Strontium isotope composition of alpine-type ultramafic rocks in the Lake Chatuge District,Georgia—North Carolina

The ⁸⁷Sr/⁸⁶Sr ratios for a series of ultramafic rocks from the Lake Chatuge region range from 0.7023 to 0.7047, suggesting a direct upper mantle source and precluding a multiple differentiation origin for these alpine-type rocks. Higher ⁸⁷Sr/⁸⁶Sr ratios (0.7058–0.7068) for serpentinized rocks from this suite apparently reflect the influx of radiogenic ⁸⁷Sr from the surrounding gneisses and schists during serpentinization.     

The geochemistry of dissolved inorganic carbon in a surficial groundwater aquifer in North Inlet, South Carolina, and the carbon fluxes to the coastal ocean

We report measurements of pH, total dissolved inorganic carbon (DIC), total or titration alkalinity (TAlk), Ca²⁺, Mg²⁺, sulfate, and sulfide data at the seawater-freshwater interface in a shallow groundwater aquifer in North Inlet, South Carolina. These measurements and a diagenetic modeling analysis indicate that the groundwaters at North Inlet are mixtures of seawater and freshwater end-members and are seriously modified by carbon dioxide inputs from organic carbon degradation via SO₄²⁻ reduction across the entire salinity range and fermentation and CaCO₃ dissolution in the low-salinity region. DIC and TAlk are several times higher than the theoretical dilution line, whereas Ca²⁺ is slightly higher and SO₄²⁻ is somewhat lower than the dilution line. Partial pressure of CO₂ in the groundwater is extremely high (0.05 to 0.12 atm). These deviations are consistent with theoretical predictions from known diagenetic reactions. Estimated groundwater DIC fluxes to the South Atlantic Bight from either the surficial aquifer (via salt marshes) or the Upper Floridan Aquifer (direct input) are significant when compared to riverine flux in this area.     

Airborne gamma-ray and magnetic anomaly signatures of serpentinite in relation to soil geochemistry, northern California

Serpentinized ultramafic rocks and associated soils in northern California are characterized by high concentrations of Cr and Ni, low levels of radioelements (K, Th, and U) and high amounts of ferrimagnetic minerals (primarily magnetite). Geophysical attributes over ultramafic rocks, which include airborne gamma-ray and magnetic anomaly data, are quantified and provide indirect measurements on the relative abundance of radioelements and magnetic minerals, respectively. Attributes are defined through a statistical modeling approach and the results are portrayed as probabilities in chart and map form. Two predictive models are presented, including one derived from the aeromagnetic anomaly data and one from a combination of the airborne K, Th and U gamma-ray data. Both models distinguish preferential values within the aerogeophysical data that coincide with mapped and potentially unmapped ultramafic rocks. The magnetic predictive model shows positive probabilities associated with magnetic anomaly highs and, to a lesser degree, anomaly lows, which accurately locate many known ultramafic outcrops, but more interestingly, locate potentially unmapped ultramafic rocks, possible extensions of ultramafic bodies that dip into the shallow subsurface, as well as prospective buried ultramafic rocks. The airborne radiometric model shows positive probabilities in association with anomalously low gamma radiation measurements over ultramafic rock, which is similar to that produced by gabbro, metavolcanic rock, and water bodies. All of these features share the characteristic of being depleted in K, Th and U. Gabbro is the only rock type in the study area that shares similar magnetic properties with the ultramafic rock. The aerogeophysical model results are compared to the distribution of ultramafic outcrops and to Cr, Ni, K, Th and U concentrations and magnetic susceptibility measurements from soil samples. Analysis of the soil data indicates high positive correlation between magnetic susceptibilities and concentration of Cr and Ni. Although the study focused on characterizing the geophysical properties of ultramafic rocks and associated soils, it has also yielded information on other rock types in addition to ultramafic rocks, which can also locally host naturally-occurring asbestos; specifically, gabbro and metavolcanic rocks.     

