Optical Luminescence Dating Research Articles

Luminescence Chronology of Reticulated Laterites in the Humid Subtropical Mountains of South China

AbstractLaterite is a red weathering crust developed with various rocks and Quaternary loose sediments as its parent material in the tropics and subtropics regions of the world. Since the 1930s, researchers have believed that the fluvial reticulated laterite in southern China was influenced by the warm and humid climate of the Middle Pleistocene. In recent years, the remains of Paleolithic human activities are often found in the reticulated laterite of southern China. However, the study of laterite chronology is sporadic or there is no critical chronological analysis, which causes uncertainty in the identification and discussion of the ages of reticulated laterite and Paleolithic sites. In this study, a Paleolithic site found in fluvial reticulated laterite in South China was systematically tested by quartz optical luminescence dating and geomorphic process analysis. The results show that, (a) The T3 terrace, an archive of hominin activity in the study area, primarily formed between 56 and 11 ka. (b) Reticulated laterite cannot be used simply to determine the ages of the Paleolithic sites found in this stratum, and typical reticulated laterite cannot be used as a marker for climatic stratigraphy and chronostratigraphy. The fluvial reticulated laterite in the southern tropics, under suitable hydrothermal conditions, can form within tens of thousands of years or even within 10 ka. (c) Human activities can affect the burial age of reticulated laterite, and the stratigraphic diachronism of riverine terraces can also lead to an inversion in the age of reticulated laterite.

Paleosols record dry and humid paleoenvironments during the Upper Pleistocene in the Brazilian Pantanal

Information on Quaternary landscapes and paleoenvironmental changes in the interior of Brazil are scarce. One of such areas, particularly sensitive to these variations, is the modern tropical Pantanal wetland, whose alluvial deposits record paleoenvironmental and paleoclimatic changes during the late Quaternary. Based on detailed pedological and sedimentological descriptions, stimulated optical luminescence dating and analytical data we described a well-exposed sedimentary succession that crops out in slope terraces of the Aquidauana River, located in the southern area of the Pantanal. We interpret environmental changes that have occurred since the beginning of the Upper Pleistocene, and which affected sedimentation and biogeochemical processes. Basal deposits comprise cross-stratified sands, which record active fluvial sedimentation from ∼106 to ∼70 ka, a period of probable increased river discharge. Fluvial channel facies are overlaid by pedogeneized floodplain deposits, in which we recognized a pedocomplex composed of a sequence of three late Pleistocene truncated paleosol profiles and a Holocene soil profile. The two lower paleosols are Vertisols with mottling, slickensides, rhizolites and septarian glaebules of carbonate. These characteristics indicate prolonged drought periods under semi-arid to arid climates ca. ∼70 and ∼30 ka. The upper paleosol profile is a Planosol (Ultisol) with block structure, waxiness, iron glaebules, and manganese films, pointing to prevailing humid climates during the terminal Pleistocene (since ∼30 ka). Covering this truncated Planosol is a layer of fine to medium-grained Holocene sands, with development of a horizon A of an Arenosol (Entisol). These paleoenvironmental changes correlate with regional changes in precipitation deduced from speleothems in nearby plateaus and in southeastern Brazilian sites.

Identification of active fault topography along the Kishtwar Fault, Jammu and Kashmir, Northwest Himalaya, India

