Ahli geologi telah menandakan fasa baharu dalam sejarah bumi selepas menemui bukti di Meghalaya, India
The current age which we are living in has been recently officially designated at the ‘Meghalayan Age’ by the International Geologic Time scale. This scale divides the history of our planet into different eons, eras, periods, epochs and ages. The timing of events on the basis of which these time periods are divided is collated by geologists and archaeologists worldwide and is based upon substantial events like continents breaking up, dramatic change in climatic conditions, extinction or emergence of certain animals and plants. The units of this scale are based upon proof and evidence of sedimentary layers which have collected over time and these layers contain different sediments, fossils and chemical isotopes. Such strata bear recordings through a passage of time which also convey associated physical and biological events. This is called geologic age dating where each of such material are assigned an age and then the likely events around it are predicted. This is how we know today that earth is 4.6 billion years old. The International Commission on Stratigraphy (IUGS) is chiefly responsible for regulating the Geologic Time Scale.
Era semasa yang kita hidup, - zaman Holosen - telah dikemas kini dan dibahagikan kepada tiga zaman geologi iaitu Holosen Awal dipanggil Greenland, Halosen Tengah dipanggil Northgrippian dan Halosen Akhir dipanggil zaman Meghlayan. Zaman Greenland ditandakan apabila zaman ais berakhir dan pemanasan bermula di bumi sekitar 12000 tahun dahulu. Zaman Northgrippian bermula sekitar 8000 tahun dahulu. Kedua-dua zaman ini ditandai dengan teras ais yang terdapat di Greenland. Zaman Meghalayan baharu yang berbeza yang kini telah dikenal pasti bermula 4,200 tahun lalu dan sehingga hari ini. Agensi International Union of Geological Sciences bertanggungjawab untuk piawaian antarabangsa dalam geologi ini. Penyelidikan telah mengambil masa sehingga lapan tahun untuk menandakan tarikh bagi umur Meghalayan.
All ages have been assigned unique names based upon their origin or start. The Greenlandian and Northgrippian ages are named for the NorthGRIP site in Greenland. This site depicts the swift warming of the planet signifying the culmination of ice age followed by a swift universal cooling at the start of Northgrippian age which was caused by entry of melted ice water into the North Atlantic. Further, around 4,200 years ago, a significantly drier phase or aridification has been identified by researchers which they have designated as the start of Meghlayan Age. The Meghalayan age is termed after a stalagmite (a type of rock formation) in Mawmlul cave located in the north eastern state Meghalaya in India to mark the exact origin of this age. The word “Meghalaya' bermaksud "tempat tinggal awan" dalam bahasa Sanskrit. Cap masa zaman ini difahamkan dengan menjelaskan bahawa stalagmit ini termendap di lantai gua daripada mendapan mineral selama beberapa ribu tahun kerana air hujan meresap ke dalam gua melalui titisan siling. Ini berlaku kemungkinan besar disebabkan oleh peralihan lautan dan peredaran atmosfera. Lapisan mineral menggambarkan perubahan dalam kerpasan dari semasa ke semasa kerana tandatangan kimia mereka menunjukkan bahawa perubahan stalagmit tunggal dalam isotop atom oksigen menyebabkan kawasan itu mengalami penurunan 20-30 peratus dalam hujan monsun. Ini dianggap sebagai bukti penting untuk penemuan ini. Malah, bukti sedemikian telah ditemui di semua tujuh benua di Bumi. 'Mega draf' ini melancarkan zaman geologi baharu. Keadaan iklim yang melampau juga akan menyebabkan keruntuhan tamadun dan memusnahkan penempatan manusia terutamanya yang terlibat dalam pertanian berhampiran Laut Mediterranean, Timur Tengah dan Asia seperti yang ditunjukkan dalam kajian. Kesan 'mega draf' ini nampaknya telah berlarutan selama lebih 200 tahun. Ramai pakar percaya acara ini sangat berkaitan dengan sebab sosial dan ekonomi.
The smallest global climatic event in the history of our planet has been discovered for the first time and it furthers our understanding of Earth’s complete geological history. This is a remarkable discovery and an addition into the history of Holocene and also archaeology. Geologists are planning to add a new epoch after the Holocene which is being called the Anthropocene which would mark the impact of humans on the geology of the planet after industrialization.
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{Anda boleh membaca kertas penyelidikan asal dengan mengklik pautan DOI yang diberikan di bawah dalam senarai sumber yang dipetik}
Sumber (s)
Suruhanjaya Antarabangsa mengenai Stratigrafi. www.stratigraphy.org. [Diakses pada 5 Ogos 2018].
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