Fracture analysis and tectonic implications of Hajjah District, Yemen Arab Republic

Abstract EN

The present study principally deals with quantitative analysis of fractures in both Precambrian rocks including mctuvolc ani cs.

mctagub bros .

syntectonic granitoids and late-tectonic granitoids as well as scdimcntary rock s of Jurassic Period e xpos ed in Hajjah district located at the northwestern part of Yemen Arab Republic .

Aerial ph otograph s and field wo rk we re utili zed to identify the fractures .

1202 fra ctures of a total length of 1421.X kilometers were identified .

A multi-stage procedure is adopted for their recognition .

The preferred ori entations o f the fracture pattern arc WNW a nd NW for Precambrian rock s .

and EN E and NNE for sedimentary rock s.

Highest fracture density is reported in rnctagabbros .

The structural pattern of the pr es ent area is governed mainly by faulting and less by folding .

The fracture pattern is compatible to a large extent with the major tectonic trends identified in Yem en Arab Republic.

The recogni zed fracture pattern is believed to bel ong to two different episodes.

The WNW pauern (Red Sea trend) occurred during the Nujd Orogeny (Late Pr oterozoic- Cambri an ) .

The ENE and NE pattern (Gulf of Aq aba trend) belongs to Post Jurassic Orogeny .