Kishtwar region of Jammu and Kashmir, India has been investigated to identify the traces of active faults preserved in the topography of the area. The objectives were achieved by geomorphic mapping with the help of satellite imageries (Cartosat-1 with 2.5 m resolution), detailed geological field investigations, shallow sub-surface geophysical mapping and the optical luminescence dating. Active tectonic landforms mapped in this study include Kishtwar rhombohedral basin, fault scarps, drainage offset, deformed recent sediments, uplifted lacustrine sediments and faulted river terraces. The evidence of active extensional topography reported here is from the compressional tectonic regime of NW Himalaya and is represented by the ~ 10 km long and 2–3 km wide Quaternary basin, interpreted as a tectonic graben. The basin is vaulted by normal faults, where master fault and the antithetic fault show continuous and en echelon behaviour respectively. The presence of normal fault system bounding the basin/graben, lead to hypothesize that the releasing bend of Kishtwar strike-slip fault is responsible for their origin. Detailed field investigation along these faults led to highlight their active nature and future prospects for palaeoseismic investigations. The active nature of these faults is supported by dip-slip movement, fault scarp, fault rupture and displacement in the Holocene and recent sediments. The spatial distribution of these features has been confirmed with the help of Ground Penetrating Radar (GPR) survey. Optically Stimulated Luminescence (OSL) dating of the deformed units demonstrate that the displacement along the Kishtwar fault has occurred between 16.35 ± 2.13 to 13.14 ± 0.91 ka and 13.14 ± 0.91 to 7.89 ± 0.71 ka.

Using thermoluminescence signals from feldspars for low-temperature thermochronology

Abstract Natural thermoluminescence (TL) signals from feldspar crystals extracted from thermally stable drill cores ( T = − 4.1 − 60.2 ∘ C) exhibit a strong dependence on geologic and laboratory thermal conditions. As burial temperature increases, the position of the TL glow curve at half-maximum intensity (i.e., the T 1 / 2 parameter) shifts to higher measurement temperatures. This shift is also observed following isothermal treatments in the laboratory. This relationship can be explained using a kinetic model originally developed for the optical luminescence dating of feldspar grains. The thermal history of a sample is preserved in the degree of electron trap saturation as a function of thermal detrapping probability, which varies with recombination distance. A natural feldspar sample contains a range of thermal stabilities: the least stable traps will remain empty, the most stable will be full, and those traps which are partially filled will, in the case of thermal equilibrium, be diagnostic of the storage temperature. The T 1 / 2 parameter of a TL glow curve reflects which sites remain occupied. This interpretation is further borne out by additive dose measurements which illustrate that samples buried at lower temperatures are fully saturated at lower TL measurement temperatures ( ∼ 200 − 300 ∘ C) relative to warmer samples. This signal is estimated to be useful in rapidly-cooling bedrock and should grow measurably for ∼ 10 2 − 10 6 years.

Subterranean transport and deposition of quartz by ants in sandy sites relevant to age overestimation in optical luminescence dating

An artificial layered sandy site was created using a combination of native sand and colored sand (3 parts native uncolored quartz, 1 part colored quartz) in Apalachicola National Forest near Tallahassee, Florida. Twelve layers of sand, each 1 by 1 m in horizontal extent by 10 cm in thickness were emplaced to a depth of 2 m followed by implantation at the surface of a Florida harvester ant (Pogonomymrex badius) colony (the lower two layers were 50 cm thick). The colony excavated a nest, and after 7 months, the sand layers were excavated to the base to test the hypothesis that sand grains were moved upward within the ant nest without reaching the surface. The ants penetrated 11 of the 12 colored layers reaching a depth of 130 cm. Thirty nine sticky-acetate peels of ant chamber floors were collected and colored sand grains were counted under a microscope. More than 16,000 grains were identified in layers that did not originally host them. Of these, more than 80% were unambiguously moved upward. This means that possibly as many as 54,000 upwardly mobile grains were present (ratio of 3:1 uncolored to colored). In relation to optical luminescence (OSL) dating, this means that grains that would not have been optically zeroed by transport to the surface (defined here as subterranean-transported) were present in abundance, and that if the site was ancient, there would have been found many grains that were older than the layers they presently reside in, even if only one colony of harvester ants had disturbed the layers. This is in addition to the fact that backfilling of chambers and tunnels may contribute even more significantly to the presence of a subterranean-transported component of an OSL sample. We conclude that ants can significantly affect the age distributions in sandy archaeological sites. Multiple examples of such disturbances have been documented in the literature. Most relevant to our results are recent studies of the OSL chronology of Pre-Clovis-age and Palaeoindian age archaeological sites in sandy environments in North America that may have been compromised by ant bioturbation of quartz sand grains. Here we have examined in detail the potential effects of one episode of ant nest-building on the age overestimation of affected sediments. From this we found that as few as 12 episodes of bioturbation involving backfilling of chambers in the same volume of sand could lead to the presence of 1 contaminant grain per 50 grains of sample.