沂水杂岩中超镁铁质岩的岩石地球化学特征

主要以捕虏体形式存在于沂水岩浆杂岩和变质杂岩中的超镁铁质岩石不发育鬣刺结构,岩石化学组成以高MgO和低SiO2、TiO2、K2O含量为主要特征。按岩石中是否含有橄榄石大致可以分为橄榄辉石岩和尖晶角闪二辉石岩两种,前者以强烈发育蛇纹石化为特征,矿物组合以单斜(透)辉石+橄榄石为主(偶见斜方辉石),蚀变矿物组合为蛇纹石±铬铁矿+磁铁矿±角闪石±尖晶石等;后者以局部发育滑石化为特征,矿物组合以斜方(古铜)辉石+单斜(透)辉石+尖晶石为主,其次是角闪石+磁铁矿±滑石等。岩石总体以稀土元素总量(∑REE)相对较低、LREE/HREE=1.64~4.40为特征,稀土元素的球粒陨石标准化配分图解显示所有样品均具Eu和Ce的负异常,除3个橄榄辉石岩样品外,多数样品无明显的轻稀土元素、轻重稀土元素和重稀土元素分异。岩石的微量元素组成以不相容元素Rb、Ba、U、Nb、Sr、Zr等具有明显不同的异常为特征:Ba、Nb呈现负异常,而Rb、U呈现正异常,Sr部分呈正异常,Zr和Ti负异常出现在橄榄辉石岩中,其他样品无Zr异常。样品YS0631的SHRIMP锆石U-Pb定年结果显示其变质锆石年龄值为2 560~2 605 Ma;另有一颗结晶锆石的年龄值为2 719 Ma,εHf(t)值为8.2,亏损地幔模式年龄为2 680 Ma。综上所述,该超镁铁质岩石源于地幔,形成于新太古代早期,随后遭受深熔及岩浆作用影响,经历了变质作用的改造。     

Recent vertical crustal movements from precise leveling surveys in the Blue Ridge and Piedmont Provinces, North Carolina and Georgia

Examination of two lines of repeated leveling in North Carolina and Georgia reveals

1. (1) apparent uplift at the Blue Ridge-Piedmont physiographic boundary (the AtlanticGulf drainage divide) relative to the Atlantic Coastal Plain on the east and the Valley and Ridge province to the west; and

2. (2) large tilts over short baselines superimposed upon the regional pattern in the vicinity of the nearby Blue Ridge—Piedmont geologic boundary (the Brevard fault zone). In the North Carolina profile a very pronounced correlation between topography and movement suggests possible systematic leveling error, but the observed movements appear to be larger than those normally attributed to leveling error. Thus, either refraction or rod errors are larger than expected, or the movement is real and strongly correlates with topography along this portion of the leveling line.

Anomalously high stream-gradients over both resistant and nonresistant lithologies are found around the drainage divide in North Carolina, and may be associated with the relative uplift inferred from releveling. The drainage divide in Georgia, also characterized by relative uplift on the movement profile, approximately separates two different types of stream patterns. In both cases evidence presented here suggests that stream morphology may be responding to contemporary deformation as implied by the observed elevation changes. The relative uplift in North Carolina also correlates with a positive Bouguer gravity anomaly of 30–40 mGal in the midst of the regional Blue Ridge gravity low, although the significance of the correlation is unclear.The close spatial correspondence between the zone of maximum uplift and the drainage divide suggests that the vertical movements and geomorphic anomalies may result from the same mechanism, although the nature of such is unclear. One possible mechanism could be displacement at depth along the nearby Brevard zone. However, on the basis of dislocation modeling it appears that the geodetic observations cannot be adequately explained by surface deformation associated with any simple models of slip on the Brevard zone.     

