South Africa

قبة فريدفورت

Vredefort Dome

Natural
قبة فريدفورت
الصورة من ويكيبيديا

نبذة

إن قبة فريدفورت الواقعة على مسافة 120 كلم جنوب غرب جوهانسبرغ هي جزء يدلّ على بنية الاصطدام التي أحدثها حجر نيزكي كبير الحجم بالأرض أو ندبة نيزكية. إنها الندبة الأقدم على الأرض حتى أيامنا هذه وتعود إلى 2.023 مليون سنة خلت. يبلغ شعاعها 190 كلم وهي الأكبر والأكثر تآكلاً. تشهد قبة فريدفورت على أكبر عملية تحرير للطاقة عرفتها الكرة الأرضية. فقد تسبب بتغييرات كونية مدمّرة من بينها، بحسب بعض العلماء، تغييرات كبيرة لجهة التطوّر. تشكّل القبة شهادة مهمة عن تاريخ الكرة الأرضية الجيولوجي ولها مكانة كبيرة في فهمنا لتطوّر الكرة الأرضية. لقد لعب اصطدام النيازك دوراً مهماً في تاريخ الأرض إلا أن النشاطات الجيولوجية على سطح الأرض قد أدّت إلى اختفاء آثار غالبية مواقع الاصطدام. تبقى قبّة فريدفورت المثال الأوحد على الأرض الذي يقدّم سمةً جيولوجيةً كاملة لندبة نيزكية تحت حفرة.
القيمة العالمية الاستثنائية بالإنجليزية
Brief synthesis The Vredefort Dome is 120 km south west from Johannesburg. The property represents a unique geological phenomenon formed about 2 023 million years ago and is the oldest and largest known meteorite impact structure on earth. Within the area, geological strata comprising the middle to upper zones of the earth’s crust, developed over a period of more than 3 200 million years are exposed. All the classical related characteristics of a large astrobleme are found in the property. This multi-ring structure formed by the impact scar illustrates the effect of shock metamorphism of rocks, transformation of crystal structures and shatter cones of the immense force created by the impact. Criterion (viii): Vredefort Dome is the oldest, largest, and most deeply eroded complex meteorite impact structure in the world. It is the site of the world’s greatest single, known energy release event. It contains high quality and accessible geological (outcrop) sites which demonstrate a range of geological evidences of a complex meteorite impact structure. The rural and natural landscapes of the serial property help portray the magnitude of the ring structures resulting from the impact. The serial nomination is considered to be a representative sample of a complex meteorite impact structure. A comprehensive comparative analysis with other complex meteorite impact structures demonstrated that it is the only example on earth providing a full geological profile of an astrobleme below the crater floor, thereby enabling research into the genesis and development of an astrobleme immediately post impact. Integrity The serial World Heritage property which is about 30,111 ha, is made up of a main component area of 30,108 ha and 3 satellite components of 1 ha each. The property of the Vredefort Dome includes key geological (outcrop) sites which demonstrate classic complex meteorite impact structure phenomena. A comprehensive comparative analysis with other complex meteorite impact structures demonstrated that it is the only example on earth providing a full geological profile of an astrobleme below the crater floor, thereby enabling research into the genesis and development of an astrobleme immediately post impact. This serial property is surrounded by a 5 km buffer zone that is designed to ensure the property’s long term protection against external development threats. Protection and management requirements Provision of legal protection and the establishment and maintenance of an effective management system involving all relevant stakeholders are essential requirements for this property. The national World Heritage Convention Act of 1999 is to be applied to the World Heritage property following the completion of the national designation process. Various legal instruments are also applicable to ensure the protection of the property: These pieces of legislation include the Environmental Conservation Act(Act No. 73 of 1989), the National Environmental Management Act(Act No. 107 of 1998), the Physical Planning Act(Act No. 88 of 1967), the Subdivision of Agricultural Land Act(Act No 70 of 1970), the Free State Township Ordinance(Ord. No. 9 of 1969), National Environmental Management Biodiversity Act(Act No 10 of 2004) and the Free State Nature Conservation Ordinance(Ord. No. 8 of 1969). In terms of these laws, all development within or outside the property is subjected to an environmental impact assessment. Once the World Heritage Convention Act also applies to this property, it will automatically be recognized as a protected area in terms of the National Environmental Management: Protected Areas (Act 57 of 2003). Protection in terms of the latter legislation also implies that mining or prospecting will be completely prohibited within the property or its buffer zone. The management of the property is to be guided by a multi-stakeholder Vredefort Dome Steering Committee and carried out on an interim basis by the Vredefort Dome Inter-Provincial Task Team. A framework defining roles and responsibilities is required. The future Management Authority is to oversee the implementation of the integrated management plan, taking into account the existing State Party’s action plan and draft management guidelines regarding the coordination of land-uses, development pressures, visual integrity, presentation and visitation of this World Heritage property. An integrated management plan is required for the serial property so as to address the critical issues of the enforcement of the special land use planning requirements for the private property farmlands within the serial property, the preservation of the aesthetic rural/natural landscape and the protection, presentation of and public access to the clearly defined key satellite components. These conditions are essential to ensure that active conservation management is possible.

Discussion

سجّل الدخول للانضمام إلى النقاش

سجّل الدخول للتعليق

لا تعليقات بعد. كن أول من يشاركنا رأيه!

سجّل زيارتك

سجّل الدخول لتتبّع زياراتك

تسجيل الدخول

المجتمع
0
شخصيًا
0
افتراضي
0
أرغب في الذهاب