Abrupt climatic events during Oxygen Isotope Stage 3 recorded in terrestrial sediments in the Netherlands: a multi-proxy approach

Fine-grained sandy–silty channel–belt and floodplain deposits of the Berettyó–Körös Rivers, a main eastern transverse tributary system of the modern Tisza River in the eastern part of the Pannonian Basin, were deposited during the Late Pleistocene under net subsiding conditions. The palaeo-drainage network pattern of a 2500 km2 large part of the alluvial plain was reconstructed based on interpretation of airborne photographs and analysis of 18th century topographic maps, which show the natural river patterns that predate the introduction of river regulation schemes. The investigation showed that a large meandering river system, with two main channel belts surrounding a floodbasin, entered the alluvial plain from the northeast, and a braided river entered the alluvial plain from the southeast. Detailed sedimentary logs of seven continuous corings and several sand and clay-pit sections were used to characterize different alluvial units. Optical luminescence dating (OSL) of 25 quartz samples and four 14C datings showed that the sediments are of Late Pleniglacial to Late Glacial age. Transport directions inferred from heavy mineral analyses combined with the OSL ages strongly suggest that the large meandering system represents the palaeo-Tisza River, which supposedly flowed along the northeast–southwest striking Érmellék depression during the Late Pleniglacial. The braided river can be regarded as a precursor to the Fekete and Fehér–Körös Rivers, which entered the alluvial plain from the southeast during the Late Glacial. The interpretation of seismic profiles, field measurements of neotectonic activity, and variations in thickness of sediments along the studied profile revealed that river development was largely controlled by subsidence along the Érmellék depression until 14 to 16 ky, and by uplift of the southeastern part of the catchment area. The studied fluvial successions also document the response of the palaeo-Tisza and Körös system to the climate changes of the Weichselian Late Pleniglacial–Late Glacial period. Much of the sand from the meandering zones was deposited during the Bølling–Allerød and Ságvár–Lascaux interstadials, whereas some dated sand units from the braided zone represent the Older and Younger Dryas. The error ranges of OSL dates, which often exceed the duration of Weichselian substages and subdivisions, prevented an unambiguous correlation of the studied sections with the millennial-scale climate changes of the last 25 ky. Meandering and braided river activity coexisted under different climate conditions, whereas locations of the main channel belts are related to subsidence anomalies. The results of our study thus clearly indicate that tectonics was the primary control on river development.

Optical luminescence dating of a loess section containing a critical tephra marker horizon, SW North Island of New Zealand

A new IRSL dataset is presented for the age and setting of a critical Late Glacial Maximum tephra isochron marker. The rhyolitic tephra, known as the Kawakawa Tephra, occurs as a 14 cm thick layer within a 5.9 m thick loess section overlying alluvial gravels in the Rangitikei River valley, SW North Island of New Zealand. Ages range from 21 at the base to 5 ka near the top of the loess and bracket an age of 17.0 ± 2.2 for the tephra. The new IRSL ages are in agreement with published and unpublished luminescence ages from other localities of loess, sand and ash above and below the tephra and of the tephra itself, that indicate an age of ca. 19 ka for the Kawakawa Tephra. This age is considerably younger than the generally accepted 14C 27.1 ka cal yrs BP age of the Kawakawa Tephra and highlights an unresolved discrepancy between the two dating systems.