Heavy metal geochemistry and mineral magnetic characterization of urban soil in Xuzhou,China

In the present study, the enrichment, availability, speciation of heavy metals including Pb, Zn, Cu, Cd, Ni and Sb and magnetic properties of urban soils of Xuzhou (China) were investigated. All analyzed metals showed elevated concentrations compared to local background concentrations. Cadmium and Sb are the metals most enriched in the analyzed area, presenting enrichment factor, on average, of 16.5 and 8.3, respectively. By self-organizing map in combination with diagnostic ratios, the source of Sb, Cd, Cu and Pb in soils might be mainly from traffic emissions. Sequential extractions indicate that metals were primarily associated with the reducible fraction with the exception of Ni. The order of extraction efficiency of various metals was SBET (simplified physiologically based extraction test) > DTPA (diethylenetriaminepentaacetic acid) > CaCl₂. The magnetic results show that soil samples were dominated by a strong ferrimagnetic mineral component with multi- and single-domain magnetic grains. Only CaCl₂ extractable Sb was found to show significant correlations with χlf and SIRM. For both DTPA and SBET extractions, all metals investigated showed significant associations with both χlf and SIRM (saturation isothermal remanent magnetization).     

Sheet flow in a salt-marsh basin,North Inlet,South Carolina

The magnitude of sheet flow in a small South Carolina salt marsh was evaluated by comparing the storage curve for the basin based on topographic data with that based on current measurements in the main channel. The results indicate that on spring tides more than 50% of the volume of water that enters the basin enters as sheet flow over the grassy flats of the marsh. The current data also suggest that the actual storage curve may be a hysteresis loop with separate flood and ebb segments.     

Identifying a lens of frozen ground in a low-conducting layer,from dc resistivity surveys

We explore the possibility to identify a nonconducting object of a known size and geometry buried in sand-clay conducting sediments lying over frozen ground. The anomaly, which is located on the surface of the low-conducting layer, is detected with a multi-electrode dc array. Its 3D electric field is simulated as a boundary-value problem using specially designed software. The new algorithm is tested with synthetic and field data and the results are used to develop the procedure of object identification and location.     

Fluid flow and alkali transport within a metamorphic terrane, western North Carolina

This paper presents preliminary results from study of a metasedimentary terrane near the Great Smoky Mountains of North Carolina. Grade of metamorphism ranges from garnet to staurolite-kyanite zone. The stratigraphic section is dominated by metasandstone but contains thick pelitic horizons over the central portion (Anakeesta Formation) of the studied interval. Metasandstone beds contain numerous isolated calcite concretions; these react to form leucocratic calc-silicate rock at variable grade of metamorphism. Metasandstones themselves are unreactive. Study of calc-silicate reaction permits the following statements regarding fluid flow and alkali transport within the studied terrane.Within unreacted concretions, the typical mineral assemblage is quartz-oligoclase-muscovite-biotite-calcite. Reaction between micas and calcite proceeded through several stages, forming as prograde minerals andesine/bytownite, clinozoisite, zoisite, garnet, hornblende, and chlorite. Reaction occurred in the presence of a fluid phase containing a H₂O/CO₂ ratio of 9 and resulted in massive expulsion of Na₂O, K₂O and CO₂. Since postulated reactions would have produced, on average, a fluid phase whose H₂O/CO₂ ratio is only one, flow of water-rich fluid through the concretions accompanied reaction. Rough estimate suggests a volumetric ratio of external fluid to rock of at least 1.1.The metamorphic grade at which concretions undergo reaction is controlled by stratigraphic position of the host metasandstone relative to metashale. Within the Anakeesta Formation and overlying strata, extensive reaction occurs near the pelitic staurolite and kyanite isograds. Within massive metasandstones of the underlying strata, reaction is delayed to the middle staurolite-kyanite zone, 5 km upgrade. Some reaction occurs within the upper garnet zone, but this is restricted to certain thin metasandstone beds interlayered with metashale. Study of dehydration reactions within metashale demonstrates that calc-silicate reaction was coupled to production of H₂O-rich fluids within pelitic strata.Transport of H₂O-rich fluids beyond outcrop scale was by advection. Diffusion was limited to outcrop distance. On most outcrops, all isolated concretions show the same degree of reaction. But at larger scale separate metasandstone packets bounded by metashale show differing degrees of reaction. Also, all rocks underwent some degree of penetrative deformation during time of reaction. The suggestion is made that advective flow was in fact channelized into fractures within metasandstone, and that diffusion between fractures promoted reaction within outcrop-size volumes of rock. Overall direction of fluid transport was in part upsection and in part channelized within metasandstone strata. Downsection flow was limited.For the most part alkalis liberated by calc-silicate reaction appear to have left the terrane. Metasandstones do not appear to constitute a sink for alkalis, and no sink of any sort was found for sodium. Potassium metasomatism of pelitic rock did occur and is marked by conversion of chlorite to biotite. But such K deposition is limited to sections within which metashale and calc-silicate rock are within outcrop distance. No sink is evident for most liberated potassium. It is within conjecture that the liberated elements caused alkali metasomatism elsewhere within the metamorphic belt, but such an event has yet to be demonstrated.     

