low-level ravines. This distribution is controlled by the Sanaga flow deflected northwards by the predominantly SW swell and by the Niger River flow driven southwards by the Guinean current. The sensu lato Pleistocene mantle is substantial in the north where fluvio-deltaic sands issued from the Nigerian complex. Southward coarse sands from the Sanaga-Nyong complex accumulate in progradient structures. In the southern part of the plateau, the Cenozoic-Mesozoic and Pre-Cambrian substratum at the outcrop is indented by extensive unevenness defining asedimentary shoals and Pleistocene-silted depressions. These depressions present paralic littoral successions towards the coast and circa-littoral to littoral successions seawards. As a result of the last eustatic movements, the roof of these successions has been planed off and has been more and less intensely modified. In some cases it is possible to date the last oscillations of the shoreline, using 14 C.

Optically stimulated luminescence dating of a late quaternary shoreline deposit, Tunisia

Quartz optical dates have been measured from high energy shoreline deposits at Hergla and Chebba, Tunisia, which may be related to a tsunami or severe storm surge. Preliminary results from two sites place the date of the ‘boulder beds’ within Oxygen Isotope Stage 5e.

Differential uplift of middle and late quaternary shorelines, northwest South Island, New Zealand

Discontinuous Pleistocene cliff-backed shorelines up to 220 m in altitude, and Holocene shorelines up to 12 m, border much of 125 km of coast from Westport to Hokitika in northwest South Island, New Zealand. The coastal terraces are up to 10 km wide where cut on soft Tertiary sediments but are narrow or absent on gneiss. By analogy with post-glacial shoreline development, Pleistocene shorelines are accepted as having been formed at the times of attainment of high interglacial sea levels. Past intraregional correlations assumed minimal differential uplift, but, as with glacial outwash surfaces inland, the raised shorelines are deformed by folding. Correlations are helped by the relations of shoreline deposits to glacial outwash gravels in the south, and by a few radiometric, mainly radiocarbon, dates. Correlations with high sea levels of deep-sea Oxygen Isotope Stages are made using the best fits of the altitudes of local sequences of shorelines to the altitudes expected assuming constant rates of uplift for each sequence. Uplift rates are between 0.5 and 0.2 m/kyr, and the uplift pattern substantially matches that of uplift of Miocene to lower Quaternary sediments. The shorelines correspond to high sea levels within Oxygen Isotope Stages 15, 13, 11, 9 (two), 7 (two), 5 (two) and 1.

Late Quaternary Shorelines in the Japanese Islands.

The recent progress of late Quaternary shoreline studies in Japan are reviewed. In the first half, outcomes of the estimation of ages and elevations of shorelines during high sea-level stand of the late Pleistocene are exemplified for five localities, Hateruma Island in the Ryukyus, Matsumae Peninsula of Hokkaido, Tanegashima Island to the south of Kyushu, Noto Peninsula in the Japan Sea side of Chubu district, and Muroto Peninsula of southeastern Shikoku. The latter half is a summary, mainly as to the elevation of shorelines of the last interglacial, and gives some informations on younger (isotope stages 5c or 5a) and the penultimate interglacial (isotope stage 7) shorelines in the Japanese Islands. There it is evidenced not only how to confirm the elevation of each shoreline but also how to determine the age of it.

Late Quaternary Shorelines of Lake Naivasha, Kenya

Summary Dr. Celia Kamau is on the staff of Kenyatta University College, Nairobi. She has carried out exhaustive research on the lake basins of the central Rift Valley, much of it in association with archaeologists. The Lake Naivasha basin in the Kenya Rift Valley contains evidence that the lake has formerly stood well above its 1972 level of about 1890 m. This evidence was located and levelling was undertaken to determine the elevation of the former high lake shoreline or shorelines. A possible beach ridge was located at an elevation of 2006–2008 m, and beach gravels of obsidian, lava and pumice occurred at many localities up to a maximum of 1990–1996 m. It may tentatively be concluded that the lake rose to a maximum level of 2000±10 m. No conclusive proof of a lower shoreline level could be found. At present a rising lake in this basin would flow southwards down the Njorowa Gorge when it reached an elevation of 1940–1950 m: lowering of the terrain in this area has clearly taken place since the time of th...

Late quaternary shore lines near Lake Ellesmere, Canterbury, New Zealand

Abstract Detailed study of the Kaitorete barrier enclosing Lake Ellesmere suggests that barrier formation took place 6 000–7 000 years ago when sea level was still rising in this area. Relic cliffs and shore platforms west of Birdlings Flat date from the last interglacial or earlier. Barrier development has now ceased and shore-line erosion is extending eastwards across the barrier.

Late quaternary shore lines near Lake Ellesmere, Canterbury, New Zealand

Abstract Detailed study of the Kaitorete barrier enclosing Lake Ellesmere suggests that barrier formation took place 6000–7000 years ago when sea level was still rising in this area. Relic cliffs and shore platforms west of Birdlings Flat date from the last interglacial or earlier. Barrier development has now ceased and shore-line erosion is extending eastwards across the barrier.

Vätterbäckenets Senkvartära Strandlinjer

Abstract A relationship is indicated between gradients and ages of Late Quaternary shorelines of the Vattern basin in south central Sweden, based on the presumption that the change of the gradients of raised shorelines caused by unequal land uplift can be expressed by an exponential function of time. The numerical calculations are mainly based on formerly published data which are critically examined. The author finds that the proposed function well fits the gradients of shorelines developed in the period about 8000 B.C. to present time. A detailed summary and figure texts in English are added.