Abstract
Isotopic analysis of rock samples showed anomalously 18O-depleted reconstructed isotopic composition of paleo-meteoric water over southern Israel between the Late Cretaceous and the Early Miocene, with δ18OW as low as -14‰ [SMOW]. This range is significantly "lighter" than the expected values for rain at the relevant paleo-latitudes (~ 8°N to 25°N). It is similar or lighter than areas with meteoric water at the present climate, in which rainfall contribution from tropical cyclone (TC) is significant. Rainfall from TCs is 18O-depleted because of the recirculation of the vapor into repeated precipitation or distillation cycles. A paleo-geographic reconstruction of the region shows that throughout the period there was a warm ocean to the east and southeast of the relevant area. Thus, TCs formed over the ocean and made landfall on the coastline at a distance of 300 to 400 km to the east. The reconstructed composition of the rainwater implies dominance of TCs at these times. Furthermore, the combination of warmer seas and lighter rainwater than at present suggests that the TCs were more dominant than in the most TC-prone coastal areas at the present climate. The results of the present study suggest that climate during the relevant time periods was very different from the present, with TC activity similar or exceeding the most TC prone locations in the world at the present climate. This might also hint that warmer sea waters in the geological past were conducive to greater TC activity than in the present climate. Answering this question requires additional research.
Original language | English |
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Pages (from-to) | 387-395 |
Number of pages | 9 |
Journal | Palaeogeography, Palaeoclimatology, Palaeoecology |
Volume | 280 |
Issue number | 3-4 |
DOIs | |
State | Published - 15 Sep 2009 |
Keywords
- Cretaceous
- Eocene
- Miocene
- Oxygen isotopes
- Paleo-meteoric waters
- Paleoclimate
- Paleotempestology
- Tropical cyclones