Zooplankton abundance and community structure in a mesohaline North Carolina estuary

The lower Neuse River Estuary is a temperate mesohaline system which forms the major southern tributary of Pamlico Sound, North Carolina. The crustacean zooplankton of this well-mixed system were sampled for a 20-month period from May 1988 through December 1989. A submersible pump was used to sample both the entire water column and the sediment surface. Seasonal dominants included the calanoid copepodsAcartia tonsa andParacalanus crassirostris in summer, the cyclopoid copepodOithona colcarva in fall, the cladoceranPodon polyphemoides in winter, and harpacticoid copepods in spring. Non-naupliar biomass over the study period consisted of 38.8%A. tonsa, 7.7%P. crassirostris, 21.2%O. colcarva 23.6% harpacticoid copepods, and 6.0% cladocerans. The remainder of the biomass consisted ofPseudodiaptomus coronatus and barnacle nauplii. Mean total copepod densities ranged from 600 m^?3 in May 1988 to 180,000 m^?3 in August 1988. Mean copepod densities for 1989 were 25,000 m^?3. Maximum densities during both years occurred during summer, with subsequent descreases throughtout the year until early spring. Abundances of total copepods, and ofAcartia tonsa in particular, were significantly correlated with water temperature, but with neither chlorophylla, phytoplankton productivity, nor any of an array of other physical or chemical variables. Regression analyses using data from this investigation, and supported by results from other regional studies, indicate that water temperature is likely the single most important variable predicting zooplankton temporal abundance in North Carolina estuaries.     

吉林红旗岭超基性岩体的锆石U-Pb年龄、Sr-Nd-Hf同位素特征及岩石成因

锆石LA-ICP-MS U-Pb年龄(220.6±2.0Ma)表明研究区超基性岩属于印支晚期岩浆活动的产物.主微量元素研究显示超基性岩具有相对较低的SiO2(43.22％～44.48％)、K2O(0.10％ ～0.17％)和Na2O(0.15％ ～2.13％)以及较高的MgO含量(29.23％ ～30.38％)和Mg#...     

Relationship of environmental geochemistry to soil degradation in Helwan catchment, Egypt

Environmental geochemistry plays an important role in understanding the distribution of major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺) in Helwan catchment, south Cairo, Egypt. Evaluation of soil mechanical erosion rate, depletion rate, exchangeable rates of base cations and sodium adsorption ratios are essential for understanding soil degradation problems in the representative Helwan catchment. Soil erosion is a natural process. It often becomes a problem when human activity causes it to occur much faster than under natural conditions. The results of the mechanical erosion rate of soil and the exchangeable rates of base cations are 1845 and 80.3 kg ha⁻¹ yr⁻¹, respectively. The high intensity of the mechanical erosion rate is probably attributed to the high specific surface area of the studied type of Vertisol, intensive application of fertilizer and industrial activities. Mechanical erosion of soil, exchangeable rate of base cations and the depletion rate of base cations are almost inexhaustible sources of sodium, and all these increase the problem of sodic soils and may affect plant productivity in Helwan catchment.     

