Stratified cultural remains from the Roman to Late Islamic periods in the coastal zone of Aqaba, Jordan at the northern end of the Gulf of Aqaba and analyses of thirteen sediment cores provide evidence for changes in the depositional environment during the Holocene. Local tectonic subsidence likely formed a coastal embayment ca. 8000 yr B.P. that was subsequently filled by human-induced siltation by ca. 4000 yr B.P. base on radiocarbon and microfossil analyses. Overlying sedimentation is dominated by fluvial and aeolian processes until the first century B.C. when Early Roman-Nabataean mudbrick structures were built in this area. Strong lead and copper concentrations in the sediment appear to stratigraphically constrain the Chalcolithic and Roman layers. Furthermore, an examination of archaeological sites near Aqaba suggests that people migrated to avoid the flood waters of Wadi Yutim and Wadi 'Arabah rather than moving their settlements based solely on changing sea-level.

Construction of the lower tidal lagoon at the Ayla Oasis Development in Aqaba, Jordan provided a unique opportunity to study the 3-D architecture of coastal plain sediment of the northern Gulf of Aqaba. Previous studies of sediment cores had identified a mid-Holocene transgression and a late Holocene regression. In this study, one cross-section of buried structures adjacent to the archaeological site of Tel el-Kheleifeh (8th-4th C. BCE) and two stratigraphic columns of 7 m-high outcrops that extended to a depth of 3.2 m below sea level were described and sampled for grain-size, SEM, and radiocarbon age analyses. The base of the section contains subtidal and beach sand and cobble gravel containing abundant shells and coral fragments. Three vertically stacked beachrock layers that developed in the intertidal zone indicate a rising sea level. The uppermost beachrock is found at an elevation of 1.3 m above present sea level and is constrained to be younger than 3.5 ka based on radiocarbon dating of shells. Raised reef, wave-cut notches, and other sea level indicators across the Gulf of Aqaba and northern Red Sea attest to a mid-Holocene highstand. A down-cutting event that eroded the beach sediment and is marked by an irregular unconformity and channels cut to depths below modern sea level. The channels are filled with a blue-gray gravel and sand with abundant rip-up clasts, terrestrial organic material, cross-bedding and convolute bedding which denote high flow velocities and rapid sedimentation. Radiocarbon dating of sediment above the channel constraint its age to before 3.1 ka. As rapid sea level change is not supported by regional evidence, the erosion and deposition of blue-gray channels are interpreted to represent inundation and drawdown of the sea by a tsunami. Similar erosion and deposition in low-lying areas has been documented in tsunamis in Sumatra, Chili, and the Kuril Islands.

The last glacial maximum, ca. 21,000 years ago, caused a fall in eustatic sea level of ca. 120 m below present. The low-gradient, shallow Sunda Shelf, Southeast Asia was subaerially exposed during this sea-level lowstand and experienced rising sea level thereafter. Sea level rose to a +1.3––5 m highstand ca. 6,500 cal yr BP, and then fell to modern sea level. The objective of this research is to characterize environmental change on the Sunda Shelf in response to the post-glacial rising eustatic sea level. To address this objective, six gravity cores were collected along a transect crossing the paleo-Chao Phraya incised river valley complex between peninsular Malaysia and southern Vietnam. Thirteen AMS radiocarbon samples, 130 bulk sediment magnetic susceptibility samples (BMS), 66 X-ray fluorescence spectrometry (XRF) samples, and 54 samples for the analysis of foraminiferal assemblages were used to characterize change in the depositional environments of the cored sediments. BMS, XRF, and foraminiferal analysis distinguish two main units. Unit 1 is found in the lower part of the cores and typically contains more terrestrial material than sediments further up-core as shown by higher BMS values, higher % Ti, % Al, % Fe, and lower indicators of marine influence, for example, lower % Ca, % planktonic foraminifera, and percentages of deeper water benthic foraminifera such as Heterolepa dutemplei. Unit 2 is characterized by a significant increase in % Ca, % Heterolepa dutemplei and % planktonic foraminifera ca. 6,500 cal yr BP. Unit 1 is consistent with shallower water depths and is part of a transgressive systems tract (TST, ca. 1 m thick) that terminates ca. 6,500 cal yr BP. Unit 2 represents the overlying highstand systems tract (HST, ca. 1 m thick) and is characterized by an increase in % planktonics, % Ca, and shifts in benthic foraminiferal assemblages, indicating deeper water conditions than the sediments below. This shift from a TST to a HST ca. 6500 cal yr BP is consistent with the Sunda Shelf sea-level record.

A multiproxy analyses of sediment from a 4.3 m core extracted from 25 m water depth on the shelf of the northern Gulf of Aqaba suggest shifts in depositional environments over the past 4000 yrs. Foraminifera assemblages, grain-size distribution, sediment characterization, and radiocarbon age dating indicate several eco-stratigraphic zones including two periods of aridity from ~3900 to 2900 yr BP and ~1130 yr BP to present, a transitional period from ~2900 to 2500 yr BP, and an abrupt shift to wetter conditions between ~2500 to 1130 yr BP. Furthermore, this study records two foraminifera-barren horizons at 170 and 190 cm that correlate to grain size anomalies at that depth. A tsunami wave generated sometime during 2200-1800 yr BP is one possible explanation for this occurrence. Seismic stratigraphy indicates a reflector at approximately 3 m below the seafloor that delineates the boundary between a relict, coral fringing reef horizon, U8, and the overlying U9 strata. Sedimentation rates that adjust for sediment compaction suggest the sequence lies near the foraminifera-barren horizons at ~200 cm in the core. These data signify a dramatic environmental event possibly corresponding to reef termination on the Northern Gulf of Aqaba shelf.

Two gravity cores were collected from 43 km and 90 km offshore of Kuala Terengganu (western Sunda Shelf, southern South China Sea) at ~60 m water depth to characterize late Quaternary paleoenvironments by using bulk sediment magnetic susceptibility (BMS), elemental analysis via X-ray fluorescence spectrometry (XRF), and foraminiferal analyses. Radiocarbon age estimates (using benthic foraminiferal carbonate material) indicated the nearshore core was Holocene (ca. 10,000-6,000 cal years BP) in age while the offshore core was deposited prior to the last glacial maximum (ca. 45,000 cal years BP and possibly older) during marine isotope stage (MIS) 3 (ca. 60,000 - 30,000 yrs BP) within the late Pleistocene. Elemental and BMS data agree well within both cores, except Pleistocene sediments exhibit higher BMS (ca. 1x10-4 si) and higher calcium content (ca. 2%) than Holocene sediments. These data can be interpreted as representing stronger terrestrial influence during the deposition of Pleistocene sediments or a higher dissolution of calcium carbonate. BMS data, elemental data, and micropaleontological evidence, relative abundances of 64 benthic foraminiferal species, indicate that both cores were deposited in an inner shelf environment similar to the modern shelf environment at ca. 50-60 m water depth. However, a higher ratio of planktonic foraminifera (Holocene: 0-1.3%, Pleistocene: 0-8.5%) suggests a greater influence of open marine waters in the Pleistocene sediments. The position of sea level during deposition of the late Pleistocene cored sediments is higher (ca. 60-0 m depending on the data set) than eustatic published sea-level data for MIS 3. This incongruity could be caused by age inaccuracies from limitations of the radiocarbon dating technique, although this seems unlikely as the lower range of age estimates fall within the technique and the uppermost range falls on the border of the limitations of the technique. Other options for the incongruity include large margins of error for late Pleistocene sea-level reconstruction and vertical crustal movement post-deposition from isostatic adjustment or tectonic activity.