Kiss the Mediterranean goodbye. Ditto the Red Sea and its wonderland of coral reefs and exotic sea life. And prepare for the day when San Francisco has a gritty new suburb: Los Angeles. Indeed, much of Southern California, including the Baja Peninsula, will eventually migrate up the west coast to make Alaska even more gargantuan.

向地中海吻別。紅海及其珊瑚礁奇景和珍奇海洋生物也再見了。有朝一日，洛杉磯將成為舊金山佈滿砂礫的新郊區。沒錯，南加州大半地區，包括下加利福尼亞半島，終將沿西岸北移，使阿拉斯加州成為巨無霸。

Geologists have long prided themselves on their ability to peer into the distant past and discern the slow movements of land and sea that have continuously revised the planet's face over eons. Now, drawing on new insights, theories, measurements and technologies — and perhaps a bit of scientific bravado — they are forecasting the shape of terra firma in the distant future.

地質學家長久以來一直以能窺探遙遠的過去及察覺陸地和海洋緩慢的移動為榮，這種緩慢的移動不斷修正數十億年來地球的面貌。現在，憑藉新的洞見、理論、測量和技術，以及也許再加上一點科學上的虛張聲勢，他們正在預測遙遠的未來陸地的形貌。

While peering 50 million years into the future may seem like a stretch, geologists consider such spans of time the blink of an eye. If one year represented Earth's past, 50 million years would equal less than 4 days, or about the limit of accurate weather forecasts.

窺視未來5000萬年，也許像一段相當漫長的時間，地質學家卻認為，這段時間只是一眨眼，一瞬間。如果一年代表地球的過去，則5000萬年還不到四天，或大約正確天氣預測的極限。

"Fifty million is fairly straightforward," said Christopher R. Scotese, a geologist at the University of Texas, Arlington, who has pioneered the predictions in recent years. "It's like you're driving on the highway and you want to know where you're going to be in 10 minutes. You check the speedometer, do a calculation, and project your present motion.

「5000萬年的預測相當直接明瞭，」阿靈頓德州大學地質學家史柯提斯是近年來地質預測的先驅。「就像在高速公路上開車，你想知道十分鐘後會在哪裡，你查查里程表，計算一下，預測你目前的動態。」

Forecasts of future continental motion developed slowly as offshoots of the theory of plate tectonics, which won acceptance in the 1960s and 1970s, shattering old dogmas of continental immobility. The theory of plate tectonics holds that the surface of Earth is composed of a dozen or so huge crustal slabs that float on a sea of partially molten rock. Over ages, hot convection currents in this sea, as well as gravitational forces, move the plates and their superimposed continents and ocean basins, tearing them apart and rearranging them like pieces of a giant jigsaw puzzle.

預測未來大陸塊的動態，漸漸發展成地板構造論的分支，在1960和1970年代成為定論，並粉碎大陸塊靜止不動的舊說。板塊構造論認為，地球表面由十來個巨大的地殼板塊構成，漂浮在浩瀚如海的部分熔岩上。隨著歲月流逝，海中熱對流及重力移動板塊及覆蓋在上面的大陸塊和海洋盆地，將它們撕裂再重新組合，如大拼圖遊戲的碎片。

In 1970, Robert S. Dietz, who uncovered major clues to plate movement in the deep sea, wrote a Scientific American article on the breakup of Pangea. He also took a first step toward predicting the future, sketched out plausible continental shifts for the next 50 million years, and projected their local repercussions.

1970年，狄耶茲發現深洋板塊移動的重大線索，並在《科學人》雜誌上撰文，談盤古大陸的分裂。他也在預測未來上跨出第一步，描繪未來5000萬年大陸板塊可能的移動，並推測它們對當地的影響。

Such visualizations caught the eye of Dr. Scotese in the late 1970s when he was a graduate student at the University of Chicago. In 1982, he got a call from Discover magazine asking if he would consider a bigger project: envisioning Earth not 50 million years from now but 200 million.

這種想像在1970年代末引起史柯提斯注意，他當時還是芝加哥大學研究生。1982年，他接到Discover雜誌電話，問他是否願考慮一項更大型的計畫：展望兩億年後的地球，而不是五千萬年後的。

Dr. Scotese drew a series of futuristic maps and, in the 1990s, found an ideal way to communicate his increasingly detailed visions of the terrestrial past and future: over the Internet. Today, Dr. Scotese's Web site, www.scotese.com, which he started in 1998, showcases his work, called the Paleomap Project.

史柯提斯畫了一系列未來學的地圖，並在1990年代透過網路，找到理想的方式，傳達他有關地球過去和未來日愈詳盡的視象。今天，史柯提斯在1998年開始架設的網站www.scotese.com，已經成為展示他研究成果的櫥窗，叫做「古地圖研究計畫」。

Today, some of his most ambitious efforts center on envisioning how Earth might look 250 million years from now. The easy part, Dr. Scotese said, is the continents. Their masses might change shape but seldom disappear altogether because their bedrock weighs little compared with dense ocean crust. Continents literally float above the action. So do mountains. Once formed, they tend to persist, disappearing only after ages of erosion wear them down.