新疆西准噶尔玛依勒蛇绿岩中镁铁-超镁铁质岩的地球化学、年代学及其地质意义

玛依勒蛇绿岩出露于玛依勒蛇绿混杂岩带中,该带位于西准噶尔造山带西南缘,是区内规模较大的一条蛇绿混杂岩带,蛇绿岩中镁铁-超镁铁质岩研究对探讨古亚洲洋古生代构造演化具有重要意义。本文选取玛依勒蛇绿岩中的镁铁-超镁铁质岩进行系统的岩石学、地球化学和年代学研究。结果表明,玛依勒蛇绿混杂岩中超镁铁质岩以富集Al_2O_3、CaO为特征,TiO_2含量与俯冲带之上地幔橄榄岩中含量相当,稀土配分曲线为轻稀土富集型,微量元素受蚀变作用影响,呈现出两种不同的曲线特征。镁铁质岩石可分为两组:I组镁铁质岩具有高MgO、低Al_2O_3,LREE轻微富集,富集大离子亲石元素,亏损Nb、Ta的特征,形成于消减带相关的岛弧环境;Ⅱ组镁铁质岩具有富碱、TiO_2,且呈LREE显著富集的右倾稀土配分曲线特征,富集大离子亲石元素,Nb、Ta正异常特征,代表了洋盆中海山或洋岛的残片。I组镁铁质岩中两个辉长岩岩块的LA-ICP-MS锆石UPb年龄分别为512.1±7.2Ma(MSWD=0.014)和531±12Ma(MSWD=0.17),与巴尔鲁克蛇绿岩、唐巴勒蛇绿岩中镁铁质岩岩块获得的锆石U-Pb年龄相吻合,且这三条蛇绿岩都具有SSZ型蛇绿岩的地球化学特征,可能为不同环境下同一洋盆的演化产物。     

Detection of underground cavities by combining gravity,magnetic and ground penetrating radar surveys: a case study from the Zaragoza area,NE Spain

A geophysical survey routine is proposed to detect underground cavities and dolines; it is based on the sequential application of magnetic, low-frequency ground penetrating radar (GPR) and microgravity techniques. A case study near Zaragoza (Ebro valley, Spain) demonstrates the applicability of these methods. The strong contrast of magnetic and electromagnetic properties (and to a lesser scale, of density) between the doline filling and the surrounding stratified Tertiary and Quaternary rocks allows the shape of filled cavities to be clearly outlined by these methods.     

Estimation of Groundwater and Nutrient Fluxes to the Neuse River Estuary, North Carolina

A study was conducted between April 2004 and September 2005 to estimate groundwater and nutrient discharge to the Neuse River estuary in North Carolina. The largest groundwater fluxes were observed to occur generally within 20 m of the shoreline. Groundwater flux estimates based on seepage meter measurements ranged from 2.86?×?10⁸ to 4.33?×?10⁸ m³ annually and are comparable to estimates made using radon, a simple water-budget method, and estimates derived by using Darcy’s Law and previously published general aquifer characteristics of the area. The lower groundwater flux estimate (equal to about 9 m³ s^?1), which assumed the narrowest groundwater discharge zone (20 m) of three zone widths selected for an area west of New Bern, North Carolina, most closely agrees with groundwater flux estimates made using radon (3–9 m³ s^?1) and Darcy’s Law (about 9 m³ s^?1). A groundwater flux of 9 m³ s^?1 is about 40% of the surface-water flow to the Neuse River estuary between Streets Ferry and the mouth of the estuary and about 7% of the surface-water inflow from areas upstream. Estimates of annual nitrogen (333 tonnes) and phosphorus (66 tonnes) fluxes from groundwater to the estuary, based on this analysis, are less than 6% of the nitrogen and phosphorus inputs derived from all sources (excluding oceanic inputs), and approximately 8% of the nitrogen and 17% of the phosphorus annual inputs from surface-water inflow to the Neuse River estuary assuming a mean annual precipitation of 1.27 m. We provide quantitative evidence, derived from three methods, that the contribution of water and nutrients from groundwater discharge to the Neuse River estuary is relatively minor, particularly compared with upstream sources of water and nutrients and with bottom sediment sources of nutrients. Locally high groundwater discharges do occur, however, and could help explain the occurrence of localized phytoplankton blooms, submerged aquatic vegetation, or fish kills.     

