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An immense chaotic body offshore Israel: 3D mapping
of primary and secondary boundaries
Elisheva Paldor1,*, Moshe Politi1, Benjamin Medvedev1,2, Amotz Agnon1
1
Institute of Earth Sciences, The Hebrew University, Jerusalem 91904, Israel
2 Schlumberger Petroleum Services, Parkstraat 83 Den Haag, the Netherlands
* Present address: Geological Survey of Israel, 30 Malkhe Israel, Jerusalem, 95501
ElishevaP@gsi.gov.il, moshep22@gmail.com, bmedvedev@slb.com, amotz@huji.ac.il
Introduction
Seismic reflectors lose coherence and, in places, vanish completely, in the
chaotic zone (mainly evident in Yitzhak-Gabriella Pliocene 3D seismics). The zone
seems to have been formed by an east-west trending slide on top of Pliocene
units (Post-Messinian). In this work we resolve the slide’s unique boundaries,
introduce a lateral division, and define relations to Palmachim disturbance.
(i) completely Chaotic zone; (ii) normal faulting zone upslope; (iii) folding zone downslope;
(iv) decay zone – thinner section with clearer reflectors. The three horizons marked in the
figure (sea bed, base chaotic zone and M reflector) are marked in all other sections with
the same colors. Figure 3 is an enlargement of figure 2; each bracket corresponds to the
brackets in figure 2 with the same color.
(iv)
Figure 1
Figure 1: location map of the research area. The ISC (Israel Slump Complex) as
mapped by Martinez et al., (2005), Basin research.
(iii)
Palmachim
Lateral Division
(ii)
Line 2031-IS in figure 4
Tel-Aviv-Yafo
(i)
Figure 4
Hall (1996)
Figure 2
(i)
(ii)
(iii)
(iv)
Boundaries and relation to Palmachim disturbance
Figure 2 displays western boundary of slide – part of the thickness of the disturbed
zone decreases constantly. Figure 5 shows eastern boundary in three parallel sections
(a, b & c in figure 4) characterized by sharp and steep walls. The slide is detached by a
fault with a small throw and a scar. In figure 6 the northern and southern boundaries
are visible – the slide is limited by regional Pre-Messinian structures. Note the
relation to Palmachim disturbance that sweeps the chaotic layer and therefore
constrains the chaotic slide age – around late Pliocene, based on Garfunkel et al.,
(1979), Geol. Surv. Isr. Bull 72. Moreover, it shows two different phases of sliding with
completely different characteristics, in the same geographical area. All these findings
give way for a better understanding of the disturbed zone geometry, its boundaries
and the mechanism of its creation and lead us another step towards evaluating this
unique body.
Figure 3a
(i)
(ii)
Figure 5
Line 1010-IS in figure 4
(iii)
(iv)
Figure 6
Figure 3b
Figure 2: line TGS2031 trending east-west across the chaotic zone. The disturbed
zone is laterally divided into four main units, by characteristics of constituent
reflectors:
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Acknowledgment
We would like to thank Schlumberger company, The Geological Survey of Israel and Prof.
Moshe Reshef from Tel-Aviv University for their much valued assistance. This research
was partly funded by the Ministry of Energy.