[B-CG04] Decoding the history of Earth: From Hadean to the present

[BCG04-07] Reconstruct BIF bearing volcano-sedimentary sequence of Neoproterozoic, El-Dabbah Formation, Central Eastern Desert, Egypt

*Shoichi Kiyokawa¹, TAISHI SUZUKI¹, Kenji Horie², Mami Takehara², Maher Dawoud³ (1.Department of Earth and Planetary Sciences Faculty of sciences, Kyuushu University, 2.National Institute of Polar Research, 3. Menoufiya University)

Keywords:neoproterozoic, central East Desret, Banded Iron Formation

The El-Dabbah Group records a history of oceanic island arc accretion, collision, and collapse within the northern East African Orogeny during 770-570 Ma in Neoproterozoic.The El-Dabbah Group is an iron formation containing metavolcanic rocks in the Nubian Shield, Central Eastern Desert, Egypt. It preserves a sequence of relatively undeformed lower greenschist-facies rocks, overlain by subaerial sedimentary strata deposited in strike-slip basins (the Atsham Formation and the Hammamat Group). This formation includes a metavolcanics succession (>5500 m thick) containing three members, including coarse massive metavolcanic rock, pillow lavas, volcaniclastics with banded iron formation, and bedded volcaniclastic rock.At least 14 iron formations successions have been identified stratigraphically middle unit within 5500m thick volcaniclastic sequence at which are interbedded with greenish and black shales. Iron oxide beds most likely originated from dissolved Fe²⁺ sourced from oceanic arc volcanism, with repeated iron precipitation occurring during successive volcanically active periods. Four faulting were distinguished within the El-Dabbah area: (1) top-to-the-S low-angle thrusting; (2) NNE side down normal faulting; (3) sinistral displacement on north–south faults; and (4) WNE trend N-side-down normal faulting with the Hammamat Group. We obtained the crystallization ages of a granite (638.1 ± 2.9 Ma) and a quartz porphyry (659.6 ± 3.0 Ma). The detrital zircon age of the Hammamat Group show peaks at 650, 680, and 790 Ma. The El Dabbar Group formed several iron formations within relative proximal basin with hydrothermal section, which may be not related glacial condition.