Importance of water quality to nekton habitat use in a North Carolina Branch estuary

Nekton abundance and water quality were examined over 8 yr (1986–1993) in Isaac Creek, a small (2.5 km long), shallow (1–2 m), estuarine creek draining to Adams Creek (Neuse River system), North Carolina, United States. Water quality and nekton were sampled at 8 to 12 stations at 2–3 wk intervals from April to October (76 dates). The nekton assemblage, sampled by trawl, included 42 taxa but was dominated by 11 species (7 fish and 4 decapod crustaceans). Nekton and water quality (temperature, salinity, dissolved oxygen [DO], salinity gradient) data were grouped and analyzed by three (upper, middle, and lower) creek zones to determine if estimated abundance was correlated with water quality. Potentially stressful water quality conditions for salinity (<5 ppt), temperature (>30°C in morning), and DO (<2 mg 1⁻¹) mainly occurred in the upper and middle zones. The most frequent occurrence of potentially stressful conditions for salinity was in the spring and for dissolved oxygen and temperature in middle to late summer. The frequency of potentially stressful conditions increased during a 3-yr period following timber harvest of a large portion of the watershed. Canonical correspondence analysis (CCA) suggested little correlation between the top 11 species and water quality and indicated an assemblage with regular seasonal changes. Comparison of nekton use of the middle and upper zones of the creek for 3-yr pre- and post-harvest periods showed an increase in proportion of nekton caught in those zones, despite the higher frequency of potentially stressful water quality conditions. This observation suggests that a complex set of factors, including water quality, influence the pattern of nekton use in Isaac Creek.     

Recruitment and growth of the Eastern oyster,Crassostrea virginica,in North Carolina

The effects of location, salinity, and depth on recruitment and growth of the eastern oyster Crassostrea virginica in Pamlico and Core sounds, North Carolina, were investigated from 1988 to 1990. We measured length and density of spat settling on oyster cultch deployed at deep (～3 m) and shallow (～1 m) depths at six sites in areas with low salinity and six sites in areas with high salinity. These data were compared with similar data taken at some of these sites by the North Carolina Division of Marine Fisheries since 1981 as part of their cultch planting program. Recruitment was generally greater in the high salinity sites, compared to the low salinity sites. Recruitment was less at shallow depths compared to deeper depths. In all three years the highest recruitment occurred in August and September, corresponding to the months of maximum water temperature. Recruitment was highly variable in space and time, but appeared to diminish from 1988 to 1990. Recruitment was reduced by sedimentation and a variety of sessile organisms. All sites appeared to have a similar potential for growth.     

