The magnesite originated from the peridotite by weathering.是什么意思？

The magnesite originated from the peridotite by weathering.

菱镁矿是由橄榄岩风化形成的.

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

magnesite

n. 菱镁矿；

例句
Chromite and / or magnesite mineralization is usually related to the ophiolites.
铬铁矿及(或)菱镁矿化通常是与蛇绿岩有关.

originated

v. 起源于，来自，产生( originate的过去式和过去分词 )，创造，创始，开创；

例句
The pain originated from a point in his right thigh.
疼痛是从他右大腿的某处开始的。

from

prep. （表示时间）从…，（表示原因）因为，（表示来源）来自…，（表示分离）与…分离[隔开]；

例句
...an abortive attempt to prevent the current President from taking office.
企图阻止现任总统连任的失败尝试

by

prep. 在…旁边，表示方式，由于，经过；adv. 经过，表示保留或保存时用，短暂拜访；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

weathering

n. 侵蚀，风化，雨蚀；

例句
The soil is depleted first by having crops grown in it and second by natural weathering and bacterial action.
土壤首先是被种植其中的作物消耗掉，其次受自然风化和细菌活动的侵蚀。