Luminescence Dating of Beachrock in the Southeast Coast of India—Potential for Holocene Shoreline Reconstruction

Abstract Optically stimulated luminescence (OSL) dating of quartz grains extracted from beachrock on the southeast coast of India was attempted. Preliminary OSL ages of beachrock indicate that during the Late Holocene (3.6–2.1 ka) sea level along this coast was higher than at present. This observation is broadly consistent with the existing data based on radiocarbon dating of bioclasts in the beachrock, which suggests a higher sea stand during 4.3–2.3 ka. This study demonstrates the potential of optical luminescence dating of beachrock for refining sea-level chronology and shoreline evolution on the southeastern coast of India.

Fluvial responses to tectonics and climate change during the Late Weichselian in the eastern part of the Pannonian Basin (Hungary)

Fine-grained sandy–silty channel–belt and floodplain deposits of the Berettyó–Körös Rivers, a main eastern transverse tributary system of the modern Tisza River in the eastern part of the Pannonian Basin, were deposited during the Late Pleistocene under net subsiding conditions. The palaeo-drainage network pattern of a 2500 km 2 large part of the alluvial plain was reconstructed based on interpretation of airborne photographs and analysis of 18th century topographic maps, which show the natural river patterns that predate the introduction of river regulation schemes. The investigation showed that a large meandering river system, with two main channel belts surrounding a floodbasin, entered the alluvial plain from the northeast, and a braided river entered the alluvial plain from the southeast. Detailed sedimentary logs of seven continuous corings and several sand and clay-pit sections were used to characterize different alluvial units. Optical luminescence dating (OSL) of 25 quartz samples and four 14C datings showed that the sediments are of Late Pleniglacial to Late Glacial age. Transport directions inferred from heavy mineral analyses combined with the OSL ages strongly suggest that the large meandering system represents the palaeo-Tisza River, which supposedly flowed along the northeast–southwest striking Érmellék depression during the Late Pleniglacial. The braided river can be regarded as a precursor to the Fekete and Fehér–Körös Rivers, which entered the alluvial plain from the southeast during the Late Glacial. The interpretation of seismic profiles, field measurements of neotectonic activity, and variations in thickness of sediments along the studied profile revealed that river development was largely controlled by subsidence along the Érmellék depression until 14 to 16 ky, and by uplift of the southeastern part of the catchment area. The studied fluvial successions also document the response of the palaeo-Tisza and Körös system to the climate changes of the Weichselian Late Pleniglacial–Late Glacial period. Much of the sand from the meandering zones was deposited during the Bølling–Allerød and Ságvár–Lascaux interstadials, whereas some dated sand units from the braided zone represent the Older and Younger Dryas. The error ranges of OSL dates, which often exceed the duration of Weichselian substages and subdivisions, prevented an unambiguous correlation of the studied sections with the millennial-scale climate changes of the last 25 ky. Meandering and braided river activity coexisted under different climate conditions, whereas locations of the main channel belts are related to subsidence anomalies. The results of our study thus clearly indicate that tectonics was the primary control on river development.

Boulders of MIS 5 age deposited by a tsunami on the coast of Otago, New Zealand

A series of elevated imbricated boulders were investigated on the Otago coastline, southeast New Zealand, through field surveying and optical luminescence dating. By using established hydrodynamic relationships of sediment transport the energy required to move the clasts was calculated and compared to the historic record of marine inundations of that coast. The boulders are platy in shape and are over 2 m long in some cases, and are sourced from a locally outcropping conglomerate unit which appears to be the only lithology on this section of coast that erodes to produce clasts of this size. It is estimated that the boulders were deposited by a tsunami between 2 and 3 m high during the latter part of Marine Isotope Stage 5. They therefore represent the first pre-Holocene tsunami deposit and one composed of large boulders described on the New Zealand coastline.