Abundance and size of larval fishes outside the entrance to Beaufort Inlet, North Carolina

Synoptic ichthyoplankton sampling was conducted on two transects, one on either side of Beaufort Inlet, North Carolina, during the winter immigration season of seven ocean-spawned, estuarine-dependent fishes;Brevoortia tyrannus (Atlantic menhaden),Leiostomus xanthurus (spot),Micropogonias undulatus (Atlantic croaker),Lagodon rhomboides (pinfish),Paralichthys albigutta (Gulf flounder),P. dentatus (summer flounder), andP. lethostigma (southern flounder). Densities and lengths of larvae were significantly different among sampling dates, with distance offshore, and between sides of the inlet. Flood-tide stage had minimal effect on larval densities and lengths except forP. albigutta andP. lethostigma. Changes in larval densities with distance offshore were not coherent among species; densities ofB. tyrammus increased offshore whereas densities of the other species decreased offshore. Average larval densities on a sampling date were coherent among species. Patterns in larval lengths were also coherent among the four non-flounder species. Larval densities outside of Beaufort Inlet were correlated with larval densities inside of Beaufort Inlet. Larval densities outside of Beaufort Inlet were also correlated with the north component of the wind, nearshore water temperature, and distance to the mid-shelf front. Differences in larval density across the inlet were significantly correlated with the east component of the wind. The patterns in larval densities outside of Beaufort Inlet were complex and apparently influenced by both the physical processes that supply larvae to the nearshore region and nearshore physical dynamics.     

Phytoplankton population dynamics and productivity in a sewage-enriched tidal Creek in North Carolina

Calico Creek differs from neighboring estuaries in that it receives sewage effluent, and its waters therefore contain ample nutrients. High nutrient levels enable the phytoplankton population, which is probably light-limited, to reach densities of 10⁹ cells·1^?1 during the summer, 2 to 3 orders of magnitude higher than the surrounding, nutrient-limited populations. At cell densities greater than 10⁸ cells·1^?1 the number of dominant species is greatly reduced, and the level of diversity drops sharply. Calico Creek also differs by being very shallow; the population can be drastically affected by high runoff. The productivity of both the phytoplankton and the surroundingSpartina marsh is much higher than the neighboring unpolluted estuaries. Unlike the larger and more stable estuaries nearby, the dependence of the population on the effluent for nutrients, the possibility of toxic materials entering the creek with the effluent, and its small size make Calico Creek subject to sudden change.     

Quaternary coastal lithofacies,sequence development and stratigraphy in a passive margin setting,North Carolina and Virginia,USA

Lithofacies analysis is fundamental to unravelling the succession of depositional environments associated with sea‐level fluctuations. These successions and their timing are often poorly understood. This report defines lithofacies encountered within the north‐eastern North Carolina and south‐eastern Virginia Quaternary section, interprets their depositional environments, presents a model for coastal depositional sequence development in a passive margin setting and uses this understanding to develop the stratigraphy and Quaternary evolutionary history of the region. Data were obtained from numerous drill cores and outcrops. Chronology was based on age estimates acquired using optically stimulated luminescence, amino acid racemization, Uranium series and radiocarbon dating techniques. Geomorphic patterns were identified and interpreted using light detection and ranging imagery. Since lithofacies occurrence, distribution and stratigraphic patterns are different on interfluves than in palaeo‐valleys, this study focused on interfluves to obtain a record of highstand sea‐level cycles with minimal alteration by fluvial processes during subsequent lowstands. Nine primary lithofacies and four diagenetic facies were identified in outcrops and cores. The uppermost depositional sequence on interfluves exhibits an upward succession from shelly marine lithofacies to tidal estuarine lithofacies and is bounded below by a marine ravinement surface and above by the modern land surface. Older depositional sequences in the subsurface are typically bounded above and below by marine ravinement surfaces. Portions of seven depositional sequences were recognized and interpreted to represent deposition from late middle Pleistocene to present. Erosional processes associated with each successive depositional sequence removed portions of older depositional sequences. The stratigraphic record of the most recent sea‐level highstands (Marine Isotope Stage 5a and Marine Isotope Stage 3) is best preserved. Glacio‐isostatic adjustment has influenced depositional patterns so that deposits associated with late Quaternary sea‐level highstands (Marine Isotope Stages 5c, 5a and 3), which did not reach as high as present sea‐level according to equatorial eustatic records, are uplifted and emergent within the study area.