Calibration by OxCal 4.1 [Bronk Ramsey, 1995, 2009] using the IntCal 04 atmospheric calibration curve [Reimer et al., 2004]
Kagan et al (2011) modeled this section with boundaries at 0,230,500, and 537 cm. depths using OxCal P_Sequence (k factor = 1) deposition model (see section 4.1 of paper reproduced at bottom of table)
Age Depth Model of Kagan et al (2011) for En Feshka shown in Figure 3
Alternate Age Depth Model of Kagan et al (2011) for En Feshka shown in Figure S1
Sample ID - EFW samples are from the Ein Feshkha outcrop, DSF samples are from the 1997 GFZ/GSI Ein Feshkha core
EFW samples collected by Elisa Kagan prior to 2011, DSF samples likely collected by Claudia Migowski prior to 2001
Gully Depth below Fan Delta surface
En Feshka Radiocarbon
En Feshka Outcrop & Core Radiocarbon
4.1. Ein Feshkha Chronology from Kagan et al (2011)
[23] For the EFE section the chronological model is based on the treatment of seventeen radiocarbon ages of which five were excluded as outliers (Table 2). In the last 2500 years,
the period with historic earthquake correlations and implications, there were only two outliers, both of which were too old and probably represent long-lived organic debris from the shores.
One of these two outlier samples also appeared in the work of Neumann et al. [2007] (169 cm depth) and was considered an outlier. One interval, from 230 to 390 cm, is slightly anomalous:
the sediment is much darker than the rest of the section and has less aragonite layers. Within this interval, between 230 and 330 cm, we did not recognize any deformed layers (Table 3).
No organic debris was found from 220 to 410 cm depth (Table 2 and Figure 3).
[24] Several different models were run: (1) No internal boundaries from 0 to 500 m depth; 500 cm to base modeled separately.
(2) Two internal boundaries in the 0-537 cm interval, at 230 and at 500 cm depth, which allow, but do not force, the model to have sediment rate changes.
(3) The 0-230 cm and 390-500 cm deep segments run separately. (4) Various other options with different boundaries and various outliers.
[25] We choose option 2 from the above list (Figure 3). This curve yields the best "agreement indexes" for the Bayesian model, with one index value under
60% (at 17%) while the other models have lower agreement indexes. Alternative models give seismite ages (from at least the 5th century B.C. and on)
that are very similar to the chosen model and do not change the paleoseismic conclusions (for an example, see option 1 in Figure S1).
The slight facies change at 230 cm depth is allowed a degree of freedom to coincide with sedimentation rate change, but in the resulting model shows no significant rate change (see Figure 3).
[26] The chronology of the top 537 cm of the section is Bayesian-modeled as one space with two internal boundaries at 230 cm and 500 cm,
implying continuous sedimentation and allowing, but not forcing, sedimentation rate change at these boundaries.
Agreement values are found to be well above 60% at most depths of the model. The resulting model ages of the section
indicate a maximum range of 1261 B.C. to 1383 A.D., but more likely from ~1100 B.C. to 1312 A.D. (Table 2 and Figure 3).
The top unit, from 0 cm (surface) to 500 cm, shows ages that range from the 5th century B.C. to the 14th century A.D.,
with a 0.27 +/- 0.03 cm/yr sedimentation rate (based on 2 sigma age ranges). The age range of the lower unit (500 to 537 cm)
is from approximately 11th-5th century B.C. (0.07 +/- 0.03 cm/yr sedimentation). The base of the seismite-bearing investigated
section is at 590 cm, however in the bottom 53 cm no organic matter was found and therefore the age was not modeled.
The sedimentation rate of the top 500 cm calculated here (0.27 cm/yr) is approximately constant, in comparison to that
stated for the same section by Neumann et al. [2007] (0.14, 0.51, and 0.11 cm/yr for three stratigraphic units within
the same depth interval). The rates presented here, based on the new Bayesian model, are more similar to published
Holocene rates (e.g., Migowski et al. [2004]: ~0.15 cm/yr for the entire Holocene Ein Gedi core) and more congruous
with homogeneous pollen concentrations [Neumann et al., 2007], which are normally closely linked to sedimentation rate [Horowitz, 1992].
[27] The truncation of the last six centuries from the studied EFE section eliminates recording the key instrumental earthquake M6.2, 7
November 1927, the source zone of which spans the site (Figure 1). Macroseismic evidence for the 1927 A.D. instrumentally recorded
earthquake was reported along the Jordan River [Hough and Avni, 2011]. Niemi and Ben-Avraham [1994] interpreted large submarine slumps
in the northern Dead Sea basin to have been caused by this earthquake. For the purpose of the discussion (section 5), this event will
be considered recorded in the northern Dead Sea basin.