Gulf coastal plain evolution in West Louisiana: Heavy mineral provenance and Pleistocene alluvial chronology

High Resolution Heavy Mineral Analysis (HRHMA) of late Pleistocene terrace samples, their Tertiary source rocks, and modern river sediments provided an effective tool for reconstructing sediment provenance and mapping heavy mineral provinces in southwest Louisiana. Each province, linked to a discrete source region, represents Pleistocene fluvial channel belts within which depositional activity was controlled by periods of climate, sediment supply, and sea level changes. Four coastal heavy mineral provinces have been identified. The Northern Province (NP), drained by the lower reaches of the Sabine and Calcasieu Rivers underlies level mid- and late Pleistocene coastal terrace surfaces and is distinguished by high-grade metamorphic assemblages (kyanite, staurolite, sillimanite) and abundant zircon, probably of Ouachita Mts. derivation. Transporting eroded Cretaceous, Tertiary, and Pleistocene coastal plain deposits, the modern Calcasieu and Sabine River sands in west-central and southwest Louisiana and east Texas, display identical heavy mineral composition to that of the NP. Level Late Pleistocene coastal terrace areas in the east represent the Red River Province (RRP) with dominant epidote, tourmaline, garnet, and zircon. Its mineralogy is influenced significantly by Paleozoic–Mesozoic sedimentary units that frame the drainage basin upstream. Modern Red River sands differ in their spectra both from Red River Pleistocene coastal terrace and valley terrace deposits, interpreted by temporal fluctuations in sediment supply initiating a variable contribution of detritus from different sources. Tributaries that drain formations with high concentrations of high-grade metamorphic minerals also affected Red River valley Pleistocene terrace deposits in west-central Louisiana, enriching them in kyanite and staurolite. The Mississippi Province (MP) occupies the eastern-southeastern area of the low, flat, gently seaward-sloping Prairie coastal terrace. Whereas modern Mississippi alluvium is dominated by hornblende, pyroxenes, and epidote, as the result of post-depositional dissolution, pyroxenes are rare in the MP. The Mixed Suite Province (MSP) reflects MP, RRP, and to a lesser degree, NP signatures and forms the Prairie fluvial coastal plain surface closer to the Texas state line. Raw data of the principal heavy minerals were used for statistical analysis. Statistical parameters proved consistent with mineralogy-derived reconstruction of sediment provenance and provinciality of heavy mineral suites, thus providing an independent and objective support to data interpretation. Optical and thermal luminescence dating at other Gulf locations [Otvos, E.G. (2005). Numerical chronology of Pleistocene coastal plain and valley development; extensive aggradation during glacial low sea levels. Quaternary Internat., 135 91–113.] supports the pre-Sangamon ages of the Intermediate Pleistocene terraces in the NP area. Sangamon (135–116 ka), Eowisconsin (114–76 ka), and Wisconsin (74–36 ka) dates characterize the four provinces in the low, level northern Gulf Prairie coastal plain. Refuting earlier assumptions that coastal plain aggradation occurred only during marine highstand phases, thermal and optical luminescence dates indicated that, despite the low Eowisconsin and Wisconsin eustatic sea levels of several preglacial and glacial stages and substages, coastal plain alluviation, paradoxically, recurred between 106 and 35 ka BP. An interesting outcome of our heavy mineral study is the recognition and dating of a previously undocumented, rare ash-fall event that originated in Caribbean andesitic volcanoes. It was identified by the presence of a volcanogenic heavy mineral suite, composed of pristine euhedral clinopyroxene, sphene, zircon, apatite, and hexagonal biotite. Unaffected by fluvial reworking, this suite was recovered from a MP sample, dated ca. 86 ka BP.

Nouvelles données chronologiques, technologiques et typologiques sur le Paléolithique supérieur ancien de la Plaine roumaine du Danube : le gisement de Giurgiu-Malu Rosu

The optical luminescence dating (OSL) method has been applied to loess deposits associated with a “Late” Aurignacian industry already dated by 14C. Both dating results are in good agreement. This study demonstrates that lithic industries with some aurignacian tools are still present few thousand years before the Last Maximum Glacial in the Romanian Danube Plain.