今天，他最具雄圖的部分計畫，以展望地球2億5000萬年後的形貌為主。史柯提斯說，簡單的部分是大陸，它們的主要部分可能變形，但很少完全消失，因為它們的基岩和密實的海洋地殼相比，重量輕得多。大陸簡直就是在這些動作上漂浮，崇山峻嶺也是，一旦成形，就會屹立不搖，要經無數年代的侵蝕弱化才會消失。

The difficult part, he said, is predicting the development of new subduction zones in the seabed, and in comprehending how aggressively they rearrange the land.

他說，難的是預測海床新的「隱沒帶」的發展，及了解他們如何積極重整土地。

His long-term forecast, despite the uncertainties, portrays a distant time when the world's continents come together again to form a new supercontinent, which he calls Pangea Ultima.

他的長期預測，儘管充滿不確定性，呈現遙遠的未來世界的大陸板塊會再聚合，形成新超級大陸，他稱之為「終極盤古大陸」。

An animated depiction of Pangea Ultima demonstrates a bold exercise in futuristic thinking. First, the Mediterranean closes. Then — 25 million to 75 million years from now — Australia moves north, slamming into Indonesia and Malaysia before pirouetting counterclockwise to smash into the Philippines and then Asia, eventually merging with it.

動畫呈現終極盤古大陸顯示，未來學想法的大膽運作。首先，地中海消失。接著，在2500萬到7500萬年後，澳洲往北移動，撞上印尼和馬來西亞，再以逆時針方向衝撞菲律賓，接著是亞洲，最後和它結合。

Antarctica also moves north, shedding its icecap. Roughly 100 million years from now, it plows into the Indian Ocean, and 50 million years later wedges itself between Madagascar and Indonesia. The Indian Ocean becomes a virtual inland sea.

南極洲也北移，甩掉冰冠。大約一億年後，再衝撞印度洋，並在五千萬年後嵌在馬達加斯加和印尼中間，印度洋將形同內陸海洋。

Meanwhile, Dr. Scotese said, the biggest tectonic change of all — driven by a giant subduction zone — has torn through the dark Atlantic and begun to eat up seabed, slowly closing the ocean. Some 200 million years from now, the closure forces Newfoundland to smash into Africa and, a bit later, Brazil to ram into South Africa.

同時，史柯提斯說，最大的板塊改變，由巨大的隱沒帶驅動，從黝黑的大西洋撕裂，並開始吞噬海床，慢慢封閉海洋。大約兩億年後，這項封閉迫使紐芬蘭撞擊非洲，稍後巴西也會衝撞南非。

The collisions gain force; 250 million years from now, the continents will have merged into a new supercontinent that encircles what remains of the Indian Ocean.

這些撞擊力道持續增強，在2億5000萬年後，現在的大陸會和新超級大陸結合，包圍殘餘的印度洋。

"It's more like a big donut or bagel than Pangea," Dr. Scotese noted. In looking for a name, "I tried Bagelea or Donutea but figured that would trivialize the whole experience. A friend suggested Pangea Ultima — classy, like a fancy car. It implies that it's the last Pangea, which certainly isn't true, but it's the last one I'm going to come up with."

史柯提斯說：「這比較像超大甜甜圈或貝果麵包，不像盤古大陸。」在找名字時，「我想過貝果大陸或甜甜圈大陸，但怕這會整個經驗變得瑣碎，一個朋友建議終極盤古大陸：優雅時髦，像夢幻車，意味這是最後的盤古大陸，這當然不是真的，但這是我最後能想出來的。」

Over billions of years, the continents have split and joined repeatedly in a slow dance. They do so, geologists say, in two very dissimilar ways. As Dr. Scotese envisioned, they can break apart and reverse course to merge again. Or they can move apart until their paths around the planet cause them to coalesce on the far side.

數十億年間，這些大陸在慢舞中一再分分合合。地質學家說，它們以兩種完全不同的方式進行。史柯提斯預見，它們分裂後會再反向結合；或者它們分道揚鑣，直到它們繞地球而行，最後在遙遠的一方再接合。

Some forecasters see the current expansion — with no course reversal — as dominating the remainder of this tectonic cycle. Instead of the Atlantic disappearing, they say, the Pacific might slowly vanish, sending North and South America careering into Asia.

有些預測專家認為，目前的擴張將主導這個剩餘的板塊周期，不會再逆轉。他們並指稱，緩慢消失的可能不是大西洋而是太平洋，從而促成南北美洲和亞洲結合。

Sergei A. Pisarevsky, a geologist at the Tectonics Special Research Center of the University of Western Australia, calls the resulting supercontinent "Amasia." But he said his vision bore no special likelihood of coming true. "My guess," he said, "is that the Pacific should disappear."

西澳洲大學大地構造學特別研究中心地質學家皮薩瑞夫斯基稱最後的超大陸為「亞美大陸」，但他說，他的看法不一定成真，「我猜，」他說，「太平洋應該會消失。」（摘譯自紐約時報）



《詞解》

Baja Peninsula 下加利福尼亞半島
gargantuan 巨無霸
Geologists 地質學家
eons 數十億年
terra firma 陸地
plate tectonics 地球板塊構造（論）
geopredictions 地質預測
Eurasia 歐亞大陸
agglomeration 聚合
Afrasia 亞非大陸
speedometer 計速器，里程表
hot convection currents 熱對流
Pangea 盤古大陸
envisioning 展望，正視
terrestrial 地球
Paleomap Project 古地圖研究計畫
bedrock 基岩
subduction zones 隱沒帶
icecap 冰冠