قاع فيضات الضاحكية-نافذة في الصخر

نافذة في الصخر من صنع الرياح والرمال والزمن.

بدأت هذه النافذة بالتشكل في صخر جروف الهضبة الشرقية قبل الاف السنين كفتحة صغيرة او فراغ في جسم جدار صخري غير سميك نسبيا وما ان تمكنت المياه والرياح من تخللها حتى بدأت في الاتساع تدريجيا اذ تحمل الرياح معها حبيبات الرمل القاسية فتصطدم في جوانبها وتعمل على حتها . تتباطيء سرعة الحت عند الجزء العلوي من التكوين ذو اللون البني الداكن وذلك لانه اكثر مقاومة للتجوية (التجوية التفاضلية) وتتسارع في الطبقة البيضاء الاكثرعرضة للتجوية والتأكل للتسع الحفرة بشكل اسرع افقيا والى الاسفل وبعد مضي فترة من الزمن تتسع النافذه وقد تصل اقطارها السفلية الى الارض لتصبح قوس صخري شريطة ان تتمكن الطبقات العليا الاشد صلابة من الصمود في وجه الزمن وعدم الانهيار.

Window in the escarpment rocks of the Eastern Plateau of Jordan
Subaerial weathering and continues hammering of the vertical narrow succession by airborne fine particles of sand driven by winds weathered the weaker rock first (differential weathering) creating a window in the cliff. Wind, water and time will continue to erode the weaker parts of the rock until the lower regions of the window reach ground level to create an arch assuming the upper stratum continues to withstand the elements and does not collapse. Since weathering is supposed to be somewhat more even along the face of the cliff, the window probably started when a part of the cliff collapsed opening a small window for air to be channeled through and ever since it continued to grow.

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Amber-a time capsule

For thousands of years amber captured the imagination of mankind with its lustrous beauty and the unique inclusions found within. It opened a window for the professional and the curious alike to take a glimpse at a time long gone yet frozen like a snapshot inside a protective capsule that has managed to travel through time and space deep within the restless layers of the ever-changing earth. The word itself “amber” originated from the Arabic word “anbar” which refers to fossilized tree sap (Figure 1) produced by ancient trees that occupied earth millions of years ago. The resin (Figure 2) is produced when the tree is injured. The fresh sticky substance covers the injury and protects the tree in a manner similar to blood gushing from a wound. The blood congeals and protects the injury from infection and seals the affected spot allowing the healing process to proceed. Not all trees produce the same amount of resin. Certain trees produce copious amounts and several explanations were proposed to explain why such heavy secretion may take place: 1: As a reaction to damage caused either by insects, storms, animals or disease. 2: As a defense against insect or fungal disease. 3: To attract insect pollinators to aid in reproduction. 4: A bi-product of seasonal growth. Studies conducted in Russia indicated that certain types of trees, such as the Kuari pines found only in New Zealand, produce heavy amounts of resin during particular periods of the year.

Once the resin is exuded from the tree, it begins to go through a number of stages before it turns into amber. The first stage involves a slow cross chain linking of the resin’s molecular structure. Once this process is completed, the resin becomes hard and brittle and could be called copal. The second stage involves the transformation of copal into amber by the evaporation of oils or turpenes which slowly permeate out of the copal. This stage, which involves the transformation of copal into amber may take many millions of years before it is completed and only then can the fossilized resin by called amber.

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Centipede in 40-50 ,million year old Baltic amber