The Devensian periglacial record on Thanet, Kent, UK

AbstractThe Devensian periglacial record on Thanet, Kent, is traced from c. 88 to 74 ka and from c. 24 to 12 ka by optical luminescence dating of aeolian sand and silt in the periglacial stratigraphy. The record commences before 88 ka with valley cutting at Pegwell Bay. Valley filling had begun by c. 88 ka and continued to at least 74 ka, coinciding with a major episode of loess deposition in Europe. Permafrost aggradation commenced before c. 21 ka, brecciating near‐surface chalk by ice segregation in permafrost and the overlying active layer. Deposition of aeolian sand (coversand) occurred at c. 24–21 ka, correlating with the Older Coversand I in mainland Europe. Permafrost degradation commenced at c. 21 ka, probably due to climate warming during Greenland Interstadial 2. The resulting active‐layer deepening through ice‐rich permafrost initiated soft‐sediment deformation and formation of large‐scale patterned ground in an active layer c. 2 m deep. Renewed permafrost aggradation between c. 21.25 and 18 ka coincided with climate cooling during Greenland Stadial 2c and led to cryoturbation in a thinner active layer. Final permafrost degradation commenced no later than c. 14.7 ka, that is, the start of Greenland Interstadial 1e, and may have occurred to some extent during the climate warming associated with Greenland Stadial 2b (c. 19.5–16.9 ka). Renewed deposition of aeolian sand took place at c. 15.5 ka, coincident with loess deposition on Thanet. A final episode of aeolian sand deposition occurred at 12 ka, correlating with the Younger Coversand deposits that are widespread in northwest Europe and formed during Greenland Stadial 1. Copyright © 2003 John Wiley & Sons, Ltd.

Optical luminescence dating of uplifted marine terraces along the Akatore Fault near Dunedin, South Island, New Zealand

The south Otago coast is characterised by a flight of marine terraces which have formed and been uplifted in Quaternary time. Optical luminescence dating along the recently active Akatore Fault has provided burial ages for beach sands resting upon a wave‐cut platform in the up thrown block that are equal to or younger than 71 ± 14 ka, and a burial age of c. 20 ka for the loess cap. The ages on beach sands clearly indicate that motion on this fault has been relatively limited since the last interglacial, while the loess date constrains the age of at least one faulting event on the Akatore Fault at this locality, and two events on the fault farther south, to be younger than 21 ka. The 6 m high (above high sea level) sand units in the terrace shown here to date from the late part of the last interglacial, suggest that sea levels at that time (oxygen isotope substage 5a) may not have been as low as ‐18 m, but rather closer to modern sea level. These applications of optical luminescence dating, using green light and infrared stimulation of quartz luminescence, constitute a new approach to studying tectonic rates on faults and paleo‐sea levels.

The Timing and Environmental Significance of Late Quaternary Linear Dune Development in Western Zambia

Optical luminescence dates for 19 samples from the degraded linear dune field of western Zambia indicate multiple periods of regional dune building for the late Quaternary, 32,000–27,000, 16,000–13,000, 10,000–8000, and 5000–4000 yr ago. These dates show that the last glacial maximum was not the only time when dune construction, commonly linked to marked aridity, occurred in central-southern Africa during the late Quaternary. Whereas rainfall significantly less than today's ca. 1400 mm yr−1 is a prerequisite for dune construction in the area, adequate sediment supply also determines dune construction and preservation, so that dune building cannot be simply and singularly linked to marked aridity. The Zambezi River system is proposed as an important source of dune sediments, with the nature of linear dune activity explaining why stacked sediments preserve several phases of dune formation. Chronologies of dune construction in western Zimbabwe and the southwest Kalahari are in broad agreement with our Zambian chronology and support a model of rainfall shifts along a SW–NE gradient, with some notable disparities. These are probably a function of interregional sediment supply differences, the number of samples used to delimit constructional periods, and the multicausal nature of forcing mechanisms.